WorldWideScience

Sample records for carbon balance part

  1. System analytical assessment of the carbon balance in Austria. Final report part 1: carbon balance for 1990

    International Nuclear Information System (INIS)

    Orthofer, R.

    1997-09-01

    The report contains an analysis and quantification of the fluxes in the Austrian carbon system in 1990. Following subsystems were considered: agriculture, forestry, energy transformation and use, production and consumption of goods, and waste treatment. Austrian carbon imports and exports in products and goods were also quantified. The calculations for the forestry and agriculture sectors are based on the results of a dynamic model (cf. final report part 2) and for others on existing data or experts opinions. In total, Austria releases a net of 11,2 Mio t carbon (MTC) - which equals about 41,1 Mio t of CO 2 - into the atmosphere. This is about 1/3 less than the numbers for the 1990 carbon emission inventories which for 1990 were estimated with 17,0 MTC. Reasons for the differences between emission estimates and carbon balancing are the carbon storage in Austria's forests (5,3 MTC) and the mineralization of organic wastes (1,0 MTC) as well as other minor interactions. While the main pathway of carbon fluxes to the atmosphere goes from fossil fuel extraction and imports via the energy system, a considerable portion of carbon is transferred through other systems. This means in order to be able to plan effective greenhouse gas reduction strategies, the overall system must be considered. (author)

  2. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J. (Discovery Bay Marine Laboratory, Univ. of the West Indies (JM))

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  3. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T J [Discovery Bay Marine Laboratory, Univ. of the West Indies (JM)

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  4. The carbon balance of North American wetlands

    Science.gov (United States)

    Scott D. Bridgham; J. Patrick Megonigal; Jason K. Keller; Norman b. Bliss; Carl Trettin

    2006-01-01

    We examine the carbon balance of North American wetlands by reviewing and synthesizing the published literature and soil databases. North American wetlands contain about 220 Pg C, most of which is in peat. They are a small to moderate carbon sink of about 49 Tg C yr-l, although the uncertainty around this estimate is greater than 100%, with the...

  5. Balanced Flow Meters without Moving Parts

    Science.gov (United States)

    Kelley, Anthony R.; VanBuskirk, Paul

    2008-01-01

    Balanced flow meters are recent additions to an established class of simple, rugged flow meters that contain no moving parts in contact with flow and are based on measurement of pressure drops across objects placed in flow paths. These flow meters are highly accurate, minimally intrusive, easily manufacturable, and reliable. A balanced flow meter can be easily mounted in a flow path by bolting it between conventional pipe flanges. A balanced flow meter can be used to measure the flow of any of a variety of liquids or gases, provided that it has been properly calibrated. Relative to the standard orifice-plate flow meter, the balanced flow meter introduces less turbulence and two times less permanent pressure loss and is therefore capable of offering 10 times greater accuracy and repeatability with less dissipation of energy. A secondary benefit of the reduction of turbulence is the reduction of vibration and up to 15 times less acoustic noise generation. Both the balanced flow meter and the standard orifice-plate flow meter are basically disks that contain holes and are instrumented with pressure transducers on their upstream and downstream faces. The most obvious difference between them is that the standard orifice plate contains a single, central hole while the balanced flow meter contains multiple holes. The term 'balanced' signifies that in designing the meter, the sizes and locations of the holes are determined in an optimization procedure that involves balancing of numerous factors, including volumetric flow, mass flow, dynamic pressure, kinetic energy, all in an effort to minimize such undesired effects as turbulence, pressure loss, dissipation of kinetic energy, and non-repeatability and nonlinearity of response over the anticipated range of flow conditions. Due to proper balancing of these factors, recent testing demonstrated that the balanced flow-meter performance was similar to a Venturi tube in both accuracy and pressure recovery, but featured reduced

  6. Forest fuel and carbon balances

    International Nuclear Information System (INIS)

    Lundborg, A.

    1994-10-01

    Forest fuel, i.e., branches and tops that remain after felling, are not considered to give a net surplus of carbon dioxide to the atmosphere. In order to, if possible, verify this theory a survey was made of the literature concerning different carbon flows related to forest fuel. Branches and needles that are not utilised as fuel nonetheless eventually become decomposed to carbon dioxide. Branches and stem wood are broken down in occasional cases to 60-80% already within 5-6 years but the decomposition rate varies strongly. A small amount of existing data suggest that branches and stems are broken down almost completely within 60-70 years, and earlier in some cases. Lignin is the component in needles and wood that is the most resistant to decomposition. Decomposition is favoured by optimal temperature and moisture, ground contact and ground animals. Material that is mulched during soil preparation is decomposed considerably faster than material that lies on the soil surface. Felling residues that are left on the soil are a large momentary addition to the soil's reserves of organic material but after a number of years the difference in soil organic material is small between places where fuel has been removed and places where felling residues have been left. High nitrogen deposition, fire control and effective forestry are factors that contribute to the increases in the reserves of soil organic material. It appears to be a good approximation to consider the forest fuel as being a neutral fuel as regards carbon dioxide in a longer perspective. In comparison with other biofuels and fossil fuels, forest fuel appears, together with Salix, to be the fuel that results in very little extra discharge of carbon dioxide or other greenhouse gases during its production, transport and processing. 70 refs, 5 figs, tabs

  7. Annual carbon balance of a peatland 10 yr following restoration

    Directory of Open Access Journals (Sweden)

    M. Strack

    2013-05-01

    Full Text Available Undisturbed peatlands represent long-term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2 and methane (CH4 fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 μmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, peatland restoration resulted in a large reduction in annual carbon loss from the system resulting in a carbon balance more similar to a natural

  8. Climate change, fire and the carbon balance

    International Nuclear Information System (INIS)

    Amiro, B.; Flannigan, M.

    2004-01-01

    On average, forest fires have burned 2 to 3 million hectares annually in Canada over the last twenty years. Over the last 40 years, this amounts to 20 per cent of the amount of carbon released through fossil fuel emissions in Canada. This paper analyses the extent to which climate change may contribute to a disturbance in the carbon balance due to increased fire activity. In addition, data from FLUXNET-Canada was examined, indicating that carbon fluxes from younger forests show dramatic changes in diurnal carbon flux patterns, caused by reduced photosynthetic uptake during the day and less root respiration at night. Increases in fire are expected throughout much of the boreal forest towards the end of this century, with a lengthening of the fire season and increases in severity and intensity. It was concluded that there is the possibility of a positive feedback, where climate change could cause more fires, resulting in a greater release of carbon and thereby increasing greenhouse gas concentrations. Evidence that smoke promoted positive lightning strikes while reducing precipitation was also presented. It was suggested that certain self-limiting factors may prevent a run-away scenario. Changes to human and lightning ignition patterns, for example, may have an impact. It was also suggested that research efforts should focus on refining climate change estimates that account for landscape change and other aspects that control fire in Canada. 9 refs., 2 figs

  9. Modelling fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE – Part 1: Simulating historical global burned area and fire regime

    CSIR Research Space (South Africa)

    Yue, C

    2014-01-01

    Full Text Available ., 2008; Turner et al., 1994) and biological diversity (Burton et al., 2008) and may also produce a higher rate of carbon emissions compared to small fires (Kasischke and Hoy, 2012). In some ecosystems, past climate warming is documented to have increased...

  10. Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part I evaluation of a water and carbon balance model

    Science.gov (United States)

    Shanlei Sun; Ge Sun; Peter Caldwell; Steven G. McNulty; Erika Cohen; Jingfeng Xiao; Yang Zhang

    2015-01-01

    Understanding and quantitatively evaluating the regional impacts of climate change and variability (e.g., droughts) on forest ecosystem functions (i.e., water yield, evapotranspiration, and productivity) and services (e.g., fresh water supply and carbon sequestration) is of great importance for developing climate change adaptation strategies for National Forests and...

  11. Sustainability as a part of balanced scorecard

    Directory of Open Access Journals (Sweden)

    Lucie Sara Zavodna

    2013-05-01

    Full Text Available Sustainability is a trend, which is more seriously discussed on the international and national level. But also companies in the local level are pushed to have strategies and visions, which enable better future for society, our planet and local economy. Sustainability is one of the conditions – it allows companies to implicate social, economic and environmental pillars to the company´s strategy and management. The question, which remains today is, how to measure social, economic and environmental impact on society? And more – how to enable future generations to have the same conditions as we have today? The paper provides format for a possible bridge between current strategic Balanced Scorecard system and future trend of sustainability. One of the special tools, which can be used for measuring sustainability, is Balanced Scorecard (by Kaplan and Norton in 1990s with the complement of sustainable metrics. The paper introduces three possible methods, which can be used by implementing sustainability into the Balanced Scorecard. One of these methods is described in detail. There is a focus on the sustainable indicators included as the fifth area in Balanced Scorecard model.

  12. SUSTAINABILITY AS A PART OF BALANCED SCORECARD

    Directory of Open Access Journals (Sweden)

    LUCIE SARA ZAVODNA

    2013-05-01

    Full Text Available Sustainability is a trend, which is more seriously discussed on the international and national level. But also companies in the local level are pushed to have strategies and visions, which enable better future for society, our planet and local economy. Sustainability is one of the conditions – it allows companies to implicate social, economic and environmental pillars to the company´s strategy and management. The question, which remains today is, how to measure social, economic and environmental impact on society? And more – how to enable future generations to have the same conditions as we have today? The paper provides format for a possible bridge between current strategic Balanced Scorecard system and future trend of sustainability. One of the special tools, which can be used for measuring sustainability, is Balanced Scorecard (by Kaplan and Norton in 1990s with the complement of sustainable metrics. The paper introduces three possible methods, which can be used by implementing sustainability into the Balanced Scorecard. One of these methods is described in detail. There is a focus on the sustainable indicators included as the fifth area in Balanced Scorecard model.

  13. Human footprint affects US carbon balance more than climate change

    Science.gov (United States)

    Bachelet, Dominique; Ferschweiler, Ken; Sheehan, Tim; Baker, Barry; Sleeter, Benjamin M.; Zhu, Zhiliang

    2017-01-01

    The MC2 model projects an overall increase in carbon capture in conterminous United States during the 21st century while also simulating a rise in fire causing much carbon loss. Carbon sequestration in soils is critical to prevent carbon losses from future disturbances, and we show that natural ecosystems store more carbon belowground than managed systems do. Natural and human-caused disturbances affect soil processes that shape ecosystem recovery and competitive interactions between native, exotics, and climate refugees. Tomorrow's carbon budgets will depend on how land use, natural disturbances, and climate variability will interact and affect the balance between carbon capture and release.

  14. Balance and forecasts of french carbon dioxide emissions

    International Nuclear Information System (INIS)

    1992-11-01

    This paper strikes the balance of carbon dioxide emissions in France between 1986 and 1991 and gives forecasts till 2010. Since 1986, France has reduced its efforts for energy conservation and air pollution by carbon dioxide begins to growth again in connection with consumption growth in transport area, development of computer and simulation needs

  15. Energy and carbon balances of wood cascade chains

    Energy Technology Data Exchange (ETDEWEB)

    Sathre, Roger; Gustavsson, Leif [Ecotechnology, Mid Sweden University, SE-831 25 OEstersund (Sweden)

    2006-07-15

    In this study we analyze the energy and carbon balances of various cascade chains for recovered wood lumber. Post-recovery options include reuse as lumber, reprocessing as particleboard, pulping to form paper products, and burning for energy recovery. We compare energy and carbon balances of chains of cascaded products to the balances of products obtained from virgin wood fiber or from non-wood material. We describe and quantify several mechanisms through which cascading can affect the energy and carbon balances: direct cascade effects due to different properties and logistics of virgin and recovered materials, substitution effects due to the reduced demand for non-wood materials when wood is cascaded, and land use effects due to alternative possible land uses when less timber harvest is needed because of wood cascading. In some analyses we assume the forest is a limiting resource, and in others we include a fixed amount of forest land from which biomass can be harvested for use as material or biofuel. Energy and carbon balances take into account manufacturing processes, recovery and transportation energy, material recovery losses, and forest processes. We find that land use effects have the greatest impact on energy and carbon balances, followed by substitution effects, while direct cascade effects are relatively minor. (author)

  16. Biomass energy and the global carbon balance

    International Nuclear Information System (INIS)

    Hall, D.O.; House, J.I.

    1994-01-01

    Studies on climate change and energy production increasingly recognise the crucial role of biological systems. Carbon sinks in forests (above and below ground), CO 2 emissions from deforestation, planting trees for carbon storage, and biomass as a substitute for fossil fuels are some of the key issues which arise. Halting deforestation is of paramount importance, but there is also great potential for reforestation of degraded lands, agroforestry and improved forest management. It is concluded that biomass energy plantations and other types of energy cropping could be a more effective strategy for carbon mitigation than simply growing trees as a carbon store, particularly on higher productivity lands. Use of the biomass produced as an energy source has the added advantage of a wide range of other environmental, social and economic benefits. (author)

  17. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

    DEFF Research Database (Denmark)

    Kindler, Reimo; Siemens, Jan; Kaiser, Klaus

    2011-01-01

    ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small...... solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems....

  18. Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements

    Science.gov (United States)

    Gatti, L. V.; Gloor, M.; Miller, J. B.; Doughty, C. E.; Malhi, Y.; Domingues, L. G.; Basso, L. S.; Martinewski, A.; Correia, C. S. C.; Borges, V. F.; Freitas, S.; Braz, R.; Anderson, L. O.; Rocha, H.; Grace, J.; Phillips, O. L.; Lloyd, J.

    2014-02-01

    Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48+/-0.18 petagrams of carbon per year (PgCyr-1) during the dry year but was carbon neutral (0.06+/-0.1PgCyr-1) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25+/-0.14PgCyr-1, which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39+/-0.10PgCyr-1 previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.

  19. Designing carbon markets, Part II: Carbon markets in space

    International Nuclear Information System (INIS)

    Fankhauser, Samuel; Hepburn, Cameron

    2010-01-01

    This paper analyses the design of carbon markets in space (i.e., geographically). It is part of a twin set of papers that, starting from first principles, ask what an optimal global carbon market would look like by around 2030. Our focus is on firm-level cap-and-trade systems, although much of what we say would also apply to government-level trading and carbon offset schemes. We examine the 'first principles' of spatial design to maximise flexibility and to minimise costs, including key design issues in linking national and regional carbon markets together to create a global carbon market.

  20. Testing the performance of a Dynamic Global Ecosystem Model: Water balance, carbon balance, and vegetation structure

    Science.gov (United States)

    Kucharik, Christopher J.; Foley, Jonathan A.; Delire, Christine; Fisher, Veronica A.; Coe, Michael T.; Lenters, John D.; Young-Molling, Christine; Ramankutty, Navin; Norman, John M.; Gower, Stith T.

    2000-09-01

    While a new class of Dynamic Global Ecosystem Models (DGEMs) has emerged in the past few years as an important tool for describing global biogeochemical cycles and atmosphere-biosphere interactions, these models are still largely untested. Here we analyze the behavior of a new DGEM and compare the results to global-scale observations of water balance, carbon balance, and vegetation structure. In this study, we use version 2 of the Integrated Biosphere Simulator (IBIS), which includes several major improvements and additions to the prototype model developed by Foley et al. [1996]. IBIS is designed to be a comprehensive model of the terrestrial biosphere; the model represents a wide range of processes, including land surface physics, canopy physiology, plant phenology, vegetation dynamics and competition, and carbon and nutrient cycling. The model generates global simulations of the surface water balance (e.g., runoff), the terrestrial carbon balance (e.g., net primary production, net ecosystem exchange, soil carbon, aboveground and belowground litter, and soil CO2 fluxes), and vegetation structure (e.g., biomass, leaf area index, and vegetation composition). In order to test the performance of the model, we have assembled a wide range of continental and global-scale data, including measurements of river discharge, net primary production, vegetation structure, root biomass, soil carbon, litter carbon, and soil CO2 flux. Using these field data and model results for the contemporary biosphere (1965-1994), our evaluation shows that simulated patterns of runoff, NPP, biomass, leaf area index, soil carbon, and total soil CO2 flux agree reasonably well with measurements that have been compiled from numerous ecosystems. These results also compare favorably to other global model results.

  1. Designing carbon markets. Part I: Carbon markets in time

    International Nuclear Information System (INIS)

    Fankhauser, Samuel; Hepburn, Cameron

    2010-01-01

    This paper analyses the design of carbon markets in time (i.e., intertemporally). It is part of a twin set of papers that ask, starting from first principles, what an optimal global carbon market would look like by around 2030. Our focus is on firm-level cap-and-trade systems, although much of what we say would also apply to government-level trading and carbon offset schemes. We examine the 'first principles' of temporal design that would help to maximise flexibility and to minimise costs, including banking and borrowing and other mechanisms to provide greater carbon price predictability and credibility over time.

  2. Impact of the 2015 El Niño on the Indonesian carbon balance: implications for carbon mitigation

    Science.gov (United States)

    Bowman, K. W.; Liu, J.; Bloom, A. A.; Parazoo, N.; Lee, M.; Walker, T. W.; Menemenlis, D.; Jiang, Z.; Gierach, M.; Gurney, K. R.

    2016-12-01

    The COP21 or Paris Agreement in Dec. 2015 was a landmark step in a cooperative approach to reduce anthropogenic emissions from both fossil fuel and deforestation. During that same period, one of the strongest El Niños on record led to devastating droughts, fires, and air pollution in Indonesia. We assess the impact of this El Niño on the Indonesia carbon balance using the NASA Carbon Monitoring System Flux (CMS-Flux) pilot project, which assimilates satellite observations across the entire carbon cycle to attribute the CO2 growth rate to spatially resolved surface fluxes. We assimilate new xCO2 observations from the Orbital Carbon Observatory (OCO-2) to quantify net carbon fluxes and validate those fluxes against independent in-situ atmospheric data. The contribution of biomass burning to the carbon balance is independently determined from the assimilation of Measurements of Pollution in the Troposphere (MOPITT). The impact of the concomitant drought on productively is assessed from the assimilation of new solar induced fluorescence (SIF) measurements. Using these multiple lines of evidence, we investigate the relative role of biomass burning and productivity in the contribution of Indonesia to the global atmospheric growth rate. The exceptionally long turnover rates of peat carbon pools lead to effectively irreversible carbon loss to the atmosphere. The implications of these losses to Indonesian Intended Nationally Determined Contributions (INDC) as part of the Paris agreement will be explored.

  3. Simulating the carbon balance in reclaimed forest ecosystems with the FORECAST model

    Energy Technology Data Exchange (ETDEWEB)

    Welham, C. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Forest Sciences, Forest Ecosystem Simulation Group; ForRx Consulting, Belcarra, BC (Canada); 3GreenTree Ecosystem Services Ltd., Belcarra, BC (Canada)

    2010-07-01

    Large emission sources are beginning to report their carbon footprint on an annual basis as a result of government mandates, shareholder demand for disclosure of a company's risk to climate change, and as part of corporate social responsibility initiatives. Oil sands mining is a carbon intensive activity from the perspective of carbon dioxide emissions. The intensity of carbon emissions can be mitigated through technological and process innovations. However, reclamation is the only mining-related activity that directly removes atmospheric carbon dioxide. This presentation described a modeling exercise that had 3 principal objectives, notably to simulate the carbon balance in a developing reclaimed upland forest ecosystem; to explore the relative change in carbon pools over time; and to compare the carbon balance of the reclaimed ecosystem to its natural analogue. The presentation provided a description of the model and methodology and discussed the simulation protocol. Imperial Oil's Kearl Lake operation, which was used as a test case, showed that approximately 83,000 tonnes of carbon dioxide per hectare can be sequestered per year as a result of reclamation. tabs., figs.

  4. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  5. Carbon balances during land conversion in early bioenergy systems

    Science.gov (United States)

    Zenone, T.; Chen, J.; Gelfand, I.; Robertson, G. P.; Hamilton, S. K.

    2012-12-01

    In this study, we established a field experiment and deployed seven eddy-covariance towers to quantify the roles of land use change and the subsequent carbon (C) balances of three different bioenergy systems (corn, switchgrass, and mixed prairie species) that were developed from two historical land use types: monocultural grasslands dominated by smooth brome (Bromus inermis Leyss) and lands in the Conservation Reserve Program (CRP). Three CRP fields and three cropland fields were converted to soybean in 2009 (conversion year) before establishing the cellulosic biofuel cropping systems in 2010 (establishment year). A CRP perennial grassland site was kept undisturbed as a reference. Conversion of CRP to soybean induced net C emissions during the conversion year (134 -262 g C m-2 yr-1), while in the same year the net C balance at the CRP grassland reference was -35 g C m-2 yr-1 (i.e., net C sequestration). The establishment of switchgrass and mixed prairie induced a cumulative C balance of -113 g C m-2 (switchgrass from CRP), 250 g C m-2 (switchgrass from cropland), 706 g C m-2 (mixed prairie from CRP), and 59 g C m-2 (mixed prairie from cropland) over the three-year study period. The cumulative three-year C balance of corn converted from CRP and from cropland was -151 g C m-2 and -183 g C m-2, respectively. Eddy flux measurements during cellulosic biofuel crop establishment reveal annual changes in C balance that cannot be detected using conventional mass balance approaches. When end-use of harvested biomass was considered, the C balances for all studied systems, except the reference site, exhibited large C emissions ranging from 150 to 990 g C m-2 over the three-year conversion phase.

  6. The role of ecosystem memory in predicting inter-annual variations of the tropical carbon balance.

    Science.gov (United States)

    Bloom, A. A.; Liu, J.; Bowman, K. W.; Konings, A. G.; Saatchi, S.; Worden, J. R.; Worden, H. M.; Jiang, Z.; Parazoo, N.; Williams, M. D.; Schimel, D.

    2017-12-01

    Understanding the trajectory of the tropical carbon balance remains challenging, in part due to large uncertainties in the integrated response of carbon cycle processes to climate variability. Satellite observations atmospheric CO2 from GOSAT and OCO-2, together with ancillary satellite measurements, provide crucial constraints on continental-scale terrestrial carbon fluxes. However, an integrated understanding of both climate forcings and legacy effects (or "ecosystem memory") on the terrestrial carbon balance is ultimately needed to reduce uncertainty on its future trajectory. Here we use the CARbon DAta-MOdel fraMework (CARDAMOM) diagnostic model-data fusion approach - constrained by an array of C cycle satellite surface observations, including MODIS leaf area, biomass, GOSAT solar-induced fluorescence, as well as "top-down" atmospheric inversion estimates of CO2 and CO surface fluxes from the NASA Carbon Monitoring System Flux (CMS-Flux) - to constrain and predict spatially-explicit tropical carbon state variables during 2010-2015. We find that the combined assimilation of land surface and atmospheric datasets places key constraints on the temperature sensitivity and first order carbon-water feedbacks throughout the tropics and combustion factors within biomass burning regions. By varying the duration of the assimilation period, we find that the prediction skill on inter-annual net biospheric exchange is primarily limited by record length rather than model structure and process representation. We show that across all tropical biomes, quantitative knowledge of memory effects - which account for 30-50% of interannual variations across the tropics - is critical for understanding and ultimately predicting the inter-annual tropical carbon balance.

  7. Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance

    International Nuclear Information System (INIS)

    Yang Hong; Xing Yangping; Xie Ping; Ni Leyi; Rong Kewen

    2008-01-01

    Although studies on carbon burial in lake sediments have shown that lakes are disproportionately important carbon sinks, many studies on gaseous carbon exchange across the water-air interface have demonstrated that lakes are supersaturated with CO 2 and CH 4 causing a net release of CO 2 and CH 4 to the atmosphere. In order to more accurately estimate the net carbon source/sink function of lake ecosystems, a more comprehensive carbon budget is needed, especially for gaseous carbon exchange across the water-air interface. Using two methods, overall mass balance and gas exchange and carbon burial balance, we assessed the carbon source/sink function of Lake Donghu, a subtropical, eutrophic lake, from April 2003 to March 2004. With the overall mass balance calculations, total carbon input was 14 905 t, total carbon output was 4950 t, and net carbon budget was +9955 t, suggesting that Lake Donghu was a great carbon sink. For the gas exchange and carbon burial balance, gaseous carbon (CO 2 and CH 4 ) emission across the water-air interface totaled 752 t while carbon burial in the lake sediment was 9477 t. The ratio of carbon emission into the atmosphere to carbon burial into the sediment was only 0.08. This low ratio indicates that Lake Donghu is a great carbon sink. Results showed good agreement between the two methods with both showing Lake Donghu to be a great carbon sink. This results from the high primary production of Lake Donghu, substantive allochthonous carbon inputs and intensive anthropogenic activity. Gaseous carbon emission accounted for about 15% of the total carbon output, indicating that the total output would be underestimated without including gaseous carbon exchange. - Due to high primary production, substantive allochthonous carbon inputs and intensive anthropogenic acitivity, subtropical, eutrophic Lake Donghu is a great carbon sink

  8. Environmental change and the carbon balance of Amazonian forests

    International Nuclear Information System (INIS)

    Aragao, Luiz E.O.C.; Poulter, Benjamin

    2014-01-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21. Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990's mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990's and early 2000's to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) PgCyear-1 in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP=-0.06 (-0.31 to +0.01) PgCyear -1 ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. (authors)

  9. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical

  10. The carbon-nitrogen balance of the nodule and its regulation under elevated carbon dioxide concentration.

    Science.gov (United States)

    Libault, Marc

    2014-01-01

    Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2). In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  11. Balance of emissions and consumptions of carbon dioxide in Spain

    International Nuclear Information System (INIS)

    Valero, A.; Subiela, V.; Cortes, C.

    1994-01-01

    The amount of carbon dioxide in atmosphere increase due to deforestation and anthropogenic emissions. The consumption of this gas in vegetal ecosystems must also be considered to know the net mass of CO 2 that gets into the atmosphere. This article summarizes the methodology, results and conclusions of the carbon dioxide balance in Spain by autonomous communities. The different fossil fuel consumer sectors (Thermal power plants, industry, transport, domestic and agricultural), forest biomass reduction due to fires and wood extractions for firewood are considered as sources. As sinks, natural and reforested forests, and the equivalent sea are noticed. Basically, the article presents a new methodology to estimate carbon dioxide consumption in forest biomass. The average emissions for 1981 to 1990 are presented. A per capita value of 5 t(CO 2 /year is obtained in contrast to the EC average of 8,6 t(CO 2 ) year. The resulting net balance shows that it is only consumed between 20 and 50% of the emitted CO 2 . (Author) 47 refs

  12. The impact of lateral carbon fluxes on the European carbon balance

    International Nuclear Information System (INIS)

    Ciais, P.; Hauglustaine, D.; Borges, A.V.; Abril, G.; Meybeck, M.; Folberth, G.; Janssens, I.A.

    2008-01-01

    To date, little is known about the impact of processes which cause lateral carbon fluxes over continents, and from continents to oceans on the CO 2 - and carbon budgets at local, regional and continental scales. Lateral carbon fluxes contribute to regional carbon budgets as follows: Ecosystem CO 2 sink=Ecosystem carbon accumulation + Lateral carbon fluxes. We estimated the contribution of wood and food product trade, of emission and oxidation of reduced carbon species, and of river erosion and transport as lateral carbon fluxes to the carbon balance of Europe (EU-25). The analysis is completed by new estimates of the carbon fluxes of coastal seas. We estimated that lateral transport (all processes combined) is a flux of 165 Tg C yr -1 at the scale of EU-25. The magnitude of lateral transport is thus comparable to current estimates of carbon accumulation in European forests. The main process contributing to the total lateral flux out of Europe is the flux of reduced carbon compounds, corresponding to the sum of non-CO 2 gaseous species (CH 4 , CO, hydrocarbons,... ) emitted by ecosystems and exported out of the European boundary layer by the large scale atmospheric circulation. (authors)

  13. Energy balance, carbon emissions, and costs of sortyard debris disposal

    International Nuclear Information System (INIS)

    MacDonald, A.J.

    2001-01-01

    The Forest Engineering Research Institute of Canada (FERIC), with funding from Natural Resources Canada, conducted this study to determine the main environmental and energy use issues regarding the landfilling, burning or processing of dryland sortyard debris accumulated in the wood products industry. The wood residues that are generated when logs are processed, sorted and remanufactured, have traditionally been burned or landfilled. This is no longer appropriate. Converting the large woody debris into usable products such as hog fuel or compost requires grinding, smashing or chipping into small pieces to facilitate transportation. In order to make smart decisions about alternative methods of handling sortyard debris, information is needed about the comparative amount of fuel used and carbon dioxide produced. This study compared the treatment alternatives with respect to fuel consumption, net energy balance, carbon dioxide emissions and environmental impact. Recommendations were then presented for the treatment of debris from the point of view of net energy balance and environmental impact. Life cycle techniques were used to determine the environmental impact of alternatives for managing sortyard debris. It was determined that wood wastes are valuable as hog fuel for power generation. Burning hog fuel to recover its energy offsets the need to supply energy from other sources such as natural gas. This reduces the total carbon emissions by the amount of debris that would have been burned as waste. Annual carbon emissions can be reduced by nearly half by switching from a maximize burn strategy to a maximize hog strategy that combines composting of fine materials. 2 refs., 1 tab., 1 fig

  14. Carbon and energy balances for a range of biofuels options

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, M.A.; Matthews, R.; Mortimer, N.D.

    2003-03-01

    This is the final report of a project to produce a set of baseline energy and carbon balances for a range of electricity, heat and transport fuel production systems based on biomass feedstocks. A list of 18 important biofuel technologies in the UK was selected for study of their energy and carbon balances in a consistent approach. Existing studies on these biofuel options were reviewed and their main features identified in terms of energy input, greenhouse gas emissions (carbon dioxide, methane, nitrous oxide and total), transparency and relevance. Flow charts were produced to represent the key stages of the production of biomass and its conversion to biofuels. Outputs from the study included primary energy input per delivered energy output, carbon dioxide outputs per delivered energy output, methane output per delivered energy output, nitrous oxide output per delivered energy output and total greenhouse gas requirements. The net calorific value of the biofuel is given where relevant. Biofuels studied included: biodiesel from oilseed rape and recycled vegetable oil; combined heat and power (CHP) by combustion of wood chip from forestry residues; CHP by gasification of wood chip from short rotation coppice; electricity from the combustion of miscanthus, straw, wood chip from forestry residues and wood chip from short rotation coppice; electricity from gasification of wood chip from forestry residues and wood chip from short rotation coppice; electricity by pyrolysis of wood chip from forestry residues and wood chip from short rotation coppice; ethanol from lignocellulosics, sugar beet and wheat; heat (small scale) from combustion of wood chip from forestry residues and wood chip from short rotation coppice; and rapeseed oil from oilseed rape.

  15. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments

    OpenAIRE

    Kelsey, Katharine C; Barnes, Kallie L; Ryan, Michael G; Neff, Jason C

    2014-01-01

    Background Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass ...

  16. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation modelORCHIDEE - Part 1: Simulating historical global burned area and fire regimes

    Science.gov (United States)

    C. Yue; P. Ciais; P. Cadule; K. Thonicke; S. Archibald; B. Poulter; W. M. Hao; S. Hantson; F. Mouillot; P. Friedlingstein; F. Maignan; N. Viovy

    2014-01-01

    Fire is an important global ecological process that influences the distribution of biomes, with consequences for carbon, water, and energy budgets. Therefore it is impossible to appropriately model the history and future of the terrestrial ecosystems and the climate system without including fire. This study incorporates the process-based prognostic fire module SPITFIRE...

  17. Controls on declining carbon balance with leaf age among 10 woody species in Australian woodland: do leaves have zero daily net carbon balances when they die?

    Science.gov (United States)

    Reich, Peter B; Falster, Daniel S; Ellsworth, David S; Wright, Ian J; Westoby, Mark; Oleksyn, Jacek; Lee, Tali D

    2009-01-01

    * Here, we evaluated how increased shading and declining net photosynthetic capacity regulate the decline in net carbon balance with increasing leaf age for 10 Australian woodland species. We also asked whether leaves at the age of their mean life-span have carbon balances that are positive, zero or negative. * The net carbon balances of 2307 leaves on 53 branches of the 10 species were estimated. We assessed three-dimensional architecture, canopy openness, photosynthetic light response functions and dark respiration rate across leaf age sequences on all branches. We used YPLANT to estimate light interception and to model carbon balance along the leaf age sequences. * As leaf age increased to the mean life-span, increasing shading and declining photosynthetic capacity each separately reduced daytime carbon gain by approximately 39% on average across species. Together, they reduced daytime carbon gain by 64% on average across species. * At the age of their mean life-span, almost all leaves had positive daytime carbon balances. These per leaf carbon surpluses were of a similar magnitude to the estimated whole-plant respiratory costs per leaf. Thus, the results suggest that a whole-plant economic framework, including respiratory costs, may be useful in assessing controls on leaf longevity.

  18. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments

    Science.gov (United States)

    Katherine C. Kelsey; Kallie L. Barnes; Michael G. Ryan; Jason C. Neff

    2014-01-01

    Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential...

  19. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

    Science.gov (United States)

    Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

    1997-01-01

    The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

  20. Carbon balance assessment of a natural steppe of southern Siberia by multiple constraint approach

    Directory of Open Access Journals (Sweden)

    L. Belelli Marchesini

    2007-08-01

    Full Text Available Steppe ecosystems represent an interesting case in which the assessment of carbon balance may be performed through a cross validation of the eddy covariance measurements against ecological inventory estimates of carbon exchanges (Ehman et al., 2002; Curtis et al., 2002.

    Indeed, the widespread presence of ideal conditions for the applicability of the eddy covariance technique, as vast and homogeneous grass vegetation cover over flat terrains (Baldocchi, 2003, make steppes a suitable ground to ensure a constrain to flux estimates with independent methodological approaches.

    We report about the analysis of the carbon cycle of a true steppe ecosystem in southern Siberia during the growing season of 2004 in the framework of the TCOS-Siberia project activities performed by continuous monitoring of CO2 fluxes at ecosystem scale by the eddy covariance method, fortnightly samplings of phytomass, and ingrowth cores extractions for NPP assessment, and weekly measurements of heterotrophic component of soil CO2 effluxes obtained by an experiment of root exclusion.

    The carbon balance of the monitored natural steppe was, according to micrometeorological measurements, a sink of carbon of 151.7±36.9 g C m−2, cumulated during the growing season from May to September. This result was in agreement with the independent estimate through ecological inventory which yielded a sink of 150.1 g C m−2 although this method was characterized by a large uncertainty (±130% considering the 95% confidence interval of the estimate. Uncertainties in belowground process estimates account for a large part of the error. Thus, in particular efforts to better quantify the dynamics of root biomass (growth and turnover have to be undertaken in order to reduce the uncertainties in the assessment of NPP. This assessment should be preferably based on the application of multiple methods, each one characterized by its

  1. Potential reduction of carbon emissions from Crude Palm Oil production based on energy and carbon balances

    International Nuclear Information System (INIS)

    Patthanaissaranukool, Withida; Polprasert, Chongchin; Englande, Andrew J.

    2013-01-01

    Highlights: ► We evaluate energy and carbon equivalence from CPO production based on a CBM. ► Energy spent and produced via carbon movement from palm oil mill was determined. ► Scenarios were formulated to evaluate the potential reduction of carbon emission. ► Utilization of biomass from palm oil mill shows the high potential of C-reduction. -- Abstract: This study aimed to evaluate energy and carbon equivalences (CE) associated with palm oil milling and to evaluate sustainability alternatives for energy consumption. Appropriate ways to reduce carbon emissions were also evaluated. A field survey was carried out to quantify the input and output of energy and materials following the conceptual framework of a carbon-balanced model (CBM), which exclude other non-CO 2 greenhouse gases. Survey results indicate that the electrical energy consumption for daily mill start-up averaged 18.7 ± 5.4 kWh/ton Fresh Fruit Bunches (FFBs). This energy is equivalent to 114.4 ± 33.2 kWh/ton Crude Palm Oil (CPO) which was found to be offset by that generated in the mills using palm fiber as a solid fuel. Currently, organic residues contained in the wastewater are anaerobically converted to methane. The methane is used as fuel to generate electricity and sold to an outside grid network at a generation rate of 8.1 ± 2.1 kWh/ton FFB. Based on the CBM approach, carbon emissions observed from the use of fossil energy in palm oil milling were very small; however, total carbon emission from oil palm plantation and palm oil milling were found to be 12.3 kg CE/ton FFB, resulting in the net carbon reduction in CPO production of 2.8 kg CE/ton FFB or 53.7 kg CE/ha-y. Overall, the sum of C-reduction was found 1.2 times greater than that of C-emission. This figure can be increased up to 5.5, if all biomass by-products are used as fuel to generate electricity only. The full potential for carbon reduction from palm oil milling is estimated at 0.94 kW of electric power for every hectare of

  2. Carbon balance variability in the Amazon Basin with climate change based on regular atmospheric profiling of greenhouse gases

    Science.gov (United States)

    Gatti, L.; Domingues, L. G.; Gloor, M.; Miller, J. B.; Peters, W.; Silva, M. G.; Correia, C. S. D. C.; Basso, L. S.; Alden, C. B.; Borges, V. F.; Marani, L.; Santos, R. S.; Crispim, S. P.; Sanches, A.; Costa, W. R.

    2017-12-01

    Net carbon exchange between tropical land and the atmosphere is potentially important because the vast amounts of carbon in forests and soils can be released on short time-scales e.g. via deforestation or changes in temperature and precipitation. Such changes may thus cause feedbacks on global climate as have been predicted in earth system models. The Amazon is the most significant region in the global carbon cycle, hosting by far the largest carbon vegetation and soil carbon pools ( 200 PgC). From 2010 onwards we have extended an earlier greenhouse gas measurement program to include regular vertical profiles of CO2 from the ground up to 4.5 km height at four sites along the main air-stream over the Amazon Basin. Our measurements demonstrate that surface flux signals are primarily concentrated to the lower 2 km and thus vertical profile measurements are ideally suited to estimate greenhouse gas balances. To understand the role of Amazon in global carbon budget it is important to maintain a long period of measurements that can represent the whole region. Our results already permit a range of insights about the magnitude, seasonality, inter-annual variation of carbon fluxes and their climate controls. Most recent years have been anomalously hot with the southern part of the Basin having warmed the most. Precipitation regimes also seem to have shifted with an increase in extreme floods. For the specific period we will discuss the period of 2010 to 2016, where the years 2010 and 2015/16 were anomalously dry and hot (both El Nino years) and the year 2013 was the wettest and coldest year. This period provides an interesting contrast of climatic conditions in a warming world with increasing human pressures and we will present the carbon balance for the basin during the last 7 years. We will analyze the effect of this climate variability on annual and seasonal carbon balances for these seven years using our atmospheric data. Our data permit us not only to estimate net CO2

  3. Water balance, nutrient and carbon export from a heath forest catchment in central Amazonia, Brazil

    NARCIS (Netherlands)

    Zanchi, F. .B.; Waterloo, M.J.; Tapia, A.P.; Alvarado Barrientos, M.S.; Bolson, M.A.; Luizao, F.J.; Manzi, A.O.; Dolman, A.J.

    2015-01-01

    Carbon storage values in the Amazon basin have been studied through different approaches in the last decades in order to clarify whether the rainforest ecosystem is likely to act as a sink or source for carbon in the near future. This water balance, dissolved organic carbon (DOC) and nutrient export

  4. Comparing carbon to carbon: Organic and inorganic carbon balances across nitrogen fertilization gradients in rainfed vs. irrigated Midwest US cropland

    Science.gov (United States)

    Hamilton, S. K.; McGill, B.

    2017-12-01

    The top meter of the earth's soil contains about twice the amount of carbon than the atmosphere. Agricultural management practices influence whether a cropland soil is a net carbon source or sink. These practices affect both organic and inorganic carbon cycling although the vast majority of studies examine the former. We will present results from several rarely-compared carbon fluxes: carbon dioxide emissions and sequestration from lime (calcium carbonate) weathering, dissolved gases emitted from groundwater-fed irrigation, dissolved organic carbon (DOC) leaching to groundwater, and soil organic matter storage. These were compared in a corn-soybean-wheat rotation under no-till management across a nitrogen fertilizer gradient where half of the replicated blocks are irrigated with groundwater. DOC and liming fluxes are also estimated from a complementary study in neighboring plots comparing a gradient of management practices from conventional to biologically-based annuals and perennials. These studies were conducted at the Kellogg Biological Station Long Term Ecological Research site in Michigan where previous work estimated that carbon dioxide emissions from liming accounted for about one quarter of the total global warming impact (GWI) from no-till systems—our work refines that figure. We will present a first time look at the GWI of gases dissolved in groundwater that are emitted when the water equilibrates with the atmosphere. We will explore whether nitrogen fertilizer and irrigation increase soil organic carbon sequestration by producing greater crop biomass and residues or if they enhance microbial activity, increasing decomposition of organic matter. These results are critical for more accurately estimating how intensive agricultural practices affect the carbon balance of cropping systems.

  5. Stand age and climate drive forest carbon balance recovery

    Science.gov (United States)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  6. Estimation of Regional Carbon Balance from Atmospheric Observations

    Science.gov (United States)

    Denning, S.; Uliasz, M.; Skidmore, J.

    2002-12-01

    Variations in the concentration of CO2 and other trace gases in time and space contain information about sources and sinks at regional scales. Several methods have been developed to quantitatively extract this information from atmospheric measurements. Mass-balance techniques depend on the ability to repeatedly sample the same mass of air, which involves careful attention to airmass trajectories. Inverse and adjoint techniques rely on decomposition of the source field into quasi-independent "basis functions" that are propagated through transport models and then used to synthesize optimal linear combinations that best match observations. A recently proposed method for regional flux estimation from continuous measurements at tall towers relies on time-mean vertical gradients, and requires careful trajectory analysis to map the estimates onto regional ecosystems. Each of these techniques is likely to be applied to measurements made during the North American Carbon Program. We have also explored the use of Bayesian synthesis inversion at regional scales, using a Lagrangian particle dispersion model driven by mesoscale transport fields. Influence functions were calculated for each hypothetical observation in a realistic diurnally-varying flow. These influence functions were then treated as basis functions for the purpose of separate inversions for daytime photosynthesis and 24-hour mean ecosystem respiration. Our results highlight the importance of estimating CO2 fluxes through the lateral boundaries of the model. Respiration fluxes were well constrained by one or two hypothetical towers, regardless of inflow fluxes. Time-varying assimilation fluxes were less well constrained, and much more dependent on knowledge of inflow fluxes. The small net difference between respiration and photosynthesis was the most difficult to determine, being extremely sensitive to knowledge of inflow fluxes. Finally, we explored the feasibility of directly incorporating mid-day concentration

  7. Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances

    Science.gov (United States)

    Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana

    2016-04-01

    Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.

  8. Nitrogen deposition, land cover conversion, and contemporary carbon balance of Europe

    Science.gov (United States)

    Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Jung, M.; Chen, Y.; Heimann, M.; Roedenbeck, C.; Jones, C.

    2009-04-01

    In Europe, atmospheric nitrogen deposition has more than doubled, forest cover was steadily increasing, and agricultural area was declining over the last 50 years. What effect have these changes had on the European carbon balance? In this study we estimate responses of the European land ecosystems to nitrogen deposition, land cover conversion and climate. We use results from four ecosystem process models such as BIOME-BGC, JULES, ORCHIDEE, and ORCHIDEE-CN to address this question. We discuss to which degree carbon balance of Europe has been altered by nitrogen deposition in comparison to other drivers and identify areas which carbon balance has been most effected by anthropogenic changes.

  9. Field Balancing in the Real World: Part 2

    International Nuclear Information System (INIS)

    Bracher, R.K.; Surrett, C.L.

    1999-01-01

    This paper is a follow-up to an earlier paper, Field Balancing in the Real World, which was presented at CSI Reliability Week 1997 in Nashville. Case studies of excessive vibrations on fans at ORNL will be discussed. Except for a few small sections from the earlier paper, this paper is entirely new. The case studies are new. As in the first paper, all fans are rigid-rotor type fans. Normal operation, therefore, is at less than the shaft's first critical speed. The presentation of case studies with root cause problems other than unbalance is a major departure from the first paper. We believe they belong here, since unbalance is suspected most of the time when a fan is vibrating excessively, even when it is not the root cause. In reality, unbalance is the underlying cause of the excess vibration on fans we have fixed at ORNL only about half the time. Furthermore, the analyst's credibility could be called into question upon an unsuccessful attempt at field balancing when underlying causes are later discovered and fixed. A demonstration will follow the case study presentation. The additional tests described in this paper to confirm centrifugal force (probable unbalance) will be performed

  10. Balance of Carbon Embodied in Bilateral Trade between France and China: Transfer of Emission or New Creation?

    International Nuclear Information System (INIS)

    He, Jie; Jacquemin, Johan

    2016-01-01

    We calculate the balance of carbon embodied in trade (BCET) between China and France during 1996-2005. Our results confirm China's role as a net carbon exporter and the fast increasing trend of the surplus in BCET since China's adhesion to the World Trade Organization. However, the quasi-totality of the carbon surplus is due to China's low carbon efficiency. The part of carbon emission discharged on China's territory that is directly transferred from France via trade stays very little (1-2 %). The bilateral trade between China and France seems to continue benefiting mainly from their difference in factor endowment; the environmental regulation related comparative advantage plays only a marginal role

  11. Balance of Carbon Embodied in Bilateral Trade between France and China: Transfer of Emission or New Creation?

    International Nuclear Information System (INIS)

    He, Jie; Jacquemin, Johan

    2014-01-01

    We calculate the balance of carbon embodied in trade (BCET) between China and France during 1996-2005. Our results confirm China's role as a net carbon exporter and the fast increasing trend of the surplus in BCET since China's adhesion to the World Trade Organization. However, the quasi-totality of the carbon surplus is due to China's low carbon efficiency. The part of carbon emission discharged on China's territory that is directly transferred from France via trade stays very little (1-2 %). The bilateral trade between China and France seems to continue benefiting mainly from their difference in factor endowment; the environmental regulation related comparative advantage plays only a marginal role

  12. The European carbon balance. Part 1: fossil fuel emissions

    NARCIS (Netherlands)

    Ciais, P.; Paris, J.D.; Marland, G.; Peylin, P.; Piao, S.L.; levin, I.; Pregger, T.; Scholz, Y.; Friedrich, R.; Rivier, L.; Houweling, S.; Schulze, E.D.

    2010-01-01

    We analyzed the magnitude, the trends and the uncertainties of fossil-fuel CO2 emissions in the European Union 25 member states (hereafter EU-25), based on emission inventories from energy-use statistics. The stability of emissions during the past decade at EU-25 scale masks decreasing trends in

  13. Selective Functionalization of Carbon Nanotubes: Part II

    Science.gov (United States)

    Meyyappan, Meyya; Khare, Bishun

    2010-01-01

    An alternative method of low-temperature plasma functionalization of carbon nanotubes provides for the simultaneous attachment of molecular groups of multiple (typically two or three) different species or different mixtures of species to carbon nanotubes at different locations within the same apparatus. This method is based on similar principles, and involves the use of mostly the same basic apparatus, as those of the methods described in "Low-Temperature Plasma Functionalization of Carbon Nanotubes" (ARC-14661-1), NASA Tech Briefs, Vol. 28, No. 5 (May 2004), page 45. The figure schematically depicts the basic apparatus used in the aforementioned method, with emphasis on features that distinguish the present alternative method from the other. In this method, one exploits the fact that the composition of the deposition plasma changes as the plasma flows from its source in the precursor chamber toward the nanotubes in the target chamber. As a result, carbon nanotubes mounted in the target chamber at different flow distances (d1, d2, d3 . . .) from the precursor chamber become functionalized with different species or different mixtures of species. In one series of experiments to demonstrate this method, N2 was used as the precursor gas. After the functionalization process, the carbon nanotubes from three different positions in the target chamber were examined by Fourier-transform infrared spectroscopy to identify the molecular groups that had become attached. On carbon nanotubes from d1 = 1 cm, the attached molecular groups were found to be predominantly C-N and C=N. On carbon nanotubes from d2 = 2.5 cm, the attached molecular groups were found to be predominantly C-(NH)2 and/or C=NH2. (The H2 was believed to originate as residual hydrogen present in the nanotubes.) On carbon nanotubes from d3 = 7 cm no functionalization could be detected - perhaps, it was conjectured, because this distance is downstream of the plasma source, all of the free ions and free radicals of

  14. Carbon and nitrogen balances for six shrublands across Europe

    DEFF Research Database (Denmark)

    Beier, Claus; Emmett, Bridget A.; Tietema, Albert

    2009-01-01

    ,546 g C m−2, and the systems ranged from being net sinks (126 g C m−2 a−1) to being net sources (−536 g C m−2 a−1) of carbon with the largest storage and sink of carbon at wet and cold climatic conditions. The soil carbon store dominates the carbon budget at all sites and in particular at the site...... with a cold and wet climate where soil C constitutes 95% of the total carbon in the ecosystem. Respiration of carbon from the soil organic matter pool dominated the carbon loss at all sites while carbon loss from aboveground litter decomposition appeared less important. Total belowground carbon allocation...... that in the future a climate-driven land cover change between grasslands and shrublands in Europe will likely lead to increased ecosystem C where shrublands are promoted and less where grasses are promoted. However, it also emphasizes that if feedbacks on the global carbon cycle are to be predicted it is critically...

  15. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments.

    Science.gov (United States)

    Kelsey, Katharine C; Barnes, Kallie L; Ryan, Michael G; Neff, Jason C

    2014-01-01

    Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass removed from the forest, and the occurrence and intensity of a future wildfire in this stand. In this study we investigate the carbon balance of a forest treatment with varying fates of harvested biomass, including use for bioenergy electricity production, and under varying scenarios of future disturbance and regeneration. Bioenergy is a carbon intensive energy source; in our study we find that carbon emissions from bioenergy electricity production are nearly twice that of coal for the same amount of electricity. However, some emissions from bioenergy electricity production are offset by avoided fossil fuel electricity emissions. The carbon benefit achieved by using harvested biomass for bioenergy electricity production may be increased through avoided pyrogenic emissions if the forest treatment can effectively reduce severity. Forest treatments with the use of harvested biomass for electricity generation can reduce carbon emissions to the atmosphere by offsetting fossil fuel electricity generation emissions, and potentially by avoided pyrogenic emissions due to reduced intensity and severity of a future wildfire in the treated stand. However, changes in future wildfire and regeneration regimes may affect forest carbon balance and these climate-induced changes may influence forest carbon balance as much, or more, than bioenergy production.

  16. BALANCE

    Science.gov (United States)

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  17. On the determination of the carbon balance of continents (Vladimir Ivanovich Vernadsky Medal Lecture)

    Science.gov (United States)

    Dolman, Albertus J. Han

    2013-04-01

    The carbon balance of regions, the size of continents, can be determined, albeit with significant uncertainty, by combining several bottom up and top down methods. The bottom up methods use eddy covariance techniques, biometric inventory measurements and modeling, while the top down methods use atmospheric observations and inverse models. There has been considerable progress in the last few years in determining these balances through more or less standard protocols, as highlighted for instance by studies of the REgional Carbon Cycle Assessment and Processes (RECAPP) project of the Global Carbon Project. Important areas where uncertainty creeps in are the scaling of point measurements in the bottom up methods, the sparseness of the observation network and the role of model and other errors in the inversion methods. Typically these balances hold for periods of several years. They therefore do not resolve the impact of anomalies in weather and climate directly. The role of management in these balances also differs for different continents. For instance in Europe management plays a strong role in the carbon balance, whereas for the Russian continent this is less important. Management in the European carbon balance may potentially override climatically driven variability. In contrast, for Russia, the importance of the role of forest is paramount, but there the vulnerability of the Arctic regions and permafrost is a key uncertainty for future behaviour. I hope to show the importance of these different aspects of the terrestrial carbon balance by comparing the two continents, and also discuss the significant uncertainty we still face in determining the carbon budgets of large areas. I will argue that we need to get a clearer picture of the role of management in these budgets, but also of the time variability of the budgets to be able to determine the impact of anomalous weather and the vulnerability in a future climate.

  18. Nitrogen deposition, land cover conversion, climate, and contemporary carbon balance of Europe (Invited)

    Science.gov (United States)

    Churkina, G.; Zahle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Ramankutty, N.; Roedenbeck, C.; Heimann, M.; Jones, C.

    2009-12-01

    In Europe, atmospheric nitrogen deposition has more than doubled, air temperature was rising, forest cover was steadily increasing, while agricultural area was declining over the last 50 years. What effect have these changes had on the European carbon balance? In this study we estimate responses of the European land ecosystems to nitrogen deposition, rising CO2, land cover conversion and climate change. We use results from three ecosystem process models such as BIOME-BGC, JULES, and ORCHIDEE (-CN) to address this question. We discuss to which degree carbon balance of Europe has been altered by nitrogen deposition in comparison to other drivers and identify areas which carbon balance has been affected by anthropogenic changes the most. We also analyze ecosystems carbon pools which were affected by the abovementioned environmental changes.

  19. Contribution of root to soil respiration and carbon balance in ...

    Indian Academy of Sciences (India)

    PRAKASH

    improves our understanding of the terrestrial carbon cycle ... considerably lower net ecosystem productivity in Community 2 than in Community 1 .... soil respiration chambers for each time were dried at 31ºC ..... Using existing management.

  20. "The Balancing Act"--Irish Part-Time Undergraduate Students in Higher Education

    Science.gov (United States)

    Darmody, Merike; Fleming, Bairbre

    2009-01-01

    While the numbers of part-time students has increased in higher education in Ireland, little is known about these students or about how they balance their study and other commitments. Drawing on a larger study on Irish students' experiences in higher education, this article attempts to address this gap in research and reports on Irish part-time…

  1. Balancing fast-rotating parts of hand-held machine drive

    Science.gov (United States)

    Korotkov, V. S.; Sicora, E. A.; Nadeina, L. V.; Yongzheng, Wang

    2018-03-01

    The article considers the issues related to the balancing of fast rotating parts of the hand-held machine drive including a wave transmission with intermediate rolling elements, which is constructed on the basis of the single-phase collector motor with a useful power of 1 kW and a nominal rotation frequency of 15000 rpm. The forms of balancers and their location are chosen. The method of balancing is described. The scheme for determining of residual unbalance in two correction planes is presented. Measurement results are given in tables.

  2. Carbon balance modification in Sphagnum-dominated peat mesocosms invaded by Molinia caerulea

    Science.gov (United States)

    Leroy, Fabien; Gogo, Sébastien; Guimbaud, Christophe; Bernard-Jannin, Léonard; Laggoun-Défarge, Fatima

    2017-04-01

    Plant communities have a key role in regulating greenhouse gas (GHG) emissions in peatland ecosystems and thus on their capacity to act as carbon (C) sink. However, in response to global change, boreal and temperate peatlands may shift from Sphagnum to vascular plant-dominated peatlands that may alter their C-sink function. We set up a mesocosm experiment to investigate how the main GHG fluxes (CO2 and CH4) are affected by plant community modification from Sphagnum mosses to Molinia caerulea dominance. Gross primary production (GPP), ecosystem respiration (ER) and CH4 emissions models were used to compare the C balance and global warming potential under both vegetation cover. While the annual CO2 and CH4 emissions modeling estimated an output of respectively 652 and 18 gC m-2 y-1 in Sphagnum mesocosms, it represented a release of 1473 and 50 gC m-2 y-1 with Molinia caerulea occurrence. Annual modeled GPP was respectively -495 and -1968 gC m-2 y-1 in Sphagnum and Molinia mesocosms leading to a net ecosystem carbon balance (NECB) of 175 g gC m-2 y-1 in Sphagnum mesocosms (i.e., a C-source) and of -445 gC m-2 y-1 for Molinia ones (i.e., a C-sink). Even if CH4 emission accounted for a small part of the gaseous C efflux ( 3%), its global warming potential value to get CO2 equivalent makes both plant communities acting as a warming climate effect. The vegetation shift from Sphagnum mosses to Molinia caerulea seems beneficial for C sequestration regarding the gaseous pool. However, roots and litters of Molinia caerulea could further provide substrates for C emissions and dissolved organic C release.

  3. Modelling the carbon and nitrogen balances of direct land use changes from energy crops in Denmark

    DEFF Research Database (Denmark)

    Hamelin, Lorie; Jørgensen, Uffe; Petersen, Bjørn Molt

    2012-01-01

    This paper addresses the conversion of Danish agricultural land from food/feed crops to energy crops. To this end, a life cycle inventory, which relates the input and output flows from and to the environment of 528 different crop systems, is built and described. This includes seven crops (annuals...... and perennials), two soil types (sandy loam and sand), two climate types (wet and dry), three initial soil carbon level (high, average, low), two time horizons for soil carbon changes (20 and 100 years), two residues management practices (removal and incorporation into soil) as well as three soil carbon turnover...... rate reductions in response to the absence of tillage for some perennial crops (0%, 25%, 50%). For all crop systems, nutrient balances, balances between above- and below-ground residues, soil carbon changes, biogenic carbon dioxide flows, emissions of nitrogen compounds and losses of macro...

  4. Oil geology of carbonate rock (Part 9)

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Kazuaki [Canpex Co., Ltd., Tokyo (Japan)

    1989-04-01

    As related with the oil exploration and development, the geological and environmental situation, where coral and other biological reef forms, was explained in Mubarras shoal and Bu Tinah shoal off Abu Dhabi, and the Okinawa islands. Generally, reef-natured sediment is distributed in marine areas, high in wave energy and facing open sea, and composed of coarse sediment. While, for the formation of biological reef, life must have so strong skeleton as to stand such severe wave, current and other oceanographic conditions. In Mubarras shoal, underground upheaval is found mainly in the northern part of shoal, while, in Bu Tinah shoal, it is found at the central part of shoal. Both the shoals are mutually different in condition of coral reef and coarse particulate sediment however common in the point that coral reef is always formed from the central part of upheaval toward offshore, inside which formation coarse calcareous sediment is formed. While the existence of calcareous mud prevents coral from growing and simultaneously lower reservoir rock in form condition. 26 figs.

  5. Working part-time: achieving a successful 'work-life' balance?

    Science.gov (United States)

    Warren, Tracey

    2004-03-01

    The role of part-time employment in the balancing of women's employment and family lives has generated an immense literature. Using data on women working part-time and full-time in different level occupations in the British Household Panel Survey, this paper argues that it is now vital to move these balancing debates on from their location within work-family rhetoric and to re-position the study of women's working time in broader work-life discussions. Work-family debates tend to neglect a number of key domains that women balance in their lives, in addition to family and employment, including their financial security and their leisure. The paper shows that examining the financial situations and the leisure lives of female part-timers in lower level jobs reveals a less positive picture of their 'life balancing' than is portrayed in much work-family literature. Instead, they emerged as the least financially secure employees and, linked to this, less satisfied with their social lives too. It is concluded that since the work-life system is multi- and not just two-dimensional, it is important to examine how all life domains interrelate with each other. In this way, we would be in a better position to begin to assess all the benefits and disadvantages associated with working part-time and with other work-life balancing strategies.

  6. Balancing carbon sequestration and GHG emissions in a constructed wetland

    NARCIS (Netherlands)

    Klein, de J.J.M.; Werf, van der A.K.

    2014-01-01

    In many countries wetlands are constructed or restored for removing nutrients from surface water. At the same time vegetated wetlands can act as carbon sinks when CO2 is sequestered in biomass. However, it is well known that wetlands also produce substantial amounts of greenhouse gasses CH4 and N2O.

  7. Carbon balance of CO2-EOR for NCNO classification

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Lopez, Vanessa [The University of Texas at Austin; Gil-Egui, Ramon; Gonzalez-Nicolas, Ana; Hovorka, Susan D

    2017-03-18

    The question of whether carbon dioxide enhanced oil recovery (CO2-EOR) constitutes a valid alternative for greenhouse gas emission reduction has been frequently asked by the general public and environmental sectors. Through this technology, operational since 1972, oil production is enhanced by injecting CO2 into depleted oil reservoirs in order displace the residual oil toward production wells in a solvent/miscible process. For decades, the CO2 utilized for EOR has been most commonly sourced from natural CO2 accumulations. More recently, a few projects have emerged where anthropogenic CO2 (A-CO2) is captured at an industrial facility, transported to a depleted oil field, and utilized for EOR. If carbon geologic storage is one of the project objectives, all the CO2 injected into the oil field for EOR could technically be stored in the formation. Even though the CO2 is being prevented from entering the atmosphere, and permanently stored away in a secured geologic formation, a question arises as to whether the total CO2 volumes stored in order to produce the incremental oil through EOR are larger than the CO2 emitted throughout the entire CO2-EOR process, including the capture facility, the EOR site, and the refining and burning of the end product. We intend to answer some of these questions through a DOE-NETL funded study titled “Carbon Life Cycle Analysis of CO2-EOR for Net Carbon Negative Oil (NCNO) Classification”. NCNO is defined as oil whose carbon emissions to the atmosphere, when burned or otherwise used, are less than the amount of carbon permanently stored in the reservoir in order to produce the oil. In this paper, we focus on the EOR site in what is referred to as a gate-to-gate system, but are inclusive of the burning of the refined product, as this end member is explicitly stated in the definition of NCNO. Finally, we use Cranfield, Mississippi, as a case study and come to the conclusion that the incremental oil produced is net carbon negative.

  8. Carbon balance and water use efficiency of frequently cut Lolium perenne L. swards at elevated carbon dioxide

    NARCIS (Netherlands)

    Schapendonk, A.H.C.M.; Dijkstra, P.; Groenwold, J.; Pot, C.S.; Geijn, van de S.C.

    1997-01-01

    The impact of doubled atmospheric [CO2] on the carbon balance of regularly cut Lolium perenne L. swards was studied for two years under semi-field conditions in the Wageningen Rhizolab. CO2 and H2O vapour exchange rates of the swards were measured continuously for two years in transparent

  9. Carbon balance of renovated grasslands: input- or output-driven?

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Osborne, Bruce; Lanigan, Gary

    2015-04-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. In permanent temperate grasslands, biomass production and sward quality can deteriorate over time and periodic renovation activities, involving soil tillage and reseeding, are commonly carried out to halt this decline. Long-term cultivation of agricultural land has been associated with soil aggregate degradation and reduced soil carbon storage. However, the impact of these single tillage disturbances on C cycling in grasslands is less clear. This study evaluated gaseous and dissolved organic carbon (DOC) losses following a single tillage event by subjecting grassland lysimeters with contrasting soil drainage characteristics to simulated conventional inversion or minimum tillage. Field-scale CO2 emissions after conventional tillage were also quantified and empirically modelled over short- and medium-term timeframes to delineate the ecosystem response to environmental variables. Soil moisture was the limiting determinant of ecosystem carbon release following conventional tillage. Freshly-tilled soils were associated with reduced water retention and increased sensitivity to soil moisture, which was particularly pronounced following rewetting events. Significantly elevated but ephemeral CO2 effluxes were detected in the hours following inversion ploughing, however tillage disturbance did not generate significantly enhanced C emission rates in the medium term. Equally, DOC losses were not significantly amplified by conventional tillage compared with conservative minimum tillage and were predominantly controlled by soil drainage across tillage regimes. Our results suggest that a net ecosystem source of 120 to 210 g C m-2 over an approximately two-month period was most likely a consequence of reduced productivity and C input rather than enhanced soil CO2

  10. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease

    Science.gov (United States)

    Hill, Kathleen M.; Martin, Berdine R.; Wastney, Meryl; McCabe, George P.; Moe, Sharon M.; Weaver, Connie M.; Peacock, Munro

    2014-01-01

    Chronic kidney disease (CKD) patients are given calcium carbonate to bind dietary phosphorus and reduce phosphorus retention, and to prevent negative calcium balance. Data are limited on calcium and phosphorus balance in CKD to support this. The aim of this study was to determine calcium and phosphorus balance and calcium kinetics with and without calcium carbonate in CKD patients. Eight stage 3/4 CKD patients, eGFR 36 mL/min, participated in two 3-week balances in a randomized placebo-controlled cross-over study of calcium carbonate (1500 mg/d calcium). Calcium and phosphorus balance were determined on a controlled diet. Oral and intravenous 45calcium with blood sampling and urine and fecal collections were used for calcium kinetics. Fasting blood and urine were collected at baseline and end of each week of each balance period for biochemical analyses. Results showed that patients were in neutral calcium and phosphorus balance while on placebo. Calcium carbonate produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance suggesting tissue deposition. Fasting biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. If they can be extrapolated to effects of chronic therapy, these data caution against the use of calcium carbonate as a phosphate binder. PMID:23254903

  11. The energy balance experiment EBEX-2000. Part III: Behaviour and quality of the radiation measurements

    NARCIS (Netherlands)

    Kohsiek, W.; Liebethal, C.; Foken, T.; Vogt, R.; Oncley, S.P.; Bernhofer, C.; Debruin, H.A.R.

    2007-01-01

    An important part of the Energy Balance Experiment (EBEX-2000) was the measurement of the net radiation and its components. Since the terrain, an irrigated cotton field, could not be considered homogeneous, radiation measurements were made at nine sites using a variety of radiation instruments,

  12. BALANCING ON THE BORDERLINE OF EARLY AFFECT-CONFUSION - PART 2 OF A CASE STUDY TRILOGY

    Directory of Open Access Journals (Sweden)

    Richard G. Erskine

    2013-05-01

    Full Text Available Part 2 of a case study trilogy on early affect-confusion describes the psychotherapy relationship between an angry/helpless client and the psychotherapist’s skill in balancing the “borderline” between behavioral management and affect attunement, historical inquiry and normalization, validation and shame. The therapeutic use of bifurcated questions and juxtaposition reactions is illustrated.

  13. Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States

    International Nuclear Information System (INIS)

    Zhang Chi; Tian Hanqin; Chen, Guangsheng; Chappelka, Arthur; Xu Xiaofeng; Ren Wei; Hui Dafeng; Liu Mingliang; Lu Chaoqun; Pan, Shufen; Lockaby, Graeme

    2012-01-01

    Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 10 15 ) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance. - Highlights: ► A series of spatial and temporal urban/developed land maps were generated. ► Urbanization effects on regional carbon dynamics were studied with a process-based Dynamic Land Ecosystem Model (DLEM). ► Carbon storage of urban/developed land was comparable to that stored in cropland and shrubland in the Southern United States. ► Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. ► Urbanization resulted in carbon emission, but established urban areas may gradually accumulate carbon over time. - Urbanization has resulted in carbon release to the atmosphere, but established urban areas may gradually accumulate carbon over time.

  14. Updated estimate of carbon balance on Russian territory

    Energy Technology Data Exchange (ETDEWEB)

    Kurganova, I. N.; Kudeyarov, V. N.; Gerenyu, V. O. Lopes de (Institute of Physicochemical and Biological Problems in Soil Science, RAS, Pushchino (Russian Federation)), e-mail: ikurg@mail.ru

    2010-11-15

    The land use system in Russia changed considerably after 1990: 30.2 million ha of croplands were abandoned. Based on the own field investigations that were carried out in abandoned lands of different age (Luvic Phaeozems, deciduous forest zone; Moscow region, 54 deg 50' N, 37 deg 37' E), it has been shown that after 4.5 yr of abandonment, the former croplands acted as a stable sink of CO{sub 2}. The net ecosystem production (NEP) in the post-agrogenic ecosystems averaged 245 +- 73gCm-2 yr-1 for the first 15 yr after land use change that corresponds to an estimated 74 +- 22 Tg C yr-1 for the total area of abandoned lands in Russian Federation. Currently, the Russian territory acts as an absolute sink of atmospheric CO{sub 2} at a rate about 0.90 Pg C yr-1. Using three different approaches, it was demonstrated that after 1990, the carbon sequestration in Russian soils (0.20 cm layer) has averaged 34 +- 2.2 Tg C yr-1. This soil C forms net biome production (NBP) where carbon lifetime is much longer than in 'Kyoto forests'. Thus, the post-agrogenic ecosystems in Russia provide with the additional CO{sub 2} sink in NEP and NBP that could annually compensate about 25% of the current fossil fuel emissions in the Russian Federation

  15. Carbon and nitrogen balances for six shrublands across Europe

    NARCIS (Netherlands)

    Beier, C.; Emmett, B.A.; Tietema, A.; Schmidt, I.K.; Penuelas, J.; Lang, E.K.; Duce, P.; Angelis, de P.; Gorissen, A.; Estiarte, M.; Dato, de G.D.; Sowerby, A.; Kroel-Dulay, G.; Lellei-Kovacs, E.; Kull, O.; Mand, P.; Petersen, H.; Gjelstrup, P.; Spano, D.

    2009-01-01

    Shrublands constitute significant and important parts of European landscapes providing a large number of important ecosystem services. Biogeochemical cycles in these ecosystems have gained little attention relative to forests and grassland systems, but data on such cycles are required for developing

  16. Influence of spring phenology on seasonal and annual carbon balance in two contrasting New England forests

    Science.gov (United States)

    Andrew D. Richardson; David Y. Hollinger; D. Bryan Dail; John T. Lee; J. William Munger; John O' Keefe

    2009-01-01

    Spring phenology is thought to exert a major influence on the carbon (C) balance of temperate and boreal ecosystems. We investigated this hypothesis using four spring onset phenological indicators in conjunction with surface-atmosphere CO2 exchange data from the conifer-dominated Howland Forest and deciduous-dominated Harvard Forest AmeriFlux...

  17. Direct and indirect effects of fires on the carbon balance of tropical forest ecosystems (Invited)

    Science.gov (United States)

    Randerson, J. T.; Tosca, M. G.; Ward, D. S.; Kasibhatla, P. S.; Mahowald, N. M.; Hess, P. G.

    2013-12-01

    Fires influence the carbon budget of tropical forests directly because they account for a significant component of net emissions from deforestation and forest degradation. They also have indirect effects on nearby intact forests by modifying regional climate, atmospheric composition, and patterns of nutrient deposition. These latter pathways are not well understood and are often ignored in climate mitigation efforts such as the United Nations Program on Reducing Emissions from Deforestation and forest Degradation (REDD+). Here we used the Community Atmosphere Model (CAM5) and the Global Fire Emissions Database (GFED3) to quantify the impacts of fire-emitted aerosols on the productivity of tropical forests. Across the tropical forest biome, fire-emitted aerosols reduced surface temperatures and increased the diffuse solar insolation fraction. These changes in surface meteorology increased gross primary production (GPP) in the Community Land Model. However, these drivers were more than offset in many regions by reductions in soil moisture and total solar radiation. The net effect of fire aerosols caused GPP to decrease by approximately 8% in equatorial Asia and 6% in the central Africa. In the Amazon, decreases in photosynthesis in the western part of the basin were nearly balanced by increases in the south and east. Using additional CAM5 and GEOS-Chem model simulations, we estimated fire contributions to surface concentrations of ozone. Using empirical relationships between ozone exposure and GPP from field studies and models, we estimated how tropical forest GPP was further modified by fire-induced ozone. Our results suggest that efforts to reduce the fire component of tropical land use fluxes may have sustainability benefits that extend beyond the balance sheet for greenhouse gases.

  18. Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance.

    Science.gov (United States)

    Turner, David P; Ritts, William D; Kennedy, Robert E; Gray, Andrew N; Yang, Zhiqiang

    2015-12-01

    Disturbance is a key influence on forest carbon dynamics, but the complexity of spatial and temporal patterns in forest disturbance makes it difficult to quantify their impacts on carbon flux over broad spatial domains. Here we used a time series of Landsat remote sensing images and a climate-driven carbon cycle process model to evaluate carbon fluxes at the ecoregion scale in western Oregon. Thirteen percent of total forest area in the West Cascades ecoregion was disturbed during the reference interval (1991-2010). The disturbance regime was dominated by harvesting (59 % of all area disturbed), with lower levels of fire (23 %), and pest/pathogen mortality (18 %). Ecoregion total Net Ecosystem Production was positive (a carbon sink) in all years, with greater carbon uptake in relatively cool years. Localized carbon source areas were associated with recent harvests and fire. Net Ecosystem Exchange (including direct fire emissions) showed greater interannual variation and became negative (a source) in the highest fire years. Net Ecosystem Carbon Balance (i.e. change in carbon stocks) was more positive on public that private forestland, because of a lower disturbance rate, and more positive in the decade of the 1990s than in the warmer and drier 2000s because of lower net ecosystem production and higher direct fire emissions in the 2000s. Despite recurrent disturbances, the West Cascades ecoregion has maintained a positive carbon balance in recent decades. The high degree of spatial and temporal resolution in these simulations permits improved attribution of regional carbon sources and sinks.

  19. When growth and photosynthesis don't match: implications for carbon balance models

    Science.gov (United States)

    Medlyn, B.; Mahmud, K.; Duursma, R.; Pfautsch, S.; Campany, C.

    2017-12-01

    Most models of terrestrial plant growth are based on the principle of carbon balance: that growth can be predicted from net uptake of carbon via photosynthesis. A key criticism leveled at these models by plant physiologists is that there are many circumstances in which plant growth appears to be independent of photosynthesis: for example, during the onset of drought, or with rising atmospheric CO2 concentration. A crucial problem for terrestrial carbon cycle models is to develop better representations of plant carbon balance when there is a mismatch between growth and photosynthesis. Here we present two studies providing insight into this mismatch. In the first, effects of root restriction on plant growth were examined by comparing Eucalyptus tereticornis seedlings growing in containers of varying sizes with freely-rooted seedlings. Root restriction caused a reduction in photosynthesis, but this reduction was insufficient to explain the even larger reduction observed in growth. We applied data assimilation to a simple carbon balance model to quantify the response of carbon balance as a whole in this experiment. We inferred that, in addition to photosynthesis, there are significant effects of root restriction on growth respiration, carbon allocation, and carbohydrate utilization. The second study was carried out at the EucFACE Free-Air CO2 Enrichment experiment. At this experiment, photosynthesis of the overstorey trees is increased with enriched CO2, but there is no significant effect on above-ground productivity. These mature trees have reached their maximum height but are at significant risk of canopy loss through disturbance, and we hypothesized that additional carbon taken up through photosynthesis is preferentially allocated to storage rather than growth. We tested this hypothesis by measuring stemwood non-structural carbohydrates (NSC) during a psyllid outbreak that completely defoliated the canopy in 2015. There was a significant drawdown of NSC during

  20. Carbon in the Former Soviet Union: The Current Balance

    Science.gov (United States)

    Woodwell, G. M.; Stone, T. A.; Houghton, R. A.

    1997-01-01

    senior scientist (mensuration) for the Soviet Committee on Forests, now a scholar at the International Institute of Applied Systems Analysis (IIASA), Vienna, has provided abundant contributions from the data available to him and from his experience. Forest stand carbon is concentrated in the Russian Far East (i.e. Primorski Kray), Central-Southern Siberia and European Russia But, soil carbon can be 10 times forest stand C. Our efforts in mapping the area and changes in area (as well as the internal structure) of forests have made major contributions to our joint understanding of the scale and status of these forests. To realize the importance of this contribution one needs only to recognize that any large scale Soviet-era maps of the area did not include latitude and longitude. Even today, there is great reluctance to provide these data, the basis of any GIS.

  1. Intensive biomass harvesting in forests - what about the carbon balance?

    International Nuclear Information System (INIS)

    Berg, Bjoern; Johansson, Maj-Britt

    1998-08-01

    The use of biofuels is considered to be CO 2 -neutral. This means that the use of forest biomass for fuel does not add more CO 2 to the atmosphere than what has been taken up over a stand age by photosynthesis. However, the biomass that may be harvested only contains part of the CO 2 immobilized through fixation during the growth of the forest stand. A fraction of the produced biomass will always decompose on and in the soil, in part producing humus and in part CO 2 . To this fraction belongs the litter formed during the period of stand growth, e.g. the annual foliar litterfall. The decomposition of both foliar litter and green needles have been shown to follow an asymptotic function, meaning that the decomposition approaches a limit value. This means that recalcitrant remains are left. The decomposition of felling residues have been assumed to follow the same function. The obvious question is how the amount of humus is affected by removal of felling residues. In an investigation of humus storage in five stands of Norway spruce in south Sweden limit values were estimated for the decomposition of local spruce needle litter giving a variation from 63 to 85 per cent. With the use of these limit values and the amount of litterfall the accumulation of humus was estimated. These calculations showed that there is a growth of the humus layer in the period of stand growth. The rate of humus accumulation varied among the stands and on the average a theoretical humus accumulation of about 42 tons per hectare was estimated for a stand age of 60 years. This amount of already accumulated humus is not affected by harvests of remains from thinnings or clearcuts. If, on the other hand the felling residues are not removed that means that the amount of humus should increase. Experiments with soil scarification showed that for litter buried under plowed-up mineral soil the decomposition went further than in soil not scarified. The estimated limit value was on the average about 40 per

  2. Incorrectly Interpreting the Carbon Mass Balance Technique Leads to Biased Emissions Estimates from Global Vegetation Fires

    Science.gov (United States)

    Surawski, N. C.; Sullivan, A. L.; Roxburgh, S. H.; Meyer, M.; Polglase, P. J.

    2016-12-01

    Vegetation fires are a complex phenomenon and have a range of global impacts including influences on climate. Even though fire is a necessary disturbance for the maintenance of some ecosystems, a range of anthropogenically deleterious consequences are associated with it, such as damage to assets and infrastructure, loss of life, as well as degradation to air quality leading to negative impacts on human health. Estimating carbon emissions from fire relies on a carbon mass balance technique which has evolved with two different interpretations in the fire emissions community. Databases reporting global fire emissions estimates use an approach based on `consumed biomass' which is an approximation to the biogeochemically correct `burnt carbon' approach. Disagreement between the two methods occurs because the `consumed biomass' accounting technique assumes that all burnt carbon is volatilized and emitted. By undertaking a global review of the fraction of burnt carbon emitted to the atmosphere, we show that the `consumed biomass' accounting approach overestimates global carbon emissions by 4.0%, or 100 Teragrams, annually. The required correction is significant and represents 9% of the net global forest carbon sink estimated annually. To correctly partition burnt carbon between that emitted to the atmosphere and that remaining as a post-fire residue requires the post-burn carbon content to be estimated, which is quite often not undertaken in atmospheric emissions studies. To broaden our understanding of ecosystem carbon fluxes, it is recommended that the change in carbon content associated with burnt residues be accounted for. Apart from correctly partitioning burnt carbon between the emitted and residue pools, it enables an accounting approach which can assess the efficacy of fire management operations targeted at sequestering carbon from fire. These findings are particularly relevant for the second commitment period for the Kyoto protocol, since improved landscape fire

  3. Effects of experimental warming of air, soil and permafrost on carbon balance in Alaskan tundra

    Science.gov (United States)

    S.M. Natali; E.A.G. Schuur; C. Trucco; C.E. Hicks Pries; K.G. Crummer; A.F. Baron Lopez

    2011-01-01

    The carbon (C) storage capacity of northern latitude ecosystems may diminish as warming air temperatures increase permafrost thaw and stimulate decomposition of previously frozen soil organic C. However, warming may also enhance plant growth so that photosynthetic carbon dioxide (C02) uptake may, in part, offset respiratory losses. To determine...

  4. Impacts of Human Induced Nitrogen Deposition on Ecosystem Carbon Sequestration and Water Balance in China

    Science.gov (United States)

    Sheng, M.; Yang, D.; Tang, J.; Lei, H.

    2017-12-01

    Enhanced plant biomass accumulation in response to elevated atmospheric CO2 concentration could dampen the future rate of increase in CO2 levels and associated climate warming. However, many experiments around the world reported that nitrogen availability could limit the sustainability of the ecosystems' response to elevated CO2. In the recent 20 years, atmospheric nitrogen deposition, primarily from fossil fuel combustion, has increased sharply about 25% in China and meanwhile, China has the highest carbon emission in the world, implying a large opportunity to increase vegetation greenness and ecosystem carbon sequestration. Moreover, the water balance of the ecosystem will also change. However, in the future, the trajectory of increasing nitrogen deposition from fossil fuel use is to be controlled by the government policy that shapes the energy and industrial structure. Therefore, the historical and future trajectories of nitrogen deposition are likely very different, and it is imperative to understand how changes in nitrogen deposition will impact the ecosystem carbon sequestration and water balance in China. We here use the Community Land Model (CLM 4.5) to analyze how the change of nitrogen deposition has influenced and will influence the ecosystem carbon and water cycle in China at a high spatial resolution (0.1 degree). We address the following questions: 1) what is the contribution of the nitrogen deposition on historical vegetation greenness? 2) How does the change of nitrogen deposition affect the carbon sequestration? 3) What is its influence to water balance? And 4) how different will be the influence of the nitrogen deposition on ecosystem carbon and water cycling in the future?

  5. The full annual carbon balance of a subtropical coniferous plantation is highly sensitive to autumn precipitation.

    Science.gov (United States)

    Xu, Mingjie; Wang, Huimin; Wen, Xuefa; Zhang, Tao; Di, Yuebao; Wang, Yidong; Wang, Jianlei; Cheng, Chuanpeng; Zhang, Wenjiang

    2017-08-30

    Deep understanding of the effects of precipitation on carbon budgets is essential to assess the carbon balance accurately and can help predict potential variation within the global change context. Therefore, we addressed this issue by analyzing twelve years (2003-2014) of observations of carbon fluxes and their corresponding temperature and precipitation data in a subtropical coniferous plantation at the Qianyanzhou (QYZ) site, southern China. During the observation years, this coniferous ecosystem experienced four cold springs whose effects on the carbon budgets were relatively clear based on previous studies. To unravel the effects of temperature and precipitation, the effects of autumn precipitation were examined by grouping the data into two pools based on whether the years experienced cold springs. The results indicated that precipitation in autumn can accelerate the gross primary productivity (GPP) of the following year. Meanwhile, divergent effects of precipitation on ecosystem respiration (Re) were found. Autumn precipitation was found to enhance Re in normal years but the same regulation was not found in the cold-spring years. These results suggested that for long-term predictions of carbon balance in global climate change projections, the effects of precipitation must be considered to better constrain the uncertainties associated with the estimation.

  6. Carbon and greenhouse gas balance of the FR-GRI crop site from 2005 to 2014

    Science.gov (United States)

    Loubet, Benjamin; Chammakhi, Manel; Mascher, Nicolas; Durand, Brigitte; Gueudet, Jean-Christophe; Decuq, Céline; Lecuyer, Vanessa; Laville, Patricia; Buysse, Pauline; Cellier, Pierre

    2017-04-01

    The carbon and greenhouse gas balance of the ICOS FR-GRI site from 2005 to 2014 is presented. The site is a wheat-barley-maize rotation with the introduction of oil-seed rape in 2012. The site receives large amounts of organic fertilization, but is shown to be a strong source of carbon to the atmosphere, especially due to the increase in the exportations of residues during the period. The exportations have increased from around 4 to around 8 t C ha-1 year-1 over the period on average except for maize for which it remained constant. In the meantime the carbon importations have increased from around 1 to around 2 t C ha-1 year-1 during the same period. Overall the field was losing around 2 t C ha-1 year-1 over the whole period but largely driven by last years (2012-2014). This would represent 17% loss of the soil carbon content in the 0-60 cm in the 2005-2014 period. The discussion focuses on explanations of these losses and possible drawbacks in the methodology. The effect of the winter intermediate crops on the carbon balance is also discussed.

  7. Who's got the balance? A study of satisfaction with the work-family balance among part-time service sector employees in five western European countries

    NARCIS (Netherlands)

    Beham, Barbara; Prag, Patrick; Drobnic, Sonja

    2012-01-01

    Working part-time is frequently considered a viable strategy for employees to better combine work and non-work responsibilities. The present study examines differences in satisfaction with work-family balance (SWFB) among professional and non-professional part-time service sector employees in five

  8. Atmospheric CO2 measurements reveal strong drought sensitivity of Amazonian carbon balance

    Science.gov (United States)

    Miller, J. B.; Gatti, L.; Gloor, M.; Doughty, C.; Malhi, Y.; Domingues, L. G.; Basso, L. S.; Martinewski, A.; Correia, C.; Borges, V.; Freitas, S. R.; Braz, R.; Anderson, L.; Rocha, H.; Grace, J.; Phillips, O.; Lloyd, J.

    2013-12-01

    Potential feedbacks between land carbon pools and climate are one of the largest sources of uncertainty for predicting future global climate, but estimates of their sensitivity to climate anomalies in the tropics and determination of underlying mechanisms are either incomplete or strongly model-based. Amazonia alone stores ~150-200 Pg of labile carbon, and has experienced an increasing trend in temperature and extreme floods and droughts over the last two decades. Here we report the first Amazon Basin-wide seasonal and annual carbon balances based on tropospheric greenhouse gas sampling, during an anomalously dry and a wet year, 2010 and 2011, providing the first whole-system assessment of sensitivity to such conditions. During 2010, the Amazon Basin lost 0.5×0.2 PgCyr-1 while in 2011 it was approximately carbon neutral (0.06×0.1 PgCyr-1). Carbon loss via fire was 0.5×0.1 PgCyr-1 in 2010 and 0.3×0.1 PgCyr-1 in 2011, as derived from Basin-wide carbon monoxide (CO) enhancements. Subtracting fire emissions from total carbon flux to derive Basin net biome exchange (NBE) reveals that in 2010 the non-fire regions of the Basin were carbon neutral; in 2011 they were a net carbon sink of -0.3×0.1 PgC yr-1, roughly consistent with a three-decade long intact-forest biomass sink of ~ -0.5×0.3 PgCyr-1 estimated from forest censuses. Altogether, our results suggest that if the recent trend of precipitation extremes persists, the Amazon region may become an increasing carbon source as a result of both emissions from fires and suppression of NBE by drought.

  9. Carbon balance studies of glucose metabolism in rat cerebral cortical synaptosomes

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, U; Brand, K

    1982-07-01

    Synaptosomes were isolated from rat cerebral cortex and incubated with (U-/sup 14/C)-, (1-/sup 14/C)- or (6-/sup 14/C)glucose. Glucose utilization and the metabolic partitioning of glucose carbon in products were determined by isotopic methods. From the data obtained a carbon balance was constructed, showing lactate to be the main product of glucose metabolism, followed by CO/sup 2/, amino acids and pyruvate. Measuring the release of /sup 14/CO/sup 2/ from glucose labelled in three different positions allowed the construction of a flow diagram of glucose carbon atoms in synaptosomes, which provides information about the contribution of the various pathways of glucose metabolism. Some 2% of glucose utilized was calculated to be degraded via the pentose phosphate pathway. Addition of chlorpromazine, imipramine or haloperidol at concentrations of 10(-5) M reduced glucose utilisation by 30% without changing the distribution pattern of radioactivity in the various products.

  10. Towards an integrated, multiple constraint approach. Assessing the regional carbon balance

    International Nuclear Information System (INIS)

    Kruijt, B.; Dolman, A.J.; Lloyd, J.; Ehleringer, J.; Raupach, M.; Finnigan, J.

    2001-01-01

    Full carbon accounting for regions as a whole, considering all fluxes and transports, is ultimately the only real hope if we are to manage global CO2 emissions. Many methods exist to estimate parts of the carbon budget, but none is yet available to measure carbon fluxes directly at regional scales. Atmospheric Boundary-Layer budgeting methods do have this potential. In the winter of 2000, an international workshop was held in Gubbio, Italy, to discuss ways to advance from the pilot experiments that have been carried out on these methods. First, the meeting helped to advance the methodology and clarify its objectives, requirements and merits. But more importantly, the outcome of the meeting was that atmospheric budget methods should be part of an integrative approach, in which data and model results of very different kinds and from very different scales all provide constraints for estimating the net carbon exchange of a region. Several international projects are now operating to achieve this goal

  11. The response of dissolved organic carbon (DOC) and the ecosystem carbon balance to experimental drought in a temperate shrubland

    DEFF Research Database (Denmark)

    Sowerby, A.; Emmett, B.A.; Williams, D.

    2010-01-01

    in northeast Wales, we have carried out an annual drought treatment for 8 years, reducing levels of annual rainfall by 23% on average (1999–2007) through the use of automated roofs, which prevent rain falling on experimental plots between June and September annually. Following 5 years of repeated summer...... drainage of water from the drought-treated soils resulted in an overall decrease of 9% in total DOC export. Calculating the carbon (C) balance for the below-ground component of the ecosystem reveals that DOC represents 3% of gross C export. Previous studies at the site have demonstrated large increases...... in soil respiration resulting from the repeated drought treatment. By including data presented here with other C fluxes and pool measurements from the site, we demonstrate that soil carbon is accumulating by 126 g C m−2 year−1 in the control plots, but decreasing by 18 g C m2 year−1 in the drought plots...

  12. CO2 and Carbon Balance of an Intensively Grazed Temperate Pasture: Response to Cultivation

    Science.gov (United States)

    Rutledge, S.; Mudge, P. L.; Wallace, D.; Campbell, D.; Wall, A.; Hosking, C. L.; Schipper, L. A.

    2012-12-01

    Recent soil resampling studies have shown that soils on flat land used for intensive dairy farming in New Zealand have lost large amounts of carbon (~1 t C ha-1y-1) over the past few decades, and the causes of these losses are poorly understood. One of the management practices potentially contributing to the C losses from these dairy soils is the periodic cultivation commonly associated with pasture renewal or the rotation through summer or winter crops. Here we report the results of three experiments aimed at quantifying the effect of cultivation as part of pasture renewal on the CO2 and C balances of permanent pastures. In the first experiment, the net ecosystem CO2 exchange (NEE) of an intensively grazed dairy pasture was measured before, during and after cultivation using eddy covariance (EC) from 2008 to 2011 at a dairy farm in the Waikato region on the North Island of New Zealand. The net ecosystem carbon balance (NECB) was determined by combining NEE data with measurements and estimates of other C imports (feed) and C exports (milk, methane, silage and leaching). The other two experiments took place on the same farm and monitored two different cultivation events in 2008. We made chamber measurements of soil CO2 losses between spraying and seedling emergence. One of the cultivations took place in summer 2008 during a drought, whereas the other took place in spring 2008 when soil water was not limiting. For the first two years of experiment 1 the site was under permanent pasture and it was a sink for both CO2 (1.6 and 2.3 t C ha-1y-1 for 2008 and 2009, respectively) and C (0.59 and 0.90 t C ha-1y-1 for 2008 and 2009, respectively), despite a severe drought in summer 2008 which had led to a loss of approximately 1.1 t C ha-1 as CO2 over the three summer months. Pasture renewal took place in March 2010 and CO2 losses during this event were approximately 1.7 t C ha-1. However, the site seemed to recover quickly and was a sink of CO2 at an annual time scale of

  13. Toward a consistency cross-check of eddy covariance flux-based and biometric estimates of ecosystem carbon balance

    NARCIS (Netherlands)

    Luyssaert, S.; Reichstein, M.; Schulze, E.D.; Janssens, I.A.; Law, B.E.; Papale, D.; Dragoni, D.; Goulden, M.L.; Granier, A.; Kutch, W.L.; Linder, S.; Matteucci, G.; Moors, E.J.; Munger, J.W.; Pilegaard, K.; Saunders, M.; Falge, E.M.

    2009-01-01

    Quantification of an ecosystem's carbon balance and its components is pivotal for understanding both ecosystem functioning and global cycling. Several methods are being applied in parallel to estimate the different components of the CO2 balance. However, different methods are subject to different

  14. Carbon and water balance of European croplands throughout the 20th century

    Science.gov (United States)

    Gervois, SéBastien; Ciais, Philippe; de Noblet-Ducoudré, Nathalie; Brisson, Nadine; Vuichard, Nicolas; Viovy, Nicolas

    2008-06-01

    We assessed the effects of rising atmospheric CO2, changing climate, and farmers' practice on the carbon and water balance of European croplands during the past century (1901-2000). The coupled vegetation-crop model ORCHIDEE-STICS is applied over western Europe for C3 crops (winter wheat) and for maize, with prescribed historical agricultural practice changes. Not surprisingly, the enormous crop yield increase observed in all European regions, 300-400% between 1950 and 2000, is found to be dominantly explained by improved practice and varieties selection, rather than by rising CO2 (explaining a ˜11% uniform increase in yield) and changing climate (no further change in yield on average, but causing a decrease of ˜19% in the southern Iberian Peninsula). Agricultural soil carbon stocks in Europe are modeled to have decreased between 1950 and 1970, and since then to have increased again. Thus, the current stocks only differ by 1 ± 6 tC ha-1 from their 1900 value. Compensating effects of increasing yields on the one hand (increasing stocks) and of higher harvest index values and ploughing on the other hand (decreasing stocks) occur. Each of these processes taken individually has the potential to strongly alter the croplands soil carbon balance in the model. Consequently, large uncertainties are associated to the estimated change in carbon stocks between 1901 and 2001, roughly ±6 tC ha-1 a-1. In our most realistic simulation, the current cropland carbon balance is a net sink of 0.16 ± 0.15 tC ha-1 a-1. The annual water balance of cropland soils is influenced by increasing crop water use efficiency, one third of which is caused by rising CO2. However, increasing water use efficiency occurred mainly in spring and winter, when water is not limiting for plant growth, whereas no strong savings of soil water are achieved in summer through elevated CO2. Overall, trends in cultivation practices have caused a 3 times larger increase of water use efficiency than rising CO2.

  15. Carbon sequestration capacity in a semiarid ecosystem: A carbon balance approach

    International Nuclear Information System (INIS)

    Almagro, M.; Lopez, J.; Boix-Fayos, C.; Albaladejo, J.; Martinez-Mena, M.

    2009-01-01

    Here, we used two C balance approaches to estimate total below ground C allocation (TBCA) in three representative land uses in a Mediterranean ecosystem (late-successional forest, abandoned agricultural field, rainfed olive grove). Our objectives were: 1) to asses the response of TBCA and its components to changes in land use; 2) to evaluate how soil water erosion and changes in C stored in roots, soil and litter layer altered our estimates of TBCA; 3) to determine annual net ecosystem productivity, and examine C allocation patterns at each land use. (Author) 4 refs.

  16. Measuring and modeling carbon balance in mountainous Northern Rocky mixed conifer forests

    Science.gov (United States)

    Hudiburg, T. W.; Berardi, D.; Stenzel, J.

    2016-12-01

    Drought and wildfire caused by changing precipitation patterns, increased temperatures, increased fuel loads, and decades of fire suppression are reducing forest carbon uptake from local to continental scales. This trend is especially widespread in Idaho and the intermountain west and has important implications for climate change and forest management options. Given the key role of forests in climate regulation, understanding forest response to drought and the feedbacks to the atmosphere is a key research and policy-relevant priority globally. As temperature, fire, and precipitation regimes continue to change and there is increased risk of forest mortality, measurements and modeling at temporal and spatial scales that are conducive to understanding the impacts and underlying mechanisms of carbon and nutrient cycling become critically important. Until recently, sub-daily measurements of ecosystem carbon balance have been limited in remote, mountainous terrain (e.g Northern Rocky mountain forests). Here, we combine new measurement technology and state-of-the-art ecosystem modeling to determine the impact of drought on the total carbon balance of a mature, mixed-conifer forest in Northern Idaho. Our findings indicate that drought had no impact on aboveground NPP, despite early growing season reductions in soil moisture and fine root biomass compared to non-drought years in the past. Modeled estimates of net ecosystem production (NEP) suggest that a simultaneous reduction in heterotrophic respiration increased the carbon sink for this forest. This has important implications for forest management, such as thinning where the objectives are to increase forest resilience to fire and drought, but may decrease NEP.

  17. Projecting future impacts of hurricanes on the carbon balance of eastern U.S. forests

    Science.gov (United States)

    Fisk, J. P.; Hurtt, G. C.; Chambers, J. Q.; Zeng, H.; Dolan, K.; Flanagan, S.; Rourke, O.; Negron Juarez, R. I.

    2011-12-01

    In U.S. Atlantic coastal areas, hurricanes are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial recent progress has been made to estimate the biomass loss and resulting carbon emissions caused by hurricanes impacting the U.S. Additionally, efforts to evaluate the net effects of hurricanes on the regional carbon balance have demonstrated the importance of viewing large disturbance events in the broader context of recovery from a mosaic of past events. Viewed over sufficiently long time scales and large spatial scales, regrowth from previous storms may largely offset new emissions; however, changes in number, strength or spatial distribution of extreme disturbance events will result in changes to the equilibrium state of the ecosystem and have the potential to result in a lasting carbon source or sink. Many recent studies have linked climate change to changes in the frequency and intensity of hurricanes. In this study, we use a mechanistic ecosystem model, the Ecosystem Demography (ED) model, driven by scenarios of future hurricane activity based on historic activity and future climate projections, to evaluate how changes in hurricane frequency, intensity and spatial distribution could affect regional carbon storage and flux over the coming century. We find a non-linear response where increased storm activity reduces standing biomass stocks reducing the impacts of future events. This effect is highly dependent on the spatial pattern and repeat interval of future hurricane activity. Developing this kind of predictive modeling capability that tracks disturbance events and recovery is key to our understanding and ability to predict the carbon balance of forests.

  18. The full annual carbon balance of Eurasian boreal forests is highly sensitive to precipitation

    Science.gov (United States)

    Öquist, Mats; Bishop, Kevin; Grelle, Achim; Klemedtsson, Leif; Köhler, Stephan; Laudon, Hjalmar; Lindroth, Anders; Ottosson Löfvenius, Mikaell; Wallin, Marcus; Nilsson, Mats

    2013-04-01

    Boreal forest biomes are identified as one of the major sinks for anthropogenic atmospheric CO2 and are also predicted to be particularly sensitive to climate change. Recent advances in understanding the carbon balance of these biomes stems mainly from eddy-covariance measurements of the net ecosystem exchange (NEE). However, NEE includes only the vertical CO2 exchange driven by photosynthesis and ecosystem respiration. A full net ecosystem carbon balance (NECB) also requires inclusion of lateral carbon export (LCE) through catchment discharge. Currently LCE is often regarded as negligible for the NECB of boreal forest ecosystems of the northern hemisphere, commonly corresponding to ~5% of annual NEE. Here we use long term (13 year) data showing that annual LCE and NEE are strongly correlated (p=0.003); years with low C sequestration by the forest coincide with years when lateral C loss is high. The fraction of NEE lost annually through LCE varied markedly from solar radiation caused by clouds. The dual effect of precipitation implies that both the observed and the predicted increases in annual precipitation at high latitudes may reduce NECB in boreal forest ecosystems. Based on regional scaling of hydrological discharge and observed spatio-temporal variations in forest NEE we conclude that our finding is relevant for large areas of the boreal Eurasian landscape.

  19. Variability in energy and carbon dioxide balances of wood and concrete building materials

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Leif; Sathre, Roger [Ecotechnology, Mid Sweden University, SE-831 25 OEstersund (Sweden)

    2006-07-15

    A variety of factors affect the energy and CO{sub 2} balances of building materials over their lifecycle. Previous studies have shown that the use of wood for construction generally results in lower energy use and CO{sub 2} emission than does the use of concrete. To determine the uncertainties of this generality, we studied the changes in energy and CO{sub 2} balances caused by variation of key parameters in the manufacture and use of the materials comprising a wood- and a concrete-framed building. Parameters considered were clinker production efficiency, blending of cement, crushing of aggregate, recycling of steel, lumber drying efficiency, material transportation distance, carbon intensity of fossil fuel, recovery of logging, sawmill, construction and demolition residues for biofuel, and growth and exploitation of surplus forest not needed for wood material production. We found the materials of the wood-framed building had lower energy and CO{sub 2} balances than those of the concrete-framed building in all cases but one. Recovery of demolition and wood processing residues for use in place of fossil fuels contributed most significantly to the lower energy and CO{sub 2} balances of wood-framed building materials. We conclude that the use of wood building material instead of concrete, coupled with greater integration of wood by-products into energy systems, would be an effective means of reducing fossil fuel use and net CO{sub 2} emission to the atmosphere. (author)

  20. Variability in energy and carbon dioxide balances of wood and concrete building materials

    International Nuclear Information System (INIS)

    Gustavsson, Leif; Sathre, Roger

    2006-01-01

    A variety of factors affect the energy and CO 2 balances of building materials over their lifecycle. Previous studies have shown that the use of wood for construction generally results in lower energy use and CO 2 emission than does the use of concrete. To determine the uncertainties of this generality, we studied the changes in energy and CO 2 balances caused by variation of key parameters in the manufacture and use of the materials comprising a wood- and a concrete-framed building. Parameters considered were clinker production efficiency, blending of cement, crushing of aggregate, recycling of steel, lumber drying efficiency, material transportation distance, carbon intensity of fossil fuel, recovery of logging, sawmill, construction and demolition residues for biofuel, and growth and exploitation of surplus forest not needed for wood material production. We found the materials of the wood-framed building had lower energy and CO 2 balances than those of the concrete-framed building in all cases but one. Recovery of demolition and wood processing residues for use in place of fossil fuels contributed most significantly to the lower energy and CO 2 balances of wood-framed building materials. We conclude that the use of wood building material instead of concrete, coupled with greater integration of wood by-products into energy systems, would be an effective means of reducing fossil fuel use and net CO 2 emission to the atmosphere. (author)

  1. Net ecosystem exchange of CO2 and carbon balance for eight temperate organic soils under agricultural management

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Görres, C.-M.; Hoffmann, Carl Christian

    2012-01-01

    This study presents the first annual estimates of net ecosystem exchange (NEE) of CO2 and net ecosystem carbon balances (NECB) of contrasting Danish agricultural peatlands. Studies were done at eight sites representing permanent grasslands (PG) and rotational (RT) arable soils cropped to barley......, potato or forage grasses in three geo-regional settings. Using an advanced flux-chamber technique, NEE was derived from modelling of ecosystem respiration (ER) and gross primary production (GPP) with temperature and photosynthetically active radiation as driving variables. At PG (n = 3) and RT (n = 5......) sites, NEE (mean ± standard error, SE) was 5.1 ± 0.9 and 8.6 ± 2.0 Mg C ha−1 yr−1, respectively, but with the overall lowest value observed for potato cropping (3.5 Mg C ha−1 yr−1). This was partly attributed to a short-duration vegetation period and drying of the soil especially in potato ridges. NECB...

  2. Effect of forest drainage on the carbon balance of a mire: a case study

    International Nuclear Information System (INIS)

    Laine, J.; Minkkinen, K.

    1996-01-01

    Natural mires generally act as sinks for CO 2 and are sources of CH 4 for the atmosphere. However, drainage may transform these ecosystems into net sources of CO 2 , but the increase in growth of the tree stand and consequent fixation of carbon after drainage may be expected to have a compensating effect. The post-drainage change in the peat carbon stores was determined using a method based on the bulk density and carbon content profiles measured along a transect running from the undrained part to the drained part of the mire. The difference between the undrained and drained peat carbon stores, averaged over the 30 yr period after drainage, indicated that the accumulation of carbon had been 35 g C m -2 yr -1 greater in the undrained site. As the long-term accumulation rate of the undrained site had been 21 g C m -2 yr -1 , the drained part had lost 14 g C m -2 yr -1 from the pre-drainage carbon store. Total accumulated biomass in the tree stand was estimated from stem wood development using the growth and yield tables for this site type. The stem wood volumes were transformed into total biomass values using published stem-volume/total-biomass ratios. If no harvesting operations were to occur during the first 300 yrs, the tree stand would produce an average carbon store of approximately 11 kg C m -2 . The application of a standard thinning regime would reduce this storage by ca 50%. Expressed as an average over 300 yrs, drainage increased the total carbon store of the mire if no tree harvesting was done and the store remained unchanged if standard harvesting procedures were used. 24 refs, 3 figs

  3. Incorporating Ecosystem Processes Controlling Carbon Balance Into Models of Coupled Human-Natural Systems

    Science.gov (United States)

    Currie, W.; Brown, D. G.; Brunner, A.; Fouladbash, L.; Hadzick, Z.; Hutchins, M.; Kiger, S. E.; Makino, Y.; Nassauer, J. I.; Robinson, D. T.; Riolo, R. L.; Sun, S.

    2012-12-01

    A key element in the study of coupled human-natural systems is the interactions of human populations with vegetation and soils. In human-dominated landscapes, vegetation production and change results from a combination of ecological processes and human decision-making and behavior. Vegetation is often dramatically altered, whether to produce food for humans and livestock, to harvest fiber for construction and other materials, to harvest fuel wood or feedstock for biofuels, or simply for cultural preferences as in the case of residential lawns with sparse trees in the exurban landscape. This alteration of vegetation and its management has a substantial impact on the landscape carbon balance. Models can be used to simulate scenarios in human-natural systems and to examine the integration of processes that determine future trajectories of carbon balance. However, most models of human-natural systems include little integration of the human alteration of vegetation with the ecosystem processes that regulate carbon balance. Here we illustrate a few case studies of pilot-study models that strive for this integration from our research across various types of landscapes. We focus greater detail on a fully developed research model linked to a field study of vegetation and soils in the exurban residential landscape of Southeastern Michigan, USA. The field study characterized vegetation and soil carbon storage in 5 types of ecological zones. Field-observed carbon storage in the vegetation in these zones ranged widely, from 150 g C/m2 in turfgrass zones, to 6,000 g C/m2 in zones defined as turfgrass with sparse woody vegetation, to 16,000 g C/m2 in a zone defined as dense trees and shrubs. Use of these zones facilitated the scaling of carbon pools to the landscape, where the areal mixtures of zone types had a significant impact on landscape C storage. Use of these zones also facilitated the use of the ecosystem process model Biome-BGC to simulate C trajectories and also

  4. A comparative assessment of the energy and carbon balance of utilizing straw

    International Nuclear Information System (INIS)

    Horne, R.E.; Mortimer, N.D.; Hetherington, Robert; Grant, J.F.

    1996-01-01

    There has been a recent growth of interest in the potential for using straw as an energy source to generate electricity and/or heat. The energy balance of this process is important as a measure of the sustainability of such an activity, while the CO 2 emitted and that saved by offsetting the need to produce energy by other means are also important, given the U.K.'s obligations to reduce CO 2 emissions. An existing methodology is adopted to calculate estimates of primary energy inputs and CO 2 outputs. Results of calculations are presented and considered in the context of their implications for potential uses of straw represented by four scenarios. Conclusions are drawn concerning the contributions to the energy and carbon balances of using straw as a fuel and recommendations are made for further work. (author)

  5. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. CO2 and CH4 fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    International Nuclear Information System (INIS)

    Alm, J.

    1997-01-01

    Release of CO 2 from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO 2 efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO 2 and CH 4 (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO 2 under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH 4 release was studied. The Holocene history of CO 2 sequestration and CH 4 emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO 2 release from peat. A drought lasting from late May to July caused a 90 g C m 2 net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO 2 release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m -2 a -1 in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m -2 a -1 for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants contributed to the total peat CO 2 efflux by 10-40 % as root respiration

  7. Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO2 and chlorophyll fluorescence from GOSAT

    NARCIS (Netherlands)

    Parazoo, Nicholas C.; Bowman, Kevin; Frankenberg, Christian; Lee, Jung-Eun; Fisher, Joshua B.; Worden, John; Jones, Dylan B. A.; Berry, Joseph; Collatz, G. James; Baker, Ian T.; Jung, Martin; Liu, Junjie; Osterman, Gregory; O'Dell, Chris; Sparks, Athena; Butz, Andre; Guerlet, Sandrine; Yoshida, Yukio; Chen, Huilin; Gerbig, Christoph

    2013-01-01

    Amazon forests exert a major influence on the global carbon cycle, but quantifying the impact is complicated by diverse landscapes and sparse data. Here we examine seasonal carbon balance in southern Amazonia using new measurements of column-averaged dry air mole fraction of CO2 (XCO2) and solar

  8. Particle balance analysis on carbon sheet pump applied to the GAMMA10 tandem mirror plasmas

    International Nuclear Information System (INIS)

    Ishimoto, Yuki; Nakashima, Yousuke; Ishinuki, Eiichi; Kobayashi, Shinji; Yoshikawa, Masayuki; Tamano, Teruo; Yatsu, Kiyoshi; Sagara, Akio

    2000-01-01

    Carbon Sheet Pump (CSP) is expected as a tool for reduction of hydrogen recycling. In this paper, particle balance in the CSP is described. The pumping efficiencies estimated from the time evolution of hydrogen pressures during plasma discharges and those estimated from the thermal desorption experiments have no remarkable difference between the cases of 30degC and 200degC within experimental errors. In cases that CSP is used in actual plasma conditions, we established a method which reduces adsorbed gases on the CSP surface with sustaining a sufficient pumping efficiency by continuously heating CSP. (author)

  9. Carbon leaching from tropical peat soils and consequences for carbon balances

    Directory of Open Access Journals (Sweden)

    Tim Rixen

    2016-07-01

    Full Text Available Drainage and deforestation turned Southeast (SE Asian peat soils into a globally important CO2 source, because both processes accelerate peat decomposition. Carbon losses through soil leaching have so far not been quantified and the underlying processes have hardly been studied. In this study, we use results derived from nine expeditions to six Sumatran rivers and a mixing model to determine leaching processes in tropical peat soils, which are heavily disturbed by drainage and deforestation. Here we show that a reduced evapotranspiration and the resulting increased freshwater discharge in addition to the supply of labile leaf litter produced by re-growing secondary forests increase leaching of carbon by ~200%. Enhanced freshwater fluxes and leaching of labile leaf litter from secondary vegetation appear to contribute 38% and 62% to the total increase, respectively. Decomposition of leached labile DOC can lead to hypoxic conditions in rivers draining disturbed peatlands. Leaching of the more refractory DOC from peat is an irrecoverable loss of soil that threatens the stability of peat-fringed coasts in SE Asia.

  10. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    Science.gov (United States)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  11. Forests and wood consumption on the carbon balance. Carbon emission reduction by use of wood products

    International Nuclear Information System (INIS)

    Sikkema, R.; Nabuurs, G.J.

    1995-01-01

    Until now studies on the greenhouse effect paid much attention to carbon fixation by forests, while the entire CO2 cycle of forests and forest products remained underexposed. Utilization of wood products instead of energy-intensive materials (plastics/steel) and fossil fuels (coal) proves to play an important role as well. The effect of utilization is even greater than that of fixation. In all, additional forests together with the multiple use of trees can contribute substantially to the reduction of CO2 emissions. The contribution can run from 5.3 ton CO2/ha/yr for a mixed forest of oak/beech to 18.9 ton CO2/ha/yr for energy plantations (poplar). 2 figs., 3 tabs

  12. Diurnal Variation in Gas Exchange: The Balance between Carbon Fixation and Water Loss.

    Science.gov (United States)

    Matthews, Jack S A; Vialet-Chabrand, Silvere R M; Lawson, Tracy

    2017-06-01

    Stomatal control of transpiration is critical for maintaining important processes, such as plant water status, leaf temperature, as well as permitting sufficient CO 2 diffusion into the leaf to maintain photosynthetic rates ( A ). Stomatal conductance often closely correlates with A and is thought to control the balance between water loss and carbon gain. It has been suggested that a mesophyll-driven signal coordinates A and stomatal conductance responses to maintain this relationship; however, the signal has yet to be fully elucidated. Despite this correlation under stable environmental conditions, the responses of both parameters vary spatially and temporally and are dependent on species, environment, and plant water status. Most current models neglect these aspects of gas exchange, although it is clear that they play a vital role in the balance of carbon fixation and water loss. Future efforts should consider the dynamic nature of whole-plant gas exchange and how it represents much more than the sum of its individual leaf-level components, and they should take into consideration the long-term effect on gas exchange over time. © 2017 American Society of Plant Biologists. All Rights Reserved.

  13. Global carbon - nitrogen - phosphorus cycle interactions: A key to solving the atmospheric CO2 balance problem?

    Science.gov (United States)

    Peterson, B. J.; Mellillo, J. M.

    1984-01-01

    If all biotic sinks of atmospheric CO2 reported were added a value of about 0.4 Gt C/yr would be found. For each category, a very high (non-conservative) estimate was used. This still does not provide a sufficient basis for achieving a balance between the sources and sinks of atmospheric CO2. The bulk of the discrepancy lies in a combination of errors in the major terms, the greatest being in a combination of errors in the major terms, the greatest being in the net biotic release and ocean uptake segments, but smaller errors or biases may exist in calculations of the rate of atmospheric CO2 increase and total fossil fuel use as well. The reason why biotic sinks are not capable of balancing the CO2 increase via nutrient-matching in the short-term is apparent from a comparison of the stoichiometry of the sources and sinks. The burning of fossil fuels and forest biomass releases much more CO2-carbon than is sequestered as organic carbon.

  14. Carbon balance of the typical grain crop rotation in Moscow region assessed by eddy covariance method

    Science.gov (United States)

    Meshalkina, Joulia; Yaroslavtsev, Alexis; Vassenev, Ivan

    2017-04-01

    Croplands could have equal or even greater net ecosystem production than several natural ecosystems (Hollinger et al., 2004), so agriculture plays a substantial role in mitigation strategies for the reduction of carbon dioxide emissions. In Central Russia, where agricultural soils carbon loses are 9 time higher than natural (forest's) soils ones (Stolbovoi, 2002), the reduction of carbon dioxide emissions in agroecosystems must be the central focus of the scientific efforts. Although the balance of the CO2 mostly attributed to management practices, limited information exists regarding the crop rotation overall as potential of C sequestration. In this study, we present data on carbon balance of the typical grain crop rotation in Moscow region followed for 4 years by measuring CO2 fluxes by paired eddy covariance stations (EC). The study was conducted at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Two fields of the four-course rotation were studied in 2013-2016. Crop rotation included winter wheat (Triticum sativum L.), barley (Hordeum vulgare L.), potato crop (Solanum tuberosum L.) and cereal-legume mixture (Vicia sativa L. and Avena sativa L.). Crops sowing occurred during the period from mid-April to mid-May depending on weather conditions. Winter wheat was sown in the very beginning of September and the next year it occurred from under the snow in the phase of tillering. White mustard (Sinapis alba) was sown for green manure after harvesting winter wheat in mid of July. Barley was harvested in mid of August, potato crop was harvested in September. Cereal-legume mixture on herbage was collected depending on the weather from early July to mid-August. Carbon uptake (NEE negative values) was registered only for the fields with winter wheat and white

  15. The Role of Stream Water Carbon Dynamics and Export in the Carbon Balance of a Tropical Seasonal Rainforest, Southwest China

    Science.gov (United States)

    Zhou, Wen-Jun; Zhang, Yi-Ping; Schaefer, Douglas A.; Sha, Li-Qing; Deng, Yun; Deng, Xiao-Bao; Dai, Kai-Jie

    2013-01-01

    A two-year study (2009 ∼ 2010) was carried out to investigate the dynamics of different carbon (C) forms, and the role of stream export in the C balance of a 23.4-ha headwater catchment in a tropical seasonal rainforest at Xishuangbanna (XSBN), southwest China. The seasonal volumetric weighted mean (VWM) concentrations of total inorganic C (TIC) and dissolved inorganic C (DIC) were higher, and particulate inorganic C (PIC) and organic C (POC) were lower, in the dry season than the rainy season, while the VWM concentrations of total organic C (TOC) and dissolved organic C (DOC) were similar between seasons. With increased monthly stream discharge and stream water temperature (SWT), only TIC and DIC concentrations decreased significantly. The most important C form in stream export was DIC, accounting for 51.8% of the total C (TC) export; DOC, POC, and PIC accounted for 21.8%, 14.9%, and 11.5% of the TC export, respectively. Dynamics of C flux were closely related to stream discharge, with the greatest export during the rainy season. C export in the headwater stream was 47.1 kg C ha−1 yr−1, about 2.85% of the annual net ecosystem exchange. This finding indicates that stream export represented a minor contribution to the C balance in this tropical seasonal rainforest. PMID:23437195

  16. The role of stream water carbon dynamics and export in the carbon balance of a tropical seasonal rainforest, southwest China.

    Directory of Open Access Journals (Sweden)

    Wen-Jun Zhou

    Full Text Available A two-year study (2009 ~ 2010 was carried out to investigate the dynamics of different carbon (C forms, and the role of stream export in the C balance of a 23.4-ha headwater catchment in a tropical seasonal rainforest at Xishuangbanna (XSBN, southwest China. The seasonal volumetric weighted mean (VWM concentrations of total inorganic C (TIC and dissolved inorganic C (DIC were higher, and particulate inorganic C (PIC and organic C (POC were lower, in the dry season than the rainy season, while the VWM concentrations of total organic C (TOC and dissolved organic C (DOC were similar between seasons. With increased monthly stream discharge and stream water temperature (SWT, only TIC and DIC concentrations decreased significantly. The most important C form in stream export was DIC, accounting for 51.8% of the total C (TC export; DOC, POC, and PIC accounted for 21.8%, 14.9%, and 11.5% of the TC export, respectively. Dynamics of C flux were closely related to stream discharge, with the greatest export during the rainy season. C export in the headwater stream was 47.1 kg C ha(-1 yr(-1, about 2.85% of the annual net ecosystem exchange. This finding indicates that stream export represented a minor contribution to the C balance in this tropical seasonal rainforest.

  17. Whole-system carbon balance for a regional temperate forest in Northern Wisconsin, USA

    Science.gov (United States)

    Peckham, S. D.; Gower, S. T.

    2010-12-01

    The whole-system (biological + industrial) carbon (C) balance was estimated for the Chequamegon-Nicolet National Forest (CNNF), a temperate forest covering 600,000 ha in Northern Wisconsin, USA. The biological system was modeled using a spatially-explicit version of the ecosystem process model Biome-BGC. The industrial system was modeled using life cycle inventory (LCI) models for wood and paper products. Biome-BGC was used to estimate net primary production, net ecosystem production (NEP), and timber harvest (H) over the entire CNNF. The industrial carbon budget (Ci) was estimated by applying LCI models of CO2 emissions resulting from timber harvest and production of specific wood and paper products in the CNNF region. In 2009, simulated NEP of the CNNF averaged 3.0 tC/ha and H averaged 0.1 tC/ha. Despite model uncertainty, the CNNF region is likely a carbon sink (NEP - Ci > 0), even when CO2 emissions from timber harvest and production of wood and paper products are included in the calculation of the entire forest system C budget.

  18. Carbon Management In the Post-Cap-and-Trade Carbon Economy-Part II

    Science.gov (United States)

    DeGroff, F. A.

    2014-12-01

    This is the second installment in our search for a comprehensive economic model to mitigate climate change due to anthropogenic activity. Last year we presented how the unique features of our economic model measure changes in carbon flux due to anthropogenic activity, referred to as carbon quality or CQ, and how the model is used to value such changes in the climate system. This year, our paper focuses on how carbon quality can be implemented to capture the effect of economic activity and international trade on the climate system, thus allowing us to calculate a Return on Climate System (RoCS) for all economic assets and activity. The result is that the RoCS for each public and private economic activity and entity can be calculated by summing up the RoCS for each individual economic asset and activity in which an entity is engaged. Such a macro-level scale is used to rank public and private entities including corporations, governments, and even entire nations, as well as human adaptation and carbon storage activities, providing status and trending insights to evaluate policies on both a micro- and macro-economic level. With international trade, RoCS measures the embodied effects on climate change that will be needed to assess border fees to insure carbon parity on all imports and exports. At the core of our vision is a comprehensive, 'open-source' construct of which our carbon quality metric is the first element. One goal is to recognize each country's endemic resources and infrastructure that affect their ability to manage carbon, while preventing spatial and temporal shifting of carbon emissions that reduce or reverse efforts to mitigate climate change. The standards for calculating the RoCS can be promulgated as part of the Generally Accepted Accounted Principles (GAAP) and the International Financial Reporting Standards (IFRS) to ensure standard and consistent reporting. The value of such insights on the climate system at all levels will be crucial to managing

  19. The impacts of tropical cyclones on the net carbon balance of eastern US forests (1851-2000)

    Science.gov (United States)

    Fisk, J. P.; Hurtt, G. C.; Chambers, J. Q.; Zeng, H.; Dolan, K. A.; Negrón-Juárez, R. I.

    2013-12-01

    In temperate forests of the eastern US, tropical cyclones are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial progress has been made to quantify forest damage and resulting gross carbon emissions from tropical cyclones. However, the net effect of storms on the carbon balance of forests depends not only on the biomass lost in single events, but also on the uptake during recovery from a mosaic of past events. This study estimates the net impacts of tropical cyclones on the carbon balance of US forests over the period 1851-2000. To track both disturbance and recovery and to isolate the effects of storms, a modeling framework is used combining gridded historical estimates of mortality and damage with a mechanistic model using an ensemble approach. The net effect of tropical cyclones on the carbon balance is shown to depend strongly on the spatial and temporal scales of analysis. On average, tropical cyclones contribute a net carbon source over latter half of the 19th century. However, throughout much of the 20th century a regional carbon sink is estimated resulting from periods of forest recovery exceeding damage. The large-scale net annual flux resulting from tropical cyclones varies by up to 50 Tg C yr-1, an amount equivalent to 17%-36% of the US forest carbon sink.

  20. The impacts of tropical cyclones on the net carbon balance of eastern US forests (1851–2000)

    International Nuclear Information System (INIS)

    Fisk, J P; Hurtt, G C; Dolan, K A; Chambers, J Q; Zeng, H; Negrón-Juárez, R I

    2013-01-01

    In temperate forests of the eastern US, tropical cyclones are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial progress has been made to quantify forest damage and resulting gross carbon emissions from tropical cyclones. However, the net effect of storms on the carbon balance of forests depends not only on the biomass lost in single events, but also on the uptake during recovery from a mosaic of past events. This study estimates the net impacts of tropical cyclones on the carbon balance of US forests over the period 1851–2000. To track both disturbance and recovery and to isolate the effects of storms, a modeling framework is used combining gridded historical estimates of mortality and damage with a mechanistic model using an ensemble approach. The net effect of tropical cyclones on the carbon balance is shown to depend strongly on the spatial and temporal scales of analysis. On average, tropical cyclones contribute a net carbon source over latter half of the 19th century. However, throughout much of the 20th century a regional carbon sink is estimated resulting from periods of forest recovery exceeding damage. The large-scale net annual flux resulting from tropical cyclones varies by up to 50 Tg C yr −1 , an amount equivalent to 17%–36% of the US forest carbon sink. (letter)

  1. Impacts of climate mitigation strategies in the energy sector on global land use and carbon balance

    Science.gov (United States)

    Engström, Kerstin; Lindeskog, Mats; Olin, Stefan; Hassler, John; Smith, Benjamin

    2017-09-01

    Reducing greenhouse gas emissions to limit damage to the global economy climate-change-induced and secure the livelihoods of future generations requires ambitious mitigation strategies. The introduction of a global carbon tax on fossil fuels is tested here as a mitigation strategy to reduce atmospheric CO2 concentrations and radiative forcing. Taxation of fossil fuels potentially leads to changed composition of energy sources, including a larger relative contribution from bioenergy. Further, the introduction of a mitigation strategy reduces climate-change-induced damage to the global economy, and thus can indirectly affect consumption patterns and investments in agricultural technologies and yield enhancement. Here we assess the implications of changes in bioenergy demand as well as the indirectly caused changes in consumption and crop yields for global and national cropland area and terrestrial biosphere carbon balance. We apply a novel integrated assessment modelling framework, combining three previously published models (a climate-economy model, a socio-economic land use model and an ecosystem model). We develop reference and mitigation scenarios based on the narratives and key elements of the shared socio-economic pathways (SSPs). Taking emissions from the land use sector into account, we find that the introduction of a global carbon tax on the fossil fuel sector is an effective mitigation strategy only for scenarios with low population development and strong sustainability criteria (SSP1 Taking the green road). For scenarios with high population growth, low technological development and bioenergy production the high demand for cropland causes the terrestrial biosphere to switch from being a carbon sink to a source by the end of the 21st century.

  2. Impacts of climate mitigation strategies in the energy sector on global land use and carbon balance

    Directory of Open Access Journals (Sweden)

    K. Engström

    2017-09-01

    Full Text Available Reducing greenhouse gas emissions to limit damage to the global economy climate-change-induced and secure the livelihoods of future generations requires ambitious mitigation strategies. The introduction of a global carbon tax on fossil fuels is tested here as a mitigation strategy to reduce atmospheric CO2 concentrations and radiative forcing. Taxation of fossil fuels potentially leads to changed composition of energy sources, including a larger relative contribution from bioenergy. Further, the introduction of a mitigation strategy reduces climate-change-induced damage to the global economy, and thus can indirectly affect consumption patterns and investments in agricultural technologies and yield enhancement. Here we assess the implications of changes in bioenergy demand as well as the indirectly caused changes in consumption and crop yields for global and national cropland area and terrestrial biosphere carbon balance. We apply a novel integrated assessment modelling framework, combining three previously published models (a climate–economy model, a socio-economic land use model and an ecosystem model. We develop reference and mitigation scenarios based on the narratives and key elements of the shared socio-economic pathways (SSPs. Taking emissions from the land use sector into account, we find that the introduction of a global carbon tax on the fossil fuel sector is an effective mitigation strategy only for scenarios with low population development and strong sustainability criteria (SSP1 Taking the green road. For scenarios with high population growth, low technological development and bioenergy production the high demand for cropland causes the terrestrial biosphere to switch from being a carbon sink to a source by the end of the 21st century.

  3. Carbon balance of rewetted and drained peat soils used for biomass production: A mesocosm study

    DEFF Research Database (Denmark)

    Karki, Sandhya; Elsgaard, Lars; Kandel, Tanka

    2016-01-01

    of lower CO2 emissions without losing agricultural land. The present study quantified the carbon balance (CO2, CH4 and harvested biomass C) of rewetted and drained peat soils under intensively managed reed canary grass (RCG) cultivation. Mesocosms were maintained at five different ground water levels (GWL......), i.e., 0, 10, 20 cm below the soil surface, representing rewetted peat soils, and 30 and 40 cm below the soil surface, representing drained peat soils. Net ecosystem exchange (NEE) of CO2 and CH4 emissions were measured during the growing period of RCG (May to September) using transparent and opaque...... closed chamber methods. The average dry biomass yield was significantly lower from rewetted peat soils (12 Mg ha−1) than drained peat soils (15 Mg ha−1). Also, CO2 fluxes of gross primary production (GPP) and ecosystem respiration (ER) from rewetted peat soils were significantly lower than drained peat...

  4. Comparison of a Mass Balance and an Ecosystem Model Approach when Evaluating the Carbon Cycling in a Lake Ecosystem

    International Nuclear Information System (INIS)

    Andersson, Eva; Sobek, Sebastian

    2006-01-01

    Carbon budgets are frequently used in order to understand the pathways of organic matter in ecosystems, and they also have an important function in the risk assessment of harmful substances. We compared two approaches, mass balance calculations and an ecosystem budget, to describe carbon processing in a shallow, oligotrophic hardwater lake. Both approaches come to the same main conclusion, namely that the lake is a net auto trophic ecosystem, in spite of its high dissolved organic carbon and low total phosphorus concentrations. However, there were several differences between the carbon budgets, e.g. in the rate of sedimentation and the air-water flux of CO 2 . The largest uncertainty in the mass balance is the contribution of emergent macrophytes to the carbon cycling of the lake, while the ecosystem budget is very sensitive towards the choice of conversion factors and literature values. While the mass balance calculations produced more robust results, the ecosystem budget gave valuable insights into the pathways of organic matter transfer in the ecosystem. We recommend that when using an ecosystem budget for the risk assessment of harmful substances, mass balance calculations should be performed in parallel in order to increase the robustness of the conclusions

  5. The carbon balance of South America: a review of the status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-12-01

    Full Text Available We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1 and close to neutral (~ 0.1 Pg C a−1 in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation.

    Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent

  6. Effect of Forest Management of Picea abies and Fagus sylvatica with Different Types of Felling on Carbon and Economic Balances in the Czech Republic

    Science.gov (United States)

    Plch, Radek; Pulkrab, Karel; Bukáček, Jan; Sloup, Roman; Cudlín, Pavel

    2016-10-01

    The selection of the most sustainable forest management under given site conditions needs suitable criteria and indicators. For this purpose, carbon and economic balance assessment, completed with environmental impact computation using the Life Cycle Assessment (LCA) were used. The aim of this study was to compare forestry operations and wood production of selected forest stands with different i) tree species composition (Norway spruce - Picea abies and European beech - Fagus sylvatica) and ii) type of felling (chainsaw and harvester). Carbon and economic balance methods consist in the comparison of quantified inputs (fossil fuels, electricity, used machinery, fertilizers, etc., converted into emission units of carbon in Mg of C- CO2-eq. or EUR) with quantified outputs (biomass production in Mg of carbon or EUR). In this contribution, similar forest stands (“forest site complexes”) in the 4th forest vegetation zone (in the Czech Republic approximately 400-700 m above sea-level) were selected. Forestry operations were divided into 5 main stages: i) seedling production, ii) stand establishment and pruning, iii) thinning and final cutting, iv) skidding, and v) secondary timber transport and modelled for one rotation period of timber production (ca. 100 years). The differences between Norway spruce and European beech forest stands in the carbon efficiency were relatively small while higher differences were achieved in the economic efficiency (forest stands with Norway spruce had a higher economic efficiency). Concerning the comparison of different types of felling in Norway spruce forest stands, the harvester use proved to induce significantly higher environmental impacts (emission of carbon) and lower economic costs. The comparison of forestry operation stages showed that the main part of carbon emissions, originating from fuel production and combustion, is connected with a thinning and final cutting, skidding and secondary timber transport in relations to

  7. Heat Balance Study on Integrated Cycles for Hydrogen and Electricity Generation in VHTR - Part 2 -

    International Nuclear Information System (INIS)

    Lee, Sang Il; Yoo, Yeon Jae; Heo, Gyunyoung; Park, Soyoung; Kang, Yeon Kwan

    2015-01-01

    In the paper, reverse engineering was performed on SCMHR proposed by NGNP to reconstruct it into PEPSE. This model was used to analyze sensitivity of key variables. The paper also presented a concept design of thermal cycle, where heat of nuclear reactor is partially used for hydrogen production and remaining heat is used to generate power through IHX. This study introduces the results of concept designs on thermal cycle constructed using methods that are somewhat different from the previous results. As for the first method, efficiency under main steam condition proposed by NGNP was analyzed using ultra supercritical steam cycle, which exhibits highest efficiency among commercial technologies available. Another method was to prepare heat balance using supercritical CO 2 cycle, which has recently been commercialized in small scale and is undergoing R and D efforts for scale-up. As a part of concept design for high temperature gas reactor, this paper attempts different types of electricity generation cycle design and compares their advantages and disadvantages. A reference model was developed to change original design of NGNP. Sensitivity analysis can be performed according to changing performance of facility and external conditions. A Rankine cycle model operated under SC or USC condition was created by adding to a previous study to carry out key sensitivity analysis. Data for future design will be prepared through supplementary study, and the ultimate objective is to make contribution to optimal design of high temperature gas reactor

  8. Heat Balance Study on Integrated Cycles for Hydrogen and Electricity Generation in VHTR - Part 2 -

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Il; Yoo, Yeon Jae [Hyundai Engineering Company Ltd., Seouul (Korea, Republic of); Heo, Gyunyoung; Park, Soyoung; Kang, Yeon Kwan [Kyung Hee University, Yongin (Korea, Republic of)

    2015-10-15

    In the paper, reverse engineering was performed on SCMHR proposed by NGNP to reconstruct it into PEPSE. This model was used to analyze sensitivity of key variables. The paper also presented a concept design of thermal cycle, where heat of nuclear reactor is partially used for hydrogen production and remaining heat is used to generate power through IHX. This study introduces the results of concept designs on thermal cycle constructed using methods that are somewhat different from the previous results. As for the first method, efficiency under main steam condition proposed by NGNP was analyzed using ultra supercritical steam cycle, which exhibits highest efficiency among commercial technologies available. Another method was to prepare heat balance using supercritical CO{sub 2} cycle, which has recently been commercialized in small scale and is undergoing R and D efforts for scale-up. As a part of concept design for high temperature gas reactor, this paper attempts different types of electricity generation cycle design and compares their advantages and disadvantages. A reference model was developed to change original design of NGNP. Sensitivity analysis can be performed according to changing performance of facility and external conditions. A Rankine cycle model operated under SC or USC condition was created by adding to a previous study to carry out key sensitivity analysis. Data for future design will be prepared through supplementary study, and the ultimate objective is to make contribution to optimal design of high temperature gas reactor.

  9. Balance of constructive and destructive carbonate processes on mesophotic coral reefs

    Science.gov (United States)

    Weinstein, D. K.; Klaus, J. S.; Smith, T. B.; Helmle, K. P.; Marshall, D.

    2013-12-01

    Net carbonate accumulation of coral reefs is the product of both constructive and destructive processes that can ultimately influence overall reef geomorphology. Differences in these processes with depth may in part explain why the coral growth-light intensity association does no result in the traditionally theorized reef accretion decrease with depth. Until recently, physical sampling limitations had prevented the acquisition of sedimentary data needed to assess in situ carbonate accumulation in mesophotic reefs (30-150 m). Coral framework production, secondary carbonate production (calcareous encrusters), and bioerosion, the three most critical components of net carbonate accumulation, were analyzed in mesophotic reefs more than 10 km south of St. Thomas, U.S. Virgin Islands along a very gradual slope that limits sediment transport and sedimentation. Recently dead samples of the massive coral, Orbicella annularis collected from three structurally different upper mesophotic coral reef habitats (30-45 m) were cut parallel to the primary growth axis to identify density banding through standard x-radiographic techniques. Assuming annual banding, mesophotic linear extension rates were calculated on the order of 0.7-1.5 mm/yr. Weight change of experimental coral substrates exposed for 3 years indicate differing rates (1.1-17.2 g/yr) of bioerosion and secondary accretion between mesophotic sites. When correcting bioerosion rates for high mesophotic skeletal density, carbonate accumulation rates were found to vary significantly between neighboring mesophotic reefs with distinctive structures. Results imply variable rates of mesophotic reef net carbonate accretion with the potential to influence overall reef/platform morphology, including localized mesophotic reef structure.

  10. Brazilian environmental legislation and scenarios for carbon balance in Areas of Permanent Preservation (APP) in dairy livestock regions

    Science.gov (United States)

    Hott, M. C.; Fonseca, L. D.; Andrade, R. G.

    2011-12-01

    The present study aimed at mapping some categories of Areas of Permanent Preservation (APP) for natural regeneration of semideciduous forests in the regions of Zona da Mata and Campo das Vertentes, Minas Gerais State (Figure 1), and from this to establish what impact the deployment of APP over area of pastures and subsequently milk production and carbon sequestration, considering areas of pasture as one of major factors for the dairy farming in the regions concerned. From the altimetric information from MDE, it was possible to extract morphological and morphometrical data to estimate the areas of APP. We used imagery of MODIS/Terra for extraction of the pastures areas from the vegetation index data NDVI to intersect with the estimated area of APP. In a linear or deterministic scenario of deployment of APPs over in the pasture areas considering that wich are proportionately responsible for sizing the herd, and thus for the milk production in extensive livestock, despite the existence of numerous other factors, there would be an impact 12% in the production of Campo das Vertentes region and 21.5% for the Zona da Mata. In this scenario, according to the carbon balance of forests and livestock, there would be a positive balance with the deployment of areas of permanent preservation and, subsequent promotion of natural regeneration. Considering the current grazing area of the Zona da Mata and Campo das Vertentes, 1.6 million hectares, with the carbon balance estimated at 1 ton/hectare/year, 300,000 hectares would have a balance of 5 ton/hectare/year in whole cycle of 40 years, totaling 200 tons carbon by hectare, or additional 48 million tons fixed, considering 4 tons more than pastures in the case of semideciduous forest. At the end of the cycle or forest climax, there would still be positive carbon balance, estimated as a balance of 2 ton/hectare/year. However, despite the higher carbon balance for the semideciduous forest, compared to livestock, it is important to

  11. Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

    Institute of Scientific and Technical Information of China (English)

    W. Kolby SMITH; Wei GAO; Heidi STELTZER

    2009-01-01

    One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth's surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

  12. Carbon Balance at Landscape Level inferred fromTower CO2 Concentration Measurements

    Science.gov (United States)

    Chen, J. M.; Chen, B.; Higuchi, K.; Chan, D.; Shashkov, A.; Lin, H.; Liu, J.

    2003-04-01

    Terrestrial carbon sinks are considerable in the global carbon budget, but the accumulation of carbon in terrestrial ecosystems is very small (~0.2% per year) relative to the total carbon stocks in forests. Currently, eddy-covariance instruments mounted on towers are the only reliable means to measure carbon balance of a land surface, albeit limited to small areas and not free of caveats. In our quest of understanding the collective performance of ecosystems under the changing climate, it is highly desirable to have the ability to acquire carbon cycle information for large areas (landscape) consisting of patches of different ecosystems. For this purpose we explored methodologies of inferring carbon cycle information from tower CO2 concentration measurements affected by large areas (100-10000 km2). An ecosystem model named Boreal Ecosystem Productivity Simulator (BEPS) is coupled with a carbon-specific Vertical Diffusion Scheme (VDS) in order to decipher temporal variations in CO2 for landscape-level photosynthesis and respiration information. The coupled BEPS-VDS is applied to a unique 9-year (1990-2000 with 1997-8 missing data) 5-minute CO2 record measured on a 40-m tower over boreal forests near Fraserdale, Ontario, Canada. Over the period, the mean diurnal amplitude of the measured CO2 at 40 m increased by 5.58 ppmv, or 28% in the growing season. The increase in nighttime ecosystem respiration, causing the increase in the daily maximum CO2 concentration, was responsible for 65% of the increase in the diurnal amplitude, i.e., 3.61 ppmv, corresponding to an increase in the mean daily air temperature by about 2.77 degC and precipitation by 5% over the same period. The rest (35%) is explained by the increase in ecosystem daytime photosynthesis, causing the decrease in the daily minimum CO2 concentration. As the nighttime stable boundary layer (SBL) (270-560 m) was much shallower than the daytime convective boundary layer (CBL) (1000-1600 m), the increase in

  13. The Crc protein inhibits the production of polyhydroxyalkanoates in Pseudomonas putida under balanced carbon/nitrogen growth conditions.

    Science.gov (United States)

    La Rosa, Ruggero; de la Peña, Fernando; Prieto, María Axiliadora; Rojo, Fernando

    2014-01-01

    Pseudomonas putida synthesizes polyhydroxyalkanoates (PHAs) as storage compounds. PHA synthesis is more active when the carbon source is in excess and the nitrogen source is limiting, but can also occur at a lower rate under balanced carbon/nitrogen ratios. This work shows that PHA synthesis is controlled by the Crc global regulator, a protein that optimizes carbon metabolism by inhibiting the expression of genes involved in the use of non-preferred carbon sources. Crc acts post-transcriptionally. The mRNAs of target genes contain characteristic catabolite activity (CA) motifs near the ribosome binding site. Sequences resembling CA motifs can be predicted for the phaC1 gene, which codes for a PHA polymerase, and for phaI and phaF, which encode proteins associated to PHA granules. Our results show that Crc inhibits the translation of phaC1 mRNA, but not that of phaI or phaF, reducing the amount of PHA accumulated in the cell. Crc inhibited PHA synthesis during exponential growth in media containing a balanced carbon/nitrogen ratio. No inhibition was seen when the carbon/nitrogen ratio was imbalanced. This extends the role of Crc beyond that of controlling the hierarchical utilization of carbon sources and provides a link between PHA synthesis and the global regulatory networks controlling carbon flow. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Multi-year net ecosystem carbon balance at a horticulture-extracted restored peatland

    Science.gov (United States)

    Nugent, Kelly; Strachan, Ian; Strack, Maria

    2017-04-01

    small source of CO2, NEE in the Typha plots showed significantly greater CO2 uptake capacity relative to any other restored plant community. High productivity combined with reduced CH4 flux suggests that Typha may be playing a key role in reducing the overall impact of the remnant ditches on the net ecosystem carbon balance. A preliminary footprint analysis suggests that ecosystem-level CH4 flux is being primarily driven by release from hotspots while the majority of the tower source area is a very small source of methane.

  15. Gas chromatographic quantitative analysis of the gaseous emissions and carbon balance in the alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    C. Chon

    1997-06-01

    ln order to try to answer to this question, methods able to analyse simultaneously and quantitatively the liquid phase, the gaseous emissions and the biomass are needed. Recently, we have shown that under suitable defined conditions 13C NMR spectroscopy allows the quantitative measurement of at least eight components present at a concentration up to 5 x 10-3M (glycerol, glucose, butandiols, tartric, malic, lactic, citric and succinic acids in a short time (one hour with a precision of about 3 p. cent. The measurements of the ethanol concentrations and of the amount of carbon transferred in the biomass are easily achieved using respectively ebullioscopic and standard combustion techniques. We are now able to extend these results and to show that, by using gas chromatography in a continuous dynamic mode and under a sweep of air at the head space of the fermentor, it is possible to measure quantitatively the mixture of volatile substances (composed mainly of air, carbon dioxide, ethanol and water emanating from an alcoholic fermentation. The results obtained, when correlated with quantitative 13C NMR spectroscopy on the medium components permits the total balance sheet of the carbon transfers occuring during the fermentation process betwcen the liquid and the gaseous phases to be established. Our results indicate that the losses of ethanol during the fermentation process conducted under an air flow at the head space of the fermentor, may reach about 10 p. cent of the theoretical maximal amount of ethanol produced. The experiments presented here could explain the ethanol losses observed during some vinification processes conducted in open tanks.

  16. In search of work/life balance: trainee perspectives on part-time obstetrics and gynaecology specialist training

    OpenAIRE

    Henry Amanda; Clements Sarah; Kingston Ashley; Abbott Jason

    2012-01-01

    Abstract Background Part-time training (PTT) is accessed by approximately 10% of Australian obstetrics and gynaecology trainees, a small but increasing minority which reflects the growing demand for improved work/life balance amongst the Australian medical workforce. This survey reports the attitudes and experiences of both full-time and part-time trainees to PTT. Methods An email-based anonymous survey was sent to all Australian obstetrics and gynaecology trainees in April 2009, collecting d...

  17. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced

  18. Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

    Directory of Open Access Journals (Sweden)

    K. Yamanoi

    2015-12-01

    Full Text Available Forests play an important role in the terrestrial carbon balance, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The CO2 flux has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia in Hokkaido, where incidental damage by the strong Typhoon Songda in 2004 occurred. We also used the biometrical method to demonstrate the CO2 flux within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP, ecosystem respiration (Re, and net ecosystem production were 1350, 975, and 375 g C m−2 yr−1 before the disturbance and 1262, 1359, and −97 g C m−2 yr−1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed into a net carbon source. Because of increased light intensity at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead trees remaining at the study site, strongly affected the carbon balance over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds

  19. Carbon dioxide stripping in aquaculture. part 1: terminology and reporting

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ⇔ H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (<2000 μeq/kg), the difference between the true and apparent removal is small and can be ignored for many applications. Analytical and reporting standards are recommended to improve our understanding of carbon dioxide removal.

  20. Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

    International Nuclear Information System (INIS)

    Kolb, Thomas; Dore, Sabina; Montes-Helu, Mario

    2013-01-01

    We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006–10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability. (letter)

  1. Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

    Science.gov (United States)

    Kolb, Thomas; Dore, Sabina; Montes-Helu, Mario

    2013-03-01

    We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006-10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability.

  2. Differential responses of production and respiration to temperature and moisture drive the carbon balance across a climatic gradient in New Mexico

    Science.gov (United States)

    Kristina J. Anderson-Teixeira; John P. Delong; Andrew M. Fox; Daniel A. Brese; Marcy E. Litvak

    2011-01-01

    Southwestern North America faces an imminent transition to a warmer, more arid climate, and it is critical to understand how these changes will affect the carbon balance of southwest ecosystems. In order to test our hypothesis that differential responses of production and respiration to temperature and moisture shape the carbon balance across a range of spatio-temporal...

  3. Greenhouse gas balance of mountain dairy farms as affected by grassland carbon sequestration.

    Science.gov (United States)

    Salvador, Sara; Corazzin, Mirco; Romanzin, Alberto; Bovolenta, Stefano

    2017-07-01

    Recent studies on milk production have often focused on environmental impacts analysed using the Life Cycle Assessment (LCA) approach. In grassland-based livestock systems, soil carbon sequestration might be a potential sink to mitigate greenhouse gas (GHG) balance. Nevertheless, there is no commonly shared methodology. In this work, the GHG emissions of small-scale mountain dairy farms were assessed using the LCA approach. Two functional units, kg of Fat and Protein Corrected Milk (FPCM) and Utilizable Agricultural Land (UAL), and two different emissions allocations methods, no allocation and physical allocation, which accounts for the co-product beef, were considered. Two groups of small-scale dairy farms were identified based on the Livestock Units (LU) reared: 30 LU (HLU). Before considering soil carbon sequestration in LCA, performing no allocation methods, LLU farms tended to have higher GHG emission than HLU farms per kg of FPCM (1.94 vs. 1.59 kg CO 2 -eq/kg FPCM, P ≤ 0.10), whereas the situation was reversed upon considering the m 2 of UAL as a functional unit (0.29 vs. 0.89 kg CO 2 -eq/m 2 , P ≤ 0.05). Conversely, considering physical allocation, the difference between the two groups became less noticeable. When the contribution from soil carbon sequestration was included in the LCA and no allocation method was performed, LLU farms registered higher values of GHG emission per kg of FPCM than HLU farms (1.38 vs. 1.10 kg CO 2 -eq/kg FPCM, P ≤ 0.05), and the situation was likewise reversed in this case upon considering the m 2 of UAL as a functional unit (0.22 vs. 0.73 kg CO 2 -eq/m 2 , P ≤ 0.05). To highlight how the presence of grasslands is crucial for the carbon footprint of small-scale farms, this study also applied a simulation for increasing the forage self-sufficiency of farms to 100%. In this case, an average reduction of GHG emission per kg of FPCM of farms was estimated both with no allocation and with physical allocation

  4. Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; van der Linden, Leon; Lasslop, G.

    2012-01-01

    scale, direct climatic variability and changes in ecosystem functional properties regulated the IAV of the carbon balance at this site. Correlation analysis showed that the sensitivity of carbon fluxes to climatic variability was significantly higher at shorter than at longer time scales and changed...... seasonally. Ecosystem response anomalies implied that changes in the distribution of climate anomalies during the vegetation period will have stronger impacts on future ecosystem carbon balances than changes in average climate. We improved a published modelling approach which distinguishes the direct....... At the annual time scale as much as 80% of the IAV in NEE was attributed to the variation in photosynthesis and respiration related model parameters. Our results suggest that the observed decadal NEE trend at the investigated site was dominated by changes in ecosystem functioning. In general this study showed...

  5. Effect of forest drainage on the carbon balance and greenhouse impact of Finnish peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J.; Minkkinen, K.; Laiho, R. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The aim of this project is to produce an estimate of the change in the biomass and peat carbon stores arising from the drainage of peatlands for forestry, and of the change of greenhouse impact of these ecosystems. The study shows that the subsidence of mire surfaces due to drainage has been relatively small, on average about 20 cm. The observed increase in bulk density after drainage is caused by the physical compression of peat and the post-drainage input of organic material in the form of litter production from the above and below ground parts of the tree layer. Oxidative decay of organic matter may have further increased the compaction of peat, especially in fertile sites. When the changes in peat and vegetation carbon stores are summed up, it seems that, within the site types studied, the total impact of drainage to the ecosystem carbon store is close to zero on the nutrient rich sites and clearly positive on the poorer types. Water level drawdown in peatlands after drainage for forestry appears to decrease the greenhouse impact at least for a few hundred years. The estimated changes in all three emission components (CH{sub 4} emissions, CO{sub 2} sink from peatland and CO{sub 2} sequestered in trees) reduce the radiative forcing by approximately similar amounts

  6. Effect of forest drainage on the carbon balance and greenhouse impact of Finnish peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J; Minkkinen, K; Laiho, R [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1997-12-31

    The aim of this project is to produce an estimate of the change in the biomass and peat carbon stores arising from the drainage of peatlands for forestry, and of the change of greenhouse impact of these ecosystems. The study shows that the subsidence of mire surfaces due to drainage has been relatively small, on average about 20 cm. The observed increase in bulk density after drainage is caused by the physical compression of peat and the post-drainage input of organic material in the form of litter production from the above and below ground parts of the tree layer. Oxidative decay of organic matter may have further increased the compaction of peat, especially in fertile sites. When the changes in peat and vegetation carbon stores are summed up, it seems that, within the site types studied, the total impact of drainage to the ecosystem carbon store is close to zero on the nutrient rich sites and clearly positive on the poorer types. Water level drawdown in peatlands after drainage for forestry appears to decrease the greenhouse impact at least for a few hundred years. The estimated changes in all three emission components (CH{sub 4} emissions, CO{sub 2} sink from peatland and CO{sub 2} sequestered in trees) reduce the radiative forcing by approximately similar amounts

  7. Carbon Balance in an Irrigated Corn Field after Inorganic Fertilizer or Manure Application

    Science.gov (United States)

    Lentz, R. D.; Lehrsch, G. A.

    2014-12-01

    Little is known about inorganic fertilizer or manure effects on organic carbon (OC) and inorganic C (IC) losses from a furrow irrigated field, particularly in the context of other system C gains or losses. In 2003 and 2004, we measured dissolved organic and inorganic C (DOC, DIC), particulate OC and IC (POC, PIC) concentrations in irrigation inflow, runoff, and percolation waters (6-7 irrigations/y); C inputs from soil amendments and crop biomass; harvested C; and gaseous C emissions from field plots cropped to silage corn (Zea mays L.) in southern Idaho. Annual treatments included: (M) 13 (y 1) and 34 Mg/ha (y 2) stockpiled dairy manure; (F) 78 (yr 1) and 195 kg N/ha (y 2) inorganic N fertilizer; or (NA) no amendment--control. The mean annual total C input into M plots averaged 16.1 Mg/ha, 1.4-times greater than that for NA (11.5 Mg/ha) or F (11.1 Mg/ha), while total C outputs for the three treatments were similar, averaging 11.8 Mg/ha. Thus, the manure plots ended each growing season with an average net gain of 3.8 Mg C/ha (a positive net C flux), while the control (-0.5 Mg C/ha) and fertilizer (-0.4 Mg C/ha) treatments finished the season with a net C loss. Atmospheric CO2 incorporated into the crop biomass contributed 96% of the mean annual C input to NA and F plots but only 68% to M plots. We conclude that nutrient amendments substantially influence the short-term carbon balance of our furrow-irrigated system. Amendments had both direct and indirect influences on individual C components, such as the losses of DIC and POC in runoff and DOC in percolation water, producing temporally complex outcomes which may depend on environmental conditions external to the field.

  8. Carbon balance of a boreal bog during a year with an exceptionally dry summer

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.; Silvola, J. [Univ. of Joensuu (Finland). Dept. of Biology; Schulman, L. [Univ. of Helsinki (Finland). Dept. of Ecology and Systematics; Walden, J. [Finnish Meteorological Inst., Helsinki (Finland); Nykaenen, H.; Martikainen, P.J. [National Public Health Inst., Kuopio (Finland). Lab. of Environmental Microbiology

    1999-01-01

    Northern peatlands are important terrestrial carbon stores, and they show large spatial and temporal variation in the atmospheric exchange of CO{sub 2} and CH{sub 4}. Thus, annual carbon balance must be studied in detail in order to predict the climatic responses of these ecosystems. Closed-chamber methods were used to study CO{sub 2} and CH{sub 4} in hollow, Sphagnum angustifolium lawn. S. fuscum lawn, and hummock microsites within an ombrotrophic S. fuscum bog. Micrometeorological tower measurements were used as a reference for the CH{sub 3} efflux from the bog. Low precipitation during May--August in 1994 and a warm July--August period caused the water table to drop by more than 15 cm below the peat surface in the hollows and to 48 cm below the surface in high hummocks. Increased annual total respiration exceeded gross production and resulted in a net C loss of 4--157 g/m{sup 2} in the different microsites. Drought probably caused irreversible desiccation in some lawns of S. angustifolium and S. balticum and in S. fuscum in the hummocks, while S. balticum growing in hollows retained its moisture and even increased its photosynthetic capacity during the July--August period. Seasonal (12 May--4 October) CH{sub 4} emissions ranged from 2 g CH{sub 4}-C/m{sup 2} in drier S. fuscum hummocks and lawns to 7 and 14 g/m{sup 2} in wetter S. angustifolium-S. balticum lawns and hollows, respectively.

  9. Characterizing biospheric carbon balance using CO2 observations from the OCO-2 satellite

    Directory of Open Access Journals (Sweden)

    S. M. Miller

    2018-05-01

    Full Text Available NASA's Orbiting Carbon Observatory 2 (OCO-2 satellite launched in summer of 2014. Its observations could allow scientists to constrain CO2 fluxes across regions or continents that were previously difficult to monitor. This study explores an initial step toward that goal; we evaluate the extent to which current OCO-2 observations can detect patterns in biospheric CO2 fluxes and constrain monthly CO2 budgets. Our goal is to guide top-down, inverse modeling studies and identify areas for future improvement. We find that uncertainties and biases in the individual OCO-2 observations are comparable to the atmospheric signal from biospheric fluxes, particularly during Northern Hemisphere winter when biospheric fluxes are small. A series of top-down experiments indicate how these errors affect our ability to constrain monthly biospheric CO2 budgets. We are able to constrain budgets for between two and four global regions using OCO-2 observations, depending on the month, and we can constrain CO2 budgets at the regional level (i.e., smaller than seven global biomes in only a handful of cases (16 % of all regions and months. The potential of the OCO-2 observations, however, is greater than these results might imply. A set of synthetic data experiments suggests that retrieval errors have a salient effect. Advances in retrieval algorithms and to a lesser extent atmospheric transport modeling will improve the results. In the interim, top-down studies that use current satellite observations are best-equipped to constrain the biospheric carbon balance across only continental or hemispheric regions.

  10. Applying hot wire anemometry to directly measure the water balance in a proton exchange membrane fuel cell - Part 1

    DEFF Research Database (Denmark)

    Berning, Torsten; Al Shakhshir, Saher

    2015-01-01

    In order to accurately determine the water balance of a proton exchange membrane fuel cell it has recently been suggested to employ constant temperature anemometry (CTA), a frequently used method to measure the velocity of a fluid stream. CTA relies on convective heat transfer around a heated wire...... the equations required to calculate the heat transfer coefficient and the resulting voltage signal as function of the fuel cell water balance. The most critical and least understood part is the determination of the Nusselt number to calculate the heat transfer between the wire and the gas stream. Different...... expressions taken from the literature will be examined in detail, and it will be demonstrated that the power-law approach suggested by Hilpert is the only useful one for the current purposes because in this case the voltage response from the hot-wire sensor E/E0 shows the same dependency to the water balance...

  11. Crop Management Effects on the Energy and Carbon Balances of Maize Stover-Based Ethanol Production

    Directory of Open Access Journals (Sweden)

    Prem Woli

    2014-12-01

    Full Text Available This study was conducted to identify the crop management options—the combinations of various cultivars, irrigation amounts, planting dates, and soils—that would maximize the energy sustainability and eco-friendliness of maize (Zea mays L. stover-based ethanol production systems in the Mississippi Delta. Stover yields simulated with CERES-Maize were used to compute net energy value (NEV and carbon credit balance (CCB, the indicators of sustainability and eco-friendliness of ethanol production, respectively, for various scenarios. As the results showed, deeper soils with higher water holding capacities had larger NEV and CCB values. Both NEV and CCB had sigmoid relationships with irrigation amount and planting date and could be maximized by planting the crop during the optimum planting window. Stover yield had positive effects on NEV and CCB, whereas travel distance had negative. The influence of stover yield was larger than that of travel distance, indicating that increasing feedstock yields should be emphasized over reducing travel distance. The NEV and CCB values indicated that stover-based ethanol production in the Mississippi Delta is sustainable and environmentally friendly. The study demonstrated that the energy sustainability and eco-friendliness of maize stover-based ethanol production could be increased with alternative crop management options.

  12. Modelling of the carbon and water balances of olive (Olea europaea, L.)

    International Nuclear Information System (INIS)

    Villalobos, F.J.

    1999-01-01

    Olive orchards are the main component of numerous agricultural systems in the Mediterranean region. In this work we present the development of a simulation model of olive orchards, which is used here to illustrate some specific features of the water and carbon balances of olives. The fraction of daily Photosynthetically-Active Radiation (PAR) intercepted by the trees (Qd) changes substantially with solar declination. For a given LAI Qd increases as tree size is smaller. Canopy volume has a much larger effect on Qd than Leaf Area Density (LAD), implying that a submodel for canopy volume will be required. Estimates of Radiation-Use Efficiency for yield are 0.35 g dry matter/(MJ PAR) and 0.16 g oil/(MJ PAR) which are around 80% of those for sunflower under the same environment. Crop evaporation in olive orchards is characterized by a high proportion of evaporation from the soil surface (Es) and by the response of stomata to air humidity. Results from a evapotranspiration corresponds to Es, and that Water-Use Efficiency relative to transpiration is 0.9 kg fruit dry matter m-3, which is equal to that of sunflower. Important gaps in our knowledge of olive ecophysiology (dry matter partitioning and growth) require further research

  13. Mass, energy and material balances of SRF production process. Part 3: solid recovered fuel produced from municipal solid waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2015-02-01

    This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% of the input waste material was recovered in the form of solid recovered fuel; 2.6% as ferrous metal, 0.4% as non-ferrous metal, 11% was sorted as rejects material, 12% as fine faction and 2% as heavy fraction. The energy balance of the solid recovered fuel production process showed that 86% of the total input energy content of input waste material was recovered in the form of solid recovered fuel. The remaining percentage (14%) of the input energy was split into the streams of reject material, fine fraction and heavy fraction. The material balances of this process showed that mass fraction of paper and cardboard, plastic (soft) and wood recovered in the solid recovered fuel stream was 88%, 85% and 90%, respectively, of their input mass. A high mass fraction of rubber material, plastic (PVC-plastic) and inert (stone/rock and glass particles) was found in the reject material stream. © The Author(s) 2014.

  14. Carbon balance of a southern taiga spruce stand in European Russia

    International Nuclear Information System (INIS)

    Milyukova, I.M.; Varlagin, A.V.; Vygodskaya, N.N.; Kolle, O.; Schulze, E.D.; Lloyd, J.

    2002-01-01

    We present results from nearly three years of net ecosystem flux measurements above a boreal spruce stand growing in European Russia. Fluxes were measured by eddy covariance using conventional techniques. In all years examined (1998-2000), the forest was a significant source of carbon to the atmosphere. However, the magnitude of this inferred source depended upon assumptions regarding the degree of 'flux loss' under conditions of low turbulence, such as typically occur at night. When corrections were not made, the forest was calculated to be only a modest source of C to the atmosphere (3-5 mol C/m 2 /yr). However, when the corrections were included, the apparent source was much larger (20-30 mol C/m 2 /yr). Using a simple model to describe the temperature dependencies of ecosystem respiration on air and soil temperatures, about 80% of the night-time flux was inferred to be from soil respiration, with the remainder being attributable to foliage, branches and boles. We used reasonable assumptions to estimate the rate of ecosystem respiration during the day, allowing an estimation of canopy photosynthetic rates and hence the annual Gross Primary Productivity of the ecosystem. For the two full years examined (1999 and 2000), this was estimated at 122 and 130 mol C/m 2 /yr, respectively. This value is similar to estimates for boreal forests in Scandinavia, but substantially higher than has been reported for Canadian or Siberian boreal forests. There was a clear tendency for canopy photosynthetic rates to increase with both light and temperature, but the slope of the temperature response of photosynthesis was less steep that that of ecosystem respiration. Thus, on most warm days in summer the forest was a substantial source of carbon to the atmosphere; with the forest usually being a net sink only on high insolation days where the average daily air temperatures were below about 18 deg C. These data, along with other studies on the current balance of boreal ecosystems

  15. [Carbon balance of household production system in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau, China].

    Science.gov (United States)

    Wu, Chao Chao; Gao, Xiao Ye; Hou, Fu Jiang

    2017-10-01

    The transition zone from the Loess Plateau to the Qinghai-Tibet Plateau is one of the regions with most dramatic changes in agricultural production mode and most sensitive response to the carbon balance effect. This paper analyzed the carbon balance of the agriculture system along the altitude gradient in Tongwei, Weiyuan and Xiahe counties. The results showed that with the increase of altitude, the carbon emission, carbon fixation and carbon sink capacity of crops per unit area decreased accordingly, while the average carbon emission, carbon fixation and carbon source capacity of each household in livestock system increased. The integrated crop-livestock production system changed from carbon sink to carbon source. The average carbon emission of each household rose with altitude, but the carbon fixation was the opposite. The change of percentage ofhousehold in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau with carbon balance could be fitted with Logistic equation. In the crop system of Tongwei, Weiyuan and Xiahe with the altitude increase, carbon emission at the inflection point where the household percentage accounted for 50.0% was 1491, 857 and 376 kg CE·household -1 , and carbon fixation was 6187, 3872 and 778 kg CE·household -1 , respectively. For the livestock system, carbon emission was 2218, 3725 and 49511 kg CE·household -1 , and carbon fixation was 138, 230 and 2706 kg CE·household -1 , respectively. For the integrated crop-livestock system, carbon emission was 3615, 4583 and 49918 kg CE·household -1 , and carbon fixation was 6289, 4113 and 3819 kg CE·household -1 , respectively, which could be the key point for the regulation of regional carbon balance.

  16. Toward a consistency cross-check of eddy covariance flux–based and biometric estimates of ecosystem carbon balance

    DEFF Research Database (Denmark)

    Luyssaert, S.; Reichstein, M.; Schulze, E.-D.

    2009-01-01

    Quantification of an ecosystem's carbon balance and its components is pivotal for understanding both ecosystem functioning and global cycling. Several methods are being applied in parallel to estimate the different components of the CO2 balance. However, different methods are subject to different...... sources of error. Therefore, it is necessary that site level component estimates are cross-checked against each other before being reported. Here we present a two-step approach for testing the accuracy and consistency of eddy covariance–based gross primary production (GPP) and ecosystem respiration (Re...

  17. Forest Carbon Sequestration Subsidy and Carbon Tax as Part of China’s Forestry Policies

    Directory of Open Access Journals (Sweden)

    Jinhua Liu

    2017-02-01

    Full Text Available Forestry is an effective strategy for climate change mitigation. However, forestry activities not only sequester carbon but also release CO2. It is therefore important to formulate carbon subsidy and carbon taxation policies on the basis of the price of carbon. In this study, a forestry-based Computable General Equilibrium (CGE model was built by using input-output data of China in 2014 to construct a Social Accounting Matrix (SAM. The model simulates different carbon price scenarios and was used to explore the effects of carbon subsidy and carbon taxation policies on the forestry economy. The main results can be summarized as follows: When the carbon price is low, the implementation of the policy increases forestry output and causes forest product prices to rise. When the carbon price is high, the carbon tax will produce an inhibitory effect, and output and prices will decline. With the constant rise of the carbon price, value addition will decrease, with flow to other industries. For the carbon sequestration policy, there is a reasonable carbon price range bound. In light of these results, relevant policies are proposed.

  18. A versatile computer package for mechanism analysis, part 2: Dynamics and balance

    Science.gov (United States)

    Davies, T.

    The algorithms required for the shaking force components, the shaking moment about the crankshaft axis, and the input torque and bearing load components are discussed using the textile machine as a focus for the discussion. The example is also used to provide illustrations of the output for options on the hodograph of the shaking force vector. This provides estimates of the optimum contrarotating masses and their locations for a generalized primary Lanchester balancer. The suitability of generalized Lanchester balancers particularly for textile machinery, and the overall strategy used during the development of the package are outlined.

  19. Gross changes in forest area shape the future carbon balance of tropical forests

    Directory of Open Access Journals (Sweden)

    W. Li

    2018-01-01

    Full Text Available Bookkeeping models are used to estimate land-use and land-cover change (LULCC carbon fluxes (ELULCC. The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016 with the curves used previously in bookkeeping models from Houghton (1999 and Hansis et al. (2015. We find that the two latter models overestimate the long-term (100 years vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross, above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

  20. Gross changes in forest area shape the future carbon balance of tropical forests

    Science.gov (United States)

    Li, Wei; Ciais, Philippe; Yue, Chao; Gasser, Thomas; Peng, Shushi; Bastos, Ana

    2018-01-01

    Bookkeeping models are used to estimate land-use and land-cover change (LULCC) carbon fluxes (ELULCC). The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data) and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016) with the curves used previously in bookkeeping models from Houghton (1999) and Hansis et al. (2015). We find that the two latter models overestimate the long-term (100 years) vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross), above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

  1. Inertia effects in rheometrical flow systems Part 2: The balance rheometer

    NARCIS (Netherlands)

    Waterman, H.A.

    1976-01-01

    The flow field of a linear viscoelastic fluid in the balance rheometer, taking fluid inertia into account, has been studied theoretically and an exact solution is given. The flow field of a Newtonian fluid is included in this solution as a special case. The forces and couples on the hemispheres are

  2. Potassium deficiency affects the carbon-nitrogen balance in cotton leaves.

    Science.gov (United States)

    Hu, Wei; Coomer, Taylor D; Loka, Dimitra A; Oosterhuis, Derrick M; Zhou, Zhiguo

    2017-06-01

    Potassium (K) plays important roles in the metabolism of carbon (C) and nitrogen (N), but studies of K deficiency affecting C-N balance are lacking. This study explored the influence of K deficiency on C-N interaction in cotton leaves by conducting a field experiment with cotton cultivar DP0912 under two K rates (K0: 0 kg K 2 O ha -1 and K67: 67 kg K 2 O ha -1 ) and a controlled environment experiment with K-deficient solution (K1: 0 mM K + ) and K-sufficient solution (K2: 6 mM K + ). The results showed that leaf K content, leaf number, leaf area, boll number, reproductive dry weight and total dry weight were significant lower under K deficiency (K0 or K1). Lower total chlorophyll content and Chl a/b ratio, and decreased Pn along with lower Gs and higher Ci were measured under K deficiency, suggesting that the decrease in Pn was resulted from non-stomatal limitation. Leaf glucose, fructose, sucrose and starch contents were higher under K deficiency, because lower sucrose export was detected in phloem. Although leaf nitrate and ammonium contents significantly decreased, free amino acid content was increased by 40-63% under K deficiency, since lower amino acid export was also measured in phloem. K deficiency also induced lower soluble protein content in leaves. Leaf ATP level was significantly increased under K deficiency, indicating ATP utilization was lower, so that less energy was supplied to C and N metabolism. The ratio of soluble sugar to free amino acid and the C/N ratio markedly increased under K deficiency, and one reason was that the phloem export reduced more prominent for sucrose (54.6-78.0%) than amino acid (36.7-85.4%) under K deficiency. In addition, lower phosphoenolpyruvate carboxylase activity limited malate and citrate biosynthesis under K deficiency, causing a decrease of C flux into the amino acids, which was not beneficial for maintaining C-N balance. Sucrose phosphate synthase and nitrate reductase activities were lower under K deficiency

  3. Interactions between biomass energy technologies and nutrient and carbon balances at the farm level

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, Uffe; Molt Petersen, B. [Danish Inst. of Agricultural Science, Dept. of Agroecology, Tjele (Denmark)

    2006-08-15

    Biomass energy is by far the largest renewable energy source in the world (IEA Renewable information (www.iea.org)). Biomass utilisation is closely linked to management and sustainability issues of forestry and agriculture. Carbon is extracted from forests and agriculture to bioenergy facilities, from where it is partly or fully emitted as CO{sub 2} and thus no longer available for sustaining soil organic matter content. Nutrients are extracted as well and, depending of the conversion technology, they may be recycled to farmland or lost as gaseous emissions. Thus, we must be able to describe these effects, and to suggest strategies to alleviate adverse effects on farm sustainability and on the environment. By choosing intelligent combinations of cropping systems and energy conversion technologies, win-win solutions may be achieved. This paper illustrates, via three cases, some agricultural impacts of choice of biomass technology and describes an intriguing possibility for recycling municipal or industrial wastes through the bioenergy chain. (au)

  4. The Impact of a Mild Sub-Critical Hydrothermal Carbonization Pretreatment on Umbila Wood. A Mass and Energy Balance Perspective

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cuvilas

    2015-03-01

    Full Text Available Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  5. Proportion of biogenic carbon in flue gas by carbon-14 measurement - part 2; Biohiili 2

    Energy Technology Data Exchange (ETDEWEB)

    Lehtomaeki, J.; Antson, O.; Hongisto, M. (VTT Technical Research Centre of Finland, Espoo (Finland)) (and others)

    2009-07-01

    The subject of this project is closely related to EU's emissions trading system and to the current and future monitoring needs therein. The determination of fossil part of emissions originated from various fuels by stack measurements or by laboratory analyses could possibly find users also in other fields outside the ETS - Emission Trading Scheme (e.g. waste incineration). After the market analysis and preliminary measurements carried out in the previous Biocarbon project this project focused on the development of the sampling method for stack measurements and to the validation of isotope measurements. The results obtained for fossil proportion of the fuel by current methods will be compared to those obtained by isotope measurements. The operation of the sampling system was tested in long period tests in plant conditions. Moreover, the sample preparation methods and isotope measurements were validated by measuring the proportions of biogenic and fossil carbon of known traffic fuel mixtures. The developed method can also be utilised as a fraud prevention measure related to the expanding international biofuels-trade. (orig.)

  6. Carbon stocks and greenhouse gas balance of an old-growth forest and an anthropogenic peatland in southern Chile

    Science.gov (United States)

    Perez-Quezada, J. F.; Brito, C. E.; Valdés, A.; Urrutia, P.

    2016-12-01

    Few studies have reported the effects of deforestation on carbon stocks and greenhouse gas balance in the temperate forests of the southern hemisphere. In some areas of southern Chile, after clear-cut or forest fires occurs a proliferation of Sphagnum moss, generating an anthropogenic type of peatland. We measured the effects of this change on the carbon stocks and the greenhouse gas balance, starting in 2013. Carbon stocks were measured in >30 plots on each site; ecosystem CO2 fluxes were measured continuously using eddy covariance stations; CH4 and N2O fluxes were measured monthly using closed chambers and cavity ring-down spectroscopy technology. Total ecosystem carbon stock was 1,523 Mg ha-1 in the forest and 130 Mg ha-1 in the peatland, representing a 91% difference. Both land use types were found to act as sinks of CO2 (NEE=-1094.2 and -31.9 g CO2 m-2 year-¹ for the forest and peatland, respectively); CH4 was mainly captured in the forest and peatland soils, generating balances of -0.70 and -0.12 g CH₄ m-2 year-¹. N2O fluxes were extremely low, so were considered as null. These results indicate that the greenhouse gas balance moved from -1134.6 to -38.8 g CO2-eq m-2 year-1 when land use changed from forest to anthropogenic peatland. These results provide evidence of the importance of preserving old-growth forests in southern Chile.

  7. Influence of spring phenology on seasonal and annual carbon balance in two contrasting New England forests.

    Science.gov (United States)

    Richardson, Andrew D; Hollinger, David Y; Dail, D Bryan; Lee, John T; Munger, J William; O'keefe, John

    2009-03-01

    Spring phenology is thought to exert a major influence on the carbon (C) balance of temperate and boreal ecosystems. We investigated this hypothesis using four spring onset phenological indicators in conjunction with surface-atmosphere CO(2) exchange data from the conifer-dominated Howland Forest and deciduous-dominated Harvard Forest AmeriFlux sites. All phenological measures, including CO(2) source-sink transition dates, could be well predicted on the basis of a simple two-parameter spring warming model, indicating good potential for improving the representation of phenological transitions and their dynamic responsiveness to climate variability in land surface models. The date at which canopy-scale photosynthetic capacity reached a threshold value of 12 micromol m(-2) s(-1) was better correlated with spring and annual flux integrals than were either deciduous or coniferous bud burst dates. For all phenological indicators, earlier spring onset consistently, but not always significantly, resulted in higher gross primary productivity (GPP) and ecosystem respiration (RE) for both seasonal (spring months, April-June) and annual flux integrals. The increase in RE was less than that in GPP; depending on the phenological indicator used, a one-day advance in spring onset increased springtime net ecosystem productivity (NEP) by 2-4 g C m(-2) day(-1). In general, we could not detect significant differences between the two forest types in response to earlier spring, although the response to earlier spring was generally more pronounced for Harvard Forest than for Howland Forest, suggesting that future climate warming may favor deciduous species over coniferous species, at least in this region. The effect of earlier spring tended to be about twice as large when annual rather than springtime flux integrals were considered. This result is suggestive of both immediate and lagged effects of earlier spring onset on ecosystem C cycling, perhaps as a result of accelerated N cycling

  8. Towards operational remote sensing of forest carbon balance across Northern Europe

    Directory of Open Access Journals (Sweden)

    P. Olofsson

    2008-05-01

    Full Text Available Monthly averages of ecosystem respiration (ER, gross primary production (GPP and net ecosystem exchange (NEE over Scandinavian forest sites were estimated using regression models driven by air temperature (AT, absorbed photosynthetically active radiation (APAR and vegetation indices. The models were constructed and evaluated using satellite data from Terra/MODIS and measured data collected at seven flux tower sites in northern Europe. Data used for model construction was excluded from the evaluation. Relationships between ground measured variables and the independent variables were investigated.

    It was found that the enhanced vegetation index (EVI at 250 m resolution was highly noisy for the coniferous sites, and hence, 1 km EVI was used for the analysis. Linear relationships between EVI and the biophysical variables were found: correlation coefficients between EVI and GPP, NEE, and AT ranged from 0.90 to 0.79 for the deciduous data, and from 0.85 to 0.67 for the coniferous data. Due to saturation, there were no linear relationships between normalized difference vegetation index (NDVI and the ground measured parameters found at any site. APAR correlated better with the parameters in question than the vegetation indices. Modeled GPP and ER were in good agreement with measured values, with more than 90% of the variation in measured GPP and ER being explained by the coniferous models. The site-specific respiration rate at 10°C (R10 was needed for describing the ER variation between sites. Even though monthly NEE was modeled with less accuracy than GPP, 61% and 75% (dec. and con., respectively of the variation in the measured time series was explained by the model. These results are important for moving towards operational remote sensing of forest carbon balance across Northern Europe.

  9. TOR Signaling Promotes Accumulation of BZR1 to Balance Growth with Carbon Availability in Arabidopsis.

    Science.gov (United States)

    Zhang, Zhenzhen; Zhu, Jia-Ying; Roh, Jeehee; Marchive, Chloé; Kim, Seong-Ki; Meyer, Christian; Sun, Yu; Wang, Wenfei; Wang, Zhi-Yong

    2016-07-25

    For maintenance of cellular homeostasis, the actions of growth-promoting hormones must be attenuated when nutrient and energy become limiting. The molecular mechanisms that coordinate hormone-dependent growth responses with nutrient availability remain poorly understood in plants [1, 2]. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates nutrient and energy signaling to regulate growth and homeostasis in both animals and plants [3-7]. Here, we show that sugar signaling through TOR controls the accumulation of the brassinosteroid (BR)-signaling transcription factor BZR1, which is essential for growth promotion by multiple hormonal and environmental signals [8-11]. Starvation, caused by shifting of light-grown Arabidopsis seedlings into darkness, as well as inhibition of TOR by inducible RNAi, led to plant growth arrest and reduced expression of BR-responsive genes. The growth arrest caused by TOR inactivation was partially recovered by BR treatment and the gain-of-function mutation bzr1-1D, which causes accumulation of active forms of BZR1 [12]. Exogenous sugar promoted BZR1 accumulation and seedling growth, but such sugar effects were largely abolished by inactivation of TOR, whereas the effect of TOR inactivation on BZR1 degradation is abolished by inhibition of autophagy and by the bzr1-1D mutation. These results indicate that cellular starvation leads sequentially to TOR inactivation, autophagy, and BZR1 degradation. Such regulation of BZR1 accumulation by glucose-TOR signaling allows carbon availability to control the growth promotion hormonal programs, ensuring supply-demand balance in plant growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. On the physical controls of the carbon dioxide balance at a high arctic site in Svalbard

    International Nuclear Information System (INIS)

    Lloyd, C.R.

    2001-01-01

    Current predictions of the effects of climate change indicate that the Arctic may experience a larger than average increase in temperature with consequent changes to the length of the snow-free active summer period, winter snow depth and amount and frequency of summer precipitation being highly probable. This paper reports on measurements of carbon dioxide flux at a high arctic site at Ny-Aalesund (78 o 56' N, 11 o 55' E), Svalbard and the physical climate variables that largely control this flux. lt is shown that during three important precipitation-free periods of the active summer period, namely post snow melt, high summer, and early autumn, the net balance between CO 2 flux from the soil (due to respiration of roots and soil organisms) and CO 2 assimilation by the vegetation is controlled largely by soil temperature and solar radiation. A simple combined photosynthetic assimilation-soil respiration model is shown to be capable of simulating the net CO 2 flux during mid-summer, but is less proficient in the post snow melt period and in early autumn when the simple models' inability to simulate the effects of emergent growth and ponding during the former and senescence, freezing temperatures and dew during the latter indicates the need for a more complex descriptive model. The net CO 2 flux during the measurement periods progresses from a net CO 2 source of 0.3 gC m -2 d -1 during late snow melt to a mid summer net CO 2 sink of -0.39 gC m -2 d -1 , returning to a net CO 2 source of 0.1 gC m -2 d -1 in the early autumn. Simple extrapolation of the data indicates that, during the active summer season in 1995, this site was a net sink of CO 2 of approximately -9 gC m -2 . (author)

  11. The carbon balance pivot point of southwestern U.S. semiarid ecosystems: Insights from the 21st century drought

    Science.gov (United States)

    Scott, Russell L.; Biederman, Joel A.; Hamerlynck, Erik P.; Barron-Gafford, Greg A.

    2015-12-01

    Global-scale studies indicate that semiarid regions strongly regulate the terrestrial carbon sink. However, we lack understanding of how climatic shifts, such as decadal drought, impact carbon sequestration across the wide range of structural diversity in semiarid ecosystems. Therefore, we used eddy covariance measurements to quantify how net ecosystem production of carbon dioxide (NEP) differed with relative grass and woody plant abundance over the last decade of drought in four Southwest U.S. ecosystems. We identified a precipitation "pivot point" in the carbon balance for each ecosystem where annual NEP switched from negative to positive. Ecosystems with grass had pivot points closer to the drought period precipitation than the predrought average, making them more likely to be carbon sinks (and a grass-free shrubland, a carbon source) during the current drought. One reason for this is that the grassland located closest to the shrubland supported higher leaf area and photosynthesis at the same water availability. Higher leaf area was associated with a greater proportion of evapotranspiration being transpiration (T/ET), and therefore with higher ecosystem water use efficiency (gross ecosystem photosynthesis/ET). Our findings strongly show that water availability is a primary driver of both gross and net semiarid productivity and illustrate that structural differences may contribute to the speed at which ecosystem carbon cycling adjusts to climatic shifts.

  12. Carbon balance of a plastic mulch and drip irrigated cotton field in an arid oasis of Northwest China

    Science.gov (United States)

    Ming, G.

    2017-12-01

    Carbon balance of a plastic mulch and drip irrigated cotton field in an arid oasis of Northwest ChinaGuanghui Ming1, Fuqiang Tian1*, Hongchang Hu11State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, China,Abstracts: Agricultural ecosystems have the potential to offset rising CO2 concentration in the atmosphere but the potential is often altered by agricultural management. Plastic film mulching and drip irrigation (PMDI) have been widespread for saving water and improving crop yield worldwide. To comprehensively assess the carbon balance and to detect the controlling factors of the carbon flux in a PMDI cotton field, experiments combining eddy covariance (EC) system, chamber method and crop sampling were implemented in an arid oasis of Xinjiang from the year 2012 to 2016. The annual net ecosystem exchange (NEE) was -250.18 ± 80.41 g C m-2 in the five years, which indicated that the filed was a much stronger carbon sink. After removal of the harvest of cotton as seed oil (Ch) of 108.81±7.57 g C m-2, the field was still a moderate carbon sink with net biome productivity (NBP) of 141.37±73.7 g C m-2. Soil temperature can explain 82% of seasonal variation of nighttime NEE while PAR can explain 36-81% of daytime NEE varying with crop development and photosynthetic activity. NEE was separated into total ecosystem respiration (Reco, 1214.20±144.42 g C m-2) and gross primary productivity (GPP, 1464.38±122.78 g C m-2). Interannual Reco changed more drastically than GPP and respiration may be the main determinant of carbon balance in the PMDI field. Seasonal NPP measured by cop sampling method (NPPCS) agreed well with NPP calculated with EC (NPPEC), with the annual NPP of 708.86 ± 52.26 g C m-2, which indicated that our carbon flux measurements and separating methods reasonable. The PMDI cotton field induced more GPP and Reco than other croplands with larger light use efficiency (LUE) but relatively

  13. Social assessment of wind power. Part 3: Employment and balance of payments

    International Nuclear Information System (INIS)

    Munksgaard, J.; Rahbaek Pedersen, J.; Jensen, T.

    1995-12-01

    The main object of this report is to investigate the consequences of a wind power development of the Danish electricity system on employment and the balance of payments. The development is carried out as an investment in 1,000 MW wind power compared to a 450 MW coal-based central power plant. The wind power development is consistent with 'Energy 2000 - A Plan of Action for Sustainable Development' from the Danish Ministry of Energy which states that a total capacity of 1,500 MW should be reached by 2005. The effects on the employment and the balance of payments will be quantified as employed per year and million DKK per year respectively. This is due to the opinion that these effects should not have decisive influence on the assessment of long term energy and environmental projects. Based on the assumptions on the cost-efficiency of wind power the capacity of 1,000 MW wind power, supplied by 220 MW backup capacity from natural gas-fired turbines, is equivalent to a 420 MW central power plant base on coal. This forms the basis of two scenarios: a wind power scenario and a coal power scenario. The overall result in this report is that the effects on employment and the balance of payments do not differ very much. Therefore one cannot recommend nor reject wind power in the Danish electricity system compared to a coal-based central power plant. (EG) 13 refs

  14. A review of carbon and nitrogen balances in switchgrass grown for energy

    International Nuclear Information System (INIS)

    Bransby, D.I.; McLaughlin, S.B.; Parrish, D.J.

    1998-01-01

    Increased atmospheric CO 2 caused partly by burning fossil fuels, is assumed to elevate the risk of global warming, while nitrate contamination of surface runoff and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO 2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration, and reduce NO 3 -1 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in filter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature, unpublished data and on-going research. Replacing fossil fuels with switchgrass, or any other biomass, will have a much greater effect on atmospheric CO 2 than C sequestration. This is because replacing fossil fuels provides a cumulative effect, while C sequestration offers only a one-time benefit. Furthermore, switchgrass will provide net gains in C sequestration only if it replaces annual row crops, but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%, which compares favorably with the 50% recovery frequently quoted as the norm for wheat (Triticum aestivum L.) and corn (Zea mays L.). (Author)

  15. Matters of Cost: Part I. Jones Learns about Balance Sheets: Part II. A Look at Budgetary Control: Part III. The Supervisor's "Do-It-Yourself" Series 3.

    Science.gov (United States)

    Smith, J. E.; And Others

    This guide, which is intended for new supervisors and managers to use in an independent study setting, deals with costing, balance sheets, and budgetary control. The first section, "Matters of Cost" by J. E. and J. F. Smith, deals with the following topics: profits and productivity, principles of costing, cost control and cost reduction, fixed and…

  16. Carbon dioxide emissions and energy balance closure before, during, and after biomass burning in mid-South rice fields

    Science.gov (United States)

    Fong, B.; Adviento-Borbe, A.; Reba, M. L.; Runkle, B.; Suvocarev, K.

    2017-12-01

    Biomass burning or field burning is a crop management practice that removes rice straw, reduces tillage, controls pests and releases nutrients for the next cropping season. Current field burning emissions are not included in agricultural field annual emissions largely because of the lack of studies, especially on the field scale. Field burning measurements are important for greenhouse gas emission inventories and quantifying the annual carbon footprint of rice. Paired eddy covariance systems were used to measure energy balance, CO2 fluxes, and H2O fluxes in mid-South US rice fields (total area of 25 ha) before, during and after biomass burning for 20 days after harvest. During the biomass burning, air temperatures increased 29°C, while ambient CO2 concentration increased from 402 to 16,567 ppm and H2O concentrations increased from 18.73 to 25.62 ppt. For the burning period, 67-86 kg CO2 ha-1 period-1 was emitted calculated by integrating fluxes over the biomass burning event. However, the estimated emission using aboveground biomass and combustion factors was calculated as 11,733 kg CO2 ha-1 period-1. Part of the difference could be attributed to sensor sensitivity decreasing 80% during burning for two minutes due to smoke. Net ecosystem exchange (NEE) increased by a factor of two, 1.14 before burning to 2.44 μmol m-2 s-1 possibly due to greater reduction of plant material and photosynthesis following burning. This study highlights the contribution of rice straw burning to total CO2 emissions from rice production.

  17. Clinical pharmacy academic career transitions: Viewpoints from the field Part 2: Understanding and balancing the distribution of effort.

    Science.gov (United States)

    Thompson, Angela; Blackmer, Allison; Jeffres, Meghan; Glode, Ashley; Mahyari, Nila; Thompson, Megan

    2018-02-01

    The six authors of this commentary series, who have recently transitioned into or within an academic career, discuss challenging aspects of an academic career change. The authors represent faculty members teaching within a large, state-funded, research-intensive School of Pharmacy located within a large academic health center. The authors have various backgrounds and represent individuals making transitions at various points in their careers (from residency into academia, from a non-academic environment into academia, and from one academic environment to another). This is Part 2 of a three-part commentary series that focuses on understanding and balancing the distribution of effort. Parts 1 and 3 of this commentary series explore feedback, evaluation and advancement; and learning when and how to say yes, respectively. While the entire series is intended to be read in continuity, faculty, or those interested in pursuing a career in pharmacy academia, can refer to Part 2 as a reference to aid in understanding and balancing the different components and the distribution of effort associated with a position in academic pharmacy, specifically. Schools of Pharmacy may utilize this as a tool for new faculty members during orientation in order to help ensure faculty success. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Modelling system dynamics and phytoplankton diversity at Ranchi lake using the carbon and nutrient mass balance equations.

    Science.gov (United States)

    Mukherjee, B; Nivedita, M; Mukherjee, D

    2014-05-01

    Modelling system dynamics in a hyper-eutrophic lake is quite complex especially with a constant influx of detergents and sewage material which continually changes the state variables and interferes with the assessment of the chemical rhythm occurring in polluted conditions as compared to unpolluted systems. In this paper, a carbon and nutrient mass balance model for predicting system dynamics in a complex environment was studied. Studies were conducted at Ranchi lake to understand the altered environmental dynamics in hyper-eutrophic conditions, and its impact on the plankton community. The lake was monitored regularly for five years (2007 - 2011) and the data collected on the carbon flux, nitrates, phosphates and silicates was used to design a mass balance model for evaluating and predicting the system. The model was then used to correlate the chemical rhythm with that of the phytoplankton dynamics and diversity. Nitrates and phosphates were not limiting (mean nitrate and phosphate concentrations were 1.74 and 0.83 mgl⁻¹ respectively). Free carbon dioxide was found to control the system and, interacting with other parameters determined the diversity and dynamics of the plankton community. N/P ratio determined which group of phytoplankton dominated the community, above 5 it favoured the growth of chlorophyceae while below 5 cyanobacteria dominates. TOC/TIC ratio determined the abundance. The overall system was controlled by the availability of free carbon dioxide which served as a limiting factor.

  19. Nutritional balance of pigs irradiated on the hind part with 1100 rd of 60Co gamma rays

    International Nuclear Information System (INIS)

    Daburon, F.; Tricaud, Y.; Bourhoven, D.; Marion, C.

    1978-01-01

    The hind part of 10 adult miniature pigs was irradiated with 1100 rd of 60 Co gamma rays. The dietary mineral (Na, K, Ca, P), nitrogen and lipid balances of the animals were studied before and 1, 3 and 5 months after irradiation. While the classical early lesion of the intestinal mucosa recovered quite satisfactorily within one or two months, a pancreatic atrophy process developed progressively which might play a major role in the nutritional state of the pigs and thus in their survival. Concerning nutritional balance, nitrogen and sodium retention were perturbed until 5 months post-irradiation; cyanocobalamin absorption remained very low. Dry and organic matter utilization recovered nearly normal values in the 3rd ou 5th month [fr

  20. The CarbonTracker Data Assimilation Shell (CTDAS) v1.0: implementation and global carbon balance 2001-2015

    Science.gov (United States)

    van der Laan-Luijkx, Ingrid T.; van der Velde, Ivar R.; van der Veen, Emma; Tsuruta, Aki; Stanislawska, Karolina; Babenhauserheide, Arne; Zhang, Hui Fang; Liu, Yu; He, Wei; Chen, Huilin; Masarie, Kenneth A.; Krol, Maarten C.; Peters, Wouter

    2017-07-01

    Data assimilation systems are used increasingly to constrain the budgets of reactive and long-lived gases measured in the atmosphere. Each trace gas has its own lifetime, dominant sources and sinks, and observational network (from flask sampling and in situ measurements to space-based remote sensing) and therefore comes with its own optimal configuration of the data assimilation. The CarbonTracker Europe data assimilation system for CO2 estimates global carbon sources and sinks, and updates are released annually and used in carbon cycle studies. CarbonTracker Europe simulations are performed using the new modular implementation of the data assimilation system: the CarbonTracker Data Assimilation Shell (CTDAS). Here, we present and document this redesign of the data assimilation code that forms the heart of CarbonTracker, specifically meant to enable easy extension and modification of the data assimilation system. This paper also presents the setup of the latest version of CarbonTracker Europe (CTE2016), including the use of the gridded state vector, and shows the resulting carbon flux estimates. We present the distribution of the carbon sinks over the hemispheres and between the land biosphere and the oceans. We show that with equal fossil fuel emissions, 2015 has a higher atmospheric CO2 growth rate compared to 2014, due to reduced net land carbon uptake in later year. The European carbon sink is especially present in the forests, and the average net uptake over 2001-2015 was 0. 17 ± 0. 11 PgC yr-1 with reductions to zero during drought years. Finally, we also demonstrate the versatility of CTDAS by presenting an overview of the wide range of applications for which it has been used so far.

  1. FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS - part II: GRAPHENE

    Directory of Open Access Journals (Sweden)

    Cătălin IANCU

    2012-05-01

    Full Text Available As was presented in the first part of this review paper, lately, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. In this review paper are presented some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. In this part of the paper are presented the synthesis techniques used to produce the two-dimensional carbon nanomaterials (including graphene, and also the most important properties and potential applications of graphene.

  2. Balancing Optimal Assessment with Part-Time Faculty Participation: A Discipline's Dilemma

    Science.gov (United States)

    Danley-Scott, Jennifer; Tompsett-Makin, Deborah

    2013-01-01

    Part-time faculty need to be brought into the student learning outcomes assessment loop not only to help accreditation, but because they, like full-time faculty, can benefit from assessment. When part-time faculty are not participating in assessment, a sizable percentage of courses are being less effectively taught than they could be. In an…

  3. [Analysis of carbon balance and study on mechanism in anoxic-oxic-settling-anaerobic sludge reduction process].

    Science.gov (United States)

    Zhai, Xiao-Min; Gao, Xu; Zhang, Man-Man; Jia, Li; Guo, Jin-Song

    2012-07-01

    In order to deeply explore the mechanism of sludge reduction in OSA system, carbon balance was performed in an anoxic-oxic-settling-anaerobic (A + OSA) system and a reference AO system to investigate effects of inserting a sludge holding tank in sludge cycle line on the sludge reduction process. Meanwhile, carbon mass change in each reaction unit was identified in terms of solid, liquid and gas phases. The causes of excess sludge reduction in A + OSA system were deduced. The carbon balance results show that when the hydraulic retention time in the sludge holding tank is 7.14 h, carbon percent in solid phase of the sludge reduction system is nearly 50% higher than that of the reference system, supporting the consequence that sludge reduction rate of 49.98% had been achieved. The insertion of a sludge holding tank in the sludge return circuit can be effective in sludge reduction. Carbon changes in each unit reveal that the amount of carbon consumed for biosynthesis in the anoxic and oxic tanks (main reaction zone) of the sludge reduction system is higher than in that of the reference system. Sludge decay is observed in the sludge holding tank. Furthermore, CH4 released from the sludge holding tank is significantly higher than that from the main reaction zone. The DGGE profiles show that there are hydrolytic-fermentative bacteria in the sludge holding tank related to sludge decay. The excess sludge reduction in the A + OSA system could be a result of the combination of sludge decay in the sludge holding tank and sludge compensatory growth in the main reaction cell.

  4. Total Belowground Carbon Allocation in a Fast-growing Eucalyptus Plantation Estimated Using a Carbon Balance Approach

    Science.gov (United States)

    Christian P. Giardina; Michael G. Ryan

    2002-01-01

    Trees allocate a large portion of gross primary production belowground for the production and maintenance of roots and mycorrhizae. The difficulty of directly measuring total belowground carbon allocation (TBCA) has limited our understanding of belowground carbon (C) cycling and the factors that control this important flux. We measured TBCA over 4 years using a...

  5. Carbon dioxide stripping in aquaculture -- part III: model verification

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    Based on conventional mass transfer models developed for oxygen, the use of the non-linear ASCE method, 2-point method, and one parameter linear-regression method were evaluated for carbon dioxide stripping data. For values of KLaCO2 < approximately 1.5/h, the 2-point or ASCE method are a good fit to experimental data, but the fit breaks down at higher values of KLaCO2. How to correct KLaCO2 for gas phase enrichment remains to be determined. The one-parameter linear regression model was used to vary the C*CO2 over the test, but it did not result in a better fit to the experimental data when compared to the ASCE or fixed C*CO2 assumptions.

  6. Historical and projected carbon balance of mature black spruce ecosystems across north america: The role of carbon-nitrogen interactions

    Science.gov (United States)

    Clein, Joy S.; McGuire, A.D.; Zhang, X.; Kicklighter, D.W.; Melillo, J.M.; Wofsy, S.C.; Jarvis, P.G.; Massheder, J.M.

    2002-01-01

    The role of carbon (C) and nitrogen (N) interactions on sequestration of atmospheric CO2 in black spruce ecosystems across North America was evaluated with the Terrestrial Ecosystem Model (TEM) by applying parameterizations of the model in which C-N dynamics were either coupled or uncoupled. First, the performance of the parameterizations, which were developed for the dynamics of black spruce ecosystems at the Bonanza Creek Long-Term Ecological Research site in Alaska, were evaluated by simulating C dynamics at eddy correlation tower sites in the Boreal Ecosystem Atmosphere Study (BOREAS) for black spruce ecosystems in the northern study area (northern site) and the southern study area (southern site) with local climate data. We compared simulated monthly growing season (May to September) estimates of gross primary production (GPP), total ecosystem respiration (RESP), and net ecosystem production (NEP) from 1994 to 1997 to available field-based estimates at both sites. At the northern site, monthly growing season estimates of GPP and RESP for the coupled and uncoupled simulations were highly correlated with the field-based estimates (coupled: R2= 0.77, 0.88 for GPP and RESP; uncoupled: R2 = 0.67, 0.92 for GPP and RESP). Although the simulated seasonal pattern of NEP generally matched the field-based data, the correlations between field-based and simulated monthly growing season NEP were lower (R2 = 0.40, 0.00 for coupled and uncoupled simulations, respectively) in comparison to the correlations between field-based and simulated GPP and RESP. The annual NEP simulated by the coupled parameterization fell within the uncertainty of field-based estimates in two of three years. On the other hand, annual NEP simulated by the uncoupled parameterization only fell within the field-based uncertainty in one of three years. At the southern site, simulated NEP generally matched field-based NEP estimates, and the correlation between monthly growing season field-based and

  7. The impact of sheep grazing on the carbon balance of a peatland

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, Fred, E-mail: Fred.Worrall@durham.ac.uk; Clay, Gareth D.

    2012-11-01

    Estimates of the greenhouse gas (GHG) fluxes resulting from sheep grazing upon upland peat soils have never been fully quantified. Previous studies have been limited to individual flux pathways or to comparing the presence to the absence of sheep grazing. Therefore, this study combines a model of the physical impact of grazing with models of: biomass production; energy usage in sheep; and peat accumulation. These combined modelling approaches enabled this study to consider the indirect and direct impacts of sheep upon the carbon and greenhouse gas balance of a peatland at different grazing intensities as well as the changes between grazing intensities. The study considered four vegetation scenarios (Calluna sp., Molinia sp.; reseeded grasses, and Agrostis-Festuca grassland) and a mixed vegetation scenario based upon the vegetation typical of upland peat ecosystems in northern England. Each scenario was considered for altitudes between 350 and 900 m above sea level and for grazing intensities between 0.1 and 2 ewes/ha. The study can show that the total GHG flux at the vegetative carrying capacity tended to decline with increasing altitude for all vegetation scenarios considered except for Molinia sp. The average total GHG flux for all scenarios was 1505 kg CO{sub 2}eq/ha/yr/(ewe/ha), and on average 89% of the fluxes were directly from the sheep and not from the soil, and are therefore not unique to a peat soil environment. The study suggests that emission factors for upland sheep have been greatly underestimated. By comparing the total flux due to grazers to the flux to or from the soil that allows the study to define a GHG carry capacity, i.e. the grazing intensity at which the flux due to grazing is equal to the sink represented by the peat soils, this GHG carrying capacity varies between 0.2 and 1.7 ewes/ha with this capacity declining with increasing altitude for all model scenarios. -- Highlights: Black-Right-Pointing-Pointer Vegetative carrying capacity was

  8. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    Science.gov (United States)

    Vanderdeelen, Jan

    2012-06-01

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO3 types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO3. H2O), the hexahydrate ikaite (CaCO3.6H2O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  9. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    International Nuclear Information System (INIS)

    De Visscher, Alex; Vanderdeelen, Jan

    2012-01-01

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO 3 types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO 3 · H 2 O), the hexahydrate ikaite (CaCO 3 ·6H 2 O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  10. IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

    Energy Technology Data Exchange (ETDEWEB)

    De Visscher, Alex; Vanderdeelen, Jan [Department of Chemical and Petroleum Engineering, and Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada); Department of Applied Analytical and Physical Chemistry, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent (Belgium)

    2012-06-15

    The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO{sub 3} types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO{sub 3}{center_dot} H{sub 2}O), the hexahydrate ikaite (CaCO{sub 3}{center_dot}6H{sub 2}O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

  11. Indoor and outdoor urban atmospheric CO2: Stable carbon isotope constraints on mixing and mass balance

    International Nuclear Information System (INIS)

    Yanes, Yurena; Yapp, Crayton J.

    2010-01-01

    Research highlights: → 13 C of indoor CO 2 indicates proportion of C 4 -derived carbon in occupants' diet. → Flux balance model for ventilated rooms shows rapid approach to CO 2 steady-state. → From extant indoor CO 2 data more dietary C 4 carbon in American than European diets. → Local outdoor urban CO 2 increase of 17 ppm in ten years, no change in average 13 C. - Abstract: From July to November 2009, concentrations of CO 2 in 78 samples of ambient air collected in 18 different interior spaces on a university campus in Dallas, Texas (USA) ranged from 386 to 1980 ppm. Corresponding δ 13 C values varied from -8.9 per mille to -19.4 per mille. The CO 2 from 22 samples of outdoor air (also collected on campus) had a more limited range of concentrations from 385 to 447 ppm (avg. = 408 ppm), while δ 13 C values varied from -10.1 per mille to -8.4 per mille (avg.=-9.0 per mille). In contrast to ambient indoor and outdoor air, the concentrations of CO 2 exhaled by 38 different individuals ranged from 38,300 to 76,200 ppm (avg. = 55,100 ppm), while δ 13 C values ranged from -24.8 per mille to -17.7 per mille (avg. = -21.8 per mille). The residence times of the total air in the interior spaces of this study appear to have been on the order of 10 min with relatively rapid approaches (∼30 min) to steady-state concentrations of ambient CO 2 gas. Collectively, the δ 13 C values of the indoor CO 2 samples were linearly correlated with the reciprocal of CO 2 concentration, exhibiting an intercept of -21.8 per mille, with r 2 = 0.99 and p 2 data representing 18 interior spaces (with varying numbers of occupants), and the coincidence of the intercept (-21.8 per mille) with the average δ 13 C value for human-exhaled CO 2 demonstrates simple mixing between two inputs: (1) outdoor CO 2 introduced to the interior spaces by ventilation systems, and (2) CO 2 exhaled by human occupants of those spaces. If such simple binary mixing is a common feature of interior spaces, it

  12. Earthworms and the soil greenhouse gas balance

    NARCIS (Netherlands)

    Lubbers, I.M.

    2014-01-01

    Earthworms play an essential part in determining the greenhouse gas (GHG) balance of soils worldwide. Their activity affects both biotic and abiotic soil properties, which in turn influence soil GHG emissions, carbon (C) sequestration and plant growth. Yet, the balance of earthworms

  13. Carbon Mobilization in Oil Palm Plantation and Milling Based on a Carbon-Balanced Model – A Case Study in Thailand

    Directory of Open Access Journals (Sweden)

    Withida Patthanaissaranukool

    2011-07-01

    Full Text Available Damage to agricultural areas and household properties occurs more frequently all year round from extreme weather, which is believed to be due to climate change caused by the increase of greenhouse gases – particularly, CO2. In order to help reduce its concentration in the atmosphere, palm oil is a renewable energy which can be used for this purpose. In this study, the carbon mobilization of palm oil was investigated, from oil palm plantation process to the milling process, so as to determine the associated Carbon Equivalence (CE and the effects on human and land space. A carbon-balanced model (CBM is proposed herewith to indicate the main paths of carbon emission, fixation, and reduction. The net equivalent carbon emission was found to be 56 kg CE per ton of Crude Palm Oil (CPO produced, resulting in the emission flux of 175 kg CE/ha-y. The plantation activity that emits the highest CO2 levels is fertilizer application, accounting for about 84% of the total. All bio-residues produced from CPO production were found to be utilized for human use, thereby decreasing the carbon emission. Their use ranged from biogas and electricity generation to soil conditioning, and the utilization of the bio-residues resulted in total carbon reduction of 212 kg CE per ton of CPO. Carbon fixation as a main product (CPO was found to be an average of 812 kg CE per ton of CPO, equivalent to 2543 kg CE/ha-y. Overall, as the total fixation is 14 times higher than that of the total emissions, the production of CPO generates and introduces a very small amount of waste into the environment. To satisfy the need for palm oil as renewable energy and other end-user products the expansion of the plantation areas may result in competition of agricultural land with other cash crops.

  14. Mississippi burnout part II: satisfaction, autonomy and work/family balance.

    Science.gov (United States)

    Cossman, Jeralynn S; Street, Debra

    2009-10-01

    Documented Mississippi physician shortages' make evidence about factors shaping physicians' career choices especially important if Mississippi policymakers are to devise workable strategies to maximize the physician workforce. Work-life interactions influence physicians' choices about how they manage their careers and professional burnout is one documented cause of physicians' decisions to change work hours or to choose early retirement. We find that women and mid-career physicians are more likely than men or later career physicians to experience stress and burnout. Additionally, physicians who experience burnout are less likely to report being satisfied with nearly every aspect of their professional life and work-life balance indicating that burnout permeates several dimensions of physicians' lives. The associations in our findings are suggestive; however, to minimize deleterious effects of burnout on the Mississippi physician workforce, future research should examine the causal factors underlying stress and burnout.

  15. In search of work/life balance: trainee perspectives on part-time obstetrics and gynaecology specialist training

    Directory of Open Access Journals (Sweden)

    Henry Amanda

    2012-01-01

    Full Text Available Abstract Background Part-time training (PTT is accessed by approximately 10% of Australian obstetrics and gynaecology trainees, a small but increasing minority which reflects the growing demand for improved work/life balance amongst the Australian medical workforce. This survey reports the attitudes and experiences of both full-time and part-time trainees to PTT. Methods An email-based anonymous survey was sent to all Australian obstetrics and gynaecology trainees in April 2009, collecting demographic and training status data, data on personal experiences of PTT and/or trainees, and attitudes towards PTT. Results 105 responses were received (20% response rate. These indicated strong support (90% from both full-time (FT and part-time (PT trainees for the availability of PTT. PT trainees were significantly more likely than FT trainees to be female with children. Improved morale was seen as a particular advantage of PTT; decreased continuity of care as a disadvantage. Conclusions Although limited by poor response rate, both PT and FT Australian obstetric trainees were supportive of part-time training. Both groups recognised important advantages and disadvantages of this mode of training. Currently, part-time training is accessed primarily by female trainees with family responsibilities, with many more trainees considering part-time training than the number that access it.

  16. In search of work/life balance: trainee perspectives on part-time obstetrics and gynaecology specialist training.

    Science.gov (United States)

    Henry, Amanda; Clements, Sarah; Kingston, Ashley; Abbott, Jason

    2012-01-10

    Part-time training (PTT) is accessed by approximately 10% of Australian obstetrics and gynaecology trainees, a small but increasing minority which reflects the growing demand for improved work/life balance amongst the Australian medical workforce. This survey reports the attitudes and experiences of both full-time and part-time trainees to PTT. An email-based anonymous survey was sent to all Australian obstetrics and gynaecology trainees in April 2009, collecting demographic and training status data, data on personal experiences of PTT and/or trainees, and attitudes towards PTT. 105 responses were received (20% response rate). These indicated strong support (90%) from both full-time (FT) and part-time (PT) trainees for the availability of PTT. PT trainees were significantly more likely than FT trainees to be female with children. Improved morale was seen as a particular advantage of PTT; decreased continuity of care as a disadvantage. Although limited by poor response rate, both PT and FT Australian obstetric trainees were supportive of part-time training. Both groups recognised important advantages and disadvantages of this mode of training. Currently, part-time training is accessed primarily by female trainees with family responsibilities, with many more trainees considering part-time training than the number that access it.

  17. Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene

    Science.gov (United States)

    Zhu, Zhengju; Jiang, Hao; Guo, Shaojun; Cheng, Qilin; Hu, Yanjie; Li, Chunzhong

    2015-10-01

    Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1 nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256 F g-1 at 1 A g-1 with excellent rate capability (120 F g-1 at 50 A g-1) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1 M H2SO4. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10 s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems.

  18. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-06-24

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  19. Soils apart from equilibrium – consequences for soil carbon balance modelling

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2007-01-01

    Full Text Available Many projections of the soil carbon sink or source are based on kinetically defined carbon pool models. Para-meters of these models are often determined in a way that the steady state of the model matches observed carbon stocks. The underlying simplifying assumption is that observed carbon stocks are near equilibrium. This assumption is challenged by observations of very old soils that do still accumulate carbon. In this modelling study we explored the consequences of the case where soils are apart from equilibrium. Calculation of equilibrium states of soils that are currently accumulating small amounts of carbon were performed using the Yasso model. It was found that already very small current accumulation rates cause big changes in theoretical equilibrium stocks, which can virtually approach infinity. We conclude that soils that have been disturbed several centuries ago are not in equilibrium but in a transient state because of the slowly ongoing accumulation of the slowest pool. A first consequence is that model calibrations to current carbon stocks that assume equilibrium state, overestimate the decay rate of the slowest pool. A second consequence is that spin-up runs (simulations until equilibrium overestimate stocks of recently disturbed sites. In order to account for these consequences, we propose a transient correction. This correction prescribes a lower decay rate of the slowest pool and accounts for disturbances in the past by decreasing the spin-up-run predicted stocks to match an independent estimate of current soil carbon stocks. Application of this transient correction at a Central European beech forest site with a typical disturbance history resulted in an additional carbon fixation of 5.7±1.5 tC/ha within 100 years. Carbon storage capacity of disturbed forest soils is potentially much higher than currently assumed. Simulations that do not adequately account for the transient state of soil carbon stocks neglect a considerable

  20. Implications of elevated CO2 on pelagic carbon fluxes in an Arctic mesocosm study – an elemental mass balance approach

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2013-05-01

    Full Text Available Recent studies on the impacts of ocean acidification on pelagic communities have identified changes in carbon to nutrient dynamics with related shifts in elemental stoichiometry. In principle, mesocosm experiments provide the opportunity of determining temporal dynamics of all relevant carbon and nutrient pools and, thus, calculating elemental budgets. In practice, attempts to budget mesocosm enclosures are often hampered by uncertainties in some of the measured pools and fluxes, in particular due to uncertainties in constraining air–sea gas exchange, particle sinking, and wall growth. In an Arctic mesocosm study on ocean acidification applying KOSMOS (Kiel Off-Shore Mesocosms for future Ocean Simulation, all relevant element pools and fluxes of carbon, nitrogen and phosphorus were measured, using an improved experimental design intended to narrow down the mentioned uncertainties. Water-column concentrations of particulate and dissolved organic and inorganic matter were determined daily. New approaches for quantitative estimates of material sinking to the bottom of the mesocosms and gas exchange in 48 h temporal resolution as well as estimates of wall growth were developed to close the gaps in element budgets. However, losses elements from the budgets into a sum of insufficiently determined pools were detected, and are principally unavoidable in mesocosm investigation. The comparison of variability patterns of all single measured datasets revealed analytic precision to be the main issue in determination of budgets. Uncertainties in dissolved organic carbon (DOC, nitrogen (DON and particulate organic phosphorus (POP were much higher than the summed error in determination of the same elements in all other pools. With estimates provided for all other major elemental pools, mass balance calculations could be used to infer the temporal development of DOC, DON and POP pools. Future elevated pCO2 was found to enhance net autotrophic community carbon

  1. Energy balance and flow in steam generator part with sodium-water reaction

    International Nuclear Information System (INIS)

    Matal, O.

    1980-01-01

    Relations were derived for the calculation of heat liberated during the sodium water reaction in a tube failure in different parts of a steam generator. The results are graphically shown in i-T diagrams. Heat removal is described from the reaction zone to water and steam in undisturbed tubes and to the steam generator metal structure. (author)

  2. Modelling effects of forest disturbance history on carbon balance: a deep learning approach using Landsat-time series.

    Science.gov (United States)

    Besnard, S.; Carvalhais, N.; Clevers, J.; Dutrieux, L.; Gans, F.; Herold, M.; Reichstein, M.; Jung, M.

    2017-12-01

    Forests play a crucial role in the global carbon (C) cycle, covering about 30% of the planet's terrestrial surface, accounting for 50% of plant productivity, and storing 45% of all terrestrial C. As such, forest disturbances affect the balance of terrestrial C dioxide (CO 2 ) exchange, with the potential of releasing large amounts of C into the atmosphere. Understanding and quantifying the effect of forest disturbance on terrestrial C metabolism is critical for improving forest C balance estimates and predictions. Here we combine remote sensing, climate, and eddy-covariance (EC) data to study forest land surface-atmosphere C fluxes at more than 180 sites globally. We aim to enhance understanding of C balance in forest ecosystems by capturing the ecological carry-over effect of disturbance historyon C fluxes. Our objectives are to (1) characterize forest disturbance history through the full temporal depth of the Landsat time series (LTS); and (2) to investigate lag and carry-over effects of forest dynamics and climate on ecosystem C fluxes using a data-driven recurrent neural network(RNN). The resulting data-driven model integrates carry-over effects of the system, using LTS, ecosystem productivity, and several abiotic factors. In this study, we show that our RNN algorithm is able to effectively calculate realistic seasonal, interannual, and across-site C flux variabilities based on EC, LTS, and climate data. In addition, our results demonstrate that a deep learning approach with embedded dynamic memory effects offorest dynamics is able to better capture lag and carry-over effects due to soil-vegetation feedback compared to a classic approach considering only the current condition of the ecosystem. Our study paves the way to produce accurate, high resolution carbon fluxes maps, providing morecomprehensive monitoring, mapping, and reporting of the carbon consequences of forest change globally.

  3. Development of a Method for Measuring Carbon Balance in Chemical Sequestration of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongxian; Pan, Wei-Ping; Riley, John T.

    2006-09-09

    Anthropogenic CO2 released from fossil fuel combustion is a primary greenhouse gas which contributes to “global warming.” It is estimated that stationary power generation contributes over one-third of total CO2 emissions. Reducing CO2 in the atmosphere can be accomplished either by decreasing the rate at which CO2 is emitted into the atmosphere or by increasing the rate at which it is removed from it. Extensive research has been conducted on determining a fast and inexpensive method to sequester carbon dioxide. These methods can be classified into two categories, CO2 fixation by natural sink process for CO2, or direct CO2 sequestration by artificial processes. In direct sequestration, CO2 produced from sources such as coal-fired power plants, would be captured from the exhausted gases. CO2 from a combustion exhaust gas is absorbed with an aqueous ammonia solution through scrubbing. The captured CO2 is then used to synthesize ammonium bicarbonate (ABC or NH4HCO3), an economical source of nitrogen fertilizer. In this work, we studied the carbon distribution after fertilizer is synthesized from CO2. The synthesized fertilizer in laboratory is used as a “CO2 carrier” to “transport” CO2 from the atmosphere to crops. After biological assimilation and metabolism in crops treated with ABC, a considerable amount of the carbon source is absorbed by the plants with increased biomass production. The majority of the unused carbon source percolates into the soil as carbonates, such as calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). These carbonates are environmentally benign. As insoluble salts, they are found in normal rocks and can be stored safely and permanently in soil. This investigation mainly focuses on the carbon distribution after the synthesized fertilizer is applied to soil. Quantitative examination of carbon distribution in an ecosystem is a challenging task since the carbon in the soil may come from various sources. Therefore synthesized 14C

  4. Drought during canopy development has lasting effect on annual carbon balance in a deciduous temperate forest

    Science.gov (United States)

    Asko Noormets; Steve G. McNulty; Jared L. DeForest; Ge Sun; Qinglin Li; Jiquan Chen

    2008-01-01

    Climate change projections predict an intensifying hydrologic cycle and an increasing frequency of droughts, yet quantitative understanding of the effects on ecosystem carbon exchange remains limitedHere, the effect of contrasting precipitation and soil moisture dynamics were evaluated on forest carbon exchange using 2 yr of...

  5. Balancing Methane Emissions and Carbon Sequestration in Tropical/Subtropical Coastal Wetlands: A Review

    Science.gov (United States)

    Mitsch, W. J.; Schafer, K. V.; Cabezas, A.; Bernal, B.

    2016-02-01

    Wetlands are estimated to emit about 20 to 25 percent of current global CH4 emissions, or about 120 to 180 Tg-CH4 yr-1. Thus, in climate change discussions concerning wetlands, these "natural emissions" often receive the most attention, often overshadowing the more important ecosystem services that wetlands provide, including carbon sequestration. While methane emissions from coastal wetlands have generally been described as small due to competing biogeochemical cycles, disturbance of coastal wetlands, e.g., the introduction of excessive freshwater fluxes or substrate disturbance, can lead to much higher methane emission rates. Carbon sequestration is a more positive carbon story about wetlands and coastal wetlands in particular. The rates of carbon sequestration in tropical/subtropical coastal wetlands, mainly mangroves, are in the range of 100 to 200 g-C m-2 yr-1, two to ten times higher rates than in the more frequently studied northern peatlands. This function of coastal wetlands has significant international support now for mangrove conservation and it is referred to in the literature and popular press as blue carbon. This presentation will summarize what we know about methane emissions and carbon sequestration in tropical/subtropical coastal wetlands, how these rates compare with those in non-tropical and/or inland wetlands, and a demonstration of two or three models that compare methane fluxes with carbon dioxide sequestration to determine if wetlands are net sinks of radiative forcing. The presentation will also present a global model of carbon with an emphasis on wetlands.

  6. Estimation of Global 1km-grid Terrestrial Carbon Exchange Part II: Evaluations and Applications

    Science.gov (United States)

    Murakami, K.; Sasai, T.; Kato, S.; Niwa, Y.; Saito, M.; Takagi, H.; Matsunaga, T.; Hiraki, K.; Maksyutov, S. S.; Yokota, T.

    2015-12-01

    Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. Many studies have been trying to reveal distribution of carbon exchanges between terrestrial ecosystems and atmosphere for understanding global carbon cycle dynamics by using terrestrial biosphere models, satellite data, inventory data, and so on. However, most studies remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community and to evaluate the carbon stocks by forest ecosystems in each countries. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. We show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. The methodology for these estimations are shown in the 2015 AGU FM poster "Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling". In this study, we evaluated the carbon exchanges in various regions with other approaches. We used the satellite-driven biosphere model (BEAMS) as our estimations, GOSAT L4A CO2 flux data, NEP retrieved by NICAM and CarbonTracer2013 flux data, for period from Jun 2001 to Dec 2012. The temporal patterns for this period were indicated similar trends between BEAMS, GOSAT, NICAM, and CT2013 in many sub-continental regions. Then, we estimated the terrestrial carbon exchanges in each countries, and could indicated the temporal patterns of the exchanges in large carbon stock regions.Global terrestrial carbon cycle largely depends on a spatial pattern of land cover type, which is heterogeneously-distributed over regional and global scales. Many

  7. Competitive effect of KOH activation on the electrochemical performances of carbon nanotubes for EDLC: Balance between porosity and conductivity

    International Nuclear Information System (INIS)

    Xu Bin; Wu Feng; Su Yuefeng; Cao Gaoping; Chen Shi; Zhou Zhiming; Yang Yusheng

    2008-01-01

    This work is focused on the competitive effects on the performance of the electric double layer capacitors (EDLCs) between porosity increase and simultaneous conductivity decrease for KOH-activated carbon nanotubes (CNTs). A series of the CNTs have been activated with KOH to enhance their surface areas for application in EDLCs. The microstructure of the activated carbon nanotubes (ACNTs) is characterized with N 2 adsorption, transmission electron microscopy (TEM) observation and electric conductivity measurement. Their electrochemical performances are evaluated in aqueous KOH electrolyte with galvanostatic charge/discharge, cyclic voltammetry, and ac impedance spectroscopy. It is found that the KOH activation enhances the specific surface area of the CNTs and its specific capacitance but decreases its electric conductivity and the rate performance in EDLC. By controlling the activation of the CNTs to balance the porosity and conductivity, ACNTs with both high capacitance and good rate performance are obtained

  8. Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon

    DEFF Research Database (Denmark)

    Don, Axel; Osborne, Bruce; Hastings, Astley

    2012-01-01

    for Miscanthus). However, there was no positive or even negative effects on the C balance if energy crops are established on former grassland. Increased bioenergy production may also result in direct and indirect land-use changes with potential high C losses when native vegetation is converted to annual crops......Bioenergy from crops is expected to make a considerable contribution to climate change mitigation. However, bioenergy is not necessarily carbon neutral because emissions of CO2, N2O and CH4 during crop production may reduce or completely counterbalance CO2 savings of the substituted fossil fuels...... of lower fertilizer requirements as well as a higher N-use efficiency, due to effective N-recycling. Perennial energy crops have the potential to sequester additional carbon in soil biomass if established on former cropland (0.44 Mg soil C ha 1 yr 1 for poplar and willow and 0.66 Mg soil C ha 1 yr 1...

  9. Balancing carbon/nitrogen ratio to improve nutrients removal and algal biomass production in piggery and brewery wastewaters.

    Science.gov (United States)

    Zheng, Hongli; Liu, Mingzhi; Lu, Qian; Wu, Xiaodan; Ma, Yiwei; Cheng, Yanling; Addy, Min; Liu, Yuhuan; Ruan, Roger

    2018-02-01

    To improve nutrients removal from wastewaters and enhance algal biomass production, piggery wastewater was mixed with brewery wastewaters. The results showed that it was a promising way to cultivate microalga in piggery and brewery wastewaters by balancing the carbon/nitrogen ratio. The optimal treatment condition for the mixed piggery-brewery wastewater using microalga was piggery wastewater mixed with brewery packaging wastewater by 1:5 at pH 7.0, resulting in carbon/nitrogen ratio of 7.9, with the biomass concentration of 2.85 g L -1 , and the removal of 100% ammonia, 96% of total nitrogen, 90% of total phosphorus, and 93% of chemical oxygen demand. The application of the established strategies can enhance nutrient removal efficiency of the wastewaters while reducing microalgal biomass production costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Global modeling of land water and energy balances. Part III: Interannual variability

    Science.gov (United States)

    Shmakin, A.B.; Milly, P.C.D.; Dunne, K.A.

    2002-01-01

    The Land Dynamics (LaD) model is tested by comparison with observations of interannual variations in discharge from 44 large river basins for which relatively accurate time series of monthly precipitation (a primary model input) have recently been computed. When results are pooled across all basins, the model explains 67% of the interannual variance of annual runoff ratio anomalies (i.e., anomalies of annual discharge volume, normalized by long-term mean precipitation volume). The new estimates of basin precipitation appear to offer an improvement over those from a state-of-the-art analysis of global precipitation (the Climate Prediction Center Merged Analysis of Precipitation, CMAP), judging from comparisons of parallel model runs and of analyses of precipitation-discharge correlations. When the new precipitation estimates are used, the performance of the LaD model is comparable to, but not significantly better than, that of a simple, semiempirical water-balance relation that uses only annual totals of surface net radiation and precipitation. This implies that the LaD simulations of interannual runoff variability do not benefit substantially from information on geographical variability of land parameters or seasonal structure of interannual variability of precipitation. The aforementioned analyses necessitated the development of a method for downscaling of long-term monthly precipitation data to the relatively short timescales necessary for running the model. The method merges the long-term data with a reference dataset of 1-yr duration, having high temporal resolution. The success of the method, for the model and data considered here, was demonstrated in a series of model-model comparisons and in the comparisons of modeled and observed interannual variations of basin discharge.

  11. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    Science.gov (United States)

    Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Heumann, B. W.; Ramankutty, N.; Heimann, M.; Jones, C.

    2010-09-01

    European ecosystems are thought to take up large amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more that 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C yr-1. The extents of forest and grasslands have increased with the respective rates of 5800 km2 yr-1 and 1100 km2 yr-1 as agricultural land has been abandoned at a rate of 7000 km2 yr-1. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. The models suggest that European ecosystems sequester carbon at a rate of 56 TgC yr-1 (mean of four models for 1951-2000) with strong interannual variability (±88 TgC yr-1, average across models) and substantial inter-model uncertainty (±39 TgC yr-1). Decadal budgets suggest that there has been a continuous increase in the mean net carbon storage of ecosystems from 85 TgC yr-1 in 1980s to 108 TgC yr-1 in 1990s, and to 114 TgC yr-1 in 2000-2007. The physiological effect of rising CO2 in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are suggested as an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

  12. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    Directory of Open Access Journals (Sweden)

    G. Churkina

    2010-09-01

    land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

  13. Assessing Historical and Projected Carbon Balance of Alaska: A Synthesis of Results and Policy/Management Implications.

    Science.gov (United States)

    McGuire, A David; Genet, Hélène; Lyu, Zhou; Pastick, Neal; Stackpoole, Sarah; Birdsey, Richard; D'Amore, David; He, Yujie; Rupp, T Scott; Striegl, Robert; Wylie, Bruce K; Zhou, Xiaoping; Zhuang, Qianlai; Zhu, Zhiliang

    2018-06-20

    We summarize the results of a recent interagency assessment of land carbon dynamics in Alaska, in which carbon dynamics were estimated for all major terrestrial and aquatic ecosystems for the historical period (1950-2009) and a projection period (2010-2099). Between 1950 and 2009, upland and wetland (i.e., terrestrial) ecosystems of the State gained 0.4 Tg C yr -1 (0.1% of net primary production, NPP), resulting in a cumulative greenhouse gas radiative forcing of 1.68 x 10 -3 W m -2 . The change in carbon storage is spatially variable with the region of the Northwest Boreal Landscape Conservation Cooperative (LCC) losing carbon because of fire disturbance. The combined carbon transport via various pathways through inland aquatic ecosystems of Alaska was estimated to be 41.3 Tg C yr -1 (17% of terrestrial NPP). During the projection period (2010-2099), carbon storage of terrestrial ecosystems of Alaska was projected to increase (22.5 to 70.0 Tg C yr -1 ), primarily because of NPP increases of 10 to 30% associated with responses to rising atmospheric CO 2 , increased nitrogen cycling, and longer growing seasons. Although carbon emissions to the atmosphere from wildfire and wetland CH 4 were projected to increase for all of the climate projections, the increases in NPP more than compensated for those losses at the statewide level. Carbon dynamics of terrestrial ecosystems continue to warm the climate for four of the six future projections, and cool the climate for only one of the projections. The attribution analyses we conducted indicated that the response of NPP in terrestrial ecosystems to rising atmospheric CO 2 (~5% per 100 ppmv CO 2 ) saturates as CO 2 increases (between approximately +150 and +450 ppmv among projections). This response, along with the expectation that permafrost thaw would be much greater and release large quantities of permafrost carbon after 2100, suggests that projected carbon gains in terrestrial ecosystems of Alaska may not be sustained

  14. Research into falls of coal - part I. Investigacion en derrabes de carbon (1a parte)

    Energy Technology Data Exchange (ETDEWEB)

    Gomez de las Heras, J. (ITGE, Madrid (Spain))

    1991-10-01

    Summarises the work carried out between April 1989 and June 1991 as part of a research project into falls of coal in seams with a gradient greater than 35[degree]. The research centred on the coalfields of Castille, Leon and Asturias. The value of the project was 90 million pesetas. 6 figs., 2 tabs.

  15. Experimental investigation and numerical modeling of carbonation process in reinforced concrete structures Part II. Practical applications

    International Nuclear Information System (INIS)

    Saetta, Anna V.; Vitaliani, Renato V.

    2005-01-01

    The mathematical-numerical method developed by the authors to predict the corrosion initiation time of reinforced concrete structures due to carbonation process, recalled in Part I of this work, is here applied to some real cases. The final aim is to develop and test a practical method for determining the durability characteristics of existing buildings liable to carbonation, as well as estimating the corrosion initiation time of a building at the design stage. Two industrial sheds with different ages and located in different areas have been analyzed performing both experimental tests and numerical analyses. Finally, a case of carbonation-induced failure in a prestressed r.c. beam is presented

  16. Mass and energy balance of the carbonization of babassu nutshell as affected by temperature

    Directory of Open Access Journals (Sweden)

    Thiago de Paula Protásio

    2014-03-01

    Full Text Available The objective of this work was to evaluate the carbonization yield of babassu nutshell as affected by final temperature, as well as the energy losses involved in the process. Three layers constituting the babassu nut, that is, the epicarp, mesocarp and endocarp, were used together. The material was carbonized, considering the following final temperatures: 450, 550, 650, 750, and 850ºC. The following were evaluated: energy and charcoal yields, pyroligneous liquid, non-condensable gases, and fixed carbon. The use of babassu nutshell can be highly feasible for charcoal production. The yield of charcoal from babassu nutshell carbonization was higher than that reported in the literature for Eucalyptus wood carbonization, considering the final temperature of 450ºC. Charcoal and energy yields decreased more sharply at lower temperatures, with a tendency to stabilize at higher temperatures. The energy yields obtained can be considered satisfactory, with losses between 45 and 52% (based on higher heating value and between 43 and 49% (based on lower heating value at temperatures ranging from 450 to 850ºC, respectively. Yields in fixed carbon and pyroligneous liquid are not affected by the final carbonization temperature.

  17. Seasonal and interannual variability of carbon dioxide and water balances of a grassland

    International Nuclear Information System (INIS)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Holtslag, A.A.M.

    2007-01-01

    There is great international concern over the increase of atmospheric carbon dioxide and its effect on vegetation and climate, and vice versa. Many studies on this issue are based on climate model calculations or indirect satellite observations. In contrast we present a 12-year study (1994-2005) on the net ecosystem exchange of carbon dioxide (NEE) and precipitation surplus (i.e., precipitation-evaporation) of a grassland area in the centre of the Netherlands. On basis of direct flux observations and a process-based model we study and quantify the carbon uptake via assimilation and carbon release via soil and plant respiration. It appears that nearly year-round the assimilation term dominates, which indicates an accumulation of carbon dioxide. The mean net carbon uptake for the 12-year period is about 3 tonnes C per hectare, but with a strong seasonal and interannual variability depending on the weather and water budget. This variability may severely hamper the accurate quantification of carbon storage by vegetation in our present climates and its projection for future climates

  18. How Does Recycling of Livestock Manure in Agroecosystems Affect Crop Productivity, Reactive Nitrogen Losses, and Soil Carbon Balance?

    Science.gov (United States)

    Xia, Longlong; Lam, Shu Kee; Yan, Xiaoyuan; Chen, Deli

    2017-07-05

    Recycling of livestock manure in agroecosystems to partially substitute synthetic fertilizer nitrogen (N) input is recommended to alleviate the environmental degradation associated with synthetic N fertilization, which may also affect food security and soil greenhouse gas (GHG) emissions. However, how substituting livestock manure for synthetic N fertilizer affects crop productivity (crop yield; crop N uptake; N use efficiency), reactive N (Nr) losses (ammonia (NH 3 ) emission, N leaching and runoff), GHG (methane, CH 4 ; and nitrous oxide, N 2 O; carbon dioxide) emissions and soil organic carbon (SOC) sequestration in agroecosystems is not well understood. We conducted a global meta-analysis of 141 studies and found that substituting livestock manure for synthetic N fertilizer (with equivalent N rate) significantly increased crop yield by 4.4% and significantly decreased Nr losses via NH 3 emission by 26.8%, N leaching by 28.9% and N runoff by 26.2%. Moreover, annual SOC sequestration was significantly increased by 699.6 and 401.4 kg C ha -1 yr -1 in upland and paddy fields, respectively; CH 4 emission from paddy field was significantly increased by 41.2%, but no significant change of that was observed from upland field; N 2 O emission was not significantly affected by manure substitution in upland or paddy fields. In terms of net soil carbon balance, substituting manure for fertilizer increased carbon sink in upland field, but increased carbon source in paddy field. These results suggest that recycling of livestock manure in agroecosystems improves crop productivity, reduces Nr pollution and increases SOC storage. To attenuate the enhanced carbon source in paddy field, appropriate livestock manure management practices should be adopted.

  19. Reconstruction of annual carbon dynamics and balance for an oligotrophic pine fen

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J; Silvola, J; Aaltonen, H [Joensuu Univ. (Finland). Dept. of Biology; Talanov, A; Ikkonen, E [Karelian Research Centre of Russian Academy of Sciences (Russian Federation). Inst. of Biology; Nykaenen, H; Martikainen, P J [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology

    1997-12-31

    Atmospheric carbon dioxide (CO{sub 2}) is bound by mire vegetation in photosynthesis during the growing season, and is re-released by respiration of plants, soil animals and microorganisms consuming dead organic matter. A small proportion of annual primary production may fall below the water table to anoxic conditions and thus escapes the oxidative decomposition. Also from anoxic peat, carbon is released with clear seasonal and spatial variation as methane (CH{sub 4}.). The rate of carbon accumulation in peat depends on the annual inbalance of plant production and litter decomposition. Exchange of CO{sub 2} and CH{sub 4} between peat, vegetation and the atmosphere thus reflects the dynamics of carbon flows in the ecosystem. Net ecosystem CO{sub 2} exchange (PN), total CO{sub 2} release (RTOT) and CH{sub 4} release (D) from different treeless surfaces of low-sedge Sphagnum papillosum pine fen was studied in eastern Finland. (8 refs.)

  20. Reconstruction of annual carbon dynamics and balance for an oligotrophic pine fen

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.; Silvola, J.; Aaltonen, H. [Joensuu Univ. (Finland). Dept. of Biology; Talanov, A.; Ikkonen, E. [Karelian Research Centre of Russian Academy of Sciences (Russian Federation). Inst. of Biology; Nykaenen, H.; Martikainen, P.J. [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology

    1996-12-31

    Atmospheric carbon dioxide (CO{sub 2}) is bound by mire vegetation in photosynthesis during the growing season, and is re-released by respiration of plants, soil animals and microorganisms consuming dead organic matter. A small proportion of annual primary production may fall below the water table to anoxic conditions and thus escapes the oxidative decomposition. Also from anoxic peat, carbon is released with clear seasonal and spatial variation as methane (CH{sub 4}.). The rate of carbon accumulation in peat depends on the annual inbalance of plant production and litter decomposition. Exchange of CO{sub 2} and CH{sub 4} between peat, vegetation and the atmosphere thus reflects the dynamics of carbon flows in the ecosystem. Net ecosystem CO{sub 2} exchange (PN), total CO{sub 2} release (RTOT) and CH{sub 4} release (D) from different treeless surfaces of low-sedge Sphagnum papillosum pine fen was studied in eastern Finland. (8 refs.)

  1. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m-2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m-2 lower and was negative. Closed

  2. Benthic biogeochemical cycling, nutrient stoichiometry, and carbon and nitrogen mass balances in a eutrophic freshwater bay

    Science.gov (United States)

    Klump, J.V.; Fitzgerald, S.A.; Waplesa, J.T.

    2009-01-01

    Green Bay, while representing only ,7% of the surface area and ??1.4% of the volume of Lake Michigan, contains one-third of the watershed of the lake, and receives approximately one-third of the total nutrient loading to the Lake Michigan basin, largely from the Fox River at the southern end of the bay. With a history of eutrophic conditions dating back nearly a century, the southern portion of the bay behaves as an efficient nutrient and sediment trap, sequestering much of the annual carbon and nitrogen input within sediments accumulating at up to 1 cm per year. Depositional fluxes of organic matter varied from ??0.1 mol C m-2 yr-1 to >10 mol C m-2 yr-1 and were both fairly uniform in stoichiometric composition and relatively labile. Estimates of benthic recycling derived from pore-water concentration gradients, whole-sediment incubation experiments, and deposition-burial models of early diagenesis yielded an estimated 40% of the carbon and 50% of the nitrogen recycled back into the overlying water. Remineralization was relatively rapid with ??50% of the carbon remineralized within <15 yr of deposition, and a mean residence time for metabolizable carbon and nitrogen in the sediments of 20 yr. On average, organic carbon regeneration occurred as 75% CO2, 15% CH4, and 10% dissolved organic carbon (DOC). Carbon and nitrogen budgets for the southern bay were based upon direct measurements of inputs and burial and upon estimates of export and production derived stoichiometrically from a coupled phosphorus budget. Loadings of organic carbon from rivers were ??3.7 mol m-2 yr-1, 80% in the form of DOC and 20% as particulate organic carbon. These inputs were lost through export to northern Green Bay and Lake Michigan (39%), through sediment burial (26%), and net CO2 release to the atmosphere (35%). Total carbon input, including new production, was 4.54 mol m-2 C yr-1, equivalent to ??10% of the gross annual primary production. Nitrogen budget terms were less well quantified

  3. Effects of nutrient loading on the carbon balance of coastal wetland sediments

    Science.gov (United States)

    Morris, J.T.; Bradley, P.M.

    1999-01-01

    Results of a 12-yr study in an oligotrophic South Carolina salt marsh demonstrate that soil respiration increased by 795 g C m-2 yr-1 and that carbon inventories decreased in sediments fertilized with nitrogen and phosphorus. Fertilized plots became net sources of carbon to the atmosphere, and sediment respiration continues in these plots at an accelerated pace. After 12 yr of treatment, soil macroorganic matter in the top 5 cm of sediment was 475 g C m-2 lower in fertilized plots than in controls, which is equivalent to a constant loss rate of 40 g C m-2 yr-1. It is not known whether soil carbon in fertilized plots has reached a new equilibrium or continues to decline. The increase in soil respiration in the fertilized plots was far greater than the loss of sediment organic matter, which indicates that the increase in soil respiration was largely due to an increase in primary production. Sediment respiration in laboratory incubations also demonstrated positive effects of nutrients. Thus, the results indicate that increased nutrient loading of oligotrophic wetlands can lead to an increased rate of sediment carbon turnover and a net loss of carbon from sediments.

  4. Carbon stocks, greenhouse gas emissions and water balance of Sudanese savannah woodlands in relation to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Alam, S. A.

    2013-06-01

    Understanding the carbon (C) sequestration potential of drylands requires knowledge of the stocks of C in soils and biomass and on the factors affecting them. The overall aim of the study was to determine and evaluate the variation in the C stocks and water balance of Acacia savannah woodlands across the dryland (arid and semi-arid) region (10-16 deg N; 21-36 deg E) of the former Sudan (now mainly in the Republic of the Sudan) and how they are related to climatic factors and may be affected by climate change. The role played by small but numerous brick making industries on woodland deforestation in the region and greenhouse gas production was also investigated. The study region is often referred to as the gum belt because it is the world's major source of gum Arabic, which is harvested from Acacia trees. The soils in the centre and west of the region are mainly Arenosols (sandy soils) and those in the eastern part are mainly Vertisols (clay soils). The soils are C poor and often in a degraded state. This dissertation consists of a summary section and four articles (Study I, II, III and IV). Study I focuses on fuelwood consumption by the brick making industries (BMIs) and associated deforestation and greenhouse gas (GHG) emissions. In Study II the C densities (g C m-2) of the woodland tree biomass and soil (1 m) for 39 map sheets covering the study region were determined from national forest inventory data and global soil databases and the dependence on mean annual precipitation (MAP) and mean annual temperature (MAT) determined. The water balance of savannah woodlands for the same 39 map sheets was modelled in Study III and the variation in water balance components across the region evaluated. The potential impacts of climate change on woodland biomass C density and water-use (actual evapotranspiration, AET) was analysed for eight of the map sheets in Study IV. Sudanese BMIs consume a considerable amount of fuelwood that mainly comes from unsustainably managed

  5. Present and Future Carbon Balance of Russia's Northern Ecosystems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chapin, F. Stuart III; Zimov, Sergei A.

    2000-08-28

    Recent increases in the seasonal amplitude of atmospheric CO{sub 2} at high latitudes suggest a widespread biospheric response to high-latitude warming. We have shown that the seasonal amplitude of net ecosystem carbon exchange by northern Siberian ecosystems is greater in disturbed than undisturbed sites, due to increased summer influx and increased winter efflux. Net carbon gain in summer and respiration in winter were greater in a cool than in a warm year, especially in disturbed sites and did not differ between high-arctic and treeline sites, suggesting that high-latitude warming, if it occurred, would have little effect or would reduce seasonal amplitude of carbon exchange. We suggest that increased disturbance contributes significantly to the amplified seasonal cycle of atmospheric CO{sub 2} at high latitudes.

  6. Effect of part replacement of silica sand with carbon black on composite properties

    International Nuclear Information System (INIS)

    Adeosun, B.F.; Olaofe, O.

    2003-01-01

    We have reported the properties of natural rubber filled with locally available materials (Adu et al 2000). The effect of local clay, limestone, silica sand and charcoal on the properties of natural rubber has been examined. Results have shown detrimental effects of silica sand on the properties of natural rubber compound. It has been reported that when silica is used as a part for part replacement of carbon black, the heat build up the composite decreased whilst tear resistance improved. Results revealed that within the filler content range used in the present work, the hardness, modulus, and tensile strength of composites loaded with silica sand/carbon black showed enhanced magnitude over the composite loaded singly with silica sand. These parameters generally increased with increasing carbon black content in the composite. New area of use requiring moderate level of tensile strength, hardness and modulus (as in soles of shoes and engine mounts) is therefore opened up for silica sand.(author)

  7. Instrumentation and analytical methods in carbon balance studies - inorganic components in a marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Skjelvan, I.; Johannessen, T.; Miller, L.; Stoll, M.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Substantial amounts of anthropogenic CO{sub 2} enters the atmosphere. The land biota acts as a sink for CO{sub 2}, with uncertain consequences. About 30% of the anthropogenic CO{sub 2} added to the atmosphere is absorbed by the ocean and how the ocean acts as a sink is central in understanding the carbon cycle. In their project the authors investigate the inorganic carbon in the ocean, especially total dissolved inorganic carbon, alkalinity, and partial pressure of CO{sub 2} (pCO{sub 2}) in surface ocean and atmosphere. To determine total dissolved inorganic carbon, coulometric analysis is used in which an exact amount of sea water is acidified and the amount of carbon extracted is determined by a coulometer. Alkalinity is determined by potentiometric titration. In the pCO{sub 2} measurement, a small amount of air is circulated in a large amount of sea water and when after some time the amount of CO{sub 2} in the air reflects the CO{sub 2} concentration in the water, the pCO{sub 2} in the gas phase is determined by infra-red detection. The atmospheric pCO{sub 2} is also determined, and the difference between the two partial pressures gives information about source or sink activities. Total carbon and alkalinity measurements are done on discrete samples taken from all depths in the ocean, but for partial pressure detection an underway system is used, which determines the pCO{sub 2} in the surface ocean continuously

  8. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    Science.gov (United States)

    Jiang, F.; Wang, H. M.; Chen, J. M.; Machida, T.; Zhou, L. X.; Ju, W. M.; Matsueda, H.; Sawa, Y.

    2014-09-01

    Terrestrial carbon dioxide (CO2) flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002-2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the Boreal Ecosystems Productivity Simulator (BEPS) model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced (2-12%). CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements may have improved the inversion results.

  9. The development of RFT technique for carbon steel tubes in balance-of-plant heat exchangers

    International Nuclear Information System (INIS)

    Kim, Chang Soo; Kim, Han Jong; Moon, Yong Sick; Kim, Jae Dong; Kim, Wang Bae; Nam, Min Woo

    2005-01-01

    The NDT method of carbon steel tubes is applied RFT technique. As other NDT methods, It is surprising that RFT has been rapidly developed over the past decade. These improvements have resulted in multi-frequency system, dual driver probes and development of analysis technique. Also these improvements give some profit to power plants as well as general industry. Therefore, the purpose of this study is to improve the reliability of RFT technique for carbon steel tubes. To uplift RFT technique, probes, calibration standards and specimen was developed.

  10. Vulnerability of permafrost carbon to global warming. Part II: sensitivity of permafrost carbon stock to global warming

    Energy Technology Data Exchange (ETDEWEB)

    Khvorostyanov, D.V.; Ciais, G. (Laboratoire des Sciences du Climat et l' Environnement, Saclay (France)); Krinner, G. (Laboratoire de Glaciologie et Geophysique de l' Environnement, St Martin d' Heres (France)). e-mail: Dimitry.Khvorostiyanov@lsce.ipsl.fr; Zimov, S.A. (Northeast Science Station, Cherskii (RU)); Corradi, C. (UNITUS, Univ. of Tuscia, Veterbo (Italy)); Guggenberger, G. (Inst. of Soil Science and Plant Nutrition, Martin-Luther-Univ., Halle-Wittenberg (DE))

    2008-07-01

    In the companion paper (Part I), we presented a model of permafrost carbon cycle to study the sensitivity of frozen carbon stocks to future climate warming. The mobilization of deep carbon stock of the frozen Pleistocene soil in the case of rapid stepwise increase of atmospheric temperature was considered. In this work, we adapted the model to be used also for floodplain tundra sites and to account for the processes in the soil active layer. The new processes taken into account are litter input and decomposition, plant-mediated transport of methane, and leaching of exudates from plant roots. The SRES-A2 transient climate warming scenario of the IPSL CM4 climate model is used to study the carbon fluxes from the carbon-rich Pleistocene soil with seasonal active-layer carbon cycling on top of it. For a point to the southwest from the western branch of Yedoma Ice Complex, where the climate warming is strong enough to trigger self-sustainable decomposition processes, about 256 kg C/m2, or 70% of the initial soil carbon stock under present-day climate conditions, are emitted to the atmosphere in about 120 yr, including 20 kg C/m2 released as methane. The total average flux of CO{sub 2} and methane emissions to the atmosphere during this time is of 2.1 kg C/m2/yr. Within the Yedoma, whose most part of the territory remains relatively cold, the emissions are much smaller: 0.2 kg C/m2/yr between 2050 and 2100 for Yakutsk area. In a test case with saturated upper-soil meter, when the runoff is insufficient to evacuate the meltwater, 0.05 kg CH{sub 4}/m2/yr on average are emitted as methane during 250 yr starting from 2050. The latter can translate to the upper bound of 1 GtC/yr in CO{sub 2} equivalent from the 1 million km2 area of the Yedoma

  11. Engineered in situ bioremediation of a petroleum hydrocarbon-contaminated aquifer: assessment of mineralization based on alkalinity, inorganic carbon and stable carbon isotope balances

    Science.gov (United States)

    Hunkeler, Daniel; Höhener, Patrick; Bernasconi, Stefano; Zeyer, Josef

    1999-04-01

    A concept is proposed to assess in situ petroleum hydrocarbon mineralization by combining data on oxidant consumption, production of reduced species, CH 4, alkalinity and dissolved inorganic carbon (DIC) with measurements of stable isotope ratios. The concept was applied to a diesel fuel contaminated aquifer in Menziken, Switzerland, which was treated by engineered in situ bioremediation. In the contaminated aquifer, added oxidants (O 2 and NO 3-) were consumed, elevated concentrations of Fe(II), Mn(II), CH 4, alkalinity and DIC were detected and the DIC was generally depleted in 13C compared to the background. The DIC production was larger than expected based on the consumption of dissolved oxidants and the production of reduced species. Stable carbon isotope balances revealed that the DIC production in the aquifer originated mainly from microbial petroleum hydrocarbon mineralization, and that geochemical reactions such as carbonate dissolution produced little DIC. This suggests that petroleum hydrocarbon mineralization can be underestimated if it is determined based on concentrations of dissolved oxidants and reduced species.

  12. Size and frequency of natural forest disturbances and the Amazon forest carbon balance

    Science.gov (United States)

    F.D.B. Espirito-Santo; M. Gloor; M. Keller; Y. Malhi; S. Saatchi; B. Nelson; R.C. Oliveira Junior; C. Pereira; J. Lloyd; S. Frolking; M. Palace; Y.E. Shimabukuro; V. Duarte; A. Monteagudo Mendoza; G. Lopez-Gonzalez; T.R. Baker; T.R. Feldpausch; R.J.W. Brienen; G.P. Asner; D.S. Boyd; O.L. Phillips

    2014-01-01

    Forest inventory studies in the Amazon indicate a large terrestrial carbon sink. However, field plots may fail to represent forest mortality processes at landscape-scales of tropical forests. Here we characterize the frequency distribution of disturbance events in natural forests from 0.01 ha to 2,651 ha size throughout Amazonia using a novel...

  13. Interactions of changing climate and shifts in forest composition on stand carbon balance

    Science.gov (United States)

    Chiang Jyh-Min; Louis Iverson; Anantha Prasad; Kim Brown

    2006-01-01

    Given that climate influences forest biogeographic distribution, many researchers have created models predicting shifts in tree species range with future climate change scenarios. The objective of this study is to investigate the forest carbon consequences of shifts in stand species composition with current and future climate scenarios using such a model.

  14. Detecting the critical periods that underpin interannual fluctuations in the carbon balance of European forests

    DEFF Research Database (Denmark)

    le Maire, Guerric; Delpierre, Nicolas; Jung, Martin

    2010-01-01

    . The analysis was first conducted at seven European forest flux tower sites with contrasting species and climatic conditions. Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE), a generic process-based model, represented fairly well most features of the critical period patterns and their climate...

  15. Modeling effects of hydrological changes on the carbon and nitrogen balance of oak in floodplains.

    Science.gov (United States)

    Pietsch, Stephan A; Hasenauer, Hubert; Kucera, Jiŕi; Cermák, Jan

    2003-08-01

    We extended the applicability of the ecosystem model BIOME-BGC to floodplain ecosystems to study effects of hydrological changes on Quercus robur L. stands. The extended model assesses floodplain peculiarities, i.e., seasonal flooding and water infiltration from the groundwater table. Our interest was the tradeoff between (a). maintaining regional applicability with respect to available model input information, (b). incorporating the necessary mechanistic detail and (c). keeping the computational effort at an acceptable level. An evaluation based on observed transpiration, timber volume, soil carbon and soil nitrogen content showed that the extended model produced unbiased results. We also investigated the impact of hydrological changes on our oak stands as a result of the completion of an artificial canal network in 1971, which has stopped regular springtime flooding. A comparison of the 11 years before versus the 11 years after 1971 demonstrated that the hydrological changes affected mainly the annual variation across years in leaf area index (LAI) and soil carbon and nitrogen sequestration, leading to stagnation of carbon and nitrogen stocks, but to an increase in the variance across years. However, carbon sequestration to timber was unaffected and exhibited no significant change in cross-year variation. Finally, we investigated how drawdown of the water table, a general problem in the region, affects modeled ecosystem behavior. We found a further amplification of cross-year LAI fluctuations, but the variance in soil carbon and nitrogen stocks decreased. Volume increment was unaffected, suggesting a stabilization of the ecosystem two decades after implementation of water management measures.

  16. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance

    Directory of Open Access Journals (Sweden)

    Thijs Leendert Pons

    2014-02-01

    Full Text Available Plant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A partitioned in C available for growth and C required for respiration (R, is thus irradiance dependent. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 µmol m-2 s-1 (1.2 mol m-2 day-1 to 500 µmol m-2 s-1 (30 mol m-2 day-1. Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies towards a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated with a superior C-balance

  17. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance.

    Science.gov (United States)

    Pons, Thijs L; Poorter, Hendrik

    2014-01-01

    The carbon balance is defined here as the partitioning of daily whole-plant gross CO2 assimilation (A) in C available for growth and C required for respiration (R). A scales positively with growth irradiance and there is evidence for an irradiance dependence of R as well. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 μmol m(-2) s(-1) (1.2 mol m(-2) day(-1)) to 500 μmol m(-2) s(-1) (30 mol m(-2) day(-1)). Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area) at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light-saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies toward a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated

  18. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

  19. Energy and carbon balances in cheatgrass, an essay in autecology. [Shortwave radiation, radiowave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.

    1975-01-01

    An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)

  20. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.

    1997-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  1. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J

    1998-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  2. Modelling and computing the peaks of carbon emission with balanced growth

    International Nuclear Information System (INIS)

    Chang, Shuhua; Wang, Xinyu; Wang, Zheng

    2016-01-01

    Highlights: • We use a more practical utility function to quantify the society’s welfare. • A so-called discontinuous Galerkin method is proposed to solve the ordinary differential equation satisfied by the consumption. • The theoretical results of the discontinuous Galerkin method are obtained. • We establish a Markov model to forecast the energy mix and the industrial structure. - Abstract: In this paper, we assume that under the balanced and optimal economic growth path, the economic growth rate is equal to the consumption growth rate, from which we can obtain the ordinary differential equation governing the consumption level by solving an optimal control problem. Then, a novel numerical method, namely a so-called discontinuous Galerkin method, is applied to solve the ordinary differential equation. The error estimation and the superconvergence estimation of this method are also performed. The model’s mechanism, which makes our assumption coherent, is that once the energy intensity is given, the economic growth is determined, followed by the GDP, the energy demand and the emissions. By applying this model to China, we obtain the conclusion that under the balanced and optimal economic growth path the CO_2 emission will reach its peak in 2030 in China, which is consistent with the U.S.-China Joint Announcement on Climate Change and with other previous scientific results.

  3. Balancing Act

    Science.gov (United States)

    Part of being an Active, More Powerful You means finding balance in your daily life: taking on the Must-dos and finding time for some Should Dos and Want-to-Dos. Sometimes, emotions and commitments can come into play and upset the balance.

  4. The importance of age-related decline in forest NPP for modeling regional carbon balances.

    Science.gov (United States)

    Zaehle, Sönke; Sitch, Stephen; Prentice, I Colin; Liski, Jari; Cramer, Wolfgang; Erhard, Markus; Hickler, Thomas; Smith, Benjamin

    2006-08-01

    We show the implications of the commonly observed age-related decline in aboveground productivity of forests, and hence forest age structure, on the carbon dynamics of European forests in response to historical changes in environmental conditions. Size-dependent carbon allocation in trees to counteract increasing hydraulic resistance with tree height has been hypothesized to be responsible for this decline. Incorporated into a global terrestrial biosphere model (the Lund-Potsdam-Jena model, LPJ), this hypothesis improves the simulated increase in biomass with stand age. Application of the advanced model, including a generic representation of forest management in even-aged stands, for 77 European provinces shows that model-based estimates of biomass development with age compare favorably with inventory-based estimates for different tree species. Model estimates of biomass densities on province and country levels, and trends in growth increment along an annual mean temperature gradient are in broad agreement with inventory data. However, the level of agreement between modeled and inventory-based estimates varies markedly between countries and provinces. The model is able to reproduce the present-day age structure of forests and the ratio of biomass removals to increment on a European scale based on observed changes in climate, atmospheric CO2 concentration, forest area, and wood demand between 1948 and 2000. Vegetation in European forests is modeled to sequester carbon at a rate of 100 Tg C/yr, which corresponds well to forest inventory-based estimates.

  5. Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change

    Directory of Open Access Journals (Sweden)

    Chunyi Ji

    2016-11-01

    Full Text Available The carbon sequestration of harvested wood products (HWP plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013 (IPCC, this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China’s HWP carbon pool increased from 130 Teragrams Carbon (TgC in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China.

  6. Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change.

    Science.gov (United States)

    Ji, Chunyi; Cao, Wenbin; Chen, Yong; Yang, Hongqiang

    2016-11-12

    The carbon sequestration of harvested wood products (HWP) plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013) (IPCC), this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China's HWP carbon pool increased from 130 Teragrams Carbon (TgC) in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China.

  7. Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change

    Science.gov (United States)

    Ji, Chunyi; Cao, Wenbin; Chen, Yong; Yang, Hongqiang

    2016-01-01

    The carbon sequestration of harvested wood products (HWP) plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013) (IPCC), this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China’s HWP carbon pool increased from 130 Teragrams Carbon (TgC) in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China. PMID:27845760

  8. Carbon dioxide degassing at the groundwater-stream-atmosphere interface: isotopic equilibration and hydrological mass balance in a sandy watershed

    Science.gov (United States)

    Deirmendjian, Loris; Abril, Gwenaël

    2018-03-01

    Streams and rivers emit significant amounts of CO2 and constitute a preferential pathway of carbon transport from terrestrial ecosystems to the atmosphere. However, the estimation of CO2 degassing based on the water-air CO2 gradient, gas transfer velocity and stream surface area is subject to large uncertainties. Furthermore, the stable isotope signature of dissolved inorganic carbon (δ13C-DIC) in streams is strongly impacted by gas exchange, which makes it a useful tracer of CO2 degassing under specific conditions. For this study, we characterized the annual transfers of dissolved inorganic carbon (DIC) along the groundwater-stream-river continuum based on DIC concentrations, stable isotope composition and measurements of stream discharges. We selected a homogeneous, forested and sandy lowland watershed as a study site, where the hydrology occurs almost exclusively through drainage of shallow groundwater (no surface runoff). We observed the first general spatial pattern of decreases in pCO2 and DIC and an increase in δ13C-DIC from groundwater to stream orders 1 and 2, which was due to the experimentally verified faster degassing of groundwater 12C-DIC compared to 13C-DIC. This downstream enrichment in 13C-DIC could be modelled by simply considering the isotopic equilibration of groundwater-derived DIC with the atmosphere during CO2 degassing. A second spatial pattern occurred between stream orders 2 and 4, consisting of an increase in the proportion of carbonate alkalinity to the DIC accompanied by the enrichment of 13C in the stream DIC, which was due to the occurrence of carbonate rock weathering downstream. We could separate the contribution of these two processes (gas exchange and carbonate weathering) in the stable isotope budget of the river network. Thereafter, we built a hydrological mass balance based on drainages and the relative contribution of groundwater in streams of increasing order. After combining with the dissolved CO2 concentrations, we

  9. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Robert S [UNR; Smith, Stanley D [UNLV; Evans, Dave [WSU; Ogle, Kiona [ASU; Fenstermaker, Lynn [DRI

    2012-12-13

    Our results from the 10-year elevated atmospheric CO{sub 2} concentration study at the Nevada Desert FACE (Free-air CO{sub 2} Enrichment) Facility (NDFF) indicate that the Mojave Desert is a dynamic ecosystem with the capacity to respond quickly to environmental changes. The Mojave Desert ecosystem is accumulating carbon (C), and over the 10-year experiment, C accumulation was significantly greater under elevated [CO{sub 2}] than under ambient, despite great fluctuations in C inputs from year to year and even apparent reversals in which [CO{sub 2}] treatment had greater C accumulations.

  10. The carbon balance and greenhouse effects of the Finnish forest sector at present, in the past and future

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K. [Technical Research Centre of Finland, Espoo (Finland)

    1996-12-31

    In this study the greenhouse impact of the total Finnish forest sector was considered, which means that the estimated emissions and sink effects from exported forest products were also included. The forest biomass is and seems to be in the next decades the most important factor in the carbon balance of the total forest sector. The development alternatives of forest industries and waste management practices has still a remarkable influence on the greenhouse impact of the Finnish forest sector. The waste management practices in the future has an important influence on the emissions but the exact net greenhouse impact of the landfills is still uncertain. However, the methane emissions from existing landfills can be reduced essentially by gas recovery. Increased incineration and energy recovery of wood waste (and replacing fossil fuel use by it) is also a future alternative for reducing the greenhouse effects in the forest sector. The sequestration of carbon by increasing the storages of long-lived wood products in use meets difficulties in practice because of all the material losses in wood using chain and the natural removal of old wood products. An important advantage of mechanical wood processing and the succeeding refinement chain is still their relative low use of energy

  11. The carbon balance of European croplands: a Trans-European, cross-site, multi model simulation study

    Science.gov (United States)

    Wattenbach, Martin; Sus, Oliver; Vuichard, Nicolas; Lehuger, Simon; Leip, Adrian; Gottschalk, Pia; Smith, Pete

    2010-05-01

    Croplands cover approximately 45% of Europe and play a significant role in the overall carbon budget of the continent. However, the estimation of the regional carbon balance is still uncertain. Here, we present a multi-site model comparison for four cropland ecosystem models namely the DNDC, ORCHIDEE-STICS, CERES-EGC and SPA model. We compare the accuracy of the models in predicting net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (Reco) as well as actual evapo-transpiration (ETa) for winter wheat (Triticum aestivum L.), winter barley (Hordeum vulgare L.) and maize (Zea mays L.) derived from eddy covariance measurements on five sites of the CarboEurope IP network. The models are all able to simulate mean daily GPP. The simulation results for mean daily ETa and Reco are, however, less accurate. The resulting simulation of daily NEE is adequate beside some cases where models fail due to a lack in phase and amplitude alignment. ORCHIDEE-STICS and the SPA demonstrate the best performance, nevertheless, they are not able to simulate full crop rotations under consideration of multiple management. CERES-EGC and especially DNDC although exhibiting a lower level of model accuracy are able to simulate such conditions resulting in more accurate annual cumulative NEE.

  12. The carbon balance and greenhouse effects of the Finnish forest sector at present, in the past and future

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K [Technical Research Centre of Finland, Espoo (Finland)

    1997-12-31

    In this study the greenhouse impact of the total Finnish forest sector was considered, which means that the estimated emissions and sink effects from exported forest products were also included. The forest biomass is and seems to be in the next decades the most important factor in the carbon balance of the total forest sector. The development alternatives of forest industries and waste management practices has still a remarkable influence on the greenhouse impact of the Finnish forest sector. The waste management practices in the future has an important influence on the emissions but the exact net greenhouse impact of the landfills is still uncertain. However, the methane emissions from existing landfills can be reduced essentially by gas recovery. Increased incineration and energy recovery of wood waste (and replacing fossil fuel use by it) is also a future alternative for reducing the greenhouse effects in the forest sector. The sequestration of carbon by increasing the storages of long-lived wood products in use meets difficulties in practice because of all the material losses in wood using chain and the natural removal of old wood products. An important advantage of mechanical wood processing and the succeeding refinement chain is still their relative low use of energy

  13. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    Science.gov (United States)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  14. Managing Motherhood in the Australian Construction Industry: Work-family Balance, Parental Leave and Part-time Work

    Directory of Open Access Journals (Sweden)

    Helen Lingard

    2012-11-01

    Full Text Available A survey of women in the Australian construction industrywas undertaken to examine women's work experiencesin construction. Questionnaires were distributed to threehundred women in construction occupations and 109completed and usable questionnaires were returned.Women were found to be seriously under-represented insite-based roles. Site/project engineers worked longer hoursthan other occupational groups and expressed significantlygreater work-family conflict. Lack of flexibility and theinability to balance work and family were common themesin the qualitative comments made by many respondents.Even when women indicated that part time work options andmaternity entitlements were provided by their organizations,many expressed a reluctance to use them and perceivedcareer penalty associated with this usage. It is concludedthat more flexible work schedules and the implementationof family-friendly policies may encourage more women intosite-based roles in construction. The paper concludes thatthe rigid work practices presently in place act as a subtleform of discrimination. The provision of such policies willonly be effective if cultural and attitudinal change is alsoachieved.

  15. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2016-07-01

    Full Text Available Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve, while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve. This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.

  16. Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey

    Science.gov (United States)

    Correia, A. C.; Costa-e-Silva, F.; Dubbert, M.; Piayda, A.; Pereira, J. S.

    2016-10-01

    Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can

  17. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    Science.gov (United States)

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. CO2 enrichment and carbon partitioning to phenolics: do plant responses accord better with the protein competition or the growth-differentiation balance models?

    Science.gov (United States)

    W.J. Mattson; R. Julkunen-Tiitto; D.A. Herms

    2005-01-01

    Rising levels of atmospheric CO2 can alter plant growth and partitioning to secondary metabolites. The protein competition model (PCM) and the extended growth/differentiation balance model (GDBe) are similar but alternative models that address ontogenetic and environmental effects on whole-plant carbon partitioning to the...

  19. Initial water deficit effects on Lupinus albus photosynthetic performance, carbon metabolism, and hormonal balance: metabolic reorganization prior to early stress responses

    Czech Academy of Sciences Publication Activity Database

    Pinheiro, C.; António, C.; Dobrev, Petre; Vaňková, Radomíra; Wilson, J. C.

    2011-01-01

    Roč. 62, č. 14 (2011), s. 4965-4974 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : Carbon metabolism * hormone balance * LC-MS Subject RIV: EF - Botanics Impact factor: 5.364, year: 2011

  20. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    NARCIS (Netherlands)

    Filgueira, R.; Byron, C.J.; Comeau, L.A.; Jansen, H.M.; Smaal, A.C.

    2015-01-01

    The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities,

  1. Balanced and Unbalanced Circulations in a Primitive Equation Simulation of a Midlatitude MCC. Part I: The Numerical Simulation.

    Science.gov (United States)

    Olsson, Peter Q.; Cotton, William R.

    1997-02-01

    banded vorticity structure at midtropospheric levels. These bands were found to be due to the apparent vertical transport of zonal momentum by the descending rear-to-front circulation, or rear-inflow jet. An equivalent alternative viewpoint of this process, deformation of horizontal vorticity filaments by the convective updrafts and rear-inflow jet, is discussed.Part II of this work presents a complementary approach to the analysis presented here, demonstrating that the circulations seen in this MCC simulation are, to a large degree, contained within the nonlinear balance approximation, the related balanced omega equation, and the PV as analyzed from the PE model results.

  2. Terrestrial Carbon [Environmental Pollution: Part I, Special Issue, March 2002; Part II, Special Issue Supplement to 116/3, 2002

    Energy Technology Data Exchange (ETDEWEB)

    Mickler, Robert (ed.); McNulty, Steven (ed.)

    2002-03-01

    These issues contain a total of forty-four peer reviewed science papers on terrestrial carbon presented at the Advances in Terrestrial Ecosystem Carbon Inventory, Measurements, and Monitoring Conference held in Raleigh, N.C., in October 2000.

  3. Enabling intelligent copernicus services for carbon and water balance modeling of boreal forest ecosystems - North State

    Science.gov (United States)

    Häme, Tuomas; Mutanen, Teemu; Rauste, Yrjö; Antropov, Oleg; Molinier, Matthieu; Quegan, Shaun; Kantzas, Euripides; Mäkelä, Annikki; Minunno, Francesco; Atli Benediktsson, Jon; Falco, Nicola; Arnason, Kolbeinn; Storvold, Rune; Haarpaintner, Jörg; Elsakov, Vladimir; Rasinmäki, Jussi

    2015-04-01

    The objective of project North State, funded by Framework Program 7 of the European Union, is to develop innovative data fusion methods that exploit the new generation of multi-source data from Sentinels and other satellites in an intelligent, self-learning framework. The remote sensing outputs are interfaced with state-of-the-art carbon and water flux models for monitoring the fluxes over boreal Europe to reduce current large uncertainties. This will provide a paradigm for the development of products for future Copernicus services. The models to be interfaced are a dynamic vegetation model and a light use efficiency model. We have identified four groups of variables that will be estimated with remote sensed data: land cover variables, forest characteristics, vegetation activity, and hydrological variables. The estimates will be used as model inputs and to validate the model outputs. The earth observation variables are computed as automatically as possible, with an objective to completely automatic estimation. North State has two sites for intensive studies in southern and northern Finland, respectively, one in Iceland and one in state Komi of Russia. Additionally, the model input variables will be estimated and models applied over European boreal and sub-arctic region from Ural Mountains to Iceland. The accuracy assessment of the earth observation variables will follow statistical sampling design. Model output predictions are compared to earth observation variables. Also flux tower measurements are applied in the model assessment. In the paper, results of hyperspectral, Sentinel-1, and Landsat data and their use in the models is presented. Also an example of a completely automatic land cover class prediction is reported.

  4. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

    Science.gov (United States)

    Wood, Tana E.; Cavaleri, Molly A.; Reed, Sasha C.

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  5. Mechanical performance of carbon-epoxy laminates. Part II: quasi-static and fatigue tensile properties

    Directory of Open Access Journals (Sweden)

    José Ricardo Tarpani

    2006-06-01

    Full Text Available In Part II of this work, quasi-static tensile properties of four aeronautical grade carbon-epoxy composite laminates, in both the as-received and pre-fatigued states, have been determined and compared. Quasi-static mechanical properties assessed were tensile strength and stiffness, tenacity (toughness at the maximum load and for a 50% load drop-off. In general, as-molded unidirectional cross-ply carbon fiber (tape reinforcements impregnated with either standard or rubber-toughened epoxy resin exhibited the maximum performance. The materials also displayed a significant tenacification (toughening after exposed to cyclic loading, resulting from the increased stress (the so-called wear-in phenomenon and/or strain at the maximum load capacity of the specimens. With no exceptions, two-dimensional woven textile (fabric pre-forms fractured catastrophically under identical cyclic loading conditions imposed to the fiber tape architecture, thus preventing their residual properties from being determined.

  6. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  7. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-03-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  8. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda; Sousa, Maria João; Leão, Cecília

    2016-04-26

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging.

  9. A Model for Interpreting High-Tower CO2 Concentration Records for the Surface Carbon Balance Information

    Science.gov (United States)

    Chen, B.; Chen, J. M.; Higuchi, K.; Chan, D.; Shashkov, A.

    2002-05-01

    Atmospheric CO2 concentration measurements have been made by scientists of Meteorological Service of Canada on a 40 m tower for the last 10 years at 15 minute intervals over a mostly intact boreal forest near Fraserdale (50N, 81W), Ontario, Canada. The long time records of CO2 as well as basic meteorological variables provide a unique opportunity to investigate any potential changes in the ecosystem in terms of carbon balance. A model is needed to decipher the carbon cycle signals from the diurnal and seasonal variation patterns in the CO2 record. For this purpose, the Boreal Ecosystem Productivity Simulator (BEPS) is expanded to include a one-dimensional CO2 vertical transfer model involving the interaction between plant canopies and the atmosphere in the surface layer and the diurnal dynamics of the mixed layer. An analytical solution of the scalar transfer equation within the surface layer is found using an assumption that the diurnal oscillation of CO2 concentration at a given height is sinusoidal, which is suitable for the investigation of the changes in diurnal variation pattern over the 10 year period. The complex interactions between the daily cycle of the atmosphere and vegetation CO2 exchange and the daily evolution of mixed layer entrainment of CO2 determines the CO2 variation pattern at a given height. The expanded BEPS can simulate within ñ2 ppm the hourly CO2 records at the 40 m measurement height. The annual totals of gross primary productivity (GPP), net primary productivity (NPP) and net ecosystem productivity (NEP), summed up from the hourly results, agree within 5% of previous estimates of BEPS at daily steps, indicating the internal consistency of the hourly model. The model is therefore ready for exploring changes in the CO2 record as affected by changes in the forest ecosystems upwind of the tower. Preliminary results indicate that the diurnal variation amplitude of CO2 has increased by 10-20% over the 10 years period, and this change can

  10. A Comprehensive Energy Analysis and Related Carbon Footprint of Dairy Farms, Part 1: Direct Energy Requirements

    Directory of Open Access Journals (Sweden)

    Giuseppe Todde

    2018-02-01

    Full Text Available Dairy cattle farms are continuously developing more intensive systems of management which require higher utilization of durable and not-durable inputs. These inputs are responsible of significant direct and indirect fossil energy requirements which are related to remarkable emissions of CO2. This study aims to analyze direct energy requirements and the related carbon footprint of a large population of conventional dairy farms located in the south of Italy. A detailed survey of electricity, diesel and Liquefied Petroleum Gas (LPG consumptions has been carried out among on-farm activities. The results of the analyses showed an annual average fuel consumption of 40 kg per tonne of milk, while electricity accounted for 73 kWh per tonne of milk produced. Expressing the direct energy inputs as primary energy, diesel fuel results the main resource used in on-farm activities, accounting for 72% of the total fossil primary energy requirement, while electricity represents only 27%. Moreover, larger farms were able to use more efficiently the direct energy inputs and reduce the related emissions of carbon dioxide per unit of milk produced, since the milk yield increases with the herd size. The global average farm emissions of carbon dioxide equivalent, due to all direct energy usages, accounted for 156 kg CO2-eq per tonne of Fat and Protein Corrected Milk (FPCM, while farms that raise more than 200 heads emitted 36% less than the average value. In this two-part series, the total energy demand (Part 1 + Part 2 per farm is mainly due to agricultural inputs and fuel consumption, which have the largest quota of the annual requirements for each milk yield class. These results also showed that large size farms held lower CO2-eq emissions when referred to the mass of milk produced.

  11. Space–time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea

    Directory of Open Access Journals (Sweden)

    I. P. Semiletov

    2013-09-01

    Full Text Available This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB and adjacent part of the Laptev Sea by studying the inter-annual, seasonal, and meso-scale variability of carbon and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO2 emission. Here we present data sets obtained on summer cruises and winter expeditions during 12 yr of investigation. Based on data analysis, we suggest that in the heterotrophic BKB area, input of terrestrially borne organic carbon (OC varies seasonally and inter-annually and is largely determined by rates of coastal erosion and river discharge. Two different BKB sedimentation regimes were revealed: Type 1 (erosion accumulation and Type 2 (accumulation. A Type 1 sedimentation regime occurs more often and is believed to be the quantitatively most important mechanism for suspended particular matter (SPM and particulate organic carbon (POC delivery to the BKB. The mean SPM concentration observed in the BKB under a Type 1 regime was one order of magnitude greater than the mean concentration of SPM (~ 20 mg L−1 observed along the Lena River stream in summer 2003. Loadings of the BKB water column with particulate material vary by more than a factor of two between the two regimes. Higher partial pressure of CO2 (pCO2, higher concentrations of nutrients, and lower levels of oxygen saturation were observed in the bottom water near the eroded coasts, implying that coastal erosion and subsequent oxidation of eroded organic matter (OM rather than the Lena River serves as the predominant source of nutrients to the BKB. Atmospheric CO2 fluxes from the sea surface in the BKB vary from 1 to 95 mmol m−2 day−1 and are determined by specific features of hydrology and wind conditions, which change spatially, seasonally, and inter-annually. Mean values of CO2 emission from the shallow Laptev Sea were similar in September 1999 and 2005 (7.2 and 7

  12. Space-time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea

    Science.gov (United States)

    Semiletov, I. P.; Shakhova, N. E.; Pipko, I. I.; Pugach, S. P.; Charkin, A. N.; Dudarev, O. V.; Kosmach, D. A.; Nishino, S.

    2013-09-01

    This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB) and adjacent part of the Laptev Sea by studying the inter-annual, seasonal, and meso-scale variability of carbon and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO2) emission. Here we present data sets obtained on summer cruises and winter expeditions during 12 yr of investigation. Based on data analysis, we suggest that in the heterotrophic BKB area, input of terrestrially borne organic carbon (OC) varies seasonally and inter-annually and is largely determined by rates of coastal erosion and river discharge. Two different BKB sedimentation regimes were revealed: Type 1 (erosion accumulation) and Type 2 (accumulation). A Type 1 sedimentation regime occurs more often and is believed to be the quantitatively most important mechanism for suspended particular matter (SPM) and particulate organic carbon (POC) delivery to the BKB. The mean SPM concentration observed in the BKB under a Type 1 regime was one order of magnitude greater than the mean concentration of SPM (~ 20 mg L-1) observed along the Lena River stream in summer 2003. Loadings of the BKB water column with particulate material vary by more than a factor of two between the two regimes. Higher partial pressure of CO2 (pCO2), higher concentrations of nutrients, and lower levels of oxygen saturation were observed in the bottom water near the eroded coasts, implying that coastal erosion and subsequent oxidation of eroded organic matter (OM) rather than the Lena River serves as the predominant source of nutrients to the BKB. Atmospheric CO2 fluxes from the sea surface in the BKB vary from 1 to 95 mmol m-2 day-1 and are determined by specific features of hydrology and wind conditions, which change spatially, seasonally, and inter-annually. Mean values of CO2 emission from the shallow Laptev Sea were similar in September 1999 and 2005 (7.2 and 7.8 mmol m-2 day-1

  13. Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 2: Base Case and Sensitivity Analysis

    KAUST Repository

    Zhao, Zhenlong

    2013-01-17

    Part 1 (10.1021/ef3014103) of this series describes a new rotary reactor for gas-fueled chemical-looping combustion (CLC), in which, a solid wheel with microchannels rotates between the reducing and oxidizing streams. The oxygen carrier (OC) coated on the surfaces of the channels periodically adsorbs oxygen from air and releases it to oxidize the fuel. A one-dimensional model is also developed in part 1 (10.1021/ef3014103). This paper presents the simulation results based on the base-case design parameters. The results indicate that both the fuel conversion efficiency and the carbon separation efficiency are close to unity. Because of the relatively low reduction rate of copper oxide, fuel conversion occurs gradually from the inlet to the exit. A total of 99.9% of the fuel is converted within 75% of the channel, leading to 25% redundant length near the exit, to ensure robustness. In the air sector, the OC is rapidly regenerated while consuming a large amount of oxygen from air. Velocity fluctuations are observed during the transition between sectors because of the complete reactions of OCs. The gas temperature increases monotonically from 823 to 1315 K, which is mainly determined by the solid temperature, whose variations with time are limited within 20 K. The overall energy in the solid phase is balanced between the reaction heat release, conduction, and convective cooling. In the sensitivity analysis, important input parameters are identified and varied around their base-case values. The resulting changes in the model-predicted performance revealed that the most important parameters are the reduction kinetics, the operating pressure, and the feed stream temperatures. © 2012 American Chemical Society.

  14. Modeling the effects of anadromous fish nitrogen on the carbon balance of riparian forests in central Idaho

    Science.gov (United States)

    Noble Stuen, A. J.; Kavanagh, K.; Wheeler, T.

    2010-12-01

    Wild anadromous fish such as Pacific Chinook salmon (Oncorynchus tshawytscha) and steelhead (Oncorhyncus mykiss) were once abundant in Idaho, where they deposited their carcasses, rich in marine-derived nutrients (MDN), in the tributaries of the Columbia River. Anadromous fish are believed to have been a historically important nutrient source to the relatively nutrient-poor inland ecosystems of central Idaho, but no longer reach many inland watersheds due to presence of dams. This study investigates the multi-decadal cumulative effect of presence versus absence of anadromous fish nitrogen on net ecosystem exchange (NEE), or net carbon uptake, of riparian forests along historically salmon-bearing streams in the North Fork Boise River watershed, Idaho, in the context of a changing climate. The ecosystem process model BIOME-BGC is used to develop a representative forest ecosystem and predict the impact of decades of addition and continuing absence of MDN on NEE and net primary production (NPP). The study has 2 objectives: 1) to determine whether BIOME-BGC can reasonably simulate the riparian forests of central Idaho. A potentially confounding factor is the complex terrain of the region, particularly regarding soil water: water accumulation in valley bottoms and their riparian zones may lead to discrepancies in soil moisture and productivity of the riparian forest and of the simulations. The model is parameterized using local ecophysiology and site data and validated using field measurements of leaf area and soil moisture. Objective 2): to determine the effects on forest carbon balance and productivity of the presence or ongoing absence of anadromous-fish derived nitrogen. The forest simulation developed in objective 1 is run under two scenarios into the mid-20th century; one continuing without any supplemental nitrogen and one with nitrogen added in levels consistent with estimates of historical deposition by anadromous fish. Both scenarios incorporate warming due to

  15. Reduction of phosphate ores by carbon: Part I. Process variables for design of rotary kiln system

    Science.gov (United States)

    Mu, Jacob; Leder, Frederic; Park, Won C.; Hard, Robert A.; Megy, Joseph; Reiss, Howard

    1986-12-01

    Feasibility is established for the reduction of phosphate ores in a rotary kiln, avoiding electric submerged arc furnace technology. This represents a totally new approach to phosphoric acid. Reduction rates of phosphate ore-silica mixtures by carbon in the temperature range of 1100 to 1500 °C under several CO partial pressures in nitrogen were measured in thermogravimetric analyzers. Parameters such as carbon and silica contents, particle and pellet sizes, and gas flow rate were also evaluated with various domestic and foreign phosphate ores. Furthermore, a variety of carbon sources such as subbituminous coals, bituminous coals, anthracite, petroleum coke, and metallurgical coke were tested as reducing agents. Thermodynamic considerations elucidate the temperature dependence of overall conversion as well as the role of excess silica in establishing equilibrium pressure. These findings provide the background for analysis of the kinetics of conversion in Part II of this work. These studies, in conjunction with a previously published work, indicate the importance of intergranular melt phases in the kinetics of otherwise solid state reactions.

  16. Mechanical performance of carbon-epoxy laminates. Part I: quasi-static and impact bending properties

    Directory of Open Access Journals (Sweden)

    José Ricardo Tarpani

    2006-06-01

    Full Text Available In Part I of this study, quasi-static and impact bending properties of four aeronautical grade carbon-epoxy laminates have been determined and compared. Materials tested were unidirectional cross-ply (tape and bidirectional woven textile (fabric carbon fiber lay-up architectures, impregnated with standard and rubber-toughened resins, respectively, giving rise to 1.5 mm-thick laminates. Quasi-static mechanical properties assessed in transversal mode loading were modulus of elasticity, flexural strength and tenacity at the maximum load, whereas the net absorbed energy was determined under translaminar impact conditions. Two-dimensional woven carbon fiber reinforcements embedded in a rubber-toughened matrix presented the best mechanical performance under static loading. Under dynamic loading conditions, woven fiber fabric pre-forms were favorably sensitive to increasing impact energies regardless the nature of the employed epoxy resin. However, it was concluded that great care should be taken with this material within the low energy impact regimen.

  17. Carbon dioxide exchange of the Arctic tundra in the northern part of European Russia

    DEFF Research Database (Denmark)

    Kiepe, Isabell; Johansson, Paul Torbjörn; Friborg, Thomas

    Northern Russia has been subject to many speculations in relation to climatic change effects and greenhouse gas (GHG) exchange but still little scientific evidence is available for this region. There is low abundance of continuous Arctic GHG exchange measurements deploying eddy covariance technique...... 70 cm in the hummocky areas. The climate is continental with a mean annual air temperature (1995-2007) of about -9.4 °C (Vorkuta). To determine the greenhouse balance of this area the eddy covariance technique was used in the late period of the growing season of 2007. In this study we focus...... on the transition period at the end of the growth season, which is a part of the year when predicted changes in temperature is likely to have the most pronounced effects on the exchange of GHGs. The net ecosystem CO2 exchange reflects two important influences on the opposed fluxes, gross photosynthesis...

  18. Long-term nutrient fertilization and the carbon balance of permanent grassland: any evidence for sustainable intensification?

    Science.gov (United States)

    Fornara, Dario A.; Wasson, Elizabeth-Anne; Christie, Peter; Watson, Catherine J.

    2016-09-01

    Sustainable grassland intensification aims to increase plant yields while maintaining the ability of soil to act as a sink rather than sources of atmospheric CO2. High biomass yields from managed grasslands, however, can be only maintained through long-term nutrient fertilization, which can significantly affect soil carbon (C) storage and cycling. Key questions remain about (1) how long-term inorganic vs. organic fertilization influences soil C stocks, and (2) how soil C gains (or losses) contribute to the long-term C balance of managed grasslands. Using 43 years of data from a permanent grassland experiment, we show that soils not only act as significant C sinks but have not yet reached C saturation. Even unfertilized control soils showed C sequestration rates of 0.35 Mg C ha-1 yr-1 (i.e. 35 g C m-2 yr-1; 0-15 cm depth) between 1970 and 2013. High application rates of liquid manure (i.e. cattle slurry) further increased soil C sequestration to 0.86 Mg C ha-1 yr-1 (i.e. 86 g C m-2 yr-1) and a key cause of this C accrual was greater C inputs from cattle slurry. However, average coefficients of slurry-C retention in soils suggest that 85 % of C added yearly through liquid manure is lost possibly via CO2 fluxes and organic C leaching. Inorganically fertilized soils (i.e. NPK) had the lowest C-gain efficiency (i.e. unit of C gained per unit of N added) and lowest C sequestration (similar to control soils). Soils receiving cattle slurry showed higher C-gain and N-retention efficiencies compared to soils receiving NPK or pig slurry. We estimate that net rates of CO2-sequestration in the top 15 cm of the soil can offset 9-25 % of GHG (greenhouse gas) emissions from intensive management. However, because of multiple GHG sources associated with livestock farming, the net C balance of these grasslands remains positive (9-12 Mg CO2-equivalent ha-1 yr-1), thus contributing to climate change. Further C-gain efficiencies (e.g. reduced enteric fermentation and use of feed

  19. The carbon balance of reducing wildfire risk and restoring process: an analysis of 10-year post-treatment carbon dynamics in a mixed-conifer forest

    Science.gov (United States)

    Morgan L. Wiechmann; Matthew D. Hurteau; Malcolm P. North; George W. Koch; Lucie Jerabkova

    2015-01-01

    Forests sequester carbon from the atmosphere, helping mitigate climate change. In fire-prone forests, burn events result in direct and indirect emissions of carbon. High fire-induced tree mortality can cause a transition from a carbon sink to source, but thinning and prescribed burning can reduce fire severity and carbon loss when wildfire occurs. However, treatment...

  20. Greenland Surface Mass Balance as Simulated by the Community Earth System Model. Part II: Twenty-First-Century Changes

    NARCIS (Netherlands)

    Vizcaino, M.; Lipscomb, W.H.; Sacks, W.J.; van den Broeke, M.R.

    2014-01-01

    This study presents the first twenty-first-century projections of surface mass balance (SMB) changes for the Greenland Ice Sheet (GIS) with the Community Earth System Model (CESM), which includes a new ice sheet component. For glaciated surfaces, CESM includes a sophisticated calculation of energy

  1. Mass, energy and material balances of SRF production process. Part 2: SRF produced from construction and demolition waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-11-01

    In this work, the fraction of construction and demolition waste (C&D waste) complicated and economically not feasible to sort out for recycling purposes is used to produce solid recovered fuel (SRF) through mechanical treatment (MT). The paper presents the mass, energy and material balances of this SRF production process. All the process streams (input and output) produced in MT waste sorting plant to produce SRF from C&D waste are sampled and treated according to CEN standard methods for SRF. Proximate and ultimate analysis of these streams is performed and their composition is determined. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. By mass balance means the overall mass flow of input waste material stream in the various output streams and material balances mean the mass flow of components of input waste material stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. The results from mass balance of SRF production process showed that of the total input C&D waste material to MT waste sorting plant, 44% was recovered in the form of SRF, 5% as ferrous metal, 1% as non-ferrous metal, and 28% was sorted out as fine fraction, 18% as reject material and 4% as heavy fraction. The energy balance of this SRF production process showed that of the total input energy content of C&D waste material to MT waste sorting plant, 74% was recovered in the form of SRF, 16% belonged to the reject material and rest 10% belonged to the streams of fine fraction and heavy fraction. From the material balances of this process, mass fractions of plastic (soft), paper and cardboard, wood and plastic (hard) recovered in the SRF stream were 84%, 82%, 72% and 68% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC) and rubber material was found in the reject material

  2. Mass, energy and material balances of SRF production process. Part 1: SRF produced from commercial and industrial waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-08-01

    This paper presents the mass, energy and material balances of a solid recovered fuel (SRF) production process. The SRF is produced from commercial and industrial waste (C&IW) through mechanical treatment (MT). In this work various streams of material produced in SRF production process are analyzed for their proximate and ultimate analysis. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. Here mass balance describes the overall mass flow of input waste material in the various output streams, whereas material balance describes the mass flow of components of input waste stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. A commercial scale experimental campaign was conducted on an MT waste sorting plant to produce SRF from C&IW. All the process streams (input and output) produced in this MT plant were sampled and treated according to the CEN standard methods for SRF: EN 15442 and EN 15443. The results from the mass balance of SRF production process showed that of the total input C&IW material to MT waste sorting plant, 62% was recovered in the form of SRF, 4% as ferrous metal, 1% as non-ferrous metal and 21% was sorted out as reject material, 11.6% as fine fraction, and 0.4% as heavy fraction. The energy flow balance in various process streams of this SRF production process showed that of the total input energy content of C&IW to MT plant, 75% energy was recovered in the form of SRF, 20% belonged to the reject material stream and rest 5% belonged with the streams of fine fraction and heavy fraction. In the material balances, mass fractions of plastic (soft), plastic (hard), paper and cardboard and wood recovered in the SRF stream were 88%, 70%, 72% and 60% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC), rubber material and non

  3. A qualitative investigation of specialist orthodontists in New Zealand: part 2. Orthodontists' working lives and work-life balance.

    Science.gov (United States)

    Soma, Kieran J; Thomson, W Murray; Morgaine, Kate C; Harding, Winifred J

    2012-11-01

    Orthodontics is the most widely practised form of specialist dentistry in New Zealand. To date, no known qualitative research has been published examining the work-life balance of practitioners. The aim of this study was to investigate the working lives and work-life balance of NZ orthodontists in order to generate an understanding of the reality of orthodontic specialist practice and its effects on orthodontists' professional and personal lives. Semi-structured interviews were conducted involving 19 practising orthodontists (four females, 15 males; mean age 50 years) from throughout New Zealand and selected for maximum variation in the sample. Transcribed interviews were analysed for themes using an applied grounded theory approach. A core category of 'practising orthodontist' was derived, and related themes were grouped under the sub-categories of: (a) NZ orthodontic specialist practice; (b) NZ specialist orthodontists; and (c) Work-life balance. The present paper reports on the final sub-category. Themes emerging from the work-life sub-category were further divided into two sub-themes of 'work' and 'life'. Themes in the 'work' subgroup included time off, injuries and illness, regrets, personality traits, job stress and criticism, establishing a practice, peer support and contact, and success in orthodontics. Themes in the 'life' sub-group were personal development, family life, life balance and interests outside work, and financial security. This was the first qualitative investigation of the orthodontic profession in New Zealand. The findings provided a valuable insight into the working lives of New Zealand orthodontists and effects on their day-today lives. It will be revealing and interesting to observe how the modernisation of orthodontic practice will affect the work-life balance of New Zealand orthodontists in the future.

  4. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

    Energy Technology Data Exchange (ETDEWEB)

    B.E. Law; D. Turner; M. Goeckede

    2010-06-01

    GOAL: To develop and apply an approach to quantify and understand the regional carbon balance of the west coast states for the North American Carbon Program. OBJECTIVE: As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance. APPROACH: In performing the regional analysis, the research plan for the bottom-up approach uses a nested hierarchy of observations that include AmeriFlux data (i.e., net ecosystem exchange (NEE) from eddy covariance and associated biometric data), intermediate intensity inventories from an extended plot array partially developed from the PI's previous research, Forest Service FIA and CVS inventory data, time since disturbance, disturbance type, and cover type from Landsat developed in this study, and productivity estimates from MODIS algorithms. The BIOME-BGC model is used to integrate information from these sources and quantify C balance across the region. The inverse modeling approach assimilates flux data from AmeriFlux sites, high precision CO2 concentration data from AmeriFlux towers and four new calibrated CO2 sites

  5. The effects of land cover and land use change on the contemporary carbon balance of the arctic and boreal terrestrial ecosystems of northern Eurasia

    Science.gov (United States)

    Hayes, Daniel J.; McGuire, A. David; Kicklighter, David W.; Burnside , Todd J.; Melillo, Jerry M.

    2010-01-01

    Recent changes in climate, disturbance regimes and land use and management systems in Northern Eurasia have the potential to disrupt the terrestrial sink of atmospheric CO2 in a way that accelerates global climate change. To determine the recent trends in the carbon balance of the arctic and boreal ecosystems of this region, we performed a retrospective analysis of terrestrial carbon dynamics across northern Eurasia over a recent 10-year period using a terrestrial biogeochemical process model. The results of the simulations suggest a shift in direction of the net flux from the terrestrial sink of earlier decades to a net source on the order of 45 Tg C year−1between 1997 and 2006. The simulation framework and subsequent analyses presented in this study attribute this shift to a large loss of carbon from boreal forest ecosystems, which experienced a trend of decreasing precipitation and a large area burned during this time period.

  6. FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS - part I: TYPES OF CNs

    Directory of Open Access Journals (Sweden)

    Cătălin IANCU

    2012-05-01

    Full Text Available In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. In this review paper are presented some of the most important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. The synthesis techniques are used to produce specific kinds of low-dimensional carbon nanomaterials such as zero-dimensional CNs (including fullerene, carbon-encapsulated metal nanoparticles, nanodiamond, and onion-like carbons, one-dimensional carbon nanomaterials (including carbon nanofibers and carbon nanotubes, and two-dimensional carbon nanomaterials (including graphene and carbon nanowalls.

  7. Ash recycling to spruce and beech stands effects on nutrients, growth, nitrogen dynamics and carbon balance; Askaaterfoering till gran- och bokbestaand - effekter paa naering, tillvaext, kvaevedynamik och kolbalans

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2006-03-15

    Ash recycling is an important part in a modern, sustainable forestry, especially in whole-tree harvest systems. Nutrients lost at harvest are returned to the forest with the wood-ash. In the project the effects of ash treatment on needle and leaf chemistry, tree growth, soil chemistry, soil water chemistry, and carbon and nitrogen dynamics were studied on 23 Norway spruce sites in south-western Sweden and in ten European beech sites in Scania, southern Sweden. On some of the sites there were previously established ash recycling experiments, but on a majority of the sites ash recycling was performed without experimental lay-out and ash and control plots were established afterwards. The most common dose was two tons of self hardened crushed wood-ash and two tons of Mg-lime. On average seven to eight years after ash recycling the results were 1. increased exchangeable stores of base cations in the soil in the beech and the spruce stands 2. increased base saturation in the beech and the spruce stands and increased BC/Al in the spruce stands 3. increased concentrations and ratios to N of P, Ca, Zn, and S in the needles, the increased P-values are especially important since P is close to or below deficiency levels in a majority of the spruce stands 4. decreased K-concentration in the beech leaves 5. increased tree growth with on average 14 % in the ash treated spruce stands compared to the control plots 6. increased carbon and nitrogen amounts in the biomass in the spruce stands 7. tendencies towards increased amounts of carbon and nitrogen in the soil in the beech stands and no effect in the soil in the spruce stands 8. increased concentrations of Ca, Mg, and SO{sub 4} and no effect on ANC in the soil water 9. no effect on potential net mineralization but increased potential nitrification rates 10. decreased concentration of nitrate in the soil water in the beech stands and no effect in the spruce stands 11. lower system N losses in the beech stands and possibly in the

  8. Investigations and researches on CO2 balance in a high-temperature carbon dioxide separation technology; Nisanka tanso koon bunri gijutsu ni okeru CO2 balance ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    With an objective to select a promising process by comparing application environments and effectiveness of a high-temperature carbon dioxide separation, recovery and re-utilization technology with other methods, investigations were performed on reducible amount of carbon dioxide discharge by using material balance and system introduction. A large number of chemical and physical technologies are being developed for the separation and refining methods. This paper discusses the technologies for their application to iron and steel making, oil refining, and petrochemical industries, the so-called heavy and large product industries. As a possibility of utilizing the high-temperature separated CO2 in iron and steel making, an investigation was given on the direct iron ore smelting reduction process. It would be unreasonable to use CO2 in oil refining as a substitute to air to regenerate a catalytic decomposition and reformation catalyst because of decline in the catalytic activity. A discussion was given on a case to replace steam with CO2 in steam reformation and pyrolysis of hydrocarbons. The discussion requires the objective to be focused on such items as C/H ratio at a reformer outlet and relationship of balance in decomposition products. The C1 chemical and others were reviewed to search possibilities for their use as raw materials of chemicals used in chemical industries. Possibilities were discussed to fix high-temperature CO2 into peridotite and serpentine. 42 refs., 32 figs., 11 tabs.

  9. Synthesis of Remote Sensing and Field Observations to Model and Understand Disturbance and Climate Effects on the Carbon Balance of Oregon & Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Beverly Law; David Turner; Warren Cohen; Mathias Goeckede

    2008-05-22

    The goal is to quantify and explain the carbon (C) budget for Oregon and N. California. The research compares "bottom -up" and "top-down" methods, and develops prototype analytical systems for regional analysis of the carbon balance that are potentially applicable to other continental regions, and that can be used to explore climate, disturbance and land-use effects on the carbon cycle. Objectives are: 1) Improve, test and apply a bottom up approach that synthesizes a spatially nested hierarchy of observations (multispectral remote sensing, inventories, flux and extensive sites), and the Biome-BGC model to quantify the C balance across the region; 2) Improve, test and apply a top down approach for regional and global C flux modeling that uses a model-data fusion scheme (MODIS products, AmeriFlux, atmospheric CO2 concentration network), and a boundary layer model to estimate net ecosystem production (NEP) across the region and partition it among GPP, R(a) and R(h). 3) Provide critical understanding of the controls on regional C balance (how NEP and carbon stocks are influenced by disturbance from fire and management, land use, and interannual climate variation). The key science questions are, "What are the magnitudes and distributions of C sources and sinks on seasonal to decadal time scales, and what processes are controlling their dynamics? What are regional spatial and temporal variations of C sources and sinks? What are the errors and uncertainties in the data products and results (i.e., in situ observations, remote sensing, models)?

  10. Projecting the past and future impacts of hurricanes on the carbon balance of eastern U.S. forests (1851-2100)

    Science.gov (United States)

    Fisk, J.; Hurtt, G. C.; Chambers, J. Q.; Zeng, H.

    2009-12-01

    In U.S. Atlantic coastal areas, hurricanes are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Estimates of the carbon emissions resulting from single storms range as high as ~100 Tg C, an amount equivalent to the annual U.S. carbon sink in forest trees. Recent studies have estimated the historic regional carbon emissions from hurricane activity using an empirically based approach. Here, we use a mechanistic ecosystem model, the Ecosystem Demography (ED) model, driven by maps of mortality and damage based on historic hurricane tracks and future scenarios to predict the past and future impacts of hurricanes on the carbon balance of eastern U.S. forests. Model estimates compare well to previous empirically based estimates, with mean annual biomass loss of 26 Tg C yr-1 (range 0 to ~225 Tg C yr-1) resulting from hurricanes during the period 1851-2000. Using the mechanistic model, we are able to include the effects of both disturbance and recovery on the net carbon flux. We find a regional carbon sink throughout much of the 20th century resulting from forest recovery following a peak in hurricane activity during the late 19th century exceeding biomass loss. Recent increased hurricane activity has resulted in the region becoming a net carbon source. For the future, several recent studies have linked increased sea surface temperatures expected with climate change to increased hurricane activity. Based on these relationships, we investigate a range of scenarios of future hurricane activity and find the potential for substantial increases in emissions from hurricane mortality and reductions in regional carbon stocks. In our scenario with the largest increase in hurricane activity, we find a 35% increase in area disturbed by 2100, but due to the reduction of standing biomass, only a 20% increase in biomass loss per year. Developing this kind of predictive modeling capability that tracks disturbance events and

  11. Detecting management and fertilization effects on the carbon balance of winter oilseed rape with manual closed chamber measurements: Can we outrange gap-filling uncertainty and spatiotemporal variability?

    Science.gov (United States)

    Huth, Vytas; Moffat, Antje Maria; Calmet, Anna; Andres, Monique; Laufer, Judit; Pehle, Natalia; Rach, Bernd; Gundlach, Laura; Augustin, Jürgen

    2017-04-01

    Winter oilseed rape is the dominant biofuel crop in the young moraine landscape in North-Eastern Germany. However, studies on the effect of rapeseed cropping on net ecosystem exchange of CO2 (NEE) and the soil carbon (SC) balance are scarce. SC balance estimates are usually derived from long-term soil sampling field trials where rapeseed is part of different crop rotations. The estimated annual differences linked to rapeseed cropping are rather small (varying between losses of 40 g C m-2 and gains of up to 100 g C m-2). Testing management effects on the NEE and SC balance of cropping systems is best done by comparing plots with different treatments at the same site under the same climate. The soil sampling approach is in the need of field trials that run over decades, which has the disadvantage that management strategies of practical farming may have already changed when the results are derived. Continuous eddy covariance measurements of NEE would require large fields in flat terrain for each of the treatments, which is especially complicated in the heterogeneous landscapes of glacigenic origin of North-Eastern Germany. The common approach of using the chamber technique to derive NEE, however, is subject to the local soil and plant stand heterogeneities due to its tiny footprint. This technique might also disturb the ecosystem, the measurements are usually discontinuous requiring elaborate gap-filling techniques, and it has mostly been used on organic soils where large respiratory C losses occur. Therefore, our aim was to answer, if a combined approach of the eddy covariance and the chamber technique can detect the relatively small NEE and SC differences of rapeseed cropping on mineral soils within a shorter period of time than conventional soil sampling field trials can. We tested the new experimental design taking the advantages of both techniques into account: The eddy covariance tower measuring the NEE dynamics during the year; the chamber measurements to

  12. Modelling the climate and surface mass balance of polar ice sheets using RACMO2 - Part 1: Greenland (1958-2016)

    Science.gov (United States)

    Noël, Brice; van de Berg, Willem Jan; Melchior van Wessem, J.; van Meijgaard, Erik; van As, Dirk; Lenaerts, Jan T. M.; Lhermitte, Stef; Kuipers Munneke, Peter; Smeets, C. J. P. Paul; van Ulft, Lambertus H.; van de Wal, Roderik S. W.; van den Broeke, Michiel R.

    2018-03-01

    We evaluate modelled Greenland ice sheet (GrIS) near-surface climate, surface energy balance (SEB) and surface mass balance (SMB) from the updated regional climate model RACMO2 (1958-2016). The new model version, referred to as RACMO2.3p2, incorporates updated glacier outlines, topography and ice albedo fields. Parameters in the cloud scheme governing the conversion of cloud condensate into precipitation have been tuned to correct inland snowfall underestimation: snow properties are modified to reduce drifting snow and melt production in the ice sheet percolation zone. The ice albedo prescribed in the updated model is lower at the ice sheet margins, increasing ice melt locally. RACMO2.3p2 shows good agreement compared to in situ meteorological data and point SEB/SMB measurements, and better resolves the spatial patterns and temporal variability of SMB compared with the previous model version, notably in the north-east, south-east and along the K-transect in south-western Greenland. This new model version provides updated, high-resolution gridded fields of the GrIS present-day climate and SMB, and will be used for projections of the GrIS climate and SMB in response to a future climate scenario in a forthcoming study.

  13. Modelling the climate and surface mass balance of polar ice sheets using RACMO2 - Part 2: Antarctica (1979-2016)

    Science.gov (United States)

    Melchior van Wessem, Jan; van de Berg, Willem Jan; Noël, Brice P. Y.; van Meijgaard, Erik; Amory, Charles; Birnbaum, Gerit; Jakobs, Constantijn L.; Krüger, Konstantin; Lenaerts, Jan T. M.; Lhermitte, Stef; Ligtenberg, Stefan R. M.; Medley, Brooke; Reijmer, Carleen H.; van Tricht, Kristof; Trusel, Luke D.; van Ulft, Lambertus H.; Wouters, Bert; Wuite, Jan; van den Broeke, Michiel R.

    2018-04-01

    We evaluate modelled Antarctic ice sheet (AIS) near-surface climate, surface mass balance (SMB) and surface energy balance (SEB) from the updated polar version of the regional atmospheric climate model, RACMO2 (1979-2016). The updated model, referred to as RACMO2.3p2, incorporates upper-air relaxation, a revised topography, tuned parameters in the cloud scheme to generate more precipitation towards the AIS interior and modified snow properties reducing drifting snow sublimation and increasing surface snowmelt. Comparisons of RACMO2 model output with several independent observational data show that the existing biases in AIS temperature, radiative fluxes and SMB components are further reduced with respect to the previous model version. The model-integrated annual average SMB for the ice sheet including ice shelves (minus the Antarctic Peninsula, AP) now amounts to 2229 Gt y-1, with an interannual variability of 109 Gt y-1. The largest improvement is found in modelled surface snowmelt, which now compares well with satellite and weather station observations. For the high-resolution ( ˜ 5.5 km) AP simulation, results remain comparable to earlier studies. The updated model provides a new, high-resolution data set of the contemporary near-surface climate and SMB of the AIS; this model version will be used for future climate scenario projections in a forthcoming study.

  14. Elevated CO2-mitigation of high temperature stress associated with maintenance of positive carbon balance and carbohydrate accumulation in Kentucky bluegrass.

    Science.gov (United States)

    Song, Yali; Yu, Jingjin; Huang, Bingru

    2014-01-01

    Elevated CO2 concentration may promote plant growth while high temperature is inhibitory for C3 plant species. The interactive effects of elevated CO2 and high temperatures on C3 perennial grass growth and carbon metabolism are not well documented. Kentucky bluegrass (Poa pratensis) plants were exposed to two CO2 levels (400 and 800 μmol mol-1) and five temperatures (15/12, 20/17, 25/22, 30/27, 35/32°C, day/night) in growth chambers. Increasing temperatures to 25°C and above inhibited leaf photosynthetic rate (Pn) and shoot and root growth, but increased leaf respiration rate (R), leading to a negative carbon balance and a decline in soluble sugar content under ambient CO2. Elevated CO2 did not cause shift of optimal temperatures in Kentucky bluegrass, but promoted Pn, shoot and root growth under all levels of temperature (15, 20, 25, 30, and 35°C) and mitigated the adverse effects of severe high temperatures (30 and 35°C). Elevated CO2-mitigation of adverse effects of high temperatures on Kentucky bluegrass growth could be associated with the maintenance of a positive carbon balance and the accumulation of soluble sugars and total nonstructural carbohydrates through stimulation of Pn and suppression of R and respiratory organic acid metabolism.

  15. Carbon balance assessment by eddy covariance method for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils of Russia

    Science.gov (United States)

    Meshalkina, J. L.; Yaroslavtsev, A. M.; Vasenev, I. I.; Andreeva, I. V.; Tihonova, M. V.

    2018-01-01

    The carbon balance for the agroecosystems with potato plants and oats & vetch mixture on sod-podzolics soils was evaluated using the eddy covariance approach. Absorption of carbon was recorded only during the growing season; maximum values were detected for all crops in July. The number of days during the vegetation period, when the carbon stocked in the fields with potatoes and oats & vetch mixture was about the same and accounted for 53-55 days. During this period, the increase in gross primary production (GPP) is well correlated with the crop yields. The curve of the gross primary productivity is closely linked to the phases of development of plants; for potatoes, this graph differs significantly for all phases. Form of oats & vetch mixture biomass curve shown linear increases. Carbon losses were observed for all the studied agroecosystems: for fields with an oats & vetch mixture they were 254 g C m-2 y-1, while for fields with potato plants they were 307 g C m-2 y-1. Values about 250-300 g C m-2 per year may be considered as estimated values for the total carbon uptake for agroecosystems with potato plants and oats & vetch mixture on sod-podzolic soils.

  16. Conductive additive content balance in Li-ion battery cathodes: Commercial carbon blacks vs. in situ carbon from LiFePO{sub 4}/C composites

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, Veronica; Goni, Aintzane; Muro, Izaskun Gil de; Rojo, Teofilo [Departamento de Quimica Inorganica, Universidad del Pais Vasco UPV/EHU, P.O. Box. 644, 48080, Bilbao (Spain); de Meatza, Iratxe; Bengoechea, Miguel [Energy Department, CIDETEC-IK4, P Miramon 196, Parque Tecnologico de San Sebastian, 20009, San Sebastian (Spain); Cantero, Igor [Departamento I+D+i Nuevas Tecnologias, CEGASA, Artapadura, 11, 01013 Vitoria-Gasteiz (Spain)

    2010-11-15

    Two samples of commercial conducting carbon black and the carbon generated in situ during LiFePO{sub 4}/C composite synthesis from citric acid are studied, with the aim of finding out whether carbon from the composite can fulfil the same function as carbon black in the electrode blend for a Li-ion battery. For this purpose, the carbon samples are analyzed by several techniques, such as X-ray diffraction, Raman spectroscopy, transmission electron microscopy, granulometry, BET specific area and conductivity measurements. Different cathode compositions and component proportions are tested for pellet and cast electrodes. Electrochemical results show that a moderate reduction of commercial carbon black content in both kinds of cathodes, by adding more LiFePO{sub 4}/C composite, enhanced the electrochemical behaviour by around 10%. In situ generated carbon can partially replace commercial conducting carbon black because its high specific surface probably enhances electrolyte penetration into the cathode, but it is always necessary to maintain a minimum amount of carbon black that provides better conductivity in order to obtain a good electrochemical response. (author)

  17. Simulating groundwater flow and runoff for the Oro Moraine aquifer system. Part II. Automated calibration and mass balance calculations

    Science.gov (United States)

    Beckers, J.; Frind, E. O.

    2001-03-01

    A steady-state groundwater model of the Oro Moraine aquifer system in Central Ontario, Canada, is developed. The model is used to identify the role of baseflow in the water balance of the Minesing Swamp, a 70 km 2 wetland of international significance. Lithologic descriptions are used to develop a hydrostratigraphic conceptual model of the aquifer system. The numerical model uses long-term averages to represent temporal variations of the flow regime and includes a mechanism to redistribute recharge in response to near-surface geologic heterogeneity. The model is calibrated to water level and streamflow measurements through inverse modeling. Observed baseflow and runoff quantities validate the water mass balance of the numerical model and provide information on the fraction of the water surplus that contributes to groundwater flow. The inverse algorithm is used to compare alternative model zonation scenarios, illustrating the power of non-linear regression in calibrating complex aquifer systems. The adjoint method is used to identify sensitive recharge areas for groundwater discharge to the Minesing Swamp. Model results suggest that nearby urban development will have a significant impact on baseflow to the swamp. Although the direct baseflow contribution makes up only a small fraction of the total inflow to the swamp, it provides an important steady influx of water over relatively large portions of the wetland. Urban development will also impact baseflow to the headwaters of local streams. The model provides valuable insight into crucial characteristics of the aquifer system although definite conclusions regarding details of its water budget are difficult to draw given current data limitations. The model therefore also serves to guide future data collection and studies of sub-areas within the basin.

  18. Effect of Multiwalled Carbon Nanotubes on the Mechanical Properties of Carbon Fiber-Reinforced Polyamide-6/Polypropylene Composites for Lightweight Automotive Parts

    Directory of Open Access Journals (Sweden)

    Huu-Duc Nguyen-Tran

    2018-03-01

    Full Text Available The development of lightweight automotive parts is an important issue for improving the efficiency of vehicles. Polymer composites have been widely applied to reduce weight and improve mechanical properties by mixing polymers with carbon fibers, glass fibers, and carbon nanotubes. Polypropylene (PP has been added to carbon fiber-reinforced nylon-6 (CF/PA6 composite to achieve further weight reduction and water resistance. However, the mechanical properties were reduced by the addition of PP. In this research, multiwalled carbon nanotubes (CNTs were added to compensate for the reduced mechanical properties experienced when adding PP. Tensile testing and bending tests were carried out to evaluate the mechanical properties. A small amount of CNTs improved the mechanical properties of carbon fiber-reinforced PA6/PP composites. For example, the density of CF/PA6 was reduced from 1.214 to 1.131 g/cm3 (6.8% by adding 30 wt % PP, and the tensile strength of 30 wt % PP composite was improved from 168 to 173 MPa (3.0% by adding 0.5 wt % CNTs with small increase of density (1.135 g/cm3. The developed composite will be widely used for lightweight automotive parts with improved mechanical properties.

  19. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul; Loveland, Thomas R.

    2018-01-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr−1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr−1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr−1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  20. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul C.; Loveland, Thomas R.

    2018-04-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr‑1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr‑1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr‑1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  1. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    DEFF Research Database (Denmark)

    Filgueira, Ramón; Byron, C.J.; Comeau, L.A.

    2015-01-01

    , is needed to provide a rigorous assessment of the role of bivalve mariculture in the CO2 cycle. On the other hand, the discussion about the inclusion of shells of cultured bivalves into the carbon trading system should be framed in the context of ecosystem goods and services. Humans culture bivalves......The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities...... with the aim of producing food, not sequestering CO2 in their shells, therefore the main ecosystem good provided by bivalve aquaculture is meat production, and shells should be considered as by-products of this human activity. This reasoning is key to split the CO2 released due to respiration between meat...

  2. Both sulfate-reducing bacteria and Enterobacteriaceae take part in marine biocorrosion of carbon steel.

    Science.gov (United States)

    Bermont-Bouis, D; Janvier, M; Grimont, P A D; Dupont, I; Vallaeys, T

    2007-01-01

    In order to evaluate the part played in biocorrosion by microbial groups other than sulfate-reducing bacteria (SRB), we characterized the phylogenetic diversity of a corrosive marine biofilm attached to a harbour pile structure as well as to carbon steel surfaces (coupons) immersed in seawater for increasing time periods (1 and 8 months). We thus experimentally checked corroding abilities of defined species mixtures. Microbial community analysis was performed using both traditional cultivation techniques and polymerase chain reaction cloning-sequencing of 16S rRNA genes. Community structure of biofilms developing with time on immersed coupons tended to reach after 8 months, a steady state similar to the one observed on a harbour pile structure. Phylogenetic affiliations of isolates and cloned 16S rRNA genes (rrs) indicated that native biofilms (developing after 1-month immersion) were mainly colonized by gamma-proteobacteria. Among these, Vibrio species were detected in majority with molecular methods while cultivation techniques revealed dominance of Enterobacteriaceae such as Citrobacter, Klebsiella and Proteus species. Conversely, in mature biofilms (8-month immersion and pile structure), SRB, and to a lesser extent, spirochaetes were dominant. Corroding activity detection assays confirmed that Enterobacteriaceae (members of the gamma-proteobacteria) were involved in biocorrosion of metallic material in marine conditions. In marine biofilms, metal corrosion may be initiated by Enterobacteriaceae.

  3. Disturbance and the Carbon Balance of US Forests: A Quantitative Review of Impacts from Harvests, Fires, Insects, and Droughts

    Science.gov (United States)

    Williams, Christopher A.; Gu, Huan; MacLean, Richard; Masek, Jeffrey G.; Collatz, G. James

    2016-01-01

    Disturbances are a major determinant of forest carbon stocks and uptake. They generally reduce land carbon stocks but also initiate a regrowth legacy that contributes substantially to the contemporary rate of carbon stock increase in US forestlands. As managers and policy makers increasingly look to forests for climate protection and mitigation, and because of increasing concern about changes in disturbance intensity and frequency, there is a need for synthesis and integration of current understanding about the role of disturbances and other processes in governing forest carbon cycle dynamics, and the likely future of this and other sinks for atmospheric carbon. This paper aims to address that need by providing a quantitative review of the distribution, extent and carbon impacts of the major disturbances active in the US. We also review recent trends in disturbances, climate, and other global environmental changes and consider their individual and collective contributions to the US carbon budget now and in the likely future. Lastly, we identify some key challenges and opportunities for future research needed to improve current understanding, advance predictive capabilities, and inform forest management in the face of these pressures. Harvest is found to be the most extensive disturbance both in terms of area and carbon impacts, followed by fire, windthrow and bark beetles, and lastly droughts. Collectively these lead to the gross loss of about 200 Tg C y(exp -1) in live biomass annually across the conterminous US. At the same time, the net change in forest carbon stocks is positive (190 Tg C y(exp -1)), indicating not only forest resilience but also an apparently large response to growth enhancements such as fertilization by CO2 and nitrogen. Uncertainty about disturbance legacies, disturbance interactions, likely trends, and global change factors make the future of the US forest carbon sink unclear. While there is scope for management to enhance carbon sinks in US

  4. Quantitative Estimation of Soil Carbon Sequestration in Three Land Use Types (Orchard, Paddy Rice and Forest in a Part of Ramsar Lands, Northern Iran

    Directory of Open Access Journals (Sweden)

    zakieh pahlavan yali

    2017-02-01

    Full Text Available Introduction: The increasing Greenhouse Gases in atmosphere is the main cause of climate and ecosystems changes. The most important greenhouse gas is CO2 that causes global warming or the greenhouse effect. One of the known solutions that reduces atmospheric carbon and helps to improve the situation, is carbon sequestration in vegetation cover and soil. Carbon sequestration refers to the change in atmospheric CO2 into organic carbon compounds by plants and capture it for a certain time . However, the ecosystems with different vegetation have Impressive Influence on soil carbon sequestration (SCS. Soil as the main component of these ecosystems is a world-wide indicator which has been known to play an important role in global balance of carbon sequestration. Furthermore, carbon sequestration can be a standard world trade and becomes guaranteed. Costs of transfer of CO2 (carbon transfer From the atmosphere into the soil based on the negative effects of increased CO2 on Weather is always increasing, This issue can be faced by developing countries to create a new industry, especially when conservation and restoration of rangeland to follow. This research was regarded due to estimation of SCS in three land use types (orchard, paddy rice and forest in a Part of Ramsar Lands, Northern Iran. Materials and Methods: Ramsar city with an area of about 729/7 km2 is located in the western part of Mazandaran province. Its height above sea level is 20 meters. Ramsar city is situated in a temperate and humid climate. Land area covered by forest, orchard and paddy rice. After field inspection of the area, detailed topographic maps of the specified zone on the study were also tested. In each of the three land types, 500 hectares in the every growing and totally 1,500 hectares as study area were selected .For evaluation the sequestration of carbon in different vegetation systems,15 soil profile selected and sampling from depth of 0 to 100 centimetres of each profile

  5. The influence of broiler activity, growth rate, and litter on carbon dioxide balances for the determination of ventilation flow rates in broiler production.

    Science.gov (United States)

    Calvet, S; Estellés, F; Cambra-López, M; Torres, A G; Van den Weghe, H F A

    2011-11-01

    Carbon dioxide balances are useful in determining ventilation rates in livestock buildings. These balances need an accurate estimation of the CO(2) produced by animals and their litter to determine the ventilation flows. To estimate the daily variation in ventilation flow, it is necessary to precisely know the daily variation pattern of CO(2) production, which mainly depends on animal activity. The objective of this study was to explore the applicability of CO(2) balances for determining ventilation flows in broiler buildings. More specifically, this work aimed to quantify the amount of CO(2) produced by the litter, as well as the amount of CO(2) produced by the broilers, as a function of productive parameters, and to analyze the influence of broiler activity on CO(2) emissions. Gas concentrations and ventilation flows were simultaneously measured in 3 trials, with 1 under experimental conditions and the other 2 in a commercial broiler farm. In the experimental assay, broiler activity was also determined. At the end of the experimental trial, on the day after the removal of the broilers, the litter accounted for 20% of the total CO(2) produced, and the broilers produced 3.71 L/h of CO(2) per kg of metabolic weight. On the commercial farm, CO(2) production was the same for the 2 cycles (2.60 L/h per kg of metabolic weight, P > 0.05). However, substantial differences were found between CO(2) and broiler activity patterns after changes in light status. A regression model was used to explain these differences (R(2) = 0.52). Carbon dioxide increased with bird activity, being on average 3.02 L/h per kg of metabolic weight for inactive birds and 4.73 L/h per kg of metabolic weight when bird activity was highest. Overall, CO(2) balances are robust tools for determining the daily average ventilation flows in broiler farms. These balances could also be applied at more frequent intervals, but in this case, particular care is necessary after light status changes because of

  6. Net ecosystem production and organic carbon balance of U.S. East Coast estuaries: A synthesis approach

    Science.gov (United States)

    Herrmann, Maria; Najjar, Raymond G.; Kemp, W. Michael; Alexander, Richard B.; Boyer, Elizabeth W.; Cai, Wei-Jun; Griffith, Peter C.; Kroeger, Kevin D.; McCallister, S. Leigh; Smith, Richard A.

    2015-01-01

    Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic carbon, and carbon burial in the sediment to estuarine water residence time and total nitrogen input across the landward boundary. Output from a data-constrained water quality model was used to estimate inputs of total nitrogen and organic carbon to the estuaries across the landward boundary, including fluvial and tidal-wetland sources. Organic carbon export from the estuaries to the continental shelf was computed by difference, assuming steady state. Uncertainties in the budget were estimated by allowing uncertainties in the supporting model relations. Collectively, U.S. East Coast estuaries are net heterotrophic, with the area-integrated NEP of −1.5 (−2.8, −1.0) Tg C yr−1 (best estimate and 95% confidence interval) and area-normalized NEP of −3.2 (−6.1, −2.3) mol C m−2 yr−1. East Coast estuaries serve as a source of organic carbon to the shelf, exporting 3.4 (2.0, 4.3) Tg C yr−1 or 7.6 (4.4, 9.5) mol C m−2 yr−1. Organic carbon inputs from fluvial and tidal-wetland sources for the region are estimated at 5.4 (4.6, 6.5) Tg C yr−1 or 12 (10, 14) mol C m−2 yr−1 and carbon burial in the open estuarine waters at 0.50 (0.33, 0.78) Tg C yr−1 or 1.1 (0.73, 1.7) mol C m−2 yr−1. Our results highlight the importance of estuarine systems in the overall coastal budget of organic carbon, suggesting that in the aggregate, U.S. East Coast estuaries assimilate (via respiration and burial) ~40% of organic carbon inputs from fluvial and tidal-wetland sources and allow ~60% to be exported to the shelf.

  7. Effect of Carbon Content on the Properties of Iron-Based Powder Metallurgical Parts Produced by the Surface Rolling Process

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    2018-01-01

    Full Text Available In recent years, the rolling densification process has become increasingly widely used to strengthen powder metallurgy parts. The original composition of the rolled powder metallurgy blank has a significant effect on the rolling densification technology. The present work investigated the effects of different carbon contents (0 wt. %, 0.2 wt. %, 0.45 wt. %, and 0.8 wt. % on the rolling densification. The selection of the raw materials in the surface rolling densification process was analyzed based on the pore condition, structure, hardness, and friction performance of the materials. The results show that the 0.8 wt. % carbon content of the surface rolling material can effectively improve the properties of iron-based powder metallurgy parts. The samples with 0.8 wt. % carbon have the highest surface hardness (340 HV0.1 and the lowest surface friction coefficient (0.35. Even if the dense layer depth is 1.13 mm, which is thinner than other samples with low carbon content, it also meets the requirements for powder metallurgy parts such as gears used in the auto industry.

  8. Water quality of the Mississippian carbonate aquifer in parts of middle Tennessee and northern Alabama, 1999

    Science.gov (United States)

    Kingsbury, James A.; Shelton, John M.

    2002-01-01

    Water-quality data for nitrate, fecal-indicator bacteria, pesticides, and volatile organic compounds collected in parts of Middle Tennessee and northern Alabama indicate that the Mississippian carbonate aquifer in these areas is susceptible to contamination from point and nonpoint sources. Thirty randomly located wells (predominantly domestic), two springs, and two additional public-supply wells were sampled in the summer of 1999 as part of the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) Program. These wells and springs were sampled to characterize the occurrence and distribution of the above constituents in this karst aquifer of Mississippian age and to determine the principal environmental factors related to their occurrence.Nitrate and fecal indicator bacteria were frequently detected at the sampled sites. Nitrate exceeded the drinking-water maximum contaminant level of 10 milligrams per liter in two samples; the median concentration for all samples was about 1.5 milligrams per liter. Correlation of nitrate concentrations to the amount of cropland near a site and to pesticide detections indicates that fertilizer application is the predominant source of nitrogen to the aquifer. Fecal-indicator bacteria were present in samples from about 40 percent of the sites. The presence of fecal-indicator bacteria is weakly correlated to the depth to ground water but is not correlated to a specific land use near the sites.Pesticides and pesticide breakdown products (metabolites) were detected at 74 percent of the sites sampled. Concentrations generally were less than 1 microgram per liter and no pesticide detections exceeded drinking-water maximum contaminant levels. The maximum total pesticide concentration measured was about 4 micrograms per liter. Intensity of pesticide use, proximity of sites to areas of pesticide application, and soil hydrologic group were the primary factors affecting the occurrence of pesticides.Volatile organic compounds were

  9. Vulnerability of permafrost carbon to global warming. Part I: model description and role of heat generated by organic matter decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Khvorostyanov, D.V.; Ciais, G. (Laboratoire des Sciences du Climat et l' Environnement, Saclay (France)); Krinner, G. (Laboratoire de Glaciologie et Geophysique de l' Environnement, St Martin d' Heres (France)). e-mail: Dimitry.Khvorostiyanov@lsce.ipsl.fr; Heimann, M. (Max-Planck Inst. of Biogeochemistry, Jena (DE)); Zimov, S.A. (Northeast Science Station, Cherskii (RU))

    2008-07-01

    We constructed a new model to study the sensitivity of permafrost carbon stocks to future climate warming. The one-dimensional model solves an equation for diffusion of heat penetrating from the overlying atmosphere and takes into account additional in situ heat production by active soil microorganisms. Decomposition of frozen soil organic matter and produced CO{sub 2} and methane fluxes result from an interplay of soil heat conduction and phase transitions, respiration, methanogenesis and methanotrophy processes. Respiration and methanotrophy consume soil oxygen and thus can only develop in an aerated top-soil column. In contrast, methanogenesis is not limited by oxygen and can be sustained within the deep soil, releasing sufficient heat to further thaw in depth the frozen carbon-rich soil organic matter. Heat production that accompanies decomposition and methanotrophy can be an essential process providing positive feedback to atmospheric warming through self-sustaining transformation of initially frozen soil carbon into CO{sub 2} and CH{sub 4}. This supplementary heat becomes crucial, however, only under certain climate conditions. Oxygen limitation to soil respiration slows down the process, so that the mean flux of carbon released during the phase of intense decomposition is more than two times less than without oxygen limitation. Taking into account methanogenesis increases the mean carbon flux by 20%. Part II of this study deals with mobilization of frozen carbon stock in transient climate change scenarios with more elaborated methane module, which makes it possible to consider more general cases with various site configurations. Part I (this manuscript) studies mobilization of 400 GtC carbon stock of the Yedoma in response to a stepwise rapid warming focusing on the role of supplementary heat that is released to the soil during decomposition of organic matter

  10. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part I: Micro-structural characterization and geometric modeling

    KAUST Repository

    Han, Fei; Azdoud, Yan; Lubineau, Gilles

    2014-01-01

    A computational strategy to predict the elastic properties of carbon nanotube-reinforced polymer composites is proposed in this two-part paper. In Part I, the micro-structural characteristics of these nano-composites are discerned

  11. Recognition and Binding of a Helix-Loop-Helix Peptide to Carbonic Anhydrase Occurs via Partly Folded Intermediate Structures

    Science.gov (United States)

    Lignell, Martin; Becker, Hans-Christian

    2010-01-01

    Abstract We have studied the association of a helix-loop-helix peptide scaffold carrying a benzenesulfonamide ligand to carbonic anhydrase using steady-state and time-resolved fluorescence spectroscopy. The helix-loop-helix peptide, developed for biosensing applications, is labeled with the fluorescent probe dansyl, which serves as a polarity-sensitive reporter of the binding event. Using maximum entropy analysis of the fluorescence lifetime of dansyl at 1:1 stoichiometry reveals three characteristic fluorescence lifetime groups, interpreted as differently interacting peptide/protein structures. We characterize these peptide/protein complexes as mostly bound but unfolded, bound and partly folded, and strongly bound and folded. Furthermore, analysis of the fluorescence anisotropy decay resulted in three different dansyl rotational correlation times, namely 0.18, 1.2, and 23 ns. Using the amplitudes of these times, we can correlate the lifetime groups with the corresponding fluorescence anisotropy component. The 23-ns rotational correlation time, which appears with the same amplitude as a 17-ns fluorescence lifetime, shows that the dansyl fluorophore follows the rotational diffusion of carbonic anhydrase when it is a part of the folded peptide/protein complex. A partly folded and partly hydrated interfacial structure is manifested in an 8-ns dansyl fluorescence lifetime and a 1.2-ns rotational correlation time. This structure, we believe, is similar to a molten-globule-like interfacial structure, which allows segmental movement and has a higher degree of solvent exposure of dansyl. Indirect excitation of dansyl on the helix-loop-helix peptide through Förster energy transfer from one or several tryptophans in the carbonic anhydrase shows that the helix-loop-helix scaffold binds to a tryptophan-rich domain of the carbonic anhydrase. We conclude that binding of the peptide to carbonic anhydrase involves a transition from a disordered to an ordered structure of the

  12. Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling

    Science.gov (United States)

    Sasai, T.; Murakami, K.; Kato, S.; Matsunaga, T.; Saigusa, N.; Hiraki, K.

    2015-12-01

    Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. However, most studies, which aimed at the estimation of carbon exchanges between ecosystem and atmosphere, remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. In this study, we show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. As methodology for computing the exchanges, we 1) developed a global 1km-grid climate and satellite dataset based on the approach in Setoyama and Sasai (2013); 2) used the satellite-driven biosphere model (Biosphere model integrating Eco-physiological And Mechanistic approaches using Satellite data: BEAMS) (Sasai et al., 2005, 2007, 2011); 3) simulated the carbon exchanges by using the new dataset and BEAMS by the use of a supercomputer that includes 1280 CPU and 320 GPGPU cores (GOSAT RCF of NIES). As a result, we could develop a global uniform system for realistically estimating terrestrial carbon exchange, and evaluate net ecosystem production in each community level; leading to obtain highly detailed understanding of terrestrial carbon exchanges.

  13. Sediment carbon fate in phreatic karst (Part 1): Conceptual model development

    Science.gov (United States)

    Husic, A.; Fox, J.; Agouridis, C.; Currens, J.; Ford, W.; Taylor, C.

    2017-06-01

    Recent research has paid increased attention to quantifying the fate of carbon pools within fluvial networks, but few, if any, studies consider the fate of sediment organic carbon in fluviokarst systems despite that karst landscapes cover 12% of the earth's land surface. The authors develop a conceptual model of sediment carbon fate in karst terrain with specific emphasis upon phreatic karst conduits, i.e., those located below the groundwater table that have the potential to trap surface-derived sediment and turnover carbon. To assist with their conceptual model development, the authors study a phreatic system and apply a mixture of methods traditional and novel to karst studies, including electrical resistivity imaging, well drilling, instantaneous velocimetry, dye tracing, stage recording, discrete and continuous sediment and water quality sampling, and elemental and stable carbon isotope fingerprinting. Results show that the sediment transport carrying capacity of the phreatic karst water is orders of magnitude less than surface streams during storm-activated periods promoting deposition of fine sediments in the phreatic karst. However, the sediment transport carrying capacity is sustained long after the hydrologic event has ended leading to sediment resuspension and prolonged transport. The surficial fine grained laminae occurs in the subsurface karst system; but unlike surface streams, the light-limited conditions of the subsurface karst promotes constant heterotrophy leading to carbon turnover. The coupling of the hydrological processes leads to a conceptual model that frames phreatic karst as a biologically active conveyor of sediment carbon that recharges degraded organic carbon back to surface streams. For example, fluvial sediment is estimated to lose 30% of its organic carbon by mass during a one year temporary residence within the phreatic karst. It is recommended that scientists consider karst pathways when attempting to estimate organic matter stocks

  14. DRUM: a new framework for metabolic modeling under non-balanced growth. Application to the carbon metabolism of unicellular microalgae.

    Science.gov (United States)

    Baroukh, Caroline; Muñoz-Tamayo, Rafael; Steyer, Jean-Philippe; Bernard, Olivier

    2014-01-01

    Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels. In this paper, we propose DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites. DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles. The resulting model describes accurately experimental data obtained in day/night conditions. It efficiently predicts the accumulation and consumption of lipids and carbohydrates.

  15. DRUM: a new framework for metabolic modeling under non-balanced growth. Application to the carbon metabolism of unicellular microalgae.

    Directory of Open Access Journals (Sweden)

    Caroline Baroukh

    Full Text Available Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels. In this paper, we propose DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites. DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles. The resulting model describes accurately experimental data obtained in day/night conditions. It efficiently predicts the accumulation and consumption of lipids and carbohydrates.

  16. Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project - Part 1: calibration, urban enhancements, and uncertainty estimates

    Science.gov (United States)

    Verhulst, Kristal R.; Karion, Anna; Kim, Jooil; Salameh, Peter K.; Keeling, Ralph F.; Newman, Sally; Miller, John; Sloop, Christopher; Pongetti, Thomas; Rao, Preeti; Wong, Clare; Hopkins, Francesca M.; Yadav, Vineet; Weiss, Ray F.; Duren, Riley M.; Miller, Charles E.

    2017-07-01

    We report continuous surface observations of carbon dioxide (CO2) and methane (CH4) from the Los Angeles (LA) Megacity Carbon Project during 2015. We devised a calibration strategy, methods for selection of background air masses, calculation of urban enhancements, and a detailed algorithm for estimating uncertainties in urban-scale CO2 and CH4 measurements. These methods are essential for understanding carbon fluxes from the LA megacity and other complex urban environments globally. We estimate background mole fractions entering LA using observations from four extra-urban sites including two marine sites located south of LA in La Jolla (LJO) and offshore on San Clemente Island (SCI), one continental site located in Victorville (VIC), in the high desert northeast of LA, and one continental/mid-troposphere site located on Mount Wilson (MWO) in the San Gabriel Mountains. We find that a local marine background can be established to within ˜ 1 ppm CO2 and ˜ 10 ppb CH4 using these local measurement sites. Overall, atmospheric carbon dioxide and methane levels are highly variable across Los Angeles. Urban and suburban sites show moderate to large CO2 and CH4 enhancements relative to a marine background estimate. The USC (University of Southern California) site near downtown LA exhibits median hourly enhancements of ˜ 20 ppm CO2 and ˜ 150 ppb CH4 during 2015 as well as ˜ 15 ppm CO2 and ˜ 80 ppb CH4 during mid-afternoon hours (12:00-16:00 LT, local time), which is the typical period of focus for flux inversions. The estimated measurement uncertainty is typically better than 0.1 ppm CO2 and 1 ppb CH4 based on the repeated standard gas measurements from the LA sites during the last 2 years, similar to Andrews et al. (2014). The largest component of the measurement uncertainty is due to the single-point calibration method; however, the uncertainty in the background mole fraction is much larger than the measurement uncertainty. The background uncertainty for the marine

  17. Carbon dioxide stripping in aquaculture -- part II: development of gas transfer models

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The basic mass transfer equation for gases such as oxygen and carbon dioxide can be derived from integration of the driving force equation. Because of the physical characteristics of the gas transfer processes, slightly different models are used for aerators tested under the non steady-state procedures, than for packed columns, or weirs. It is suggested that the standard condition for carbon dioxide should be 20 °C, 1 atm, CCO2=20 mg/kg, and XCO2=0.000285. The selection of the standard condition for carbon dioxide based on a fixed mole fraction ensures that standardized carbon dioxide transfer rates will be comparable even though the value of C*CO2 in the atmosphere is increasing with time. The computation of mass transfer for carbon dioxide is complicated by the impact of water depth and gas phase enrichment on the saturation concentration within the unit, although the importance of either factor depends strongly on the specific type of aerator. For some types of aerators, the most accurate gas phase model remains to be determined for carbon dioxide. The assumption that carbon dioxide can be treated as a non-reactive gas in packed columns may apply for cold acidic waters but not for warm alkaline waters.

  18. Evaluation of refrigerating and air-conditioning technologies in heat cascading systems under the carbon dioxide emissions constraint: the proposal of the energy cascade balance table

    International Nuclear Information System (INIS)

    Shimazaki, Yoichi

    2003-01-01

    The aim of this study was to evaluate the refrigerating and air-conditioning technologies in cases of introducing both heat cascading systems and thermal recycling systems in industries located around urban areas. It is necessary to introduce heat cascading systems in the industrial sector in Japan to reduce carbon dioxide emissions. The concept of heat cascading is the multi-stage use of thermal energy by temperature level. This paper introduces three energy policies for introducing the heat cascading systems. The author develops an energy cascade model based on linear programming so as to minimize the total system costs with carbon taxes. Five cases are investigated. Carbon dioxide emission constraints result in the enhancement of heat cascading, where high temperature heat is supplied for process heating while low temperature heat is shifted to refrigeration. It was found that increasing the amount of garbage combustion waste heat could reduce electric power for the turbo compression refrigerator by promoting waste heat driven ammonia absorption refrigerator. In addition, this study proposes an energy cascade balance table with respect to the temperature level

  19. Coupled Climate-Economy-Biosphere (CoCEB) model - Part 1: Abatement share and investment in low-carbon technologies

    Science.gov (United States)

    Ogutu, K. B. Z.; D'Andrea, F.; Ghil, M.; Nyandwi, C.; Manene, M. M.; Muthama, J. N.

    2015-04-01

    The Coupled Climate-Economy-Biosphere (CoCEB) model described herein takes an integrated assessment approach to simulating global change. By using an endogenous economic growth module with physical and human capital accumulation, this paper considers the sustainability of economic growth, as economic activity intensifies greenhouse gas emissions that in turn cause economic damage due to climate change. Different types of fossil fuels and different technologies produce different volumes of carbon dioxide in combustion. The shares of different fuels and their future evolution are not known. We assume that the dynamics of hydrocarbon-based energy share and their replacement with renewable energy sources in the global energy balance can be modeled into the 21st century by use of logistic functions. Various climate change mitigation policy measures are considered. While many integrated assessment models treat abatement costs merely as an unproductive loss of income, we consider abatement activities also as an investment in overall energy efficiency of the economy and decrease of overall carbon intensity of the energy system. The paper shows that these efforts help to reduce the volume of industrial carbon dioxide emissions, lower temperature deviations, and lead to positive effects in economic growth.

  20. The role of Italian agro-forestry system in controlling the carbon dioxide and methane balance in atmosphere

    International Nuclear Information System (INIS)

    Barbera, G.; La Mantia, T.

    1992-01-01

    After the EEC decision to stabilize the carbon dioxide emissions by year 2000 at the 1990 level, a study has been financed by the Italian Ministry of Environment in order to define what targets could be set by the year 2005 and what strategies could be implemented in Italy in order to achieve consistent carbon dioxide reductions. The results of the research indicate the possibility for Italy to reduce the CO 2 emissions by 25% compared to the 1990 level. In this paper the options to use biomass in order to increase the sink of carbon in Italy are analyzed. The role of forestry, agricultural wastes and residues, urban wastes, energy crops and organic soil matter has been considered. In a climate stabilization scenario, it could be possible to avoid the emissions (or to capture) a yearly quantity of carbon of 18 millions of tons. The potential reduction of methane emissions from the agro-forestry sector on urban wastes disposal is also presented. (author)

  1. Identifying shared and contested elements in climate plans as part of shaping transitions towards a Danish low carbon society

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2011-01-01

    The Danish government's vision about Denmark as a society independent of fossil energy has initiated several Danish energy and climate action plans during 2009-2010 with visions and measures for a 30-40 year time perspective. The paper analyses differences and similarities in action plans from....... The analyses are conducted as part of a project about sustainable transitions towards a low carbon society. The plan from the renewable energy NGO is an energy plan, while the other plans are climate plans, which include non-energy related greenhouse gasses from land use changes and use of fertilizers...... in agriculture. The plans differ with respect to whether and how agricultural production and Danish food consumption should change as part of transitions towards a low carbon society. All four plans agree about a significant increase in Danish wind turbine capacity and stronger energy saving efforts in Danish...

  2. Simulation of the hot flow behaviour of a medium carbon microalloyed steel. Part 2. Dynamic recrystallization: onset and kinetics

    International Nuclear Information System (INIS)

    Cabrera, J.M.; Al Omar, A.; Prado, J.M.

    1997-01-01

    According to the part 1 of this work, in this second part the dynamic recrystallization of a commercial medium carbon microalloyed steel is characterized from the point of view of its onset and kinetics. For this purpose uniaxial hot compression tests were carried out over a range of five orders of magnitude in strain rate and 300 degree centigree of temperature. Experimental results are compared with those reported in the literature and the possible effect of dynamic precipitation is also analyzed. It is verified that the kinetics of dynamics recrystallization can balefully be described by the classical Avrami equation. (Author) 42 refs

  3. Soil organic matter dynamics and CO2 fluxes in relation to landscape scale processes: linking process understanding to regional scale carbon mass-balances

    Science.gov (United States)

    Van Oost, Kristof; Nadeu, Elisabet; Wiaux, François; Wang, Zhengang; Stevens, François; Vanclooster, Marnik; Tran, Anh; Bogaert, Patrick; Doetterl, Sebastian; Lambot, Sébastien; Van wesemael, Bas

    2014-05-01

    In this paper, we synthesize the main outcomes of a collaborative project (2009-2014) initiated at the UCL (Belgium). The main objective of the project was to increase our understanding of soil organic matter dynamics in complex landscapes and use this to improve predictions of regional scale soil carbon balances. In a first phase, the project characterized the emergent spatial variability in soil organic matter storage and key soil properties at the regional scale. Based on the integration of remote sensing, geomorphological and soil analysis techniques, we quantified the temporal and spatial variability of soil carbon stock and pool distribution at the local and regional scales. This work showed a linkage between lateral fluxes of C in relation with sediment transport and the spatial variation in carbon storage at multiple spatial scales. In a second phase, the project focused on characterizing key controlling factors and process interactions at the catena scale. In-situ experiments of soil CO2 respiration showed that the soil carbon response at the catena scale was spatially heterogeneous and was mainly controlled by the catenary variation of soil physical attributes (soil moisture, temperature, C quality). The hillslope scale characterization relied on advanced hydrogeophysical techniques such as GPR (Ground Penetrating Radar), EMI (Electromagnetic induction), ERT (Electrical Resistivity Tomography), and geophysical inversion and data mining tools. Finally, we report on the integration of these insights into a coupled and spatially explicit model and its application. Simulations showed that C stocks and redistribution of mass and energy fluxes are closely coupled, they induce structured spatial and temporal patterns with non negligible attached uncertainties. We discuss the main outcomes of these activities in relation to sink-source behavior and relevance of erosion processes for larger-scale C budgets.

  4. The OSU1/QUA2/TSD2-encoded putative methyltransferase is a critical modulator of carbon and nitrogen nutrient balance response in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Peng Gao

    2008-01-01

    Full Text Available The balance between carbon (C and nitrogen (N nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar 1 mutants (osu1-1, osu1-2 in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N, the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90 and an Asn synthetase isoform (ASN1 are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants.

  5. Carbon balance impacts of land use changes related to the life cycle of Malaysian palm oil-derived biodiesel

    DEFF Research Database (Denmark)

    Hansen, Sune Balle; Olsen, Stig Irving; Ujang, Zaini

    2014-01-01

    to oil palm, in a life cycle perspective.LCA methodology is applied to existing land use change data. The assessment includes the issue of temporary carbon storage in the plantations. Through quantification of emissions from state forest reserve and rubber plantation conversions, the average Malaysian...... palm oil-related land use changes are calculated.The results show that there are high emissions associated with the conversion of Malaysian state forest reserve to oil palm, whereas the conversion of rubber leaves a less significant carbon debt when indirect land use change is not included. Looking...... at the average Malaysian land use changes associated with oil palm shows that land use change emissions are responsible for approximately half of the total conventional biodiesel production emissions. The sensitivity analysis shows that the results could be significantly influenced by data variations in indirect...

  6. Balanced microwave filters

    CERN Document Server

    Hong, Jiasheng; Medina, Francisco; Martiacuten, Ferran

    2018-01-01

    This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 exa...

  7. Carbon Mobilization in Oil Palm Plantation and Milling Based on a Carbon-Balanced Model – A Case Study in Thailand

    OpenAIRE

    Withida Patthanaissaranukool; Chongchin Polprasert

    2011-01-01

    Damage to agricultural areas and household properties occurs more frequently all year round from extreme weather, which is believed to be due to climate change caused by the increase of greenhouse gases – particularly, CO2. In order to help reduce its concentration in the atmosphere, palm oil is a renewable energy which can be used for this purpose. In this study, the carbon mobilization of palm oil was investigated, from oil palm plantation process to the milling process, so as to determine ...

  8. What drives the interannual variations in carbon fluxes and balance in a tropical rainforest of French Guiana?

    Science.gov (United States)

    Aguilos, M. M.; Burban, B.; Wagner, F. H.; Hérault, B.; Bonal, D.

    2016-12-01

    Amazon rainforest - a major contributor to the global carbon sink, is not on steady state and this affects terrestrial carbon pools. Yet, information on the effect of climatic extremes to long-term carbon fluxes is lacking. Thus, using an 11-year eddy covariance data, we examined the carbon fluxes and net carbon uptake in French Guiana's tropical rainforest to determine the interannual and seasonal variations in gross primary production (GPP), ecosystem respiration (RE) and net ecosystem exchange (NEE), so with climatic drivers influencing such changes from 2004 - 2014. GPP varies from 3394.9 g C m‒2 yr‒1 to 4054.5 g C m‒2 yr‒1. RE is more varied than GPP (3057.4 g C m‒2 yr‒1 - 3425.9 g C m‒2 yr‒1. NEE has large interannual variability from ‒68.2 g C m‒2 yr‒1 to ‒596.2 g C m‒2 yr‒1. NEE during wet seasons had higher sink strength than in dry periods. The sudden drop of RE during wet period in 2007 - 2009 may help explain this as it almost doubled the net uptake while GPP had slighter declines. The pattern of NEE appears to be driven by higher rate of increase in RE during dry season with less comparable rise in GPP. This suggests that over 11 years, the ecosystem did not suffer any extreme dry condition strong enough to induce severe decrease in RE. Annually, global radiation (Rg) explains 49% (P<0.0001) for GPP, 42% (P<0.0001) for RE, and 21% (P<0.0001) for NEE. During the wet season, Rg still controls GPP (r2 = 0.45; P <0.0001), RE (r2 = 0.30; P<0.0001;) and NEE (r2 = 0.31; P<0.0001). However, relative extractable water (REW) manifested more strongly during the dry period explaining mainly the variations of GPP (r2 = 0.20; P < 0.0001), RE (r2 = 0.33; P < 0.0001) and NEE (r2 = 0.25; P < 0.0001). Deep rooting system of trees may have caused GPP unsuppressed despite low soil moisture. Therefore, modeling studies must consider incorporating soil water measurements in deeper soils as most tropical trees are dependent on deep soil moisture

  9. Effect of Carbon Nanofiber-Matrix Adhesion on Polymeric Nanocomposite Properties—Part II

    Directory of Open Access Journals (Sweden)

    Khalid Lafdi

    2008-01-01

    carbon nanocomposite. Carbon nanofibers were subjected to electrochemical oxidation in 0.1 M nitric acid for varying times. The strength of adhesion between the nanofiber and an epoxy matrix was characterized by flexural strength and modulus. The surface functional groups formed and their concentration of nanofibers showed a dependence on the degree of oxidation. The addition of chemical functional groups on the nanofiber surface allows them to physically and chemically adhere to the continuous resin matrix. The chemical interaction with the continuous epoxy matrix results in the creation of an interphase region. The ability to chemically and physically interact with the epoxy region is beneficial to the mechanical properties of a carbon nanocomposite. A tailored degree of surface functionalization was found to increase adhesion to the matrix and increase flexural modulus.

  10. The energy balance of Quebec in 1991: Energy consumption decreases for a second consecutive year and the part provided by electricity increases

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    An estimate is presented of the energy balance of Quebec for 1991 (unconventional energy sources excluded), and the definitive energy balance for 1990. The estimates for 1991 are based on sales data for the whole year for electric power, petroleum products, and natural gas, and on the first 9 months of data for coal and coke. In 1990, the energy consumption of Quebec reached 32.2 M TEP (tonnes of equivalent petroleum), or a decrease of 1.8% with respect to 1989. In 1991, it reached 31.1 M TEP, or a decrease of 3.5% with respect to 1990. The electric power consumption in 1991 was 149.1 TWh, an increase of 1.0% with respect to 1990, attributed in part to the economic effects of the recession. The consumption of petroleum products for energy uses attained 93.5 M bbl in 1991, or a drop of 7.3% with respect to 1990. This drop is also attributed to economic reasons. Natural gas sales in 1991 totalled 193.2 billion ft 3 , or a decrease of 2.3% from 1990. In the residential sector, natural gas sales fell 8%, while sales in the industrial and commercial sectors fell 1.6% and 1.3% respectively. Data on energy consumption are given as a function of the energy source (petroleum, coal and coke, natural gas and electric power), as a function of the consuming sector (for electric power and natural gas) or as a function of the nature of the product (for petroleum products). 4 figs., 4 tabs

  11. Quantifying the Carbon Balance of Forest Restoration and Wildfire under Projected Climate in the Fire-Prone Southwestern US.

    Science.gov (United States)

    Hurteau, Matthew D

    2017-01-01

    Climate projections for the southwestern US suggest a warmer, drier future and have the potential to impact forest carbon (C) sequestration and post-fire C recovery. Restoring forest structure and surface fire regimes initially decreases total ecosystem carbon (TEC), but can stabilize the remaining C by moderating wildfire behavior. Previous research has demonstrated that fire maintained forests can store more C over time than fire suppressed forests in the presence of wildfire. However, because the climate future is uncertain, I sought to determine the efficacy of forest management to moderate fire behavior and its effect on forest C dynamics under current and projected climate. I used the LANDIS-II model to simulate carbon dynamics under early (2010-2019), mid (2050-2059), and late (2090-2099) century climate projections for a ponderosa pine (Pinus ponderosa) dominated landscape in northern Arizona. I ran 100-year simulations with two different treatments (control, thin and burn) and a 1 in 50 chance of wildfire occurring. I found that control TEC had a consistent decline throughout the simulation period, regardless of climate. Thin and burn TEC increased following treatment implementation and showed more differentiation than the control in response to climate, with late-century climate having the lowest TEC. Treatment efficacy, as measured by mean fire severity, was not impacted by climate. Fire effects were evident in the cumulative net ecosystem exchange (NEE) for the different treatments. Over the simulation period, 32.8-48.9% of the control landscape was either C neutral or a C source to the atmosphere and greater than 90% of the thin and burn landscape was a moderate C sink. These results suggest that in southwestern ponderosa pine, restoring forest structure and surface fire regimes provides a reasonable hedge against the uncertainty of future climate change for maintaining the forest C sink.

  12. Quantifying the Carbon Balance of Forest Restoration and Wildfire under Projected Climate in the Fire-Prone Southwestern US.

    Directory of Open Access Journals (Sweden)

    Matthew D Hurteau

    Full Text Available Climate projections for the southwestern US suggest a warmer, drier future and have the potential to impact forest carbon (C sequestration and post-fire C recovery. Restoring forest structure and surface fire regimes initially decreases total ecosystem carbon (TEC, but can stabilize the remaining C by moderating wildfire behavior. Previous research has demonstrated that fire maintained forests can store more C over time than fire suppressed forests in the presence of wildfire. However, because the climate future is uncertain, I sought to determine the efficacy of forest management to moderate fire behavior and its effect on forest C dynamics under current and projected climate. I used the LANDIS-II model to simulate carbon dynamics under early (2010-2019, mid (2050-2059, and late (2090-2099 century climate projections for a ponderosa pine (Pinus ponderosa dominated landscape in northern Arizona. I ran 100-year simulations with two different treatments (control, thin and burn and a 1 in 50 chance of wildfire occurring. I found that control TEC had a consistent decline throughout the simulation period, regardless of climate. Thin and burn TEC increased following treatment implementation and showed more differentiation than the control in response to climate, with late-century climate having the lowest TEC. Treatment efficacy, as measured by mean fire severity, was not impacted by climate. Fire effects were evident in the cumulative net ecosystem exchange (NEE for the different treatments. Over the simulation period, 32.8-48.9% of the control landscape was either C neutral or a C source to the atmosphere and greater than 90% of the thin and burn landscape was a moderate C sink. These results suggest that in southwestern ponderosa pine, restoring forest structure and surface fire regimes provides a reasonable hedge against the uncertainty of future climate change for maintaining the forest C sink.

  13. Flexible Carbon-Use Efficiency across Litter Types and during Decomposition Partly Compensates Nutrient Imbalances-Results from Analytical Stoichiometric Models.

    Science.gov (United States)

    Manzoni, Stefano

    2017-01-01

    Mathematical models involving explicit representations of microbial processes have been developed to infer microbial community properties from laboratory and field measurements. While this approach has been used to estimate the kinetic constants related to microbial activity, it has not been fully exploited for inference of stoichiometric traits, such as carbon-use efficiency (CUE). Here, a hierarchy of analytically-solvable mass-balance models of litter carbon (C) and nitrogen (N) dynamics is developed, to infer decomposer CUE from measured C and N contents during litter decomposition. The models are solved in the phase space-expressing litter remaining N as a function of remaining C-rather than in time, thus focusing on the stoichiometric relations during decomposition rather than the kinetics of degradation. This approach leads to explicit formulas that depend on CUE and other microbial properties, which can then be treated as model parameters and retrieved via nonlinear regression. CUE is either assumed time-invariant or as a function of the fraction of remaining litter C as a substitute for time. In all models, CUE tends to increase with increasing litter N availability across a range of litter types. When temporal trends in CUE are considered, CUE increases during decomposition of N-poor litter cohorts, in which decomposers are initially N-limited, but decreases in N-rich litter possibly due to C-limitation. These patterns of flexible CUE that partly compensate stoichiometric imbalances are robust to moderate shifts in decomposer C:N ratio and hold across wide climatic gradients.

  14. Flexible Carbon-Use Efficiency across Litter Types and during Decomposition Partly Compensates Nutrient Imbalances—Results from Analytical Stoichiometric Models

    Science.gov (United States)

    Manzoni, Stefano

    2017-01-01

    Mathematical models involving explicit representations of microbial processes have been developed to infer microbial community properties from laboratory and field measurements. While this approach has been used to estimate the kinetic constants related to microbial activity, it has not been fully exploited for inference of stoichiometric traits, such as carbon-use efficiency (CUE). Here, a hierarchy of analytically-solvable mass-balance models of litter carbon (C) and nitrogen (N) dynamics is developed, to infer decomposer CUE from measured C and N contents during litter decomposition. The models are solved in the phase space—expressing litter remaining N as a function of remaining C—rather than in time, thus focusing on the stoichiometric relations during decomposition rather than the kinetics of degradation. This approach leads to explicit formulas that depend on CUE and other microbial properties, which can then be treated as model parameters and retrieved via nonlinear regression. CUE is either assumed time-invariant or as a function of the fraction of remaining litter C as a substitute for time. In all models, CUE tends to increase with increasing litter N availability across a range of litter types. When temporal trends in CUE are considered, CUE increases during decomposition of N-poor litter cohorts, in which decomposers are initially N-limited, but decreases in N-rich litter possibly due to C-limitation. These patterns of flexible CUE that partly compensate stoichiometric imbalances are robust to moderate shifts in decomposer C:N ratio and hold across wide climatic gradients. PMID:28491054

  15. Flexible Carbon-Use Efficiency across Litter Types and during Decomposition Partly Compensates Nutrient Imbalances—Results from Analytical Stoichiometric Models

    Directory of Open Access Journals (Sweden)

    Stefano Manzoni

    2017-04-01

    Full Text Available Mathematical models involving explicit representations of microbial processes have been developed to infer microbial community properties from laboratory and field measurements. While this approach has been used to estimate the kinetic constants related to microbial activity, it has not been fully exploited for inference of stoichiometric traits, such as carbon-use efficiency (CUE. Here, a hierarchy of analytically-solvable mass-balance models of litter carbon (C and nitrogen (N dynamics is developed, to infer decomposer CUE from measured C and N contents during litter decomposition. The models are solved in the phase space—expressing litter remaining N as a function of remaining C—rather than in time, thus focusing on the stoichiometric relations during decomposition rather than the kinetics of degradation. This approach leads to explicit formulas that depend on CUE and other microbial properties, which can then be treated as model parameters and retrieved via nonlinear regression. CUE is either assumed time-invariant or as a function of the fraction of remaining litter C as a substitute for time. In all models, CUE tends to increase with increasing litter N availability across a range of litter types. When temporal trends in CUE are considered, CUE increases during decomposition of N-poor litter cohorts, in which decomposers are initially N-limited, but decreases in N-rich litter possibly due to C-limitation. These patterns of flexible CUE that partly compensate stoichiometric imbalances are robust to moderate shifts in decomposer C:N ratio and hold across wide climatic gradients.

  16. Improved constraints on in situ rates and on quantification of complete chloroethene degradation from stable carbon isotope mass balances in groundwater plumes

    Science.gov (United States)

    Höhener, Patrick; Elsner, Martin; Eisenmann, Heinrich; Atteia, Olivier

    2015-11-01

    Spills of chloroethenes (CEs) at industrial and urban sites can create groundwater plumes in which tetrachloro- and trichloroethene sequentially degrade to dichloroethenes, vinyl chloride (VC) and ethene, or ethane under reducing conditions. For detoxification, degradation must go beyond VC. Assessments based on ethene and ethane, however, are difficult because these products are volatile, may stem from alternative sources, can be further transformed and are not always monitored. To alternatively quantify degradation beyond VC, stable carbon isotope mass balances have been proposed where concentration-weighted CE isotope ratios are summed up and compared to the original source isotope ratio. Reported assessments, however, have provided not satisfactorily quantified results entailing greatly differing upper and lower estimates. This work proposes an integrative approach to better constrain the extent of total chloroethene degradation in groundwater samples. It is based on fitting of measured concentration and compound-specific stable carbon isotope data to an analytical reactive transport equation simulating steady-state plumes in two dimensions using an EXCEL spreadsheet. The fitting also yields estimates of degradation rates, of source width and of dispersivities. The approach is validated using two synthetic benchmark cases where the true extent of degradation is well known, and using data from two real field cases from literature.

  17. Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

    Directory of Open Access Journals (Sweden)

    M. Hallenberger

    2018-01-01

    Full Text Available The Zechstein-2-Carbonates represent one of the most prolific hydrocarbon systems of Central Europe. Carbonate reservoir quality is primarily controlled by mineralogy, with dolomite representing moderate-to-good porosities and calcite commonly representing low porosities. Current models suggest that this calcite is the result of a basin-wide phase of dedolomitization. The calcium (Ca source for the dedolomites is thought to be derived from the fluids liberated during gypsum-to-anhydrite conversion. We present an easy-to-use and generally applicable template to estimate the dedolomitization potential of these fluids. Depending on reaction stoichiometry, salinity, and temperature, we estimate that between 2.8⁎10−3 m3 and 6.2⁎10−3 m3 of calcite may replace dolomite for each m3 of anhydrite created. Within the constraints dictated by the environment of the late Permian Zechstein basin, we estimate that about 5⁎10−3 m3 of dedolomite is created for each m3 of anhydrite. Mass balance constraints indicate that fluids derived from gypsum-to-anhydrite conversion account for less than 1% of the observed dedolomite in most of the studied industry wells from northern Germany.

  18. Balance Problems

    Science.gov (United States)

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady. You may ... related injuries, such as a hip fracture. Some balance problems are due to problems in the inner ...

  19. CARBON-FIBRE-REINFORCED POLYMER PARTS EFFECT ON SPACECRAFT OPTOELECTRONIC MODULE LENS SCATTERING

    Directory of Open Access Journals (Sweden)

    S. S. Kolasha

    2016-01-01

    Full Text Available Spacecraft optoelectronic modules traditionally have aluminum alloy or titanium alloy casing which substantial weight increases fuel consumption required to put them into orbit and, consequently, total cost of the project. Carbon fiber reinforced polymer based composite constructive materials is an efficient solution that allows reducing weight and dimensions of large optoelectronic modules 1,5–3 times and the coefficient of linear thermal expansion 15–20 times if compared with metals. Optical characteristic is a crucial feature of carbon-fibre-reinforced polymer that determines composite material interaction with electromagnetic emission within the optical range. This work was intended to develop a method to evaluate Carbon fiber reinforced polymer optoelectronic modules casing effect on lens scattering by computer simulation with Zemax application software package. Degrees of scattered, reflected and absorbed radiant flux effect on imaging quality are described here. The work included experimental study in order to determine bidirectional reflectance distribution function by goniometric method for LUP-0.1 carbon fabric check test pieces of EDT-69U epoxy binder with EPOFLEX-0.4 glue layer and 5056-3.5-23-A aluminium honeycomb filler. The scattered emission was registered within a hemisphere above the check test piece surface. Optical detection direction was determined with zenith (0º < θ < 90º and azimuth (0º < φ < 180º angles with 10° increment. The check test piece surface was proved to scatter emission within a narrow angle range (approximately 20° with clear directivity. Carbon fiber reinforced polymers was found to feature integrated reflectance coefficient 3 to 4 times greater than special coatings do. 

  20. Annual Forest Monitoring as part of Indonesia's National Carbon Accounting System

    Science.gov (United States)

    Kustiyo, K.; Roswintiarti, O.; Tjahjaningsih, A.; Dewanti, R.; Furby, S.; Wallace, J.

    2015-04-01

    Land use and forest change, in particular deforestation, have contributed the largest proportion of Indonesia's estimated greenhouse gas emissions. Indonesia's remaining forests store globally significant carbon stocks, as well as biodiversity values. In 2010, the Government of Indonesia entered into a REDD+ partnership. A spatially detailed monitoring and reporting system for forest change which is national and operating in Indonesia is required for participation in such programs, as well as for national policy reasons including Monitoring, Reporting, and Verification (MRV), carbon accounting, and land-use and policy information. Indonesia's National Carbon Accounting System (INCAS) has been designed to meet national and international policy requirements. The INCAS remote sensing program is producing spatially-detailed annual wall-to-wall monitoring of forest cover changes from time-series Landsat imagery for the whole of Indonesia from 2000 to the present day. Work on the program commenced in 2009, under the Indonesia-Australia Forest Carbon Partnership. A principal objective was to build an operational system in Indonesia through transfer of knowledge and experience, from Australia's National Carbon Accounting System, and adaptation of this experience to Indonesia's requirements and conditions. A semi-automated system of image pre-processing (ortho-rectification, calibration, cloud masking and mosaicing) and forest extent and change mapping (supervised classification of a 'base' year, semi-automated single-year classifications and classification within a multi-temporal probabilistic framework) was developed for Landsat 5 TM and Landsat 7 ETM+. Particular attention is paid to the accuracy of each step in the processing. With the advent of Landsat 8 data and parallel development of processing capability, capacity and international collaborations within the LAPAN Data Centre this processing is being increasingly automated. Research is continuing into improved

  1. Multi-year study of the carbonate system in the Chukchi Sea with emphasizes on its western part

    Science.gov (United States)

    Semiletov, I. P.; Pipko, I.; Pugach, S.

    2015-12-01

    Variability of the Arctic climate has affected many aspects of the Arctic environment, especially in the Pacific sector of the Arctic. The primary implication is that today's Arctic cryosphere (glaciers, frozen ground, and sea ice) and biosphere (terrestrial, lacustrine, and marine) are not at steady state; they have changed and will continue to change in response to evolving Arctic climate. Over the decade 2004-2013 environmental changes in the Pacific sector of the Arctic have been dramatic enough to suggest that a 'new normal' climate is emerging (Wood et al., 2015). Like everywhere in the Arctic, understanding of environmental change in the Chukchi Sea is hindered by sparse data. Dynamics of the carbonate system (CS) in the eastern Chukchi Sea (US EEZ) has been studied more extensively for a longer period and is better understood than in its western (Russian EEZ) part. Here we focus on the carbonate system data collected in the Russian part of the Chukchi Sea over > 10 years (2000-2011). Our data exhibit a strong mesoscale and interannual dynamics of carbonate system parameters in the surface seawater. The aragonite saturation state (WAr) was highly variable but also has generally been decreasing in the upper waters from 2000 to 2011. It was shown that despite strong sea ice loss, waters heating and storm increasing, the surface waters in this area have been consistently undersaturated by CO2 with respect to the atmosphere. Notable localized exceptions, where CO2 outgassing occurs, include the well-mixed waters near Bering Strait. Combining our long-term carbonate system data set (1996-2011) with the available literature data we felt in conclusion that the entire Chukchi Sea during ice-free season absorbs ~12-15× 1012 g C and a significant part of this carbon was transferred to the deep layers and insulated from contact with the atmosphere for a long time. Note that the CO2 invasion is a similar value with the CO2 outgassing from the shallow eastern Laptev Sea

  2. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    Science.gov (United States)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  3. Water, Energy and Carbon Balance Research: Recovery Trajectories For Oil Sands Reclamation and Disturbed Watersheds in the Western Boreal Forest

    Science.gov (United States)

    Petrone, R. M.; Carey, S. K.

    2014-12-01

    The Oil Sand Region (OSR) of North-Central Alberta exists within the sub-humid Boreal Plains (BP) ecozone, with a slight long-term moisture deficit regime. Despite this deficit, the BP is comprised of productive wetland and mixed wood (aspen and conifer dominated) forests. Reclamation activities are now underway at a large number of surface mining operations in the OSR, where target ecosystems are identified, soil prescriptions placed and commercial forest species planted. Some watersheds have been created that now contain wetlands. However, recent work in the BP suggests that over time wetlands supply moisture for the productivity of upland forests. Thus, water use of reclaimed forests is going to be critical in determining the sustainability of these systems and adjacent wetlands, and whether in time, either will achieve some form of equivalent capability that will allow for certification by regulators. A critical component in the success of any reclamation is that sufficient water is available to support target ecosystems through the course of natural climate cycles in the region. Water Use Efficiency (WUE), which links photosynthesis (GEP) with water use (Evapotranspiration (ET)), provides a useful metric to compare ecosystems and evaluate their utilization of resources. In this study, 41 site years of total growing season water and carbon flux data over 8 sites (4 reclamation, 4 regeneration) were evaluated using eddy covariance micrometeorological towers. WUE shows clear discrimination among ecosystem types as aspen stands assimilate more carbon per unit weight of water than conifers. WUEs also change with time as ecosystems become more effective at transpiring water through plant pathways compared with bare-soil evaporation, which allows an assessment of ability to limit water loss without carbon uptake. In addition, clonal rooting systems allow aspen forests to recover quicker after disturbance than reclamation sites in terms of their WUE. For reclamation

  4. Potential of forest management to reduce French carbon emissions - regional modelling of the French forest carbon balance from the forest to the wood.

    Science.gov (United States)

    Valade, A.; Luyssaert, S.; Bellassen, V.; Vallet, P.

    2015-12-01

    In France the low levels of forest harvest (40 Mm3 per year over a volume increment of 89Mm3) is frequently cited to push for a more intensive management of the forest that would help reducing CO2 emissions. This reasoning overlooks the medium-to-long-term effects on the carbon uptake at the national scale that result from changes in the forest's structure and delayed emissions from products decay and bioenergy burning, both determinant for the overall C fluxes between the biosphere and the atmosphere. To address the impacts of an increase in harvest removal on biosphere-atmosphere carbon fluxes at national scale, we build a consistent regional modeling framework to integrate the forest-carbon system from photosynthesis to wood uses. We aim at bridging the gap between regional ecosystem modeling and land managers' considerations, to assess the synergistic and antagonistic effects of management strategies over C-based forest services: C-sequestration, energy and material provision, fossil fuel substitution. For this, we built on inventory data to develop a spatial forest growth simulator and design a novel method for diagnosing the current level of management based on stand characteristics (density, quadratic mean diameter or exploitability). The growth and harvest simulated are then processed with a life cycle analysis to account for wood transformation and uses. Three scenarii describe increases in biomass removals either driven by energy production target (set based on national prospective with a lock on minimum harvest diameters) or by changes in management practices (shorter or longer rotations, management of currently unmanaged forests) to be compared with business as usual simulations. Our management levels' diagnostics quantifies undermanagement at national scale and evidences the large weight of ownership-based undermanagement with an average of 26% of the national forest (between 10% and 40% per species) and thus represents a huge potential wood resource

  5. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part II: Mechanical modeling

    KAUST Repository

    Han, Fei

    2014-01-01

    We present two modeling approaches for predicting the macroscopic elastic properties of carbon nanotubes/polymer composites with thick interphase regions at the nanotube/matrix frontier. The first model is based on local continuum mechanics; the second one is based on hybrid local/non-local continuum mechanics. The key computational issues, including the peculiar homogenization technique and treatment of periodical boundary conditions in the non-local continuum model, are clarified. Both models are implemented through a three-dimensional geometric representation of the carbon nanotubes network, which has been detailed in Part I. Numerical results are shown and compared for both models in order to test convergence and sensitivity toward input parameters. It is found that both approaches provide similar results in terms of homogenized quantities but locally can lead to very different microscopic fields. © 2013 Elsevier B.V. All rights reserved.

  6. Modelling Behaviour of a Carbon Epoxy Composite Exposed to Fire: Part I—Characterisation of Thermophysical Properties

    Directory of Open Access Journals (Sweden)

    Pauline Tranchard

    2017-05-01

    Full Text Available Thermophysical properties of a carbon-reinforced epoxy composite laminate (T700/M21 composite for aircraft structures were evaluated using different innovative characterisation methods. Thermogravimetric Analysis (TGA, Simultaneous Thermal analysis (STA, Laser Flash analysis (LFA, and Fourier Transform Infrared (FTIR analysis were used for measuring the thermal decomposition, the specific heat capacity, the anisotropic thermal conductivity of the composite, the heats of decomposition and the specific heat capacity of released gases. It permits to get input data to feed a three-dimensional (3D model given the temperature profile and the mass loss obtained during well-defined fire scenarios (model presented in Part II of this paper. The measurements were optimised to get accurate data. The data also permit to create a public database on an aeronautical carbon fibre/epoxy composite for fire safety engineering.

  7. Modelling Behaviour of a Carbon Epoxy Composite Exposed to Fire: Part I-Characterisation of Thermophysical Properties.

    Science.gov (United States)

    Tranchard, Pauline; Samyn, Fabienne; Duquesne, Sophie; Estèbe, Bruno; Bourbigot, Serge

    2017-05-04

    Thermophysical properties of a carbon-reinforced epoxy composite laminate (T700/M21 composite for aircraft structures) were evaluated using different innovative characterisation methods. Thermogravimetric Analysis (TGA), Simultaneous Thermal analysis (STA), Laser Flash analysis (LFA), and Fourier Transform Infrared (FTIR) analysis were used for measuring the thermal decomposition, the specific heat capacity, the anisotropic thermal conductivity of the composite, the heats of decomposition and the specific heat capacity of released gases. It permits to get input data to feed a three-dimensional (3D) model given the temperature profile and the mass loss obtained during well-defined fire scenarios (model presented in Part II of this paper). The measurements were optimised to get accurate data. The data also permit to create a public database on an aeronautical carbon fibre/epoxy composite for fire safety engineering.

  8. Modelling Behaviour of a Carbon Epoxy Composite Exposed to Fire: Part I—Characterisation of Thermophysical Properties

    Science.gov (United States)

    Tranchard, Pauline; Samyn, Fabienne; Duquesne, Sophie; Estèbe, Bruno; Bourbigot, Serge

    2017-01-01

    Thermophysical properties of a carbon-reinforced epoxy composite laminate (T700/M21 composite for aircraft structures) were evaluated using different innovative characterisation methods. Thermogravimetric Analysis (TGA), Simultaneous Thermal analysis (STA), Laser Flash analysis (LFA), and Fourier Transform Infrared (FTIR) analysis were used for measuring the thermal decomposition, the specific heat capacity, the anisotropic thermal conductivity of the composite, the heats of decomposition and the specific heat capacity of released gases. It permits to get input data to feed a three-dimensional (3D) model given the temperature profile and the mass loss obtained during well-defined fire scenarios (model presented in Part II of this paper). The measurements were optimised to get accurate data. The data also permit to create a public database on an aeronautical carbon fibre/epoxy composite for fire safety engineering. PMID:28772854

  9. Balance of ionization and recombination of carbon ions in high density peripheral plasmas of the JT-60 U tokamak

    International Nuclear Information System (INIS)

    Nakano, T.; Kubo, H.; Asakura, N.; Shimizu, K.

    2009-01-01

    In high density and low temperature peripheral plasmas of JT-60 U, i.e. detached divertor plasmas, C III and C IV lines were observed by a visible and VUV spectrometers in order to investigate dominant radiators, radiation power and particle balance between the radiators. An emission peak was found between the inner strike and the X-point. With increasing electron density, the emission peak moved to the X-point with a constant electron temperature of ∼7 eV. In the case the emission peak was located on the X-point, the dominant radiators in the emission peak were C 2+ and C 3+ , which contributed 30% and 60% to the total radiative power. It was found that C 3+ was produced by the ionization of C 2+ and the volume recombination of C 4+ at a similar rates. However, the loss flux of C 3+ was lower by two orders of magnitude than the C 3+ production flux, indicating that another loss mechanism such as transport loss around the X-point was significant.

  10. Integration of hydrothermal carbonization and a CHP plant: Part 2 –operational and economic analysis

    International Nuclear Information System (INIS)

    Saari, Jussi; Sermyagina, Ekaterina; Kaikko, Juha; Vakkilainen, Esa; Sergeev, Vitaly

    2016-01-01

    Wood-fired combined heat and power (CHP) plants are a proven technology for producing domestic, carbon-neutral heat and power in Nordic countries. One drawback of CHP plants is the low capacity factors due to varying heat loads. In the current economic environment, uncertainty over energy prices creates also uncertainty over investment profitability. Hydrothermal carbonization (HTC) is a promising thermochemical conversion technology for producing an improved, more versatile wood-based fuel. Integrating HTC with a CHP plant allows simplifying the HTC process and extending the CHP plant operating time. An integrated polygeneration plant producing three energy products is also less sensitive to price changes in any one product. This study compares three integration cases chosen from the previous paper, and the case of separate stand-alone plants. The best economic performance is obtained using pressurized hot water from the CHP plant boiler drum as HTC process water. This has the poorest efficiency, but allows the greatest cost reduction in the HTC process and longest CHP plant operating time. The result demonstrates the suitability of CHP plants for integration with a HTC process, and the importance of economic and operational analysis considering annual load variations in sufficient detail. - Highlights: • Integration of wood hydrothermal carbonization with a small CHP plant studied. • Operation and economics of three concepts and stand-alone plants are compared. • Sensitivity analysis is performed. • Results show technical and thermodynamic analysis inadequate and misleading alone. • Minimizing HTC investment, extending CHP operating time important for profitability.

  11. Adapting fire management to future fire regimes: impacts on boreal forest composition and carbon balance in Canadian National Parks

    Science.gov (United States)

    de Groot, W. J.; Flannigan, M. D.; Cantin, A.

    2009-04-01

    The effects of future fire regimes altered by climate change, and fire management in adaptation to climate change were studied in the boreal forest region of western Canada. Present (1975-90) and future (2080-2100) fire regimes were simulated for several National Parks using data from the Canadian (CGCM1) and Hadley (HadCM3) Global Climate Models (GCM) in separate simulation scenarios. The long-term effects of the different fire regimes on forests were simulated using a stand-level, boreal fire effects model (BORFIRE). Changes in forest composition and biomass storage due to future altered fire regimes were determined by comparing current and future simulation results. This was used to assess the ecological impact of altered fire regimes on boreal forests, and the future role of these forests as carbon sinks or sources. Additional future simulations were run using adapted fire management strategies, including increased fire suppression and the use of prescribed fire to meet fire cycle objectives. Future forest composition, carbon storage and emissions under current and adapted fire management strategies were also compared to determine the impact of various future fire management options. Both of the GCM's showed more severe burning conditions under future fire regimes. This includes fires with higher intensity, greater depth of burn, greater total fuel consumption and shorter fire cycles (or higher rates of annual area burned). The Canadian GCM indicated burning conditions more severe than the Hadley GCM. Shorter fire cycles of future fire regimes generally favoured aspen, birch, and jack pine because it provided more frequent regeneration opportunity for these pioneer species. Black spruce was only minimally influenced by future fire regimes, although white spruce declined sharply. Maintaining representation of pure and mixed white spruce ecosystems in natural areas will be a concern under future fire regimes. Active fire suppression is required in these areas. In

  12. Chemistry of sustainability-Part I: Carbon dioxide as an organic synthon and Part II: Study of thermodynamics of cation exchange reactions in semiconductor nanocrystals

    Science.gov (United States)

    Sathe, Ajay A.

    Sustainability is an important part of the design and development of new chemical and energy conversion processes. Simply put sustainability is the ability to meet our needs without sacrificing the ability of the next generations to meet theirs. This thesis describes our efforts in developing two orthogonal strategies for the fixation of CO2 by utilizing high energy intermediates which are generated via oxidative or reductive processes on common organic substrates and of thermochemical measurements of cation exchange reactions which will aid the development of new materials relevant for energy conversion and storage. The first chapter lays a background for the challenges and opportunities for the use of CO2 in organic synthesis. The rapidly growing field of continuous flow processing in organic synthesis is introduced, and its importance in the development of sustainable chemical conversions is highlighted. The second chapter describes the development of a novel route to alpha-amino acids via reductive carboxylation of imines. A mechanistic proposal is presented and the reaction is shown to proceed through the intermediacy of alpha-amino alkyl metal species. Possible strategies for designing catalytic and enantioselective variants of the reaction are presented. The third chapter describes the development of a catalytic oxidative carboxylation of olefins to yield cyclic carbonates. The importance of flow chemistry and membrane separation is demonstrated by allowing the combination of mutually incompatible reagents in a single reaction sequence. While the use of carbon dioxide for synthesis of organic fine chemicals is not expected to help reduce the atmospheric carbon dioxide levels, or tackle climate change, it certainly has the potential to reduce our dependence on non-sustainable carbon feedstocks, and help achieve a carbon neutral chemical life cycle. Having described the use of carbon dioxide and flow chemistry for sustainable chemical conversion, the fourth

  13. Balance Problems

    Science.gov (United States)

    ... fully trust your sense of balance. Loss of balance also raises the risk of falls. This is a serious and even life-threatening ... 65. Balance disorders are serious because of the risk of falls. But occasionally balance problems may warn of another health condition, such ...

  14. Carbon balance in bioregenerative life support systems: Some effects of system closure, waste management, and crop harvest index

    Science.gov (United States)

    Wheeler, Raymond M.

    In Advanced Life Support (ALS) systems with bioregenerative components, plant photosynthesis would be used to produce O2 and food, while removing CO2. Much of the plant biomass would be inedible and hence must be considered in waste management. This waste could be oxidized (e.g., incinerated or aerobically digested) to resupply CO2 to the plants, but this would not be needed unless the system were highly closed with regard to food. For example, in a partially closed system where some of the food is grown and some is imported, CO2 from oxidized waste when combined with crew and microbial respiration could exceed the CO2 removal capability of the plants. Moreover, it would consume some O2 produced from photosynthesis that could have been used by the crew. For partially closed systems it would be more appropriate to store or find other uses for the inedible biomass and excess carbon, such as generating soils or growing woody plants (e.g., dwarf fruit trees). Regardless of system closure, high harvest crops (i.e., crops with a high edible to total biomass ratio) would increase food production per unit area and O2 yields for systems where waste biomass is oxidized to recycle CO2. Such interlinking effects between the plants and waste treatment strategies point out the importance of oxidizing only that amount of waste needed to optimize system performance.

  15. Analysis of Metabolites and Carbon Balance in the Biofilteration of Cumene Using Loofa Sponge as Biofilter Media.

    Science.gov (United States)

    Shahi, Amrita; Rai, B N; Singh, R S

    2016-09-01

    A laboratory-scale biofilter study was performed to treat cumene-inoculated mixed culture of bacterial community and loofa sponge (Luffa cylindrica) as support media for a period of 120 days in five distinct phases. The removal efficiency was obtained in the range of 40-85 % with maximum elimination capacity of 700 g m(-3) h(-1) at the inlet load of 1167 g m(-3) h(-1). The result demonstrated that loofa sponge is good support media for the removal of cumene at higher loading rates. Loofa sponge was characterized via chemical analysis and analytical techniques such as XRD; FTIR; XPS; and CHN, and the result obtained confirms its suitability as biofilter media. The SEM results of loofa with inoculum shows the formation of a biofilm layer on the surface of loofa. The GC-MS analysis of leachate confirms the presence of different organic compounds such as acetaldehyde and 4-hydroxy-2-oxopentanoic acids which are stable metabolites during cumene biodegradation. About 12.69 % of carbon present in inlet cumene was converted to biomass.

  16. A multi-tiered approach for assessing the forestry and wood products industries' impact on the carbon balance.

    Science.gov (United States)

    Knauf, Marcus

    2015-12-01

    The forestry and wood products industries play a significant role in CO 2 emissions reduction by increasing carbon stocks in living forest biomass and wood products. Moreover, wood can substitute for fossil fuels. Different methods can be used to assess the impact of regional forestry and wood products industries on regional CO 2 emissions. This article considers three of those methods and combines them into a multi-tiered approach. The multi-tiered approach proposed in this article combines: 1) a Kyoto-Protocol-oriented method focused on changes in CO 2 emissions resulting from regional industrial production, 2) a consumer-oriented method focused on changes in CO 2 emissions resulting from regional consumption, and 3) a value-creation-oriented method focused on changes in CO 2 emissions resulting from forest management and wood usage strategies. North Rhine-Westphalia is both a typical German state and an example of a region where each of these three methods yields different results. It serves as a test case with which to illustrate the advantages of the proposed approach. This case study argues that the choice of assessment methods is essential when developing and evaluating a strategy for reducing CO 2 emissions. Emissions can be reduced through various social and economic processes. Since none of the assessment methods considered above is suitable for all of these processes, only a multi-tiered approach may ensure that strategy development results in an optimal emissions reduction strategy.

  17. Behavior of porous beryllium under thermomechanical loading. Part 7. Calibration studies on the carbon piezoresistive gage

    International Nuclear Information System (INIS)

    Horning, R.R.; Isbell, W.M.

    1975-01-01

    The calibrations, time responses, and Hugoniot for carbon piezoresistive gages from two manufacturers are presented. These gages exhibit a high sensitivity of about --20 percent resistance change per GPa at 0.5 GPa. Their equilibrium times, when tested in fused silica, exceed 0.6 μs below 0.5 GPa but improve at higher stresses and under better impedance matching conditions. They can be made of low atomic number materials, making them interesting candidates for studying the mechanical responses of materials to electron and x-ray deposition. (U.S.)

  18. Carbon and water vapore balance in a primary subtropical evergreen forest in Southewest China under a changing climate

    Science.gov (United States)

    Song, Q. H.; Zhang, Y. P.

    2017-12-01

    The Ailaoshan Nature Reserve in Yunnan province, southwestern China hosts about 5000 ha of primary subtropical evergreen mountain cloud forest. A widespread and severe drought occurred in southwestern China in 2009 and 2010, providing a unique opportunity to directly evaluate how water use efficiency (WUE) changes with drought stress in the primary subtropical forest. We calculated WUE using measures of gross primary production (GPP) and evapotranspiration (ET) from five years of continuous eddy covariance measurements (2009-2013) obtained over a primary subtropical evergreen broadleaved forest in southwestern China. Annual mean WUE exhibited a decreasing trend from 2009 to 2013, varying from 2.28 to 2.68 g C kg H2O-1. The multiyear average WUE was 2.48 ± 0.17 (mean ± standard deviation) g C kg H2O-1. WUE increased greatly in the driest year (2009), due to a larger decline in ET than in GPP. Unfortunately, the same study site experienced a particularly extreme climate anomaly during January 2015, with a heavy snow of up to 50 cm in depth, which led to severe forest damage. The forest canopy was severely damaged by the heavy snow, and the leaf area index (LAI) decreased significantly from January to July 2015. GPP, net ecosystem exchange (NEE), and Ecosystem respiration (Reco) all sharply decreased in 2015 after the heavy snow. On average, a strong decrease of 544 g C m-2 year-1 in annual NEE in 2015 was associated with a decrease of 829 g C m-2 year-1 in annual GPP and a decrease of 285 g C m-2 year-1 in annual Reco. Overall, annual net C uptake in 2015 was reduced by 76% compared to the mean C uptake of the previous four years. A sharp increase in carbon uptake was also observed in 2016, indicating that long-term, continuous measurements should be carried out to evaluate the overall response to the disturbance.

  19. Carbon balance and crop residue management in dynamic equilibrium under a no-till system in Campos Gerais

    Directory of Open Access Journals (Sweden)

    Ademir de Oliveira Ferreira

    2012-11-01

    Full Text Available The adoption of no-tillage systems (NT and the maintenance of crop residues on the soil surface result in the long-term increase of carbon (C in the system, promoting C sequestration and reducing C-CO2 emissions to the atmosphere. The purpose of this study was to evaluate the C sequestration rate and the minimum amount of crop residues required to maintain the dynamic C equilibrium (dC/dt = 0 of two soils (Typic Hapludox with different textural classes. The experiment was arranged in a 2 x 2 x 2 randomized block factorial design. The following factors were analyzed: (a two soil types: Typic Hapludox (Oxisol with medium texture (LVTM and Oxisol with clay texture (LVTA, (b two sampling layers (0-5 and 5-20 cm, and (c two sampling periods (P1 - October 2007; P2 - September 2008. Samples were collected from fields under a long-term (20 years NT system with the following crop rotations: wheat/soybean/black oat + vetch/maize (LVTM and wheat/maize/black oat + vetch/soybean (LVTA. The annual C sequestration rates were 0.83 and 0.76 Mg ha-1 for LVTM and LVTA, respectively. The estimates of the minimum amount of crop residues required to maintain a dynamic equilibrium (dC/dt = 0 were 7.13 and 6.53 Mg ha-1 year-1 for LVTM and LVTA, respectively. The C conversion rate in both studied soils was lower than that reported in other studies in the region, resulting in a greater amount of crop residues left on the soil surface.

  20. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity.

    Science.gov (United States)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D; Jones, Edward O; Hatano, Ryusuke

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959-2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from -1.26MgCha(-1)yr(-1) in 1959-0.26 Mg Cha(-1)yr(-1) in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959-2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Carbon nanotubes part I: preparation of a novel and versatile drug-delivery vehicle

    Science.gov (United States)

    Karimi, Mahdi; Solati, Navid; Amiri, Mohammad; Mirshekari, Hamed; Mohamed, Elmira; Taheri, Mahdiar; Hashemkhani, Mahshid; Saeidi, Ahad; Estiar, Mehrdad Asghari; Kiani, Parnian; Ghasemi, Amir; Basri, Seyed Masoud Moosavi; Aref, Amir R

    2015-01-01

    Introduction It is 23 years since carbon allotrope known as carbon nanotubes (CNT) was discovered by Iijima, who described them as “rolled graphite sheets inserted into each other”. Since then, CNTs have been studied in nanoelectronic devices. However, CNTs also possess the versatility to act as drug- and gene-delivery vehicles. Areas covered This review covers the synthesis, purification and functionalization of CNTs. Arc discharge, laser ablation and chemical vapor deposition are the principle synthesis methods. Non-covalent functionalization relies on attachment of biomolecules by coating the CNT with surfactants, synthetic polymers and biopolymers. Covalent functionalization often involves the initial introduction of carboxylic acids or amine groups, diazonium addition, 1,3-dipolar cycloaddition or reductive alkylation. The aim is to produce functional groups to attach the active cargo. Expert opinion In this review, the feasibility of CNT being used as a drug-delivery vehicle is explored. The molecular composition of CNT is extremely hydrophobic and highly aggregation-prone. Therefore, most of the efforts towards drug delivery has centered on chemical functionalization, which is usually divided in two categories; non-covalent and covalent. The biomedical applications of CNT are growing apace, and new drug-delivery technologies play a major role in these efforts. PMID:25601356

  2. Development of carbon fiber staves for the strip part of the PANDA micro vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Quagli, Tommaso; Brinkmann, Kai-Thomas [II. Physikalisches Institut, Justus-Liebig Universitaet Giessen (Germany); Fracassi, Vincenzo; Grunwald, Dirk; Rosenthal, Eberhard [ZEA-1, Forschungszentrum Juelich GmbH, Juelich (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    PANDA is a key experiment of the future FAIR facility, under construction in Darmstadt, Germany. It will study the collisions between an antiproton beam and a fixed proton or nuclear target. The Micro Vertex Detector (MVD) is the innermost detector of the apparatus and is composed of four concentric barrels and six forward disks, instrumented with silicon hybrid pixel detectors and double-sided silicon microstrip detectors; its main task is the identification of primary and secondary vertices. The central requirements include high spatial and time resolution, trigger-less readout with high rate capability, good radiation tolerance and low material budget. Because of the compact layout of the system, its integration poses significant challenges. The detectors in the strip barrels will be supported by a composite structure of carbon fiber and carbon foam; a water-based cooling system embedded in the mechanical supports will be used to remove the excess heat from the readout electronics. In this contribution the design of the barrel stave and the ongoing development of some hardware components related to its integration will be presented.

  3. The forgotten part of carbon cycling: Organic matter storage and turnover in subsoils [SUBSOM

    Science.gov (United States)

    Marschner, B.

    2013-12-01

    In the past, carbon flux measurements and modelling have mostly considered the topsoil where C-concentrations, root densities and microbial activities are generally highest. However, depending on climate zone and land use, this soil compartment contains only 30-50% of the C-stocks of the first meter. If the deeper subsoil down to 3 m is also considered, the contribution of topsoil carbon stocks to total soil C-pools is only 20-40%. Another distinct property of subsoil organic matter is its high apparent 14C age. The 14C age of bulk soil organic matter below 30 cm depth generally increases continuously indicating mean residence times of several 103 to 104 years. Large pool size and high radiocarbon age suggest that subsoil OM has accumulated at very low rates over very long time periods and therefore appears to be very stable. In a review, several hypotheses for explaining why subsoil SOM is so seemingly old and inert are presented. Then a recently granted German research unit consisting of 9 subprojects from all soil science disciplines is introduced, which addresses these questions using field measurements of C-fluxes, 14C analyses and conducting field and lab experiments. 40-60% of soil C-pools are found below 40 cm depth (Data from Jobbagy & Jackson 2000).

  4. Electron capture detection of sulphur gases in carbon dioxide at the parts-per-billion level

    International Nuclear Information System (INIS)

    Pick, M.E.

    1979-01-01

    A gas chromatograph with an electron capture detector has been used to determine sulphur gases in CO 2 at the parts-per-billion level, with particular application to the analysis of coolant from CO 2 cooled nuclear reactors. For COS, CS 2 , CH 3 SH, H 2 S and (CH 3 ) 2 S 2 the detector has a sensitivity comparable with the more commonly used flame photometric detector, but it is much less sensitive towards (CH 3 ) 2 S and thiophene. In addition, the paper describes a simple method for trapping sulphur gases which might enable detection of sub parts-per-billion levels of sulphur compounds. (Auth.)

  5. Impacts of Nitrogen Fertilization on Carbon and Water Balances in Different-aged Westcoast Douglas-fir Stands

    Science.gov (United States)

    Jassal, P.; Black, A.; Bruemmer, C.; Nesic, Z.; Spittlehouse, D.; Trofymow, T.

    2009-05-01

    Using the eddy-covariance technique, we have been measuring, since 1998, CO2, water vapour and energy exchange between the atmosphere and the ecosystem in three different-aged Westcoast Douglas-fir (Pseudotsuga menziesii) stands (9, 21 and 60 year-old in 2009, hereafter known as HDF00, HDF88 and DF49, respectively). These stands were fertilized with urea in January 2007. While HDF88 and DF49 were fertilized aerially with 200 kg N ha-1, HDF00, due to its young age and competing brush, was fertilized manually at 60 kg N ha-1. This paper reports the environmental controls of pre-fertilization interannual variability in ecosystem respiration (R), gross photosynthesis (P) and evapotranspiration (E), and discusses the effects of N- fertilization on these fluxes and net ecosystem productivity (NEP = P - R, i.e., carbon sequestration) and water use efficiency (WUE = P/E). For DF49, both pre-fertilization annual P and R responded positively to increases in mean annual air temperature and soil water content, but R was more responsive to both these environmental variables. Using these relationships, we calculated P and R for 2007 and 2008 assuming the stand was not fertilized. A comparison with measured 2007 and 2008 fluxes indicated that fertilization increased P and had almost no effect on R and soil respiration with the consequence that NEP was increased by 170 and 90 g C m- 2 during 2007 and 2008, respectively. Pre-fertilization annual E was modelled as a function of mean annual temperature, annual total photosynthetically active radiation, and precipitation for the previous year. Using this model to calculate 2007 and 2008 values of E for the unfertilized stand and comparing these with measured values in the fertilized stand indicated that fertilization had no effect on E, neither in 2007 nor in 2008. As a result, annual water use efficiency increased from a mean of 4.9 g C (kg water)-1 for 1998-2006 to 5.2 g C (kg water)-1 in 2007 and 2008. A similar analysis was

  6. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    International Nuclear Information System (INIS)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D.; Jones, Edward O.; Hatano, Ryusuke

    2016-01-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha"−"1 yr"−"1 in 1959–0.26 Mg C ha"−"1 yr"−"1 in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate conditions. • NBP

  7. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate

  8. Higher Atmosphere Heating due to black carbon Over the Northern Part of India

    Science.gov (United States)

    Tiwari, S.; Singh, S., , Dr

    2017-12-01

    Light-absorbing, atmospheric particles have gained greater attention in recent years because of their direct and indirect impacts on regional and global climate. Atmospheric black carbon (BC) aerosol (also called soot particle) is a leading climate warming agent, yet uncertainties in the global direct aerosol radiative forcing remain large. Based on a year of aerosol absorption measurements at seven wavelengths, BC concentrations were investigated in Dhanbad, the coal capital of India. Coal is routinely burned for cooking and residential heat as well as in small industries. The mean daily concentrations of ultraviolet-absorbing black carbon measured at 370 nm (UVBC) and black carbon measured at 880 nm (BC) were 9.8 ± 5.7 and 6.5 ± 3.8 μg m-3, respectively. The difference between UVBC and BC, Delta-C, is an indicator of biomass or residential coal burning and averaged 3.29 ± 4.61 μg m-3. An alternative approach uses the calculation of the Angstrom Exponent (AE) to estimate the amounts of biomass/coal and traffic BC. Biomass/coal burning contributed 87% and fossil fuel combustion contributed 13% to the annual average BC concentration. In the post-monsoon season, potential source contribution function analysis showed that air masses came from the central and northwestern Indo-Gangetic Plains resulting in mean UVBC values of 10.9 μg m-3 and BC of 7.2 μg m-3. The mean winter UVBC and BC concentrations were 15.0 and 10.1 μg m-3, respectively. These highest values were largely driven by local sources under conditions of poor dispersion. The direct radiative forcing (DRF) due to UVBC and BC at the surface (SFC) and the top of the atmosphere (TOA) were calculated. The mean atmospheric heating rates due to UVBC and BC were estimated to be 1.40°K day-1 and 1.18°K day-1, respectively. This high heating rate may affect the monsoon circulation in this region.

  9. Terrestrial Carbon[Environmental Pollution: Part I, Special Issue, March 2002, Part II, Special Issue Supplement to 116/3, 2002

    International Nuclear Information System (INIS)

    Mickler, Robert; McNulty, Steven

    2002-01-01

    These issues contain a total of forty-four peer reviewed science papers on terrestrial carbon presented at the Advances in Terrestrial Ecosystem Carbon Inventory, Measurements, and Monitoring Conference held in Raleigh, N.C., in October 2000

  10. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Winton, Shea

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  11. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  12. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 5

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or {approx}28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In

  13. The sum of the parts: can we really reduce carbon emissions through individual behaviour change?

    Science.gov (United States)

    Reynolds, Lucy

    2010-01-01

    Individuals are increasingly being urged to 'do their bit' in the fight against climate change, with governments and pro-environmentalists insisting that the collective impact of small behaviour changes will result in a meaningful reduction in global carbon emissions. The following paper considers this debate, as well as offering personal contributions from two leading environmentalists: Dr Doug McKenzie-Mohr, environmental psychologist and author of Fostering Sustainable Behavior: Community-Based Social Marketing; and Dr Tom Crompton, change strategist for WWF and co-author of Meeting Environmental Challenges: The Role of Human Identity, who argues for the role of intrinsic value systems in achieving sustainable behaviour change. As well as considering the responsibility of the individual in mitigating climate change, the paper introduces the discipline of social marketing as an effective tool for facilitating individual behaviour change, drawing on evidence from the field to recommend the key characteristics of effective behaviour change programmes.

  14. Effect of Carbon Nanofiber Heat Treatment on Physical Properties of Polymeric Nanocomposites—Part I

    Directory of Open Access Journals (Sweden)

    Khalid Lafdi

    2007-01-01

    Full Text Available The definition of a nanocomposite material has broadened significantly to encompass a large variety of systems made of dissimilar components and mixed at the nanometer scale. The properties of nanocomposite materials also depend on the morphology, crystallinity, and interfacial characteristics of the individual constituents. In the current work, vapor-grown carbon nanofibers were subjected to varying heat-treatment temperatures. The strength of adhesion between the nanofiber and an epoxy (thermoset matrix was characterized by the flexural strength and modulus. Heat treatment to 1800C∘ demonstrated maximum improvement in mechanical properties over that of the neat resin, while heat-treatment to higher temperatures demonstrated a slight decrease in mechanical properties likely due to the elimination of potential bonding sites caused by the elimination of the truncated edges of the graphene layers. Both the electrical and thermal properties of the resulting nanocomposites increased in conjunction with the increasing heat-treatment temperature.

  15. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 4

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or {approx}28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In

  16. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Winton, Shea

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  17. Microwave Induced Welding of Carbon Nanotube-Thermoplastic Interfaces for Enhanced Mechanical Strength of 3D Printed Parts

    Science.gov (United States)

    Sweeney, Charles; Lackey, Blake; Saed, Mohammad; Green, Micah

    Three-dimensional (3D) printed parts produced by fused-filament fabrication of a thermoplastic polymer have become increasingly popular at both the commercial and consumer level. The mechanical integrity of these rapid-prototyped parts however, is severely limited by the interfillament bond strength between adjacent extruded layers. In this report we propose for the first time a method for welding thermoplastic interfaces of 3D printed parts using the extreme heating response of carbon nanotubes (CNTs) to microwave energy. To achieve this, we developed a coaxial printer filament with a pure polylactide (PLA) core and a CNT composite sheath. This produces parts with a thin electrically percolating network of CNTs at the interfaces between adjacent extruded layers. These interfaces are then welded together upon microwave irradiation at 2.45GHz. Our patent-pending method has been shown to increase the tensile toughness by 1000% and tensile strength by 35%. We investigated the dielectric properties of the PLA/CNT composites at microwave frequencies and performed in-situ microwave thermometry using a forward-looking infrared (FLIR) camera to characterize the heating response of the PLA/CNT composites upon microwave irradiation.

  18. Kinetic bottlenecks to chemical exchange rates for deep-sea animals - Part 2: Carbon Dioxide

    Science.gov (United States)

    Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

    2013-04-01

    Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc.) as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  19. Speciation of organic carbon in Hanford waste storage tanks: Part 1

    International Nuclear Information System (INIS)

    Carlson, C.D.

    1997-02-01

    This report is the first in a series to report on speciation of organic carbon in Hanford waste storage tanks. The comparison of the existing total organic carbon with oxalate and limited analyses of other organic species (acetate, formate, and normal paraffin hydrocarbons [NPH]) are reported. All of the data have been previously reported by the Grout and Characterization programs; the information includes all of the publicly available data through October 1996. Oxalate data were reported for 33 tanks, TOC data were reported for 82 tanks, and both oxalate and TOC data were available for 27 tanks. Of these 27 tanks, seven were found to have greater than 80% of the TOC identified as oxalate: 241-BY-104, 241-BY-105, 241-BY-106, 241-BY-110, 241-S-109, and 241-SX-108. Eighty percent accountability has been tentatively established as a minimum goal of the Organic Safety Program for speciation of TOC. Accountability of TOC through speciation will allow more accurate estimate of the potential energy content of the wastes as currently stored. Of the remaining 19 tanks, seven had between 40 and 80% of the TOC identified as oxalate, and eleven had less than 35% of the TOC identified. Of these, only five tanks had segment results that were greater than 1% TOC, and none was above 2%. Since the cur-rent safety criterion outlined in the Safety Analysis is 4.5% TOC, it may be determined that the further analyses of these tank wastes are not necessary. If additional analyses are deemed necessary, minimal work may be required, possibly limited to ion chromatography (IC), ion pair chromatography and capillary zone electrophoresis (CZE). Additional speciation work is planned for this fiscal year in both the Organic Tanks Safety and Characterization programs. The Characterization program reports acetate and formate data in addition to the oxalate data for all the tank cores it processes

  20. Kinetic bottlenecks to chemical exchange rates for deep-sea animals – Part 2: Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2013-04-01

    Full Text Available Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc. as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  1. Tropical forest carbon balance: effects of field- and satellite-based mortality regimes on the dynamics and the spatial structure of Central Amazon forest biomass

    Science.gov (United States)

    Di Vittorio, Alan V.; Negrón-Juárez, Robinson I.; Higuchi, Niro; Chambers, Jeffrey Q.

    2014-03-01

    Debate continues over the adequacy of existing field plots to sufficiently capture Amazon forest dynamics to estimate regional forest carbon balance. Tree mortality dynamics are particularly uncertain due to the difficulty of observing large, infrequent disturbances. A recent paper (Chambers et al 2013 Proc. Natl Acad. Sci. 110 3949-54) reported that Central Amazon plots missed 9-17% of tree mortality, and here we address ‘why’ by elucidating two distinct mortality components: (1) variation in annual landscape-scale average mortality and (2) the frequency distribution of the size of clustered mortality events. Using a stochastic-empirical tree growth model we show that a power law distribution of event size (based on merged plot and satellite data) is required to generate spatial clustering of mortality that is consistent with forest gap observations. We conclude that existing plots do not sufficiently capture losses because their placement, size, and longevity assume spatially random mortality, while mortality is actually distributed among differently sized events (clusters of dead trees) that determine the spatial structure of forest canopies.

  2. Tropical forest carbon balance: effects of field- and satellite-based mortality regimes on the dynamics and the spatial structure of Central Amazon forest biomass

    International Nuclear Information System (INIS)

    Di Vittorio, Alan V; Negrón-Juárez, Robinson I; Chambers, Jeffrey Q; Higuchi, Niro

    2014-01-01

    Debate continues over the adequacy of existing field plots to sufficiently capture Amazon forest dynamics to estimate regional forest carbon balance. Tree mortality dynamics are particularly uncertain due to the difficulty of observing large, infrequent disturbances. A recent paper (Chambers et al 2013 Proc. Natl Acad. Sci. 110 3949–54) reported that Central Amazon plots missed 9–17% of tree mortality, and here we address ‘why’ by elucidating two distinct mortality components: (1) variation in annual landscape-scale average mortality and (2) the frequency distribution of the size of clustered mortality events. Using a stochastic-empirical tree growth model we show that a power law distribution of event size (based on merged plot and satellite data) is required to generate spatial clustering of mortality that is consistent with forest gap observations. We conclude that existing plots do not sufficiently capture losses because their placement, size, and longevity assume spatially random mortality, while mortality is actually distributed among differently sized events (clusters of dead trees) that determine the spatial structure of forest canopies. (paper)

  3. Application of Balanced Scorecard

    OpenAIRE

    Langpaulová, Irena

    2011-01-01

    The concept of the Balanced Scorecard taking a part in the strategic management of a company, is a main focus of this thesis. There are the theoretical and methodological parts of the Balanced Scorecard characterized individually, as well as the development and the history of this concept. This thesis is dealing with a draft of the practical implementation of the mentioned methods. The practical part of the thesis is following the theoretical introduction where the practical part is focused o...

  4. Dry matter yield and Carbon partitioning in the aboveground part of switchgrass ( panicum virgatum l.) germplasm

    Energy Technology Data Exchange (ETDEWEB)

    Butkutė, B.; Lemežien ė, N.; Cesevičienė, J.; Liaudanskienė, I., E-mail: brone@lzi.lt [Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, Akademija, Kėdainiai distr. (Lithuania)

    2013-07-01

    Carbon (C) accumulated in biomass can be converted into usable forms of energy like methane, bioethanol or solid fuel. Understanding the partitioning of aboveground biomass and C plays an important role in optimizing its pre-treatment technologies. Our objectives were to determine dry matter yield (DMY) and C partitioning in switch grass germplasm. Plants were sampled at heading (HS) and seed filling (SFS) stages. The biomass of the SFS-sampled plants was separated into leaves (blades+sheaths), stems, and panicles. C content was determined by dry combustion. C yield per plant (CY) at HS ranged from 25.9 to 171 g (37.3 g on average for plants in the first harvest year, and 147 for those in the second harvest year), at SFS CY varied within a range of 79.8 ‒ 295g and averaged 119 and 252g depending on the year of growth. DMY was a weighted factor for such results. At SFS, DMY of stems accounted on average for 46.3%, leaves for 40.5%, and panicles for 13.2% of the aboveground biomass of whole plant with respective C concentrations of 462, 439 and 459 g kg -1 DM. (author)

  5. Understanding the experience of midlife women taking part in a work-life balance career coaching programme: an interpretative phenomenological analysis

    OpenAIRE

    Brown, C.; Yates, J.

    2018-01-01

    Midlife women currently have the highest ever presence in the work place with many juggling work with demanding home lives. Women are reporting increased dissatisfaction with their work - life balance yet few studies exist exploring how practical interventions might help . This action - research involved five female participants , based in Lon don, on a career coaching programme designed to improve work - life balance. Interpretative Phenomenological Analysis suggested the programme offered a...

  6. Simulation of the hot flow behaviour of a medium carbon microalloyed steel. Part 1. Theoretical approach

    International Nuclear Information System (INIS)

    Cabrera, J.M.; Prado, J.M.

    1997-01-01

    The constitutive equations to model the hot flow behaviour of metallic materials in general, and of microalloyed steels in particular (see part 2 of this work) are established in this work. Special emphasis is done on the dynamic softening mechanisms, i.e., dynamic recovery and recrystallization phenomena. The equations developed are physic-based, not empirical, and the modelling allows an easy implementation in an analysis by numerical methods. The resulting equations are even able to predict the final grain size. (Author) 39 refs

  7. Biological production in the Indian Ocean upwelling zones - Part 1: refined estimation via the use of a variable compensation depth in ocean carbon models

    Science.gov (United States)

    Geethalekshmi Sreeush, Mohanan; Valsala, Vinu; Pentakota, Sreenivas; Venkata Siva Rama Prasad, Koneru; Murtugudde, Raghu

    2018-04-01

    Biological modelling approach adopted by the Ocean Carbon-Cycle Model Intercomparison Project (OCMIP-II) provided amazingly simple but surprisingly accurate rendition of the annual mean carbon cycle for the global ocean. Nonetheless, OCMIP models are known to have seasonal biases which are typically attributed to their bulk parameterisation of compensation depth. Utilising the criteria of surface Chl a-based attenuation of solar radiation and the minimum solar radiation required for production, we have proposed a new parameterisation for a spatially and temporally varying compensation depth which captures the seasonality in the production zone reasonably well. This new parameterisation is shown to improve the seasonality of CO2 fluxes, surface ocean pCO2, biological export and new production in the major upwelling zones of the Indian Ocean. The seasonally varying compensation depth enriches the nutrient concentration in the upper ocean yielding more faithful biological exports which in turn leads to accurate seasonality in the carbon cycle. The export production strengthens by ˜ 70 % over the western Arabian Sea during the monsoon period and achieves a good balance between export and new production in the model. This underscores the importance of having a seasonal balance in the model export and new productions for a better representation of the seasonality of the carbon cycle over upwelling regions. The study also implies that both the biological and solubility pumps play an important role in the Indian Ocean upwelling zones.

  8. Shifting the Arctic Carbon Balance: Effects of a Long-Term Fertilization Experiment and Anomalously Warm Temperatures on Net Ecosystem Exchange in the Alaskan Tundra

    Science.gov (United States)

    Ludwig, S.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Graham, L. M.; Jastrow, J. D.

    2017-12-01

    The arctic is warming at an accelerated rate relative to the globe. Among the predicted consequences of warming temperatures in the arctic are increased gross primary productivity (GPP), ecosystem respiration (ER), and nutrient availability. The net effect of these changes on the carbon (C) cycle and resulting C balance and feedback to climate change remain unclear. Historically the Arctic has been a C sink, but evidence from recent years suggests some regions in the Arctic are becoming C sources. To predict the role of the Arctic in global C cycling, the mechanisms affecting arctic C balances need to be better resolved. We measured net ecosystem exchange (NEE) in a long-term, multi-level, fertilization experiment at Toolik Lake, AK during an anomalously warm summer. We modeled NEE, ER, and GPP using a Bayesian network model. The best-fit model included Q10 temperature functions and linear fertilization functions for both ER and GPP. ER was more strongly affected by temperature and GPP was driven more by fertilization level. As a result, fertilization increased the C sink capacity, but only at moderate and low temperatures. At high temperatures (>28 °C) the NEE modeled for the highest level of fertilization was not significantly different from zero. In contrast, at ambient nutrient levels modeled NEE was significantly below zero (net uptake) until 35 °C, when it becomes neutral. Regardless of the level of fertilization, NEE never decreased with warming. Temperature in low ranges (5-15°C) had no net effect on NEE, whereas NEE began to increase exponentially with temperature after a threshold of 15°C until becoming a net source to the atmosphere at 37°C. Our results indicate that the C sink strength of tundra ecosystems can be increased with small increases in nutrient availability, but that large increase in nutrient availability can switch tundra ecosystems into C sources under warm conditions. Warming temperatures in tundra ecosystems will only decrease C

  9. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part I. Black carbon.

    Science.gov (United States)

    Wang, Yang; Xing, Zhenyu; Xu, Hui; Du, Ke

    2016-12-01

    Compressed natural gas (CNG) is considered to be a "cleaner" fuel compared to other fossil fuels. Therefore, it is used as an alternative fuel in motor vehicles to reduce emissions of air pollutants in transportation. To quantify "how clean" burning CNG is compared to burning gasoline, quantification of pollutant emissions under the same driving conditions for motor vehicles with different fuels is needed. In this study, a fleet of bi-fuel vehicles was selected to measure the emissions of black carbon (BC), carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NO x ) for driving in CNG mode and gasoline mode respectively under the same set of constant speeds and accelerations. Comparison of emission factors (EFs) for the vehicles burning CNG and gasoline are discussed. This part of the paper series reports BC EFs for bi-fuel vehicles driving on the real road, which were measured using an in situ method. Our results show that burning CNG will lead to 54%-83% reduction in BC emissions per kilometer, depending on actual driving conditions. These comparisons show that CNG is a cleaner fuel than gasoline for motor vehicles in terms of BC emissions and provide a viable option for reducing BC emissions cause by transportation. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. An improved parameterization of the allocation of assimilated carbon to plant parts in vegetation dynamics for Noah-MP

    Science.gov (United States)

    Gim, Hyeon-Ju; Park, Seon Ki; Kang, Minseok; Thakuri, Bindu Malla; Kim, Joon; Ho, Chang-Hoi

    2017-08-01

    In the land surface models predicting vegetation growth and decay, representation of the seasonality of land surface energy and mass fluxes largely depends on how to describe the vegetation dynamics. In this study, we developed a new parameterization scheme to characterize allocation of the assimilated carbon to plant parts, including leaves and fine roots. The amount of carbon allocation in this scheme depends on the climatological net primary production (NPP) of the plants. The newly developed scheme is implemented in the augmented Noah land surface model with multiple parameterization options (Noah-MP) along with other biophysical processes related to variations in photosynthetic capacity. The scheme and the augmented biophysical processes are evaluated against tower measurements of vegetation from four forest sites in various regions—two for the deciduous broadleaf and two for the needleleaf evergreen forest. Results from the augmented Noah-MP showed good agreement with the observations and demonstrated improvements in representing the seasonality of leaf area index (LAI), gross primary production (GPP), ecosystem respiration (ER), and latent heat flux. In particular, significant improvements are found in simulating amplitudes and phase shift timing in the LAI seasonal cycle, and the amount of GPP and ER in the growing season. Furthermore, the augmented Noah-MP performed reasonably well in simulating the spatial distributions of LAI, GPP, and NPP in East Asia, consistent with the satellite observations.

  11. Convergence of the effect of root hydraulic functioning and root hydraulic redistribution on ecosystem water and carbon balance across divergent forest ecosystems

    Science.gov (United States)

    domec, J.; King, J. S.; Ogée, J.; Noormets, A.; Warren, J.; Meinzer, F. C.; Sun, G.; Jordan-Meille, L.; Martineau, E.; Brooks, R. J.; Laclau, J.; Battie Laclau, P.; McNulty, S.

    2012-12-01

    trees to droughts. Under future conditions, T is predicted to stay the same at the Duke mixed hardwood forest, but to decline slightly at the coastal loblolly pine plantation and slightly increase at the old-growth ponderosa pine stand and the eucalyptus plantation. As a consequence, water use efficiency in all sites was predicted to improve dramatically under future climate conditions. Our simulations also showed that the negative effect of drier nights on HR would be greater under future climate conditions. Assuming no increase in stomatal control with increasing drier nights, increased vapor pressure deficit at night under future conditions was sufficient to drive significant nighttime T at all sites , which reduced HR, because the plant and the atmosphere became a sink for hydraulically redistributed water . We concluded that the predicted reductions in HR under future climate conditions are expected to play an important regulatory role in land-atmosphere interactions by affecting whole ecosystem carbon and water balance. We suggest that root distribution should be treated dynamically in response to climate change and that HR and its interactions with rooting depth and soil texture should be implemented in soil-vegetation-atmosphere transfer models.

  12. Achieving Work-Life Balance in the National Collegiate Athletic Association Division I Setting, Part I: The Role of the Head Athletic Trainer

    Science.gov (United States)

    Mazerolle, Stephanie M.; Goodman, Ashley; Pitney, William A.

    2015-01-01

    Context: Supervisor support has been identified as key to the fulfillment of work-life balance for the athletic trainer (AT), yet limited literature exists on the perspectives of supervisors. Objective: To investigate how the head AT facilitates work-life balance among staff members within the National Collegiate Athletic Association Division I setting. Design: Qualitative study. Setting: Web-based management system. Patients or Other Participants: A total of 18 head ATs (13 men, 5 women; age = 44 ± 8 years, athletic training experience = 22 ± 7 years) volunteered for an asynchronous, Web-based interview. Data Collection and Analysis: Participants responded to a series of questions by journaling their thoughts and experiences. We included multiple-analyst triangulation, stakeholder checks, and peer review to establish data credibility. We analyzed the data via a general inductive approach. Results: Four prevailing themes emerged from the data: modeling work-life balance, encouraging disengagement from the AT role, cooperation and community workplace, and administrative support and understanding. Conclusions: Head ATs at the Division I level recognized the need to promote work-life balance among their staffs. They not only were supportive of policies that promote work-life balance, including spending time away from the role of the AT and teamwork among staff members, but also modeled and practiced the strategies that they promoted. PMID:25343530

  13. Achieving work-life balance in the National Collegiate Athletic Association Division I setting, part I: the role of the head athletic trainer.

    Science.gov (United States)

    Mazerolle, Stephanie M; Goodman, Ashley; Pitney, William A

    2015-01-01

    Supervisor support has been identified as key to the fulfillment of work-life balance for the athletic trainer (AT), yet limited literature exists on the perspectives of supervisors. To investigate how the head AT facilitates work-life balance among staff members within the National Collegiate Athletic Association Division I setting. Qualitative study. Web-based management system. A total of 18 head ATs (13 men, 5 women; age = 44 ± 8 years, athletic training experience = 22 ± 7 years) volunteered for an asynchronous, Web-based interview. Participants responded to a series of questions by journaling their thoughts and experiences. We included multiple-analyst triangulation, stakeholder checks, and peer review to establish data credibility. We analyzed the data via a general inductive approach. Four prevailing themes emerged from the data: modeling work-life balance, encouraging disengagement from the AT role, cooperation and community workplace, and administrative support and understanding. Head ATs at the Division I level recognized the need to promote work-life balance among their staffs. They not only were supportive of policies that promote work-life balance, including spending time away from the role of the AT and teamwork among staff members, but also modeled and practiced the strategies that they promoted.

  14. Emulating atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 – Part 2: Applications

    Directory of Open Access Journals (Sweden)

    M. Meinshausen

    2011-02-01

    Full Text Available Intercomparisons of coupled atmosphere-ocean general circulation models (AOGCMs and carbon cycle models are important for galvanizing our current scientific knowledge to project future climate. Interpreting such intercomparisons faces major challenges, not least because different models have been forced with different sets of forcing agents. Here, we show how an emulation approach with MAGICC6 can address such problems. In a companion paper (Meinshausen et al., 2011a, we show how the lower complexity carbon cycle-climate model MAGICC6 can be calibrated to emulate, with considerable accuracy, globally aggregated characteristics of these more complex models. Building on that, we examine here the Coupled Model Intercomparison Project's Phase 3 results (CMIP3. If forcing agents missed by individual AOGCMs in CMIP3 are considered, this reduces ensemble average temperature change from pre-industrial times to 2100 under SRES A1B by 0.4 °C. Differences in the results from the 1980 to 1999 base period (as reported in IPCC AR4 to 2100 are negligible, however, although there are some differences in the trajectories over the 21st century. In a second part of this study, we consider the new RCP scenarios that are to be investigated under the forthcoming CMIP5 intercomparison for the IPCC Fifth Assessment Report. For the highest scenario, RCP8.5, relative to pre-industrial levels, we project a median warming of around 4.6 °C by 2100 and more than 7 °C by 2300. For the lowest RCP scenario, RCP3-PD, the corresponding warming is around 1.5 °C by 2100, decreasing to around 1.1 °C by 2300 based on our AOGCM and carbon cycle model emulations. Implied cumulative CO2 emissions over the 21st century for RCP8.5 and RCP3-PD are 1881 GtC (1697 to 2034 GtC, 80% uncertainty range and 381 GtC (334 to 488 GtC, when prescribing CO2 concentrations and accounting for uncertainty in the carbon cycle. Lastly, we assess the reasons why a previous MAGICC

  15. Arabidopsis thaliana ggt1 photorespiratory mutants maintain leaf carbon/nitrogen balance by reducing RuBisCO content and plant growth.

    Science.gov (United States)

    Dellero, Younès; Lamothe-Sibold, Marlène; Jossier, Mathieu; Hodges, Michael

    2015-09-01

    Metabolic and physiological analyses of glutamate:glyoxylate aminotransferase 1 (GGT1) mutants were performed at the global leaf scale to elucidate the mechanisms involved in their photorespiratory growth phenotype. Air-grown ggt1 mutants showed retarded growth and development, that was not observed at high CO2 (3000 μL L(-1) ). When compared to wild-type (WT) plants, air-grown ggt1 plants exhibited glyoxylate accumulation, global changes in amino acid amounts including a decrease in serine content, lower organic acid levels, and modified ATP/ADP and NADP(+) /NADPH ratios. When compared to WT plants, their net CO2 assimilation rates (An ) were 50% lower and this mirrored decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents. High CO2 -grown ggt1 plants transferred to air revealed a rapid decrease of An and photosynthetic electron transfer rate while maintaining a high energetic state. Short-term (a night period and 4 h of light) transferred ggt1 leaves accumulated glyoxylate and exhibited low serine contents, while other amino acid levels were not modified. RuBisCO content, activity and activation state were not altered after a short-term transfer while the ATP/ADP ratio was lowered in ggt1 rosettes. However, plant growth and RuBisCO levels were both reduced in ggt1 leaves after a long-term (12 days) acclimation to air from high CO2 when compared to WT plants. The data are discussed with respect to a reduced photorespiratory carbon recycling in the mutants. It is proposed that the low An limits nitrogen-assimilation, this decreases leaf RuBisCO content until plants attain a new homeostatic state that maintains a constant C/N balance and leads to smaller, slower growing plants. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  16. Very high resolution regional climate simulations on the 4 km scale as a basis for carbon balance assessments in northeast European Russia

    Science.gov (United States)

    Stendel, Martin; Hesselbjerg Christensen, Jens; Adalgeirsdottir, Gudfinna; Rinke, Annette; Matthes, Heidrun; Marchenko, Sergej; Daanen, Ronald; Romanovsky, Vladimir

    2010-05-01

    Simulations with global circulation models (GCMs) clearly indicate that major climate changes in polar regions can be expected during the 21st century. Model studies have shown that the area of the Northern Hemisphere underlain by permafrost could be reduced substantially in a warmer climate. However, thawing of permafrost, in particular if it is ice-rich, is subject to a time lag due to the large latent heat of fusion. State-of-the-art GCMs are unable to adequately model these processes because (a) even the most advanced subsurface schemes rarely treat depths below 5 m explicitly, and (b) soil thawing and freezing processes cannot be dealt with directly due to the coarse resolution of present GCMs. Any attempt to model subsurface processes needs information about soil properties, vegetation and snow cover, which are hardly realistic on a typical GCM grid. Furthermore, simulated GCM precipitation is often underestimated and the proportion of rain and snow is incorrect. One possibility to overcome resolution-related problems is to use regional climate models (RCMs). Such an RCM, HIRHAM, has until now been the only one used for the entire circumpolar domain, and its most recent version, HIRHAM5, has also been used in the high resolution study described here. Instead of the traditional approach via a degree-day based frost index from observations or model data, we use the regional model to create boundary conditions for an advanced permafrost model. This approach offers the advantage that the permafrost model can be run on the grid of the regional model, i.e. in a considerably higher resolution than in previous approaches. We here present results from a new time-slice integration with an unprecedented horizontal resolution of only 4 km, covering northeast European Russia. This model simulation has served as basis for an assessment of the carbon balance for a region in northeast European Russia within the EU-funded Carbo-North project.

  17. Russia - Nato. The military balance

    OpenAIRE

    Daugaard, Søren Bech; Jacobsen, Karen Vestergård; Aigro, Signe; Skarequist, Anne

    2010-01-01

    This project aims to explain how the military balancing of Russia against NATO can be explained from a neoclassical realist framework. The project consists in three analytical parts of respectively, 1: The military capabilities balance between NATO and Russia; 2: How the international system puts pressure on Russia; and 3: How the strategic culture of Russia can explain its balancing. This project aims to explain how the military balancing of Russia against NATO can be explained from a neo...

  18. Achieving work-life balance in the National Collegiate Athletic Association Division I setting, part II: perspectives from head athletic trainers.

    Science.gov (United States)

    Goodman, Ashley; Mazerolle, Stephanie M; Pitney, William A

    2015-01-01

    Work-life balance has been examined at the collegiate level from multiple perspectives except for the athletic trainer (AT) serving in a managerial or leadership role. To investigate challenges and strategies used in achieving work-life balance from the perspective of the head AT at a National Collegiate Athletic Association Division I university. Qualitative study. Web-based management system. A total of 18 head ATs (13 men, 5 women; age = 44 ± 8 years, athletic training experience = 22 ± 7 years) volunteered. Participants journaled their thoughts and experiences in response to a series of questions. To establish data credibility, we included multiple-analyst triangulation, stakeholder checks, and peer review. We used a general inductive approach to analyze the data. Two higher-order themes emerged from our analysis of the data: organizational challenges and work-life balance strategies. The organizational challenges theme contained 2 lower-order themes: lack of autonomy and role demands. The work-life balance strategies theme contained 3 lower-order themes: prioritization of commitments, strategic boundary setting, and work-family integration. Head ATs are susceptible to experiencing work-life imbalance just as ATs in nonsupervisory roles are. Although not avoidable, the causes are manageable. Head ATs are encouraged to prioritize their personal time, make efforts to spend time away from their demanding positions, and reduce the number of additional responsibilities that can impede time available to spend away from work.

  19. Balancing Work and Family: A Panel Analysis of the Impact of Part-Time Work on the Experience of Time Pressure

    Science.gov (United States)

    Laurijssen, Ilse; Glorieux, Ignace

    2013-01-01

    In this article we consider the consequences of work-family reconciliation, in terms of the extent to which the adjustment of the labour market career to family demands (by women) contributes to a better work-life balance. Using the Flemish SONAR-data, we analyse how changes in work and family conditions between the age of 26 and 29 are related to…

  20. Associations of leisure-time physical activity with balance and lower extremity strength: a validation of the neuromuscular part of the Physical Activity Pie.

    Science.gov (United States)

    Lindström, Paula J; Suni, Jaana H; Nygård, Clas-Håkan

    2009-07-01

    The importance of neuromuscular-type exercise (NME) has been recognized in recent recommendations for public health. However, the knowledge on associations and dose response of different types of leisure-time physical activity (LTPA) with musculoskeletal fitness and health is incomplete. This study evaluated the validity of the NME recommendation for public health introduced by the Physical Activity Pie. Engagement in LTPA and health-related fitness were assessed in 2 consecutive studies with the same adult population age 30 to 69 years (n = 575). Cross-sectional associations between different LTPA types and motor and musculoskeletal fitness were examined by logistic-regression models. Engagement in NME was associated with good static and dynamic balance and lower extremity strength. The highest odds ratios (OR) were found between brisk NME and static balance (most vs least fit OR = 2.39, moderate vs least fit OR = 1.94) and brisk NME and leg strength (more vs least fit OR = 2.10). Some associations were also found between brisk aerobic exercise and good balance. This cross-sectional study suggests that the recommendation for NME in the Physical Activity Pie is valid in terms of balance and leg strength, the 2 major fitness factors related to mobility functioning, especially among aging adults.

  1. The energy balance experiment EBEX-2000. Part II: Intercomparison of eddy-covariance sensors and post-field data processing methods

    NARCIS (Netherlands)

    Mauder, M.; Oncley, S.P.; Vogt, R.; Weidinger, T.; Ribeiro, L.; Bernhofer, C.; Foken, T.; Kohsiek, W.; Bruin, de H.A.R.; Liu, H.

    2007-01-01

    The eddy-covariance method is the primary way of measuring turbulent fluxes directly. Many investigators have found that these flux measurements often do not satisfy a fundamental criterion¿closure of the surface energy balance. This study investigates to what extent the eddy-covariance measurement

  2. Balancing Audio

    DEFF Research Database (Denmark)

    Walther-Hansen, Mads

    2016-01-01

    is not thoroughly understood. In this paper I treat balance as a metaphor that we use to reason about several different actions in music production, such as adjusting levels, editing the frequency spectrum or the spatiality of the recording. This study is based on an exploration of a linguistic corpus of sound......This paper explores the concept of balance in music production and examines the role of conceptual metaphors in reasoning about audio editing. Balance may be the most central concept in record production, however, the way we cognitively understand and respond meaningfully to a mix requiring balance...

  3. Research on self-calibration method of vehicle fuel consumption instrument based on carbon balance method%碳平衡法汽车燃料消耗量检测仪自校准方法探究

    Institute of Scientific and Technical Information of China (English)

    戴晓锋

    2016-01-01

    Carbon content in the fuel is equal to the carbon content in the exhaust gas after combustion in the engine. According to the law of mass conservation, the measurement of vehicle fuel consumption can be achieved by vehicle fuel consumption instrument based on carbon balance method. Available time of vehicle fuel consumption instrument based on carbon balance method is not long in our country and there is no verification institution to the test, so Self-calibration of the inspection body wil become normal for a certain period of time.%燃料中所含碳质量与燃料在发动机中燃烧后排气中所含碳质量相等,根据质量守衡定律,碳平衡法汽车燃料消耗量检测仪实现对汽车燃料消耗量的测量。碳平衡法汽车燃料消耗量检测仪在我国面世时间不长,尚无检定机构能对其检定,因此,检验机构自校准在一定时间将会成为常态。

  4. Drivers of soil organic matter vulnerability to climate change, Part II: RothC modelling of carbon dynamics including radiocarbon data

    Science.gov (United States)

    Studer, Mirjam S.; Abiven, Samuel; González Domínguez, Beatriz R.; Hagedorn, Frank; Reisser, Moritz; Walthert, Lorenz; Zimmermann, Stephan; Niklaus, Pascal A.

    2016-04-01

    It is still largely unknown what drives the vulnerability of soil organic carbon (SOC) stocks to climate change, i.e. the likelihood of a soil to loose its SOC along with the change in environmental conditions. Our objective is to assess the SOC vulnerability of Swiss forest soils and identify its potential drivers: climate (temperature, soil moisture), soil (clay content, pH) and landscape (slope, aspect) properties. Fifty-four sites were selected for balanced spatial and driver magnitudes distribution. We measured the SOC characteristics (content and radiocarbon) and studied the C decomposition by laboratory soil incubations (details in Part I, abstract by B. González Domínguez). In order to assess the current SOC pool distribution and its radiocarbon signatures, we extended the Rothamsted Carbon (RothC) model with radiocarbon (14C) isotope modelling (RothCiso). The RothC model distinguishes four active SOC pools, decomposable and resistant plant material, microbial biomass and humified organic matter, and an inert SOC pool (Jenkinson 1990). The active pools are decomposed and mineralized to CO2 by first order kinetics. The RothCiso assigns all pools a 14C signature, based on the atmospheric 14C concentrations of the past century (plant C inputs) and their turnover. Currently we constrain the model with 14C signatures measured on the 54 fresh and their corresponding archived bulk soil samples, taken 12-24 years before. We were able to reproduce the measured radiocarbon concentrations of the SOC with the RothCiso and first results indicate, that the assumption of an inert SOC pool, that is radiocarbon dead, is not appropriate. In a second step we will compare the SOC mean residence time assessed by the two methodological approaches - incubation (C efflux based) and modelling (C stock based) - and relate it to the environmental drivers mentioned above. With the combination of the two methodological approaches and 14C analysis we hope to gain more insights into

  5. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  6. Achieving Work-Life Balance in the National Collegiate Athletic Association Division I Setting, Part II: Perspectives From Head Athletic Trainers

    Science.gov (United States)

    Goodman, Ashley; Mazerolle, Stephanie M.; Pitney, William A.

    2015-01-01

    Context: Work-life balance has been examined at the collegiate level from multiple perspectives except for the athletic trainer (AT) serving in a managerial or leadership role. Objective: To investigate challenges and strategies used in achieving work-life balance from the perspective of the head AT at a National Collegiate Athletic Association Division I university. Design: Qualitative study. Setting: Web-based management system. Patients or Other Participants: A total of 18 head ATs (13 men, 5 women; age = 44 ± 8 years, athletic training experience = 22 ± 7 years) volunteered. Data Collection and Analysis: Participants journaled their thoughts and experiences in response to a series of questions. To establish data credibility, we included multiple-analyst triangulation, stakeholder checks, and peer review. We used a general inductive approach to analyze the data. Results: Two higher-order themes emerged from our analysis of the data: organizational challenges and work-life balance strategies. The organizational challenges theme contained 2 lower-order themes: lack of autonomy and role demands. The work-life balance strategies theme contained 3 lower-order themes: prioritization of commitments, strategic boundary setting, and work-family integration. Conclusions: Head ATs are susceptible to experiencing work-life imbalance just as ATs in nonsupervisory roles are. Although not avoidable, the causes are manageable. Head ATs are encouraged to prioritize their personal time, make efforts to spend time away from their demanding positions, and reduce the number of additional responsibilities that can impede time available to spend away from work. PMID:25098746

  7. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant

    Science.gov (United States)

    Boothe, W. A.; Corman, J. C.; Johnson, G. G.; Cassel, T. A. V.

    1976-01-01

    Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included.

  8. A Systematic Review of the Association Between Physical Fitness and Musculoskeletal Injury Risk: Part 3 - Flexibility, Power, Speed, Balance, and Agility.

    Science.gov (United States)

    de la Motte, Sarah J; Lisman, Peter; Gribbin, Timothy C; Murphy, Kaitlin; Deuster, Patricia A

    2017-12-11

    We performed a systematic review and evaluation of the existing scientific literature on the association between flexibility, power, speed, balance, and agility, and musculoskeletal injury (MSK-I) risk in military and civilian populations. MEDLINE, EBSCO, EMBASE, and the Defense Technical Information Center were searched for original studies published from 1970 through 2015 that examined associations between these physical fitness measures (flexibility, power, speed, balance, and agility) and MSK-I. Methodological quality and strength of the evidence were determined following criteria adapted from previously published systematic reviews. Twenty-seven of 4,229 citations met our inclusion criteria. Primary findings indicate there is (a) moderate evidence that hamstring flexibility, as measured by performance on a sit-and-reach test or active straight-leg raise test assessed with goniometry, and ankle flexibility, assessed with goniometry, are associated with MSK-I risk; (b) moderate evidence that lower body power, as measured by performance on a standing broad jump or vertical jump with no countermovement, is associated with MSK-I risk; (c) moderate evidence that slow sprint speed is associated with MSK-I risk; (d) moderate evidence that poor performance on a single-leg balance test is associated with increased risk for ankle sprain; and (e) insufficient evidence that agility is associated with MSK-I risk. Several measures of flexibility, power, speed, and balance are risk factors for training-related MSK-I in military and civilian athletic populations. Importantly, these findings can be useful for military, first responder, and athletic communities who are seeking evidence-based metrics for assessing or stratifying populations for risk of MSK-I.

  9. The energy balance experiment EBEX-2000. Part II: Intercomparison of eddy-covariance sensors and post-field data processing methods

    OpenAIRE

    Mauder, M.; Oncley, S.P.; Vogt, R.; Weidinger, T.; Ribeiro, L.; Bernhofer, C.; Foken, T.; Kohsiek, W.; Bruin, de, H.A.R.; Liu, H.

    2007-01-01

    The eddy-covariance method is the primary way of measuring turbulent fluxes directly. Many investigators have found that these flux measurements often do not satisfy a fundamental criterion¿closure of the surface energy balance. This study investigates to what extent the eddy-covariance measurement technology can be made responsible for this deficiency, in particular the effects of instrumentation or of the post-field data processing. Therefore, current eddy-covariance sensors and several pos...

  10. Cómo resolver un balance de energía CON reacción química - parte 1

    OpenAIRE

    Fernandez-Torres, Maria J.

    2013-01-01

    Ejemplo de cómo encontrar el valor de "incremento de entalpía" para resolver un balance de energía dentro de la disciplina de la Ingeniería Química. Para el cálculo que se presenta se utilizan los valores de entalpías de formación de las sustancias que intervienen en la reacción química.

  11. Vibration impact acoustic emission technique for identification and analysis of defects in carbon steel tubes: Part B Cluster analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Zakiah Abd [Universiti Teknikal Malaysia Melaka (Malaysia); Jamaludin, Nordin; Junaidi, Syarif [Faculty of Engineering and Built, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Yahya, Syed Yusainee Syed [Universiti Teknologi MARA, Shah Alam (Malaysia)

    2015-04-15

    Current steel tubes inspection techniques are invasive, and the interpretation and evaluation of inspection results are manually done by skilled personnel. Part A of this work details the methodology involved in the newly developed non-invasive, non-destructive tube inspection technique based on the integration of vibration impact (VI) and acoustic emission (AE) systems known as the vibration impact acoustic emission (VIAE) technique. AE signals have been introduced into a series of ASTM A179 seamless steel tubes using the impact hammer. Specifically, a good steel tube as the reference tube and four steel tubes with through-hole artificial defect at different locations were used in this study. The AEs propagation was captured using a high frequency sensor of AE systems. The present study explores the cluster analysis approach based on autoregressive (AR) coefficients to automatically interpret the AE signals. The results from the cluster analysis were graphically illustrated using a dendrogram that demonstrated the arrangement of the natural clusters of AE signals. The AR algorithm appears to be the more effective method in classifying the AE signals into natural groups. This approach has successfully classified AE signals for quick and confident interpretation of defects in carbon steel tubes.

  12. Vibration impact acoustic emission technique for identification and analysis of defects in carbon steel tubes: Part B Cluster analysis

    International Nuclear Information System (INIS)

    Halim, Zakiah Abd; Jamaludin, Nordin; Junaidi, Syarif; Yahya, Syed Yusainee Syed

    2015-01-01

    Current steel tubes inspection techniques are invasive, and the interpretation and evaluation of inspection results are manually done by skilled personnel. Part A of this work details the methodology involved in the newly developed non-invasive, non-destructive tube inspection technique based on the integration of vibration impact (VI) and acoustic emission (AE) systems known as the vibration impact acoustic emission (VIAE) technique. AE signals have been introduced into a series of ASTM A179 seamless steel tubes using the impact hammer. Specifically, a good steel tube as the reference tube and four steel tubes with through-hole artificial defect at different locations were used in this study. The AEs propagation was captured using a high frequency sensor of AE systems. The present study explores the cluster analysis approach based on autoregressive (AR) coefficients to automatically interpret the AE signals. The results from the cluster analysis were graphically illustrated using a dendrogram that demonstrated the arrangement of the natural clusters of AE signals. The AR algorithm appears to be the more effective method in classifying the AE signals into natural groups. This approach has successfully classified AE signals for quick and confident interpretation of defects in carbon steel tubes.

  13. Sustainable gasification–biochar systems? A case-study of rice-husk gasification in Cambodia, Part II: Field trial results, carbon abatement, economic assessment and conclusions

    International Nuclear Information System (INIS)

    Shackley, Simon; Carter, Sarah; Knowles, Tony; Middelink, Erik; Haefele, Stephan; Haszeldine, Stuart

    2012-01-01

    In part I we described the gasification technology and characterised the physio-chemical properties and environmental impacts of the rice husk char (RHC) by-product. In part II we present summary results from field trials using the RHC, and provide an estimate of the carbon abatement and economic evaluation of the system. Statistically significant yield increases are demonstrated for RHC addition in irrigated rice cultivation (33% increase in paddy rice yield for a 41.5 t (dry weight) RHC application per hectare). The carbon abatement from the RHC addition is approximately 0.42 t CO 2 t −1 rice husk; including energy generation from gasification this increases to ca. 0.86 tCO 2 t −1 . Assuming a carbon value of $5 t CO 2 t −1 , and agronomic value of $3 t −1 RHC based on the field trials, the economic value of the RHC varies from $9 t −1 (including only recalcitrant carbon) to $15 t −1 (including avoided emissions from energy production). We summarise results from parts I and II, concluding that the gasification–biochar system meets many of the criteria of sustainability, but requires better waste water management and more field trials to demonstrate repeatable agronomic efficacy of RHC application. - Highlights: ► Field trials show statistically significant rice yield increases using rice husk char (RHC). ► Carbon abatement of 0.42 t CO 2 t −1 rice husk from RHC production. ► Bioenergy generation via gasification gives carbon abatement of 0.44 t CO 2 t −1 husk. ► Total carbon abatement is therefore ca. 0.86 t CO 2 t −1 husk. ► Agronomic value from trials is $3 t −1 char; assuming $5 CO 2 t −1 , the total value of RHC is $9–$15 t −1 .

  14. Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA

    Science.gov (United States)

    Plummer, Niel; Sprinkle, Craig

    2001-03-01

    Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and (4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting, at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20-30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰. Résumé. Les modèles de réactions géochimiques ont été évalués afin de tester la datation par le radiocarbone du carbone minéral dissous (CMD) des eaux souterraines dans les parties captives de la nappe supérieure de Floride, en Floride centrale et nord-orientale (États-Unis). Les réactions géochimiques prédominantes affectant l'activité en 14C du CMD comprennent (1) la dissolution de la dolomite et de l'anhydrite accompagnée de la précipitation de la calcite (d

  15. Analysis of first and second law of an engine operating with Bio diesel from palm oil. Part 2: global exergy balance

    International Nuclear Information System (INIS)

    Agudelo, John R; Agudelo, Andres F; Cuadrado, Ilba G

    2006-01-01

    An exergy analysis of a diesel engine operating with palm oil bio diesel and its blends with diesel fuel is presented. Measurements were carried out in a test bench under stationary conditions varying engine load at constant speed and vice versa. The variation in exergy distribution and second law efficiency were obtained under several operating points. It was found that fuel type do not affect exergy distribution but it does affect the second law efficiency, which is slightly higher for diesel fuel. In contrast with energy balance results, exergy flows of exhaust and coolant streams are low, specially for the latter. This result is relevant for the implementation of cogeneration systems.

  16. The Work-Study Nexus: The Challenges of Balancing Full-Time Business Degree Study with a Part-Time Job

    Science.gov (United States)

    Richardson, Mark; Evans, Carl; Gbadamosi, Gbolahan

    2014-01-01

    This study examined how full-time university students cope with part-time working during term time. A qualitative approach was used to examine how students simultaneously manage the two activities, and how part-time working affects their academic study. Semi-structured interviews were used to obtain data from a sample of 30 undergraduate business…

  17. Role of cavity formation in SCC of cold worked carbon steel in high-temperature water. Part 2. Study of crack initiation behavior

    International Nuclear Information System (INIS)

    Yamada, Takuyo; Aoki, Masanori; Miyamoto, Tomoki; Arioka, Koji

    2013-01-01

    To consider the role of cavity formation in stress corrosion cracking (SCC) of cold worked (CW) carbon steel in high-temperature water, SCC and creep growth (part 1) and initiation (part 2) tests were performed. The part 2 crack initiation tests used blunt notched compact tension (CT) type specimens of CW carbon steel exposed under the static load condition in hydrogenated pure water and in air in the range of temperatures between 360 and 450°C. Inter-granular (IG) crack initiation was observed both in water and in air even in static load condition when steel specimens had been cold worked. 1/T type temperature dependencies of initiation times were observed for CW carbon steel, and the crack initiation times in an operating pressurized heavy water reactor, PHWR (Pt Lepreau) seemed to lie on the extrapolated line of the experimental results. Cavities were identified at the grain boundaries near the bottom of a notch (highly stressed location) before cracks initiated both in water and air. The cavities were probably formed by the condensation of vacancies and they affected the bond strength of the grain boundaries. To assess the mechanism of IGSCC initiation in high temperature water, the diffusion of vacancies driven by stress gradients was studied using a specially designed CT specimen. As a model for IGSCC in CW carbon steel in high temperature water, it was concluded that the formation of cavities from the collapse of vacancies offers the best interpretation of the present data. (author)

  18. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  19. Comparing the applicability of some geostatistical methods to predict the spatial distribution of topsoil Calcium Carbonate in part of farmland of Zanjan Province

    Science.gov (United States)

    Sarmadian, Fereydoon; Keshavarzi, Ali

    2010-05-01

    Most of soils in iran, were located in the arid and semi-arid regions and have high pH (more than 7) and high amount of calcium carbonate and this problem cause to their calcification.In calcareous soils, plant growing and production is difficult. Most part of this problem, in relation to high pH and high concentration of calcium ion that cause to fixation and unavailability of elements which were dependent to pH, especially Phosphorous and some micro nutrients such as Fe, Zn, Mn and Cu. Prediction of soil calcium carbonate in non-sampled areas and mapping the calcium carbonate variability in order to sustainable management of soil fertility is very important.So, this research was done with the aim of evaluation and analyzing spatial variability of topsoil calcium carbonate as an aspect of soil fertility and plant nutrition, comparing geostatistical methods such as kriging and co-kriging and mapping topsoil calcium carbonate. For geostatistical analyzing, sampling was done with stratified random method and soil samples from 0 to 15 cm depth were collected with auger within 23 locations.In co-kriging method, salinity data was used as auxiliary variable. For comparing and evaluation of geostatistical methods, cross validation were used by statistical parameters of RMSE. The results showed that co-kriging method has the highest correlation coefficient and less RMSE and has the higher accuracy than kriging method to prediction of calcium carbonate content in non-sampled areas.

  20. Alternative methodology for assessing part-through-wall cracks in carbon steel bends removed from Point Lepreau Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Duan Xinjian, E-mail: duanx@aecl.c [Senior Engineer, Reactor Engineering Department, Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Kozluk, Michael J., E-mail: kozlukm@aecl.c [Independent Consultant, Oakville, ON (Canada); Gendron, Tracy [Manager-HTS Materials Integrity, Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Slade, John [Senior Technical Advisor, Point Lepreau Generating Station, Lepreau, NB (Canada)

    2011-03-15

    In 2008 April Point Lepreau Generating Station entered an extended refurbishment outage that will involve the replacement of key reactor components (fuel channels and connecting feeder pipes). Prior to the refurbishment outage, New Brunswick Power Nuclear had been successfully managing intergranular, axial cracking of carbon steel feeder piping, that were also experiencing thinning, in the Point Lepreau Generating Station, primarily by an aggressive program of inspection, repair and testing of ex-service material. For the previous three maintenance outages, a probabilistic safety evaluation (PSE) had been used to demonstrate that annual inspection of the highest risk locations maintains the nuclear safety risk from cracking at an acceptably low level. The PSE makes use of the Failure Assessment Diagram (FAD) model to predict the failure of part-through-wall cracks. Burst-pressure testing of two ex-service feeder pipe sections with part-through-wall cracks showed that this FAD model significantly under predicts the failure pressure measured in the component tests. Use of this FAD model introduces undesirable conservatism into PSE assessments that are used to optimize feeder piping inspection and maintenance plans. This paper describes an alternative finite element approach, which could be used to provide more representative structural models for use in PSE assessments. This alternative approach employs the elasto-plastic large strain finite element formulation; uses representative material properties; considers the spatial microstructural distribution; accounts for the effect of work hardening rate; models all deformation processes, i.e., uniform deformation, localized necking, and failure imitation and propagation. Excellent pre-test prediction was shown for the burst-pressure test performed in 2006. Although cold-worked feeder bends have reduced fracture toughness compared to the parent straight pipe, post-test metallurgical examinations showed that failure at the

  1. Observing the continental-scale carbon balance: assessment of sampling complementarity and redundancy in a terrestrial assimilation system by means of quantitative network design

    OpenAIRE

    Kaminski, T.; Rayner, P. J.; Vossbeck, M.; Scholze, M.; Koffi, E.

    2012-01-01

    This paper investigates the relationship between the heterogeneity of the terrestrial carbon cycle and the optimal design of observing networks to constrain it. We combine the methods of quantitative network design and carbon-cycle data assimilation to a hierarchy of increasingly heterogeneous descriptions of the European terrestrial biosphere as indicated by increasing diversity of plant functional types. We employ three types of observat...

  2. Analysis of first and second law of an engine operating with bio diesel from palm oil. Part 1: global energy balance

    International Nuclear Information System (INIS)

    Agudelo, John R; Agudelo, Andres F; Cuadrado, Ilba G.

    2006-01-01

    A first law of thermodynamics analysis in a diesel engine operating with palm oil bio diesel and its blends with diesel fuel is presented. Measurements were carried out in a test bench under stationary conditions varying engine load at constant speed and vice versa. The variation in energy distribution, efficiency, performance and emissions were obtained under several operating points. It was found that fuel type do not affect energy distribution and effective efficiency. On the other hand, engine operating conditions have an important effect on energy balance and performance. CO 2 emissions didn't exhibit a clear tendency with bio diesel concentration in the blend. Nevertheless, O 2 concentration in exhaust gases exhibits a direct relationship with this concentration, independent of engine operating condition.

  3. Evaluation of paleovegetation changes in the northwest part of the Amazon region, Brazil: a carbon isotope approach in soils

    International Nuclear Information System (INIS)

    Gomes, B.M.; Pessenda, L.C.R.; Aravena, R.

    1995-01-01

    Full text. Numerous studies have focused on the understanding of the vegetation dynamics in the amazon region and its realtion to climate. The research approaches in these studies have involved the use of biological, geomorphologic and botanical tools, (1,2). Our approach involves the use of 13 and 14 C analyses in soil organic mater t infer past vegeation changes in the Amazon region (3). This is based on the distinct composition that characterize the C 3 and C 4 plants, that formed the different vegetation communities that exist in the Amazon region. 14 C used as a dating tool. This paper present data in soils collected in the Rondonia State, located in the northwestern part of the Amazon region. The soils were collected along a transect that include four distinct vegetation communities, ranging from a Cerrado type vegetation (southern part), dominated by C 4 grasses, to a tropical forest (northern part). The soils types are Latossolo Vermelho Amarelo at the Cerrado, Cerrado-transition and forest-transition sites, and Podzolico Vermelho amarelo at the forest site. 14 C data obtained in total soil organic matter, humin fraction and charcoal indicate that the organic matterin these soils is at least Holocene in age. The forest and the forest-transition sites area characterized by typical δ 13 C profiles (-29 to -24 0/00), indicating the predominance of C 3 plants during the past in this region. The Cerrado-transition sites show a significant change in δ 13 C from -27.5 0/00 at the surface to -19 0/00 at 30 cm. This value changed toward more depleted δ 13 C values at the 90-100 cm depth interval, reaching a value of -30 0/00 at 190-200 cm depth interval. This trend has to be associated to a change from a forest type vegetation (190-200 cm to 130-140 cm), to a vegetation community with a mayor influence of C 4 palnts recorded i the interval between 110-120 to 20-23 cm depth. The δ 13 C values at the Cerrado sites are the more enriched ones observed in this study

  4. To sink or burn? A discussion of the potential contributions of forests to greenhouse gas balances through storing carbon or providing biofuels

    International Nuclear Information System (INIS)

    Kirschbaum, M.U.F.

    2003-01-01

    Forests can affect net CO 2 emissions by increasing or decreasing the amount of stored carbon, or by supplying biofuels for power generation to substitute for fossil fuels. However, forests store the most carbon when they remain undisturbed and are allowed to grow to maturity, whereas using wood for bioenergy requires wood removal from forests, which reduces on-site carbon storage. Hence, it is difficult to manage a forest simultaneously for maximum carbon storage and supplying fuelwood. For developing optimal strategies for the use of vegetation sinks, it is necessary to consider the feedbacks via the inherent natural adjustments in the global carbon cycle. Increased atmospheric CO 2 currently provides a driving force for carbon uptake by natural carbon reservoirs, such as the world's oceans. When carbon is removed from the atmosphere and stored in biomass, it lowers the concentration gradient between the atmosphere and these other reservoirs. This reduces the subsequent inherent rate of CO 2 removal from the atmosphere. This means that transferring a quantity of CO 2 from the atmosphere to a biomass pool lowers the atmospheric concentration the most immediately after the initial removal, but subsequently, the atmospheric concentration trends back towards the values without biospheric removal. The optimal timing for the use of vegetation sinks therefore depends on a number of factors: the length of time over which forest growth can be maintained, whether biomass is used for energy generation and on the nature of the most detrimental aspects of climate-change impacts. Climate-change impacts related to the instantaneous effect of temperature are mitigated less by vegetation sinks than impacts that act via the cumulative effect of increased temperature. It also means that short-term carbon storage in temporary sinks is not generally beneficial in mitigating climate change

  5. Women's Work-Life Balance Trajectories in the UK: Reformulating Choice and Constraint in Transitions through Part-Time Work across the Life-Course

    Science.gov (United States)

    Tomlinson, Jennifer

    2006-01-01

    This paper examines the apparently paradoxical notion that women "choose" part-time work when it is consistently documented as being less preferential in employment terms, conditions and prospects when compared to full-time work. Forming a dialogue with Hakim's (2000) preference theory, it is proposed here that four dimensions--care…

  6. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S., Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Beverly E. Law

    2011-10-05

    As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance.

  7. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Warren [USDA Forest Service

    2014-07-03

    As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance.

  8. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part II: Mechanical modeling

    KAUST Repository

    Han, Fei; Azdoud, Yan; Lubineau, Gilles

    2014-01-01

    We present two modeling approaches for predicting the macroscopic elastic properties of carbon nanotubes/polymer composites with thick interphase regions at the nanotube/matrix frontier. The first model is based on local continuum mechanics

  9. Vapor Grown Carbon Fiber/Polydicyclopentadiene Composites: Shapeable Pastes to Make Composite Tooling and Plasma Erosion-Resistant Parts

    National Research Council Canada - National Science Library

    Pittman, Charles

    2002-01-01

    Vapor grown carbon nanofibers (VGCF) with 60-250nm diameters and 10 to 80 micrometers lengths were blended with the nonpolar organic monomer, dicyclopentadiene, to create liquid dispersions or pastes (based on the wt% fiber used...

  10. Tools to support GHG emissions reduction : a regional effort, part 1 - carbon footprint estimation and decision support.

    Science.gov (United States)

    2010-09-01

    Tools are proposed for carbon footprint estimation of transportation construction projects and decision support : for construction firms that must make equipment choice and usage decisions that affect profits, project duration : and greenhouse gas em...

  11. Temperature, salinity, nutrients, carbon, and other profile data collected worldwide as part of the CARINA project (NODC Accession 0057766)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CARINA (CARbon dioxide IN the Atlantic Ocean) data synthesis project is an international collaborative effort of the EU IP CARBOOCEAN, and US partners. It has...

  12. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part I: Micro-structural characterization and geometric modeling

    KAUST Repository

    Han, Fei

    2014-01-01

    A computational strategy to predict the elastic properties of carbon nanotube-reinforced polymer composites is proposed in this two-part paper. In Part I, the micro-structural characteristics of these nano-composites are discerned. These characteristics include networks/agglomerations of carbon nanotubes and thick polymer interphase regions between the nanotubes and the surrounding matrix. An algorithm is presented to construct three-dimensional geometric models with large amounts of randomly dispersed and aggregated nanotubes. The effects of the distribution of the nanotubes and the thickness of the interphase regions on the concentration of the interphase regions are demonstrated with numerical results. © 2013 Elsevier B.V. All rights reserved.

  13. The effectiveness of plug-in hybrid electric vehicles and renewable power in support of holistic environmental goals: Part 2 - Design and operation implications for load-balancing resources on the electric grid

    Science.gov (United States)

    Tarroja, Brian; Eichman, Joshua D.; Zhang, Li; Brown, Tim M.; Samuelsen, Scott

    2015-03-01

    A study has been performed that analyzes the effectiveness of utilizing plug-in vehicles to meet holistic environmental goals across the combined electricity and transportation sectors. In this study, plug-in hybrid electric vehicle (PHEV) penetration levels are varied from 0 to 60% and base renewable penetration levels are varied from 10 to 63%. The first part focused on the effect of installing plug-in hybrid electric vehicles on the environmental performance of the combined electricity and transportation sectors. The second part addresses impacts on the design and operation of load-balancing resources on the electric grid associated with fleet capacity factor, peaking and load-following generator capacity, efficiency, ramp rates, start-up events and the levelized cost of electricity. PHEVs using smart charging are found to counteract many of the disruptive impacts of intermittent renewable power on balancing generators for a wide range of renewable penetration levels, only becoming limited at high renewable penetration levels due to lack of flexibility and finite load size. This study highlights synergy between sustainability measures in the electric and transportation sectors and the importance of communicative dispatch of these vehicles.

  14. Getting the balance right

    International Nuclear Information System (INIS)

    1987-01-01

    This 8 page leaflet is published by the Nuclear Electricity Information Group (NEIG) which is made up of eight different bodies working within the nuclear industry. It aims to present a balanced outline of the facts needed to form an opinion about energy policy in the UK. It looks at the price of electricity, other sources of electricity, (oil and coal, solar power, wind power, water power), safety in the nuclear industry, nuclear waste disposal and risks from radiation. The NEIG is in favour of a balanced energy programme with nuclear energy being only a part of the overall scheme. (U.K.)

  15. Mechanisms of scale formation and carbon dioxide partial pressure influence. Part I. Elaboration of an experimental method and a scaling model.

    Science.gov (United States)

    Gal, Jean-Yves; Fovet, Yannick; Gache, Nathalie

    2002-02-01

    Scale formation in industrial or domestic installations is still an important economic problem. The existence of a metastable domain for calcium carbonate supersaturated solutions and its breakdown are observed under conditions rarely well defined. In most cases it is the pH rise caused by the carbon dioxide loss that involves calcium carbonate precipitation. Before studying this problem, we suggest in this first part, a new model for the evolution of the calcocarbonic system that takes into account the hydrated forms of CaCO3: CaCO3 amorphous, CaCO3 x 6H2O (ikaite) and CaCO3 x H2O (monohydrate). According to this model, the precipitation of any one of these hydrated forms could be responsible for the breakdown of the metastable state. After this first step, the solids evolve into dehydrated forms. At first, the metastable domain spread of the calcium carbonate supersaturated solutions was studied by the elaboration of computer programs in which the formation of CaCO3(0)(aq) ion pairs was taken into account. These ion pairs are supposed to evolve through dehydration to form the various calcium carbonate solid form precursors. This thermodynamic study was then compared to the experimental methods of the critical pH. Here the pH rise was caused by adding sodium hydroxide under different conditions for sodium hydroxide addition speed, agitation mode and ageing of solutions. For the highest speed of sodium hydroxide addition, the CaCO3 ionic product reached the value of the amorphous calcium carbonate solubility product, and the reaction of the amorphous calcium carbonate precipitation was of the homogenous type. Decreasing the reagent's addition speed caused an extension of the titration time. Then, the breakdown of the metastable state was obtained with the CaCO3 x H2O heterogeneous precipitation. This clearly illustrates the probable ageing of the precursors of the solid states that are considered in this model.

  16. Balance Disorders

    Science.gov (United States)

    ... vertigo. If you have additional problems with motor control, such as weakness, slowness, tremor, or rigidity, you can lose your ability to recover properly from imbalance. This raises the risk of falling and injury. What are some types of balance disorders? There are more than a dozen different ...

  17. Balancing Eggs

    Science.gov (United States)

    Mills, Allan

    2014-01-01

    Theory predicts that an egg-shaped body should rest in stable equilibrium when on its side, balance vertically in metastable equilibrium on its broad end and be completely unstable on its narrow end. A homogeneous solid egg made from wood, clay or plastic behaves in this way, but a real egg will not stand on either end. It is shown that this…

  18. Evaluating options for balancing the water–electricity nexus in California: Part 2—Greenhouse gas and renewable energy utilization impacts

    Energy Technology Data Exchange (ETDEWEB)

    Tarroja, Brian; AghaKouchak, Amir; Sobhani, Reza; Feldman, David; Jiang, Sunny; Samuelsen, Scott, E-mail: gss@uci.edu

    2014-11-01

    A study was conducted to compare the technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climate-change augmented inflow and demand conditions. Part 2 of the study focused on determining the greenhouse gas and renewable energy utilization impacts of different pathways to stabilize major surface reservoir levels. Using a detailed electric grid model and taking into account impacts on the operation of the water supply infrastructure, the greenhouse gas emissions and effect on overall grid renewable penetration level was calculated for each water supply option portfolio that successfully secured water availability from Part 1. The effects on the energy signature of water supply infrastructure were found to be just as important as that of the fundamental processes for each option. Under historical (baseline) conditions, many option portfolios were capable of securing surface reservoir levels with a net neutral or negative effect on emissions and a benefit for renewable energy utilization. Under climate change augmented conditions, however, careful selection of the water supply option portfolio was required to prevent imposing major emissions increases for the system. Overall, this analysis provided quantitative insight into the tradeoffs associated with choosing different pathways for securing California's water supply. - Highlights: • Part I presents a spatially and temporally resolved model of California’s surface reservoirs. • Part II presents GHG emissions and grid renewable penetration for water availability options. • In particular, the energy signature of water supply infrastructure is delineated. • Different pathways for securing California’s water supply are developed quantitatively. • Under baseline conditions, portfolios capable of securing surface reservoir levels emerge. • Under climate change conditions, the

  19. Evaluating options for balancing the water–electricity nexus in California: Part 2—Greenhouse gas and renewable energy utilization impacts

    International Nuclear Information System (INIS)

    Tarroja, Brian; AghaKouchak, Amir; Sobhani, Reza; Feldman, David; Jiang, Sunny; Samuelsen, Scott

    2014-01-01

    A study was conducted to compare the technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climate-change augmented inflow and demand conditions. Part 2 of the study focused on determining the greenhouse gas and renewable energy utilization impacts of different pathways to stabilize major surface reservoir levels. Using a detailed electric grid model and taking into account impacts on the operation of the water supply infrastructure, the greenhouse gas emissions and effect on overall grid renewable penetration level was calculated for each water supply option portfolio that successfully secured water availability from Part 1. The effects on the energy signature of water supply infrastructure were found to be just as important as that of the fundamental processes for each option. Under historical (baseline) conditions, many option portfolios were capable of securing surface reservoir levels with a net neutral or negative effect on emissions and a benefit for renewable energy utilization. Under climate change augmented conditions, however, careful selection of the water supply option portfolio was required to prevent imposing major emissions increases for the system. Overall, this analysis provided quantitative insight into the tradeoffs associated with choosing different pathways for securing California's water supply. - Highlights: • Part I presents a spatially and temporally resolved model of California’s surface reservoirs. • Part II presents GHG emissions and grid renewable penetration for water availability options. • In particular, the energy signature of water supply infrastructure is delineated. • Different pathways for securing California’s water supply are developed quantitatively. • Under baseline conditions, portfolios capable of securing surface reservoir levels emerge. • Under climate change conditions, the

  20. The energy balance experiment EBEX-2000. Part II: Intercomparison of eddy-covariance sensors and post-field data processing methods

    Science.gov (United States)

    Mauder, Matthias; Oncley, Steven P.; Vogt, Roland; Weidinger, Tamas; Ribeiro, Luis; Bernhofer, Christian; Foken, Thomas; Kohsiek, Wim; de Bruin, Henk A. R.; Liu, Heping

    2007-04-01

    The eddy-covariance method is the primary way of measuring turbulent fluxes directly. Many investigators have found that these flux measurements often do not satisfy a fundamental criterion—closure of the surface energy balance. This study investigates to what extent the eddy-covariance measurement technology can be made responsible for this deficiency, in particular the effects of instrumentation or of the post-field data processing. Therefore, current eddy-covariance sensors and several post-field data processing methods were compared. The differences in methodology resulted in deviations of 10% for the sensible heat flux and of 15% for the latent heat flux for an averaging time of 30 min. These disparities were mostly due to different sensor separation corrections and a linear detrending of the data. The impact of different instrumentation on the resulting heat flux estimates was significantly higher. Large deviations from the reference system of up to 50% were found for some sensor combinations. However, very good measurement quality was found for a CSAT3 sonic together with a KH20 krypton hygrometer and also for a UW sonic together with a KH20. If these systems are well calibrated and maintained, an accuracy of better than 5% can be achieved for 30-min values of sensible and latent heat flux measurements. The results from the sonic anemometers Gill Solent-HS, ATI-K, Metek USA-1, and R.M. Young 81000 showed more or less larger deviations from the reference system. The LI-COR LI-7500 open-path H2O/CO2 gas analyser in the test was one of the first serial numbers of this sensor type and had technical problems regarding direct solar radiation sensitivity and signal delay. These problems are known by the manufacturer and improvements of the sensor have since been made.

  1. Energy balance in the transformation centers

    International Nuclear Information System (INIS)

    Alvim, Carlos Feu; Ferreira, Omar Campos; Eidelman, Frida.

    2005-01-01

    Carbon balance is an important instrument to identify the emission sources of greenhouse effect gases. Since energy use and transformation are fundamental for increasing these gases in the atmosphere, the carbon balance survey can be used to identify sectors and fuels to which priority should be given regarding emissions mitigation. In the case of transformation centers (installations where primary or secondary sources are converted into sub-products or other energy form) the balance indicated some problems regarding the Brazilian inventory calculation. Problems concerning the National Energy Balance data used here were also identified. (author)

  2. [Variation of forest vegetation carbon storage and carbon sequestration rate in Liaoning Province, Northeast China].

    Science.gov (United States)

    Zhen, Wei; Huang, Mei; Zhai, Yin-Li; Chen, Ke; Gong, Ya-Zhen

    2014-05-01

    The forest vegetation carbon stock and carbon sequestration rate in Liaoning Province, Northeast China, were predicted by using Canadian carbon balance model (CBM-CFS3) combining with the forest resource data. The future spatio-temporal distribution and trends of vegetation carbon storage, carbon density and carbon sequestration rate were projected, based on the two scenarios, i. e. with or without afforestation. The result suggested that the total forest vegetation carbon storage and carbon density in Liaoning Province in 2005 were 133.94 Tg and 25.08 t x hm(-2), respectively. The vegetation carbon storage in Quercus was the biggest, while in Robinia pseudoacacia was the least. Both Larix olgensis and broad-leaved forests had higher vegetation carbon densities than others, and the vegetation carbon densities of Pinus tabuliformis, Quercus and Robinia pseudoacacia were close to each other. The spatial distribution of forest vegetation carbon density in Liaoning Province showed a decrease trend from east to west. In the eastern forest area, the future increase of vegetation carbon density would be smaller than those in the northern forest area, because most of the forests in the former part were matured or over matured, while most of the forests in the later part were young. Under the scenario of no afforestation, the future increment of total forest vegetation carbon stock in Liaoning Province would increase gradually, and the total carbon sequestration rate would decrease, while they would both increase significantly under the afforestation scenario. Therefore, afforestation plays an important role in increasing vegetation carbon storage, carbon density and carbon sequestration rate.

  3. Balanced articulated manipulator

    International Nuclear Information System (INIS)

    Francois, Daniel; Germond, J.-C.; Marchal, Paul; Vertut, Jean.

    1976-01-01

    The description is given of a manipulator of the type comprising a master arm and a slave arm, capable of working in a containment restricted by a wall fitted with an aperture to introduce the slave arm into the containment. According to the invention this manipulator is permanently balanced irrespective of its distortions when it is secured to the wall of the containment in which it is desired to work. The entire manipulator is also balanced when being set up and when moved outside the containment, in relation to a supporting axle. This result is achieved in a simplified manner by giving homothetic shapes to the various component parts of the slave and master arms, the master arm having at least one balancing weight [fr

  4. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L. Biochar and Feasibility for Carbon Capture and Energy Balance.

    Directory of Open Access Journals (Sweden)

    Muhammad Khalid Rafiq

    Full Text Available This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13. Higher heating value (HHV of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13 demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  5. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  6. Foreseen hydrological changes drive efforts to formulate water balance improvement measures as part of the management options of adaptation at Lake Balaton, Hungary

    Science.gov (United States)

    Molnar, Gabor; Kutics, Karoly

    2013-04-01

    completed with a similar methodology applied in partner lakes of the EULAKES project. Based on the assessment through a participatory process involving a broad group of stakeholders the possible management options were gathered and tested as the alternatives to improve the water balance of the lake.

  7. Modelling Behaviour of a Carbon Epoxy Composite Exposed to Fire: Part II-Comparison with Experimental Results.

    Science.gov (United States)

    Tranchard, Pauline; Samyn, Fabienne; Duquesne, Sophie; Estèbe, Bruno; Bourbigot, Serge

    2017-04-28

    Based on a phenomenological methodology, a three dimensional (3D) thermochemical model was developed to predict the temperature profile, the mass loss and the decomposition front of a carbon-reinforced epoxy composite laminate (T700/M21 composite) exposed to fire conditions. This 3D model takes into account the energy accumulation by the solid material, the anisotropic heat conduction, the thermal decomposition of the material, the gas mass flow into the composite, and the internal pressure. Thermophysical properties defined as temperature dependant properties were characterised using existing as well as innovative methodologies in order to use them as inputs into our physical model. The 3D thermochemical model accurately predicts the measured mass loss and observed decomposition front when the carbon fibre/epoxy composite is directly impacted by a propane flame. In short, the model shows its capability to predict the fire behaviour of a carbon fibre reinforced composite for fire safety engineering.

  8. Description, calibration and sensitivity analysis of the local ecosystem submodel of a global model of carbon and nitrogen cycling and the water balance in the terrestrial biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kercher, J.R. [Lawrence Livermore National Lab., CA (United States); Chambers, J.Q. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Santa Barbara, CA (United States). Dept. of Biological Sciences

    1995-10-01

    We have developed a geographically-distributed ecosystem model for the carbon, nitrogen, and water dynamics of the terrestrial biosphere TERRA. The local ecosystem model of TERRA consists of coupled, modified versions of TEM and DAYTRANS. The ecosystem model in each grid cell calculates water fluxes of evaporation, transpiration, and runoff; carbon fluxes of gross primary productivity, litterfall, and plant and soil respiration; and nitrogen fluxes of vegetation uptake, litterfall, mineralization, immobilization, and system loss. The state variables are soil water content; carbon in live vegetation; carbon in soil; nitrogen in live vegetation; organic nitrogen in soil and fitter; available inorganic nitrogen aggregating nitrites, nitrates, and ammonia; and a variable for allocation. Carbon and nitrogen dynamics are calibrated to specific sites in 17 vegetation types. Eight parameters are determined during calibration for each of the 17 vegetation types. At calibration, the annual average values of carbon in vegetation C, show site differences that derive from the vegetation-type specific parameters and intersite variation in climate and soils. From calibration, we recover the average C{sub v} of forests, woodlands, savannas, grasslands, shrublands, and tundra that were used to develop the model initially. The timing of the phases of the annual variation is driven by temperature and light in the high latitude and moist temperate zones. The dry temperate zones are driven by temperature, precipitation, and light. In the tropics, precipitation is the key variable in annual variation. The seasonal responses are even more clearly demonstrated in net primary production and show the same controlling factors.

  9. Evaluation of Net Primary Productivity and Carbon Allocation to Different Parts of Corn in Different Tillage and Nutrient Management Systems

    Directory of Open Access Journals (Sweden)

    esmat mohammadi

    2017-09-01

    Full Text Available Evaluation of net primary productivity and carbon allocation to different organs of corn under nutrient management and tillage systems Introduction Agriculture operations produce 10 to 20 percent of greenhouse gases. As a result of conventional operations of agriculture, greenhouse gases have been increased (Osborne et al., 2010. Therefor it is necessary to notice to carbon sequestration to reduce greenhouse gases emissions. In photosynthesis process, plants absorb CO2 and large amounts of organic carbon accumulate in their organs. Biochar is produced of pyrolysis of organic compounds. Biochar is an appropriate compound for improved of soil properties and carbon sequestration (Whitman and Lehmann, 2009; Smith et al., 2010. Conservation tillage has become an important technology in sustainable agriculture due to its benefits. So the aim of this study was to evaluate the effect of nutrient management and tillage systems on net primary production and carbon allocation to different organs of corn in Shahrood. Material and methods This study was conducted at the Shahrood University of Technology research farm. Experiment was done as split plot in randomized complete block design with three replications. Tillage systems with two levels (conventional tillage and minimum tillage were as the main factor and nutrient management in seven levels including (control, chemical fertilizer, manure, biochar, chemical fertilizer + manure, chemical fertilizer + biochar, manure + biochar were considered as sub plot. At the time of maturity of corn, was sampled from its aboveground and belowground biomasses. Carbon content of shoot, seed and root was considered almost 45 percent of yield of each of these biomasses and carbon in root exudates almost 65 percent of carbon in the root. Statistical analysis of the data was performed using SAS program. Comparison of means was conducted with LSD test at the 5% level. Results and discussion Effect of nutrient management was

  10. Silurian and Devonian source rocks and crude oils from the western part of Libya: Organic geochemistry, palynology and carbon stratigraphy

    NARCIS (Netherlands)

    Elkelani, Mohamed M.A.

    2015-01-01

    The Early Silurian “hot” shales and Late Devonian black shales are major regional oil and gas source rocks in North Africa. Their deposition probably played a major role in global carbon cycling in general because of the large areas of the ocean affected. Comparing the Libyan δ13C record with

  11. Chemical processes of coal for use in power plants. Part 1: Approximate analysis and associated indexes of pulverized coal; Procesos quimicos del carbon para su uso en centrales termoelectricas. Parte 1: Analisis aproximado e indices asociados del carbon pulverizado

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Bedolla, J. A.; Manzanares-Papayanopoulos, E.; Herrera-Velarde, J. R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: emp@iie.org.mx

    2010-11-15

    The usage of hydrocarbons, such as natural gas, oil products and coal, will be the main source of energy to the mankind for next generations. Therefore, the actual research and technological developments point out to employ with high efficiency those fuels. The main interests are to release most of the energy as possible and to guide the combustion reactions. It is well known that during the combustion process of coal, the chemical energy is converted to thermal energy, which it allows the steam production, and therefore to produce energy through an electric generator. The main interest of the work presented here is to study the behavior of the coal combustion processes in function of the approximate analysis and some associate indices of that analysis, to point out the optimization of the coal usage as main fuel in electrical power generation plants. [Spanish] El uso de hidrocarburos como son el gas natural, los derivados del petroleo y el carbon mineral, continuara siendo en las proximas decadas la principal fuente de energia de la humanidad. Por consiguiente, la investigacion cientifica y los desarrollos tecnologicos actualmente se enfocan en emplear de manera mas eficiente dichos combustibles, satisfaciendo entre otros factores, dos intereses principales: liberar la mayor cantidad de energia, reduciendo al minimo el material combustible no quemado, y direccionar las reacciones del proceso de combustion para minimizar la cantidad de productos no deseados resultantes de la reaccion. A traves de los procesos quimicos de combustion del carbon, se transforma la energia quimica a energia termica, lo que permite la produccion de vapor para a su vez impulsar una turbina la cual esta acoplada a un generador electrico. El objetivo del presente trabajo es el estudio del comportamiento de los procesos quimicos que se llevan a cabo durante las reacciones de combus-tion del carbon en funcion del analisis aproximado y de los indices asociados resultantes de dicho analisis; lo

  12. Application of processing maps in the optimization of the parameters of a hot working process. Part 2. Processing maps of a microalloyed medium carbon steel

    International Nuclear Information System (INIS)

    Al Omar, A.; Cabrera, J.M.; Prado, J.M.

    1997-01-01

    Part 1 of this work presents a revision of the general characteristics of the so called dynamic materials model on which processing maps are developed. In this part following the methodology described in part 1, processing maps of a microalloyed medium carbon steel are developed over a temperature range varying from 900 to 1.150 degree centigree at different true strain rates ranging from 10''-4 to 10s''-1. The analysis of these maps revealed a domain of dynamic recrystallization centred at about 1.1.50 degree centigree and strain rate 10 s''-1 and a domain of dynamic recovery centred at 900 degree centigree and 0,1 s''-1. (Author) 20 refs

  13. Towards complete and harmonized assessment of soil carbon stocks and balance in forests: The ability of the Yasso07 model across a wide gradient of climatic and forest conditions in Europe.

    Science.gov (United States)

    Hernández, Laura; Jandl, Robert; Blujdea, Viorel N B; Lehtonen, Aleksi; Kriiska, Kaie; Alberdi, Iciar; Adermann, Veiko; Cañellas, Isabel; Marin, Gheorghe; Moreno-Fernández, Daniel; Ostonen, Ivika; Varik, Mats; Didion, Markus

    2017-12-01

    Accurate carbon-balance accounting in forest soils is necessary for the development of climate change policy. However, changes in soil organic carbon (SOC) occur slowly and these changes may not be captured through repeated soil inventories. Simulation models may be used as alternatives to SOC measurement. The Yasso07 model presents a suitable alternative because most of the data required for the application are readily available in countries with common forest surveys. In this study, we test the suitability of Yasso07 for simulating SOC stocks and stock changes in a variety of European forests affected by different climatic, land use and forest management conditions and we address country-specific cases with differing resources and data availability. The simulated SOC stocks differed only slightly from measured data, providing realistic, reasonable mean SOC estimations per region or forest type. The change in the soil carbon pool over time, which is the target parameter for SOC reporting, was generally found to be plausible although not in the case of Mediterranean forest soils. As expected under stable forest management conditions, both land cover and climate play major roles in determining the SOC stock in forest soils. Greater mean SOC stocks were observed in northern latitudes (or at higher altitude) than in southern latitudes (or plains) and conifer forests were found to store a notably higher amount of SOC than broadleaf forests. Furthermore, as regards change in SOC, an inter-annual sink effect was identified for most of the European forest types studied. Our findings corroborate the suitability of Yasso07 to assess the impact of forest management and land use change on the SOC balance of forests soils, as well as to accurately simulate SOC in dead organic matter (DOM) and mineral soil pools separately. The obstacles encountered when applying the Yasso07 model reflect a lack of available input data. Future research should focus on improving our knowledge of

  14. A multi-level simulation platform of natural gas internal reforming solid oxide fuel cell-gas turbine hybrid generation system - Part II. Balancing units model library and system simulation

    Science.gov (United States)

    Bao, Cheng; Cai, Ningsheng; Croiset, Eric

    2011-10-01

    Following our integrated hierarchical modeling framework of natural gas internal reforming solid oxide fuel cell (IRSOFC), this paper firstly introduces the model libraries of main balancing units, including some state-of-the-art achievements and our specific work. Based on gPROMS programming code, flexible configuration and modular design are fully realized by specifying graphically all unit models in each level. Via comparison with the steady-state experimental data of Siemens-Westinghouse demonstration system, the in-house multi-level SOFC-gas turbine (GT) simulation platform is validated to be more accurate than the advanced power system analysis tool (APSAT). Moreover, some units of the demonstration system are designed reversely for analysis of a typically part-load transient process. The framework of distributed and dynamic modeling in most of units is significant for the development of control strategies in the future.

  15. Using Multiple Linear Regression Techniques to Quantify Carbon ...

    African Journals Online (AJOL)

    komla

    Process and statistical models of productivity, though useful, are often ... The carbon balance of terrestrial ecosystems is uncertain, in part due to discrepancies and errors in .... The ecological data were collected through field work to include both .... Computer-aided Multivariate Analysis, Life Learning Publications, Belmont,.

  16. Balancing Risk

    DEFF Research Database (Denmark)

    Nygaard, Lene; Rossen, Camilla Blach; Buus, Niels

    2015-01-01

    This study explored how eight pregnant women diagnosed with depression managed the decision whether or not to take antidepressants during pregnancy. In total, 11 interviews were conducted and analysed by means of constructivist grounded theory. The major category constructed was Balancing risk......, with two minor categories: Assessing depression and antidepressants and Evaluating the impact of significant others. The participants tried to make the safest decision, taking all aspects of their life into consideration. They described successful decision-making in the context of managing social norms...

  17. Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project – Part 1: calibration, urban enhancements, and uncertainty estimates

    Directory of Open Access Journals (Sweden)

    K. R. Verhulst

    2017-07-01

    Full Text Available We report continuous surface observations of carbon dioxide (CO2 and methane (CH4 from the Los Angeles (LA Megacity Carbon Project during 2015. We devised a calibration strategy, methods for selection of background air masses, calculation of urban enhancements, and a detailed algorithm for estimating uncertainties in urban-scale CO2 and CH4 measurements. These methods are essential for understanding carbon fluxes from the LA megacity and other complex urban environments globally. We estimate background mole fractions entering LA using observations from four extra-urban sites including two marine sites located south of LA in La Jolla (LJO and offshore on San Clemente Island (SCI, one continental site located in Victorville (VIC, in the high desert northeast of LA, and one continental/mid-troposphere site located on Mount Wilson (MWO in the San Gabriel Mountains. We find that a local marine background can be established to within  ∼  1 ppm CO2 and  ∼  10 ppb CH4 using these local measurement sites. Overall, atmospheric carbon dioxide and methane levels are highly variable across Los Angeles. Urban and suburban sites show moderate to large CO2 and CH4 enhancements relative to a marine background estimate. The USC (University of Southern California site near downtown LA exhibits median hourly enhancements of  ∼  20 ppm CO2 and  ∼  150 ppb CH4 during 2015 as well as  ∼  15 ppm CO2 and  ∼  80 ppb CH4 during mid-afternoon hours (12:00–16:00 LT, local time, which is the typical period of focus for flux inversions. The estimated measurement uncertainty is typically better than 0.1 ppm CO2 and 1 ppb CH4 based on the repeated standard gas measurements from the LA sites during the last 2 years, similar to Andrews et al. (2014. The largest component of the measurement uncertainty is due to the single-point calibration method; however, the uncertainty in the background mole fraction is much

  18. Balanço de carbono e nutrientes em plantio puro e misto de espécies florestais nativas no sudeste da Bahia Carbon and nutrient balance in pure and mixed stands of native tree species in Southeastern Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Carlos da Gama-Rodrigues

    2008-06-01

    Full Text Available A manutenção da produção florestal depende da quantidade e do fluxo de nutrientes no ecossistema, os quais são afetados pelas técnicas de manejo utilizadas. O objetivo deste trabalho foi avaliar diferenças na ciclagem e no balanço de C e nutrientes, em plantio puro e misto de espécies florestais nativas, bem como em fragmentos florestais de Mata Atlântica. O trabalho foi desenvolvido em solos de tabuleiro do sudeste da Bahia, Brasil, no período de agosto de 1994 a julho de 1995, em plantios, com 22 anos de idade, de pau-roxo, Peltogyne angustiflora; putumuju, Centrolobium robustum; arapati, Arapatiella psilophylla; arapaçu, Sclerolobium chrysophyllum; claraíba, Cordia trichotoma; e óleo-comumbá, Macrolobium latifolium. Como referências, foram utilizadas uma floresta secundária, praticamente em estado clímax, e uma capoeira de 40 anos de idade. As quantidades totais de carbono e nutrientes no sistema (solo + parte aérea + serapilheira variou marcadamente entre as espécies florestais. O plantio misto apresentou maior acúmulo desses elementos do que os plantios puros. O plantio misto apresentou maior intensidade de ciclagem bioquímica para todos os nutrientes do que a média dos plantios puros. Resultado similar ocorreu para a ciclagem biogeoquímica, à exceção de Ca. O balanço de C, P e K foi negativo em todas as coberturas florestais; entretanto, para N o balanço foi positivo. O balanço de Ca foi positivo apenas para o arapaçu, enquanto o de Mg foi negativo somente no putumuju e óleo-comumbá. O balanço mais negativo foi de P, seguido de K e Ca. O plantio misto apresentou balanço próximo à média dos plantios puros. Desse modo, o plantio misto mostrou-se mais adequado, por proporcionar, simultaneamente, maior eficiência da ciclagem bioquímica e biogeoquímica e balanços mais equilibrados de carbono e nutrientes.This study aimed to evaluate the differences in carbon and nutrient cycling and balance in two

  19. [Black carbon content and distribution in different particle size fractions of forest soils in the middle part of Great Xing'an Mountains, China.

    Science.gov (United States)

    Xu, Jia Hui; Gao, Lei; Cui, Xiao Yang

    2017-10-01

    Soil black carbon (BC) is considered to be the main component of passive C pool because of its inherent biochemical recalcitrance. In this paper, soil BC in the middle part of Great Xing'an Mountains was quantified, the distribution of BC in different particle size fractions was analyzed, and BC stabilization mechanism and its important role in soil C pool were discussed. The results showed that BC expressed obvious accumulation in surface soil, accounting for about 68.7% in the whole horizon (64 cm), and then decreased with the increasing soil depth, however, BC/OC showed an opposite pattern. Climate conditions redistributed BC in study area, and the soil under cooler and moister conditions would sequester more BC. BC proportion in different particle size fractions was in the order of clay>silt>fine sand>coarse sand. Although BC content in clay was the highest and was enhanced with increasing soil depth, BC/OC in clay did not show a marked change. Thus, the rise of BC/OC was attributed to the preservation of BC particles in the fine sand and silt fractions. Biochemical recalcitrance was the main stabilization mechanism for surface BC, and with the increasing soil depth, the chemical protection from clay mineral gradually played a predominant role. BC not only was the essential component of soil stable carbon pool, but also took up a sizable proportion in particulate organic carbon pool. Therefore, the storage of soil stable carbon and the potential of soil carbon sequestration would be enhanced owing to the existence of BC.

  20. Watt and joule balances

    Science.gov (United States)

    Robinson, Ian A.

    2014-04-01

    time of the weighing and at the centre of gravity of the mass. The paper by Liard and his co-authors at NRC describes how they have made this essential measurement. The accuracy of the watt balance may also depend on the alignment of the apparatus. Two papers deal with this important issue. The first, by Sanchez and his co-authors at NRC, shows that their balance is insensitive to a range of alignments and concentrates on the essential alignments that contribute directly to the overall uncertainty of the apparatus. Thomas and his co-authors at LNE describe their technique for reducing uncertainties in their watt balance by aligning its coil in the field of the magnet to minimize both horizontal forces and torques about horizontal axes. The search for discrepancies between the results from watt balances has encouraged researchers to consider possible error mechanisms arising from the secondary electrical interactions between the coil of a watt balance and other parts of the apparatus. Researchers from INRIM have two such papers: one considering magnetic interactions and the other considering electrostatic interactions. It is essential that such investigations are carried out: both to prove that the problems are understood and for the guidance of those building the next generation of watt and joule balances. The next four papers describe aspects of the construction of watt balances. The BIPM watt balance group describe the principles behind their simultaneous measurement scheme for a watt balance. The balance that they are constructing can also be used in the conventional two-phase mode and their paper describes the relative advantages and disadvantages of the two modes of operation. In a watt balance there are some advantages to precise vertical movement of the coil. The METAS group describe the two mechanisms that they have tested to achieve such motion and give the reasons for the choice of mechanism for use in the balance that they are constructing. The KRISS watt

  1. GFDL's ESM2 global coupled climate-carbon Earth System Models. Part I: physical formulation and baseline simulation characteristics

    Science.gov (United States)

    Dunne, John P.; John, Jasmin G.; Adcroft, Alistair J.; Griffies, Stephen M.; Hallberg, Robert W.; Shevalikova, Elena; Stouffer, Ronald J.; Cooke, William; Dunne, Krista A.; Harrison, Matthew J.; Krasting, John P.; Malyshev, Sergey L.; Milly, P.C.D.; Phillipps, Peter J.; Sentman, Lori A.; Samuels, Bonita L.; Spelman, Michael J.; Winton, Michael; Wittenberg, Andrew T.; Zadeh, Niki

    2012-01-01

    We describe the physical climate formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models, ESM2M and ESM2G. These models demonstrate similar climate fidelity as the Geophysical Fluid Dynamics Laboratory's previous CM2.1 climate model while incorporating explicit and consistent carbon dynamics. The two models differ exclusively in the physical ocean component; ESM2M uses Modular Ocean Model version 4.1 with vertical pressure layers while ESM2G uses Generalized Ocean Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the ocean mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of ocean dynamics on climate variability is highlighted in the El Niño-Southern Oscillation being overly strong in ESM2M and overly weak ESM2G relative to observations. Thus, while ESM2G might better represent climate changes relating to: total heat content variability given its lack of long term drift, gyre circulation and ventilation in the North Pacific, tropical Atlantic and Indian Oceans, and depth structure in the overturning and abyssal flows, ESM2M might better represent climate changes relating to: surface circulation given its superior surface temperature, salinity and height patterns, tropical Pacific circulation and variability, and Southern Ocean dynamics. Our overall assessment is that neither model is fundamentally superior to the other, and that both models achieve sufficient fidelity to allow meaningful climate and earth system modeling applications. This affords us the ability to assess the role of ocean configuration on earth system interactions in the context of two state-of-the-art coupled carbon-climate