WorldWideScience

Sample records for carbon sinks

  1. Forests as carbon sinks

    Energy Technology Data Exchange (ETDEWEB)

    Houghton, R.A.; Woodwell, R.M. [Woods Hole Research Center, Woods Hole, MA (United States)

    1995-11-01

    When the nations of the world signed and later ratified the United Nations Framework Convention on Climate Change (FCCC), they accepted the difficult challenge of stabilizing the composition of the atmosphere with respect to the greenhouse gases (GHGs). Success will require a reduction in both use of fossil fuels and rates of deforestation. Forests have a large enough influence on the atmosphere that one of the options for stabilizing the concentrations of GHGs in the atmosphere includes the use of forests as a carbon sink through reforestation of large areas. We identify in this paper the potential and the limitations of such projects. We discuss the implications of four approaches in management of forests globally: (i) continued deforestation, (ii) halting deforestation, (iii) net reforestation including agroforestry, and (iv) substituting the use of wood fuels for fossil fuels.

  2. Carbon sinks in temperate forests

    NARCIS (Netherlands)

    Martin, P.H.; Nabuurs, G.J.; Aubinet, M.; Karjalainen, T.; Vine, E.L.; Kinsman, J.; Heath, L.S.

    2001-01-01

    In addition to being scientifically exciting, commercially important, and environmentally essential, temperate forests have also become a key diplomatic item in international climate negotiations as potential sinks for carbon. This review presents the methods used to estimate carbon sequestration, i

  3. Rangelands: a closing carbon sink?

    Science.gov (United States)

    Kuhn, Nikolaus J.

    2016-04-01

    Two thirds of the world's agricultural land is suitable for grazing only. Much of this land has experienced severe erosion due to mismanagement, massive redistribution of soil and sediment, and significant degradation of vegetation. As a consequence, geochemical cycles have changed. Unlike croplands, the impact of degradation on nutrient fluxes is hardly compensated on rangelands, potentially disturbing the carbon cycle because of the declining biomass production and the subsequent conversion of litter into soil organic matter. Over time, the degradation leads to a decline in soil C stocks and, if associated with soil erosion, also to a decline in carbon transfer from soil into sediment sinks. A priory reasoning suggests that during the degradation process, with soil productivity not yet massively affected, the Carbon transfer initially increases because soil erosion rates are also greater than in the non-disturbed system. With most soil degradation in rangelands occurring during the past 200 years, this mechanism on a large part of the global land area could have generated an unintentional terrestrial carbon sink during a time period with increasing industrial CO2 emissions. Using global data on soil degradation, soil erosion, soil carbon stocks and dynamics to simulate their interaction and potential role for rangeland carbon cycles supports the assumption that rangelands may have functioned as a carbon sink, but reveals major uncertainties with regards to the size. This highlights the need to improve our knowledge and understanding of rangeland erosion, landscape change and soil formation, both with regards to the recent past, but also the impacts of their future use and climate.

  4. Territorial Rights and Carbon Sinks.

    Science.gov (United States)

    Vanderheiden, Steve

    2016-11-29

    Scholars concerned with abuses of the "resource privilege" by the governments of developing states sometimes call for national sovereignty over the natural resources that lie within its borders. While such claims may resist a key driver of the "resource curse" when applied to mineral resources in the ground, and are often recognized as among a people's territorial rights, their implications differ in the context of climate change, where they are invoked on behalf of a right to extract and combust fossil fuels that is set in opposition to global climate change mitigation imperatives. Moreover, granting full national sovereignty over territorial carbon sinks may conflict with commitments to equity in the sharing of national mitigation burdens, since much of the planet's carbon sink capacity lies within territorial borders to which peoples have widely disparate access. In this paper, I shall explore this tension between a global justice principle that is often applied to mineral resources and its tension with contrary principles that are often applied to carbon sink access, developing an analysis that seeks to reconcile what would otherwise appear to be fundamentally incompatible aims.

  5. Long-term decline of Amazon carbon the sink

    NARCIS (Netherlands)

    Brienen, R.J.W.; Phillips, O.L.; Feldpausch, T.; Gloor, E.; Baker, T.R.; Arets, E.J.M.M.; Pena Claros, M.; Poorter, L.

    2015-01-01

    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades1, 2, with a substantial fraction of this sink probably located in the tropics3, particularly in the Amazon4. Nevertheless, it is unclear how the terrestrial carbon sink will

  6. CARBOOCEAN -marine carbon sources and sinks assessment

    Science.gov (United States)

    Volbers, A.; Heinze, C.; de Baar, H.; CARBOOCEAN Consortium

    2009-04-01

    CARBOOCEAN is the European contribution to the global observation and modelling network on marine carbon. It is an FP6 Integrated Project funded over a five year period (2005-2009) with 14.5 million € and combines the key European experts of 35 contracting partners from 14 countries, including the USA. The project provides a description and quantification of the CO2 air-sea exchange ranging from a seasonal to interannual time scale up to a decadal to centennial time scale for the Atlantic Ocean and the Southern Ocean, involving also the sub-surface and deep waters. Special focus is given to the quantification of carbon sources and sinks at a regional scale and the identification and understanding of biogeochemical feedback mechanisms which control marine carbon uptake and release. The new data and knowledge is integrated into the prognostic modeling framework. One of the project highlights is the North Atlantic Observing Network which employs voluntary observing ships (VOS). The Air-sea fluxes of CO2 show a high temporal and spatial variation as a result of variability in climate, biological activity and ocean circulation. Latest data indicate that the North Atlantic and Southern Ocean both show at least transient decrease in uptake strength for CO2. The anthropogenic carbon uptake by the oceans is dominated by physical-chemical buffering but biological and biogeochemical effects cannot be neglected. Findings from data analysis, forward and inverse modeling indicate that the oceanic water column burden of anthropogenic carbon has a maximum in the northern North Atlantic close to the areas of deep convection but also the Southern Ocean carries significant amounts of anthropogenic carbon. These carbon sink areas of vertical water mass transfer are vulnerable to climate change.

  7. Do grasslands act as a perpetual sink for carbon?

    Science.gov (United States)

    Smith, Pete

    2014-09-01

    It is increasingly commonly suggested that grasslands are a perpetual sink for carbon, and that just maintaining grasslands will yield a net carbon sink. I examine the evidence for this from repeated soil surveys, long term grassland experiments and simple mass balance calculations. I conclude that it is untenable that grasslands act as a perpetual carbon sink, and the most likely explanation for observed grassland carbon sinks over short periods is legacy effects of land use and land management prior to the beginning of flux measurement periods. Simply having grassland does not result is a carbon sink, but judicious management or previously poorly managed grasslands can increase the sink capacity. Given that grasslands are a large store of carbon, and that it is easier and faster for soils to lose carbon that it is for them to gain carbon, it is an important management target to maintain these stocks.

  8. Biological control of the terrestrial carbon sink

    Science.gov (United States)

    Schulze, E.-D.

    2006-03-01

    different reasons depending on the region of the world: anthropogenic nitrogen deposition is the controlling factor in Europe, increasing global temperatures is the main factor in Siberia, and maybe rising CO2 the factor controlling the carbon fluxes in Amazonia. However, this has not lead to increases in net biome productivity, due to associated losses. Also important is the interaction between biodiversity and biogeochemical processes. It is shown that net primary productivity increases with plant species diversity (50% species loss equals 20% loss in productivity). However, in this extrapolation the action of soil biota is poorly understood although soils contribute the largest number of species and of taxonomic groups to an ecosystem. The global terrestrial carbon budget strongly depends on areas with pristine old growth forests which are carbon sinks. The management options are very limited, mostly short term, and usually associated with high uncertainty. Unmanaged grasslands appear to be a carbon sink of similar magnitude as forest, but generally these ecosystems lost their C with grazing and agricultural use. Extrapolation to the future of Earth climate shows that the biota will not be able to balance fossil fuel emissions, and that it will be essential to develop a carbon free energy system in order to maintain the living conditions on earth.

  9. Biological control of the terrestrial carbon sink

    Directory of Open Access Journals (Sweden)

    E.-D. Schulze

    2006-01-01

    plant growth has different reasons depending on the region of the world: anthropogenic nitrogen deposition is the controlling factor in Europe, increasing global temperatures is the main factor in Siberia, and maybe rising CO2 the factor controlling the carbon fluxes in Amazonia. However, this has not lead to increases in net biome productivity, due to associated losses. Also important is the interaction between biodiversity and biogeochemical processes. It is shown that net primary productivity increases with plant species diversity (50% species loss equals 20% loss in productivity. However, in this extrapolation the action of soil biota is poorly understood although soils contribute the largest number of species and of taxonomic groups to an ecosystem. The global terrestrial carbon budget strongly depends on areas with pristine old growth forests which are carbon sinks. The management options are very limited, mostly short term, and usually associated with high uncertainty. Unmanaged grasslands appear to be a carbon sink of similar magnitude as forest, but generally these ecosystems lost their C with grazing and agricultural use. Extrapolation to the future of Earth climate shows that the biota will not be able to balance fossil fuel emissions, and that it will be essential to develop a carbon free energy system in order to maintain the living conditions on earth.

  10. Forest carbon sinks in the northern hemisphere

    NARCIS (Netherlands)

    Goodale, C.L.; Apps, M.J.; Birdsey, R.A.; Field, C.B.; Heath, L.S.; Houghton, R.A.; Jenkins, J.C.; Kohlmaier, G.H.; Kurz, W.; Liu, S.R.; Nabuurs, G.J.; Nilsson, S.; Shvidenko, A.Z.

    2002-01-01

    There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measuretment-based constraints on the magnitude o

  11. Terrestrial carbon sinks and the Kyoto Protocol. The scientific issues

    Energy Technology Data Exchange (ETDEWEB)

    Dolman, H.; Nabuurs, G.J.; Kuikman, P.; Kruijt, B.; Brinkman, S. [Alterra, Wageningen (Netherlands); Vleeshouwers, L.; Verhagen, J. [Plant Research International, Wageningen (Netherlands)

    2001-07-01

    Since the publication of the IPCC special report on Land Use, Land Use Change and Forestry, considerable advances in our understanding of the global carbon cycle have occurred. This report attempts to review the terrestrial part of that cycle and assesses the implications for the implementation of then Kyoto protocol. The review assesses the impacts of the effects of continuing carbon uptake of old growth forest, interannual variability of terrestrial uptake. It is speculated that impact on N-deposition on carbon sequestration is small (of order 10%). It is unknown whether agriculture at large is a source or sink. Lack of knowledge of soil organic carbon contributes strongly to this uncertainty. The sustainability of the terrestrial sink also reviewed. It is concluded that eventually all sinks saturate, but that land use management can play a critical role in sustaining the sink strength. The role of feedback of the terrestrial carbon pools on climate change is discussed. 35 refs.

  12. A large and persistent carbon sink in the world's forests

    Science.gov (United States)

    Pan, Y.; Birdsey, R.A.; Fang, J.; Houghton, R.; Kauppi, P.E.; Kurz, W.A.; Phillips, O.L.; Shvidenko, A.; Lewis, S.L.; Canadell, J.G.; Ciais, P.; Jackson, R.B.; Pacala, S.W.; McGuire, A.D.; Piao, S.; Rautiainen, A.; Sitch, S.; Hayes, D.

    2011-01-01

    The terrestrial carbon sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem carbon studies, we estimate a total forest sink of 2.4 ?? 0.4 petagrams of carbon per year (Pg C year-1) globally for 1990 to 2007. We also estimate a source of 1.3 ?? 0.7 Pg C year-1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 ?? 0.5 Pg C year-1 partially compensated by a carbon sink in tropical forest regrowth of 1.6 ?? 0.5 Pg C year-1. Together, the fluxes comprise a net global forest sink of 1.1 ?? 0.8 Pg C year-1, with tropical estimates having the largest uncertainties. Our total forest sink estimate is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and land-use change sources minus ocean and atmospheric sinks.

  13. Aged forests could still act as carbon sinks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Old-growth forests are traditionally negligible as carbon sinks, but CAS scientists recently reported that the buildup of atmospheric carbon in the top-soils of 400-year-old forests in southern China has increased at an unexpectedly high rate up to nearly 68% from 1979 to 2003.

  14. Terrestrial vegetation carbon sinks in China, 1981―2000

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using China's ground observations, e.g., forest inventory, grassland resource, agricultural statistics, climate, and satellite data, we estimate terrestrial vegetation carbon sinks for China's major biomes between 1981 and 2000. The main results are in the following: (1) Forest area and forest biomass carbon (C) stock increased from 116.5×106 ha and 4.3 Pg C (1 Pg C = 1015 g C) in the early 1980s to 142.8×106 ha and 5.9 Pg C in the early 2000s, respectively. Forest biomass carbon density increased form 36.9 Mg C/ha (1 Mg C = 106 g C) to 41.0 Mg C/ha, with an annual carbon sequestration rate of 0.075 Pg C/a. Grassland, shrub, and crop biomass sequestrate carbon at annual rates of 0.007 Pg C/a, 0.014―0.024 Pg C/a, and 0.0125―0.0143 Pg C/a, respectively. (2) The total terrestrial vegetation C sink in China is in a range of 0.096―0.106 Pg C/a between 1981 and 2000, accounting for 14.6%―16.1% of carbon dioxide (CO2) emitted by China's industry in the same period. In addition, soil carbon sink is estimated at 0.04―0.07 Pg C/a. Accordingly, carbon sequestration by China's terrestrial ecosystems (vegetation and soil) offsets 20.8%―26.8% of its industrial CO2 emission for the study period. (3) Considerable uncertainties exist in the present study, especially in the estimation of soil carbon sinks, and need further intensive investigation in the future.

  15. Feasibility of Haze Governance Based on Carbon Sink Mode

    Institute of Scientific and Technical Information of China (English)

    Jie; HE; Quanquan; WANG

    2015-01-01

    In recent years,there are research findings of haze formation in various fields of academic circle. It has proved that causes of haze take on diverse characteristics. Thus,from both the natural and human perspective,haze governance should be diverse. Research conclusions on causes of haze formation mainly focus on special geographical structure,and meteorological factors such as relatively stable atmosphere,high rate of calm wind,high relative humidity and temperature of air,and human factors such as industrial pollution,automotive exhaust emissions,aerosol pollution,eutrophication of soil water,and change of city underlying surface. Carbon sink mode is a new channel for haze governance.In carbon sink mode,it is feasible to regulate relative humidity and temperature in air,enhance global wind,and reduce fine particles and microorganisms of air pollution,so as to reduce haze pollution. Besides,China’s special potential of carbon sink market makes it possible to govern haze on the base of carbon sink.

  16. Nanoporous clay with carbon sink and pesticide trapping properties

    OpenAIRE

    Woignier, Thierry; Duffours, L.; Colombel, P.; Dieudonné, P.

    2015-01-01

    A thorough understanding of the mechanisms and factors involved in the dynamics of organic carbon in soils is required to identify and enhance natural sinks for greenhouse gases. Some tropical soils, such as Andosols, have 3-6 fold higher concentrations of organic carbon than other kinds of soils containing classical clays. In the tropics, toxic pesticides permanently pollute soils and contaminate crops, water resources, and ecosystems. However, not all soils are equal in terms of pesticide c...

  17. Carbon sink activity and GHG budget of managed European grasslands

    Science.gov (United States)

    Klumpp, Katja; Herfurth, Damien; Soussana, Jean-Francois; Fluxnet Grassland Pi's, European

    2013-04-01

    In agriculture, a large proportion (89%) of greenhouse gas (GHG) emission saving potential may be achieved by means of soil C sequestration. Recent demonstrations of carbon sink activities of European ecosystemes, however, often questioned the existence of C storing grasslands, as though a net sink of C was observed, uncertainty surrounding this estimate was larger than the sink itself (Janssens et al., 2003, Schulze et al., 2009. Then again, some of these estimates were based on a small number of measurements, and on models. Not surprising, there is still, a paucity of studies demonstrating the existence of grassland systems, where C sequestration would exceed (in CO2 equivalents) methane emissions from the enteric fermentation of ruminants and nitrous oxide emissions from managed soils. Grasslands are heavily relied upon for food and forage production. A key component of the carbon sink activity in grasslands is thus the impact of changes in management practices or effects of past and recent management, such as intensification as well as climate (and -variation). We analysed data (i.e. flux, ecological, management and soil organic carbon) from a network of European grassland flux observation sites (36). These sites covered different types and intensities of management, and offered the opportunity to understand grassland carbon cycling and trade-offs between C sinks and CH4 and N2O emissions. For some sites, the assessment of carbon sink activities were compared using two methods; repeated soil inventory and determination of the ecosystem C budget by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports (net C storage, NCS). In general grassland, were a potential sink of C with 60±12 g C /m2.yr (median; min -456; max 645). Grazed sites had a higher NCS compared to cut sites (median 99 vs 67 g C /m2.yr), while permanent grassland sites tended to have a lower NCS compared to temporary sown grasslands (median 64 vs

  18. Land use effects on terrestrial carbon sources and sinks

    Institute of Scientific and Technical Information of China (English)

    Josep; G.; Canadell

    2002-01-01

    Current and past land use practices are critical in determining the distribution and size of global terrestrial carbon (C) sources and sinks. Althoughfossil fuel emissions dominate the anthropogenic perturbation of the global C cycle, land use still drives the largest portion of anthropogenic emissions in a number of tropical regions of Asia. The size of the emission flux owing to land use change is still the biggest uncertainty in the global C budget. The Intergovernmental Panel on Climate Change (IPCC) reported a flux term of 1.7 PgC@a-1 for 1990-1995 but more recent estimates suggest the magnitude of this source may be only of 0.96 PgC@a-1 for the 1990s. In addition, current and past land use practices are now thought to contribute to a large degree to the northern hemisphere terrestrial sink, and are the dominant driver for some regional sinks. However, mechanisms other than land use change need to be invoked in order to explain the inferred C sink in the tropics. Potential candidates are the carbon dioxide (CO2) fertilization and climate change; fertilization due to nitrogen (N) deposition is believed to be small or nil. Although the potential for managing C sinks is limited, improved land use management and new land uses such as reforestation and biomass fuel cropping, can further enhance current terrestrial C sinks. Best management practices in agriculture alone could sequester 0.4-0.8 PgC per year in soils if implemented globally. New methodologies to ensure verification and permanency of C sequestration need to be developed.

  19. Trends in the sources and sinks of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Le Quere, Corrine [University of East Anglia, Norwich, United Kingdom; Raupach, Mike [GCP, Canberra, Australia; Canadell, J.G. [CSIRO Marine and Atmospheric Research; Marland, Gregg [ORNL; Bopp, Laurent [National Center for Scientific Research, Gif-sur-Yvette, France; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environement, France; Friedlingstein, Pierre [National Center for Scientific Research, Gif-sur-Yvette, France; Viovy, Nicolas [National Center for Scientific Research, Gif-sur-Yvette, France; Conway, T.J. [NOAA, Boulder, CO; Doney, Scott C. [Woods Hole Oceanographic Institution; Feely, R. A. [NOAA Pacific Marine Environmental Laboratory; Foster, Pru [University of Bristol, UK; House, Joanna I [University of Bristol, UK; Prentice, Colin I. [University of Bristol, UK; Gurney, Kevin [Purdue University; Houghton, R.A. [Woods Hole Research Center, Woods Hole, MA; Huntingford, Chris [Center for Ecology and Hydrology, Oxon, England; Levy, Peter E. [Center for Ecology and Hydrology, Midlothian, Scotland; Lomas, M. R. [University of Sheffield; Woodward, F. I. [University of Sheffield; Majkut, Joseph [Princeton University; Sarmiento, Jorge L. [Princeton University; Metzl, Nicolas [University of Paris; Ometto, Jean P [ORNL; Randerson, James T. [University of California, Irvine; Peters, Glen P [Center for International Climate and Energy Research (CICERO), Oslo, Norway; Running, Steven [University of Montana, Missoula; Sitch, Stephen [University of Leeds, UK; Takahashi, Taro [Columbia University; Van der Werf, Guido [Universitate Amsterdam

    2009-12-01

    Efforts to control climate change require the stabilization of atmospheric CO2 concentrations. This can only be achieved through a drastic reduction of global CO2 emissions. Yet fossil fuel emissions increased by 29% between 2000 and 2008, in conjunction with increased contributions from emerging economies, from the production and international trade of goods and services, and from the use of coal as a fuel source. In contrast, emissions from land-use changes were nearly constant. Between 1959 and 2008, 43% of each year's CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties.

  20. A carbon sink pathway increases carbon productivity in cyanobacteria.

    Science.gov (United States)

    Oliver, John W K; Atsumi, Shota

    2015-05-01

    The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity.

  1. The ocean carbon sink – impacts, vulnerabilities, and challenges

    Directory of Open Access Journals (Sweden)

    C. Heinze

    2014-12-01

    Full Text Available Carbon dioxide (CO2 is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil-fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth's climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon load will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated data bases, the application of state-of-the-art Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical, and biological processes that yield both positive and negative air–sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling, and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed.

  2. The ocean carbon sink - impacts, vulnerabilities and challenges

    Science.gov (United States)

    Heinze, C.; Meyer, S.; Goris, N.; Anderson, L.; Steinfeldt, R.; Chang, N.; Le Quéré, C.; Bakker, D. C. E.

    2015-06-01

    Carbon dioxide (CO2) is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth's climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable adaptation and mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon inventory will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated databases, the application of Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical and biological processes that yield both positive and negative air-sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake) as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed.

  3. Nanoporous clay with carbon sink and pesticide trapping properties

    Science.gov (United States)

    Woignier, T.; Duffours, L.; Colombel, P.; Dieudonné, P.

    2015-07-01

    A thorough understanding of the mechanisms and factors involved in the dynamics of organic carbon in soils is required to identify and enhance natural sinks for greenhouse gases. Some tropical soils, such as Andosols, have 3-6 fold higher concentrations of organic carbon than other kinds of soils containing classical clays. In the tropics, toxic pesticides permanently pollute soils and contaminate crops, water resources, and ecosystems. However, not all soils are equal in terms of pesticide contamination or in their ability to transfer pollution to the ecosystem. Andosols are generally more polluted than the other kinds of soils but, surprisingly, they retain and trap more pesticides, thereby reducing the transfer of pesticides to ecosystems, water resources, and crops. Andosols thus have interesting environmental properties in terms of soil carbon sequestration and pesticide retention. Andosols contain a nano porous clay (allophane) with unique structures and physical properties compared to more common clays; these are large pore volume, specific surface area, and a tortuous and fractal porous arrangement. The purpose of this mini review is to discuss the importance of the allophane fractal microstructure for carbon sequestration and pesticide trapping in the soil. We suggest that the tortuous microstructure (which resembles a labyrinths) of allophane aggregates and the associated low accessibility partly explain the poor availability of soil organic matter and of any pesticides trapped in andosols.

  4. Nested atmospheric inversion for the terrestrial carbon sources and sinks in China

    Directory of Open Access Journals (Sweden)

    F. Jiang

    2013-08-01

    Full Text Available In this study, we establish a nested atmospheric inversion system with a focus on China using the Bayesian method. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and 3 additional China sites are used in this system. The core component of this system is an atmospheric transport matrix, which is created using the TM5 model with a horizontal resolution of 3° × 2°. The net carbon fluxes over the 43 global land and ocean regions are inverted for the period from 2002 to 2008. The inverted global terrestrial carbon sinks mainly occur in boreal Asia, South and Southeast Asia, eastern America and southern South America. Most China areas appear to be carbon sinks, with strongest carbon sinks located in Northeast China. From 2002 to 2008, the global terrestrial carbon sink has an increasing trend, with the lowest carbon sink in 2002. The inter-annual variation (IAV of the land sinks shows remarkable correlation with the El Niño Southern Oscillation (ENSO. The terrestrial carbon sinks in China also show an increasing trend. However, the IAV in China is not the same as that of the globe. There is relatively stronger land sink in 2002, lowest sink in 2006, and strongest sink in 2007 in China. This IAV could be reasonably explained with the IAVs of temperature and precipitation in China. The mean global and China terrestrial carbon sinks over the period 2002–2008 are −3.20 ± 0.63 and −0.28 ± 0.18 PgC yr−1, respectively. Considering the carbon emissions in the form of reactive biogenic volatile organic compounds (BVOCs and from the import of wood and food, we further estimate that China's land sink is about −0.31 PgC yr−1.

  5. Carbon sequestration in sinks. An overview of potential and costs

    Energy Technology Data Exchange (ETDEWEB)

    Kolshus, Hans H.

    2001-07-01

    Prior to the resumed climate negotiations in Bonn in July this year, it was thought that an agreement on the unresolved crunch issues of the Kyoto Protocol was unrealistic. This was primarily due to the US withdrawal from the Kyoto Protocol, and the failure of the previous climate negotiations that stranded mainly because of disagreement on the inclusion of land use, land-use change, and forestry (LULUCF) activities. The LULUCF issue is controversial in the climate negotiations, but an agreement has now been reached. This paper explores the possible contribution of LULUCF activities in promoting greenhouse gas emissions reductions. A survey on the literature of the potential and cost of LULUCF activities is therefore central. Analysis of the recent climate negotiations is also important. It is clear that the potential for carbon sequestration is large, but there are large variations in the estimates as factors such as land availability and the rate of carbon uptake complicate the calculations. There are also variations in the costs estimates, and economic analysis of LULUCF projects are not easily compared as no standard method of analysis has emerged and come into wide use. Despite the difficulties in comparing the costs of carbon sequestration, it is clear that it is a relatively inexpensive measure. Even though the potential for carbon sequestration is large, its role in reducing emissions of greenhouse gases (GHG) is limited by the Kyoto Protocol. The recent climate negotiations in Bonn and Marrakesh have specified the modalities, rules and guidelines relating to LULUCF activities. One of the main outcomes is that Japan, Canada and Russia are allowed large inclusions of sinks in their GHG emission accounts. (author)

  6. Ballast minerals and the sinking carbon flux in the ocean: carbon-specific respiration rates and sinking velocity of marine snow aggregates

    Directory of Open Access Journals (Sweden)

    M. H. Iversen

    2010-09-01

    Full Text Available Recent observations have shown that fluxes of ballast minerals (calcium carbonate, opal, and lithogenic material and organic carbon fluxes are closely correlated in the bathypelagic zones of the ocean. Hence it has been hypothesized that incorporation of biogenic minerals within marine aggregates could either protect the organic matter from decomposition and/or increase the sinking velocity via ballasting of the aggregates. Here we present the first combined data on size, sinking velocity, carbon-specific respiration rate, and composition measured directly in three aggregate types; Emiliania huxleyi aggregates (carbonate ballasted, Skeletonema costatum aggregates (opal ballasted, and aggregates made from a mix of both E. huxleyi and S. costatum (carbonate and opal ballasted. Overall average carbon-specific respiration rate was ~0.13 d−1 and did not vary with aggregate type and size. Ballasting from carbonate resulted in 2- to 2.5-fold higher sinking velocities than those of aggregates ballasted by opal. We compiled literature data on carbon-specific respiration rate and sinking velocity measured in aggregates of different composition and sources. Compiled carbon-specific respiration rates (including this study vary between 0.08 d−1 and 0.20 d−1. Sinking velocity increases with increasing aggregate size within homogeneous sources of aggregates. When compared across different particle and aggregate sources, however, sinking velocity appeared to be independent of particle or aggregate size. The carbon-specific respiration rate per meter settled varied between 0.0002 m−1 and 0.0030 m−1, and decreased with increasing aggregate size. It was lower for calcite ballasted aggregates as compared to that of similar sized opal ballasted aggregates.

  7. A large and persistent carbon sink in the World s forests

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yude [U.S. Department of Agriculture Forest Service; Birdsey, Richard A. [U.S. Department of Agriculture Forest Service; Fang, Jingyun [Peking University; Houghton, Richard [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Kauppi, Pekka [University of Helsinki; Kurz, Werner [Canadian Forest Service; Phillips, Oliver [University of Leeds, UK; Shvidenko, Anatoly [IIASA, Laxenburg, Austria; Lewis, Simon [University of Leeds, UK; Canadell, Josep [CSIRO Marine and Atmospheric Research; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environement, France; Jackson, Robert B [Duke University; Pacala, Stephen [Princeton University; Mcguire, David [University of Alaska; Piao, Shilong [Peking University; Rautiainen, Aapo [University of Helsinki; Sitch, Stephen [University of Leeds, UK; Hayes, Daniel J [ORNL

    2011-01-01

    The terrestrial carbon (C) sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem C studies, we estimated a total forest sink of 2.4 0.4 Pg C yr 1 globally for 1990-2007. We also estimated a source of 1.3 0.7 Pg C yr 1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 0.5 Pg C yr 1 partially compensated by a C sink in tropical forest regrowth of 1.6 0.5 Pg C yr 1. Together, the fluxes comprise a net global forest sink of 1.1 0.8 Pg C yr 1, with tropical estimates having the largest uncertainties. This forest sink is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and constraints of ocean and atmospheric sinks.

  8. Assessment Of Carbon Leakage In Multiple Carbon-Sink Projects: ACase Study In Jambi Province, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Rizaldi; Wasrin, Upik R.; Hendri, Perdinan; Dasanto,Bambang D.; Makundi, Willy; Hero, Julius; Ridwan, M.; Masripatin, Nur

    2007-06-01

    Rehabilitation of degraded forest land throughimplementation of carbon sink projects can increase terrestrial carbonstock. However, carbon emissions outside the project boundary, which iscommonly referred to as leakage, may reduce or negate the sequestrationbenefits. This study assessed leakage from carbon sink projects thatcould potentially be implemented in the study area comprised of elevensub-districts in the Batanghari District, Jambi Province, Sumatra,Indonesia. The study estimates the probability of a given land use/coverbeing converted into other uses/cover, by applying a logit model. Thepredictor variables were: proximity to the center of the land use area,distance to transportation channel (road or river), area of agriculturalland, unemployment (number of job seekers), job opportunities, populationdensity and income. Leakage was estimated by analyzing with and withoutcarbon sink projects scenarios. Most of the predictors were estimated asbeing significant in their contribution to land use cover change. Theresults of the analysis show that leakage in the study area can be largeenough to more than offset the project's carbon sequestration benefitsduring the period 2002-2012. However, leakage results are very sensitiveto changes of carbon density of the land uses in the study area. Byreducing C-density of lowland and hill forest by about 10 percent for thebaseline scenario, the leakage becomes positive. Further data collectionand refinement is therefore required. Nevertheless, this study hasdemonstrated that regional analysis is a useful approach to assessleakage.

  9. Ecological Meaning and Consideration of Economic Forest Carbon Sinks in China----Take Yan-Shan Chestnut for Example

    Science.gov (United States)

    Wang, Z.; Li, H.; Zhang, W. W.; Liu, S. R.

    Along with our country scientific researchers' study on native forest carbon sinks as well as the summary of the increasing amount of China's forest carbon, With the deepening of our scientists on the study of the national forest carbon sinks, forest carbon sinks has become a favorable support for climate diplomacy. Currently, a lot of work has focused on the carbon cycle, the level of carbon sinks of forest ecosystems, but the characteristics of economic forest carbon sinks are in a blank state. Beijing chestnut is one of the national food strategic security stockpiles, and estimate the potential of economic forest carbon sinks has important scientific significance to the establishment of carbon sink function area, and expansion of sustainable economic and social development of response measures.

  10. North America carbon dioxide sources and sinks: magnitude, attribution, and uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    King, Anthony W.; Hayes, Daniel J.; Huntzinger, Deborah N.; West, Tristram O.; Post, W. M.

    2012-12-01

    North America is both a source and sink of atmospheric CO2. Sources, predominately fossil-fuel combustion in the United States along with contributions from deforestation in Mexico, add CO2 to the atmosphere. Most North America ecosystems, particularly regrowing forests in the United States, are sinks for atmospheric CO2. CO2 is removed from the atmosphere in photosynthesis, converted into biomass and stored as carbon in vegetation, soil and wood products. Fossil-fuel emissions dominate the North American source-sink balance. North America is a net source of atmospheric CO2 with ecosystem sinks balancing approximately 35% of fossil-fuel CO2 emissions from North America.

  11. Mangrove production and carbon sinks: A revision of global budget estimates

    Science.gov (United States)

    Bouillon, S.; Borges, A.V.; Castaneda-Moya, E.; Diele, K.; Dittmar, T.; Duke, N.C.; Kristensen, E.; Lee, S.-Y.; Marchand, C.; Middelburg, J.J.; Rivera-Monroy, V. H.; Smith, T. J.; Twilley, R.R.

    2008-01-01

    Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove primary production from the literature results in a conservative estimate of ???-218 ?? 72 Tg C a-1. When using the best available estimates of various carbon sinks (organic carbon export, sediment burial, and mineralization), it appears that >50% of the carbon fixed by mangrove vegetation is unaccounted for. This unaccounted carbon sink is conservatively estimated at ??? 112 ?? 85 Tg C a-1, equivalent in magnitude to ??? 30-40% of the global riverine organic carbon input to the coastal zone. Our analysis suggests that mineralization is severely underestimated, and that the majority of carbon export from mangroves to adjacent waters occurs as dissolved inorganic carbon (DIC). CO2 efflux from sediments and creek waters and tidal export of DIC appear to be the major sinks. These processes are quantitatively comparable in magnitude to the unaccounted carbon sink in current budgets, but are not yet adequately constrained with the limited published data available so far. Copyright 2008 by the American Geophysical Union.

  12. Mangrove carbon sink. Do burrowing crabs contribute to sediment carbon storage? Evidence from a Kenyan mangrove system

    OpenAIRE

    2014-01-01

    Mangrove ecosystems are acknowledged as a significant carbon reservoir, with a potential key role as carbon sinks. Little however is known on sediment/soil capacity to store organic carbon and the impact of benthic fauna on soil organic carbon (SOC) stock in mangrove C-poor soils. This study aimed to investigate the effects of macrobenthos on SOC storage and dynamic in mangrove forest at Gazi Bay (Kenya). Although the relatively low amount of organic carbon (OC%) in these soils, they resulted...

  13. Combustion of biomass as a global carbon sink

    OpenAIRE

    2008-01-01

    This note is intended to highlight the important role of black carbon produced from biomass burning in the global carbon cycle, and encourage further research in this area. Consideration of the fundamental physical chemistry of cellulose thermal decomposition suggests that suppression of biomass burning or biasing burning practices to produce soot-free flames must inevitably transfer more carbon to the atmosphere. A simple order-of-magnitude quantitative analysis indicates that black carbon m...

  14. Combustion of biomass as a global carbon sink

    CERN Document Server

    Ball, Rowena

    2008-01-01

    This note is intended to highlight the important role of black carbon produced from biomass burning in the global carbon cycle, and encourage further research in this area. Consideration of the fundamental physical chemistry of cellulose thermal decomposition suggests that suppression of biomass burning or biasing burning practices to produce soot-free flames must inevitably transfer more carbon to the atmosphere. A simple order-of-magnitude quantitative analysis indicates that black carbon may be a significant carbon reservoir that persists over geological time scales.

  15. Seagrass sediments as a global carbon sink: Isotopic constraints

    Science.gov (United States)

    Kennedy, Hilary; Beggins, Jeff; Duarte, Carlos M.; Fourqurean, James W.; Holmer, Marianne; Marbã, Núria; Middelburg, Jack J.

    2010-12-01

    Seagrass meadows are highly productive habitats found along many of the world's coastline, providing important services that support the overall functioning of the coastal zone. The organic carbon that accumulates in seagrass meadows is derived not only from seagrass production but from the trapping of other particles, as the seagrass canopies facilitate sedimentation and reduce resuspension. Here we provide a comprehensive synthesis of the available data to obtain a better understanding of the relative contribution of seagrass and other possible sources of organic matter that accumulate in the sediments of seagrass meadows. The data set includes 219 paired analyses of the carbon isotopic composition of seagrass leaves and sediments from 207 seagrass sites at 88 locations worldwide. Using a three source mixing model and literature values for putative sources, we calculate that the average proportional contribution of seagrass to the surface sediment organic carbon pool is ˜50%. When using the best available estimates of carbon burial rates in seagrass meadows, our data indicate that between 41 and 66 gC m-2 yr-1 originates from seagrass production. Using our global average for allochthonous carbon trapped in seagrass sediments together with a recent estimate of global average net community production, we estimate that carbon burial in seagrass meadows is between 48 and 112 Tg yr-1, showing that seagrass meadows are natural hot spots for carbon sequestration.

  16. Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

    Directory of Open Access Journals (Sweden)

    Thomas A. Douglas

    2014-12-01

    Full Text Available Abstract Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in soil and vegetation. The roles of fire, forest succession, and the presence (or absence of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in boreal ecosystems for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle we developed this review paper by incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We surveyed estimates of aboveground and belowground carbon stocks for interior Alaska boreal ecosystems and summarized methane and carbon dioxide fluxes. These data have been converted into similar units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance. A novel research question is how compounding disturbances affect carbon sources and sinks associated with boreal ecosystem processes. Finally, we provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution

  17. A new direction in search of "missing" carbon sinks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ A CAS scientist succeeds in developing a new direction for exploring the inorganic carbon cycle of the earth. His creative work was recently reported by the 20th issue of Chinese Science Bulletin in 2007.

  18. Southern Ocean Carbon Sink Constraints from Radiocarbon in Drake Passage Air

    Science.gov (United States)

    Lindsay, C. M.; Lehman, S.; Miller, J. B.

    2014-12-01

    The Southern Ocean is one of the earth's largest regional net carbon sinks due to strong westerly winds, which drive surface gas exchange, deep mixing and upwelling. The strength of the sink is set by complex interactions between the physical circulation, gas exchange and biological activity in surface waters. Recent work by others has predicted that global warming may weaken the sink by strengthening the regional winds, increasing upwelling and the flux of deep, naturally carbon-rich and radiocarbon-depleted water into the surface mixed layer. The resulting decrease in the air-sea pCO2 gradient is thought to overwhelm other compensating changes, causing a weakened net sink. Here we demonstrate the use of precise measurements of radiocarbon in Drake Passage air (14CO2) to detect short-term fluctuations in the Southern Ocean gross sea-to-air C flux, and by extension, possible changes in the net carbon sink and their underlying causes. Drake Passage boundary layer air has been sampled since 2006 at roughly fortnightly intervals as part of NOAA's Cooperative Air Sampling Network, resulting in a 5-year high-resolution 14CO2 time-series with accompanying same-flask CO2 concentration measurements. Atmospheric measurements at Drake Passage are representative of zonal average exchange fluxes due to strong mixing by the westerly winds. In preliminary results, anomalously low ∆14C values are correlated with positive states of the Southern Annular Mode, a hemispheric-scale indicator of stronger westerly winds in the high latitude Southern Ocean. Simulations from the TM5 atmospheric transport model with a detailed global radiocarbon budget are used to interpret the results. These results appear to support the hypothesized link between stronger westerly winds and a weaker Southern Ocean carbon sink.

  19. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

    Science.gov (United States)

    Woody encroachment is a globally occurring phenomenon that is thought to contribute significantly to the global carbon (C) sink. The C contribution needs to be estimated at regional and local scales to address large uncertainties present in the global- and continental-scale estimates and guide regio...

  20. Carbon sink in Phoebe bournei artificial forest ecosystem

    Institute of Scientific and Technical Information of China (English)

    Mingdong MA; Chengde LUO; Hong JIANG; Yuejian LIU; Xi LI

    2009-01-01

    Biomass, carbon content, carbon storage and spatial distribution in the 32-year-old Phoebe bournei artificial forest were measured. The mean biomass of the forest stand was 174.33 t/hm2, among which the arbor layer was 166.73 t/hm2, which accounted for 95.6%. Carbon contents of stems, barks, branches, leaves, root, shrub layer, herb layer, lichen layer and litter layer were 0.5769 g C/g, 0.4654 g C/g, 0.5232 g C/g, 0.4958 g C/g, 0.4931 g C/g, 0.4989 g C/g, 0.4733 g C/g, 0.4143 g C/g, 0.3882 g C/g, respectively. The mean carbon content of soil was 0.0139 g C/g, which reduced gradually along with soil depth. Total carbon storage of the P. bournei stand ecosystem was 227.59 t/hm2, among which the arbor layer accounted for 40.13% (91.33 t/hm2), the shrub layer accounted for 0.17% (0.38 t/hm2), the herb layer accounted for 0.76% (1.71 t/hm2), the lichen layer accounted for 0.28% (0.63 t/hm2), and the litter layer accounted for 0.29% (0.66 t/hm2). Carbon content (0-80 cm) of the forest soil was 58.40% (132.88 t/hm2). Spatial distribution ranking of carbon storage was: soil layer (0-80 cm) > arbor layer > herb layer > litter layer > lichen layer > shrub layer. Net production of the forest stand was 8.5706 t/(hm2-a), in which the arbor layer was 6.6691 t/(hm2-a), and it accounted for 77.82%. Net annual carbon sequestration of the P. bournei stand was 4.2536 t/(hm2 a),and the arbor layer was 3.5736 t/(hm2. a), which accountedfor 84.01%.

  1. Nitrogen Dynamics are a Key Factor in Explaining Global Land Carbon Sink

    Science.gov (United States)

    Huntzinger, D. N.; Michalak, A. M.; Schwalm, C.; Ciais, P.; Schaefer, K. M.; King, A. W.; Wei, Y.; Cook, R. B.; Fisher, J. B.; Hayes, D. J.; Huang, M.; Ito, A.; Jain, A. K.; Lei, H.; Lu, C.; Maignan, F.; Mao, J.; Parazoo, N.; Peng, S.; Poulter, B.; Ricciuto, D. M.; Shi, X.; Tian, H.; Wang, W.; Zeng, N.; Zhao, F.

    2015-12-01

    The terrestrial carbon cycle plays a critical role in regulating the amount of anthropogenic emissions that remain in the atmosphere. Yet, land-atmosphere carbon dynamics are one of the largest sources of uncertainty in projections of future climate. Reducing this uncertainty requires understanding the relative role of various drivers to land carbon uptake. We use an ensemble of land surface models to quantify the influence of climate, land use history, atmospheric CO2, and nitrogen deposition on the strength of the net land sink over the past 110 years. Each model can be thought of as one realization of terrestrial carbon cycling and the factors most important in controlling land sink strength. Using a series of sensitivity simulations, we identify the dominant drivers to the net land sink that emerge consistently across models, both globally and regionally. We find that the relative importance of external forcing factors on the strength of net land carbon uptake varies considerably across models and depends strongly on whether nitrogen cycling is explicitly simulated. Models without a nitrogen cycle estimate cumulative land carbon uptake (since 1959) that is 3 times greater (93.3 ± 84.1 PgC) than global mass balance constraints (34.6 ± 41.6 PgC). Surprisingly, the greatest impacts are seen in the tropics, where coupled carbon-nitrogen cycle models estimate CO2 fertilization and climate affects that are ~60% weaker than models without a nitrogen cycle. The results highlight the importance of model structure on the inferred sensitivity of land carbon uptake to external forcing factors. The range in sensitivity across models is important for future climate projections since the differences in the processes that explain trends in net land sink strength between models with and without nitrogen dynamics can lead to very different future trajectories of atmospheric CO2 and thus climate.

  2. Climate change and sustainability of the carbon sink in Maritime salt marshes

    Energy Technology Data Exchange (ETDEWEB)

    Chmura, G.L. [McGill Univ., Montreal, PQ (Canada). Dept. of Geography, Global Environmental and Climate Change Centre

    2008-07-01

    Ideal carbon sinks do not emit greenhouse gases (GHGs) and are sustainable with future trends in global warming. This presentation discussed the potential for using Maritime salt marshes as carbon sinks. The marshes are covered with grasses adapted to saline soils. Photosynthesis by the marsh plants and algae fix the carbon dioxide (CO{sub 2}) directly from the atmosphere. The carbon is then buried by mineral sediment. Wetlands without saline water are known to produce methane. The carbon in salt marsh soils does not significantly decline with depth or time. Salt marshes and mangroves store an average of 210 g of CO{sub 2} per m{sup 2} per year. The tidal floodwaters keep the soils wet, which allows for slow decomposition. Canadian salt marsh soils have increased in thickness at a rate of between 2 to 4 mm per year. Measurement programs have demonstrated the sustainability of inner Bay of Fundy marshes in relation to rising sea levels. Opportunities for carbon sinks also exist in dyked marshes in the region. It was concluded that the salt marshes can account for between 4 to 6 per cent of Canada's targeted reductions under the Kyoto Protocol. tabs., figs.

  3. Carbon emissions and sinks in agro-ecosystems of China

    Institute of Scientific and Technical Information of China (English)

    林而达; 李月娥; 郭李萍

    2002-01-01

    Besides ruminant animals and their wastes, soil is an important regula ting medium in carbon cycling. The soil can be both a contributor to climate cha nge and a recipient of impacts. In the past, land cultivation has generally resu lted in considerable depletion of soil organic matter and the release of greenho use gases (GHGs) into the atmosphere. The observation in the North-South Transec t of Eastern China showed that climate change and land use strongly impact all s oil processes and GHG exchanges between the soil and the atmosphere. Soil manage ment can restore organic carbon by enhancing soil structure and fertility and by doing so mitigating the negative impacts of atmospheric greenhouses on climate. A wide estimation carried out in China shows that carbon sequestration potentia l is about 77.2 MMt C/a (ranging from 26.1—128.3 MMt C/a) using proposed IPCC a ctivities during the next fifty years.

  4. From carbon sink to carbon source: extensive peat oxidation in insular Southeast Asia since 1990

    Science.gov (United States)

    Miettinen, Jukka; Hooijer, Aljosja; Vernimmen, Ronald; Liew, Soo Chin; Page, Susan E.

    2017-02-01

    Tropical peatlands of the western part of insular Southeast Asia have experienced extensive land cover changes since 1990. Typically involving drainage, these land cover changes have resulted in increased peat oxidation in the upper peat profile. In this paper we provide current (2015) and cumulative carbon emissions estimates since 1990 from peat oxidation in Peninsular Malaysia, Sumatra and Borneo, utilizing newly published peatland land cover information and the recently agreed Intergovernmental Panel on Climate Change (IPCC) peat oxidation emission values for tropical peatland areas. Our results highlight the change of one of the Earth’s most efficient long-term carbon sinks to a short-term emission source, with cumulative carbon emissions since 1990 estimated to have been in the order of 2.5 Gt C. Current (2015) levels of emissions are estimated at around 146 Mt C yr‑1, with a range of 132–159 Mt C yr‑1 depending on the selection of emissions factors for different land cover types. 44% (or 64 Mt C yr‑1) of the emissions come from industrial plantations (mainly oil palm and Acacia pulpwood), followed by 34% (49 Mt C yr‑1) of emissions from small-holder areas. Thus, altogether 78% of current peat oxidation emissions come from managed land cover types. Although based on the latest information, these estimates may still include considerable, yet currently unquantifiable, uncertainties (e.g. due to uncertainties in the extent of peatlands and drainage networks) which need to be focused on in future research. In comparison, fire induced carbon dioxide emissions over the past ten years for the entire equatorial Southeast Asia region have been estimated to average 122 Mt C yr‑1 (www.globalfiredata.org/_index.html). The results emphasise that whilst reducing emissions from peat fires is important, urgent efforts are also needed to mitigate the constantly high level of emissions arising from peat drainage, regardless of fire occurrence.

  5. Physical and Economic Integration of Carbon Capture Methods with Sequestration Sinks

    Science.gov (United States)

    Murrell, G. R.; Thyne, G. D.

    2007-12-01

    Currently there are several different carbon capture technologies either available or in active development for coal- fired power plants. Each approach has different advantages, limitations and costs that must be integrated with the method of sequestration and the physiochemical properties of carbon dioxide to evaluate which approach is most cost effective. For large volume point sources such as coal-fired power stations, the only viable sequestration sinks are either oceanic or geological in nature. However, the carbon processes and systems under consideration produce carbon dioxide at a variety of pressure and temperature conditions that must be made compatible with the sinks. Integration of all these factors provides a basis for meaningful economic comparisons between the alternatives. The high degree of compatibility between carbon dioxide produced by integrated gasification combined cycle technology and geological sequestration conditions makes it apparent that this coupling currently holds the advantage. Using a basis that includes complete source-to-sink sequestration costs, the relative cost benefit of pre-combustion IGCC compared to other post-combustion methods is on the order of 30%. Additional economic benefits arising from enhanced oil recovery revenues and potential sequestration credits further improve this coupling.

  6. Abundance and sinking of particulate black carbon in the western Arctic and Subarctic Oceans

    Science.gov (United States)

    Fang, Ziming; Yang, Weifeng; Chen, Min; Zheng, Minfang; Hu, Wangjiang

    2016-07-01

    The abundance and sinking of particulate black carbon (PBC) were examined for the first time in the western Arctic and Subarctic Oceans. In the central Arctic Ocean, high PBC concentrations with a mean of 0.021 ± 0.016 μmol L‑1 were observed in the marginal ice zone (MIZ). A number of parameters, including temperature, salinity and 234Th/238U ratios, indicated that both the rapid release of atmospherically deposited PBC on sea ice and a slow sinking rate were responsible for the comparable PBC concentrations between the MIZ and mid-latitudinal Pacific Ocean (ML). On the Chukchi and Bering Shelves (CBS), PBC concentrations were also comparable to those obtained in the ML. Further, significant deficits of 234Th revealed the rapid sinking of PBC on the CBS. These results implied additional source terms for PBC in addition to atmospheric deposition and fluvial discharge on the western Arctic shelves. Based on 234Th/238U disequilibria, the net sinking rate of PBC out of the surface water was ‑0.8 ± 2.5 μmol m‑3 d‑1 (mean ± s.d.) in the MIZ. In contrast, on the shelves, the average sinking rate of PBC was 6.1 ± 4.6 μmol m‑3 d‑1. Thus, the western Arctic Shelf was probably an effective location for burying PBC.

  7. The influence of Southern Ocean winds on the North Atlantic carbon sink

    Science.gov (United States)

    Bronselaer, Ben; Zanna, Laure; Munday, David R.; Lowe, Jason

    2016-06-01

    Observed and predicted increases in Southern Ocean winds are thought to upwell deep ocean carbon and increase atmospheric CO2. However, Southern Ocean dynamics affect biogeochemistry and circulation pathways on a global scale. Using idealized Massachusetts Institute of Technology General Circulation Model (MITgcm) simulations, we demonstrate that an increase in Southern Ocean winds reduces the carbon sink in the North Atlantic subpolar gyre. The increase in atmospheric CO2 due to the reduction of the North Atlantic carbon sink is shown to be of the same magnitude as the increase in atmospheric CO2 due to Southern Ocean outgassing. The mechanism can be described as follows: The increase in Southern Ocean winds leads to an increase in upper ocean northward nutrient transport. Biological productivity is therefore enhanced in the tropics, which alters the chemistry of the subthermocline waters that are ultimately upwelled in the subpolar gyre. The results demonstrate the influence of Southern Ocean winds on the North Atlantic carbon sink and show that the effect of Southern Ocean winds on atmospheric CO2 is likely twice as large as previously thought in past, present, and future climates.

  8. Strong carbon sink of monsoon tropical seasonal forest in Southern Vietnam

    Science.gov (United States)

    Deshcherevskaya, Olga; Anichkin, Alexandr; Avilov, Vitaly; Duy Dinh, Ba; Luu Do, Phong; Huan Tran, Cong; Kurbatova, Julia

    2014-05-01

    Comparison between anthropogenic emission of carbon dioxide and atmospheric carbon pool change displays that only half of emitted CO2 remains in air, leaving so-called 'missing sink' of carbon. Terrestrial biosphere and ocean accumulate each about a half of this value (Gifford, 1994). Forest biomes play the decisive role in 'missing sink' because of high primary production flux and large carbon pool. Almost all the sink belongs to boreal forests, because warming and wetting coupled with increasing CO2 concentration and N deposition gives more favorable conditions for boreal ecosystems. On the contrary, tropical climate changes effect on forests is not obvious, probably cause more drought conditions; tropical forests suffer from 1.2 % per year area reduction and disturbance. Whether primary tropical forests act as carbon sink is still unclear. Biomass inventories at 146 forest plots across all the tropics in 1987-1997 revealed low carbon sink in humid forests biomass of 49 (29-66; 95% C.I.) g C m-2 year-1 on average (Malhi, 2010). Estimates for undisturbed African forests are close to global (Ciais et al., 2008). Eddy covariance (EC) observations with weak-turbulence correction in Amazonia reveal near-zero or small negative (i.e. sink) balance (Clark, 2004). Three EC sites in SE Asia primary forests give near-zero balance again (Saigusa et al., 2008; Kosugi et al., 2012). There are two main groups of explanations of moderate tropical carbon sink: (a) recovering of large-disturbance in the past or (b) response to current atmospheric changes: increase of CO2 concentration and/or climate change. So, strong carbon accumulation is not common for primary tropical forests. In this context sink of 402 g C m-2 in 2012 at EC station of Nam Cat Tien (NCT), Southern Vietnam (N 11°27', E 107°24', 134 m a.s.l.) in primary monsoon tropical forest looks questionably. EC instrument set at NCT consists of CSAT3 sonic anemometer and LI-7500A open-path gas analyzer. All the standard

  9. Vulnerability of the peatland carbon sink to sea-level rise

    Science.gov (United States)

    Whittle, Alex; Gallego-Sala, Angela V.

    2016-06-01

    Freshwater peatlands are carbon accumulating ecosystems where primary production exceeds organic matter decomposition rates in the soil, and therefore perform an important sink function in global carbon cycling. Typical peatland plant and microbial communities are adapted to the waterlogged, often acidic and low nutrient conditions that characterise them. Peatlands in coastal locations receive inputs of oceanic base cations that shift conditions from the environmental optimum of these communities altering the carbon balance. Blanket bogs are one such type of peatlands occurring in hyperoceanic regions. Using a blanket bog to coastal marsh transect in Northwest Scotland we assess the impacts of salt intrusion on carbon accumulation rates. A threshold concentration of salt input, caused by inundation, exists corresponding to rapid acidophilic to halophilic plant community change and a carbon accumulation decline. For the first time, we map areas of blanket bog vulnerable to sea-level rise, estimating that this equates to ~7.4% of the total extent and a 0.22 Tg yr‑1 carbon sink. Globally, tropical peatlands face the proportionally greatest risk with ~61,000 km2 (~16.6% of total) lying ≤5 m elevation. In total an estimated 20.2 ± 2.5 GtC is stored in peatlands ≤5 m above sea level, which are potentially vulnerable to inundation.

  10. Harvested wood products and carbon sink in a young beech high forest

    Directory of Open Access Journals (Sweden)

    Pilli R

    2008-03-01

    Full Text Available According to art. 3.4 of the Kyoto Protocol (KP, Italy has elected forest management as additional human-induced activity to attain the goal of reduction in greenhouse gas emissions. The whole forest area not subjected to afforestation, reforestation or deforestation processes since 1990 will be considered as managed forest. In order to analyse different management strategies, the Carbon-Pro Project, involving 9 partners of the European CADSES area, considered a young beech high forest (ex-coppice, defined as "transitory silvicultural system" as a common case study for the Pre-alps region. Using data collected with forest plans during the period 1983 - 2005, aboveground and belowground forest carbon stock and sink of a specific forest compartment were estimated by the Carbon Stock Method proposed by the IPCC Guidelines. In order to apply this approach 41 trees were cut and a species-specific allometric equation was developed. Considering the aboveground tree biomass, the carbon sink amounts to 1.99 and 1.84 Mg C ha-1 y-1 for the period 1983 - 1994 and 1994 - 2005 respectively. Adding the belowground tree biomass, the estimated sink amounts to 2.59 and 2.39 Mg C ha-1 y-1 for each period. Taking the harvested wood products (firewood, the total carbon sequestration during the second period is 0.16 Mg C ha-1 y-1. The case study highlights the possible rules for the different management strategies. In effect, the utilisation of the entire increase in aboveground biomass as firewood gives an energy substitution effect but, according to the Marrakesh Accords, it cannot be accounted for the KP. On the other hand, an accumulation strategy gives the maximum possible carbon absorption and retention.

  11. Tropical nighttime warming as a dominant driver of variability in the terrestrial carbon sink.

    Science.gov (United States)

    Anderegg, William R L; Ballantyne, Ashley P; Smith, W Kolby; Majkut, Joseph; Rabin, Sam; Beaulieu, Claudie; Birdsey, Richard; Dunne, John P; Houghton, Richard A; Myneni, Ranga B; Pan, Yude; Sarmiento, Jorge L; Serota, Nathan; Shevliakova, Elena; Tans, Pieter; Pacala, Stephen W

    2015-12-22

    The terrestrial biosphere is currently a strong carbon (C) sink but may switch to a source in the 21st century as climate-driven losses exceed CO2-driven C gains, thereby accelerating global warming. Although it has long been recognized that tropical climate plays a critical role in regulating interannual climate variability, the causal link between changes in temperature and precipitation and terrestrial processes remains uncertain. Here, we combine atmospheric mass balance, remote sensing-modeled datasets of vegetation C uptake, and climate datasets to characterize the temporal variability of the terrestrial C sink and determine the dominant climate drivers of this variability. We show that the interannual variability of global land C sink has grown by 50-100% over the past 50 y. We further find that interannual land C sink variability is most strongly linked to tropical nighttime warming, likely through respiration. This apparent sensitivity of respiration to nighttime temperatures, which are projected to increase faster than global average temperatures, suggests that C stored in tropical forests may be vulnerable to future warming.

  12. [Research progress on carbon sink function of agroforestry system under climate change].

    Science.gov (United States)

    Xie, Ting-Ting; Su, Pei-Xi; Zhou, Zi-Juan; Shan, Li-Shan

    2014-10-01

    As a land comprehensive utilization system, agroforestry system can absorb and fix CO2 effectively to increase carbon storage, and also reduces greenhouse effect convincingly while reaching the aim of harvest. The regulatory role in CO2 makes humans realize that agroforestry systems have significant superiority compared with single cropping systems, therefore, understanding the carbon sinks of different components in an agroforestry system and its influencing factors play an important role in studying global carbon cycle and accurate evaluation of carbon budget. This paper reviewed the concept and classification of agroforestry system, and then the carbon sequestration potentials of different components in agroforestry systems and influencing factors. It was concluded that the carbon sequestration rate of plants from different agroforestry systems in different regions are highly variable, ranging from 0.59 to 11.08 t C · hm(-2) · a(-1), and it is mainly influenced by climatic factors and the characteristics of agroforestry systems (species composition, tree density and stand age). The soil C sequestration of any agroforestry system is influenced by the amount and quality of biomass input provided by tree and nontree components of the system and the soil properties such as soil texture and soil structure. Overall the amount of carbon storage in any agroforestry system depends on the structure and function of its each component. The future studies should focus on the carbon sink functions of structurally optimized agroforestry systems, the temporal variation and spatial distribution pattern of carbon storage in agroforestry system and its carbon sequestration mechanism in a long time.

  13. Role of Carbonic Anhydrase as an Activator in Carbonate Rock Dissolution and Its Implication for Atmospheric CO2 Sink

    Institute of Scientific and Technical Information of China (English)

    刘再华

    2001-01-01

    The conversion of CO2 into H+ and is a relatively slow reaction. Hence, its kinetics may be rate determining in carbonate rock dissolution. Carbonic anhydrase (CA), which is widespread in nature, was used to catalyze the CO2 conversion process in dissolution experiments of limestone and dolomite. It was found that the rate of dissolution increases by a factor of about 10 after the addition of CA at a high CO2 partial pressure (Pco2) for limestone and about 3 at low Pco2 for dolomite. This shows that reappraisal is necessary for the importance of chemical weathering (including carbonate rock dissolution and silicate weathering) in the atmospheric CO2 sink and the mysterious missing sink in carbon cycling. It is doubtless that previous studies of weathering underestimated weathering rates due to the ignorance of CA as an activator in weathering, thus the contribution of weathering to the atmospheric CO2 sink is also underestimated. This finding also shows the need to examine the situ distribution and activity of CA in different waters and to investigate the role of CA in weathering.``

  14. Is marine dissolved organic matter the "missing sink" for soil-derived black carbon?

    Science.gov (United States)

    Dittmar, Thorsten; Suryaputra, I. Gusti N. A.; Niggemann, Jutta

    2010-05-01

    The thermal alteration of biomass during wildfires can be an important factor for the stabilization of organic matter in soils. Black carbon, i.e. biochars and soot, is more resistant to biodegradation than unaltered biomass, and it can therefore accumulate in soils and sediments. Our knowledge on the turnover of black carbon is still very fragmentary, and the known loss rates do not account for the estimated production rates. Major loss mechanisms remain unidentified or have been underestimated. Recently, we have identified a major thermogenic component in dissolved organic matter (DOM) of the deep ocean. We hypothesize that black carbon in soils is solubilized over time, probably via microbial interaction, and transported via rivers into the ocean. DOM, one of the largest organic carbon pools on earth, could therefore be an important transport medium of soil-derived black carbon. A case study was performed in the Suwannee River estuary and adjacent oceanic shelf (Florida, USA). The Suwannee River drains extensive wetlands and fire-impacted forests. The fate of dissolved black carbon was traced from the river through its estuary into the open Gulf of Mexico. Black carbon was molecularly quantified as benzenepolycarboxylic acids after nitric acid oxidation via a new UPLC method (ultra-performance liquid chromatography). The molecular analysis was accompanied by optical (excitation-emission matrix fluorescence and absorbance spectroscopy) and elemental characterization of DOM. A major component (approx. 10% on a carbon basis) of Suwannee River DOM could be identified as black carbon. The concentration of black carbon decreased offshore, and on the open ocean only about 1% of DOM could be identified as black carbon. In the deep ocean, the thermogenic component of DOM is higher and approx. 2.4% of DOM. The surface ocean must therefore be an efficient sink for dissolved black carbon. We hypothesize that sunlight may initiate photochemical reactions that cause a loss of

  15. The relative contributions of forest growth and areal expansion to forest biomass carbon sinks in China

    Directory of Open Access Journals (Sweden)

    P. Li

    2015-06-01

    Full Text Available Forests play a leading role in regional and global terrestrial carbon (C cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area and forest growth (increase in biomass density. Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests was a larger contributor to C sinks than forest growth for all forests and planted forests in China (74.6 vs. 25.4 % for all forests, and 62.4 vs. 37.8 % for plantations. However, for natural forests, forest growth made a larger contribution than areal expansion (60.4 vs. 39.6 %. The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 to 61.0 % in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation can continue to increase the C sink of China's forests in the future subject to persistently-increasing forest growth after establishment of plantation.

  16. Sediment carbon sink in low-density temperate eelgrass meadows (Baltic Sea)

    Science.gov (United States)

    Jankowska, Emilia; Michel, Loïc. N.; Zaborska, Agata; Włodarska-Kowalczuk, Maria

    2016-12-01

    Seagrass meadows are highly productive habitats that can act as "blue carbon sinks" in coastal ecosystems by facilitating sedimentation and trapping particles. However, the magnitude and occurrence of these effects may be species and density dependent. The present study is the first estimation of seagrass sediment carbon sink in the temperate Zostera marina beds in the Baltic Sea. Several descriptors of organic matter characteristics, along with possible organic matter sources in the sediment were compared at vegetated and unvegetated bottoms. The 210Pb dating of the sediment has been used for accumulation rate assessment. The photopigments and POC concentrations in sediments were higher in vegetated bottoms. The SIAR (Stable Isotopes in R) mixing model based on nitrogen and carbon stable isotope values, indicated that higher percentages of organic matter originated from seagrass production in vegetated sediments (40-45%) compared to unvegetated ones (5-21%). The carbon stock in the upper 10 cm of the vegetated sediments ranged from 50.2 ± 2.2 to 228.0 ± 11.6 (g m-2), whereas the annual C accumulation amount from 0.84 ± 0.2 to 3.85 ± 1.2 (g m-2 yr-1). Our study shows that even the relatively weakly developed vegetation of the small temperate seagrass species enhance organic carbon concentration in the sediments. Estimated carbon stock was much lower than those reported for most of the seagrass meadows elsewhere, and the carbon burial rate was the lowest ever reported. Evidently, the global calculations of sediment carbon stock should be reconsidered by taking into account density and species-related variability.

  17. Carbon sinks and emissions trading under the Kyoto Protocol: a legal analysis.

    Science.gov (United States)

    Bettelheim, Eric C; D'Origny, Gilonne

    2002-08-15

    The controversy over the issues of carbon sinks and emissions trading nearly aborted the Kyoto Protocol. The lengthy and intense debate over the roles that each are to play under the Protocol and the consequent political compromises has resulted in a complex set of provisions and an arcane nomenclature. The distinction drawn between the use of carbon sinks in developed countries under Joint Implementation and their use in developing countries under the Clean Development Mechanism (CDM) is a particular source of intricacy. It is at least arguable that key elements of the compromises reached at COP-6 and COP-7 in this regard are inconsistent with the terms of the Protocol and are ultra vires the Convention on Climate Change. This is a source of both uncertainty and potential legal challenge. Not only do the recent decisions create needless complexity, they also clearly discriminate against developing nations. Among the recent political compromises is the creation of a third type of non-bankable but tradeable unit with respect to forest management, which is only available to Annex I countries. The result is an anomalous one in which a variety of otherwise equivalent carbon credits can be generated under three different regimes including one, the CDM, that is subject to an elaborate regulatory overlay that discriminates against carbon sequestration by developing countries. For example, complying developed countries can essentially self-certify sequestration projects. In contrast, projects in developing countries must obtain prior approval from a subsidiary body, the CDM Executive Board, mandated to require detailed information and impose substantive and procedural hurdles not required or imposed by its companion body, the Article 6 Supervisory Committee on Joint Implementation Projects. The parallel and related debate over the third 'flexibility' mechanism, emissions trading, compounded the complexity of an already asymmetric and bifurcated system. The new requirements

  18. Biogeophysical feedbacks enhance Arctic terrestrial carbon sink in regional Earth system dynamics

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2014-05-01

    Full Text Available Continued warming of the Arctic will likely accelerate terrestrial carbon (C cycling by increasing both uptake and release of C. There are still large uncertainties in modelling Arctic terrestrial ecosystems as a source or sink of C. Most modelling studies assessing or projecting the future fate of C exchange with the atmosphere are based an either stand-alone process-based models or coupled climate–C cycle general circulation models, in either case disregarding biogeophysical feedbacks of land surface changes to the atmosphere. To understand how biogeophysical feedbacks will impact on both climate and C budget over Arctic terrestrial ecosystems, we apply the regional Earth system model RCA-GUESS over the CORDEX-Arctic domain. The model is forced with lateral boundary conditions from an GCMs CMIP5 climate projection under the RCP 8.5 scenario. We perform two simulations with or without interactive vegetation dynamics respectively to assess the impacts of biogeophysical feedbacks. Both simulations indicate that Arctic terrestrial ecosystems will continue to sequester C with an increased uptake rate until 2060s–2070s, after which the C budget will return to a weak C sink as increased soil respiration and biomass burning outpaces increased net primary productivity. The additional C sinks arising from biogeophysical feedbacks are considerable, around 8.5 Gt C, accounting for 22% of the total C sinks, of which 83.5% are located in areas of Arctic tundra. Two opposing feedback mechanisms, mediated by albedo and evapotranspiration changes respectively, contribute to this response. Albedo feedback dominates over winter and spring season, amplifying the near-surface warming by up to 1.35 K in spring, while evapotranspiration feedback dominates over summer exerting the evaporative cooling by up to 0.81 K. Such feedbacks stimulate vegetation growth with an earlier onset of growing-season, leading to compositional changes in woody plants and vegetation

  19. Ozone pollution effects on the land carbon sink in the future greenhouse world

    Science.gov (United States)

    Unger, N.; Yue, X.

    2015-12-01

    Ozone pollution has huge impacts on the carbon balance in the United States, Europe and China. While terrestrial ecosystems provide an important sink for surface ozone through stomatal uptake, this process damages photosynthesis, reduces plant growth and biomass accumulation, and affects stomatal control over plant transpiration of water vapor. Effective mitigation of climate change by stabilizing atmospheric carbon dioxide concentrations requires improved understanding of ozone effects on the land carbon sink. Future effects of ozone pollution on the land carbon sink are largely unknown. We apply multiple observational datasets in combination with the Yale Interactive Terrestrial Biosphere (YIBs) model to quantify ozone vegetation damage in the present climatic state and for a broad range of possible futures. YIBs includes a mechanistic ozone damage model that affects both photosynthetic rate and stomatal conductance for low or high ozone plant sensitivity. YIBs is embedded in the NASA GISS ModelE2 global chemistry-climate model to allow a uniquely informed integration of plant physiology, atmospheric chemistry, and climate. The YIBs model has been extensively evaluated using land carbon flux measurements from 145 flux tower sites and multiple satellite products. Chronic ozone exposure in the present day reduces GPP by 11-23%, NPP by 8-16%, stomatal conductance by 8-17% and leaf area index by 2-5% in the summer time eastern United States. Similar response magnitudes are found in Europe but almost doubled damage effects occur in hotspots in eastern China. We investigate future ozone vegetation damage within the context of multiple global change drivers (physical climate change, carbon dioxide fertilization, human energy and agricultural emissions, human land use) at 2050 following the IPCC RCP2.6 and RCP8.5 scenarios. In the RCP8.5 world at 2050, growing season average GPP and NPP are reduced by 20-40% in China and 5-20% in the United States due to the global rise

  20. The forest as a historic source and sink for carbon dioxide; Skogen som historisk kaella respektive saenka foer koldioxid

    Energy Technology Data Exchange (ETDEWEB)

    Kander, A. [Lund Univ. (Sweden). Dept. of Economic History

    1996-06-01

    The aim of the present project is to quantify the changes in the growing stock of timber between 1800 and 1985 in order to find out under which periods and to what extent the forest has served as a source resp. sink for carbon dioxide. These data are compared to the carbon dioxide emissions from combustion of fossil fuels under the same period. Another goal of the project is to find the order of magnitude of the effect of other potential sinks and sources for carbon dioxide. 32 refs, 9 figs, 1 tab

  1. Variability in terrestrial carbon sinks over two decades: Part 2 — Eurasia

    Science.gov (United States)

    Potter, C.; Klooster, S.; Tan, P.; Steinbach, M.; Kumar, V.; Genovese, V.

    2005-12-01

    We have analyzed 17 yr (1982-1998) of net carbon flux predictions from a simulation model based on satellite observations of monthly vegetation cover. The NASA-CASA model was driven by vegetation cover properties derived from the Advanced Very High Resolution Radiometer and radiative transfer algorithms that were developed for the Moderate Resolution Imaging Spectroradiometer (MODIS). We report that although the terrestrial ecosystem sink for atmospheric CO 2 for the Eurasian region has been fairly consistent at between 0.3 and 0.6 Pg C per year since 1988, high interannual variability in net ecosystem production (NEP) fluxes can be readily identified at locations across the continent. Ten major areas of highest variability in NEP were detected: eastern Europe, the Iberian Peninsula, the Balkan states, Scandinavia, northern and western Russia, eastern Siberia, Mongolia and western China, and central India. Analysis of climate anomalies over this 17-yr time period suggests that variability in precipitation and surface solar irradiance could be associated with trends in carbon sink fluxes within such regions of high NEP variability.

  2. Mesoscale ocean fronts enhance carbon export due to gravitational sinking and subduction

    Science.gov (United States)

    Stukel, Michael R.; Aluwihare, Lihini I.; Barbeau, Katherine A.; Chekalyuk, Alexander M.; Goericke, Ralf; Miller, Arthur J.; Ohman, Mark D.; Ruacho, Angel; Song, Hajoon; Stephens, Brandon M.; Landry, Michael R.

    2017-02-01

    Enhanced vertical carbon transport (gravitational sinking and subduction) at mesoscale ocean fronts may explain the demonstrated imbalance of new production and sinking particle export in coastal upwelling ecosystems. Based on flux assessments from 238U:234Th disequilibrium and sediment traps, we found 2 to 3 times higher rates of gravitational particle export near a deep-water front (305 mg Cṡm‑2ṡd‑1) compared with adjacent water or to mean (nonfrontal) regional conditions. Elevated particle flux at the front was mechanistically linked to Fe-stressed diatoms and high mesozooplankton fecal pellet production. Using a data assimilative regional ocean model fit to measured conditions, we estimate that an additional ˜225 mg Cṡm‑2ṡd‑1 was exported as subduction of particle-rich water at the front, highlighting a transport mechanism that is not captured by sediment traps and is poorly quantified by most models and in situ measurements. Mesoscale fronts may be responsible for over a quarter of total organic carbon sequestration in the California Current and other coastal upwelling ecosystems.

  3. Photosynthetic properties of boreal bog plant species and their contribution to ecosystem level carbon sink

    Science.gov (United States)

    Korrensalo, Aino; Hájek, Tomas; Alekseychik, Pavel; Rinne, Janne; Vesala, Timo; Mehtätalo, Lauri; Mammarella, Ivan; Tuittila, Eeva-Stiina

    2016-04-01

    Boreal bogs have a low number of plant species, but a large diversity of growth forms. This heterogeneity might explain the seasonally less varying photosynthetic productivity of these ecosystems compared to peatlands with vegetation consisting of fewer growth forms. The differences in photosynthetic properties within bog species and phases of growing season has not been comprehensively studied. Also the role of different plant species for the ecosystem level carbon (C) sink function is insufficiently known. We quantified the seasonal variation of photosynthetic properties in bog plant species and assessed how this variation accounts for the temporal variation in the ecosystem C sink. Photosynthetic light response of 11 vascular plant and 8 Sphagnum moss species was measured monthly over the growing season of 2013. Based on the species' light response parameters, leaf area development and areal coverage, we estimated the ecosystem level gross photosynthesis rate (PG) over the growing season. The level of upscaled PG was verified by comparing it to the ecosystem gross primary production (GPP) estimate calculated based on eddy covariance (EC) measurements. Although photosynthetic parameters differed within plant species and months, these differences were of less importance than expected for the variation in ecosystem level C sink. The most productive plant species at the ecosystem scale were not those with the highest maximum potential photosynthesis per unit of leaf area (Pmax), but those having the largest areal coverage. Sphagnum mosses had 35% smaller Pmax than vascular plants, but had higher photosynthesis at the ecosystem scale throughout the growing season. The contribution of the bog plant species to the ecosystem level PG differed over the growing season. The seasonal variation in ecosystem C sink was mainly controlled by phenology. Sedge PG had a sharp mid-summer peak, but the PG of evergreen shrubs and Sphagna remained rather stable over the growing season

  4. Carbon allocation, source-sink relations and plant growth: do we need to revise our carbon centric concepts?

    Science.gov (United States)

    Körner, Christian

    2014-05-01

    Since the discovery that plants 'eat air' 215 years ago, carbon supply was considered the largely unquestioned top driver of plant growth. The ease at which CO2 uptake (C source activity) can be measured, and the elegant algorithms that describe the responses of photosynthesis to light, temperature and CO2 concentration, explain why carbon driven growth and productivity became the starting point of all process based vegetation models. Most of these models, nowadays adopt other environmental drivers, such as nutrient availability, as modulating co-controls, but the carbon priority is retained. Yet, if we believe in the basic rules of stoichometry of all life, there is an inevitable need of 25-30 elements other then carbon, oxygen and hydrogen to build a healthy plant body. Plants compete for most of these elements, and their availability (except for N) is finite per unit land area. Hence, by pure plausibility, it is a highly unlikely situation that carbon plays the rate limiting role of growth under natural conditions, except in deep shade or on exceptionally fertile soils. Furthermore, water shortage and low temperature, both act directly upon tissue formation (meristems) long before photosynthetic limitations come into play. Hence, plants will incorporate C only to the extent other environmental drivers permit. In the case of nutrients and mature ecosystems, this sink control of plant growth may be masked in the short term by a tight, almost closed nutrient cycle or by widening the C to other element ratio. Because source and sink activity must match in the long term, it is not possible to identify the hierarchy of growth controls without manipulating the environment. Dry matter allocation to C rich structures and reserves may provide some stoichimetric leeway or periodic escapes from the more fundamental, long-term environmental controls of growth and productivity. I will explain why carbon centric explanations of growth are limited or arrive at plausible answers

  5. The sequestration sink of soot black carbon in the Northern European Shelf sediments

    Science.gov (United States)

    SáNchez-GarcíA, Laura; Cato, Ingemar; Gustafsson, Örjan

    2012-03-01

    To test the hypothesis that ocean margin sediments are a key final repository in the large-scale biogeospheric cycling of soot black carbon (soot-BC), an extensive survey was conducted along the ˜2,000 km stretch of the Swedish Continental Shelf (SCS). The soot-BC content in the 120 spatially distributed SCS sediments was 0.180.130.26% dw (median with interquartile ranges), corresponding to ˜5% of total organic carbon. Using side-scan sonar constraints to estimate the areal fraction of postglacial clay sediments that are accumulation bottoms (15% of SCS), the soot-BC inventory in the SCS mixed surface sediment was estimated at ˜4,000 Gg. Combining this with radiochronological constraints on sediment mass accumulation fluxes, the soot-BC sink on the SCS was ˜300 Gg/yr, which yielded an area-extrapolated estimate for the Northern European Shelf (NES) of ˜1,100 Gg/yr. This sediment soot-BC sink is ˜50 times larger than the river discharge fluxes of soot-BC to these coastal waters, however, of similar magnitude as estimates of atmospheric soot-BC emission from the upwind European continent. While large uncertainties remain regarding the large-scale to global BC cycle, this study combines with two previous investigations to suggest that continental shelf sediments are a major final repository of atmospheric soot-BC. Future progress on the soot-BC cycle and how it interacts with the full carbon cycle is likely to benefit from14C determinations of the sedimentary soot-BC and similar extensive studies of coastal sediment in complementary regimes such as off heavily soot-BC-producing areas in S and E Asia and on the large pan-Arctic shelf.

  6. Large carbon-sink potential by Kyoto forests in Sweden - a case study on willow plantations

    Energy Technology Data Exchange (ETDEWEB)

    Grelle, Achim [Dept. of Ecology, Swedish Univ. of Agricultural Sciences, Upp sala (Sweden)]. e-mail: Achim.Grelle@ekol.slu.se; Aronsson, Paer [Dept. of Crop Prod uction Ecology, Swedish Univ. of Agricultural Sciences, Uppsala (Sweden); Weslien, Per; Klemedtsson, Leif [Dept. of Plant and Environmental Sciences, Gothenburg Univ. ( SE); Lindroth, Anders [Geobiospheric Science Centre, Physical Geography and Eco systems Analysis, Lund Univ., Lund (Sweden)

    2007-11-15

    Fluxes of CO{sub 2} were measured in a 75-ha short-rotation willow plantation at Enkoeping, central Sweden. The plantation was irrigated with wastewater for fertilization and water-filtering purposes. The harvested biomass was used locally for combined heat and power production. The plantation was a sink of ca. 8 tonnes C/ha during 2003, of which ca. 50% was estimated to be attributed to fertilization. Biomass increment by shoot growth was 5 tonnes C/ha during the same year. Below ground carbon allocation was estimated to 3 tonnes C/ha/yr by a model that relates carbon allocation to shoot growth. Thus, the ecosystem carbon balance was closed by these estimations. The carbon uptake by the willow plantation was 5.5 times as high compared to a normally managed spruce forest, but only half as high as from an experimental, well-managed willow plantation in the same region. This illustrates the vast potential of short-rotation willow plantations for CO{sub 2} uptake from the atmosphere.

  7. Factoring out natural and indirect human effects on terrestrial carbon sources and sinks

    Energy Technology Data Exchange (ETDEWEB)

    Canadell, J.G. [Global Carbon Project, CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601 (Australia); Kirschbaum, M.U.F. [Environmental Biology Group, RSBS, Australian National University, GPO Box 475, Canberra, ACT 2601 (Australia); Kurz, W.A. [Natural Resources Canada, Canadian Forest Service, 506 West Burnside Road, Victoria, BC V8Z 1M5 (Canada); Sanz, M.J. [Fundacion CEAM, Parque Tecnologico, Charles H. Darwin 14, 46980 Paterna, Valencia (Spain); Schlamadinger, B. [Joanneum Research, Elisabethstrasse 11, Graz A-8010 (Austria); Yamagata, Y. [Center for Global Environmental Research, National Institute of Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan)

    2007-06-15

    The capacity to partition natural, indirect, and direct human-induced effects on terrestrial carbon (C) sources and sinks is necessary to be able to predict future terrestrial C dynamics and thus their influence on atmospheric CO2 growth. However, it will take a number of years before we can better attribute quantitative estimates of the contribution of various C processes to the net C balance. In a policy context, factoring out natural and indirect human-induced effects on C sources and sinks from the direct human-induced influences, is seen as a requirement of a C accounting approach that establishes a clear and unambiguous connection between human activities and the assignment of C credits and debits. We present options for factoring out various groups of influences including climate variability, CO2 and N fertilization, and legacies from forest management. These are: (1) selecting longer accounting or measurement periods to reduce the effects of inter-annual variability; (2) correction of national inventories for inter-annual variability; (3) use of activity-based accounting and C response curves; (4) use of baseline scenarios or benchmarks at the national level; (5) stratification of the landscape into units with distinct average C stocks. Other, more sophisticated modeling approaches (e.g., demographic models in combination with forest inventories; process-based models) are possible options for future C accounting systems but their complexity and data requirements make their present adoption more difficult in an inclusive international C accounting system.

  8. Mangrove carbon sink. Do burrowing crabs contribute to sediment carbon storage? Evidence from a Kenyan mangrove system

    Science.gov (United States)

    Andreetta, Anna; Fusi, Marco; Cameldi, Irene; Cimò, Filippo; Carnicelli, Stefano; Cannicci, Stefano

    2014-01-01

    Mangrove ecosystems are acknowledged as a significant carbon reservoir, with a potential key role as carbon sinks. Little however is known on sediment/soil capacity to store organic carbon and the impact of benthic fauna on soil organic carbon (SOC) stock in mangrove C-poor soils. This study aimed to investigate the effects of macrobenthos on SOC storage and dynamic in mangrove forest at Gazi Bay (Kenya). Although the relatively low amount of organic carbon (OC%) in these soils, they resulted in the presence of large ecosystem carbon stock comparable to other forest ecosystems. SOC at Gazi bay ranged from 3.6 kg m- 2 in a Desert-like belt to 29.7 kg m- 2 in the Rhizophora belt considering the depth soil interval from 0 cm to 80 cm. The high spatial heterogeneity in the distribution and amount of SOC seemed to be explained by different dominant crab species and their impact on the soil environment. A further major determinant was the presence, in the subsoil, of horizons rich in organic matter, whose dating pointed to their formation being associated with sea level rise over the Holocene. Dating and soil morphological characters proved to be an effective support to discuss links between the strategies developed by macrobenthos and soil ecosystem functioning.

  9. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

    Science.gov (United States)

    Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardgree, Stuart; Strand, Eva

    2013-01-01

    Woody encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p 2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 – 143.6 kg and 0.5 – 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

  10. Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

    Directory of Open Access Journals (Sweden)

    J. Hommeltenberg

    2014-02-01

    Full Text Available This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-alpine region of southern Germany. The sites are separated by only ten kilometers, they share the same formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo rotundata grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies grows on drained and degraded peat (3.4 m. The net ecosystem exchange of CO2 (NEE at both sites has been investigated for two years (July 2010 to June 2012, using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (−130 ± 31 and −300 ± 66 g C m−2 a−1 in the first and second year respectively than the natural bog forest at Schechenfilz (−53 ± 28 and −73±38 g C m−2 a−1. The strong net CO2 uptake can be explained by the high gross primary productivity of the spruces that over-compensates the two times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger LAI of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source, if the whole life-cycle, since forest planting is considered. We determined the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. The estimate resulted in a strong carbon release of +156 t C ha−1 within the last 44 yr, means the spruces would need to grow for another 100 yr, at the current rate, to compensate the peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but consistent carbon sink for decades, which our results suggest is very

  11. Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

    Science.gov (United States)

    Hommeltenberg, J.; Schmid, H. P.; Drösler, M.; Werle, P.

    2014-07-01

    This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-Alpine region of southern Germany. The sites are separated by only 10 km, they share the same soil formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo ssp. rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for 2 years (July 2010-June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (-130 ± 31 and -300 ± 66 g C m-2 a-1 in the first and second year, respectively) than the natural bog forest at Schechenfilz (-53 ± 28 and -73 ± 38 g C m-2 a-1). The strong net CO2 uptake can be explained by the high gross primary productivity of the 44-year old spruces that over-compensates the two-times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger plant area index (PAI) of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source when the whole life-cycle since forest planting is considered. It is important to access this result in terms of the long-term biome balance. To do so, we used historical data to estimate the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. This rough estimate indicates a strong carbon release of +134 t C ha-1 within the last 44 years. Thus, the spruces would need to grow for another 100 years at about the current rate, to compensate the potential peat loss of the former years. In

  12. Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function

    Energy Technology Data Exchange (ETDEWEB)

    Lubowski, Ruben N.; Plantinga, Andrew J.; Stavins, Robert N.

    2001-01-01

    Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration costs are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change.

  13. The economics of including carbon sinks in climate change policy. Evaluating the carbon supply-curve through afforestation in Latin America

    NARCIS (Netherlands)

    Benìtez-Ponce, P.C.

    2003-01-01

    After the inclusion of carbon sinks in the Kyoto Protocol, greenhouse gas mitigation policies should account for abatement measurements in both the energy and forestry sectors. This report deals with the development of a methodology for estimating cost-curves of carbon sequestration with afforestati

  14. Sustainable Materialization of Residues from Thermal Processes into Carbon Sinks (Duurzame omvorming van residuen van thermische processen in koolstofputten)

    OpenAIRE

    Santos, Rafael Mattos dos

    2013-01-01

    Two of the largest and most important waste products from industrial the rmal processes are carbon dioxide gas and waste solid residues. Given th e high financial and environmental burden caused by these waste products , it is urgently desirable to industry and society alike to find a susta inable manner for managing them. The objective of this research project is the production of a carbon sink based on the process of mineral carbo n sequestration that provides a responsible and economical o...

  15. A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches

    Science.gov (United States)

    Jiang, Fei; Chen, Jing; Zhou, Linxi; Ju, Weimin; Zhang, Huifang; Machida, Toshinobu; Ciais, Philippe; Peters, Wouter; Wang, Hengmao; Chen, Baozhang; Liu, Linxin; Zhang, Chunhua; Matsueda, Hidekazu; Sawa, Yousuke

    2016-04-01

    Atmospheric inversions use measurements of atmospheric CO2 gradients to constrain regional surface fluxes. Current inversions indicate a net terrestrial CO2 sink in China between 0.16 and 0.35 PgC/yr. The uncertainty of these estimates is as large as the mean because the atmospheric network historically contained only one high altitude station in China. Here, we revisit the calculation of the terrestrial CO2 flux in China, excluding emissions from fossil fuel burning and cement production, by using two inversions with three new CO2 monitoring stations in China as well as aircraft observations over Asia. We estimate a net terrestrial CO2 uptake of 0.39-0.51 PgC/yr with a mean of 0.45 PgC/yr in 2006-2009. After considering the lateral transport of carbon in air and water and international trade, the annual mean carbon sink is adjusted to 0.35 PgC/yr. To evaluate this top-down estimate, we constructed an independent bottom-up estimate based on ecosystem data, and giving a net land sink of 0.33 PgC/yr. This demonstrates closure between the top-down and bottom-up estimates. Both top-down and bottom-up estimates give a higher carbon sink than previous estimates made for the 1980s and 1990s, suggesting a trend towards increased uptake by land ecosystems in China.

  16. Assessment of climate impacts on the karst-related carbon sink in SW China using MPD and GIS

    Science.gov (United States)

    Zeng, Sibo; Jiang, Yongjun; Liu, Zaihua

    2016-09-01

    Riverine carbon fluxes of some catchments in the world have significantly changed due to contemporary climate change and human activities. As a large region with an extensive karstic area of nearly 7.5 × 105 km2, Southwest (SW) China has experienced dramatic climate changes during recent decades. Although some studies have investigated the karst-related carbon sink in some parts of this region, the importance of climate impacts have not been assessed. This research examined the impacts of recent climate change on the karst-related carbon sink in the SW China for the period 1970-2013, using a modified maximal potential dissolution (MPD) method and GIS. We first analyzed the major determinants of carbonate dissolution at a spatial scale, calculated the total karst-related carbon sink (TCS) and carbon sink fluxes (CSFs) in the SW China karst region with different types of carbonate rocks, and then compared with other methods, and analyzed the causes of CSFs variations under the changed climate conditions. The results show that the TCS in SW China experienced a dramatic change with regional climate, and there was a trend with TCS decreasing by about 19% from 1970s to 2010s. This decrease occurred mostly in Guizhou and Yunnan provinces, which experienced larger decreases in runoff depth in the past 40 years (190 mm and 90 mm, respectively) due to increased air temperature (0.33 °C and 1.04 °C, respectively) and decreased precipitation (156 mm and 106 mm, respectively). The mean value of CSFs in SW China, calculated by the modified MPD method, was approximately 9.36 t C km- 2 a- 1. In addition, there were large differences in CSFs among the provinces, attributed to differences in regional climate and to carbonate lithologies. These spatiotemporal changes depended mainly on hydrological variations (i.e., discharge or runoff depth). This work, thus, suggests that the karst-related carbon sink could respond to future climate change quickly, and needs to be considered in

  17. Global net land carbon sink: Results from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP)

    Science.gov (United States)

    Huntzinger, D. N.; Schwalm, C. R.; Michalak, A. M.; Cook, R. B.; Jacobson, A. R.; Schaefer, K. M.; Dasgupta, A.; Poco, J.

    2013-12-01

    The Multi-scale Synthesis and Model Intercomparison Project (MsTMIP) is a formal model intercomparison effort focused on improving the diagnosis and attribution of carbon exchange at regional and global scales. Here we present results from the terrestrial biospheric models participating in the MsTMIP effort, focusing on global and regional model estimates of the net land carbon sink. When compared to estimates of the residual net land sink inferred from atmospheric CO2 observations (i.e., fossil fuel emission + land use land cover change - atmospheric increase - ocean uptake), MsTMIP models predict, on average, a weaker global net land uptake of carbon. There is a large spread in MsTMIP estimates of the net land sink (e.g., -2.5 to 5.0 Pg C/yr in 2010, where a negative flux represents a net release to the atmosphere). Some models consistently show the land surface as a net source of carbon to the atmosphere, which is inconsistent with the atmospheric record. In addition, we examine how model estimates of the cumulative global net sink diverge over the period 1900 to 2010, and the degree to which model sensitivity to forcing factors and fundamental differences in model formulation contribute to this divergence. We link differences in estimates of the cumulative land sink back to each model's sensitivity to key forcing factors including climate variability, CO2 fertilization, nitrogen limitation, and land cover / land-use change. For example, the strength of carbon uptake in most models appears to be strongly coupled with atmospheric CO2 concentrations (CO2 fertilization effect). The strength of this relationship, however, varies across models with some models exhibiting a very strong CO2 fertilization effect (e.g., ORCHIDEE), while others not so (e.g., CLM). To inform the comparison across models, structural differences (i.e., which processes are included and how those processes are parameterized) among the participating models are evaluated using hierarchical

  18. Integrated Behavior of Carbon and Copper Alloy Heat Sink Under Different Heat Loads and Cooling Conditions

    Institute of Scientific and Technical Information of China (English)

    Li Hua; Li Jiangang; Chen Junling; Hu Jiansheng

    2005-01-01

    An actively water-cooled limiter has been designed for the long pulse operation of an HT-7 device, by adopting an integrated structure-doped graphite and a copper alloy heat sink with a super carbon sheet serving as a compliant layer between them. The behaviors of the integrated structure were evaluated in an electron beam facility under different heat loads and cooling conditions. The surface temperature and bulk temperature distribution were carefully measured by optical pyrometers and thermocouples under a steady state heat flux of 1 to 5 MW/m2 and a water flow rate of 3 m3/h, 4.5 m3/h and 6 m3/h, respectively. It was found that the surface temperature increased rapidly with the heat flux rising, but decreased only slightly with the water flow rate rising. The surface temperature reached approximately 1200℃ at 5 MW/m2 of heat flux and 6 ms/h of water flow. The primary experimental results indicate that the integrated design meets the requirements for the heat expelling capacity of the HT-7 device. A set of numerical simulations was also completed, whose outcome was in good accord with the experimental results.

  19. Effects of solar dimming and brightening on the terrestrial carbon sink

    Science.gov (United States)

    Mercado, L.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Wild, M.; Cox, P. M.

    2009-04-01

    Plant photosynthesis increases with solar radiation. Recent studies have shown that photosynthesis is more efficient under diffuse light conditions (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). Changes in cloud cover and atmospheric aerosol loadings from either volcanic and anthropogenic sources, modify the total radiation reaching the surface and the fraction of this radiation which is diffuse, with uncertain overall effects on plant productivity and the global land carbon sink. A decrease in total solar radiation (Liepert, 2002, Stanhill and Cohen, 2001, Wild et al., 2005) has been observed at the Earth surface over the 1950-1990 period, called solar dimming. Such dimming gradually started to transform into brightening in some regions of the world since the late 1980s (Wild et al. 2005). The effect of these changes in total solar radiation and associated changes in diffuse radiation and diffuse fraction on the land biosphere has not yet been accounted for in global carbon cycle simulations because such models lack the mechanism that includes the diffuse irradiance effects on photosynthesis In this study we estimate the total impact of variations in clouds and atmospheric aerosols on the land carbon sink using a global land carbon cycle model modified to account for the effects of variations in both direct and diffuse radiation on canopy photosynthesis (Mercado et al., 2007) during the global dimming and brightening period. References Gu L.H., Baldocchi D.D., Wofsy S.C., Munger J.W., Michalsky J.J., Urbanski S.P. & Boden T.A. (2003) Response of a deciduous forest to the Mount Pinatubo eruption: Enhanced photosynthesis. Science, 299, 2035-2038. Liepert B.G. (2002) Observed reductions of surface solar radiation at sites in the United States and worldwide from 1961 to 1990. 29, 1421. Mercado L.M., Huntingford C., Gash J.H.C., Cox P.M. & Jogireddy V. (2007) Improving the representation of radiation interception and

  20. Value of Carbon Sink:Concept and Evaluation%碳汇价值的形成和评价

    Institute of Scientific and Technical Information of China (English)

    谢高地; 李士美; 肖玉; 祁悦

    2011-01-01

    In the context of carbon emission reduction, how to evaluate the benefit of carbon storage and sequestration was theoretically and practically critical. In this study, we investigated the linkage between global climate change and carbon emission and linkage between carbon emission and economic system, and found out the carbon emission permits was scarce, which constituted the realistic basis of carbon sink utility value. We reviewed components of the economic value of carbon sink and their measurement methods, and pointed out the concept difference between carbon storage and carbon sequestration. We also identified the mechanisms for fulfilling the economic value of carbon sink and classified them into three types, which were carbon trade, carbon tax and cost of carbon sequestration project. Based on the price of carbon sequestration from these three types of mechanisms, the economic value of carbon sequestration could be fulfilled with economic compensation.%在碳减排形势下,如何评价固碳收益价值具有重要的理论与实践意义.论文首先从全球气候变化与碳排放的关联、碳排放与现有经济体系的关联、碳排放空间成为稀缺资源三个方面论证了碳汇效用价值形成的现实基础.然后评述了碳汇价值的构成与度量方法,指出了碳固定与碳蓄积价值的内涵差异.继而总结了碳汇价值的实现机制,认为可以通过碳交易、碳税和固碳项目实际成本3种机制实现碳价格,并在此基础上通过补偿实现碳汇价值.

  1. Assessing the carbon sink of afforestation with the Carbon Budget Model at the country level: an example for Italy

    Directory of Open Access Journals (Sweden)

    Pilli R

    2015-08-01

    Full Text Available In the context of the Kyoto Protocol, the mandatory accounting of Afforestation and Reforestation (AR activities requires estimating the forest carbon (C stock changes for any direct human-induced expansion of forest since 1990. We used the Carbon Budget Model (CBM to estimate C stock changes and emissions from fires on AR lands at country level. Italy was chosen because it has one of the highest annual rates of AR in Europe and the same model was recently applied to Italy’s forest management area. We considered the time period 1990-2020 with two case studies reflecting different average annual rates of AR: 78 kha yr-1, based on the 2013 Italian National Inventory Report (NIR, official estimates, and 28 kha yr-1, based on the Italian Land Use Inventory System (IUTI estimates. We compared these two different AR rates with eight regional forest inventories and three independent local studies. The average annual C stock change estimated by CBM, excluding harvest or natural disturbances, was equal to 1738 Gg C yr-1 (official estimates and 630 Gg C yr-1 (IUTI estimates. Results for the official estimates are consistent with the estimates reported by Italy to the KP for the period 2008-2010; for 2011 our estimates are about 20% higher than the country’s data, probably due to different assumptions on the fire disturbances, the AR rate and the dead wood and litter pools. Furthermore, our analysis suggests that: (i the impact on the AR sink of different assumptions of species composition is small; (ii the amount of harvest provided by AR has been negligible for the past (< 3% and is expected to be small in the near future (up to 8% in 2020; (iii forest fires up to 2011 had a small impact on the AR sink (on average, < 100 Gg C yr-1. Finally the comparison of the historical AR rates reported by NIR and IUTI with other independent sources gives mixed results: the regional inventories support the AR rates reported by the NIR, while some local studies

  2. Could 4 degrees warming change Arctic tundra from carbon sink to carbon source?

    Science.gov (United States)

    Torn, M. S.; Abramoff, R. Z.; Chafe, O.; Curtis, J. B.; Smith, L. J.; Wullschleger, S. D.

    2015-12-01

    We have set up a controlled, active warming experiment in permafrost tundra on the North Slope of Alaska. The aim of this micro-warming experiment is to investigate the direct effect of soil warming on microbial decomposition of soil organic matter. We are testing the feasibility of small, short-term, in situ warming that can be run off batteries for distributed deployment and that preserves plant-soil relations and natural variability in wind, temperature, and precipitation. Based on preliminary results, the approach looks promising. One resistance heater cable per plot (25 cm diameter plots) was inserted vertically to 50 cm, spanning the full active layer (maximum thaw depth was 40 cm in 2014). Heaters were turned on August 1, 2015, and heated plots reached the 4ºC warming target within 1-3 days. We are measuring soil microclimate, thaw depth, CO2 and CH4 fluxes, and 14CO2, and microbial composition, as part of the DOE Next Generation Ecosystem Experiments (NGEE-Arctic). Ecosystem respiration increased immediately in the heated plots, and net ecosystem exchange under clear chambers changed from net uptake to net CO2 source in two of the four plots. CH4 flux shifted toward reduced net emissions or greater net uptake in all plots. These rapid responses demonstrate direct changes in decomposition without complications from microbial acclimation, altered community structure or changes in substrate availability. However, future Arctic tundra carbon balance will depend on both short term and long term microbial responses, as well as the links between warming, decomposition, nitrogen mineralization, and plant growth. Thus, we envision that distributed micro-warming plots could be combined with new approaches to aboveground passive warming being developed in NGEE, gradient studies, and modeling.

  3. Functional Diversity of Boreal Bog Plant Species Decreases Seasonal Variation of Ecosystem Carbon Sink Function

    Science.gov (United States)

    Korrensalo, A.

    2015-12-01

    Species diversity has been found to decrease the temporal variance of productivity of a plant community, and diversity in species responses to environmental factors seems to make a plant community more stable in changing conditions. Boreal bogs are nutrient poor peatland ecosystems where the number of plant species is low but the species differ greatly in their growth form. In here we aim to assess the role of the variation in photosynthesis between species for the temporal variation in ecosystem carbon sink function. To quantify the photosynthetic properties and their seasonal variation for different bog plant species we measured photosynthetic parameters and stress-inducing chlorophyll fluorescence of vascular plant and Sphagnum moss species in a boreal bog over a growing season. We estimated monthly gross photosynthesis (PG) of the whole study site based on species level light response curves and leaf area development. The estimated PG was further compared with a gross primary production (GPP) estimate measured by eddy covariance (EC) technique. The sum of upscaled PG estimates agreed well with the GPP estimate measured by the EC technique. The contributions of the species and species groups to the ecosystem level PG changed over the growing season. The sharp mid-summer peak in sedge PG was balanced by more stable PG of evergreen shrubs and Sphagna. Species abundance rather than differences in photosynthetic properties between species and growth forms determined the most productive plants on the ecosystem scale. Sphagna had lower photosynthesis and clorophyll fluorescence than vascular plants but were more productive on the ecosystem scale throughout the growing season due to their high areal coverage. These results show that the diversity of growth forms stabilizes the seasonal variation of the ecosystem level PG in an ombrotrophic bog ecosystem. This may increase the resilience of the ecosystem to changing environmental conditions.

  4. Inter-annual variability of the carbon dioxide oceanic sink south of Tasmania

    Directory of Open Access Journals (Sweden)

    A. V. Borges

    2007-10-01

    Full Text Available We compiled a large data-set from 22 cruises spanning from 1991 to 2003, of the partial pressure of CO2 (pCO2 in surface waters over the continental shelf (CS and adjacent open ocean (43° to 46° S; 145° to 150° E, south of Tasmania. Sea surface temperature (SST anomalies (as intense as 2°C are apparent in the subtropical zone (STZ and subAntarctic zone (SAZ. These SST anomalies also occur on the CS, and seem to be related to large-scale coupled atmosphere-ocean oscillations. Anomalies of pCO2 normalized to a constant temperature are negatively related to SST anomalies. A depressed winter-time vertical input of dissolved inorganic carbon (DIC during phases of positive SST anomalies, related to a poleward shift of westerly winds, and a concomitant local decrease in wind stress are the likely cause of the negative relationship between pCO2 and SST anomalies. The observed trend is an increase of the sink for atmospheric CO2 associated with positive SST anomalies, although strongly modulated by inter-annual variability of wind speed. Assuming that phases of positive SST anomalies are indicative of the future evolution of regional ocean biogeochemistry under global warming, we show using a purely observational based approach that some provinces of the Southern Ocean could provide a potential negative feedback on increasing atmospheric CO2.

  5. Inter-annual variability of the carbon dioxide oceanic sink south of Tasmania

    Directory of Open Access Journals (Sweden)

    A. V. Borges

    2008-02-01

    Full Text Available We compiled a large data-set from 22 cruises spanning from 1991 to 2003, of the partial pressure of CO2 (pCO2 in surface waters over the continental shelf (CS and adjacent open ocean (43° to 46° S; 145° to 150° E, south of Tasmania. Climatological seasonal cycles of pCO2 in the CS, the subtropical zone (STZ and the subAntarctic zone (SAZ are described and used to determine monthly pCO2 anomalies. These are used in combination with monthly anomalies of sea surface temperature (SST to investigate inter-annual variations of SST and pCO2. Monthly anomalies of SST (as intense as 2°C are apparent in the CS, STZ and SAZ, and are indicative of strong inter-annual variability that seems to be related to large-scale coupled atmosphere-ocean oscillations. Anomalies of pCO2 normalized to a constant temperature are negatively related to SST anomalies. A reduced winter-time vertical input of dissolved inorganic carbon (DIC during phases of positive SST anomalies, related to a poleward shift of westerly winds, and a concomitant local decrease in wind stress is the likely cause of the negative relationship between pCO2 and SST anomalies. The observed pattern is an increase of the sink for atmospheric CO2 associated with positive SST anomalies, although strongly modulated by inter-annual variability of wind speed. Assuming that phases of positive SST anomalies are indicative of the future evolution of regional ocean biogeochemistry under global warming, we show using a purely observational based approach that some provinces of the Southern Ocean could provide a potential negative feedback on increasing atmospheric CO2.

  6. Strengthening Carbon Sinks in Urban Soils to Mitigate and Adapt to Climate Change (Invited)

    Science.gov (United States)

    Lorenz, K.

    2010-12-01

    long industrial history and devastations during World War II. In most surface soils in Stuttgart, however, OM was dominated by plant litter derived compounds but in one urban soil anthropogenic OM and black carbon (BC) dominated soil organic carbon (SOC) as indicated by bloch decay solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Artifacts such as municipal solid waste, construction waste, and fragments of charcoal, coal and glass were also found in urban forest soil profiles to 1-m depth in Columbus, OH. To this depth, about 150 Mg SOC ha-1 were stored and, thus, more than in urban forest soils of Baltimore, MD, and New York City, NY. However, the contribution of litter derived vs. artifact derived OM compounds such as BC has not been assessed for urban soils in the U.S.. In summary, studies on biogeochemical cycles in urban ecosystems must include the entire soil profile as anthropogenic activities may create Technosols with properties not encountered in soils of natural ecosystems. As urban ecosystems are major sources of atmospheric carbon dioxide (CO2), Technosols may be tailor-made to imitate natural soils with high SOC pools and long carbon mean residence times. Thus, the C sink in urban soils must be strengthened to mitigate and adapt urban ecosystems to abrupt climate change.

  7. LIFE CLIMATREE project: A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas

    Science.gov (United States)

    Stergiou, John; Tagaris, Efthimios; -Eleni Sotiropoulou, Rafaella

    2016-04-01

    Climate Change Mitigation is one of the most important objectives of the Kyoto Convention, and is mostly oriented towards reducing GHG emissions. However, carbon sink is retained only in the calculation of the forests capacity since agricultural land and farmers practices for securing carbon stored in soils have not been recognized in GHG accounting, possibly resulting in incorrect estimations of the carbon dioxide balance in the atmosphere. The agricultural sector, which is a key sector in the EU, presents a consistent strategic framework since 1954, in the form of Common Agricultural Policy (CAP). In its latest reform of 2013 (reg. (EU) 1305/13) CAP recognized the significance of Agriculture as a key player in Climate Change policy. In order to fill this gap the "LIFE ClimaTree" project has recently founded by the European Commission aiming to provide a novel method for including tree crop cultivations in the LULUCF's accounting rules for GHG emissions and removal. In the framework of "LIFE ClimaTree" project estimation of carbon sink within EU through the inclusion of the calculated tree crop capacity will be assessed for both current and future climatic conditions by 2050s using the GISS-WRF modeling system in a very fine scale (i.e., 9km x 9km) using RCP8.5 and RCP4.5 climate scenarios. Acknowledgement: LIFE CLIMATREE project "A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas" (LIFE14 CCM/GR/000635).

  8. Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink

    Directory of Open Access Journals (Sweden)

    A. Lohila

    2011-11-01

    Full Text Available Drainage for forestry purposes increases the depth of the oxic peat layer and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O change: due to the accelerated decomposition of peat in the presence of oxygen, drained peatlands are generally considered to lose peat carbon (C. We measured CO2 exchange with the eddy covariance (EC method above a drained nutrient-poor peatland forest in southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net CO2 uptake from the atmosphere. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1 and a small source of N2O (0.10 g N2O m−2 yr−1. Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (175 ± 35 g C m−2 was significantly lower than the accumulation observed by the flux measurement (240 ± 30 g C m−2, about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown by EC measurements to occur in a forestry-drained peatland. Our results suggest that forestry

  9. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    Science.gov (United States)

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  10. A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink

    DEFF Research Database (Denmark)

    Landschützer, P.; Gruber, N.; Bakker, D.C.E.;

    2013-01-01

    –18° N, 0.11 ± 0.07 Pg C yr–1), and uptake in the subtropical/temperate South Atlantic south of 18° S (–0.16 ± 0.06 Pg C yr–1), consistent with recent studies. We find the strongest seasonal variability of the CO2 flux in the temperature driven subtropical North Atlantic, with uptake in winter...... poleward of 40° N, but many other parts of the North Atlantic increased more slowly, resulting in a barely changing Atlantic carbon sink north of the equator (–0.007 Pg C yr–1 decade–1). Surface ocean pCO2 was also increasing less than that of the atmosphere over most of the Atlantic south of the equator......, leading to a substantial trend toward a stronger CO2 sink for the entire South Atlantic (–0.14 Pg C yr–1 decade–1). The Atlantic carbon sink varies relatively little on inter-annual time-scales (±0.04 Pg C yr–1; 1σ)...

  11. 关于碳汇统计测度的研究%Study on the Statistics Measurement of Carbon Sink

    Institute of Scientific and Technical Information of China (English)

    王佐仁; 肖建勇

    2013-01-01

    Climate change is caused by the increase of greenhouse gases in which the carbon dioxide occupied the main body in the atmosphere .CO2 plays a major role to the global greenhouse effect although it is smaller than other gases .This paper studies the absorption and fixed of CO 2 from the perspective of carbon sink on CO2 emission and absorption .At the same time ,it points out :marine carbon sink function of the system and land carbon sink function of the system have the same important role to absorb and fixation of CO2 .%  气候变化主要是大气中以CO2为主体的温室气体的增加所引起,虽然CO2温室效应强度比其他气体小,但其构成了温室气体最主要的成分,对全球温室效应起着主要的作用。文章主要从碳汇的角度对CO2排放与吸收进行统计测量,分析了森林碳汇、湿地碳汇和海洋碳汇的测定方法,同时指出:海洋系统的碳汇功能与陆地系统的碳汇功能一样,对CO2的吸收固定有着重要的作用。

  12. Inferring marine sinks and sources of monohalomethanes from their carbon stable isotope composition

    Science.gov (United States)

    Bahlmann, Enno; Weinberg, Ingo; Eckhardt, Tim; Seifert, Richard; Michaelis, Walter

    2013-04-01

    Within the last years much progress in quantifying the global emissions of various halocarbons has been made. However, the current emission estimates are still assigned with large uncertainties due to the inevitably large spatial and temporal variability in observed halocarbon mixing ratios and fluxes. An improved understanding of the biogeochemical controls of the production - destruction equilibrium may substantially reduce these uncertainties and is of vital importance to address potential future changes. The δ13C values of monohalomethanes vary sensitively towards changes of both, sources and sinks making them a valuable tool to assess concurrent production and degradation processes. Here we report carbon isotope ratios for chloromethane (CH3Cl) and bromomethane (CH3Br) in background air and coastal and open ocean surface waters. The samples were taken during five sampling campaigns between September 2010 and July 2012 with the sample locations spanning from 10°N to 60°N Our results show an enrichment by about 4‰ for chloromethane in marine air masses (-36‰) as compared to continental air masses (-40‰) corroborating earlier findings. This enrichment is supported by the observation of even more enriched chloromethane in the ocean surface waters averaging -28‰ for the subtropical North East Atlantic. For bromomethane, our data show an even more pronounced enrichment by 16‰ from -44‰ in continental air masses to -28‰ in marine air masses. These isotopic differences can be attributed to the air sea exchange of these compounds in concert with the production - decomposition dynamics in surface oceans. Hydrolysis, assigned with an ɛ of 45‰, is regarded as the most important degradation process for chloromethane in surface oceans. Bromomethane from both, intrinsic sources and from the atmosphere, is known to be rapidly degraded in marine surface waters by biotic and abiotic processes. The abiotic degradation due to hydrolysis and transhalogenation

  13. Study visit carbon sinks Peugeot. Evaluation after 5 years and perspectives; Visite d'etude Puits de Carbone Peugeot. Bilan a 5 ans et perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Grosso, M.; Sao Nicolau, F

    2005-07-01

    In the framework of its project of the climatic change control, PSA Peugeot Citroen, decided to involve in the decrease of the carbon dioxide emissions. In parallel to the vehicles consumption decrease and the biofuels utilization, the group developed since 5 years a pilot project of carbon sink. This project aims to study the impact of a trees plantation, at a big scale, on the atmospheric carbon dioxide fixation. This document is a first evaluation after the phase of trees plantation. (A.L.B.)

  14. Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink

    Directory of Open Access Journals (Sweden)

    J. R. Melton

    2014-02-01

    Full Text Available Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs and use their vegetation attributes in calculations of the energy and water balance as well as to investigate the terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models is represented using different approaches with the "composite" and "mosaic" approaches being the two end-members. The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2 coupled to the Canadian Land Surface Scheme (CLASS v 3.6. In the composite (single-tile approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc. that are common to all PFTs. In the mosaic (multi-tile approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005 show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC effects differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same

  15. A sink for atmospheric carbon dioxide in the northeast Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; Naqvi, S.W; George, M.D; Jayakumar, D

    dioxide (TCO sub(2)) and pCO sub(2) distributions in surface waters. Low pCO sub(2) levels occur within the low-salinity zones, with a large area in the northwestern bay acting as a sink for atmospheric CO sub(2) . Only a part of the observed pCO sub(2...

  16. Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink

    Directory of Open Access Journals (Sweden)

    A. Lohila

    2011-06-01

    Full Text Available Drainage for forestry purposes changes the conditions in the peat and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O are likely to change: due to the accelerated decomposition of oxic peat, drained peatlands are generally considered to loose peat carbon (C. We measured CO2 exchange with the eddy covariance (EC method above a drained nutrient-poor peatland forest in Southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5 week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 g CO2 m−2 yr−1 in the calendar year 2005, varying from −810 to −900 g CO2 m−2 yr−1 during the 16 month period under investigation. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1 and a small source of N2O (0.10 g N2O m−2 yr−1. Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (550 g CO2 m−2 was significantly less than the net exchange of CO2, about 300 g CO2 m−2 yr−1 (~80 g C m−2 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown, by EC measurements, to occur in a drained

  17. Impact of Changes in Diffuse Radiation on the Global Land Carbon Sink, 1901-2100

    Science.gov (United States)

    Mercado, L.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Wild, M.; Cox, P. M.

    2009-04-01

    Recent observational and theoretical studies have shown that changes in surface radiation that lead to increasing diffuse surface irradiance, enhance plant photosynthesis (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). Solar radiation reaching the land surface has changed over the industrial era due to aerosols emitted from volcanoes and various anthropogenic sources (Kvalevag and Myhre, 2007). Such changes in total surface radiation are accompanied by changes in direct and diffuse surface solar radiation. Current global climate-carbon models do include the effects of changes in total surface radiation on the land biosphere but neglect the positive effects of increasing diffuse fraction on plant photosynthesis. In this study we estimate for the first time, the impact of variations in diffuse fraction on the land carbon sink using a global model (Mercado et al., 2007) modified to account for the effects of variations in both direct and diffuse radiation on canopy photosynthesis. We use meteorological forcing from the Climate Research Unit Data set. Additionally short wave and photosynthetic active radiation are reconstructed from the Hadley centre climate model, which accounts for the scattering and absorption of light by tropospheric and stratospheric aerosols and change in cloud properties due to indirect aerosol effects. References Gu L.H., Baldocchi D.D., Wofsy S.C., Munger J.W., Michalsky J.J., Urbanski S.P. & Boden T.A. (2003) Response of a deciduous forest to the Mount Pinatubo eruption: Enhanced photosynthesis. Science, 299, 2035-2038. M. M. Kvalevag and G. Myhre, J. Clim. 20, 4874 (2007). Mercado L.M., Huntingford C., Gash J.H.C., Cox P.M. & Jogireddy V. (2007) Improving the representation of radiation interception and photosynthesis for climate model applications. Tellus Series B-Chemical and Physical Meteorology, 59, 553-565. Niyogi D., Chang H.I., Saxena V.K., Holt T., Alapaty K., Booker F., Chen F., Davis K

  18. Assessment of the soil organic carbon sink in a project for the conversion of farmland to forestland: a case study in Zichang county, Shaanxi, China.

    Directory of Open Access Journals (Sweden)

    Lan Mu

    Full Text Available The conversion of farmland to forestland not only changes the ecological environment but also enriches the soil with organic matter and affects the global carbon cycle. This paper reviews the influence of land use changes on the soil organic carbon sink to determine whether the Chinese "Grain-for-Green" (conversion of farmland to forestland project increased the rate of SOC content during its implementation between 1999 and 2010 in the hilly and gully areas of the Loess Plateau in north-central China. The carbon sink was quantified, and the effects of the main species were assessed. The carbon sink increased from 2.26×106 kg in 1999 to 8.32×106 kg in 2010 with the sustainable growth of the converted areas. The black locust (Robinia pseudoacacia L. and alfalfa (Medicago sativa L. soil increased SOC content in the top soil (0-100 cm in the initial 7-yr period, while the sequestration occurred later (>7 yr in the 100-120 cm layer after the "Grain-for-Green" project was implemented. The carbon sink function measured for the afforested land provides evidence that the Grain-for-Green project has successfully excavated the carbon sink potential of the Shaanxi province and served as an important milestone for establishing an effective organic carbon management program.

  19. Forest biomass carbon sinks in East Asia, with special reference to the relative contributions of forest expansion and forest growth.

    Science.gov (United States)

    Fang, Jingyun; Guo, Zhaodi; Hu, Huifeng; Kato, Tomomichi; Muraoka, Hiroyuki; Son, Yowhan

    2014-06-01

    Forests play an important role in regional and global carbon (C) cycles. With extensive afforestation and reforestation efforts over the last several decades, forests in East Asia have largely expanded, but the dynamics of their C stocks have not been fully assessed. We estimated biomass C stocks of the forests in all five East Asian countries (China, Japan, North Korea, South Korea, and Mongolia) between the 1970s and the 2000s, using the biomass expansion factor method and forest inventory data. Forest area and biomass C density in the whole region increased from 179.78 × 10(6) ha and 38.6 Mg C ha(-1) in the 1970s to 196.65 × 10(6) ha and 45.5 Mg C ha(-1) in the 2000s, respectively. The C stock increased from 6.9 Pg C to 8.9 Pg C, with an averaged sequestration rate of 66.9 Tg C yr(-1). Among the five countries, China and Japan were two major contributors to the total region's forest C sink, with respective contributions of 71.1% and 32.9%. In China, the areal expansion of forest land was a larger contributor to C sinks than increased biomass density for all forests (60.0% vs. 40.0%) and for planted forests (58.1% vs. 41.9%), while the latter contributed more than the former for natural forests (87.0% vs. 13.0%). In Japan, increased biomass density dominated the C sink for all (101.5%), planted (91.1%), and natural (123.8%) forests. Forests in South Korea also acted as a C sink, contributing 9.4% of the total region's sink because of increased forest growth (98.6%). Compared to these countries, the reduction in forest land in both North Korea and Mongolia caused a C loss at an average rate of 9.0 Tg C yr(-1), equal to 13.4% of the total region's C sink. Over the last four decades, the biomass C sequestration by East Asia's forests offset 5.8% of its contemporary fossil-fuel CO2 emissions.

  20. The Primary Research on Industrialization of Forest Carbon Sinks%森林碳汇产业化初探

    Institute of Scientific and Technical Information of China (English)

    洪玫

    2011-01-01

    The forest carbon sinks play an important role in controlling the Greenhouse Gas emissions. Industrialization of forest carbon sinks will be helpful to attract more and more enterprises to step into afforestation, reforestation and technology development for improvement of forest management. That will create a sustainable situation that governments, NGO and corporations join together. Now the Forest Carbon Offset Market has emerged. Although some obstacles exist, it has large development potential.%森林碳汇对于控制全球温室气体排放具有重要的作用,森林碳汇产业化有助于吸引更多企业从事造林、再造林和改善森林经营管理相关的技术开发和经营,从而形成政府、非盈利组织、企业共同参与的可持续发展的良好局面.目前,森林碳汇市场交易已经初步形成,虽然还存在一些阻碍森林碳汇交易进一步扩大的因素,但发展潜力巨大.

  1. Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink-Rise system, north Florida, USA

    Science.gov (United States)

    Jin, Jin; Zimmerman, Andrew R.; Moore, Paul J.; Martin, Jonathan B.

    2014-03-01

    Spatiotemporal variations in dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major ions concentrations and other geochemical parameters including stable carbon isotopes of DIC (δ13CDIC), were measured in surface water and deep and shallow well water samples of the Santa Fe River Sink-Rise eogenetic karst system, north Florida, USA. Three end-member water sources were identified: one DOC-rich/DIC-poor/δ13CDIC-depleted, one DOC-poor/DIC-rich/δ13CDIC-enriched, and one enriched in major ions. Given their spatiotemporal distributions, they were presumed to represent soil water, upper aquifer groundwater, and deep aquifer water sources, respectively. Using assumed ratios of Na+, Cl, and SO42- for each end-member, a mixing model calculated the contribution of each water source to each sample. Then, chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations. In general, carbonate mineral dissolution occurred throughout the Sink-Rise system, surface waters were net autotrophic and the subsurface was in metabolic balance, i.e., no net DOC or DIC production or consumption. However, there was evidence for chemolithoautotrophy, perhaps by hydrogen oxidizing microbes, at some deep aquifer sites. Mineralization of this autochthonous natural dissolved organic matter (NDOM) led to localized carbonate dissolution as did surface water-derived NDOM supplied to shallow well sites during the highest flow periods. This study demonstrates linkages between hydrology, abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality, karst morphologic evolution, and hydrogeologic projects such as aquifer storage and recovery in karst systems.

  2. Bridging Political Expectations and Scientific Limitations in Climate Risk Management. On the Uncertain Effects of International Carbon Sink Policies

    Energy Technology Data Exchange (ETDEWEB)

    Loevbrand, E. [Environmental Science Section, Department of Biology and Environmental Science, Kalmar University, SE-391 82 Kalmar (Sweden)

    2004-12-01

    Despite great advances in carbon cycle research during the past decade the climatic impact of terrestrial ecosystems is still highly uncertain. Although contemporary studies suggest that the terrestrial biosphere has acted as a net sink to atmospheric carbon during the past two decades, the future role of terrestrial carbon pools is most difficult to foresee. When land use change and forestry activities were included into the Kyoto Protocol in 1997, the requirements for scientific precision increased significantly. At the same time the political expectations of carbon sequestration as climate mitigation strategy added uncertainties of a social kind to the study of land-atmosphere carbon exchange that have been difficult to address by conventional scientific methods. In this paper I explore how the failure to take into account the effects of direct human activity in scientific projections of future terrestrial carbon storage has resulted in a simplified appreciation of the risks embedded in a global carbon sequestration scheme. I argue that the social limits to scientific analysis must be addressed in order to accommodate these risks in future climate governance and to enable continued scientific authority in the international climate regime.

  3. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    Potter, C.; Klooster, S.; Huete, A.; Genovese, V.; Bustamante, M.; Ferreira, L. Guimaraes; deOliveira, R. C., Jr.; Zepp, R.

    2009-01-01

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Net ecosystem production (NEP) flux for atmospheric CO2 in the region for these years was estimated. Consistently high carbon sink fluxes in terrestrial ecosystems on a yearly basis were found in the western portions of the states of Acre and Rondonia and the northern portions of the state of Par a. These areas were not significantly impacted by the 2002-2003 El Nino event in terms of net annual carbon gains. Areas of the region that show periodically high carbon source fluxes from terrestrial ecosystems to the atmosphere on yearly basis were found throughout the state of Maranhao and the southern portions of the state of Amazonas. As demonstrated though tower site comparisons, NEP modeled with monthly MODIS Enhanced Vegetation Index (EVI) inputs closely resembles the measured seasonal carbon fluxes at the LBA Tapajos tower site. Modeling results suggest that the capacity for use of MODIS Enhanced Vegetation Index (EVI) data to predict seasonal uptake rates of CO2 in Amazon forests and Cerrado woodlands is strong.

  4. Using continental observations in global atmospheric inversions of CO{sub 2}: North American carbon sources and sinks

    Energy Technology Data Exchange (ETDEWEB)

    Butler, M.P.; Davis, K.J. (Dept. of Meteorology, Pennsylvania State Univ., University Park, PA 16802 (United States)); Denning, A.S. (Dept. of Atmospheric Science, Colorado State Univ., Fort Collins, CO (United States)); Kawa, S.R. (NASA Goddard Space Flight Center, Greenbelt, MD (United States))

    2010-11-15

    We evaluate North American carbon fluxes using a monthly global Bayesian synthesis inversion that includes well-calibrated carbon dioxide concentrations measured at continental flux towers. We employ the NASA Parametrized Chemistry Tracer Model (PCTM) for atmospheric transport and a TransCom-style inversion with subcontinental resolution. We subsample carbon dioxide time series at four North American flux tower sites for mid-day hours to ensure sampling of a deep, well-mixed atmospheric boundary layer. The addition of these flux tower sites to a global network reduces North America mean annual flux uncertainty for 2001-2003 by 20% to 0.4 Pg C/yr compared to a network without the tower sites. North American flux is estimated to be a net sink of 1.2 +- 0.4 Pg C/yr which is within the uncertainty bounds of the result without the towers. Uncertainty reduction is found to be local to the regions within North America where the flux towers are located, and including the towers reduces covariances between regions within North America. Mid-day carbon dioxide observations from flux towers provide a viable means of increasing continental observation density and reducing the uncertainty of regional carbon flux estimates in atmospheric inversions.

  5. A source-to-sink perspective on the mobilization, transport, and burial of organic carbon following the 2008 Sichuan earthquake

    Science.gov (United States)

    West, A.; Li, G.; Hammond, D. E.; Jin, Z.

    2012-12-01

    The mobilization and fluvial transport of organic carbon is one of the most important geochemical legacies of landslides triggered by extreme events such as major floods or earthquakes. While there is some information about the quantity of carbon carried by rivers under varying flow regimes, and even in the aftermath of single large events, there is little source-to-sink information about the transfer of this carbon through river systems into depositional centers, and about the geochemical transformations following deposition. These processes may be distinct in the aftermath of extreme events because of the association of organic carbon transport with high clastic sediment loads. In this study, we use the legacy of the 2008 Mw 7.9 Wenchuan Earthquake in Sichuan, China, to explore the mobilization, transport, and ultimate fate of organic carbon associated with co-seismic and post-seismic landslides. We focus on Zipingpu Reservoir, which serves as a trap for material carried by the Min Jiang river that drains the epicentral region most dramatically affected by landslides. We use revised landslide and biomass maps to quantify total organic carbon mobilized from hillslopes within the reservoir catchment area. We have collected sediment cores from the reservoir itself, and together with estimates of sedimentation rates constrained by short-lived radionuclide abundances, we construct a budget for the carbon transport into the reservoir based on analyses of sediment solid phase organic C concentrations and isotope ratios. Post-depositional diagenetic alteration is quantified using pore water profiles, including DIC concentration, carbon isotope compositions, and the isotopic composition of methane collected both in-situ from pore waters, and associated with actively bubbling methane seeps.

  6. A shift of thermokarst lakes from carbon sources to sinks during the Holocene epoch

    Science.gov (United States)

    Walter Anthony, K. M.; Zimov, S. A.; Grosse, G.; Jones, Miriam C.; Anthony, P.; Chapin, F. S.; Finlay, J. C.; Mack, M. C.; Davydov, S.; Frenzel, P.F.; Frolking, S.

    2014-01-01

    Thermokarst lakes formed across vast regions of Siberia and Alaska during the last deglaciation and are thought to be a net source of atmospheric methane and carbon dioxide during the Holocene epoch1,2,3,4. However, the same thermokarst lakes can also sequester carbon5, and it remains uncertain whether carbon uptake by thermokarst lakes can offset their greenhouse gas emissions. Here we use field observations of Siberian permafrost exposures, radiocarbon dating and spatial analyses to quantify Holocene carbon stocks and fluxes in lake sediments overlying thawed Pleistocene-aged permafrost. We find that carbon accumulation in deep thermokarst-lake sediments since the last deglaciation is about 1.6 times larger than the mass of Pleistocene-aged permafrost carbon released as greenhouse gases when the lakes first formed. Although methane and carbon dioxide emissions following thaw lead to immediate radiative warming, carbon uptake in peat-rich sediments occurs over millennial timescales. We assess thermokarst-lake carbon feedbacks to climate with an atmospheric perturbation model and find that thermokarst basins switched from a net radiative warming to a net cooling climate effect about 5,000 years ago. High rates of Holocene carbon accumulation in 20 lake sediments (47±10 grams of carbon per square metre per year; mean±standard error) were driven by thermokarst erosion and deposition of terrestrial organic matter, by nutrient release from thawing permafrost that stimulated lake productivity and by slow decomposition in cold, anoxic lake bottoms. When lakes eventually drained, permafrost formation rapidly sequestered sediment carbon. Our estimate of about 160petagrams of Holocene organic carbon in deep lake basins of Siberia and Alaska increases the circumpolar peat carbon pool estimate for permafrost regions by over 50 per cent (ref. 6). The carbon in perennially frozen drained lake sediments may become vulnerable to mineralization as permafrost disappears7

  7. Mangrove production and carbon sinks: a revision of global budget estimates

    NARCIS (Netherlands)

    Bouillon, S.; Borges, A.V.; Castañeda-Moya, E.; Diele, K.; Dittmar, T.; Duke, N.C.; Kristensen, E.; Lee, S.; Marchand, C.; Middelburg, J.J.; Rivera-Monroy, V.H.; Smith III, T.; Twilley, R.R.

    2008-01-01

    Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove pri

  8. Contribution of Oxygenic Photosynthesis to Palaeo-Oceanic Organic Carbon Sink Fluxes in Early Cambrian Upper Yangtze Shallow Sea:Evidence from Black Shale Record

    Institute of Scientific and Technical Information of China (English)

    Kunyu Wu; Tingshan Zhang; Yang Yang; Yuchuan Sun; Daoxian Yuan

    2016-01-01

    ABSTRACT:The extensive transgression that occurred on the Yangtze Plate in Early Cambrian led to a massive organic carbon pool in the Niutitang Formation. A black shale core section from 3 251.08 to 3 436.08 m beneath the Earth’s surface was studied to estimate the contribution of oxygenic photosyn-thesis to organic carbon sink fluxes in Early Cambrian Upper Yangtze shallow sea. Results indicate that the oxygenic photosynthesis played the most important role in carbon fixation in Early Cambrian. Or-ganic carbon sink was mainly contributed by photosynthetic microorganisms, e.g., cyanobacteria, algae and archaea. The Niutitang Formation was formed in a deep anoxic marine shelf sedimentary envi-ronment at a sedimentation rate of ~0.09±0.03 mm/yr. The initial TOC abundance in Niutitang shale ranged from 0.18%to 7.09%, with an average of 2.15%. In accordance with the sedimentation rate and initial TOC abundance, organic carbon sink fluxes were calculated and found to range from 0.21 to 8.10×103 kg/km2·yr-1, especially the organic carbon sink fluxes in depth between 3 385 and 3 470 m range from 3.80 to 8.10×103 kg/km2·yr-1, with an average of~6.03×103 kg/km2·yr-1, which is much high-er than that of contemporary marine sediments. The organic carbon sink fluxes of Niutitang shale are equal to 0.56 to 21.61×103 kg/km2·yr-1 net oxygen emitted into the Early Cambrian ocean and atmos-phere, this emitted oxygen may have significantly promoted the oxygen level of the Earth’s surface and diversification of metazoans.

  9. Red mud as a carbon sink: variability, affecting factors and environmental significance.

    Science.gov (United States)

    Si, Chunhua; Ma, Yingqun; Lin, Chuxia

    2013-01-15

    The capacity of red mud to sequester CO(2) varied markedly due to differences in bauxite type, processing and disposal methods. Calcium carbonates were the dominant mineral phases responsible for the carbon sequestration in the investigated red mud types. The carbon sequestration capacity of red mud was not fully exploited due to shortages of soluble divalent cations for formation of stable carbonate minerals. Titanate and silicate ions were the two major oxyanions that appeared to strongly compete with carbonate ions for the available soluble Ca. Supply of additional soluble Ca and Mg could be a viable pathway for maximizing carbon sequestration in red mud and simultaneously reducing the causticity of red mud. It is roughly estimated that over 100 million tonnes of CO(2) have been unintentionally sequestered in red mud around the world to date through the natural weathering of historically produced red mud. Based on the current production rate of red mud, it is likely that some 6 million tonnes of CO(2) will be sequestered annually through atmospheric carbonation. If appropriate technologies are in place for incorporating binding cations into red mud, approximately 6 million tonnes of additional CO(2) can be captured and stored in the red mud while the hazardousness of red mud is simultaneously reduced.

  10. Radiocarbon evidence for a smaller oceanic carbon dioxide sink than previously believed

    Energy Technology Data Exchange (ETDEWEB)

    Hesshaimer, Vago; Levin, Ingeborg (Heidelberg Univ. (Germany). Inst. fuer Umweltphysik); Heimann, Martin (Max-Planck-Institut fuer Meteorologie, Hamburg (Germany))

    1994-07-21

    Radiocarbon produced naturally in the upper atmosphere or artificially during nuclear weapons testing is the main tracer used to validate models of oceanic carbon cycling, in particular the exchange of carbon dioxide with the atmosphere and the mixing parameters within the ocean itself. Here we test the overall consistency of exchange fluxes between all relevant compartments in a simple model of the global carbon cycle, using measurements of the long-term tropospheric CO[sub 2] concentration and radiocarbon composition, the bomb [sup 14]C inventory in the stratosphere and a compilation of bomb detonation dates and strengths. (author).

  11. Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Zhou; Xiaoke Wang; Lei Tong; Hongxing Zhang; Fei Lu; Feixiang Zheng; Peiqiang Hou; Wenzhi Song; Zhiyun Ouyang

    2012-01-01

    The significant wanning in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations.However,it is less known of the climate feedback of urban lawn in warmed environment.Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing,China.The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was-0.71 μmol/(m2·sec),the ecosytem was a CO2 sink under soil warming treatment,the lawn ecosystem under the control was a CO2 source (0.13 μmol/(m2·sec)),indicating that the lawn ecosystem would provide a negative feedback to global warming.There was no significant effect of soil warming on nocturnal NEE (i.e.,ecosystem respiration),although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86,much lower than that in the control (7.03).The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and Amax (maximutn rate of photosynthesis).Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.

  12. Implications of albedo changes following afforestation on the benefits of forests as carbon sinks

    Science.gov (United States)

    Kirschbaum, M. U. F.; Whitehead, D.; Dean, S. M.; Beets, P. N.; Shepherd, J. D.; Ausseil, A.-G. E.

    2011-12-01

    Increased carbon storage with afforestation leads to a decrease in atmospheric carbon dioxide concentration and thus decreases radiative forcing and cools the Earth. However, afforestation also changes the reflective properties of the surface vegetation from more reflective pasture to relatively less reflective forest cover. This increase in radiation absorption by the forest constitutes an increase in radiative forcing, with a warming effect. The net effect of decreased albedo and carbon storage on radiative forcing depends on the relative magnitude of these two opposing processes. We used data from an intensively studied site in New Zealand's Central North Island that has long-term, ground-based measurements of albedo over the full short-wave spectrum from a developing Pinus radiata forest. Data from this site were supplemented with satellite-derived albedo estimates from New Zealand pastures. The albedo of a well-established forest was measured as 13 % and pasture albedo as 20 %. We used these data to calculate the direct radiative forcing effect of changing albedo as the forest grew. We calculated the radiative forcing resulting from the removal of carbon from the atmosphere as a decrease in radiative forcing of -104 GJ tC-1 yr-1. We also showed that the observed change in albedo constituted a direct radiative forcing of 2759 GJ ha-1 yr-1. Thus, following afforestation, 26.5 tC ha-1 needs to be stored in a growing forest to balance the increase in radiative forcing resulting from the observed albedo change. Measurements of tree biomass and albedo were used to estimate the net change in radiative forcing as the newly planted forest grew. Albedo and carbon-storage effects were of similar magnitude for the first four to five years after tree planting, but as the stand grew older, the carbon storage effect increasingly dominated. Averaged over the whole length of the rotation, the changes in albedo negated the benefits from increased carbon storage by 17-24 %.

  13. Eroding forest carbon sinks following thinning for combined fire prevention and bioenergy production

    Science.gov (United States)

    Hudiburg, T. W.; Law, B. E.; Luyssaert, S.

    2010-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. Using Forest Inventory Analysis (FIA) plot data, regional supplemental plot data, and remote sensing products we determined the carbon stocks and fluxes of West Coast forests under current and proposed management scenarios for a 20 year treatment period. Varying biofuels thinning treatments designed to meet multiple objectives emphasizing fire prevention, economic gain, or energy production were applied to determine the resulting net carbon balance and bioenergy potential. Contrary to the management objectives, we find that increased removals result in substantial decreases in forest carbon stocks and Net Biome Production (NBP) and increased emissions. Thinning forests for energy production is not carbon neutral. Emissions are estimated to increase over the 20-year period because preventive thinning removals exceed the CO2 that would have been emitted due to wildfires, fossil fuel inputs are required for harvest and manufacturing, and use of woody biomass in short-lived products emits large quantities of CO2 to the atmosphere. It has the net effect of releasing otherwise sequestered carbon to the atmosphere, which may effectively reduce ongoing carbon uptake by forests and as a result, increase net greenhouse gas emissions, undermining the objective of greenhouse gas reductions over the next several decades.

  14. Issues and potential in creating carbon sinks in the boreal forest; Potentiel et enjeux a propos de la creation de puits de carbone en foret boreale

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, J.F.; Gagnon, R.; Villeneuve, C. [Quebec Univ., Chicoutimi, PQ (Canada); Gaboury, S. [Rio Tinto Alcan, Montreal, PQ (Canada); Lord, D. [Quebec Univ., Chicoutimi, PQ (Canada). Dept. des Sciences Fondamentales

    2008-09-15

    Although greenhouse gas (GHG) emissions are primarily associated with the combustion of fossil fuels, they are also linked to deforestation. This article discussed the contribution of the forestry sector in mitigating climate change in the province of Quebec, which has vast areas of barren deforested land. Recent studies have shown that boreal forests have significant potential for carbon sequestration, although much uncertainty remains regarding the ability to store carbon for the long-term due to the potential for fires. Concerns regarding climate change may provide opportunities to develop important synergies between the wood products industry and bioenergy developers. This article presented a typical case of afforestation of barren boreal lands and noted the benefits of reforestation in terms of creating new habitats for species. This article also included a chart indicating the carbon sequestration potential for different types of biomass, notably tree canopies, roots, forest litter, deadwood and soil. A map showing the spatial distribution of bare boreal regions in Quebec was also included along with the total cost per hectare of carbon sequestration per tonne of carbon dioxide. It was concluded that important reforestation projects can be undertaken in the context of mitigating climate change to restore the role of carbon sinks which were lost in the unproductive barren regions. 45 refs., 2 tabs., 3 figs.

  15. ENHANCEMENT OF TERRESTRIAL CARBON SINKS THROUGH RECLAMATION OF ABANDONED MINE LANDS IN THE APPALACHIAN REGION

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Kronrad

    2002-12-01

    The U.S.D.I. Office of Surface Mining (OSM) estimates that there are approximately 1 million acres of abandoned mine land (AML) in the Appalachian region. AML lands are classified as areas that were inadequately reclaimed or were left unreclaimed prior to the passage of the 1977 Surface Mining Control and Reclamation Act, and where no federal or state laws require any further reclamation responsibility to any company or individual. Reclamation and afforestation of these sites have the potential to provide landowners with cyclical timber revenues, generate environmental benefits to surrounding communities, and sequester carbon in the terrestrial ecosystem. Through a memorandum of understanding, the OSM and the U.S. Department of Energy (DOE) have decided to investigate reclaiming and afforesting these lands for the purpose of mitigating the negative effects of anthropogenic carbon dioxide in the atmosphere. This study determined the carbon sequestration potential of northern red oak (Quercus rubra L.), one of the major reclamation as well as commercial species, planted on West Virginia AML sites. Analyses were conducted to (1) calculate the total number of tons that can be stored, (2) determine the cost per ton to store carbon, and (3) calculate the profitability of managing these forests for timber production alone and for timber production and carbon storage together. The Forest Management Optimizer (FORMOP) was used to simulate growth data on diameter, height, and volume for northern red oak. Variables used in this study included site indices ranging from 40 to 80 (base age 50), thinning frequencies of 0, 1, and 2, thinning percentages of 20, 25, 30, 35, and 40, and a maximum rotation length of 100 years. Real alternative rates of return (ARR) ranging from 0.5% to 12.5% were chosen for the economic analyses. A total of 769,248 thinning and harvesting combinations, net present worths, and soil expectation values were calculated in this study. Results indicate that

  16. Dynamics of carbon dioxide transport in a multiple sink network (GHGT-11)

    NARCIS (Netherlands)

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

    2013-01-01

    As Carbon Capture and Storage slowly gets accepted and integrated as a mean for cleaner utilization of fossil fuels, the integration of capture, transport and storage becomes a key component to properly design a CO2 network. While the boundary conditions set by the capture and storage units have bee

  17. Are soils of Iowa USA currently a carbon sink or source? Simulated changes in SOC stock from 1972 to 2007

    Science.gov (United States)

    Liu, S.; Tan, Z.; Li, Z.; Zhao, S.; Yuan, W.

    2011-01-01

    Upscaling the spatial and temporal changes in carbon (C) stocks and fluxes from sites to regions is a critical and challenging step toward improving our understanding of the dynamics of C sources and sinks over large areas. This study simulated soil organic C (SOC) dynamics within 0-100cm depth of soils across the state of Iowa in the USA from 1972 to 2007 using the General Ensemble biogeochemical Modeling System (GEMS). The model outputs with variation coefficient were analyzed and assembled from simulation unit to the state scale based upon major land use types at annual step. Results from this study indicate that soils (within a depth of 0-100cm) in Iowa had been a SOC source at a rate of 190??380kg Cha-1yr-1. This was likely caused by the installation of a massive drainage system which led to the release of SOC from deep soil layers previously protected under poor drainage conditions. The annual crop rotation was another major force driving SOC variation and resulted in spatial variability of annual budgets in all croplands. Annual rate of change of SOC stocks in all land types depended significantly on the baseline SOC levels; soils with higher SOC levels tended to be C sources, and those with lower levels tended to be C sinks. Management practices (e.g., conservation tillage and residue management practices) slowed down the C emissions from Iowa soils, but could not reverse the general trend of net SOC loss in view of the entire state due mainly to a high level of baseline SOC stocks. ?? 2010 Elsevier B.V.

  18. Implications of albedo changes following afforestation on the benefits of forests as carbon sinks

    Directory of Open Access Journals (Sweden)

    M. U. F. Kirschbaum

    2011-08-01

    Full Text Available Increased carbon storage with afforestation leads to a decrease in atmospheric carbon dioxide concentration and thus decreases radiative forcing and cools the Earth. However, land-use change also changes the reflective properties of the surface vegetation from more reflective pasture to relatively less reflective forest cover. This increase in radiation absorption by the forest constitutes an increase in radiative forcing, with a warming effect. The net effect of decreased albedo and carbon storage on radiative forcing depends on the relative magnitude of these two opposing processes.

    We used data from an intensively studied site in New Zealand's Central North Island that has long-term, ground-based measurements of albedo over the full short-wave spectrum from a developing Pinus radiata forest. Data from this site were supplemented with satellite-derived albedo estimates from New Zealand pastures. The albedo of a well-established forest was measured as 13 % and pasture albedo as 20 %. We used these data to calculate the direct radiative forcing effect of changing albedo as the forest grew.

    We calculated the radiative forcing resulting from the removal of carbon from the atmosphere as a decrease in radiative forcing of −104 GJ tC−1 yr−1. We also showed that the observed change in albedo constituted a direct radiative forcing of 2759 GJ ha−1 yr−1. Thus, following afforestation, 26.5 tC ha−1 needs to be stored in a growing forest to balance the increase in radiative forcing resulting from the observed albedo change. Measurements of tree biomass and albedo were used to estimate the net change in radiative forcing as the newly planted forest grew. Albedo and carbon-storage effects were of similar magnitude for the first four to five years after tree planting, but as the stand grew older, the carbon storage effect increasingly dominated. Averaged over the whole

  19. Implications of albedo changes following afforestation on the benefits of forests as carbon sinks

    Directory of Open Access Journals (Sweden)

    M. U. F. Kirschbaum

    2011-12-01

    Full Text Available Increased carbon storage with afforestation leads to a decrease in atmospheric carbon dioxide concentration and thus decreases radiative forcing and cools the Earth. However, afforestation also changes the reflective properties of the surface vegetation from more reflective pasture to relatively less reflective forest cover. This increase in radiation absorption by the forest constitutes an increase in radiative forcing, with a warming effect. The net effect of decreased albedo and carbon storage on radiative forcing depends on the relative magnitude of these two opposing processes.

    We used data from an intensively studied site in New Zealand's Central North Island that has long-term, ground-based measurements of albedo over the full short-wave spectrum from a developing Pinus radiata forest. Data from this site were supplemented with satellite-derived albedo estimates from New Zealand pastures. The albedo of a well-established forest was measured as 13 % and pasture albedo as 20 %. We used these data to calculate the direct radiative forcing effect of changing albedo as the forest grew.

    We calculated the radiative forcing resulting from the removal of carbon from the atmosphere as a decrease in radiative forcing of −104 GJ tC−1 yr−1. We also showed that the observed change in albedo constituted a direct radiative forcing of 2759 GJ ha−1 yr−1. Thus, following afforestation, 26.5 tC ha−1 needs to be stored in a growing forest to balance the increase in radiative forcing resulting from the observed albedo change. Measurements of tree biomass and albedo were used to estimate the net change in radiative forcing as the newly planted forest grew. Albedo and carbon-storage effects were of similar magnitude for the first four to five years after tree planting, but as the stand grew older, the carbon storage effect increasingly dominated. Averaged over the whole

  20. Harvested wood products and carbon sink in a young beech high forest

    OpenAIRE

    Pilli R; Dalla Valle E; Anfodillo T; Fontanella F; Penzo D

    2008-01-01

    According to art. 3.4 of the Kyoto Protocol (KP), Italy has elected forest management as additional human-induced activity to attain the goal of reduction in greenhouse gas emissions. The whole forest area not subjected to afforestation, reforestation or deforestation processes since 1990 will be considered as managed forest. In order to analyse different management strategies, the Carbon-Pro Project, involving 9 partners of the European CADSES area, considered a young beech high forest (ex-c...

  1. Impact of sinking carbon flux on accumulation of deep-ocean carbon in the Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; Saino, T.

    The export of carbon through the biological pump from the surface to the deep ocean has a direct influence on the removal of CO sub(2) from the atmosphere. This is because the carbon is sequestered for only a few days to months in the surface while...

  2. The Arctic CH4 sink and its implications for the permafrost carbon feedbacks to the global climate system

    Science.gov (United States)

    Juncher Jørgensen, Christian; Christiansen, Jesper; Mariager, Tue; Hugelius, Gustaf

    2016-04-01

    Using atmospheric methane (CH4), certain soil microbes are able to sustain their metabolism, and in turn remove this powerful greenhouse gas from the atmosphere. While the process of CH4 oxidation is a common feature in most natural and unmanaged ecosystems in temperate and boreal ecosystems, the interactions between soil physical properties and abiotic process drivers, net landscape exchange and spatial patterns across Arctic drylands remains highly uncertain. Recent works show consistent CH4 comsumption in upland dry tundra soils in Arctic and High Arctic environments (Christiansen et al., 2014, Biogeochemistry 122; Jørgensen et al., 2015, Nature Geoscience 8; Lau et al., 2015, The ISME Journal 9). In these dominantly dry or barren soil ecosystems, CH4 consumption has been observed to significantly exceed the amounts of CH4 emitted from adjacent wetlands. These observations point to a potentially important but largely overlooked component of the global soil-climate system interaction and a counterperspective to the conceptual understanding of the Arctic being a only a source of CH4. However, due to our limited knowledge of spatiotemporal occurrence of CH4 consumption across a wider range of the Arctic landscape we are left with substantial uncertainites and an overall unconstrained range estimate of this terrestrial CH4 sink and its potential effects on permafrost carbon feedback to the atmospheric CH4 concentration. To address this important knowledge gap and identify the most relevant spatial scaling parameters, we studied in situ CH4 net exchange across a large landscape transect on West Greenland. The transect representated soils formed from the dominant geological parent materials of dry upland tundra soils found in the ice-free land areas of Western Greenland, i.e. 1) granitic/gneissic parent material, 2) basaltic parent material and 3) sedimentary deposits. Results show that the dynamic variations in soil physical properties and soil hydrology exerts an

  3. Review on worldwide study of ocean biological carbon sink%国际海洋生物碳汇研究进展

    Institute of Scientific and Technical Information of China (English)

    刘慧; 唐启升

    2011-01-01

    Ocean is the biggest carbon sink in the world. The total carbon load of the ocean is 39× 1012t, which is 93% of total global carbon load, and about 53 times of carbon load of the atmosphere. Carbon in the ocean will either join in the biogeochemical cycle again, or be preserved for long periods; while some of the carbon will be stored in the seabed forever. According to the Blue Carbon report by UN, about 55% global biological carbon or green carbon capture is accomplished by marine organisms. These marine organisms include phytoplankton, bacteria, seaweeds, salt marshes and mangroves. Marine plants or flora have high capacity and efficiency for carbon sequestration. The findings on marine biological carbon sink by worldwide studies are reviewed in this paper.Major mechanisms governing the marine biological carbon sink are described, along with its present status and approaches for its restoration. Additionally, the function of seaweed and bivalves mariculture as components of fisheries carbon sink is evaluated.%海洋是地球上最大的碳库.整个海洋中蓄积的碳总量达到39×1012t,占全球碳总量的93%,约为大气的53倍.这些碳或重新进入生物地球化学循环,或被长期储存起来;而其中一部分被永久地储存在海底.根据联合国报告,地球上超过一半(55%)的生物碳或是绿色碳捕获是由海洋生物完成的,这些海洋生物包括浮游生物、细菌、海藻、盐沼植物和红树林.本文综述了近年国际上对海洋生物碳汇的研究结果,阐述了海洋生物固碳的机制、海洋生物碳汇的现状及其修复措施,同时评价和论述了海水贝藻养殖作为渔业碳汇的地位与作用.

  4. Water balance and carbon sink strength of an European savannah-type woodland during the drought year 2012

    Science.gov (United States)

    Piayda, A.; Dubbert, M.; Rebmann, C.; Kolle, O.; Costa e Silva, F.; Correia, A.; Pereira, J. S.; Werner, C.; Cuntz, M.

    2013-12-01

    Vc,max. The bulk reduction takes place in summer whereas only little reduction occurs during the spring drought anomaly. Understorey GPP was reduced by 87% and was affected rather instantaneously already in winter. Overall is the ecosystem a carbon sink in both years but with a reduced sink strength by 34% in the drought year 2012. In summary, the savannah-type ecosystem was strongly affected by the drought in 2012. Water availability was reduced due to a strong decrease in precipitation with little effect on evapotranspiration and canopy conductance. The carbon sink strength was strongly diminished by an early die-back of the understory vegetation and a reduced maximum carboxylation rate of the Q. suber trees.

  5. Managing carbon sinks in rubber (Hevea brasilensis plantation by changing rotation length in SW China.

    Directory of Open Access Journals (Sweden)

    Syed Moazzam Nizami

    Full Text Available Extension of the rotation length in forest management has been highlighted in Article 3.4 of the Kyoto Protocol to help the countries in their commitments for reduction in greenhouse gas emissions. CO2FIX Model Ver.3.2 was used to examine the dynamics of carbon stocks (C stocks in a rubber plantation in South Western China with the changing rotation lengths. To estimate the efficiency of increasing the rotation length as an Article 3.4 activity, study predicted that the rubber production and C stocks of the ecosystem increased with the increasing rotation (25, 30, 35, 40 and 45 years. While comparing the pace of growth both in economical (rubber production and ecological (C stocks terms in each rotation, 40 years rotation length showed maximum production and C stocks. After elongation of 40 year rotation to four consecutive cycles, it was concluded that the total C stocks of the ecosystem were 186.65 Mg ha(-1. The longer rotation lengths showed comparatively increased C stocks in below ground C stock after consecutive four rotations. The pace of C input (Mg C ha(-1 yr(-1 and rubber production indicated that 40 years rotation is best suited for rubber plantation. The study has developed carbon mitigation based on four rotation scenarios. The possible stimulated increase in C stocks of the entire ecosystem after consecutive long rotations indicated that the emphasis must be paid on deciding the rotation of rubber plantation in SW China for reporting under article 3.4 of the Kyoto Protocol.

  6. Elevated CO[sub 2] and altered source/sink relationships: Carbon allocation and nitrogen resorption in two annual grasses

    Energy Technology Data Exchange (ETDEWEB)

    Geeske, J.; Field, C.B.; Jackson, R.B. (Stanford Univ., CA (United States))

    1994-06-01

    Predicting plant response to elevated CO[sub 2] requires a better understanding of carbon and nitrogen interactions within plants. We altered C sources and sinks by increasing available CO[sub 2] and clipping tillers of two common annual species. (Avena fatua and Bromus mollis) and examined treatment effects on biomass, allocation, leaf and root properties, nitrogen pools and N retranslocation. Within 12 days of germination, total Avena biomass in elevated CO[sub 2] increased by 25%, but the increased biomass was exclusively in roots. After 7 weeks there was still no change in Avena shoot biomass in elevated CO[sub 2] and the number of tillers produced also was unchanged. Leaf mass per unit area increased 11 and 29% for Avena and Bromus grown in higher CO[sub 2]. Removing tillers increased the area of individual Avena leaves by 60% and resulted in significantly thinner roots, independent of CO[sub 2] treatment. We summarize biomass, allocation, and N resorption for each species from germination through flowering.

  7. Fine root branch orders respond differentially to carbon source-sink manipulations in a longleaf pine forest.

    Science.gov (United States)

    Guo, Dali L; Mitchell, Robert J; Hendricks, Joseph J

    2004-08-01

    Fine roots are a key component of carbon (C) flow and nitrogen (N) cycling in forest ecosystems. However, the complexity and heterogeneity of the fine root branching system have hampered the assessment and prediction of C and N dynamics at ecosystem scales. We examined how root morphology, biomass, and chemistry differed with root branch orders (1-5 with root tips classified as first order roots) and how different root orders responded to increased C sink strength (via N fertilization) and reduced carbon source strength (via canopy scorching) in a longleaf pine (Pinus palustris L.) ecosystem. With increasing root order, the diameter and length of individual roots increased, whereas the specific root length decreased. Total root biomass on an areal basis was similar among the first four orders but increased for the fifth order roots. Consequently, total root length and total root surface area decreased systematically with increasing root order. Fine root N and lignin concentrations decreased, while total non-structural carbohydrate (TNC) and cellulose concentrations increased with increasing root order. N addition and canopy disturbance did not alter root morphology, but they did influence root chemistry. N fertilization increased fine root N concentration and content per unit area in all five orders, while canopy scorching decreased root N concentration. Moreover, TNC concentration and content in fifth order roots were also reduced by canopy scorching. Our results indicate that the small, fragile, and more easily overlooked first and second order roots may be disproportionately important in ecosystem scale C and N fluxes due to their large proportions of fine root biomass, high N concentrations, relatively short lifespans, and potentially high decomposition rates.

  8. Jellyfish blooms result in a major microbial respiratory sink of carbon in marine systems.

    Science.gov (United States)

    Condon, Robert H; Steinberg, Deborah K; del Giorgio, Paul A; Bouvier, Thierry C; Bronk, Deborah A; Graham, William M; Ducklow, Hugh W

    2011-06-21

    Jellyfish blooms occur in many estuarine and coastal regions and may be increasing in their magnitude and extent worldwide. Voracious jellyfish predation impacts food webs by converting large quantities of carbon (C), fixed by primary producers and consumed by secondary producers, into gelatinous biomass, which restricts C transfer to higher trophic levels because jellyfish are not readily consumed by other predators. In addition, jellyfish release colloidal and dissolved organic matter (jelly-DOM), and could further influence the functioning of coastal systems by altering microbial nutrient and DOM pathways, yet the links between jellyfish and bacterioplankton metabolism and community structure are unknown. Here we report that jellyfish released substantial quantities of extremely labile C-rich DOM, relative to nitrogen (25.6 ± 31.6 C:1N), which was quickly metabolized by bacterioplankton at uptake rates two to six times that of bulk DOM pools. When jelly-DOM was consumed it was shunted toward bacterial respiration rather than production, significantly reducing bacterial growth efficiencies by 10% to 15%. Jelly-DOM also favored the rapid growth and dominance of specific bacterial phylogenetic groups (primarily γ-proteobacteria) that were rare in ambient waters, implying that jelly-DOM was channeled through a small component of the in situ microbial assemblage and thus induced large changes in community composition. Our findings suggest major shifts in microbial structure and function associated with jellyfish blooms, and a large detour of C toward bacterial CO(2) production and away from higher trophic levels. These results further suggest fundamental transformations in the biogeochemical functioning and biological structure of food webs associated with jellyfish blooms.

  9. Sources and sinks of carbonyl sulfide in a mountain grassland and relationships to the carbon dioxide exchange

    Science.gov (United States)

    Spielmann, Felix M.; Kitz, Florian; Hammerle, Albin; Gerdel, Katharina; Wohlfahrt, Georg

    2016-04-01

    The trace gas carbonyl sulfide (COS) has been proposed as a tracer for canopy gross primary production (GPP), canopy transpiration and stomatal conductance of plant canopies in the last few years. COS enters the plant leaf through the stomata and diffuses through the intercellular space, the cell wall, the plasma membrane and the cytosol like CO2. It is then catalyzed by the enzyme carbonic anhydrase (CA) in a one-way reaction to H2S and CO2. This one-way flux into the leaf makes COS a promising tracer for the GPP. However there is growing evidence, that plant leaves aren't the only contributors to the ecosystem flux of COS. Therefor the COS uptake of soil microorganisms also containing CA and abiotic COS production might have to be accounted for when using COS as a tracer at the ecosystem scale. The overarching objective of this study was to quantify the relationship between the ecosystem-scale exchange of COS, CO2 and H2O and thus to test for the potential of COS to be used as a tracer for the plant canopy CO2 and H2O exchange. More specifically we aimed at quantifying the contribution of the soil to the ecosystem-scale COS exchange in order to understand complications that may arise due to a non-negligible soil COS exchange. In May 2015 we set up our quantum cascade laser (QCL) (Aerodyne Research Inc., MA, USA) at a temperate mountain grassland in Stubai Valley close to the village of Neustift, Austria. Our site lies at the valley bottom and is an intensively managed mountain grassland, which is cut 3-4 times a year. With the QCL we were able to measure concurrently the concentrations of COS, CO2, H2O (and CO) at a frequency of 10 Hz with minimal noise. This allowed us to conduct ecosystem-scale eddy covariance measurements. The eddy covariance flux measurements revealed that the COS uptake continues at night, which we confirmed was not caused by soil microorganisms, as the soil exchange was close to neutral during nighttime. Instead, the nocturnal COS uptake

  10. The dynamic of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth: implications for modelling

    Science.gov (United States)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-02-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will condition the response of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study is to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). Combining field measurements and process-based simulations at 49 sites (931 site-years), we assessed the stand biomass growth dependences at both inter-site and inter-annual scales. Specifically, the relative influence of forest C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in stand C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual stand woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. We provide an evaluation of the spatio-temporal dynamics of annual carbon allocation to wood in European forests. Our study supports the premise that European forest growth is under a complex control including both source and sink limitations. The relative influences of the different growth drivers strongly vary across years and spatial ecological gradients. We suggest a

  11. 典型岩溶水系统碳汇通量估算%Flux Estimation of Carbon Sink in Typical Karst Water Systems

    Institute of Scientific and Technical Information of China (English)

    裴建国; 章程; 张强; 朱琴

    2012-01-01

    现代岩溶学研究成果表明,碳酸盐岩在全球碳循环中响应极其迅速,水循环过程中的碳汇效应显著.本研究选取广西桂林寨底地下河系统、广西环江大安地下河系统、重庆北碚青木关地下河系统三个典型岩溶地下水系统,利用各系统地下河的流量和HCO3-浓度的监测资料,采用简单化学平衡模式法估算碳汇通量(CO2).结果显示,寨底地下河系统的单位面积年碳汇通量为68.82 t/( km2.a),大安地下河系统的单位面积年碳汇通量为81.18 t/(km2.a),青木关地下河系统的单位面积年碳汇通量为100.07 t/(km2.a).分析认为同一个岩溶水系统的结构特征和环境条件基本上是稳定的;地下河的流量和HCO3-浓度是影响岩溶碳汇强度的关键因素,尤其是地下河流量的变化对碳汇强度的影响显著;不同岩溶水系统的碳汇通量不但受水化学条件和地下水动力条件的控制,同时受土地利用变化的影响.该研究对于改进碳循环模型和评价岩溶地质碳汇有重要意义.%Select results from modern karstology research show that carbonate rock can be actively involved in the global carbon cycle with a quick response, thus the carbon sink effect from the water cycle in carbonate rock areas is very important. As described in this paper, three representative karst groundwater systems were selected, including Guangxi province Guilin Zhaidi, Guangxi province Huanjiang county Da'an groundwater and Chongqing Qingmuguan groundwater. Carbon sink flux ( CO2 ) of each underground water system was estimated from the serial monitoring data of discharges and bicarbonate concentrations by using the simple chemical equilibrium method. The fluxes in Zhaidi, Da'an and Qingmuguan were 68. 82 t/(km2 ?a) , 81. 18 t/(km2 ?a) and 100. 07 t/(km2 ?a) respectively. The structures and environmental conditions in each karst water system were relatively stable; accordingly, the groundwater discharge and HC03

  12. Re-establishing marshes can return carbon sink functions to a current carbon source in the Sacramento-San Joaquin Delta of California, USA

    Science.gov (United States)

    Miller, Robin L.; Fujii, Roger; Schmidt, Paul E.

    2011-01-01

    . Decomposition rates were related to differences in hydrologic conditions, including water temperature, pH, dissolved oxygen concentration, and availability of alternate electron acceptors. The study showed that marsh re-establishment with permanent, low energy, shallow flooding can limit oxidation of organic soils, thus, effectively turning subsiding land from atmospheric carbon sources to carbon sinks, and at the same time reducing flood vulnerability.

  13. Characteristics of carbon cycles and mechanism of carbon sink in inland fishery ecosystem%内陆渔业生态系统的碳循环特征及碳汇机制

    Institute of Scientific and Technical Information of China (English)

    杨健; 苏彦平; 刘洪波; 戈贤平

    2012-01-01

    Inland fishery carbon sink (IFCS)refers to the process and mechanism in which fishery organisms absorb and sequestrate CO2 sequestrate CO2 in the water and remove it from the water, and consequently, inland carbon sink fishery (ICSF) will be any fishery activity that effectively promotes a relative increase of IFCS. Phytoplankton fixes CO2 through photosynthesis and converts it into organic carbon. Quite much of it is taken up by major freshwater herbivorous and filter-feeding fish and mussels, and accordingly, carbon can be cascaded through aquatic food webs and removed by capture fisheries and aqua-culture. Therefore, ICSF can not only provide large quantities of nutritious food, but also play a critical role in carbon sequestration and removal. Carbon in freshwater ecosystems can be made up of different chemical components, like particulate organic and inorganic carbon, dissolved inorganic and organic carbon, which are convertible with high dynamics. It is noteworthy that unsustainable fishing related activities will jeopardize the potential capacities and even ecosystem services of IFCS. Therefore, the importance of IFCS and ICSF must be highlighted. A more recent study suggested that aquaculture ponds (110 830 km2) sequester an estimated 16.6 million tonnes/year of carbon globally, and the most carbon sequestration occurs in Asia and particularly in China (94% and 55.9% of global aquaculture pond area, respectively). Fishery will be the only controllable industry that is possible to effectively increase the carbon sink capacity in aquatic ecosystem, and the carbon sink fishery will be the only carbon sink industry in aquatic ecosystem. To better understand the mechanism of carbon sink/source, the current focus of study should be on the natural laws of carbon cycles in inland fishery ecosystem (including natural waters and ponds), form conversion between different chemical components, the carbon footprint for each of the different inland fisheries and

  14. Toward restoring the net carbon sink function of degraded peatlands: Short-term response in CO2 exchange to ecosystem-scale restoration

    Science.gov (United States)

    Waddington, J. M.; Strack, M.; Greenwood, M. J.

    2010-03-01

    Northern peatlands represent a globally important stock of soil carbon and have acted as a net sink of atmospheric CO2 throughout the Holocene. Disturbance for horticultural peat extraction disrupts ecosystem function and converts these ecosystems to large, persistent sources of carbon dioxide (CO2). This study investigates the effect of ecosystem-scale restoration on growing season CO2 exchange in a peatland by comparing a restored site to a neighboring nonrestored section for 1 year prerestoration (1999) and 3 years postrestoration (2000-2002). Prior to restoration, less than 23% of the site was vegetated, and it was a source of 245 g C m-2 to the atmosphere during the growing season (May to early October). Following restoration, the water table remained deep, and soil moisture was significantly higher than the nonrestored section. By the third year postrestoration, vegetation covered 50% of the restored peatland. Moss covered 90% of this vegetated area. Vegetation productivity at the restored site was also enhanced with gross ecosystem photosynthesis under full light conditions significantly higher at the restored site at both moss and herbaceous plots by 2002. While this increase in vegetation productivity provided fresh substrate and resulted in higher CO2 production potential for restored site peat, ecosystem respiration was similar to or lower than that at the nonrestored site for both bare peat and vegetated areas because of the generally wetter site conditions resulting from restoration. By upscaling chamber CO2 exchange measurements to the ecosystem level, on the basis of the relative proportion of each surface cover type, we determined the site was a net sink of ˜20 ± 5 g C m-2 during the growing season only 2 years postrestoration. Combining our results with previous work on CH4 emissions and dissolved organic carbon export, we suggest that this degraded peatland ecosystem will likely return to a net carbon sink in 6 to 10 years postrestoration.

  15. A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches

    NARCIS (Netherlands)

    Jiang, Fei; Chen, Jing M.; Zhou, Lingxi; Ju, Weimin; Zhang, Huifang; Machida, Toshinobu; Ciais, Philippe; Peters, Wouter; Wang, Hengmao; Chen, Baozhang; Liu, Lixin; Zhang, Chunhua; Matsueda, Hidekazu; Sawa, Yousuke

    2016-01-01

    Atmospheric inversions use measurements of atmospheric CO2 gradients to constrain regional surface fluxes. Current inversions indicate a net terrestrial CO2 sink in China between 0.16 and 0.35 PgC/yr. The uncertainty of these estimates is as large as the mean because the atm

  16. A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches

    NARCIS (Netherlands)

    Jiang, Fei; Chen, Jing M; Zhou, Lingxi; Ju, Weimin; Zhang, Huifang; Machida, Toshinobu; Ciais, Philippe; Peters, Wouter; Wang, Hengmao; Chen, Baozhang; Liu, Lixin; Zhang, Chunhua; Matsueda, Hidekazu; Sawa, Yousuke

    2016-01-01

    Atmospheric inversions use measurements of atmospheric CO2 gradients to constrain regional surface fluxes. Current inversions indicate a net terrestrial CO2 sink in China between 0.16 and 0.35 PgC/yr. The uncertainty of these estimates is as large as the mean because the atmospheric network historic

  17. Erosion of soil organic carbon at high latitudes and its delivery to Arctic Ocean sediments: New source to sink insight from radiocarbon dating

    Science.gov (United States)

    Hilton, Robert; Galy, Valier; Gaillardet, Jerome; Dellinger, Mathieu; Bryant, Charlotte; O'Regan, Matt; Grocke, Darren; Coxall, Helen

    2016-04-01

    Soils of the northern high latitudes store carbon over thousands of years and contain almost double the carbon stock of the atmosphere. Erosion processes can mobilise this pre-aged soil organic carbon from the landscape and supply it to rivers. If it escapes degradation during river transport and is delivered to the coastal ocean, this carbon may be sequestered for much longer periods of time (>104 yr) as a geological CO2 sink. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers draining the high latitudes remains poorly constrained. Using radiocarbon activity, we quantify POC source, flux and fate in the Mackenzie River, the main sediment supplier to the Arctic Ocean. When combined with stable carbon isotopes and element ratios, the radiocarbon activity of POC allows us to distinguish inputs of POC from sedimentary rocks and quantify the average age of biospheric POC (from vegetation and soil) transported through the river system. We find that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5800±800 years. This is much older than large tropical rivers where we have equivalent data (Amazon River, Ganges River), and likely reflects the longer residence time of organic matter in cold, wet, high latitude soils. Based on the measured biospheric POC content and annual sediment flux, we calculate a biospheric POC flux of 2.2 (+1.3/-0.9) TgC yr-1 from the Mackenzie River. This is the largest input of aged organic carbon to the Arctic Ocean, more than the combined POC flux from the Eurasian Rivers. Offshore, we use a marine core to investigate organic carbon burial over the Holocene period. Radiocarbon measurements of bulk organic carbon reveal a significant offset from benthic foraminifera radiocarbon ages throughout the core, which is dependent upon the grain size of the sediments. Organic matter in sediments >63μm are offset from foraminifera by ˜ 6,000 14C years

  18. Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed

    Directory of Open Access Journals (Sweden)

    F. Márquez-García

    2013-05-01

    Full Text Available The olive tree is one of the most important crops in Spain, and the main one in the region of Andalusia. Most orchards are rain-fed, with high slopes where conventional tillage (CT is the primary soil management system used. These conditions lead to high erosion and a significant transport of organic carbon (OC. Moreover, soil tillage accelerates the oxidation of the OC. Cover crops (CC are the conservation agriculture (CA approach for woody crops. They are grown in-between tree rows to protect the soil against water erosion and their organic residues also help to increase the soil carbon (C sink. Soil and OC losses associated to the sediment were measured over four seasons (2003-07 using micro-plots for the collection of runoff and sediment in five experimental fields located in rain-fed olive orchards in Andalusia. Two soil management systems were followed, CC and CT. Furthermore, the changes in soil C in both systems were analyzed at a depth of 0-25 cm. CC reduced erosion by 80.5%, and also OC transport by 67.7%. In addition, Cover crops increased soil C sink by 12.3 Mg ha-1 year-1 of carbon dioxide (CO2 equivalent, with respect to CT. CC in rainfed olive orchards in a Mediterranean climate could be an environmental friendly and profitable system for reducing erosion and increasing the soil C sink. However, C fixing rate is not regular, being very high for the initial years after shifting from CT to CC and gradually decreasing over time.

  19. Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Garcia, F.; Gonzalez-Sanchez, E. J.; Castro-Garcia, S.; Ordonez-Fernandez, R.

    2013-06-01

    The olive tree is one of the most important crops in Spain, and the main one in the region of Andalusia. Most orchards are rain-fed, with high slopes where conventional tillage (CT) is the primary soil management system used. These conditions lead to high erosion and a significant transport of organic carbon (OC). Moreover, soil tillage accelerates the oxidation of the OC. Cover crops (CC) are the conservation agriculture (CA) approach for woody crops. They are grown in-between tree rows to protect the soil against water erosion and their organic residues also help to increase the soil carbon (C) sink. Soil and OC losses associated to the sediment were measured over four seasons (2003-07) using micro-plots for the collection of runoff and sediment in five experimental fields located in rain-fed olive orchards in Andalusia. Two soil management systems were followed, CC and CT. Furthermore, the changes in soil C in both systems were analyzed at a depth of 0-25 cm. CC reduced erosion by 80.5%, and also OC transport by 67.7%. In addition, CC increased soil C sink by 12.3 Mg ha{sup -}1 year{sup -}1 of carbon dioxide (CO{sub 2}) equivalent, with respect to CT. Cover crops in rainfed olive orchards in a Mediterranean climate could be an environmental friendly and profitable system for reducing erosion and increasing the soil C sink. However, C fixing rate is not regular, being very high for the initial years after shifting from CT to CC and gradually decreasing over time. (Author) 57 refs.

  20. Pengaruh Aerasi dan Sumber Nutrien terhadap Kemampuan Alga Filum Chlorophyta dalam Menyerap Karbon (Carbon Sink untuk Mengurangi Emisi CO2 di Kawasan Perkotaan

    Directory of Open Access Journals (Sweden)

    Lancur Setoaji

    2013-09-01

    Full Text Available Penelitian terkait mitigasi pemanasan global, khususnya dalam penyerapan karbon dioksida (CO2, menjadi fokus utama di kalangan ilmuwan dunia. Secara alamiah, karbon dioksida dapat diserap oleh tumbuhan hijau, laut, karbonasi batuan kapur, dan alga. Pigmen hijau dalam alga atau klorofil dapat menyerap karbon dioksida dalam proses fotosintesis. Alga memiliki pertumbuhan yang sangat cepat sehingga cocok digunakan sebagai carbon sink. Penelitian terkait carbon sink ini bertujuan untuk menentukan kemampuan rata-rata serapan CO2 oleh alga di kawasan perkotaan dan menentukan pengaruh aerasi dan variasi sumber N terhadap pertumbuhan dan perkembangan alga. Penelitian ini dilakukan dalam skala laboratorium menggunakan reaktor dengan proses batch. Sampel alga yang digunakan didapatkan dari hasil pengembangbiakan yang bersumber dari perairan di kawasan perkotaan. Penelitian ini menggunakan dua variabel uji, yaitu aerasi dan sumber nutrien. Jumlah karbon dioksida yang diserap didapatkan dari perbandingan stoikiometri pada reaksi fotosintesis.  Berdasarkan perbandingan stoikiometri tersebut diketahui bahwa 1 gram sel alga yang terbentuk sebanding dengan 1,92 gram CO2 yang diserap. Dari hasil penelitian, alga dengan penambahan pupuk urea dapat menyerap 4,87 mg CO2/hari dalam kondisi tanpa aerasi atau 3,84 mg CO2/hari dengan aerasi. Sedangkan alga dengan penambahan pupuk NPK dapat menyerap 3,61 mg CO2/hari dalam kondisi tanpa aerasi atau 3,01 mg CO2/hari dengan aerasi.

  1. Examining early-diagenetic processes as a chief sink for carbonate in the aftermath of the Triassic-Jurassic crisis: Hettangian concretions of Muller Canyon, NV, USA

    Science.gov (United States)

    Ritterbush, K. A.; Loyd, S. J.; Corsetti, F. A.; Bottjer, D. J.; Berelson, W.

    2015-12-01

    Tectonic, climate, and biotic changes across the Triassic-Jurassic transition appear to have resulted in a "carbonate gap" in the rock record of many shallow marine environments. Ecological state changes documented in near-shore settings in both Tethys and Panthassa show an earliest Jurassic switch to sponge-dominated biosiliceous sedimentation regimes. The Sunrise Formation exposed in the Gabbs Valley Range of Nevada (USA) records a peculiar juxtaposition of Hettangian carbonate-rich strata that contain demosponge spicules as the primary bioclast. It is unclear 1) why biocalcifiers were not recorded in higher abundance in this near-shore back-arc basin setting; 2) why carbonates formed following a biosiliceous regime; and 3) what the lithology indicates about post-extinction marine geochemical dynamics. Detailed sedimentological, paleontological, and geochemical analyses were applied to a 20-m thick sequence of limestone and chert in the Muller Canyon area, which is the Auxiliary Stratotype for the Triassic/Jurassic boundary. Concretion anatomy, bioclast microfacies, and oxygen and carbon isotopic signatures all indicate the Hettangian limestones are chiefly diagenetic concretions that all formed very shallowly, some essentially at the sediment-water interface. We infer that local bottom waters and/or pore waters were supersaturated with respect to calcium carbonate and that this contributed to widespread concretion sedimentation independent of biomineralization. Ecological incumbency of the demosponge meadows may have been supported by concurrent augmentation of marine silica concentration and this apparently proved inhospitable to re-colonization of benthic biocalcifying macrofauna. Together the biotic and lithologic consequences of the extinction represent million-year scale ecological restructuring and highlight early diagenetic precipitation as a major sink in long-term regional carbonate cycling. Perhaps the widespread 'carbonate gap' is actually a gap in

  2. 广东省能源消费碳排放与森林碳汇的研究%Research on the Carbon Emission and Forest Carbon Sink in Energy Consumption of Guangdong Province

    Institute of Scientific and Technical Information of China (English)

    石洪艾; 严敏悦

    2015-01-01

    以广东省为研究对象 ,选取1992~2012年时间区间 ,利用枟IPCC 2006国家温室气体清单指南枠中的碳排放计算公式和能源排放系数缺省值 ,从碳源和碳汇两个源头分析了广东省的碳排放强度.结果表明 :广东省以煤炭和石油为主的能源消费结构有所改善 ,碳强度逐年下降 ,能源利用率有所提高.1992~2012年间 ,广东省的碳排放量随着广东省GDP增长而增加 ,年均增长率为7% ;森林碳汇量逐年增加 ,年均增长率为4% ,森林碳汇的增加得益于森林蓄积量 ,而非森林面积 ,广东省仍存在较大的碳汇缺口.%Taking the Guangdong province as study object ,We select the article selects the time interval from 1992-to 2012 years of Guangdong Province and uses of the computational formulas of carbon emission and coefficients defaults of energy emissions in "IPCC2006 National Greenhouse Gas Inventories" to analyzes the carbon emissions intensity of Guangdong province from the aspects of carbon sources and sinks.The results indicate that the coal and oil-based energy consumption structure of Guangdong has improved ,and the carbon intensity declines while the , energy utilization rate has improved.Between 1992 and 2012 ,the carbon emissions of Guangdong increased at an average annual growth rate of 7% with the GDP growth;forest carbon sink increased every year with an average annual growth rate of 4%.The increases of forest carbon sink benefits from the forest stock volume rather than the forest area.However ,there are still large gaps in carbon sinks of Guangdong province.

  3. Soil C:N stoichiometry controls carbon sink partitioning between above-ground tree productivity and soil organic matter in high fertility forests

    Science.gov (United States)

    Cotrufo, M.; Alberti, G.; Vicca, S.; Inglima, I.; Belelli-Marchesini, L.; Genesio, L.; Miglietta, F.; Marjanovic, H.; Martinez, C.; Matteucci, G.; Peressotti, A.; Petrella, L.; Rodeghiero, M.

    2013-12-01

    The release of organic compounds from roots is a key process influencing soil carbon (C) dynamics and nutrient availability in terrestrial ecosystems and is a process by which plants stimulate microbial activity and soil organic matter (SOM) mineralization thus releasing nitrogen (N) to sustain their gross and net primary production (GPP and NPP). Root inputs also contribute to soil organic matter (SOM) formation. In this study, we quantified the annual net root derived C input to soil (Net-Croot) across six high fertile forests using an in-growth core isotope technique. On the basis of Net-Croot, wood and coarse root biomass changes and eddy covariance data, we quantified net belowground C sequestration. This and GPP were inversely related to soil C:N, but not to climate or age. Because, at these high fertile sites, biomass growth did not change with soil C:N ratio, biomass growth-to-GPP ratio significantly increased with increasing soil C:N. This was true for both our six forest sites and for high fertile sites across a set of other 23 sites selected at global scale. We suggest that, at high fertile sites, the interaction between plant demand for nutrients, soil stoichiometry and microbial activity sustain higher ecosystem C-sink allocation to above ground tree biomass with increasing soil C:N ratio and that this clear and strong relationship can be used for modelling forest C sink partitioning between plant biomass and soil. When C:N is high, microbes have a low C use efficiency, respire more of the fresh C inputs by roots and prime SOM decomposition increasing N availability for tree uptake. Soil C sequestration would therefore decrease, whereas the extra N released during SOM decomposition can promote tree growth and ecosystem C sink allocation in aboveground biomass. Conversely, C is sequestered in soil when the low soil C:N promotes microbial C use efficiency and new SOM formation.

  4. Ten Years of Near-Surface-Sensitive Satellite Observations of Carbon Dioxide and Methane: Selected Results Related to Natural and Anthropogenic Sources and Sinks

    Science.gov (United States)

    Buchwitz, M. A.; Reuter, M.; Schneising, O.; Bovensmann, H.; Burrows, J. P.

    2014-12-01

    Prior to the recently successfully launched OCO-2 mission, global near-surface-sensitive satellite observations of carbon dioxide (CO2) have been made with SCIAMACHY/ENVISAT during 2002-2012 and are still being made since 2009 with TANSO-FTS/GOSAT, which also deliver atmospheric methane (CH4). The SCIAMACHY and GOSAT overlapping time series of atmospheric column-averaged mole fractions, i.e., XCO2 and XCH4, now cover more than 10 years. During the last years significant progress has been made in improving the quality of the XCO2 and XCH4 data products retrieved from SCIAMACHY and GOSAT and in extending the time series so that more and more applications can be addressed. In this presentation we present some recent results related to CO2 and CH4 sources and sinks. The SCIAMACHY products have been generated using retrieval algorithms developed at University of Bremen. For XCO2 we use an ensemble of data products generated using GOSAT retrieval algorithms developed in Japan (at NIES), in the US (at NASA/JPL and collaborating institutes) and at European institutions (University of Leicester, UK, and SRON, Netherlands, in collaboration with KIT, Germany). Focus will be on three applications: (i) An assessment of the strength of the European terrestrial carbon sink during 2003-2010 based on an ensemble of SCIAMACHY (2003-2010) and GOSAT (2010) XCO2 data products, (ii) an assessment of CO2 and NO2 anthropogenic emission and emission ratio trends using co-located SCIAMACHY XCO2 and NO2 observations over Europe, North America and East Asia, and (iii) an analysis of SCIAMACHY XCH4 retrievals during 2006-2011 over North America focusing on fugitive methane emissions from oil and gas production using tight geological formations ("fracking"). It will be shown that (i) the European terrestrial carbon sink appears to be stronger than expected, (ii) that recent Chinese CO2 and NO2 emissions are increasing but with a trend towards reduced NO2-to-CO2 emission ratios pointing to

  5. The dynamic of the annual carbon allocation to wood in European tree species is consistent with a combined source-sink limitation of growth: implications for modelling

    Science.gov (United States)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrene, E.; Francois, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-05-01

    The extent to which wood growth is limited by carbon (C) supply (i.e. source control) or by cambial activity (i.e. sink control) will strongly determine the responses of trees to global changes. Nevertheless, the physiological processes that are responsible for limiting forest growth are still a matter of debate. The aim of this study was to evaluate the key determinants of the annual C allocation to wood along large soil and climate regional gradients over France. The study was conducted for five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). The drivers of stand biomass growth were assessed on both inter-site and inter-annual scales. Our data set comprised field measurements performed at 49 sites (931 site-years) that included biometric measurements and a variety of stand characteristics (e.g. soil water holding capacity, leaf area index). It was complemented with process-based simulations when possible explanatory variables could not be directly measured (e.g. annual and seasonal tree C balance, bioclimatic water stress indices). Specifically, the relative influences of tree C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in the stand C allocation to wood was predominantly driven by age-related decline. The direct effects of temperature and water stress on sink activity (i.e. effects independent from their effects on the C supply) exerted a strong influence on the annual stand wood growth in all of the species considered, including deciduous temperate species. The lagged effect of the past environmental conditions (e.g. the previous year's water stress and low C uptake) significantly affected the annual C allocation to wood. The C supply

  6. Analysis of Forestry Carbon Pool Characteristic and Carbon Sink Potential in China%我国森林碳库特点与森林碳汇潜力分析

    Institute of Scientific and Technical Information of China (English)

    杨帆; 刘金山; 贺东北

    2012-01-01

    森林生态系统在稳定全球碳循环和缓解全球气候变暖方面发挥着重要的作用,合理发展林业,可以实现固碳增汇,是缓解全球气候变化的重要措施。综述了森林碳库的重要地位、我国森林生态系统碳库特点,分析了通过增加森林面积和提高森林经营水平来增加森林碳汇的潜力。%Forest ecosystem plays an important role on stabling global carbon cycle and alleviating global war- ming. It can achieve carbon sequestration and increase forest carbon sink by rationally developing forest, it is an important measure to alleviate global climate change. The important position and its characteristic of forest car- bon pool in china were reviewed, and the carbon agement level was analyzed. sink potential by increasing forest area, improving forest man-agement level was analyzed.

  7. CVM Evaluation of Natural Forest Carbon Sinks in Ningbo%基于CVM的宁波天童天然林碳汇贸易研究

    Institute of Scientific and Technical Information of China (English)

    陈颖翱; 张勇

    2011-01-01

    以宁波天童天然林为例,探讨了将天然林碳汇纳入碳汇贸易的方法和途径,采用条件价值评估法(CVM)估算了天童天然林碳汇价值,并探讨了天然林碳汇贸易的可行性.结果表明:(1)与人工林碳汇相比,天然林碳汇在数量、生态功能和保育价值方面具优势,将天然林碳汇纳入碳汇贸易,是对现有人工林碳汇贸易的有益补充;(2)公众对碳汇贸易普遍持支持和偏好态度,但对碳汇概念认知程度低、对相关政策态度谨慎;(3)据CVM法评估得到天童天然林年均贸易价值合理值约1379万元/a,合2.06万元/t,高于人工林碳汇价格,反映公众对天然林整体生态功能和保护价值的较高支付意愿;(4)影响天然林碳汇价值因素为个人收入、概念了解度、政策支持度和责任的定位;(5)公众对天然林碳汇贸易高度关注、对保护天然林富有热情,所以天然林碳汇进行贸易具有社会基础和可行性.%Taking Tiantong Forest in Ningbo as an example, methods that integrated natural forest into carbon trade market by estimating its carbon sinks and politically feasibility via contingent valuation method (CVM) were discussed. Results indicated that natural forest which has advantages over planted forest in terms of quantity, ecological function and conservation value is a favorable supplement to bring natural forest into current carbon trade. The public supports and prefers natural forest while has limited knowledge of carbon sinks and conservative attitude toward relative policy. Via CVM, carbon sinks of Tiantong Forest is estimated as 13.79 million RMB, that is 20,600 RMB per ton which is higher than that of planted forest reflecting a public preference. Factors affecting WTP include personal income, understanding of related concept, support to the possible policies and awareness self-responsibility. Public awareness and support is the foundation to establish carbon trade of natural forest.

  8. {Stable isotope probing of the physical and biological controls that influence the fate and isotopic composition of carbon derived from the terrestrial methane sink }

    Science.gov (United States)

    Maxfield, P. J.; Hornibrook, E. R. C.; Dildar, N.; Evershed, R. P.

    2009-04-01

    Methane oxidizing bacteria (Methanotrophs) occur in every soil order, and are an important sink for atmospheric CH4 in well aerated soils. The quantity of C cycled via methanotrophic bacteria in soils is globally significant (Le Mer et al., 2001) yet the fate of methane derived carbon remains largely unknown and unquantified. There is generally good agreement regarding the magnitude of the soil CH4 sink determined by methane flux measurements and process modeling. More poorly characterised aspects of the soil CH4 sink include: (i) the physical and biological controls that influence the mechanism of CH4 oxidation in soils; (ii) the fate of oxidized CH4 carbon; (iii) the proportion of C from CH4 oxidation that is sequestered as organic C or released as CO2 (iv) the magnitude of kinetic isotope effects (KIEs) associated with high affinity methanotrophy in soils and the potential influence on the stable carbon isotope composition of atmospheric CH4. This research combines multiple stable isotope analytical approaches to investigate the magnitude, mechanism and pathways of the terrestrial methane sink. Principally 13CH4 stable isotope labeling techniques (Stable isotope probing; SIP) have been used to characterize and quantify methanotrophic populations in a range of different soils (Maxfield et al., 2006). Following 13CH4-incubations soil cores were removed for compound-specific C isotope analyses. Identification and quantification of methanotrophs was effectively achieved via the analysis of 13C-labelled phospholipid fatty acids (PLFAs) to link bacterial structure and function. It was also possible to identify the predominant controls influencing the active methanotrophic populations in both grassland and woodland soils (Maxfield et al., 2008). SIP can be combined with further isotopic analyses to facilitate a broader study of methanotroph C uptake and CH4 derived C sequestration. As SIP facilitates taxonomic assignments of the soil microorganisms involved in CH4 C

  9. Dissolution of calcite in the twilight zone: bacterial control of dissolution of sinking planktonic carbonates is unlikely.

    Directory of Open Access Journals (Sweden)

    Andrew Bissett

    Full Text Available We investigated the ability of bacterial communities to colonize and dissolve two biogenic carbonates (Foraminifera and oyster shells. Bacterial carbonate dissolution in the upper water column is postulated to be driven by metabolic activity of bacteria directly colonising carbonate surfaces and the subsequent development of acidic microenvironments. We employed a combination of microsensor measurements, scanning electron microscopy (SEM, confocal laser scanning microscopy (CLSM and image analysis and molecular documentation of colonising bacteria to monitor microbial processes and document changes in shell surface topography. Bacterial communities rapidly colonised shell surfaces, forming dense biofilms with extracellular polymeric substance (EPS deposits. Despite this, we found no evidence of bacterially mediated carbonate dissolution. Dissolution was not indicated by Ca²⁺ microprofiles, nor was changes in shell surface structure related to the presence of colonizing bacteria. Given the short time (days settling carbonate material is actually in the twilight zone (500-1000 m, it is highly unlikely that microbial metabolic activity on directly colonised shells plays a significant role in dissolving settling carbonates in the shallow ocean.

  10. Reconciling opposing views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystems as sources of atmospheric CO 2

    Science.gov (United States)

    Chen, Chen-Tung Arthur; Borges, Alberto V.

    2009-04-01

    Despite their moderately sized surface area, continental marginal seas play a significant role in the biogeochemical cycles of carbon, as they receive huge amounts of upwelled and riverine inputs of carbon and nutrients, sustaining a disproportionate large biological activity compared to their relative surface area. A synthesis of worldwide measurements of the partial pressure of CO 2 (pCO 2) indicates that most open shelves in the temperate and high-latitude regions are under-saturated with respect to atmospheric CO 2 during all seasons, although the low-latitude shelves seem to be over-saturated. Most inner estuaries and near-shore coastal areas on the other hand are over-saturated with respect to atmospheric CO 2. The scaling of air-sea CO 2 fluxes based on pCO 2 measurements and carbon mass-balance calculations indicate that the continental shelves absorb atmospheric CO 2 ranging between 0.33 and 0.36 Pg C yr -1 that corresponds to an additional sink of 27% to ˜30% of the CO 2 uptake by the open oceans based on the most recent pCO 2 climatology [Takahashi, T., Sutherland, S.C., Wanninkhof, R., Sweeney, C., Feely, R.A., Chipman, D., Hales, B., Friederich, G., Chavez, F., Watson, A., Bakker, D., Schuster, U., Metzl, N., Inoue, H.Y., Ishii, M., Midorikawa, T., Sabine, C., Hoppema, M., Olafsson, J., Amarson, T., Tilbrook, B., Johannessen, T., Olsen, A., Bellerby, R., De Baar, H., Nojiri, Y., Wong, C.S., Delille, B., Bates, N., 2009. Climatological mean and decadal change in surface ocean pCO 2, and net sea-air CO 2 flux over the global oceans. Deep-Sea Research II, this issue [doi: 10.1016/j.dsr2.2008.12.009].]. Inner estuaries, salt marshes and mangroves emit up to 0.50 Pg C yr -1, although these estimates are prone to large uncertainty due to poorly constrained ecosystem surface area estimates. Nevertheless, the view of continental shelves as sinks and near-shore ecosystems as sources of atmospheric CO 2 allows reconciling long-lived opposing views on carbon

  11. The characteristics of karst carbon sink in the Guijiang Catchment%桂江流域岩溶碳汇特征

    Institute of Scientific and Technical Information of China (English)

    黄奇波; 刘朋雨; 覃小群; 孔祥胜

    2011-01-01

    为研究岩溶区碳汇动态变化特征,使用德国Merck公司生产的碱度计每月定期对桂江流域14个岩溶大泉和16条地下河出口水中HCO3-含量进行了现场测定.结果表明桂江流域枯水期(11月至次年2月)地下水中HCO3-含量平均为223.62 mg/L,平水期(3月、9月)为222.11 mg/L,丰水期(4月至8月)为210.19 mg/L,枯水期和平水期的HCO3-平均含量比丰水期高13.43 mg/L和11.92 mg/L.尽管丰水期的HCO3-平均含量不及枯水期和平水期,但其平均流量最大,是平水期的2倍,枯水期的2.8倍,因此其岩溶碳汇量也最大,是平水期的4.7倍,是枯水期的2.7倍.在碳汇构成上,丰水期的岩溶碳汇量占年总碳汇量的63.13%,而平水期和枯水期只分别占年总碳汇量的13.35%和23.51%.%Karstification connects with global carbon circle closely. The erosion of carbonate can consume CO2 from atmosphere and soil air and convert them to HCO-3 in the water, therefore,the feature of karstification carbon sink can be got by way of HCOf monitoring in the water. The HCOr concentration from 14 large karst springs and 16 outlets of the underground river in the Guijiang Catchment are tested on filed monthly and regularly with the alkalimetermade by Merk Corporation. It is found that the average concentration of HCO-3 of groundwater is 223. 62 mg/L in low water level period (from November to February in the next year), 222.11 mg/L in normal water level period (in March and September) and 210. 19 mg/L in high water level period ( from April to August). Although the mean concentration of HCO-3 in high water level period is lower than that in normal water level period, but the discharge in high water level period is highest, which is twice more than that in normal water level period and 2. 8 times as many as that in low water level period, so the carbon sink in high water level period is 4. 7 and 2. 7 times more than that in normal and low water level periods, and the carbon sink

  12. Dynamic changes and driving factors analysis of carbon source and carbon sink in Shandong province%山东省碳源与碳汇的动态变化及驱动因子分析

    Institute of Scientific and Technical Information of China (English)

    肖玲; 赵先贵; 许华兴

    2013-01-01

    IPCC method was adopted to study the dynamic variation of carbon source and carbon sink in Shandong province. Conclusions are as follows; carbon source increased from 59 456. 08 × 104 t to 144 961. 60×104 t year by year in Shandong province from 2000 to 2010,with an annual growth rate of 13. 07%; Besides, carbon source per capita increased from 6. 61 t to 15.13 t. Carbon source per unit area increased form 37. 68 t/hm2 to 91. 86 t/hm2, and then carbon source per ten thousand Yuan GDP dropped from 3. 63 t to 2. 88 t, which showed continuous improvement of energy utilization. During the same period, carbon sink dropped from 4 519. 03×104 t to 4 230.18×104 t, decreased by 6. 4%. At the same time, carbon sink per capita fell from 0. 50 t to 0. 44 t,and carbon sink per unit area decreased from 2.86 t/hm2 to 2. 68 t/hm2. Because the carbon source is larger than the carbon sink, the net carbon source increased from 54 937. 05 × 104 t to 140 731. 42 × 104 t, reaching a growth rate of 156. 17%. Accordingly, the net carbon source per capita in Shandong province is 3-7 times higher than the goal of global climate change, as well as higher than the average of China, and yet a little lower than that of the United States only. Furthermore, the net carbon source per unit area is 31. 08~79. 63 times higher than the goal of global climate changes, too. The results show that it is a carbon sink from a view of overall external performance in Shandong province, facing a very difficult task of carbon emission reduction. In terms of the driving factors of continual carbon increased resource, it is mainly due to the high proportion of secondary industry in the industry structure, as well as the high carbon characteristics of industry system. Besides, high-carbon energy such as the coal accounts for a large proportion of energy consumption structure, making up another driving factor for continual carbon resource.%采用IPCC方法研究了山东省碳源与碳汇的

  13. Analysis of Forest Carbon sink Market From the Perspective of Market player%从市场主体角度探析森林碳汇市场发展

    Institute of Scientific and Technical Information of China (English)

    王杏芝; 高建中

    2011-01-01

    The main body of forest carbon sinks includes demanders, suppliers and third - party independent certification body. Based on the current situation of the main body constitutes of forest carbon sink market from background of global warming, The article illustrated impacts of forest carbon sink market players on forest carbon sink market from three aspects, as high transaction costs, lack of liquidity and irrational competition. Suggestions which are establishment of the trading system for market conditions, cultivating the domestic market, and actively monitoring and guiding role of the government' s have been proposed.%森林碳汇市场的主体包括需求者、供给者和第三方独立认证机构.文章从目前全球变暖的大背景下森林碳汇市场的主体构成状况,即较高的交易成本,缺乏流动性,不合理的市场竞争3个方面阐述了森林碳汇市场主体对森林碳汇市场的影响.提出了建立适合市场状况的交易体系,培育国内需求市场,积极发挥政府的监管和引导作用等对我国发展碳汇市场的建议.

  14. Ion association in water solution of soil and vadose zone of chestnut saline solonetz as a driver of terrestrial carbon sink

    Science.gov (United States)

    Batukaev, Abdul-Malik A.; Endovitsky, Anatoly P.; Andreev, Andrey G.; Kalinichenko, Valery P.; Minkina, Tatiana M.; Dikaev, Zaurbek S.; Mandzhieva, Saglara S.; Sushkova, Svetlana N.

    2016-03-01

    The assessment of soil and vadose zone as the drains for carbon sink and proper modeling of the effects and extremes of biogeochemical cycles in the terrestrial biosphere are the key components to understanding the carbon cycle, global climate system, and aquatic and terrestrial system uncertainties. Calcium carbonate equilibrium causes saturation of solution with CaCO3, and it determines its material composition, migration and accumulation of salts. In a solution electrically neutral ion pairs are formed: CaCO30, CaSO40, MgCO30, and MgSO40, as well as charged ion pairs CaHCO3+, MgHCO3+, NaCO3-, NaSO4-, CaOH+, and MgOH+. The calcium carbonate equilibrium algorithm, mathematical model and original software to calculate the real equilibrium forms of ions and to determine the nature of calcium carbonate balance in a solution were developed. This approach conducts the quantitative assessment of real ion forms of solution in solonetz soil and vadose zone of dry steppe taking into account the ion association at high ionic strength of saline soil solution. The concentrations of free and associated ion form were calculated according to analytical ion concentration in real solution. In the iteration procedure, the equations were used to find the following: ion material balance, a linear interpolation of equilibrium constants, a method of ionic pairs, the laws of initial concentration preservation, operating masses of equilibrium system, and the concentration constants of ion pair dissociation. The coefficient of ion association γe was determined as the ratio of ions free form to analytical content of ion γe = Cass/Can. Depending on soil and vadose zone layer, concentration and composition of solution in the ionic pair's form are 11-52 % Ca2+; 22.2-54.6 % Mg2+; 1.1-10.5 % Na+; 3.7-23.8 HCO3-, 23.3-61.6 % SO42-, and up to 85.7 % CO32-. The carbonate system of soil and vadose zone water solution helps to explain the evolution of salted soils, vadose and saturation zones, and

  15. 上海地区土壤碳汇功能评估%Evaluation of Soil Carbon Sinks in Shanghai

    Institute of Scientific and Technical Information of China (English)

    赵敏; 胡静; 汤庆合

    2012-01-01

    With the rapid development of urbanization,the land use changes had been intensified,which affected soil organic carbon stock.To explore how urbanization effected on soil carbon sequestration,taking Shanghai as example,which was the most rapid development of urbanization in China,the second soil survey data of Shanghai,the farmland survey data in Shanghai between the year 2004 and the year 2005 ,and the field sampling in the year 2009 were used to analyze the variation characters of soil organic carbon.It was found that the average content of soil organic carbon did not change significantly,but the soil organic carbon pool decreased.Thereby,the soil worked as a kind of carbon source,rather than carbon.It was the obvious features of the urbanization to land use changes that the planting structure changed from rice fields to dry land crops for planting vegetable,fruit,and seedlings in some suburban areas.While the organic carbon contents of paddy soil were higher than that of forest and vegetable garden,so planting structure changes had a major impact on soil organic carbon content.Mean while,farming systems,tillage pattern,fertilizer and other agricultural management practices also influenced the changes of soil organic carbon content.As far as the urban green space,it did not make up the loss of soil organic carbon lead by urbanization.%利用上海市第二次土壤普查资料,2004年-2005年上海耕地地力调查资料,以及2009年实地调查采样、实验分析获得的数据,研究了3个时期上海土壤有机碳的变化特征.结果表明,20多年来上海土壤有机碳平均含量没有明显变化,土壤有机碳库逐渐减小,从而使得上海城市化过程中土壤成为一种碳源,而不是碳汇.城市郊区以扩大蔬菜、果树、苗木种植为特征的旱地作物种植方式代替水稻田,是城市化影响土地利用类型变化的明显特征,而水稻田土壤有机碳含量高于林地、菜地.种植结构的变化对土壤

  16. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Pr...

  17. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  18. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea’s oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  19. Estimation and spatial-temporal characteristics of carbon sink in the arid region of northwest China%中国西北干旱区植被碳汇估算及其时空格局

    Institute of Scientific and Technical Information of China (English)

    潘竟虎; 文岩

    2015-01-01

    Global warming caused by greenhouse gas emissions has had a profound impact on human survival and development. Consequently, this phenomenon has received widespread attention from the international community. Vegetation can absorb greenhouse gases CO2 , and has a huge carbon sink function, so it has an irreplaceable role in slowing global warming. The carbon sink capacity of vegetation has a significant impact on regional and global climate change. Carbon emissions are undoubtedly enormous in the mid and high latitudes of the Northern Hemisphere, so studies on terrestrial ecosystem carbon dynamics and spatial patterns in the arid region of northwest China may provide an accurate assessment how China contributes towards mitigating global climate change and CO2 emission reduction. The net primary productivity (NPP) and heterotrophic respiration (RH) in the arid region of northwest China were calculated by using MODIS images, meteorological data, and a vegetation type map, in combination with an improved CASA model and soil microbial respiration model. The NPP and RH were then used to estimate net ecosystem productivity (NEP) and vegetation carbon sink from 2001 to 2012. Spatial-temporal characteristics and the reasons for NPP and carbon sink variation in the arid region of northwest China were analyzed. The results show that research methods used in this paper were able to quickly extract ecosystem net primary productivity and carbon sink for the northwest arid region. The methods used are efficient, convenient, and practical for large scale carbon balance and carbon cycling studies in this region. Comparison indicated small gaps between simulated and measured site values. The overall difference in the spatial distribution between simulated values and MODIS NPP products is also small, and the volatility of the analog value is less than the value of MODIS NPP products. NPP in the study area showed strong seasonal variation. The maximal NPP value was obtained in July

  20. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    Science.gov (United States)

    Pozzato, L.; Van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J. J.

    2013-06-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient in these sediments. Moreover, metazoans directly consume labile particulate organic matter resources and thus compete with bacteria for phytodetritus.

  1. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    L. Pozzato

    2013-06-01

    Full Text Available The bacterial loop, the consumption of dissolved organic matter (DOM by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient in these sediments. Moreover, metazoans directly consume labile particulate organic matter resources and thus compete with bacteria for phytodetritus.

  2. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    OpenAIRE

    Pozzato, L.; van Oevelen, D.; Moodley, L; Soetaert, K.; Middelburg, J. J.

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ) to study the importance of the microbial loop...

  3. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

    Science.gov (United States)

    Pozzato, L.; Van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J. J.

    2013-11-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea's oxygen minimum zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the 7 day experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient, in sediments both inside and outside the OMZ. Moreover, metazoans directly consumed labile particulate organic matter resources and thus competed with bacteria for phytodetritus.

  4. 企业购买林业碳汇指标意愿的影响因素分析∗%Analysis of Enterprises’ Intention and Influence Factors of Forestry Carbon Sink Purchase

    Institute of Scientific and Technical Information of China (English)

    陈丽荣; 曹玉昆; 朱震锋; 苏蕾

    2016-01-01

    基于332家企业的问卷调查数据,运用结构方程模型探讨了影响企业购买林业碳汇意愿的因素及其之间的关系。研究结果表明:企业碳汇认知度对企业购买意愿具有显著的正面影响;国家政策导向对提高企业购买林业碳汇意愿具有显著作用;企业家选择偏好对企业购买意愿有显著的正面影响;企业感知收益对购买意愿没有显著影响。并据此提出相关政策建议:积极发挥国家政策的正面效应,制定提高企业购买林业碳汇意愿的相关政策;落实宣传载体,加大林业碳汇宣传和培训力度,提高企业林业碳汇认知度;充分发挥企业家选择偏好对林业碳汇的正面影响,制定灵活便捷的林业碳汇自愿交易规则,大力宣传林业碳汇多重效益,扩大林业碳汇自愿交易规模。%Based on questionnaire data from 332 enterprises, this study uses structural equation model to discuss the influence factors of enterprises�� intention to purchase forestry carbon sink and the rela-tionship between them. The results show that enterprises�� awareness of carbon sink has a significant positive impact on purchase intention; national policy guidance has significant positive effect to en-hance enterprises��intention to purchase forestry carbon sink; entrepreneur preference has a significant positive impact on enterprises�� purchase intention; and enterprises perceived benefit has no significant effect on purchase intention. And corresponding policy recommendations are proposed: actively pla-ying the positive effect of national policy and formulating policies to improve enterprises�� intention of forestry carbon sink purchase; implementing propaganda carrier to enhance publicity and training ef-forts for forestry carbon sink and improve enterprises��awareness of carbon sink; and giving full play to the positive impact of entrepreneur preference on forestry carbon sink

  5. Advancing Understanding of the Role of Belowground Processes in Terrestrial Carbon Sinks trhrough Ground-Penetrating Radar. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Day, Frank P. [Old Dominion Univ., Norfolk, VA (United States)

    2015-02-06

    Coarse roots play a significant role in belowground carbon cycling and will likely play an increasingly crucial role in belowground carbon sequestration as atmospheric CO2 levels continue to rise, yet they are one of the most difficult ecosystem parameters to quantify. Despite promising results with ground-penetrating radar (GPR) as a nondestructive method of quantifying biomass of coarse roots, this application of GPR is in its infancy and neither the complete potential nor limitations of the technology have been fully evaluated. The primary goals and questions of this study fell into four groups: (1) GPR methods: Can GPR detect change in root biomass over time, differentiate live roots from dead roots, differentiate between coarse roots, fine roots bundled together, and a fine root mat, remain effective with varied soil moisture, and detect shadowed roots (roots hidden below larger roots); (2) CO2 enrichment study at Kennedy Space Center in Brevard County, Florida: Are there post-fire legacy effects of CO2 fertilization on plant carbon pools following the end of CO2application ? (3) Disney Wilderness Study: What is the overall coarse root biomass and potential for belowground carbon storage in a restored longleaf pine flatwoods system? Can GPR effectively quantify coarse roots in soils that are wetter than the previous sites and that have a high percentage of saw palmetto rhizomes present? (4) Can GPR accurately represent root architecture in a three-dimensional model? When the user is familiar with the equipment and software in a setting that minimizes unsuitable conditions, GPR is a relatively precise, non-destructive, useful tool for estimating coarse root biomass. However, there are a number of cautions and guidelines that should be followed to minimize inaccuracies or situations that are untenable for GPR use. GPR appears to be precise as it routinely predicts highly similar values for a given area across multiple

  6. Conceptual Framework of Carbon Sequestration Rate and Potential Increment of Carbon Sink of Regional Terrestrial Ecosystem and Scientific Basis for Quantitative Carbon Authentification%区域尺度陆地生态系统固碳速率和增汇潜力概念框架及其定量认证科学基础

    Institute of Scientific and Technical Information of China (English)

    于贵瑞; 王秋凤; 刘迎春; 刘颖慧

    2011-01-01

    It is not only an urgent need for mitigating global climate change to study the carbon sequestration rate,potential increment of carbon sink of regional terrestrial ecosystem and its quantitative authentification,but also the core task of carbon cycle research in earth system,and the scientific foundation of terrestrial ecosystem management.In the past two decades,vast research have been done at home and abroad,and a lot of feasible techniques for increasing carbon sink have been developed in the practice of carbon management.Meanwhile,many concepts of carbon sequestration rate and potential increment of carbon sink of terrestrial ecosystem,and methods for carbon accounting and authentification have been put forward based on different demands and sub-jects.Due to lacking systematic and sufficient discussion,large discrepancy exists in the understanding of relat-ed concepts among different sections and subjects,which leads to the concept confusion and the difficulty in the standardization of accounting methods.In this paper,related concepts such as carbon storage,carbon sequestra-tion rate,and carbon sequestration potential of ecosystem were expounded systematically based on the basic con-cept of carbon sequestration of terrestrial ecosystem;practical potential of carbon sequestration,socioeconomic potential of carbon sequestration,technical potential of carbon sequestration,theoretical potential of carbon se-questration,and the potential of carbon sequestration ratified by Kyoto Protocol were analyzed based on the real-izability of the techniques for increasing carbon sink;and the scientific foundation,limitation and uncertainty of different methods for authenticating,analyzing,and assessing carobn sink,such as time continuous inventory method,space for time reference method,and limited factor analysis method as well,were expatiated finally.The final goal of this paper is to arouse the attention of academe and related sections,to promote the standardiza-tion in

  7. Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM

    Directory of Open Access Journals (Sweden)

    C. Rödenbeck

    2015-08-01

    Full Text Available Using measurements of the surface-ocean CO2 partial pressure (pCO2 and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM initiative, variations in regional and global sea–air CO2 fluxes have been investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV, all mapping methods estimate the largest variations to occur in the Eastern equatorial Pacific. Despite considerable spead in the detailed variations, mapping methods with closer match to the data also tend to be more consistent with each other. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009, which is larger than simulated by biogeochemical process models. On a decadal perspective, the global CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to 2000. The weighted mean total ocean CO2 sink estimated by the SOCOM ensemble is consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trends.

  8. Identification of carbohydrates as the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta) and optimization of its productivity by nitrogen manipulation.

    Science.gov (United States)

    Wang, Hai-Tao; Yao, Chang-Hong; Ai, Jiang-Ning; Cao, Xu-Peng; Xue, Song; Wang, Wei-liang

    2014-11-01

    Microalgae represent a potential feedstock for biofuel production. During cultivation under nitrogen-depleted conditions, carbohydrates, rather than neutral lipids, were the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta). Carbohydrates reached maximum levels of 21.2 pg cell(-1) on day 5, which was an increase of more than 7-fold from day 1, while neutral lipids simultaneously increased 1.9-fold from 4.0 to 7.6 pg cell(-1) during the ten-day nitrogen-depleted cultivation. The carbohydrate productivity of I. zhangjiangensis was improved by optimization of the nitrate supply mode. The maximum carbohydrate concentration was 0.95 g L(-1) under batch cultivation, with an initial nitrogen concentration of 31.0 mg L(-1), which was 2.4-fold greater than that achieved under nitrogen-depleted conditions. High performance liquid chromatography (HPLC) analysis showed that the accumulated carbohydrate in I. zhangjiangensis was composed of glucose. These results show that I. zhangjiangensis represents an ideal carbohydrate-enriched bioresource for biofuel production.

  9. Enhanced ozone strongly reduces carbon sink strength of adult beech (Fagus sylvatica) - Resume from the free-air fumigation study at Kranzberg Forest

    Energy Technology Data Exchange (ETDEWEB)

    Matyssek, R., E-mail: matyssek@wzw.tum.d [Ecophysiology of Plants, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Wieser, G. [Dept. Alpine Timberline Ecophysiology, Federal Office and Research Centre for Forests, Rennweg 1, A-6020 Innsbruck (Austria); Ceulemans, R. [Dept. of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Rennenberg, H. [Tree Physiology, Institute of Forest Botany and Tree Physiology, University of Freiburg, Georges-Koehler-Allee 53, D-79110 Freiburg (Germany); Pretzsch, H. [Forest Growth and Yield Sciences, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Haberer, K. [Tree Physiology, Institute of Forest Botany and Tree Physiology, University of Freiburg, Georges-Koehler-Allee 53, D-79110 Freiburg (Germany); Loew, M.; Nunn, A.J. [Ecophysiology of Plants, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Werner, H. [Ecoclimatology (formerly: Bioclimatology and Air Pollution Research), Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Wipfler, P. [Forest Growth and Yield Sciences, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Osswald, W. [Phytopathology of Woody Plants, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Nikolova, P. [Ecophysiology of Plants, Technische Universitaet Muenchen, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising (Germany); Hanke, D.E. [Dept. Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA (United Kingdom); Kraigher, H. [Slovenian Forestry Institute, Forest Biology, Ecology and Technology, Vecna pot 2, 1000 Ljubljana (Slovenia); Tausz, M. [Dept. of Forest and Ecosystem Science, Melbourne School of Land and Environment, Water Street, Creswick Vic 3363 (Australia)

    2010-08-15

    Ground-level ozone (O{sub 3}) has gained awareness as an agent of climate change. In this respect, key results are comprehended from a unique 8-year free-air O{sub 3}-fumigation experiment, conducted on adult beech (Fagus sylvatica) at Kranzberg Forest (Germany). A novel canopy O{sub 3} exposure methodology was employed that allowed whole-tree assessment in situ under twice-ambient O{sub 3} levels. Elevated O{sub 3} significantly weakened the C sink strength of the tree-soil system as evidenced by lowered photosynthesis and 44% reduction in whole-stem growth, but increased soil respiration. Associated effects in leaves and roots at the gene, cell and organ level varied from year to year, with drought being a crucial determinant of O{sub 3} responsiveness. Regarding adult individuals of a late-successional tree species, empirical proof is provided first time in relation to recent modelling predictions that enhanced ground-level O{sub 3} can substantially mitigate the C sequestration of forests in view of climate change. - Empirical proof corroborates substantial mitigation of carbon sequestration in the tree-soil system of a forest site under enhanced O{sub 3} impact for adult beech.

  10. Photosynthesis, respiration, and carbon turnover in sinking marine snow from surface waters of Southern California Bight: implications for the carbon cycle in the ocean

    DEFF Research Database (Denmark)

    Ploug, H.; Grossart, HP; Azam, F.

    1999-01-01

    aggregate in darkness, which yielded a turnover time of 8 to 9 d for the total organic carbon in aggregates. Thus, marine snow is not only a vehicle for vertical flux of organic matter; the aggregates are also hotspots of microbial respiration which cause a fast and efficient respiratory turnover...... of particulate organic carbon in the sea....

  11. Flux rates for water and carbon during greenschist facies metamorphism: implications for the role of orogenic belts as a source/sink for atmospheric CO2

    Science.gov (United States)

    Skelton, A.

    2010-12-01

    The time-averaged flux rate for a CO2-bearing hydrous fluid during greenschist facies regional metamorphism was estimated to 10-10.2 ± 0.4 m3.m-2.s-1. This was evaluated by combining 1) Peclet numbers obtained by chromatographic analysis of the propagation of reaction fronts in 33 metamorphosed basaltic sills in the SW Scottish Highlands, 2) empirical diffusion rates for CO2 in water obtained by Wark & Watson (2003), and 3) calculated time-averaged metamorphic porosities. The latter were calculated using an expression obtained by combining estimated Peclet numbers with the empirical porosity - permeability relationships obtained by Wark and Watson (1998) and Price et al. (2006) and Darcy’s law. This approach yielded a time-averaged metamorphic porosity of 10-2.6 ± 0.2 for greenschist facies conditions. The corresponding timescale for metamorphic fluid flow was 103.6 ± 0.1 years. By using mineral assemblages to constrain fluid compositions, I further obtained a time-averaged annual flux rate for carbon of 0.5-7 mol-C.m-2.yr-1. This matches measured emission rates for metamorphic CO2 from orogenic hot springs. These fluxes significantly exceed estimated rates of CO2 drawdown by orogenic silicate weathering and therefore indicate that orogenic belts are a source rather than a sink of atmospheric CO2. Thin section in XPL showing replacement of amphibole by calcite recording syn-metamorphic carbonation of a metamorphosed basaltic sill in the SW Scottish Highlands.

  12. Global Analysis of Carbon Sources and Sinks with a Comprehensive Model Optimized with GOSAT/Tanso Observations

    Science.gov (United States)

    Denning, A.; Lokupitiya, R. S.; Zupanski, D.; Kawa, S. R.; Baker, D. F.; Doney, S. C.; Gurney, K. R.

    2009-12-01

    We present a system to analyze GOSAT/Tanso data using a combination of existing models of CO2 exchanges due to hourly photosynthesis and respiration, daily air-sea gas exchange, biomass burning, Fossil Fuel Emissions, and atmospheric transport. This comprehensive system allows direct comparison to the observed record of both in-situ and remotely sensed atmospheric CO2 at hourly timescales. We have previously demonstrated that a lower-resolution version of the system has good skill at replicating diurnal, synoptic, and seasonal variations over vegetated land surfaces. The system is driven by meteorological output from the NASA Goddard EOS Data Assimilation System, version 5. Surface weather from the system drives calculations of terrestrial ecosystem metabolism (radiation, precipitation, humidity, temperature) and air-sea gas exchange (wind), with other input data coming from satellite data products (e.g., fPAR and LAI from MODIS, and ocean color from SeaWiFS and MODIS). The analysis system is evaluated using synthetic data on a 2 x 2.5 degree (lat x lon) global grid. Synthetic data are sampled in cloud-free columns along the GOSAT orbital ephemeris and used to estimate multiplicative biases to component fluxes by Ensemble Data Assimilation. The system is quite successful at retrieving mechanistic estimates of spatial patterns of surface carbon fluxes on monthly and annual timescales over land, but is less skillful over the oceans.

  13. Moderate topsoil erosion rates constrain the magnitude of the erosion-induced carbon sink and agricultural productivity losses on the Chinese Loess Plateau

    Science.gov (United States)

    Zhao, Jianlin; Van Oost, Kristof; Chen, Longqian; Govers, Gerard

    2016-08-01

    Despite a multitude of studies, overall erosion rates as well as the contribution of different erosion processes on Chinese Loess Plateau (CLP) remain uncertain, which hampers a correct assessment of the impact of soil erosion on carbon and nutrient cycling as well as on crop productivity. In this paper we used a novel approach, based on field evidence, to reassess erosion rates on the CLP before and after conservation measures were implemented (1950 vs. 2005). We found that current average topsoil erosion rates are 3 to 9 times lower than earlier estimates suggested. Under 2005 conditions, more sediment was produced by non-topsoil erosion (gully erosion (0.23 ± 0.28 Gt yr-1) and landsliding (0.28 ± 0.23 Gt yr-1) combined) than by topsoil erosion (ca. 0.30 ± 0.08 Gt yr-1). Overall, these erosion processes mobilized ca. 4.77 ± 1.96 Tg yr-1 of soil organic carbon (SOC): the latter number sets the maximum magnitude of the erosion-induced carbon sink, which is ca. 4 times lower than one other recent estimate suggests. The programs implemented from the 1950s onwards reduced topsoil erosion from 0.51 ± 0.13 to 0.30 ± 0.08 Gt yr-1 while SOC mobilization was reduced from 7.63 ± 3.52 to 4.77 ± 1.96 Tg C yr-1. Conservation efforts and reservoir construction have disrupted the equilibrium that previously existed between sediment and SOC mobilization on the one hand and sediment and SOC export to the Bohai sea on the other hand: nowadays, most eroded sediments and carbon are stored on land. Despite the fact that average topsoil losses on the CLP are still relatively high, a major increase in agricultural productivity has occurred since 1980. Fertilizer application rates nowadays more than compensate for the nutrient losses by (topsoil) erosion: this was likely not the case before the dramatic rise of fertilizer use that started around 1980. Hence, erosion is currently not a direct threat to agricultural productivity on the CLP but the long-term effects of erosion on

  14. Nitrate isotopes illuminate the black box of paddy soil biogeochemistry: water and carbon management control nitrogen sources and sinks

    Science.gov (United States)

    Wells, N. S.; Clough, T. J.; Johnson-Beebout, S. E.; Buresh, R. J.

    2010-12-01

    Accurate prediction of the available nitrogen (N) pool in submerged paddy soils is needed in order to produce rice, one of the world’s most essential crops, in an economically and environmentally sustainable manner. By applying emerging nitrate dual-isotope (δ15N- δ18O- NO3-) techniques to paddy systems, we were able to obtain a unique process-level quantification of the synergistic impacts of carbon (C) and water management on N availability. Soil and water samples were collected from fallow experimental plots, with or without organic C amendments, that were maintained under 1 of 3 different hydrologic regimens: continuously submerged, water excluded, or alternate wetting and drying. In continuously submerged soils the δ15N-NO3- : δ18O-NO3- signal of denitrification was not present, indicating that there was no N attenuation. Biological nitrogen fixation (BNF) was the dominant factor in defining the available N pool under these conditions, with δ15N-NO3- approaching atmospheric levels as size of the pool increased. Using an isotope-based pool-mixing model, it was calculated that 10±2 µg N g-1 soil were contributed by BNF during the fallow. A lack of BNF combined with removal via denitrification (δ15N-NO3- : δ18O-NO3- = 1) caused relatively lower available N levels in dried and alternate wetting-drying soils during this period. Magnitude and net impact of denitrification was defined by the extent of drying and C availability, with rice straw C additions driving tighter coupling of nitrification and denitrification (δ15N:δ18O straw amendments ultimately retained a significantly larger available N pool due to enhanced input from soil organic matter. These findings underline the necessity of, and validate a new means for, accurate quantification micro-scale biogeochemical interactions for developing farm-scale management practices that can maximize N storage and minimize environmentally undesirable losses.

  15. The sedimentary carbon sink as a climate regulator: Towards a better description of organic matter degradation dynamics in Cretaceous black shales

    Science.gov (United States)

    Arndt, Sandra; Larowe, Doug; Brumsack, Hans-Juergen

    2010-05-01

    Cretaceous sediments are characterized by sequences of organic carbon-rich black shales, repeatedly deposited on a basin-wide or even global scale. However, the mechanisms that triggered the enhanced organic matter burial in the Cretaceous ocean remain ellussive. In particular, a detailed understanding and quantification of organic matter degradation in Cretaceous black shales and its effect on the ocean-atmosphere system is still missing. Yet, such an understanding is indispensable for a better assessment of Cretaceous climate change. Here, a reaction-transport model was used to infer the long-term evolution of anaerobic organic matter degradation in Cretaceous black shales from the distribution of authigenic barite in sediments drilled at Demerara Rise (ODPLeg207, Site1258). Fully transient simulations were performed over a period of 100 Myrs. The inversely determined parameters reveal that the reactivity of the organic matter was already low at the time of its deposition in the Cretaceous, implying a high preservation efficiency of organic matter (between 79% and 89%) within the black shale layers. Geochemical characteristics of the drilled sediments, as well as the presence of specific biomarkers, suggest that this low reactivity is most likely the consequence of the euxinic palaeo-conditions favoring the sulfurization of the organic matter. These findings reveal that the extreme environmental conditions that prevailed in the Cretaceous greenhouse increased the importance of factors that favor organic matter preservation. Consequently, the functioning of the Cretaceous sedimentary carbon sink and its effect on the Cretaceous climate system may not be well-described by the existing organic carbon degradation models. Therefore, the results emphasize the need for a generic and mechanstic model that unambiguously relates the fate of organic matter to factors such as the type and composition of the depositional environment, the microbial community structure and the

  16. Carbon Sink Function of Filter-feeding Fish in Freshwater Fisheries%滤食性鱼类在淡水渔业中的碳汇作用初探

    Institute of Scientific and Technical Information of China (English)

    陈中祥; 牟振波

    2011-01-01

    气候变暖威胁人类的生存与发展,减少CO2等温室气体的排放,发展低碳经济,缓解全球气候变暖的低碳经济是人类的共识。滤食性鱼类通过滤食浮游生物,间接降低大气中的CO2浓度而发挥碳汇作用。本文描述了一个不投饵的淡水生态系统的碳循环,探讨了滤食性鱼类在淡水生态系统中的碳汇作用,依据2009年全国水产养殖相关统计数据,估算了全国滤食性鱼类养殖的年碳汇量,为淡水渔业的低碳发展提供新思路,以推进现代化渔业的科学健康发展。%Climate warming has been a world-concerned global problem.It brings a series of serious consequences,greatly impacts human survival and development.To reduce carbon dioxide emissions and mitigate global warming,the development of the low carbon economy based on low energy consumption,low pollution and low emission has been our common sense.Fixing and sequestrating greenhouse gases by biological carbon sink is one of the most economical and effective ways.By filtering plankton,filter-feeding fish can reduce indirectly atmospheric carbon dioxide concentration and exert carbon sink function.The paper described carbon cycle of freshwater ecosystem without feeding,and presented carbon sink function of filter-feeding fish.At last,carbon sink amount of filter-feeding fish is evaluated based on 2009 relevant statistics of Chinese aquaculture.The research will make a good preparation for low carbon development of freshwater fisheries,and impel the scientific and healthy development of modern fisheries.

  17. A Review of Overseas Remote Sensing Monitoring Methods for Aboveground Forest Carbon Sink%国外森林地上部分碳汇遥感监测方法综述

    Institute of Scientific and Technical Information of China (English)

    黄从红; 张志永; 张文娟; 杨军

    2012-01-01

    森林的碳汇功能对缓解气候变化具有重要作用,森林碳汇的计量和监测方法备受关注,其中应用遥感方法对森林地上部分碳汇进行监测计量已经成为目前林业遥感的热点。文中基于光学遥感、微波雷达和激光雷达3种常用的遥感数据源综述了国外森林地上部分碳汇遥感监测的主要方法,并讨论了这些监测方法的精度和不确定性。得出:1)基于光学遥感数据的多元回归分析法在森林地上部分碳汇估算中应用最为广泛,人工神经网络法具有更高的估算精度;2)微波雷达系统能够穿透云层,可用于多云地区森林地上部分碳汇的估算;3)基于激光雷达数据的估算结果是三者中精度最高的。可用于高生物量地区森林地上部分碳汇的监测。%Forest carbon sink is important for mitigating the climate change. Therefore the methods for quantifying and monitoring of forest carbon sink have attracted great attentions. Among them, monitoring the aboveground forest carbon sink with remote sensing has become a hotspot in the research of forest remote sensing. This article reviewed the main methods that foreign countries adopt to monitor the aboveground forest carbon sink with remote sensing based on three types of remote sensing data (i. e. , optical sensor data, Radar data and Lidar data). Then we discussed the accuracy and uncertainty of these monitoring methods with remote sensing techniques. We reached the following conclusions: 1) The multiple regression analysis method with optical remote sensing data is the most common method in estimating the aboveground forest carbon sink, while the artificial neural network method tends to produce more accurate results than the multiple regression analysis method; 2) Radar system has the ability to penetrate cloud cover, so it can be used to estimate the aboveground forest carbon sink in cloudy areas; and 3 ) The accuracy of estimating results

  18. Study on Current Characteristics of Carbon Sink/Source in Farm and Ecosystem in Xingwen County%四川兴文县农田生态系统碳源/汇现状特征研究

    Institute of Scientific and Technical Information of China (English)

    陈勇; 税伟; 李首成; 康银红

    2012-01-01

    采用2003 ~2010年四川省兴文县农业投入和产出相关农业数据,对农田生态系统的碳源/汇现状特征进行了研究.结果表明:①2003~2010年兴文县农田生态系统碳吸收量呈持续增加趋势,2010年碳吸收量达183 487.22 t,比2003年提高了8.76%.②2003 ~2010年兴文县农田生态系统排放量总体呈增加的趋势,从2003年的10443.06t增加到2010年的11955.70t,化肥施用是导致碳损失的主要途径.③兴文县表田生态系统的碳吸收大于碳排放,具有较强的碳汇能力,但碳排放的增长大于碳吸收的增长,对农田碳汇培育形式压力.%Rased or the statistic data of agricultural input and output in Xingwen county from 2003 to 2010, and the current characteristics of carbon sink/source in farmland ecosystem were analyzed. The result showed that ( i ) The amounts of carbon absorption in farmland ecosystem in Xingwen kept stable increase since 2003. The amounts of carbon absorption were 183487.22 t in 2010, increasing by 8. 76 % than that in 2003. ( ii ) The amounts of carbon emission in farmland ecosystem in Xingwen totally kept the increasing trend, which increased from 10443.06 tons in 2003 to 11955.70 tons in 2010, and the inpvts of fertilizer were the main way of carbon loss. (iii) as carbon absorption was higher than carbon emission, farmland ecosystem had strong capability of carbon sink, but there still existed pressure to increasing carbon sink in farmland ecosystem in Xingwen because the growth rate of carbon emission was higher than that of carbon absorption.

  19. Microchannel heat sink assembly

    Science.gov (United States)

    Bonde, Wayne L.; Contolini, Robert J.

    1992-01-01

    The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watetight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures.

  20. 岩石风化碳汇研究的最新进展和展望%New progress and prospects in the study of rock-weathering-related carbon sinks

    Institute of Scientific and Technical Information of China (English)

    刘再华

    2012-01-01

    自气候变化的岩石风化控制学说提出至今,学界普遍认为,是硅酸盐的化学风化碳汇作用在控制着长时间尺度的气候变化,而在短时间尺度上硅酸盐风化碳汇与碳酸盐风化碳汇也是旗鼓相当的.然而,最新的研究发现,碳酸盐溶解的快速动力学和硅酸盐岩流域中微量碳酸盐矿物的风化在控制该流域溶解无机碳(DIC)浓度和碳汇上的重要性,使得碳酸盐风化碳汇占整个岩石风化碳汇的94%,而硅酸盐风化仅占6%左右.另一方面,水生光合生物对DIC的利用及其形成的有机质(内源有机碳)的埋藏,使得碳酸盐风化碳汇在任何时间尺度气候变化的控制上可能都是重要的.此外,岩石风化碳汇研究的另一重要进展是发现了碳汇随全球变暖和土地利用变化显著增加,即形成了气候变化的负反馈机制.未来应通过岩石风化碳捕获和储存过程及其控制机理的进一步研究,揭示岩石风化碳汇过程及其气候和土地利用调控潜力,以服务于各国应对气候变化的国家政策制定.重点研究:①岩石风化碳汇过程及其物理、化学和生物控制机理;②硅酸盐岩流域中微量碳酸盐矿物的风化在控制流域DIC浓度及其碳汇上的重要性;③陆地水生光合生物利用DIC产生内源有机碳的效率;④气候变化和土地利用调控岩石风化碳汇的潜力.%It is widely accepted that the chemical weathering of silicate potentially controls long-term climate change by providing a feedback interaction with atmospheric CO2 drawdown by means of the precipitation of carbonate, while on a short time scale, the silicate-weathering-related carbon sink is well matched to the carbonate-weathering-related carbon sink. However, new findings show that owing to the rapid kinetics of carbonate dissolution and the importance of small amounts of carbonate minerals in controlling the dissolved inorganic C (DIC) of silicate watersheds

  1. 碳酸盐风化碳汇与森林碳汇的对比——碳汇研究思路和方法变革的必要性%Comparison of carbon sequestration capacity between carbonate weathering and forests: The necessity to change traditional ideas and methods of study of carbon sinks

    Institute of Scientific and Technical Information of China (English)

    刘再华; Wolfgang Dreybrodt

    2012-01-01

    目前,全球碳循环研究主要集中在海洋碳汇以及陆地土壤和植被碳汇,而对岩石风化碳汇仅考虑地质长时间尺度的硅酸盐风化作用,而认为碳酸盐风化在长时间尺度上对碳汇无贡献.然而,碳酸盐相对于硅酸盐有快得多的溶解速度,且对全球变化(特别是气候和CO,变化)的响应迅速,同时由于生物作用和人为活动的影响,使得碳酸盐风化碳汇的能力需要重新评价.最新的研究发现,由碳酸盐溶解、全球水循环及水生生物光合利用溶解无机碳共同作用,即水-岩-气-生相互作用形成的大气碳汇,远远大于之前只估计了河流输运的无机碳汇,其量级与森林碳汇量相当,因此有必要对传统的碳汇研究思路和方法进行某些变革,这有可能为解决所谓的全球“碳失汇”问题找到一条出路.%At present, researches on the modern global carbon cycle focuses mainly on carbon sinks caused by the oceans and the terrestrial soils and vegetations. In addition, chemical weathering of Ca-silicate rocks is considered to have the potential in controlling long-term climate change by providing feedback interactions with atmospheric CO2 drawdown by means of the precipitation of carbonate. In contrast, carbonate weathering itself has not been given equivalent attention although it is much more rapid than silicate weathering and more sensitive to global changes (especially climate and CO2 change). Further, biological and human activities also significantly influence carbonate weathering. Thus, the contribution of carbonate weathering to the atmospheric CO2 sink should be re-evaluated. Latest studies show that the carbon sink through the combined action of carbonate dissolution, the global water cycle, and photosynthetic uptake of dissolved inorganic carbon by aquatic organisms (i. e. , by carbonate weathering via the water-rock-gas-organism interaction) is far greater than previous estimates that have only considered

  2. 城市边缘区碳源碳汇用地空间扩张模式研究%Research on spatial expansion mode of land used for carbon source and sink at urban fringe areas

    Institute of Scientific and Technical Information of China (English)

    覃盟琳; 赵静; 黎航; 牙婧

    2014-01-01

    城市边缘区是城市碳源碳汇平衡的核心载体之一,是碳汇碳源用地转换的集中地。本文提出了碳源碳汇用地概念,总结了城市边缘区碳源碳汇用地空间结构扩张的六种基本模式,探讨了边缘区碳源碳汇用地空间结构变化规律。选取南宁市为研究对象,对南宁市遥感影像进行了监督分类,利用 ArcGIS 人机交互目视判读的方法,提取南宁市四个时间点边缘区的范围及其碳源碳汇用地构成。1990~2000年,南宁市边缘区碳源碳汇用地空间结构扩张模式以蔓延为主、指状为辅;2000~2006年,以指状型及独立型为主;2006~2013年,扩张模式为连片型。城市边缘区形态按“破碎-规则-发散-规则”方向变化,不同阶段具有的不同扩张模式对边缘区碳汇用地影响不同。边缘区碳汇用地主要以耕地与园地构成,保护耕地与园地成为增加碳汇用地的核心任务。城市边缘区的扩张方向受到城市未来发展方向的明显指引,其扩张方向体现了城市未来的发展方向。%Urban fringe areas is one of the core carriers for the balance of carbon source and sink in urban regions and the concentration areas for the conversion of land used for carbon source and sink. In order to obtain the change of spatial structure of the land used for carbon source and sink, and to guide low-carbon city development, expansion modes of spatial structure of the land used for carbon source and sink at urban fringe areas were studied. There are six expansion modes of spatial struc-tures of urban fringe areas. The remote sensing images of Nanning, capital of Guangxi province, are classified. Using ArcGIS, the range of fringe areas of Nanning is extracted by visual interpretation. From 1990 to 2000, expansion mode of spatial structure of the land used for carbon source and sink at Nanning fringe areas was rotary; from 2000 to 2006, the mode was finger and stand

  3. How Capillary Rafts Sink

    CERN Document Server

    Protiere, S; Aristoff, J; Stone, H

    2010-01-01

    We present a fluid dynamics video showing how capillary rafts sink. Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. Thanks to Archimedes principle we can easily predict whether an object sinks or floats. But what happens when several small particles are placed at an interface between two fluids. In this case surface tension also plays an important role. These particles self-assemble by capillarity and thus form what we call a "capillary raft". We show how such capillary rafts sink for varying sizes of particles and define how this parameter affects the sinking process.

  4. Copepods use chemical trails to find sinking marine snow aggregates

    DEFF Research Database (Denmark)

    Lombard, Fabien; Koski, Marja; Kiørboe, Thomas

    2013-01-01

    Copepods are major consumers of sinking marine particles and hence reduce the efficiency of the biological carbon pump. Their high abundance on marine snow suggests that they can detect sinking particles remotely. By means of laboratory observations, we show that the copepod Temora longicornis ca...

  5. Control factors and critical conditions between carbon sinking and sourcing of wetland ecosystem%湿地生态系统碳汇与碳源过程的控制因子和临界条件

    Institute of Scientific and Technical Information of China (English)

    孟伟庆; 吴绽蕾; 王中良

    2011-01-01

    Wetlands is the most important carbon sink as its special structure and characteristics. However the carbon sink functional of wetland has been weakened because of climate change and utilization, thus the trend that carbon sink conversion into carbon source is obvious. The control factors and critical conditions between carbon sinking and sourcing of wetland ecosystem were summarized from water content, plant types, soil thickness and microorganism which include substrate, Ph, temperature and redox conditions. The wetland oxygen condition is determined by the water level of wetland. There is a positive correlation between wetland water level and methane production, meanwhile it has negative correlation with carbon dioxide. The absorption and emission of carbon in wetland is affected by aerenchyma and root exudates of plant, but also the height and coverage of plant are important influence factors. The difference of microbial activity in different depths of soil layer, which result into the difference of absorption and emission carbon. The influence factors of active degree of methanogens include substrate, Ph, temperature and redox conditions. The production rate of CO2 and CH4 in shallow soil layer is higher than deep soil. Generally the increase of the substrate concentration will improve the methane generated rate and neutral or weak alkaline environment is the most suitable conditions for methanogens. Of course temperature also is the influence of methane generate and carbon dioxide. It has a negative correlation relationship between redox potential and methane generating. To summarize, because of the complexity of ecosystem struceture and the process of carbon emission and absorption, it can not give a clear conclusion that wetland is carbon sink or sourse in a word. But it is clear that control factors and critical conditions will transfer in certain environment conditions, and so some measures can be taken to improve the carbon sink functional of wetland

  6. Restoration and Assessment of Carbon Sink Potential for Aintertidal Oyster Reef in the Yangtze River Estuary, China%长江口牡蛎礁恢复及碳汇潜力评估

    Institute of Scientific and Technical Information of China (English)

    沈新强; 全为民; 袁骐

    2011-01-01

    牡蛎礁是温带河口和滨海区一种特殊的海洋生境,它具有生物生产、净化水体、提供鱼类生境、维持生物多样性和防止海岸侵蚀等重要功能,根据对长江口牡蛎礁恢复工程的跟踪监测结果,分析和评估该人工牡蛎礁恢复及碳汇潜力.研究结果表明,在2004-2010年期间,该人工牡蛎礁牡蛎种群的增长迅速,2005年牡蛎平均密度和生物量达到最高,以后各年牡蛎生长过程中存在“自疏”现象和死亡,总密度下降,但个体增长.牡蛎礁上大型底栖动物物种数、总密度和总生物量呈快速的增长趋势,2004年至2010年共出现大型底栖动物47种,至2010年8月其密度和生物量分别达到941 ind·m-2和44.51 g·m-2.该人工牡蛎礁具有强大的固碳能力,通过牡蛎的钙化过程,单位面积年固碳量为2.70 kg·m-2,年平均固定碳量达3.33×l04t,直接产生的年平均同碳效益达837万元,相当于营造l 1l0hm2热带森林.%With the adoption of Kyoto Protocol to the United Nation Framework Convention of Climate Change in 2005, carbon sink fishery becomes the hotspot among the fishery science and technology of China. Oyster reefs are very important marine habitats in temperate estuaries and coasts, providing large number of services and goods such as fishery production, water purification, fish habitat, maintenance of biodiversity, erosion control etc. So far, little information is available on the carbon sink potential of oyster reefs. The present study aimed to assess the restoration and carbon sink potential of a created intertidal oyster reef was in the Yangtze River estuary, China. The oyster( Crassostrea sp.) population rapidly increases with reef development, and its mean density and biomass reached the highest at approximately one year after restoration (in June 2005). Thereafter, the mean oyster density decreased with the increasing in the mean size of the oyster. The species richness, density and biomass of

  7. Heat sink analytical modelling

    OpenAIRE

    Guitart Corominas, Joaquim

    2010-01-01

    Electronics has leaded most technological advances of the past 60 years. There are technologies with domains particularly developed for electronics such as material science, electromagnetism, system dynamics and also heat transfer. The relation to heat transfer is because the heat generation of electronics devices. Commonly, these devices need additional cooling in order to avoid extreme temperatures inside it. Heat sinks allow this supplementary cooling, so they are omnipresent i...

  8. Carbonate deposits in marine fish intestines: contribution of marine fish cultures to carbon sink fisheries%鱼类肠道的碳酸盐结晶物:海水鱼类养殖在碳汇渔业中的地位和作用

    Institute of Scientific and Technical Information of China (English)

    吕为群; 陈阿琴; 刘慧

    2012-01-01

    鱼类是一个迄今尚未被认知的非常重要的微细碳酸盐沉积物的来源,对海洋固碳有着重要作用,这个发现直接影响到碳汇渔业的内涵.本研究介绍了海洋硬骨鱼类渗透压调节机制及鱼类肠道碳酸盐结晶形成与其肠细胞膜上物质转运之间的关系,着重阐述了鱼类肠道碳酸盐结晶的特征,并论述了通过对特定区域内鱼类生物量和碳酸盐排泄率数据的研究,估计出全球海洋鱼类每年可产生大约1.1亿t的碳酸钙,在海洋总碳酸盐岩泥中占14%以上.研究重点论述了海水鱼类固碳的独特优势潜力,同时,提出为了更好地确定海水鱼类养殖在碳汇渔业中的地位和作用,有必要对主要海水养殖鱼类肠道碳酸结晶物的形成量及其调控机制,碳收支动态模型进行研究,进而合理地估算和测定海水鱼类养殖的碳汇量.%A variety of marine ecosystems play an important role in the ocean biological carbon sink. More and more often, people are paying closer attention to impacts of marine fish on carbon cycle. Recent studies showed that marine fishes produce and excrete various forms of precipitated calcium carbonate with high magnesium content from their guts. Precipitation occurs as a by-product of the osmoregulatory requirement of teleosts to continuously drink Ca- and Mg-rich seawater. Using the Bahamian archipelago site specific fish biomass and carbonate excretion rate data, scientists estimated that marine fishes produce about l.lxlO9 kg CaCCVyear as mud-grade carbonate, and it is potential sediment constituent. Marine fishes contribute over 14% to total estimated global carbonate mud production. Therefore, marine fishes represent a hitherto unrecognized but significant source of fine-grained carbonate sediment, and affect coastal carbon sink capacity. This directly affects connotation of carbon sink fisheries. The carbon budget of marine fishes culture may influence carbon source and carbon

  9. Effect of Different Control Methods on Carbon Sink Function of Artificial Pinus kesiya var langbianensis Plantation%不同防治方法对思茅松人工林碳汇功能的影响

    Institute of Scientific and Technical Information of China (English)

    岳锋; 杨斌

    2011-01-01

    通过调查未经防治、经化学防治、物理机械防治和正常思茅松林分,测算了林木不同组分的生物量、含碳率和含碳量,并估算了4种思茅松林的BEF、生物量、碳储量、碳密度和碳汇功能.结果表明,景谷县思茅松人工林林木生物量、林木碳储量、土壤碳储量、林分总碳储量分别为1.51×10、7.83×10、1.42×10、2.28×10t,表现出巨大的碳汇;4种林分思茅松的BEF在0.94-1.00;思茅松不同组分生物量、碳储量的分配为干>根>枝>叶;林分有机碳的分配为土壤层>林木层>枯落物层>灌木层>草本层.松毛虫危害后,每株总生物量、每株碳储量、林分碳密度、土壤碳密度分别降低15.80 kg、8.10 kg、47.04 t/hm、32.66 t/hm,通过化学/物理机械防治后分别提高9.70 kg/6.90 kg、5.00 kg/3.62 kg、25.93 t/hm/19.50 t/hm、17.93 t/hm/13.09 t/hm.%Through surveying the standing forest of Pinus kesiya var langbianensis under different conditions, namely,without control, chemical control,physical and mechanical control as well as normal one,the biomass,carbon rate and carbon content of different components of P. kesiya varlangbianensis were determined, moreover,BEF,biomass,carbon storage,carbon density and carbon sink function of 4 kinds of forests were estimated. The result showed that the tree biomass,carbon storage of the tree,the soil and the forest in Jinggu County were 1.51 × 107 ,7.83 × l05 ,1.42 × 106 and 2.28 × 106 t,respeetively,these data showed carbon sink function of P. kesiya var langbianensis forest was strong; BEF of the 4 kinds of forests are from 0.410 2 to 1.250 O; the biomass and carbon storage of different components from high to low were:trunk > root >branch >leaf; the organic carbon storage of the forests from high to low were:soil horizon > woodyard > litter layer >bush layer > field stratum. The tree biomass and carbon storage,carbon density of the forest and the soil dropped 15.80 kg,8

  10. Enhanced ozone strongly reduces carbon sink strength of adult beech (Fagus sylvatica)--resume from the free-air fumigation study at Kranzberg Forest.

    Science.gov (United States)

    Matyssek, R; Wieser, G; Ceulemans, R; Rennenberg, H; Pretzsch, H; Haberer, K; Löw, M; Nunn, A J; Werner, H; Wipfler, P; Osswald, W; Nikolova, P; Hanke, D E; Kraigher, H; Tausz, M; Bahnweg, G; Kitao, M; Dieler, J; Sandermann, H; Herbinger, K; Grebenc, T; Blumenröther, M; Deckmyn, G; Grams, T E E; Heerdt, C; Leuchner, M; Fabian, P; Häberle, K-H

    2010-08-01

    Ground-level ozone (O(3)) has gained awareness as an agent of climate change. In this respect, key results are comprehended from a unique 8-year free-air O(3)-fumigation experiment, conducted on adult beech (Fagus sylvatica) at Kranzberg Forest (Germany). A novel canopy O(3) exposure methodology was employed that allowed whole-tree assessment in situ under twice-ambient O(3) levels. Elevated O(3) significantly weakened the C sink strength of the tree-soil system as evidenced by lowered photosynthesis and 44% reduction in whole-stem growth, but increased soil respiration. Associated effects in leaves and roots at the gene, cell and organ level varied from year to year, with drought being a crucial determinant of O(3) responsiveness. Regarding adult individuals of a late-successional tree species, empirical proof is provided first time in relation to recent modelling predictions that enhanced ground-level O(3) can substantially mitigate the C sequestration of forests in view of climate change.

  11. Floating Versus Sinking

    Science.gov (United States)

    Vella, Dominic

    2015-01-01

    Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.

  12. Preliminary Studies on Carbon Sinking Fisheries and Ecological Protection in Dongjiang Reservoir%东江水库碳汇渔业与生态保护的初步研究

    Institute of Scientific and Technical Information of China (English)

    邹忠义; 姚德华; 孙立仲; 何望; 欧燎原; 张政军

    2011-01-01

    2007年7月和10月对东江水库的水体初级生产力和水质进行了监测和评价,估算了天然渔业资源量及可移出碳量。研究表明,库区存在较丰富的外源性营养物质,主要来源于农业、生活废水及旅游业;10月水体水质优于7月,均属中营养水平;初级生产力平均为5.13g/(m2.d),与水体叶绿素、氨氮和总磷浓度呈较强的正相关;折算滤食性鱼产量为1541.9t/年,移出碳量为218.4t/年。2007-2010年进行鱼类增殖放流,获得天然滤食性渔获物最高达产量为900t/年,移出碳量127.5t/年。在制订东江水库渔业环境保护条例时,按初级生产力的大小,利用增殖放流等渔业去碳技术,适量投放滤食性鱼类,充分利用水体氮、磷,可实现东江水库碳汇渔业的可持续发展。%Estimating the catch of natural fisheries resources and the amount of possible remove carbon sinking behind under investigation on ambient of Dongjiang Reservoir,moreover,monitoring and evaluating the primary productivity and water quality.The results showed that abundant exogenous nutrient substances existed around the reservoir mainly from agriculture,domestic wastewater and tourism.The water quality in October was better than its in July,and also belong to middle nutritional level;the mean primary productivity was 5.13 g/(m2·d) and equal to the filter-feeding fish catch 1541.9 t/a that could remove probably total carbon 218.4 t/a.The primary productivity was in strong positive correlation with Chlorophyll-a,ammonia nitrogen and total phosphorus concentration.Fish was released from 2007 to 2010,and the annual highest yield of filter-feeding fish was 900 t which equal to 127.5 t carbon.N,P could be taken advantages of and reaching the purpose of sustainable development of carbon sinking fisheries through estimating the primary productivity and using the sinking carbon technology such as releasing filter-feeding fish for multiplication under making the

  13. Projections of multi-gas emissions and carbon sinks, and marginal abatement cost functions modelling for land-use related sources

    NARCIS (Netherlands)

    Graveland C; Bouwman AF; Vries B de; Eickhout B; Strengers BJ; MNV

    2003-01-01

    This report presents estimates of the costs of abatement of greenhouse gas emissions associated with landfills as a source of methane (CH4), sewage as a source of methane and nitrous oxide (CH4 and N2O, respectively) and carbon (C) sequestration in forest plantations. This is done in the form of so-

  14. Economics of fossil fuel substitution and wood product sinks when trees are planted to sequester carbon on agricultural lands in western Canada

    NARCIS (Netherlands)

    Kooten, van G.C.; Krcmar-Nozic, E.; Stennes, B.; Gorkom, van R.

    1999-01-01

    To meet its international commitment to reduce CO2 output by 7% from the 1990 level by 2012, Canada will rely to some extent on terrestrial carbon uptake, particularly afforestation of marginal agricultural land. The economics of afforestation is examined for northeastern British Columbia and all of

  15. The dynamic of organic carbon in South Cameroon. Fluxes in a tropical river system and a lake system as a varying sink on a glacial-interglacial time scale

    Energy Technology Data Exchange (ETDEWEB)

    Giresse, P. [Laboratoire de Sedimentologie et Geochimie Marines, URA CNRS 715, Universite de Perpignan, 66860 Perpignan (France); Maley, J. [Paleoenvironnements et Palynologie, ISEM/CNRS, UMR 5554, ORSTOM, UR 12, Universite de Montpellier II, 34095 Montpellier (France)

    1998-05-01

    a nearly homogenous carbon transfer during the last 20,000 years. Such results might be largely representative of tropical river system as the contrasting vegetal cover (savanna and forest) of the Sanaga basin reflected as well the majority of the intertropical ecosystem. Thus, an estimate of the Holocene transfer to the ocean up to four times the present carbon stored in soil of the surrounding continent implicates that the Holocene shelf was a significant organic carbon sink. Although the sources of the Sanaga River are located in a mountain region, a significant floodplain is not found downstream. This results in a significant altitudinal factor in the carbon fluxes to the ocean

  16. Electromagnetic Energy Sink

    CERN Document Server

    Valagiannopoulos, Constantinos A; Simovski, Constantin R; Tretyakov, Sergei A; Maslovski, Stanislav I

    2015-01-01

    The ideal black body fully absorbs all incident rays, that is, all propagating waves created by arbitrary sources. The known idealized realization of a black body is the perfectly matched layer (PML), widely used in numerical electromagnetics. However, ideal black bodies and PMLs do not interact with evanescent fields existing near any finite-size source, and the energy stored in these fields cannot be harvested. Here we introduce the concept of the ideal conjugate matched layer (CML), which fully absorbs energy of both propagating and evanescent fields of sources acting as an ideal sink for electromagnetic energy. Conjugate matched absorbers have exciting application potentials, as resonant attractors of electromagnetic energy into the absorber volume. We derive the conditions on the constitutive parameters of media which can serve as CML materials, numerically study the performance of planar and cylindrical CML and discuss possible realizations of such materials as metal-dielectric composites.

  17. The Time Changing Feature Analysis of Carbon Sinks in Songjiang District%松江区碳汇的时间变化特征分析

    Institute of Scientific and Technical Information of China (English)

    石忆邵; 韩广; 薛春晓

    2013-01-01

      随着全球人口激增及化石燃料的大量使用,全球环境和气候不断恶化。近年来,以致力于减少温室气体排放等的低碳经济、低碳生活等绿色理念不断提出。利用SPSS软件,采用主成分分析法,对松江区碳汇的时间变化特征及其驱动因素进行分析。研究结果表明,影响松江区碳汇时间变化驱动因素中,耕地为主驱动因子。从2002—2008年,松江区碳汇量显著减少,到2009年有所回升。%As the increasing of global population and the overuse of fossil fuels, the global environment and climate deteriorate constantly. In recent years, in order to reducing greenhouse gas emissions, low carbon economy, low carbon life, green concept put forward continuous-ly. This paper uses the software of SPSS, by principal component analysis method, analyses carbon time change characteristics and driving factors of the Songjiang District. Research results show that the main driving factor is in land. From 2002 to 2008, a significant reduction in the amount of carbon sequestration in Songjiang District, to 2009 rose.

  18. Simultaneous quantification of methane and carbon dioxide fluxes reveals that a shallow arctic methane seep is a net sink for greenhouse gases

    Science.gov (United States)

    Pohlman, J.; Greinert, J.; Ruppel, C. D.; Silyakova, A.; Vielstädte, L.; Magen, C.; Casso, M.; Bunz, S.; Mienert, J.

    2015-12-01

    Warming of high-latitude continental-margin oceans has the potential to release large quantities of carbon from gas hydrate and other sedimentary reservoirs. To assess how carbon mobilized from the seafloor might amplify global warming or alter ocean chemistry, a robust analysis of the concentrations and isotopic content of methane and carbon dioxide (CO2) in the water column and atmosphere is required. To this effect, a gas analysis system consisting of three cavity ring-down spectrometers was developed to obtain a real-time, three-dimensional characterization of the distribution and isotopic variability of methane and CO2 at a shallow (temperatures, elevated chlorophyll-fluorescence and 13C-enriched CO2 within the surface methane plume suggest that bubble-driven upwelling of cold, nutrient-rich water stimulated CO2 uptake by phytoplankton. The observation that a shallow methane seep has a net negative radiative forcing effect challenges the widely-held perception that methane seeps contribute to the global atmospheric greenhouse gas burden.

  19. Technical Note: A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter

    Directory of Open Access Journals (Sweden)

    R. Zhuravlev

    2011-10-01

    Full Text Available In this work we propose an approach to solving a source estimation problem based on representation of carbon dioxide surface emissions as a linear combination of a finite number of pre-computed empirical orthogonal functions (EOFs. We used National Institute for Environmental Studies (NIES transport model for computing response functions and Kalman filter for estimating carbon dioxide emissions. Our approach produces results similar to these of other models participating in the TransCom3 experiment.

    Using the EOFs we can estimate surface fluxes at higher spatial resolution, while keeping the dimensionality of the problem comparable with that in the regions approach. This also allows us to avoid potentially artificial sharp gradients in the fluxes in between pre-defined regions. EOF results generally match observations more closely given the same error structure as the traditional method.

    Additionally, the proposed approach does not require additional effort of defining independent self-contained emission regions.

  20. 森林碳汇价值实现对林地效益影响的路径及机理分析%Analysis of impacting path and mechanism of the realization of forest carbon sink value on forest benefits

    Institute of Scientific and Technical Information of China (English)

    徐秀英; 任腾腾

    2013-01-01

    Forest has a special position and important role in response to climate change, The international community to provide ways to realize the value of forest carbon sinks, Discussing the might affect of value of forest carbon sink on forest benefits has important theoretical and realistic significance. This article on the basis of the realization of forest carbon sink value affect path on the forest benefits, Forest carbon sink value realiza-tion in the situation of carbon trading were analyzed, The change of forest best rotation period, And the change of timber yield and carbon sequestration benefits, Finally, concluded that the change of forest land benefits.%森林在应对气候变化中具有特殊的地位和重要作用,国际社会努力为实现森林碳汇价值提供途径,探讨森林碳汇价值实现对林地效益可能产生的影响具有重要的理论和现实意义。本文在阐述森林碳汇价值实现对林地效益影响路径的基础上,分析了在森林碳汇价值实现的情境下,森林最佳轮伐期的变化情况,以及木材收益和碳汇收益的变化,最后得出林地效益的变化情况。

  1. Carbon Monitoring System Flux Estimation and Attribution: Impact of ACOS-GOSAT X(CO2) Sampling on the Inference of Terrestrial Biospheric Sources and Sinks

    Science.gov (United States)

    Liu, Junjie; Bowman, Kevin W.; Lee, Memong; Henze, David K.; Bousserez, Nicolas; Brix, Holger; Collatz, G. James; Menemenlis, Dimitris; Ott, Lesley; Pawson, Steven; Jones, Dylan; Nassar, Ray

    2014-01-01

    Using an Observing System Simulation Experiment (OSSE), we investigate the impact of JAXA Greenhouse gases Observing SATellite 'IBUKI' (GOSAT) sampling on the estimation of terrestrial biospheric flux with the NASA Carbon Monitoring System Flux (CMS-Flux) estimation and attribution strategy. The simulated observations in the OSSE use the actual column carbon dioxide (X(CO2)) b2.9 retrieval sensitivity and quality control for the year 2010 processed through the Atmospheric CO2 Observations from Space algorithm. CMS-Flux is a variational inversion system that uses the GEOS-Chem forward and adjoint model forced by a suite of observationally constrained fluxes from ocean, land and anthropogenic models. We investigate the impact of GOSAT sampling on flux estimation in two aspects: 1) random error uncertainty reduction and 2) the global and regional bias in posterior flux resulted from the spatiotemporally biased GOSAT sampling. Based on Monte Carlo calculations, we find that global average flux uncertainty reduction ranges from 25% in September to 60% in July. When aggregated to the 11 land regions designated by the phase 3 of the Atmospheric Tracer Transport Model Intercomparison Project, the annual mean uncertainty reduction ranges from 10% over North American boreal to 38% over South American temperate, which is driven by observational coverage and the magnitude of prior flux uncertainty. The uncertainty reduction over the South American tropical region is 30%, even with sparse observation coverage. We show that this reduction results from the large prior flux uncertainty and the impact of non-local observations. Given the assumed prior error statistics, the degree of freedom for signal is approx.1132 for 1-yr of the 74 055 GOSAT X(CO2) observations, which indicates that GOSAT provides approx.1132 independent pieces of information about surface fluxes. We quantify the impact of GOSAT's spatiotemporally sampling on the posterior flux, and find that a 0.7 gigatons of

  2. Sinking coastal cities

    Science.gov (United States)

    Erkens, G.; Bucx, T.; Dam, R.; de Lange, G.; Lambert, J.

    2015-11-01

    In many coastal and delta cities land subsidence now exceeds absolute sea level rise up to a factor of ten. A major cause for severe land subsidence is excessive groundwater extraction related to rapid urbanization and population growth. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will sink below sea level. Land subsidence increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. In addition, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs for (infra)structure. The total damage worldwide is estimated at billions of dollars annually. As subsidence is often spatially variable and can be caused by multiple processes, an assessment of subsidence in delta cities needs to answer questions such as: what are the main causes? What is the current subsidence rate and what are future scenarios (and interaction with other major environmental issues)? Where are the vulnerable areas? What are the impacts and risks? How can adverse impacts be mitigated or compensated for? Who is involved and responsible to act? In this study a quick-assessment of subsidence is performed on the following mega-cities: Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok. Results of these case studies will be presented and compared, and a (generic) approach how to deal with subsidence in current and future subsidence-prone areas is provided.

  3. Sinking rates of microplastics and potential implications of their alteration by physical, biological, and chemical factors.

    Science.gov (United States)

    Kowalski, Nicole; Reichardt, Aurelia M; Waniek, Joanna J

    2016-08-15

    To follow the pathways of microplastics in aquatic environments, profound knowledge about the behaviour of microplastics is necessary. Therefore, sinking experiments were conducted with diverse polymer particles using fluids with different salinity. Particles ranged from 0.3 and 3.6mm with sinking rates between 6 and 91×10(-3)ms(-1). The sinking velocity was not solely related to particle density, size and fluid density but also to the particles shape leading to considerable deviation from calculated theoretical values. Thus, experimental studies are indispensable to get basic knowledge about the sinking behaviour and to gain representative datasets for model approaches estimating the distribution of microplastics in aquatic systems. The sinking behaviour may be altered considerably by weathering and biofouling demanding further studies with aged and fouled plastic particles. Furthermore, assumptions are made about the influence of sinking fouled microplastics on the marine carbon pump by transferring organic carbon to deeper water depths.

  4. Sinking Coastal Cities

    Science.gov (United States)

    Erkens, G.; Stuurman, R.; De Lange, G.; Bucx, T.; Lambert, J.

    2014-12-01

    In many coastal cities land subsidence now exceeds absolute sea level rise up to a factor of ten. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will continue to sink, even below sea level. The ever increasing industrial and domestic demand for water in these cities results in excessive groundwater extraction, causing severe subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick sequences of soft soil. The impacts of subsidence are further exacerbated by climate-induced sea level rise. Land subsidence results in two types damage: foremost it increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. Secondly, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs of roads and transportation networks, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually. To survey the extent of groundwater associated subsidence, we conducted a quick-assessment of subsidence in a series of mega-cities (Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok). For each city research questions included: what are the main causes, how much is the current subsidence rate and what are predictions, where are the vulnerable areas, what are the impacts and risks, how can adverse impacts can be mitigated or compensated for, and what governmental bodies are involved and responsible to act? Using the assessment, this paper discusses subsidence modelling and measurement results from the selected cities. The focus is on the importance of delayed settlement after increases in hydraulic heads, the role of the subsurface composition for subsidence rates and best practice solutions for subsiding cities. For the latter, urban (ground)water management, adaptive flood risk management

  5. Biological Carbon Sinks: Transaction Costs and Governance

    NARCIS (Netherlands)

    Kooten, van G.C.

    2009-01-01

    Activities that remove CO2 from the atmosphere and store it in forest and agricultural ecosystems can generate CO2-offset credits that can thus substitute for CO2 emissions reduction. Are biological CO2-uptake activities competitive with CO2 offsets from reduced fossil fuel use? In this paper, it is

  6. Arctic Carbon Sinks: Present and Future.

    Science.gov (United States)

    1989-12-01

    between Isla Mujeres , Mexico, and Cabo San Antonio, Cuba (MouNARu and YAGER. 1977). Similarly 24.0Sv of northward transport were found above this...estimated (SHIR, 1973) by h = 0.46u*/f, (5) where f is once more the Coriolis parameter, yielding a second estimate of 14.3 m for h. This is similar to... MUJERES ISL2AVAA YUCATAN r S,oOo / MWES,. MEXICO 50 9 6 94 9 90 88 86 ,q 82 Fig. 1. Schematic map of the Gulf of Mexico showing areas for which

  7. On modeling weak sinks in MODPATH

    Science.gov (United States)

    Abrams, Daniel B.; Haitjema, Henk; Kauffman, Leon J.

    2012-01-01

    Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to pass. A physical strong sink can be modeled by either a strong sink cell or a weak sink cell, with the latter generally occurring in low resolution models. Likewise, a physical weak sink may also be represented by either type of sink cell. The representation of weak sinks in the particle tracing code MODPATH is more equivocal than in MODFLOW. With the appropriate parameterization of MODPATH, particle traces and their associated travel times to weak sink streams can be modeled with adequate accuracy, even in single layer models. Weak sink well cells, on the other hand, require special measures as proposed in the literature to generate correct particle traces and individual travel times and hence capture zones. We found that the transit time distributions for well water generally do not require special measures provided aquifer properties are locally homogeneous and the well draws water from the entire aquifer depth, an important observation for determining the response of a well to non-point contaminant inputs.

  8. ECONOMIC EVALUATION OF CO2 STORAGE AND SINK ENHANCEMENT OPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Bert Bock; Richard Rhudy; Howard Herzog; Michael Klett; John Davison; Danial G. De La Torre Ugarte; Dale Simbeck

    2003-02-01

    This project developed life-cycle costs for the major technologies and practices under development for CO{sub 2} storage and sink enhancement. The technologies evaluated included options for storing captured CO{sub 2} in active oil reservoirs, depleted oil and gas reservoirs, deep aquifers, coal beds, and oceans, as well as the enhancement of carbon sequestration in forests and croplands. The capture costs for a nominal 500 MW{sub e} integrated gasification combined cycle plant from an earlier study were combined with the storage costs from this study to allow comparison among capture and storage approaches as well as sink enhancements.

  9. Heat Sink Design and Optimization

    Science.gov (United States)

    2015-12-01

    Natural convection Radiation Design Modeling Optimization 16. SECURITY CLASSIFICATION OF: 17...Hs = 3.94 in.  Width Ws = 5.42 in.  Fins  Height Hf = 0.98 in.  Length...different fin thicknesses (tf) The next parameter considered was fin height, Hf . Smaller height has a negative influence on overall heat sink

  10. Divergence in sink contributions to population persistence.

    Science.gov (United States)

    Heinrichs, Julie A; Lawler, Joshua J; Schumaker, Nathan H; Wilsey, Chad B; Bender, Darren J

    2015-12-01

    Population sinks present unique conservation challenges. The loss of individuals in sinks can compromise persistence; but conversely, sinks can improve viability by improving connectivity and facilitating the recolonization of vacant sources. To assess the contribution of sinks to regional population persistence of declining populations, we simulated source-sink dynamics for 3 very different endangered species: Black-capped Vireos (Vireo atricapilla) at Fort Hood, Texas, Ord's kangaroo rats (Dipodomys ordii) in Alberta, and Northern Spotted Owls (Strix occidentalis caurina) in the northwestern United States. We used empirical data from these case studies to parameterize spatially explicit individual-based models. We then used the models to quantify population abundance and persistence with and without long-term sinks. The contributions of sink habitats varied widely. Sinks were detrimental, particularly when they functioned as strong sinks with few emigrants in declining populations (e.g., Alberta's Ord's kangaroo rat) and benign in robust populations (e.g., Black-capped Vireos) when Brown-headed Cowbird (Molothrus ater) parasitism was controlled. Sinks, including ecological traps, were also crucial in delaying declines when there were few sources (e.g., in Black-capped Vireo populations with no Cowbird control). Sink contributions were also nuanced. For example, sinks that supported large, variable populations were subject to greater extinction risk (e.g., Northern Spotted Owls). In each of our case studies, new context-dependent sinks emerged, underscoring the dynamic nature of sources and sinks and the need for frequent re-assessment. Our results imply that management actions based on assumptions that sink habitats are generally harmful or helpful risk undermining conservation efforts for declining populations.

  11. A possible important CO2 sink by the global water cycle

    Institute of Scientific and Technical Information of China (English)

    LIU ZaiHua; Wolfgang DREYBRODT; WANG HaiJing

    2008-01-01

    The locations, magnitudes, variations and mechanisms responsible for the global CO2 sink are uncer-tain and under debate. Here, we show, based on theoretical calculations and evidences from field monitoring results, that there is a possible important CO2 sink (as DIC-dissolved inorganic carbon) by the global water cycle. The sink constitutes up to 0.8013 Pg C/a (or 10.1% of the total anthropogenic CO2 emission, or 28.6% of the missing CO2 sink), and is formed by the CO2 absorption of water and subsequent enhanced consumption by carbonate dissolution and aquatic plant photosynthesis. Of the sink, 0.5188 Pg C/a goes to sea via precipitation over sea (0.2748 Pg C/a) and continental rivers (0.244 Pg C/a), 0.158 Pg C/a is released to the atmosphere again, and 0.1245 Pg C/a is stored in the continental aquatic ecosystem. Therefore, the net sink could be 0.6433 Pg C/a. This sink may increase with the global-warming-intensified global water cycle, the increase in CO2 and carbonate dust in atmosphere, and reforestation/afforestation, the latter increasing soil CO2, and thus the concentration of the DIC in water.

  12. Analysis on Characteristics of Carbon Source/Sink in Farmland Ecosystem in Chongqing Based on ArcGIS%基于 A rcGIS 的重庆市农田生态系统碳源/汇特征研究

    Institute of Scientific and Technical Information of China (English)

    罗海秀; 王龙昌

    2015-01-01

    Based on the statistical data of crop yields ,cropland areas and agricultural inputs from 1997 to 2011 in Chongqing ,the amounts of carbon absorption ,carbon emission and the intensity of carbon sink have been calculated ,and by means of ArcGIS ,the spatial_temporal variations has been analyzed .The conclusions are as following :the total amounts of carbon absorption show a stabilized trend from 1997 to 2011 ;the carbon absorption ratios of food crops declined ,and the carbon absorption ratios of economic crops and fruits_vegetables crops show remarkable increasing ;the total amounts of carbon emissions show a gradual upward trend ,and the agrochemical inputs is the main source .From space ,the amounts and in_tensity of carbon absorption , carbon emissions , carbon sink in the three major economic regions of Chongqing in 2011 show :One_hour Urban Economy Circle> Northeast of Chongqing Area> Southeast of Chongqing Area .Based on these conclusions ,suggestions and recommendations were provided .%以1997-2011年重庆市农作物产量、耕地面积及农业投入等相关统计数据为依据,对重庆市农田生态系统碳吸收量、碳排放量和碳汇强度进行了测算,以ArcGIS为技术手段进行碳源/汇空间特征分析。结果表明:1997-2011年重庆农田生态系统碳吸收总量总体处于稳定态势,粮食作物碳吸收比例下降,经济作物和果蔬作物碳吸收比例明显上升;碳排放总量呈逐步上升趋势,农用化学品投入是其主要排放源。从空间上看,2011年重庆市三大经济区域农田生态系统碳吸收、碳排放、碳汇的总量和强度从大到小依次为一小时经济圈、渝东北地区、渝东南地区。

  13. Sink-to-Sink Coordination Framework Using RPL: Routing Protocol for Low Power and Lossy Networks

    Directory of Open Access Journals (Sweden)

    Meer M. Khan

    2016-01-01

    Full Text Available RPL (Routing Protocol for low power and Lossy networks is recommended by Internet Engineering Task Force (IETF for IPv6-based LLNs (Low Power and Lossy Networks. RPL uses a proactive routing approach and each node always maintains an active path to the sink node. Sink-to-sink coordination defines syntax and semantics for the exchange of any network defined parameters among sink nodes like network size, traffic load, mobility of a sink, and so forth. The coordination allows sink to learn about the network condition of neighboring sinks. As a result, sinks can make coordinated decision to increase/decrease their network size for optimizing over all network performance in terms of load sharing, increasing network lifetime, and lowering end-to-end latency of communication. Currently, RPL does not provide any coordination framework that can define message exchange between different sink nodes for enhancing the network performance. In this paper, a sink-to-sink coordination framework is proposed which utilizes the periodic route maintenance messages issued by RPL to exchange network status observed at a sink with its neighboring sinks. The proposed framework distributes network load among sink nodes for achieving higher throughputs and longer network’s life time.

  14. Modeling Atmospheric CO2 Processes to Constrain the Missing Sink

    Science.gov (United States)

    Kawa, S. R.; Denning, A. S.; Erickson, D. J.; Collatz, J. C.; Pawson, S.

    2005-01-01

    We report on a NASA supported modeling effort to reduce uncertainty in carbon cycle processes that create the so-called missing sink of atmospheric CO2. Our overall objective is to improve characterization of CO2 source/sink processes globally with improved formulations for atmospheric transport, terrestrial uptake and release, biomass and fossil fuel burning, and observational data analysis. The motivation for this study follows from the perspective that progress in determining CO2 sources and sinks beyond the current state of the art will rely on utilization of more extensive and intensive CO2 and related observations including those from satellite remote sensing. The major components of this effort are: 1) Continued development of the chemistry and transport model using analyzed meteorological fields from the Goddard Global Modeling and Assimilation Office, with comparison to real time data in both forward and inverse modes; 2) An advanced biosphere model, constrained by remote sensing data, coupled to the global transport model to produce distributions of CO2 fluxes and concentrations that are consistent with actual meteorological variability; 3) Improved remote sensing estimates for biomass burning emission fluxes to better characterize interannual variability in the atmospheric CO2 budget and to better constrain the land use change source; 4) Evaluating the impact of temporally resolved fossil fuel emission distributions on atmospheric CO2 gradients and variability. 5) Testing the impact of existing and planned remote sensing data sources (e.g., AIRS, MODIS, OCO) on inference of CO2 sources and sinks, and use the model to help establish measurement requirements for future remote sensing instruments. The results will help to prepare for the use of OCO and other satellite data in a multi-disciplinary carbon data assimilation system for analysis and prediction of carbon cycle changes and carbodclimate interactions.

  15. Derivation of sink strengths in bounded media

    Energy Technology Data Exchange (ETDEWEB)

    Brailsford, A.D. (Ford Motor Co., Dearborn, MI (USA). Engineering and Research Staff)

    1981-11-01

    Several reasons for the need to extend the rate theory of point defect recovery processes to bounded media are cited. This paper is concerned with the essential first step, the derivation of the strength of sinks near a free surface. The Effective Medium method is used. Sink strengths so derived are shown to be formally the same as those found in an unbounded system. Image effects associated with the surface are proved to be small when the sink is located more than a few sink radii from the surface.

  16. Comparison of Karst Process-Related Carbon Sink Intensity Between an Alpine Glaciated and Snow Covered Karst Water System and Humid Subtropical Karst Water System%高寒冰雪覆盖型和湿润亚热带型岩溶水系统碳汇强度对比

    Institute of Scientific and Technical Information of China (English)

    曾成; 赵敏; 杨睿; 刘再华; Vivian Gremaud; Nico Goldscheider

    2011-01-01

    以岩性相近但气候和土地利用迥异的两个具有高分辨率水文水化学自动监测数据的岩溶水系统-湿润亚热带以土质坡地为主的岩溶水系统(贵州普定后寨岩溶水系统)和高寒冰雪覆盖下以石质坡地为主的岩溶水系统(瑞士阿尔卑斯山区的Tsanfleuron冰川岩溶水系统)作为研究对象,进行岩溶作用碳汇强度对比研究.结果发现,后寨岩溶水系统的[HCO3-]年均值为222mg/L,而Tsanfleuron冰川岩溶水系统的[HCO3-]年均值仅为131mg/L,表明湿润亚热带岩溶水系统具有较高的[HCO3-]特征.然而,湿润亚热带岩溶水系统的碳汇强度(60.82t/(km2·a))与Tsanfleuron冰川岩溶水系统的碳汇强度(59.06t/km2·a))相当.冰川岩溶水系统同样具有较高岩溶作用碳汇强度的原因主要是在全球变暖的背景下,冰川退缩加剧,冰川固体水库水量释放增多,致使冰川岩溶水系统径流量显著增加效应超出因稀释作用而产生的[HCO3-]降低效应,进而使得山岳冰川岩溶水系统的碳汇强度增大.这也暗示着随着某些冰川融化,径流量逐渐减小将使岩溶作用碳汇强度降低.%A comparative study on karst process-related carbon sink intensity between the two karst water systems with similar lithology but different climate and land use scenarios and with high resolution hydrological and hydrochemical automatic monitoring data is presented to show the significance ofnmoffin determining the carbonate weathering carbon sink intensity. The two systems are Houzhai karst water system with high ratio of soil cover in catchment area (Puding County, Guizhou Province, Southwest China), and Tsanfleuron glaciated and snow covered rocky karst water system in Alps, Switzerland. The results show that the annual mean concentration of HCO3- of Houzhai karst water systems in their discharge areas is 222 mg/L, while that of Tsanfleuron karst water system is only 131 mg/L. This indicates that the karst water

  17. The Economic Benefits Analysis of the Carbon Sink Effect on the Reforestation Project in the Centre Guizhou Province%黔中喀斯特地区退耕还林项目的碳汇经济效益分析

    Institute of Scientific and Technical Information of China (English)

    焦树林; 艾其帅

    2011-01-01

    The increasing unceasingly of the global atmospheric CO2 concentration will lead to global climate change caused by the greenhouse effect of the atmospheric CO2, which sharply challenges the sustainable development of the human society. Atmospheric carbon reduction has become the consensus of human society. As China's carbon sinks market development and gradually improvement, returning farmland to forest carbon sinks in the economic value of benefits will become increasingly prominent. In this study, the program of the returning farmland to forests were surveyed in the Hongfenghu Basin Drainage area,mainly tree species in the region of Lin Chinese fir, cedar, peach, plum, apricot, camptothecin, such as seven kinds of bungei Carbon trees a preliminary estimate of net reserves during the time from 2000 to 2006. There would be 1.05x104kg forest carbon storage in all of the Hongfenghu Basin Drainage during the next 5 years from 2000 to 2006. The carbon storage and carbon density of the forest, especially the young growth forest have an increasing trend with the plants growing time lengthened, and the young growth will play an increasing potential for the carbon sequestration. The volumes of the forest carbon sequestration were calculated through the trees on the forecast volume, the study in the seven kinds of trees, the fir is to examine the regional carbon sink function of strong trees, Japanese cedar, followed by fruit trees of the carbon sink function of the weakest. There would be 2.21 × 104kg forest carbon storage in all of the Hongfenghu Basin Drainage during the next 10 years, and would generate the economic benefits of 7.17×106 yuan according to the analysis on the economic benefits of the carbon sequestration by 305 yuan per a ton in prices.%由大气CO2浓度不断增加引起的温室效应而导致全球气候变化对人类社会的可持续发展构成了巨大挑战,大气碳的减排增汇已经成为人类社会的共识.随着我国碳汇交易市

  18. Not all calcite ballast is created equal: differing effects of foraminiferan and coccolith calcite on the formation and sinking of aggregates

    Directory of Open Access Journals (Sweden)

    K. Schmidt

    2013-09-01

    Full Text Available Correlation between particulate organic carbon (POC and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foraminferan-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the roller tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast- different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.

  19. Research on countermeasures of cross-strait agricultural carbon sequestration transaction: A case of the planning of the trading center of Fujian and Taiwan agricultural carbon sinks%海峡两岸碳汇农业研究与交易平台建设的思考与对策——以闽台农业碳汇交易中心规划研究为例

    Institute of Scientific and Technical Information of China (English)

    翁伯琦; 王义祥; 黄毅斌

    2011-01-01

    在全球气候变化的大背景下,发展低碳经济已经成为全球性共识;同时作为发展低碳经济前沿领域的碳交易市场也得以迅速发展.本文简要综述了我国农业碳汇交易研究和碳交易市场发展的现状及其存在的问题,分析了在福建建立海峡两岸农业碳汇交易平台的政策机遇和区域优势,提出了构建闽台农业碳汇交易中心的规划设想,并结合规划设想提出了要加强碳汇农业理论与节能减排技术、低碳农业发展规划与综合评估体系、农业碳汇交易机制、监测及其认证体系等农业碳汇研究的方向与建议.%Low-carbon economy has become a global consensus in the background of global climate change. Meanwhile, the carbon trading market as the frontier of low-carbon economy, is developing rapidly. This paper reviews progress and problems in the research of agricultural carbon sequestration and development of carbon trading market. The policy opportunities and regional advantages of Fujian province are analyzed to establish cross-strait agricultural carbon trading platform. Thus, the construction of the trading center of Fujian and Taiwan agricultural carbon sinks is proposed. Some research directions in agricultural Carbon Sequestration are putted forward, such as carbon sequestration and energy saving technology of agriculture, planning, monitoring and evaluation system of Iow-carbon agricultural and the mechanisms and certification system agricultural carbon sequestration trading,and so on.

  20. A molecular-genetic approach to studying source-sink interactions in Arabidopsis thaliana. Final report, April 1, 1995--March 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, S.I.

    1998-11-01

    The ultimate goal of this research is to elucidate the molecular mechanisms by which the complex interactions between sources and sinks of fixed carbon are controlled in plants. As soluble sugar levels have been shown to play a vital role in a variety of source-sink interactions, a key aspect of the authors research is to determine the role of sugar-regulated gene expression in mediating source-sink interactions. In addition, as a critical aspect of source-sink interactions is the channeling of fixed carbon into different storage forms, they have pursued the findings that fumaric acid represents a significant form of storage carbon in Arabidopsis thaliana and other plant species. In the future, a better understanding of the mechanisms by which interactions between sources and sinks of fixed carbon are coordinated will be a pre-requisite to developing more rationale approaches to improving harvest indices in crop species.

  1. Geographical, seasonal, and depth variation in sinking particle speeds in the North Atlantic

    Science.gov (United States)

    Villa-Alfageme, M.; Soto, F. C.; Ceballos, E.; Giering, S. L. C.; Le Moigne, F. A. C.; Henson, S.; Mas, J. L.; Sanders, R. J.

    2016-08-01

    Particle sinking velocity is considered to be a controlling factor for carbon transport to the deep sea and thus carbon sequestration in the oceans. The velocities of the material exported to depth are considered to be high in high-latitude productive systems and low in oligotrophic distributions. We use a recently developed method based on the measurement of the radioactive pair 210Po-210Pb to calculate particle sinking velocities in the temperate and oligotrophic North Atlantic during different bloom stages. Our estimates of average sinking velocities (ASVs) show that slowly sinking particles (<100 m d-1) contribute significantly to carbon flux at all the locations except in the temperate regions during the bloom. ASVs appear to vary strongly with season, which we propose is caused by changes in the epipelagic community structure. Our results are the first field data to confirm the long-standing theory that particle sinking velocities increase with depth, with increases of up to 90% between 50 and 150 m depth.

  2. Topology Optimization of Thermal Heat Sinks

    DEFF Research Database (Denmark)

    Klaas Haertel, Jan Hendrik; Engelbrecht, Kurt; Lazarov, Boyan Stefanov

    2015-01-01

    in COMSOL Multiphysics. The optimization objective is to minimize the heat sink’s temperature for a prescribed pressure drop and fixed heat generation. To conduct the optimization, COMSOL’s Optimization Module with GCMMA as the optimization method is used. The implementation of this topology optimization...... approach in COMSOL Multiphysics is described in this paper and results for optimized two-dimensional heat sinks are presented. Furthermore, parameter studies regarding the effect of the prescribed pressure drop of the system on Reynolds number and realized heat sink temperature are presented and discussed.......In this paper, topology optimization is applied to optimize the cooling performance of thermal heat sinks. The coupled two-dimensional thermofluid model of a heat sink cooled with forced convection and a density-based topology optimization including density filtering and projection are implemented...

  3. The science of greenhouse gases: uncertainties in sources and sinks, and implications for verification

    Energy Technology Data Exchange (ETDEWEB)

    Meijer, H.A.J. [Groningen University, Groningen (Netherlands). Centrum voor IsotopenOnderzoek

    2001-07-01

    Our present knowledge about the carbon cycle, governing the sources and sinks of the most important anthropogenically influenced greenhouse gas CO{sub 2}, is still far from satisfactory in the quantitative sense. This statement holds on all scales, from global to local. Therefore, long-term atmospheric measurements, on many locations, are absolutely needed, both to improve our quantitative knowledge of the carbon cycle and to create a firm verification basis for mitigation measures. Yet, it is an illusion to think that source/sink characterisation by these atmospheric measurements will go to the detail that Kyoto Protocol actions can be surveyed and verified on a national level in the coming years (if ever). Therefore, a combination of validation (on project basis) and verification (on a continental scale) is proposed. Mitigation measures through mere sink enhancement (afforestation) are at best a temporary solution. Therefore, not much (political) effort should be invested into this option. 36 refs., 9 figs.

  4. 中国东北地区20世纪末土地利用变化的土壤碳源汇效应%Soil carbon source/sink caused by landuse change in the last decades of the last century in Northeast China

    Institute of Scientific and Technical Information of China (English)

    夏学齐; 杨忠芳; 余涛; 侯青叶; 白荣杰; 崔玉军

    2011-01-01

    土地利用变化是土壤有机碳库变化的重要原因之一。文中选择中国东北地区,利用多目标区域地球化学调查数据,结合20世纪80年代和2000年土地利用数据,分析了不同土地利用方式下土壤有机碳密度分布特征,以及由于土地利用方式变化形成的土壤碳源汇效应。结果发现:(1)不同土地利用下土壤表层有机碳密度(SOCD)差异较大,沼泽地、有林地等是SOCD相对较高的土地利用类型,而沙地、盐碱地、低覆盖草地等土地利用方式下SOCD较低;(2)按照土地利用方式的构成推算,研究区表层(O~20cm)土壤有机碳储量为482.1×10^10kg,其主要储库为有林地和旱地,分别占土壤总有机碳储量的43.8%和21.4%;(3)东北地区由于土地利用方式变化造成的土壤总碳源值为5.73×10^10kg,总碳汇值为3.56×10^10kg,因此研究区总体上表现为2.17×10^10kg(21.7Tg)的碳源;(4)研究区起到土壤碳汇作用的典型土地利用转化方式有旱地到水田的转化、其他林地和疏林地到有林地的转化等;起到土壤碳源作用的典型土地利用转化方式为有林地到旱地的转化、高覆盖草地到旱地的转化、沼泽到水田和旱地等耕地的转化等。%Landuse change is one of the most important factors that influence the variation of the soil organic carbon pool. Soil organic carbon density (SOCD) under different landuses and the effect of soil carbon source/ sink caused by landuse change in Northeast China was investigated using soil data from the regional multi-purpose geochemical survey and landuse data of two temporal points: 1980s and the year of 2000. The following conclusions were drawn: (1) SOCD varied significantly with different landuses; bog and thick forest have the highest SOCD, and sand land, saline land and thin grass land are the landuse types with low SOCD; (2) the

  5. Important aspects of sinks for linking emission trading systems

    Energy Technology Data Exchange (ETDEWEB)

    Hirsbrunner, Simon; Taenzler, Dennis; Reuster, Lena [Adelphi Research gGmbH, Berlin (Germany)

    2011-06-15

    The discussion on how to design policy instruments to reduce emissions and enhance removals from land use, land use change, and forestry is likely to be a key feature of a future global climate protection framework and will also influence the design of an emerging global carbon market. By analyzing different ETSs it turns out that very specific provisions are in place to deal with carbon sinks. Different instruments, eligible activities and standards reflect the prevailing emissions profile and cultural preferences of a geographic area. The inclusion of forestry in a cap, for instance, makes provisions on additionality and non-permanence obsolete, but increases the relevance of other issues such as accounting and enforcement. (orig.)

  6. The dominant role of semi-arid ecosystems in the trend and variability of the land CO2 sink

    DEFF Research Database (Denmark)

    Ahlström, Anders; Raupach, Michael R.; Schurgers, Guy;

    2015-01-01

    The growth rate of atmospheric carbon dioxide (CO2) concentrations since industrialization is characterized by large interannual variability, mostly resulting from variability in CO2 uptake by terrestrial ecosystems (typically termed carbon sink). However, the contributions of regional ecosystems...... regions. Whereas the mean sink is dominated by highly productive lands (mainly tropical forests), the trend and interannual variability of the sink are dominated by semi-arid ecosystems whose carbon balance is strongly associated with circulation-driven variations in both precipitation and temperature....

  7. Influence of plankton community structure on the sinking velocity of marine aggregates

    Science.gov (United States)

    Bach, L. T.; Boxhammer, T.; Larsen, A.; Hildebrandt, N.; Schulz, K. G.; Riebesell, U.

    2016-08-01

    About 50 Gt of carbon is fixed photosynthetically by surface ocean phytoplankton communities every year. Part of this organic matter is reprocessed within the plankton community to form aggregates which eventually sink and export carbon into the deep ocean. The fraction of organic matter leaving the surface ocean is partly dependent on aggregate sinking velocity which accelerates with increasing aggregate size and density, where the latter is controlled by ballast load and aggregate porosity. In May 2011, we moored nine 25 m deep mesocosms in a Norwegian fjord to assess on a daily basis how plankton community structure affects material properties and sinking velocities of aggregates (Ø 80-400 µm) collected in the mesocosms' sediment traps. We noted that sinking velocity was not necessarily accelerated by opal ballast during diatom blooms, which could be due to relatively high porosity of these rather fresh aggregates. Furthermore, estimated aggregate porosity (Pestimated) decreased as the picoautotroph (0.2-2 µm) fraction of the phytoplankton biomass increased. Thus, picoautotroph-dominated communities may be indicative for food webs promoting a high degree of aggregate repackaging with potential for accelerated sinking. Blooms of the coccolithophore Emiliania huxleyi revealed that cell concentrations of 1500 cells/mL accelerate sinking by about 35-40%, which we estimate (by one-dimensional modeling) to elevate organic matter transfer efficiency through the mesopelagic from 14 to 24%. Our results indicate that sinking velocities are influenced by the complex interplay between the availability of ballast minerals and aggregate packaging; both of which are controlled by plankton community structure.

  8. Carbon sink potential of multistrata agroforestry systems at Atlantic Rain Forest Potencial de sistemas agroflorestais multiestrata para sequestro de carbono em áreas de ocorrência de Floresta Atlântica

    Directory of Open Access Journals (Sweden)

    Luís Cláudio Maranhão Froufe

    2011-06-01

    Full Text Available

    Carbon storage of agroforestry systems, regenerated areas, conventional agriculture and pasture was evaluated at Alto Ribeira Valley region, São Paulo State, Brazil, in different compartments of Land-use systems (LUS. In soil, classified as Entisols and Inceptisols, we found similarities among all LUS, dued to their low contents of organic carbon, and similar values of bulk density. The total carbon stocked on land-use systems, greater amounts were determined on regenerated areas (115.78 Mg ha-1, followed by agroforestry systems (75.38 Mg ha-1, agriculture (47.07 Mg ha-1, and pasture (36.01 Mg ha-1. Despite their conservative characteristic, the silvicultural practices of multistrata agroforestry systems have to be improved for forest production and carbon sequestration.

    doi: 10.4336/2011.pfb.31.66.143

    Foi avaliado o estoque de carbono no solo, serapilheira, biomassa arbórea e biomassa herbácea de SAFs multiestratos, em comparação a capoeiras em diferentes estágios de regeneração, sistemas agrícolas convencionais e pastagem, todos na região do Alto Vale do Ribeira, SP. Nos Neossolos e Cambissolos, com baixos teores de carbono orgânico e similaridade dos valores de densidade aparente, as capoeiras contribuíram com 115,78 Mg ha-1 de carbono total estocado, seguidas dos SAFs (75,37 Mg ha-1, das áreas agrícolas (47,07 Mg ha-1 e das pastagens (36,01 Mg ha-1. Apesar do grande potencial de sequestro de carbono dos SAFs, há necessidade de melhoria em suas práticas silviculturais.

    doi: 10.4336/2011.pfb.31.66.143

  9. Carbon stocks and sinks in forestry for the unitéd Kingdom greenhouse gas inventory. COST E21 Workshop. Contribution of forests and forestry to mitigate greenhouse effects. Joensuu (Finland). 28-30 Sep 2000

    OpenAIRE

    Milne R.; Hargreaves K.; Murray M.

    2000-01-01

    Afforestation in the UK has been significant and continuing since 1920 (up to 30,000 ha per year). Planting data is used to drive a dynamic process-based carbon accounting model (C-Flow) to estimate removals of atmospheric CO2 to these forests. It is assumed that the afforestation can be represented by the characteristics of Sitka spruce for conifers and beech for broadleaves. The present area of forest considered for these estimates is 1.6 millions ha. In 1990 the uptake to trees, litter, so...

  10. Late-stage sinking of plutons

    Science.gov (United States)

    Glazner, A.F.; Miller, D.M.

    1997-01-01

    Many granodiorite to diorite plutons in the Great Basin of western North America are surrounded by rim monoclines or anticlines that suggest relative downward movement of the plutons while wall rocks were hot and ductile. We propose that such plutons rise to a level of approximately neutral buoyancy and then founder as their densities increase ??? 40% during crystallization. Late-stage sinking of intermediate to mafic plutons should be common when wall rocks are rich in weak, low-density minerals such as quartz and calcite. Structures related to sinking will overprint those related to initial pluton emplacement and may be mistaken for regional tectonic structures.

  11. Changes of the oceanic CO2 sink in the Eastern Indian sector of the Southern Ocean

    OpenAIRE

    Brévière, Emily; Metzl, Nicolas; Poisson, Alain; Tilbrook, Bronte

    2011-01-01

    Changes in the carbon dioxide fugacity (fCO2) and air–sea CO2 flux observed in the Southern Ocean, south of Tasmania were analysed and compared for two different years: 1996/1997 and 2002/2003. The CO2 flux showed large and contrasting interannual changes in the permanent open ocean zone (POOZ, 53–61°S) between the 2 yr where the oceanic CO2 sink increased from about −0.3 mmol m−2 d−1 in February 1997 to −20.6 mmol m−2 d−1 in February 2003. The strong sink in February 2003 was associated with...

  12. Nitrogen sink in a small forested watershed of subtropical China

    Institute of Scientific and Technical Information of China (English)

    Laiming Huang; Jinling Yang; Ganlin Zhang

    2011-01-01

    Global nitrogen (N) emission and deposition have been increased rapidly due to massive mobilization of N which may have longreaching impacts on ecosystems. Many agricultural and forest ecosystems have been identified as secondary N sources. In the present study, the input-output budget of inorganic N in a small forested watershed of subtropical China was investigated. Inorganic N wet deposition and discharge by stream water were monitored from March, 2007 to February, 2009. The concentrations and fluxes of inorganic N in wet precipitation and stream water and net retention of N were calculated. Global N input by dry deposition and biological fixation and N output by denitrification for forested watersheds elsewhere were reported as references to evaluate whether the studied forested watershed is a source or a sink for N. The results show that the inorganic N output by the stream water is mainly caused by NO3--N even though the input is dominated by NH4+-N. The mean flux of inorganic N input by wet precipitation and output by stream water is 1.672 and 0.537 g N/(m2·yr), respectively, which indicates that most of inorganic N input is retained in the forested watershed. Net retention of inorganic N reaches 1.135 g N/(m2·yr) considering wet precipitation as the main input and stream water as the main output. If N input by dry deposition and biological fixation and output by denitrification are taken into account, this subtropical forested watershed currently acts as a considerable sink for N, with a net sink ranging from 1.309 to 1.913 g N/(m2·yr)which may enhance carbon sequestration of the terrestrial ecosystem.

  13. Nitrogen sink in a small forested watershed of subtropical China.

    Science.gov (United States)

    Huang, Laiming; Yang, Jinling; Zhang, Ganlin

    2011-01-01

    Global nitrogen (N) emission and deposition have been increased rapidly due to massive mobilization of N which may have long-reaching impacts on ecosystems. Many agricultural and forest ecosystems have been identified as secondary N sources. In the present study, the input-output budget of inorganic N in a small forested watershed of subtropical China was investigated. Inorganic N wet deposition and discharge by stream water were monitored from March, 2007 to February, 2009. The concentrations and fluxes of inorganic N in wet precipitation and stream water and net retention of N were calculated. Global N input by dry deposition and biological fixation and N output by denitrification for forested watersheds elsewhere were reported as references to evaluate whether the studied forested watershed is a source or a sink for N. The results show that the inorganic N output by the stream water is mainly caused by NO3(-)-N even though the input is dominated by NH4(+)-N. The mean flux of inorganic N input by wet precipitation and output by stream water is 1.672 and 0.537 g N/(m2 x yr), respectively, which indicates that most of inorganic N input is retained in the forested watershed. Net retention of inorganic N reaches 1.135 g N/(m2 x yr) considering wet precipitation as the main input and stream water as the main output. If N input by dry deposition and biological fixation and output by denitrification are taken into account, this subtropical forested watershed currently acts as a considerable sink for N, with a net sink ranging from 1.309 to 1.913 g N/(m2 x yr) which may enhance carbon sequestration of the terrestrial ecosystem.

  14. Carbon stocks and sinks in forestry for the unitéd Kingdom greenhouse gas inventory. COST E21 Workshop. Contribution of forests and forestry to mitigate greenhouse effects. Joensuu (Finland. 28-30 Sep 2000

    Directory of Open Access Journals (Sweden)

    Milne R.

    2000-01-01

    Full Text Available Afforestation in the UK has been significant and continuing since 1920 (up to 30,000 ha per year. Planting data is used to drive a dynamic process-based carbon accounting model (C-Flow to estimate removals of atmospheric CO2 to these forests. It is assumed that the afforestation can be represented by the characteristics of Sitka spruce for conifers and beech for broadleaves. The present area of forest considered for these estimates is 1.6 millions ha. In 1990 the uptake to trees, litter, soil and products was 2.6 terragramme C, rising to 2.8 terragramme C in 1998. Deforestation is believed to be small. Supporting measurements show that the model predicts long term uptake by conifers well but that losses from planted peat shortly after establishment need further consideration. Process modelling of beech growth suggests that it is primarily dependant on atmospheric CO2 concentration and not on stomatal control per se. UK research priorities relevant to preparation of GHG (greenhouse gas Inventories are presented.

  15. Authigenic Carbonate and the History of the Global Carbon Cycle

    Science.gov (United States)

    Schrag, Daniel P.; Higgins, John. A.; Macdonald, Francis A.; Johnston, David T.

    2013-02-01

    We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2 or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

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

    Directory of Open Access Journals (Sweden)

    M. R. Raupach

    2014-07-01

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

  17. Regulation of assimilate import into sink organs: Update on molecular drivers of sink strength

    Directory of Open Access Journals (Sweden)

    Saadia eBihmidine

    2013-06-01

    Full Text Available Recent developments have altered our view of molecular mechanisms that determine sink strength, defined here as the capacity of non-photosynthetic structures to compete for import of photoassimilates. We review new findings from diverse systems, including stems, seeds, flowers, and fruits. An important advance has been the identification of new transporters and facilitators with major roles in the accumulation and equilibration of sugars at a cellular level. Exactly where each exerts its effect varies among systems. Sugarcane and sweet sorghum stems, for example, both accumulate high levels of sucrose, but may do so via different paths. The distinction is central to strategies for targeted manipulation of sink strength using transporter genes, and shows the importance of system-specific analyses. Another major advance has been the identification of deep hypoxia as a feature of normal grain development. This means that molecular drivers of sink strength in endosperm operate in very low oxygen levels, and under metabolic conditions quite different than previously assumed. Successful enhancement of sink strength has nonetheless been achieved in grains by up-regulating genes for starch biosynthesis. Additionally, our understanding of sink strength is enhanced by awareness of the dual roles played by invertases (INV, not only in sucrose metabolism, but also in production of the hexose sugar signals that regulate cell-cycle and cell-division programs. These contributions of INV to cell expansion and division prove to be vital for establishment of young sinks ranging from flowers to fruit. Since INV genes are themselves sugar-responsive feast genes, they can mediate a feed-forward enhancement of sink strength when assimilates are abundant. Greater overall productivity and yield have thus been attained in key instances, indicating that even broader enhancements may be achievable as we discover the detailed molecular mechanisms that drive sink strength

  18. Regulation of assimilate import into sink organs: update on molecular drivers of sink strength.

    Science.gov (United States)

    Bihmidine, Saadia; Hunter, Charles T; Johns, Christine E; Koch, Karen E; Braun, David M

    2013-01-01

    Recent developments have altered our view of molecular mechanisms that determine sink strength, defined here as the capacity of non-photosynthetic structures to compete for import of photoassimilates. We review new findings from diverse systems, including stems, seeds, flowers, and fruits. An important advance has been the identification of new transporters and facilitators with major roles in the accumulation and equilibration of sugars at a cellular level. Exactly where each exerts its effect varies among systems. Sugarcane and sweet sorghum stems, for example, both accumulate high levels of sucrose, but may do so via different paths. The distinction is central to strategies for targeted manipulation of sink strength using transporter genes, and shows the importance of system-specific analyses. Another major advance has been the identification of deep hypoxia as a feature of normal grain development. This means that molecular drivers of sink strength in endosperm operate in very low oxygen levels, and under metabolic conditions quite different than previously assumed. Successful enhancement of sink strength has nonetheless been achieved in grains by up-regulating genes for starch biosynthesis. Additionally, our understanding of sink strength is enhanced by awareness of the dual roles played by invertases (INVs), not only in sucrose metabolism, but also in production of the hexose sugar signals that regulate cell cycle and cell division programs. These contributions of INV to cell expansion and division prove to be vital for establishment of young sinks ranging from flowers to fruit. Since INV genes are themselves sugar-responsive "feast genes," they can mediate a feed-forward enhancement of sink strength when assimilates are abundant. Greater overall productivity and yield have thus been attained in key instances, indicating that even broader enhancements may be achievable as we discover the detailed molecular mechanisms that drive sink strength in diverse

  19. The potential contribution of sinks to meeting Kyoto Protocol commitments

    DEFF Research Database (Denmark)

    Missfeldt, F.; Haites, E.

    2001-01-01

    The Kyoto Protocol to the climate convention makes provision for sink enhancement activities to contribute to meeting the greenhouse gas emissions limitation commitments of industrialised countries. This paper analyses the potential contribution of sink enhancement activities to meeting commitments...

  20. Seeking a geochemical identifier for authigenic carbonate.

    Science.gov (United States)

    Zhao, Ming-Yu; Zheng, Yong-Fei; Zhao, Yan-Yan

    2016-03-07

    Authigenic carbonate was recently invoked as a third major global carbon sink in addition to primary marine carbonate and organic carbon. Distinguishing the two carbonate sinks is fundamental to our understanding of Earth's carbon cycle and its role in regulating the evolution of atmospheric oxygen. Here, using microscale geochemical measurements of carbonates in Early Triassic strata, we show that the growth of authigenic carbonate follows a different trajectory from primary marine carbonate in a cross-plot of uranium concentration and carbon isotope composition. Thus, a combination of the two geochemical variables is able to distinguish between the two carbonate sinks. The temporal distribution of authigenic carbonates in the Early Triassic strata suggests that the increase in the extent of carbonate authigenesis acted as a negative feedback to the elevated atmospheric CO2 concentration.

  1. Asymptotic Behaviour Near a Nonlinear Sink

    CERN Document Server

    Calder, Matt S

    2010-01-01

    In this paper, we will explore an iterative procedure to determine the detailed asymptotic behaviour of solutions of a certain class of nonlinear vector differential equations which approach a nonlinear sink as time tends to infinity. This procedure is indifferent to resonance in the eigenvalues. Moreover, we will address the writing of one component in terms of the other in the case of a planar system. Examples will be given, notably the Michaelis-Menten mechanism of enzyme kinetics.

  2. Numerical topology optimization of heat sinks

    OpenAIRE

    Van Oevelen, Tijs; Baelmans, Martine

    2014-01-01

    The availability of flexible production techniques challenges their full exploitation during thermo-hydraulic design of micro heat sinks. In this context, a systematic approach capable to take advantage of the practically unlimited design freedom is highly desirable. Therefore, we propose to use topology optimization, a numerical design optimization method well-established in structural mechanics problems. In this paper, the fundamentals of topology optimization, and its application in thermo...

  3. An improved sink particle algorithm for SPH simulations

    Science.gov (United States)

    Hubber, D. A.; Walch, S.; Whitworth, A. P.

    2013-04-01

    Numerical simulations of star formation frequently rely on the implementation of sink particles: (a) to avoid expending computational resource on the detailed internal physics of individual collapsing protostars, (b) to derive mass functions, binary statistics and clustering kinematics (and hence to make comparisons with observation), and (c) to model radiative and mechanical feedback; sink particles are also used in other contexts, for example to represent accreting black holes in galactic nuclei. We present a new algorithm for creating and evolving sink particles in smoothed particle hydrodynamic (SPH) simulations, which appears to represent a significant improvement over existing algorithms - particularly in situations where sinks are introduced after the gas has become optically thick to its own cooling radiation and started to heat up by adiabatic compression. (i) It avoids spurious creation of sinks. (ii) It regulates the accretion of matter on to a sink so as to mitigate non-physical perturbations in the vicinity of the sink. (iii) Sinks accrete matter, but the associated angular momentum is transferred back to the surrounding medium. With the new algorithm - and modulo the need to invoke sufficient resolution to capture the physics preceding sink formation - the properties of sinks formed in simulations are essentially independent of the user-defined parameters of sink creation, or the number of SPH particles used.

  4. An improved sink particle algorithm for SPH simulations

    CERN Document Server

    Hubber, D A; Whitworth, A P

    2013-01-01

    Numerical simulations of star formation frequently rely on the implementation of sink particles, (a) to avoid expending computational resource on the detailed internal physics of individual collapsing protostars, (b) to derive mass functions, binary statistics and clustering kinematics (and hence to make comparisons with observation), and (c) to model radiative and mechanical feedback; sink particles are also used in other contexts, for example to represent accreting black holes in galactic nuclei. We present a new algorithm for creating and evolving sink particles in SPH simulations, which appears to represent a significant improvement over existing algorithms {\\refrpt -- particularly in situations where sinks are introduced after the gas has become optically thick to its own cooling radiation and started to heat up by adiabatic compression}. (i) It avoids spurious creation of sinks. (ii) It regulates the accretion of matter onto a sink so as to mitigate non-physical perturbations in the vicinity of the sink...

  5. Rapid organic matter sulfurization in sinking particles from the Cariaco Basin water column

    Science.gov (United States)

    Raven, Morgan Reed; Sessions, Alex L.; Adkins, Jess F.; Thunell, Robert C.

    2016-10-01

    Organic matter (OM) burial in marine sediments is a potentially important control on global climate and the long-term redox state of the earth's surface. Still, we have only a limited understanding of the processes that stabilize OM and facilitate its preservation in the geologic record. Abiotic reactions with (poly)sulfides can enhance the preservation potential of OM, but for this process to be significant it needs to compete with OM remineralization, the majority of which occurs before sinking particles reach the sea floor. Here we investigate whether OM sulfurization occurs within sinking particles in the Cariaco Basin, a modern sulfidic marine environment with high rates of OM burial. Proto-kerogen in sinking particles is frequently more sulfur-rich and 34S-depleted than expectations for biomass, with a composition that is difficult to explain by mixing with resuspended or terrigenous material. Instead, it appears that sulfur is being incorporated into OM on a timescale of days in sinking particles. The flux of this abiogenic organic S from particles is equivalent to approximately two-thirds of the total amount of proto-kerogen S at 10 cm depth in underlying sediments (ODP Core 1002B); after 6000 years of more gradual sulfurization reactions, potential water column sources are still equivalent to nearly half of the total proto-kerogen S in Cariaco sediments. Water column sulfurization is most extensive during periods of upwelling and high primary productivity and appears to involve elemental S, possibly via polysulfides. This process has the potential to deliver large amounts of OM to the sediments by making it less available for remineralization, generating OM-rich deposits. It represents a potentially dynamic sink in the global carbon cycle that can respond to changes in environmental conditions, including the size and intensity of O2-depleted environments. Water column OM sulfurization could also have played a more significant role in the carbon cycle

  6. Atmospheric carbon dioxide and the global carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Trabalka, J R [ed.

    1985-12-01

    This state-of-the-art volume presents discussions on the global cycle of carbon, the dynamic balance among global atmospheric CO2 sources and sinks. Separate abstracts have been prepared for the individual papers. (ACR)

  7. Seasonal inter-relationships in atmospheric methane and companion δ13C values: effects of sinks and sources

    Science.gov (United States)

    Lassey, K. R.; Allan, W.; Fletcher, S. E. Mikaloff

    2011-07-01

    Recent developments in applying carbon-isotope information to better understand regional and global methane budgets infer a strong role by a highly fractionating seasonal sink such as atomic chlorine. Specifically, OH as the predominant seasonal sink cannot account for the ‘phase ellipses’ based on observed seasonal cycles of methane mixing ratio and isotope ratio, δ13C. Although a strong role by atomic chlorine is inferred empirically, open questions remain about the interplay between sources and sinks in determining the properties of phase ellipses. This paper employs a simple didactic model of the seasonal cycling of atmospheric methane to understand such interplay. We demonstrate that a single seasonal sink and seasonal source act together to imprint anti-phase seasonalities on atmospheric methane and δ13C, which lead to phase ellipses that collapse onto a straight line with slope characteristic of that sink. This explains empirical findings of these anti-phase relationships in three-dimensional modelling studies. We also demonstrate that multiple seasonal sinks acting with a seasonal source can yield surprising properties for the phase ellipse that not only explain some features of phase ellipses reported in modelling studies but also have the potential to explain marked inter-annual variation in phase ellipses based on observation.

  8. Seasonal inter-relationships in atmospheric methane and companion delta13C values: effects of sinks and sources

    Energy Technology Data Exchange (ETDEWEB)

    Lassey, K. R.; Mikaloff Fletcher, S. E. (NIWA, Wellington (New Zealand)), e-mail: k.lassey@niwa.co.nz; Allan, W. (Allan Planning and Research Ltd., Petone (New Zealand))

    2011-07-15

    Recent developments in applying carbon-isotope information to better understand regional and global methane budgets infer a strong role by a highly fractionating seasonal sink such as atomic chlorine. Specifically, OH as the predominant seasonal sink cannot account for the 'phase ellipses' based on observed seasonal cycles of methane mixing ratio and isotope ratio, delta13C. Although a strong role by atomic chlorine is inferred empirically, open questions remain about the interplay between sources and sinks in determining the properties of phase ellipses. This paper employs a simple didactic model of the seasonal cycling of atmospheric methane to understand such interplay. We demonstrate that a single seasonal sink and seasonal source act together to imprint anti-phase seasonalities on atmospheric methane and delta13C, which lead to phase ellipses that collapse onto a straight line with slope characteristic of that sink. This explains empirical findings of these anti-phase relationships in three-dimensional modelling studies. We also demonstrate that multiple seasonal sinks acting with a seasonal source can yield surprising properties for the phase ellipse that not only explain some features of phase ellipses reported in modelling studies but also have the potential to explain marked inter-annual variation in phase ellipses based on observation

  9. Salon sink radiculopathy: a case series.

    Science.gov (United States)

    Stitik, T P; Nadler, S F; Foye, P M

    1999-01-01

    Cervical radiculopathy can be diagnosed on physical examination with the Spurling test, which narrows neural foramina via neck extension along with coupled rotation and side-bending. In the presence of cervical radiculopathy, this test can reproduce radicular symptoms by transmitting compressive forces to affected nerve roots as they traverse the neural foramina. Treatment of cervical radiculopathy includes patient education to avoid obvious postures that exacerbate radicular symptoms and to assume positions that centralize discomfort. A potentially harmful position to which many patients are unwittingly subjected at least several times per year occurs when their hair is being shampooed in a salon sink before a haircut. This posture causes neck extension and is combined with rotation and side-bending as the patient's head is being manipulated during the shampooing. When the stylist then also applies a mild compressive force while shampooing the patient's hair, hyperextension of the neck is produced. We present two patients with cervical radiculopathy that was significantly exacerbated after the patient's hair had been shampooed in a salon sink; subsequently, these patients required oral administration of steroids. These cases illustrate that patients with suspected or known cervical radiculopathy should be forewarned to avoid this otherwise seemingly innocuous activity.

  10. Causes of sinks near Tucson, Arizona, USA

    Science.gov (United States)

    Hoffmann, John P.; Pool, Donald R.; Konieczki, A. D.; Carpenter, Michael C.

    Land subsidence in the form of sinks has occurred on and near farmlands near Tucson, Pima County, Arizona, USA. The sinks occur in alluvial deposits along the flood plain of the Santa Cruz River, and have made farmlands dangerous and unsuitable for farming. More than 1700 sinks are confined to the flood plain of the Santa Cruz River and are grouped along two north-northwestward-trending bands that are approximately parallel to the river and other flood-plain drainages. An estimated 17,000m3 of sediment have been removed in the formation of the sinks. Thirteen trenches were dug to depths of 4-6m to characterize near-surface sediments in sink and nonsink areas. Sediments below about 2m included a large percentage of dispersive clays in sink areas. Sediments in nonsink areas contain a large component of medium- to coarse-grained, moderately to well sorted sand that probably fills a paleochannel. Electromagnetic surveys support the association of silts and clays in sink areas that are highly electrically conductive relative to sand in nonsink areas. Sinks probably are caused by the near-surface process of subsurface erosion of dispersive sediments along pre-existing cracks in predominantly silt and clay sediments. The pre-existing cracks probably result from desiccation or tension that developed during periods of water-table decline and channel incision during the past 100 years or in earlier periods. Résumé Des effondrements en forme d'entonnoir se sont produits sur et près d'exploitations agricoles de Pima (Arizona). Ces entonnoirs apparaissent dans les alluvions le long de la plaine d'inondation de la rivière Santa Cruz ; ils ont rendu ces terrains dangereux et inexploitables pour l'agriculture. Plus de 1700 entonnoirs existent dans la plaine d'inondation de la rivière Santa Cruz et sont groupés en deux bandes orientées nord-nord-ouest, approximativement parallèles à la rivière et aux autres chenaux de la plaine d'inondation. Un volume de sédiments estim

  11. Source-sink relationships in radish plant

    Directory of Open Access Journals (Sweden)

    Z. Starck

    2015-05-01

    Full Text Available The problem of source-sink relationships in di- and tetraploidal radish plants grown in. hydroponic cultures was investigated in two stages of their development: with intensively growing swollen hypocotyl and in the period of actively accumulating nutrients in the storage organ. It was found, that the proportion, between the mass of organs, their RGR and NAR was very similar in di- and tetraploidal populations, probably owing to a similar rate of photosynthesis and pattern of assimilates distribution. The high variability of swollen hypocotyls size is slightly correlated with the size of the whole aerial part and is not correlated with the rate of photosynthesis in leaves. Partial defoliation of radish plants did not affect the rate of photosynthesis of the remaining leaves. Only in the cotyledones the oldest donors of 14C-assimilates, a slight compensation of photosynthesis was reported. It may suggest, that the rate of photosynthesis in radish plants is not under the control of sink activity. The size of the storage organ have determined in some extent its attractive force and influenced the amount of 14C-assimilates exported from their donors. Translocation of photosynthates from the young, still growing leaves was conditioned mainly by their retention power. Therefore, in young radish plants cotyledons were the main donor of 14C-assimilates.

  12. Production, oxygen respiration rates, and sinking velocity of copepod fecal pellets: Direct measurements of ballasting by opal and calcite

    DEFF Research Database (Denmark)

    Ploug, H.; Iversen, M.H.; Koski, Marja;

    2008-01-01

    sp., T. weissflogii, and E. huxleyi, respectively. The average carbon-specific respiration rate was 0.15 d(-1) independent on diet (range: 0.08-0.21 d(-1)). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets produced on T. weissflogii (322 +/- 169 m d...

  13. Carbon Dioxide and Climate.

    Science.gov (United States)

    Brewer, Peter G.

    1978-01-01

    The amount of carbon dioxide in the atmosphere is increasing at a rate that could cause significant warming of the Earth's climate in the not too distant future. Oceanographers are studying the role of the ocean as a source of carbon dioxide and as a sink for the gas. (Author/BB)

  14. Investigation of Heat Sink Efficiency for Electronic Component Cooling Applications

    DEFF Research Database (Denmark)

    Staliulionis, Ž.; Zhang, Zhe; Pittini, Riccardo;

    2014-01-01

    Research and optimisation of cooling of electronic components using heat sinks becomes increasingly important in modern industry. Numerical methods with experimental real-world verification are the main tools to evaluate efficiency of heat sinks or heat sink systems. Here the investigation......-imaging camera was used to measure the thermal field distribution. Ideas for future research involving improvement of the experimental setup and modeling verification are given....

  15. Efficient Information Dissemination in Wireless Sensor Networks using Mobile Sinks

    Science.gov (United States)

    2006-10-01

    a large number of mobile sinks. They describe the SEAD (Scalable Energy-efficient Asynchronous Dissemination) protocol to build and maintain an...the most loaded sensor node ( Emax ) can be approximated as follows. Sensors that are only one hop away from the sink towards the event location (i.e...is proportional to the ratio of A1/A0, i.e., (12) where (13) (14) Thus, Emax is a linear function of the distance d between the sink

  16. Electronically controlled heat sink for high-power laser diodes

    Science.gov (United States)

    Vetrovec, John

    2009-05-01

    We report on a novel electronically controlled active heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink receives diode waste heat at high flux and transfers it at reduced flux to environment, coolant fluid, heat pipe, or structure. Thermal conductance of the heat sink is electronically adjustable, allowing for precise control of diode temperature and the diode light wavelength. When pumping solid-state or alkaline vapor lasers, diode wavelength can be precisely temperature-tuned to the gain medium absorption features. This paper presents the heat sink physics, engineering design, and performance modeling.

  17. Physics of sinking and selection of plankton cell size

    Energy Technology Data Exchange (ETDEWEB)

    Sciascia, R., E-mail: r.sciascia@isac.cnr.it [Institute of Atmospheric Sciences and Climate, CNR, Corso Fiume, 4, 10133 Torino (Italy); Doctorate Program in Fluid Dynamics, Politecnico di Torino (Italy); De Monte, S. [CNRS, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Université Pierre et Marie Curie-Paris 6, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Institut de Biologie de l' Ecole Normale Supérieure, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Provenzale, A. [Institute of Atmospheric Sciences and Climate, CNR, Corso Fiume, 4, 10133 Torino (Italy)

    2013-02-04

    Gravitational sinking in the water column is known to affect size composition of planktonic communities. One important driver toward the reduction of plankton size is the fact that larger cells tend to sink faster below the euphotic layer. In this work, we discuss the role of gravitational sinking in driving cell size selection, showing that the outcome of phytoplankton competition is determined by the dependence of sinking velocity on cell size, shape, and on the temporal variability associated with turbulence. This opens a question on whether regional modulations of the turbulence intensity could affect size distribution of planktonic communities.

  18. Sources and sinks of stratospheric water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Ellsaesser, H.W.

    1979-11-01

    A tutorial review of the understanding of stratospheric H/sub 2/O and the processes controlling it is presented. Paradoxes posed by currently available observational data are cited and suggestions made as to how they might be resolved. Such resolution appears to require: that the bulk of our current data provides unrepresentative and misleading vertical and latitudinal H/sub 2/O gradients immediately downstream from the tropical tropopause; and, that there exists within the troposphere a mechanism different from or in addition to the tropical tropopause cold trap for drying air to the mixing ratios found in the lower stratosphere. Satisfaction of these requirements will reconcile much heretofore puzzling observational data and will obviate the necessity for a stratospheric sink for H/sub 2/O.

  19. Sound Wave in Vortex with Sink

    CERN Document Server

    Basak, S

    2003-01-01

    Using Komar's definition, we give expressions for the mass and angular momentum of a rotating acoustic black hole. We show that the mass and angular momentum so defined, obey the equilibrium version of the first law of Black Hole thermodynamics. We also show that when a phonon passes by a vortex with a sink, its trajectory is bent. The angle of bending of the sound wave to leading order is quadratic in $A/cb$ and $B/cb$, where $b$ is the impact parameter and $A$ and $B$ are the parameters in the velocity of the fluid flow. The time delay in the propagation of sound wave which to first order depends only on $B/c^2$ and is independent of $A$.

  20. Biogeochemical properties of sinking particles in the southwestern part of the East Sea (Japan Sea)

    Science.gov (United States)

    Kim, Minkyoung; Hwang, Jeomshik; Rho, TaeKeun; Lee, Tongsup; Kang, Dong-Jin; Chang, Kyung-Il; Noh, Suyun; Joo, HuiTae; Kwak, Jung Hyun; Kang, Chang-Keun; Kim, Kyung-Ryul

    2017-03-01

    This study investigates the biological pump system in the East Sea (Japan Sea) by conducting an analysis of the total particle flux, biogenic material composition, and carbon isotope ratios of sinking particles. The samples were collected for one year starting from March 2011 using time-series sediment traps deployed at depths of 1040 m and 2280 m on bottom-tethered mooring at Station EC1 (37.33°N, 131.45°E; 2300 m water depth) in the Ulleung Basin (UB), southwestern part of the East Sea. The temporal variation in the particulate organic carbon (POC) flux at 1000 m shows a good relationship with the primary production in the corresponding surface water. The ratio of POC flux at 1000 m to satellite-based primary production in the corresponding region in the UB was 3%, which is comparable to the values of 2 to 5% estimated from previous studies of other part of the East Sea. The lithogenic material accounted for > 17% of the sinking particles at 1000 m and for a larger fraction of 40 to 60% at 2280 m. The radiocarbon contents of the sinking POC at both trap depths imply the additional supply of aged POC, with a much greater contribution at 2280 m. Overall, the particle flux in the deep interior of the East Sea appears to be controlled by the supply of complex sources, including aeolian input, the lateral supply of resuspended sediments, and biological production in the surface water.

  1. Geochemical characteristics of sinking particles in the Tonga arc hydrothermal vent field, southwestern Pacific

    Science.gov (United States)

    Kim, Hyung Jeek; Kim, Jonguk; Pak, Sang Joon; Ju, Se-Jong; Yoo, Chan Min; Kim, Hyun Sub; Lee, Kyeong Yong; Hwang, Jeomshik

    2016-10-01

    Studies of sinking particles associated with hydrothermal vent fluids may help us to quantify mass transformation processes between hydrothermal vent plumes and deposits. Such studies may also help us understand how various types of hydrothermal systems influence particle flux and composition. However, the nature of particle precipitation out of hydrothermal vent plumes in the volcanic arcs of convergent plate boundaries has not been well studied, nor have the characteristics of such particles been compared with the characteristics of sinking particles at divergent boundaries. We examined sinking particles collected by sediment traps for about 10 days at two sites, each within 200 m of identified hydrothermal vents in the south Tonga arc of the southwestern Pacific. The total mass flux was several-fold higher than in the non-hydrothermal southwest tropical Pacific. The contribution of non-biogenic materials was dominant (over 72%) and the contribution of metals such as Fe, Mn, Cu, and Zn was very high compared to their average levels in the upper continental crust. The particle flux and composition indicate that hydrothermal authigenic particles are the dominant source of the collected sinking particles. Overall, our elemental ratios are similar to observations of particles at the divergent plate boundary in the East Pacific Rise (EPR). Thus, the nature of the hydrothermal particles collected in the south Tonga arc is probably not drastically different from particles in the EPR region. However, we observed consistent differences between the two sites within the Tonga arc, in terms of the contribution of non-biogenic material, the radiocarbon content of sinking particulate organic carbon, the ratios of iron to other metals (e.g. Cu/Fe and Zn/Fe), and plume maturity indices (e.g. S/Fe). This heterogeneity within the Tonga arc is likely caused by differences in physical environment such as water depth, phase separation due to subcritical boiling and associated sub

  2. The significance of carbon-enriched dust for global carbon accounting

    Science.gov (United States)

    Soil carbon stores amount to 54% of the terrestrial carbon pool and twice the atmospheric carbon pool, but soil organic carbon (SOC) can be transient. There is an ongoing debate about whether soils are a net source or sink of carbon, and understanding the role of aeolian processes in SOC erosion, tr...

  3. Performance analysis of nanofluid-cooled microchannel heat sinks

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, T.-H. [Department of Mechanical Engineering, Wufeng Institute of Technology, Chia-Yi 621, Taiwan (China); Chein Reiyu [Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 402, Taiwan (China)], E-mail: rychein@dragon.nchu.edu.tw

    2007-10-15

    Microchannel heat sink (MCHS) performance using copper-water (Cu-H{sub 2}O) and carbon nanotube-water (CNT-H{sub 2}O) nanofluids as coolants is addressed analytically in this study. The velocity and temperature distributions in the MCHS were obtained by modeling the MCHS as a porous media. The resulting velocity and temperature were then used to evaluate the thermal resistance that characterizes MCHS performance. It was found that the nanofluid reduced the temperature difference between the MCHS bottom wall and bulk nanofluid compared with that from pure fluid. This temperature difference produces a reduction in conductive thermal resistance, which is one of the two sources contributing the total thermal resistance of the MCHS. The other source of thermal resistance, termed as convective thermal resistance, was found to increase when nanofluid is employed as the coolant due to the increase in viscosity and decrease in thermal capacity. Under the condition of a given pressure drop across the MCHS, optimum values of aspect ratio and porosity that producing the minimum thermal resistance can be found. It was found that using nanofluid can enhance the MCHS performance when the porosity and aspect ratio are less than the optimum porosity and aspect ratio. When the porosity and channel aspect ratio are higher than optimum porosity and aspect ratio, the nanofluid did not produce a significant change in MCHS thermal resistance.

  4. Population dynamics of sinking phytoplankton in stratified waters

    NARCIS (Netherlands)

    Huisman, J.; Sommeijer, B.P.

    2002-01-01

    We analyze the predictions of a reaction-advection-diffusion model to pinpoint the necessary conditions for bloom development of sinking phytoplanktonspecies in stratified waters. This reveals that there are two parameter windows that can sustain sinking phytoplankton, a turbulence window and atherm

  5. Sinking in Quicksand: An Applied Approach to the Archimedes Principle

    Science.gov (United States)

    Evans, G. M.; Evans, S. C.; Moreno-Atanasio, R.

    2015-01-01

    The objective of this paper is to present a laboratory experiment that explains the phenomenon of sinking in quicksand simulated as a fluidized bed. The paper demonstrates experimentally and theoretically that the proportion of a body that sinks in quicksand depends on the volume fraction of solids and the density of the body relative to the…

  6. CO2 capture and sequestration source-sink match optimization in Jing-Jin-Ji region of China

    Institute of Scientific and Technical Information of China (English)

    Zhong ZHENG; Dan GAO; Linwei MA; Zheng LI; Weidou NI

    2009-01-01

    Carbon dioxide capture and sequestration (CCS) is considered to be an important option for climate change mitigation. A key problem for the implementation of CCS technology is the source-sink match design and optimization when considering both economic and envir-onmental requirement. This paper presents a generic-optimization-based model for the strategic planning and design of future CCS source-sink matching. The features and capabilities of the model are illustrated through a detailed case study for the Jing-Jin-Ji (Beijing, Tianjin and Hebei Province) region in China. It shows how the model helps make a compromise in arriving at a strategic decision for CCS source-sink matching by providing the tradeoff frontiers between economic and environmental perfor-mance, and the features of match solutions with the best economic performance or with the best environmental performance.

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

    Science.gov (United States)

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

    2011-12-01

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

  8. Sinks as integrative elements of the anthropogenic metabolism

    Science.gov (United States)

    Kral, Ulrich; Brunner, Paul H.

    2015-04-01

    The anthropogenic metabolism is an open system requiring exchange of materials and energy between the anthroposphere and the environment. Material and energy flows are taken from nature and become utilized by men. After utilization, the materials either remain in the anthroposphere as recycling products, or they leave the anthroposphere as waste and emission flows. To accommodate these materials without jeopardizing human and environmental health, limited natural sinks are available; thus, man-made sinks have to be provided where natural sinks are missing or overloaded. The oral presentation (1) suggests a coherent definition of the term "sink", encompassing natural and man-made processes, (2) presents a framework to analyse and evaluate anthropogenic material flows to sinks, based on the tool substance flow analysis and impact assessment methodology, and (3) applies the framework in a case study approach for selected substances such as Copper and Lead in Vienna and Perfluorooctane sulfonate in Switzerland. Finally, the numeric results are aggregated in terms of a new indicator that specifies on a regional scale which fractions of anthropogenic material flows to sinks are acceptable. The following results are obtained: In Vienna, 99% of Cu flows to natural and man-made sinks are in accordance with accepted standards. However, the 0.7% of Cu entering urban soils and the 0.3% entering receiving waters surpass the acceptable level. In the case of Pb, 92% of all flows into sinks prove to be acceptable, but 8% are disposed of in local landfills with limited capacity. For PFOS, 96% of all flows into sinks are acceptable. 4% cannot be evaluated due to a lack of normative criteria, despite posing a risk for human health and the environment. The case studies corroborate the need and constraints of sinks to accommodate inevitable anthropogenic material flows.

  9. Quantifying the Sources and Sinks of Greenhouse Gases: What Does It Take to Satisfy Scientific and Decision-Making Needs?

    Science.gov (United States)

    Davis, K. J.; Keller, K.; Ogle, S. M.; Smith, S.

    2014-12-01

    Changes in the sources and sinks of greenhouse gases (GHGs) are key drivers of anthropogenic climate change. It is hence not surprising that current and emerging U.S. governmental science priorities and programs focused on climate change (e.g. a U.S. Carbon Cycle Science Plan; the U.S. Carbon Cycle Science Program, the U.S. Global Change Research Program, Executive Order 13653 'Preparing the U.S. for the Impacts of Climate Change') all call for an improved understanding of these sources and sinks.. Measurements of the total atmospheric burden of these gases are well established, but measurements of their sources and sinks are difficult to make over spatial and temporal scales that are relevant for scientific and decisionmaking needs. Quantifying the uncertainty in these measurements is particularly challenging. This talk reviews the intersection of the state of knowledge of GHG sources and sinks, focusing in particular on CO2 and CH4, and science and decision-making needs for this information. Different science and decision-making needs require differing levels of uncertainty. A number of high-priority needs (early detection of changes in the Earth system, projections of future climate, support of markets or regulations) often require a high degree of accuracy and/or precision. We will critically evaluate current U.S. planning to documents to infer current perceived needs for GHG source/sink quantification, attempting to translate these needs into quantitative uncertainty metrics. We will compare these perceived needs with the current state of the art of GHG source/sink quantification, including the apparent pattern of systematic differences between so-called "top down" and "bottom-up" flux estimates. This comparison will enable us to identify where needs can be readily satisfied, and where gaps in technology exist. Finally, we will examine what steps could be taken to close existing gaps.

  10. Extinction debt in source-sink metacommunities.

    Directory of Open Access Journals (Sweden)

    Nicolas Mouquet

    Full Text Available In an increasingly modified world, understanding and predicting the consequences of landscape alteration on biodiversity is a challenge for ecologists. To this end, metacommunity theory has developed to better understand the complexity of local and regional interactions that occur across larger landscapes. While metacommunity ecology has now provided several alternative models of species coexistence at different spatial scales, predictions regarding the consequences of landscape alteration have been done exclusively for the competition-colonization trade off model (CC. In this paper we investigate the effects of landscape perturbation on source-sink metacommunities. We show that habitat destruction perturbs the equilibria among species competitive effects within the metacommunity, driving both direct extinctions and an indirect extinction debt. As in CC models, we found a time lag for extinction following habitat destruction that varied in length depending upon the relative importance of direct and indirect effects. However, in contrast to CC models, we found that the less competitive species are more affected by habitat destruction. The best competitors can sometimes even be positively affected by habitat destruction, which corresponds well with the results of field studies. Our results are complementary to those results found in CC models of metacommunity dynamics. From a conservation perspective, our results illustrate that landscape alteration jeopardizes species coexistence in patchy landscapes through complex indirect effects and delayed extinctions patterns.

  11. Ornamental plants as sinks and bioindicators.

    Science.gov (United States)

    Saxena, Pallavi; Ghosh, Chirashree

    2013-01-01

    Mitigation of urban air pollution is a big challenge, especially for the metropolitan cities of the world. In an Indian metropolis like Delhi, even after the implementation of several control policies, no such remarkable change has been observed in its air quality. Globally, afforestation or greenbelt development is an effective and well-recognized pollution abatement process. The aim of our present study was to examine the biochemical response of some naturalized ornamental plant species, viz. Dracaena deremensis, Tagetes erecta, Rosa indica and Dianthus caryophyllus. During experimental study, plants were kept at selected sites which were categorized in terms of traffic density (emission source) and vegetative pattern during winter months for 120 days. Four biochemical parameters, viz. total chlorophyll, ascorbic acid, pH, relative water contents along with Air Pollution Tolerance Indices were determined from foliar samples at each selected site. D. deremensis and T. erecta were classified under tolerant while R. indica and D. caryophyllus were marked as in sensitive category. Based on the sensitivity of selected plant species, it has been recommended that D. deremensis and T. erecta may be used as sinks for the abatement of air pollution at highly polluted sites whereas R. indica and D. caryophyllus can be used as bioindicators.

  12. Sink property of metallic glass free surfaces.

    Science.gov (United States)

    Shao, Lin; Fu, Engang; Price, Lloyd; Chen, Di; Chen, Tianyi; Wang, Yongqiang; Xie, Guoqiang; Lucca, Don A

    2015-03-16

    When heated to a temperature close to glass transition temperature, metallic glasses (MGs) begin to crystallize. Under deformation or particle irradiation, crystallization occurs at even lower temperatures. Hence, phase instability represents an application limit for MGs. Here, we report that MG membranes of a few nanometers thickness exhibit properties different from their bulk MG counterparts. The study uses in situ transmission electron microscopy with concurrent heavy ion irradiation and annealing to observe crystallization behaviors of MGs. For relatively thick membranes, ion irradiations introduce excessive free volumes and thus induce nanocrystal formation at a temperature linearly decreasing with increasing ion fluences. For ultra-thin membranes, however, the critical temperature to initiate crystallization is about 100 K higher than the bulk glass transition temperature. Molecular dynamics simulations indicate that this effect is due to the sink property of the surfaces which can effectively remove excessive free volumes. These findings suggest that nanostructured MGs having a higher surface to volume ratio are expected to have higher crystallization resistance, which could pave new paths for materials applications in harsh environments requiring higher stabilities.

  13. Marine submicron aerosol gradients, sources and sinks

    Science.gov (United States)

    Ceburnis, Darius; Rinaldi, Matteo; Ovadnevaite, Jurgita; Martucci, Giovanni; Giulianelli, Lara; O'Dowd, Colin D.

    2016-10-01

    Aerosol principal sources and sinks over eastern North Atlantic waters were studied through the deployment of an aerosol chemistry gradient sampling system. The chemical gradients of primary and secondary aerosol components - specifically, sea salt (SS), water-insoluble organic matter (WIOM), water-soluble organic matter (WSOM), nitrate, ammonium, oxalate, amines, methanesulfonic acid (MSA) and water-soluble organic nitrogen (WSON) - were examined in great detail. Sea salt fluxes were estimated by the boundary layer box model and ranged from 0.3 to 3.5 ng m-2 s-1 over the wind speed range of 5-12 m s-1 and compared well with the derived fluxes from existing sea salt source parameterisations. The observed seasonal pattern of sea salt gradients was mainly driven by wind stress in addition to the yet unquantified effect of marine OM modifying fractional contributions of SS and OM in sea spray. WIOM gradients were a complex combination of rising and waning biological activity, especially in the flux footprint area, and wind-driven primary sea spray production supporting the coupling of recently developed sea spray and marine OM parameterisations.

  14. Remote Sensing of Greenhouse Gases and Their Sources and Sinks

    Science.gov (United States)

    Butz, Andre; Babenhauserheide, Arne; Bertleff, Marco; Checa-Garcia, Ramiro; Hahne, Philipp; Hase, Frank; Klappenbach, Friedrich; Kostinek, Julian; Aben, Ilse; Hasekamp, Otto; Landgraf, Jochen; Galli, Andre; Basu, Sourish

    2014-06-01

    The man-made emissions of the greenhouse gases carbon dioxide (CO2) and methane (CH4) are considered the main drivers of anthropogenically induced climate change. Major uncertainties persist when it comes to quantifying regional scale surface fluxes of these gases or predicting the evolution of the relevant source/sink processes in a changing climate. Remote sensing of the atmospheric greenhouse gas concentrations from space-borne and ground-based platforms offers the opportunity to significantly advance our knowledge on spatial and temporal scales that are suitable for process attribution and mitigation actions. Overall, the most promising remote-sensing strategy exploits the rotational-vibrational absorption of CO2 and CH4 in sunlight penetrating the Earth's atmosphere. Typically, satellite sounders such as GOSAT (Greenhouse Gases Observing Satellite), OCO-2 (Orbiting Carbon Observatory), and S5P (Sentinel-5 precursor) as well as the ground-based spectrometers of the TCCON (Total Carbon Column Observing Network) cover various CO2, CH4, and O2 absorption bands in the near and shortwave infrared spectral range between 0.75 micron (13400cm-1) and 2.5 micron (4000cm-1). Accuracy of the inferred gas concentrations is contingent on the accuracy of the adopted spectroscopic parameters and spectroscopic models available in these spectral regions. Here, I will report on recent achievements and challenges within our greenhouse-gas remote-sensing activities mainly focusing on the GOSAT observational record. Since its launch in early 2009, the Fourier Transform Spectrometer onboard GOSAT delivers solar absorption spectra with good spectral resolution and high signal-to-noise. It has been shown that the CO2 and CH4 retrievals from these observations can achieve an accuracy on the order of fractions of a percent which makes them suitable for tracking regional scale source/sink processes and their response to climate events. In order to achieve the required accuracy, it is

  15. Soil management options to sequester carbon and mitigate the greenhouse effect

    NARCIS (Netherlands)

    Batjes, N.H.

    2000-01-01

    The imbalance between global sources and sinks in the global budget of atmospheric CO2 is one of the most important problems in the study of global change. At present there is a 'missing sink' of about 1-2 Pg C yr -1. It is likely that a major part of this sink for carbon is to be found in the funct

  16. Maximizing Lifetime of Wireless Sensor Networks with Mobile Sink Nodes

    Directory of Open Access Journals (Sweden)

    Yourong Chen

    2014-01-01

    Full Text Available In order to maximize network lifetime and balance energy consumption when sink nodes can move, maximizing lifetime of wireless sensor networks with mobile sink nodes (MLMS is researched. The movement path selection method of sink nodes is proposed. Modified subtractive clustering method, k-means method, and nearest neighbor interpolation method are used to obtain the movement paths. The lifetime optimization model is established under flow constraint, energy consumption constraint, link transmission constraint, and other constraints. The model is solved from the perspective of static and mobile data gathering of sink nodes. Subgradient method is used to solve the lifetime optimization model when one sink node stays at one anchor location. Geometric method is used to evaluate the amount of gathering data when sink nodes are moving. Finally, all sensor nodes transmit data according to the optimal data transmission scheme. Sink nodes gather the data along the shortest movement paths. Simulation results show that MLMS can prolong network lifetime, balance node energy consumption, and reduce data gathering latency under appropriate parameters. Under certain conditions, it outperforms Ratio_w, TPGF, RCC, and GRND.

  17. Impingement heat sinks for air cooled high power electronic modules

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.S.; Holahan, M.F. [IBM Corp., Rochester, MN (United States)

    1995-12-31

    The subject of the present work is a parallel plate heat sink that is designed so that the air flow impinges at the fin tips and exhausts over the two open side faces. This type of design attempts to achieve an air flow direction that is substantially opposite to the heat flow direction within the fins so as to exploit the greater heat transfer effectiveness of counterflow heat exchange. A one dimensional model of the heat sink was developed with the assumption of air flow from the fin tips to the fin base. This simplified model was used to identify an initial heat sink geometry to cool a specific multichip module. Computational Fluid Dynamics models that account for the actual flow pattern within the heat sink were used to study a range of variations to the initial geometry and to identify the best geometry over the range examined. Experimental heat transfer and pressure drop data is reported for two heat sink prototypes. The test data is in good agreement with CFD predictions. Suitable correlations for the heat sink thermal resistance and pressure drop versus the air flow rate are developed. The developed heat sink demonstrated an area specific thermal resistance better than 8.7 C (W/cm{sup 2}).

  18. Intrinsic and extrinsic drivers of source-sink dynamics.

    Science.gov (United States)

    Heinrichs, Julie A; Lawler, Joshua J; Schumaker, Nathan H

    2016-02-01

    Many factors affect the presence and exchange of individuals among subpopulations and influence not only the emergence, but the strength of ensuing source-sink dynamics within metapopulations. Yet their relative contributions remain largely unexplored. To help identify the characteristics of empirical systems that are likely to exhibit strong versus weak source-sink dynamics and inform their differential management, we compared the relative roles of influential factors in strengthening source-sink dynamics. In a series of controlled experiments within a spatially explicit individual-based model framework, we varied patch quality, patch size, the dispersion of high- and low-quality patches, population growth rates, dispersal distances, and environmental stochasticity in a factorial design. We then recorded source-sink dynamics that emerged from the simulated habitat and population factors. Long-term differences in births and deaths were quantified for sources and sinks in each system and used in a statistical model to rank the influences of key factors. Our results suggest that systems with species capable of rapid growth, occupying habitat patches with more disparate qualities, with interspersed higher- and lower-quality habitats, and that experience relatively stable environments (i.e., fewer negative perturbations) are more likely to exhibit strong source-sink dynamics. Strong source-sink dynamics emerged under diverse combinations of factors, suggesting that simple inferences of process from pattern will likely be inadequate to predict and assess the strength of source-sink dynamics. Our results also suggest that it may be more difficult to detect and accurately measure source-sink dynamics in slow-growing populations, highly variable environments, and where a subtle gradient of habitat quality exists.

  19. On sources and sinks of phosgene in the troposphere

    Science.gov (United States)

    Helas, G.; Wilson, S. R.

    Source and sink processes of phosgene (COCl 2) in the troposphere are reviewed. Sources are identified as decomposition of chlorinated hydrocarbons in both troposphere and stratosphere, which can be expected to increase in the future. Sinks are dry deposition and hydrolysis which, within clouds, is of the time scale of hours, and photolysis, which will not be of importance in the troposphere. Though above the cloud layer the lifetime of phosgene is expected to be greater than 10 years, hydrolysis during the transit through clouds and dry deposition will be the dominant sink, leading to an estimated residence time of approximately a few days.

  20. Bounds on the dynamics of sink populations with noisy immigration

    DEFF Research Database (Denmark)

    Eager, Eric Alan; Guiver, Chris; Hodgson, Dave

    2014-01-01

    Sink populations are doomed to decline to extinction in the absence of immigration. The dynamics of sink populations are not easily modelled using the standard framework of per capita rates of immigration, because numbers of immigrants are determined by extrinsic sources (for example, source...... populations, or population managers). Here we appeal to a systems and control framework to place upper and lower bounds on both the transient and future dynamics of sink populations that are subject to noisy immigration. Immigration has a number of interpretations and can fit a wide variety of models found...

  1. Differential responses of sugar, organic acids and anthocyanins to source-sink modulation in Cabernet Sauvignon and Sangiovese grapevines.

    Science.gov (United States)

    Bobeica, Natalia; Poni, Stefano; Hilbert, Ghislaine; Renaud, Christel; Gomès, Eric; Delrot, Serge; Dai, Zhanwu

    2015-01-01

    Grape berry composition mainly consists of primary and secondary metabolites. Both are sensitive to environment and viticultural management. As a consequence, climate change can affect berry composition and modify wine quality and typicity. Leaf removal techniques can impact berry composition by modulating the source-to-sink balance and, in turn, may mitigate some undesired effects due to climate change. The present study investigated the balance between technological maturity parameters such as sugars and organic acids, and phenolic maturity parameters such as anthocyanins in response to source-sink modulation. Sugar, organic acid, and anthocyanin profiles were compared under two contrasting carbon supply levels in berries of cv. Cabernet Sauvignon and Sangiovese collected at 9 and 14 developmental stages respectively. In addition, whole-canopy net carbon exchange rate was monitored for Sangiovese vines and a mathematic model was used to calculate the balance between carbon fixation and berry sugar accumulation. Carbon limitation affected neither berry size nor the concentration of organic acids at harvest. However, it significantly reduced the accumulation of sugars and total anthocyanins in both cultivars. Most interestingly, carbon limitation decreased total anthocyanin concentration by 84.3% as compared to the non source-limited control, whereas it decreased sugar concentration only by 27.1%. This suggests that carbon limitation led to a strong imbalance between sugars and anthocyanins. Moreover, carbon limitation affected anthocyanin profiles in a cultivar dependent manner. Mathematical analysis of carbon-balance indicated that berries used a higher proportion of fixed carbon for sugar accumulation under carbon limitation (76.9%) than under carbon sufficiency (48%). Thus, under carbon limitation, the grape berry can manage the metabolic fate of carbon in such a way that sugar accumulation is maintained at the expense of secondary metabolites.

  2. Differential responses of sugar, organic acids and anthocyanins to source-sink modulation in Cabernet Sauvignon and Sangiovese grapevines

    Directory of Open Access Journals (Sweden)

    Natalia eBobeica

    2015-05-01

    Full Text Available Grape berry composition mainly consists of primary and secondary metabolites. Both are sensitive to environment and viticultural management. As a consequence, climate change can affect berry composition and modify wine quality and typicity. Leaf removal techniques can impact berry composition by modulating the source-to-sink balance and, in turn, may mitigate some undesired effects due to climate change. The present study investigated the balance between technological maturity parameters such as sugars and organic acids, and phenolic maturity parameters such as anthocyanins in response to source-sink modulation. Sugar, organic acid, and anthocyanin profiles were compared under two contrasting carbon supply levels in berries of cv. Cabernet Sauvignon and Sangiovese collected at 9 and 14 developmental stages respectively. In addition, whole-canopy net carbon exchange rate was monitored for Sangiovese vines and a mathematic model was used to calculate the balance between carbon fixation and berry sugar accumulation. Carbon limitation affected neither berry size nor the concentration of organic acids at harvest. However, it significantly reduced the accumulation of sugars and total anthocyanins in both cultivars. Most interestingly, carbon limitation decreased total anthocyanin concentration by 84.3 % as compared to the non source-limited control, whereas it decreased sugar concentration only by 27.1 %. This suggests that carbon limitation led to a strong imbalance between sugars and anthocyanins. Moreover, carbon limitation affected anthocyanin profiles in a cultivar dependent manner. Mathematical analysis of carbon-balance indicated that berries used a higher proportion of fixed carbon for sugar accumulation under carbon limitation (76.9% than under carbon sufficiency (48%. Thus, under carbon limitation, the grape berry can manage the metabolic fate of carbon in such a way that sugar accumulation is maintained at the expense of secondary

  3. Effects of Ocean Acidification on the Ballast of Surface Aggregates Sinking through the Twilight Zone

    OpenAIRE

    de Jesus Mendes, Pedro A.; Laurenz Thomsen

    2012-01-01

    The dissolution of CaCO(3) is one of the ways ocean acidification can, potentially, greatly affect the ballast of aggregates. A diminution of the ballast could reduce the settling speed of aggregates, resulting in a change in the carbon flux to the deep sea. This would mean lower amounts of more refractory organic matter reaching the ocean floor. This work aimed to determine the effect of ocean acidification on the ballast of sinking surface aggregates. Our hypothesis was that the decrease of...

  4. Performances of thermoelectric cooler integrated with microchannel heat sinks

    Energy Technology Data Exchange (ETDEWEB)

    Reiyu Chein; Yehong Chen [National Chung Hsing University, Taichung (Taiwan). Department of Mechanical Engineering

    2005-09-01

    In this study, experimental and theoretical studies on thermoelectric cooler (TEC) performance for cooling a refrigerated object (water in a tank) were performed. Microchannel heat sinks fabricated with etched silicon wafers were employed on the TEC hot side to dissipate heat. The measurements show that the temperature of the refrigerated object decreased with time. A theoretical model based on a lumped system was established to predict the transient behavior of the variation in temperature for the refrigerated object with time. The theoretical predicted temperature variation was in good agreement with the measured data. The relationship among the heat sink thermal resistances, TEC electric current input and minimum refrigerated objected temperature was examined based on the theoretical model. The calculated minimum temperatures were showed for the several cases of heat sink thermal resistance on the TEC hot side and electric current input. The minimum temperature can be obtained by increasing the electrical current input and decreasing the heat sink thermal resistance. (author)

  5. A Novel Mobile Sink Nodes Protocol for Grid Sensor Networks

    Directory of Open Access Journals (Sweden)

    Mei-Wen Huang

    2012-09-01

    Full Text Available The traditional wireless sensor networks (WSNs fixed the sink node in a certain place has a serious hotspot problem. The sensors closer to the sink node usually required forwarding a large amount of traffic for sensors farther from the sink node. Hotspot problem causes the nodes near the hotspot sensor node consuming much more energy than the other nodes, which seriously shortens the lifetime of the sensor networks. In the paper, it is proposed a dual mobile sink nodes protocol (DMSP which combines the balance traffic strategy in the WSNs to extend the lifetime of the sensor networks. The simulation results show that the proposed DMSP can efficiently prolong the lifetime of the WSNs.

  6. Butte Sink Wildlife Management Area [Land Status Map: Index Sheet

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This map was produced by the Division of Realty to depict landownership at Butte Sink Wildlife Management Area. It was generated from rectified aerial photography,...

  7. Lignin Depolymerization by Fungal Secretomes and a Microbial Sink

    Energy Technology Data Exchange (ETDEWEB)

    Salvachua, Davinia; Katahira, Rui; Cleveland, Nicholas S.; Khanna, Payal; Resch, Michael G.; Black, Brenna A.; Purvine, Samuel O.; Zink, Erika M.; Prieto, Alicia; Martinez, Maria J.; Martinez, Angel T.; Simmons, Blake A.; Gladden, John M.; Beckham, Gregg T.

    2016-11-21

    In Nature, powerful oxidative enzymes secreted by white rot fungi and some bacteria catalyze lignin depolymerization and some microbes are able to catabolize the resulting aromatic compounds as carbon and energy sources. Taken together, these two processes offer a potential route for microbial valorization of lignin. However, many challenges remain in realizing this concept, including that oxidative enzymes responsible for lignin depolymerization also catalyze polymerization of low molecular weight (LMW) lignin. Here, multiple basidiomycete secretomes were screened for ligninolytic enzyme activities in the presence of a residual lignin solid stream from a corn stover biorefinery, dubbed DMR-EH (Deacetylation, Mechanical Refining, and Enzymatic Hydrolysis) lignin. Two selected fungal secretomes, with high levels of laccases and peroxidases, were utilized for DMR-EH lignin depolymerization assays. The secretome from Pleurotus eryngii, which exhibited the highest laccase activity, reduced the lignin average molecular weight (Mw) by 63% and 75% at pH 7 compared to the Mw of the control treated at the same conditions and the initial DMR-EH lignin, respectively, and was applied in further depolymerization assays as a function of time. As repolymerization was observed after 3 days of incubation, an aromatic-catabolic microbe (Pseudomonas putida KT2440) was incubated with the fungal secretome and DMR-EH lignin. These experiments demonstrated that the presence of the bacterium enhances lignin depolymerization, likely due to bacterial catabolism of LMW lignin, which may partially prevent repolymerization. In addition, proteomics was also applied to the P. eryngii secretome to identify the enzymes present in the fungal cocktail utilized for the depolymerization assays, which highlighted a significant number of glucose/methanol/choline (GMC) oxidoreductases and laccases. Overall, this study demonstrates that ligninolytic enzymes can be used to partially depolymerize a solid

  8. Source-sink landscape theory and its ecological significance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Exploring the relatiouships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists."Source" and "sink" are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of "source" and "sink" could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1) In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,"source"landscape and "sink" landscape."Source" landscape contributes positively to the ecological process,while "sink" landscape is unhelpful to the ecological process.(2) Both landscapes are recognized with regard to the specific ecological process."Source" landscape in a target ecological process may change into a "sink"landscape as in another ecological process.Therefore,the ecological process should be determined before "source"or "sink" landscape were defined.(3) The key point to distinguish "source" landscape from "sink" landscape is to quantify the effect of landscape on ecological process.The positive effect is made by "source" landscape,and the negative effect by "sink" landscape.(4) For the same ecological process,the contribution of "source" landscapes may vary,and it is the same to the "sink"landscapes.It is required to determine the weight of each landscape type on ecological processes.(5) The sourcesink principle can be

  9. Novel natural convection heat sink design concepts from first principles

    OpenAIRE

    Fletcher, Derek E.

    2016-01-01

    Approved for public release; distribution is unlimited This was a two-part numerical study using ANSYS Fluent to develop novel heat sink concepts from first principles. The objective of this research was to highlight geometric structures that incorporate the principles of the stack effect to improve the heat transfer capability of a heat sink under natural convection. The first part investigated the heat transfer/fluid flow characteristics of vertically aligned tubes. The gaps between tube...

  10. An improved sink particle algorithm for SPH simulations

    OpenAIRE

    Hubber, D. A.; Walch, S.; Whitworth, A. P.

    2013-01-01

    Numerical simulations of star formation frequently rely on the implementation of sink particles, (a) to avoid expending computational resource on the detailed internal physics of individual collapsing protostars, (b) to derive mass functions, binary statistics and clustering kinematics (and hence to make comparisons with observation), and (c) to model radiative and mechanical feedback; sink particles are also used in other contexts, for example to represent accreting black holes in galactic n...

  11. Convectively driven sinks and magnetic fields in the quiet Sun

    CERN Document Server

    Requerey, Iker S; Rubio, Luis R Bellot; Pillet, Valentín Martínez; Solanki, Sami K; Schmidt, Wolfgang

    2016-01-01

    We study the relation between mesogranular flows, convectively driven sinks and magnetic fields using high spatial resolution spectropolarimetric data acquired with the Imaging Magnetograph eXperiment on board Sunrise. We obtain the horizontal velocity flow fields of two quiet-Sun regions (31.2 $\\times$ 31.2 Mm$^{2}$) via local correlation tracking. Mesogranular lanes and the central position of sinks are identified using Lagrange tracers. We find $6.7\\times10^{-2}$ sinks per Mm$^{2}$ in the two observed regions. The sinks are located at the mesogranular vertices and turn out to be associated with (1) horizontal velocity flows converging to a central point and (2) long-lived downdrafts. The spatial distribution of magnetic fields in the quiet Sun is also examined. The strongest magnetic fields are preferentially located at sinks. We find that 40 \\% of the pixels with longitudinal component of the magnetic field stronger than 500 G are located in the close neighborhood of sinks. In contrast, the small-scale ma...

  12. Why productive upwelling areas are often sources rather than sinks of CO2? – a comparative study on eddy upwellings in the South China Sea

    Directory of Open Access Journals (Sweden)

    N. Jiao

    2013-08-01

    Full Text Available Marine upwelling regions are known to be productive in carbon fixation and thus thought to be sinks of CO2, whereas many upwelling areas in the ocean are actually sources rather than sinks of CO2. To address this paradox, multiple biogeochemical parameters were investigated at two cyclonic-eddy-induced upwelling sites CE1 and CE2 in the western South China Sea. The results showed that upwelling can exert significant influences on biological activities in the euphotic zone and can either increase or decrease particulate organic carbon (POC export flux depending on upwelling conditions such as the magnitude, timing, and duration of nutrient input and consequent microbial activities. At CE2 the increase of phytoplankton biomass caused by the upwelled nutrients resulted in increase of POC export flux compared to non-eddy reference sites, while at CE1 the microbial respiration of organic carbon stimulated by the upwelled nutrients significantly contributed to the attenuation of POC export flux, aggravating outgassing of CO2. These results suggest that on top of upwelled dissolved inorganic carbon release, microbial activities stimulated by upwelled nutrients and phytoplankton labile organic carbon can play a critical role for a marine upwelling area to be a source rather than a sink of CO2. Meanwhile, we point out that even though an upwelling region is outgassing, carbon sequestration still takes place through the POC-based biological pump as well as the refractory dissolved organic carbon (RDOC-based microbial carbon pump.

  13. Disentangling Sources and Sinks of Carbonyl Sulfide in a Temperate Mountain Grassland

    Science.gov (United States)

    Wohlfahrt, G.; Hammerle, A.; Kitz, F.; Spielmann, F.

    2015-12-01

    Carbonyl sulfide (COS) is the most abundant sulfur-containing trace gas present in the troposphere at concentrations of around 500 ppt. Recent interest in COS by the ecosystem-physiological community has been sparked by the fact that COS co-diffuses into plant leaves pretty much the same way as carbon dioxide (CO2) does, but in contrast to CO2, COS is not known to be emitted by plants. Thus uptake of COS by vegetation has the potential to be used as a tracer for canopy gross photosynthesis, which cannot be measured directly, however represents a key term in the global carbon cycle. The use of COS as a tracer for canopy gross photosynthesis relies on the assumption that other sinks or sources of COS within an ecosystem are negligible, so that the COS exchange is through leaves only. Here we use concurrent COS and CO2 ecosystem-scale eddy covariance and soil chamber flux measurements together with within and above-canopy concentration profiles and an inverse Lagrangian analysis to disentangle sinks and sources of COS in a temperate mountain grassland. Preliminary results from the vegetation period 2015 suggest the soil at this grassland site to present a source of COS during daytime, which is corroborated by the inverse Lagrangian analysis which infers a COS source in the lowermost part of the canopy, while during nighttime the soil COS exchange is close to zero. At the ecosystem-scale a net uptake of COS was observed throughout the day, which in turn suggests (i) a sink for COS in the plant canopy during nighttime and (ii) a larger (compared to the net flux) gross uptake of COS by the plant canopy during daytime. Taken together our results suggest that using COS as a tracer for canopy gross photosynthesis may be less straight forward than previously thought and that further work is required to better understand the ecosystem-scale COS exchange and its drivers.

  14. Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Qianlai [Purdue University; Law, Beverly E. [Oregon State University; Baldocchi, Dennis [University of California, Berkeley; Ma, Siyan [University of California, Berkeley; Chen, Jiquan [University of Toledo, Toledo, OH; Richardson, Andrew [Harvard University; Melillo, Jerry [Marine Biological Laboratory; Davis, Ken J. [Pennsylvania State University; Hollinger, D. [USDA Forest Service; Wharton, Sonia [University of California, Davis; Falk, Matthias [University of California, Davis; Paw, U. Kyaw Tha [University of California, Davis; Oren, Ram [Duke University; Katulk, Gabriel G. [Duke University; Noormets, Asko [North Carolina State University; Fischer, Marc [Lawrence Berkeley National Laboratory (LBNL); Verma, Shashi [University of Nebraska; Suyker, A. E. [University of Nebraska, Lincoln; Cook, David R. [Argonne National Laboratory (ANL); Sun, G. [USDA Forest Service; McNulty, Steven G. [USDA Forest Service; Wofsy, Steve [Harvard University; Bolstad, Paul V [University of Minnesota; Burns, Sean [University of Colorado, Boulder; Monson, Russell K. [University of Colorado, Boulder; Curtis, Peter [Ohio State University, The, Columbus; Drake, Bert G. [Smithsonian Environmental Research Center, Edgewater, MD; Foster, David R. [Harvard University; Gu, Lianhong [ORNL; Hadley, Julian L. [Harvard University; Litvak, Marcy [University of New Mexico, Albuquerque; Martin, Timothy A. [University of Florida, Gainesville; Matamala, Roser [Argonne National Laboratory (ANL); Meyers, Tilden [NOAA, Oak Ridge, TN; Oechel, Walter C. [San Diego State University; Schmid, H. P. [Indiana University; Scott, Russell L. [USDA ARS; Torn, Margaret S. [Lawrence Berkeley National Laboratory (LBNL)

    2011-01-01

    More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr 1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr 1 over the period 2001 2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.

  15. Microbial carbon sequestration - an IRCCM research project

    Energy Technology Data Exchange (ETDEWEB)

    Boetius, A.; Wolf-Gladrow, D. [Alfred-Wegener-Institute fuer Polar- und Meeresforschung, Bremerhaven (Germany)

    2003-07-01

    The paper examines two major processes representing a sink for carbon in the ocean: (1) sedimentation of biogenic carbonate from productive surface waters and (2) carbon sequestration by methane oxidation above gas hydrate and other sites of methane seepage. The importance of understanding the submarine environments at the interface between the geo- and biosphere is stressed. 3 figs.

  16. Temperate Forest Methane Sink Diminished by Tree Emissions

    Science.gov (United States)

    Megonigal, P.; Pitz, S.

    2015-12-01

    Global budgets ascribe 4-10% of atmospheric CH4 sinks to upland soils and assume that soils are the sole surface for CH4 exchange between upland forests and the atmosphere. The prevailing dogma that upland forests are sinks of atmospheric CH4 was challenged a decade ago by large discrepancies in bottom-up versus top-down models of CH4 concentrations over upland forests that are still unexplained. Evidence of a novel abiotic mechanism for CH4 production from plant tissue is too small to explain the discrepancy. Alternative hypotheses for this observation have been proposed, but not tested. Here we demonstrate that CH4 is emitted from the stems of dominant tree species in an upland forest. Tree emissions occur throughout the growing season while soils adjacent to the trees are consuming CH4, challenging the concept that forests are uniform sinks of CH4. Scaling by stem surface area showed the forest to be a net CH4 source during a wet sample in June and a reduced CH4 sink by 5% annually. High frequency measurements revealed diurnal cycling in the rate of CH4 emissions, pointing to soils as the CH4 source and transpiration as the most likely pathway for CH4 transport. We propose the forests are smaller CH4 sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements.

  17. On the complexity of Nash dynamics and Sink Equilibria

    CERN Document Server

    Mirrokni, Vahab

    2009-01-01

    Studying Nash dynamics is an important approach for analyzing the outcome of games with repeated selfish behavior of self-interested agents. Sink equilibria has been introduced by Goemans, Mirrokni, and Vetta for studying social cost on Nash dynamics over pure strategies in games. However, they do not address the complexity of sink equilibria in these games. Recently, Fabrikant and Papadimitriou initiated the study of the complexity of Nash dynamics in two classes of games. In order to completely understand the complexity of Nash dynamics in a variety of games, we study the following three questions for various games: (i) given a state in game, can we verify if this state is in a sink equilibrium or not? (ii) given an instance of a game, can we verify if there exists any sink equilibrium other than pure Nash equilibria? and (iii) given an instance of a game, can we verify if there exists a pure Nash equilibrium (i.e, a sink equilibrium with one state)? In this paper, we almost answer all of the above question...

  18. Phase Change Material Heat Sink for an ISS Flight Experiment

    Science.gov (United States)

    Quinn, Gregory; Stieber, Jesse; Sheth, Rubik; Ahlstrom, Thomas

    2015-01-01

    A flight experiment is being constructed to utilize the persistent microgravity environment of the International Space Station (ISS) to prove out operation of a microgravity compatible phase change material (PCM) heat sink. A PCM heat sink can help to reduce the overall mass and volume of future exploration spacecraft thermal control systems (TCS). The program is characterizing a new PCM heat sink that incorporates a novel phase management approach to prevent high pressures and structural deformation that often occur with PCM heat sinks undergoing cyclic operation in microgravity. The PCM unit was made using brazed aluminum construction with paraffin wax as the fusible material. It is designed to be installed into a propylene glycol and water cooling loop, with scaling consistent with the conceptual designs for the Orion Multipurpose Crew Vehicle. This paper reports on the construction of the PCM heat sink and on initial ground test results conducted at UTC Aerospace Systems prior to delivery to NASA. The prototype will be tested later on the ground and in orbit via a self-contained experiment package developed by NASA Johnson Space Center to operate in an ISS EXPRESS rack.

  19. Substantial global carbon uptake by cement carbonation

    Science.gov (United States)

    Xi, Fengming; Davis, Steven J.; Ciais, Philippe; Crawford-Brown, Douglas; Guan, Dabo; Pade, Claus; Shi, Tiemao; Syddall, Mark; Lv, Jie; Ji, Lanzhu; Bing, Longfei; Wang, Jiaoyue; Wei, Wei; Yang, Keun-Hyeok; Lagerblad, Björn; Galan, Isabel; Andrade, Carmen; Zhang, Ying; Liu, Zhu

    2016-12-01

    Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process--carbonation--has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO2, increasing from 0.10 GtC yr-1 in 1998 to 0.25 GtC yr-1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

  20. A Comprehensive Study of Data Collection Schemes Using Mobile Sinks in Wireless Sensor Networks

    OpenAIRE

    Khan, Abdul Waheed; Abdullah, Abdul Hanan; Anisi, Mohammad Hossein; Bangash, Javed Iqbal

    2014-01-01

    Recently sink mobility has been exploited in numerous schemes to prolong the lifetime of wireless sensor networks (WSNs). Contrary to traditional WSNs where sensory data from sensor field is ultimately sent to a static sink, mobile sink-based approaches alleviate energy-holes issues thereby facilitating balanced energy consumption among nodes. In mobility scenarios, nodes need to keep track of the latest location of mobile sinks for data delivery. However, frequent propagation of sink topolog...

  1. Review of tribological sinks in six major industries

    Energy Technology Data Exchange (ETDEWEB)

    Imhoff, C.H.; Brown, D.R.; Hane, G.J.; Hutchinson, R.A.; Erickson, R.; Merriman, T.; Gruber, T.; Barber, S.

    1985-09-01

    Friction and material wear occur throughout all industries and are involved in many processes within each industry. These conditions make assessing tribological activity overall in industry very complex and expensive. Therefore, a research strategy to obtain preliminary information on only the most significant industrial tribological sinks was defined. The industries examined were selected according to both the magnitude of overall energy consumption (particularly machine drive) and the known presence of significant tribological sinks. The six industries chosen are as follows: mining, agriculture, primary metals, chemicals/refining, food, and pulp and paper. They were reviewed to identify and characterize the major tribology sinks. It was concluded that wear losses are greater than friction losses, and that reducing wear rates would improve industrial productivity.

  2. Effect of environmental factors (wave exposure and depth) and anthropogenic pressure in the C sink capacity of Posidonia oceanica meadows

    KAUST Repository

    Mazarrasa, Inés

    2017-03-20

    Seagrass are among the most important natural carbon sinks on Earth with Posidonia oceanica (Mediterranean Sea) considered as the most relevant species. Yet, the number of direct measurements of organic carbon burial rates in P. oceanica is still scarce and the effect of local environmental factors remains largely unexplored. In addition, P. oceanica meadows are declining due to the increase in anthropogenic pressure in coastal areas during the last century. The aim of this study is to assess the recent carbon sink capacity of P. oceanica and particularly the effect of human pressure and two environmental factors, water depth and exposure to wave energy (based on a fetch index), on the carbon burial rate since 1900. We conducted an extensive survey of sediment cores in meadows distributed across a gradient of depth, fetch, and human pressure around The Balearic Islands. Sediment and carbon accumulation rates were obtained from 210Pb concentrations profiles. Top-30 centimeters carbon stocks (6.1 ± 1.4 kg C m−2) and burial rates (26 ± 6 g C m−2 yr1) varied up to fivefold across meadows. No significant effect of water depth in carbon burial rates was observed. Although fetch was significantly correlated with sediment mean grain size, confirming the effect of wave exposure in the patterns of sedimentation, fetch alone could not explain the differences in carbon burial rates among the meadows examined. Human pressure affected carbon burial rates, leading to increased rates since the onset of the rise in anthropogenic pressure, particularly so in sheltered meadows supporting high human pressure.

  3. Mechanisms and rates of bacterial colonization of sinking aggregates

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Grossart, H.P.; Ploug, H.;

    2002-01-01

    (0 to 2 s(-1)). The rates at which these bacteria colonized artificial aggregates (stationary and sinking) largely agreed with model predictions. We report several findings. (i) Motile bacteria rapidly colonize aggregates, whereas nonmotile bacteria do not. 00 Flow enhances colonization rates. (iii...... frequency, and turn angles) and the hydrodynamic environment (stationary versus sinking aggregates). We then experimentally tested the models with 10 strains of bacteria isolated from marine particles: two strains were nonmotile; the rest were swimming at 20 to 60 mum s(-1) with different tumbling frequency...

  4. Droplet pattern and condensation gradient around a humidity sink

    OpenAIRE

    González-Viñas, W; Beysens, D. A.; Narhe, R.D. (Ramchandra D.); Guadarrama-Cetina, J.

    2014-01-01

    We describe the evolution of a water drop saturated with NaCl and the growth of pure water droplets in a breath figure pattern (BF) condensing around it. This salty drop acts as a humidity sink, inhibiting the BF inside a ring at a distance r=δ from the sink center and slowing down BF growth outside the ring. The initial salty drop is taken either from a salt-saturated solution (type I experiment) or by placing an NaCl crystal on the substrate (type II experiment). The results are similar, pr...

  5. TEM Pump With External Heat Source And Sink

    Science.gov (United States)

    Nesmith, Bill J.

    1991-01-01

    Proposed thermoelectric/electromagnetic (TEM) pump driven by external source of heat and by two or more heat pipe radiator heat sink(s). Thermoelectrics generate electrical current to circulate liquid metal in secondary loop of two-fluid-loop system. Intended for use with space and terrestrial dual loop liquid metal nuclear reactors. Applications include spacecraft on long missions or terrestrial beacons or scientific instruments having to operate in remote areas for long times. Design modified to include multiple radiators, converters, and ducts, as dictated by particular application.

  6. Microbial community structure in three deep-sea carbonate crusts

    NARCIS (Netherlands)

    Heijs, S. K.; Aloisi, G.; Bouloubassi, I.; Pancost, R. D.; Pierre, C.; Damste, J. S. Sinninghe; Gottschal, J. C.; van Elsas, J. D.; Forney, L. J.

    2006-01-01

    Carbonate crusts in marine environments can act as sinks for carbon dioxide. Therefore, understanding carbonate crust formation could be important for understanding global warming. In the present study, the microbial communities of three carbonate crust samples from deep-sea mud volcanoes in the eas

  7. Sinking blind shaft G272 at the West colliery of RAG by means of an innovative sinking technology

    Energy Technology Data Exchange (ETDEWEB)

    Stenmans, Karl-Heinz [RAG Aktiengesellschaft, Kamp-Lintfort (Germany). West Colliery; Reith, Dietmar [Induberg Produktionsgesellschaft GmbH, Ahlen (Germany)

    2008-08-21

    With the shaft jumbo an innovative sinking technology is being used for the first time in the German coal mining industry. The drilling equipment originating from French shaft sinking was modified to meet the requirements of operation at the West colliery. The equipment is to be used to drill the shot holes and bolt holes for sinking a 535 m blind shaft. The first 50 m have already been sunk, and provides an opportunity to report on the experience so far acquired and describe the further procedure. The work on the site was considerably exacerbated by the inflow of large quantities of water, the impact of which was increased by the upward ventilation in the advance borehole. The new shaft is highly important in the development of the reserves in the Girondelle 5 seam. The specialist mining company Induberg was qualified for this task not least of all because of its references in the field of drivage of mine workings. (orig.)

  8. Mycorrhizal mediation of soil organic carbon decomposition under elevated atmospheric carbon dioxide

    Science.gov (United States)

    Significant effort in global change research has recently been directed towards assessing the potential of soil as a carbon sink under future atmospheric carbon dioxide scenarios. Attention has focused on the impact of elevated carbon dioxide on plant interactions with mycorrhizae, a symbiotic soil...

  9. LiDAR-derived carbon estimates in encroaching juniper woodlands

    Science.gov (United States)

    Woody encroachment is thought to contribute significantly to the global carbon (C) sink. The global- and continental-scale estimates of this contribution, however, have large uncertainties. The woody encroachment contribution to the C sink needs to be estimated at regional and local scales to addres...

  10. Optimization of Heat-Sink Cooling Structure in EAST with Hydraulic Expansion Technique%Optimization of Heat-Sink Cooling Structure in EAST with Hydraulic Expansion Technique

    Institute of Scientific and Technical Information of China (English)

    许铁军; 黄生洪; 谢韩; 宋云涛; 张平; 戢翔; 高大明

    2011-01-01

    Considering utilization of the original chromium-bronze material, two processing techniques including hydraulic expansion and high temperature vacuum welding were proposed for the optimization of heat-sink structure in EAST. The heat transfer performance of heat-sink with or without cooling tube was calculated and different types of connection between tube and heat-sink were compared by conducting a special test. It is shown from numerical analysis that the diameter of heat-sink channel can be reduced from 12 mm to 10 mm. Compared with the original sample, the thermal contact resistance between tube and heat-sink for welding sample can reduce the heat transfer performance by 10%, while by 20% for the hydraulic expansion sample. However, the welding technique is more complicated and expensive than hydraulic expansion technique. Both the processing technique and the heat transfer performance of heat-sink prototype should be further considered for the optimization of heat-sink structure in EAST.

  11. Optimal sink placement in backbone assisted wireless sensor networks

    Directory of Open Access Journals (Sweden)

    I. Snigdh

    2016-07-01

    Full Text Available This article proposes a scheme for selecting the best site for sink placement in WSN applications employing backbone assisted communications. By placing the sink at a specific position, energy scavenging and delay constraints can effectively be controlled. In contrast to the conventional scheme for base station placement at the geographical centre or random placement at the end of the region of interest, the proposed scheme places the base station at either the graph theoretical centre or centroid of the backbone connecting nodes in the region of interest. This strategy shows a considerable reduction in the total number of hops that each packet needs to travel to reach the sink. The proposed scheme is applied on all the families of graphs prevalent in backbone assisted sensor networks to confirm the performance consistency and improvement in network parameters of the communication backbone measured in terms of delay, the carried load and the total energy consumption, eventually affected by the average number of hops for the message to reach the sink.

  12. Coulomb sink effect on coarsening of metal nanostructures on surfaces

    Institute of Scientific and Technical Information of China (English)

    Yong HAN; Feng LIU

    2008-01-01

    We discuss Coulomb effects on the coarsening of metal nanostructures on surfaces. We have proposed a new concept of a "Coulomb sink" [Phys. Rev. Lett., 2004, 93: 106102] to elucidate the effect of Coulomb charging on the coarsening of metal mesas grown on semiconductor surfaces. A charged mesa, due to its reduced chemical potential, acts as a Coulomb sink and grows at the expense of neighboring neu-tral mesas. The Coulomb sink provides a potentially useful method for the controlled fabrication of metal nanostructures. In this article, we will describe in detail the proposed physical models, which can explain qualitatively the most salient fea-tures of coarsening of charged Pb mesas on the Si(111) sur-face, as observed by scanning tunneling microscopy (STM). We will also describe a method of precisely fabricating large-scale nanocrystals with well-defined shape and size. By using the Coulomb sink effect, the artificial center-full-hol-lowed or half-hollowed nanowells can be created.

  13. Development of an operations evaluation system for sinking EDM

    NARCIS (Netherlands)

    Lauwers, B.; Oosterling, J.A.J.; Vanderauwera, W.

    2010-01-01

    This paper describes the development and validation of an operations evaluation system for sinking EDM operations. Based on a given workpiece geometry (e.g. mould), regions to be EDM'ed are automatically indentified. For a given electrode configuration, consisting of one or more regions, EDM machini

  14. Seismicity in Romania--evidence for the sinking lithosphere.

    Science.gov (United States)

    Roman, C

    1970-12-19

    The revision of Romanian earthquakes shows a distribution suggesting a sinking lithosphere under the Carpathian arc. Thermal and gravitational anomalies, as well as petrological and tectonic features, provide further evidence on the cause and character of intermediate earthquakes of Romania. This is consistent with the theory of plate tectonics in south-east Europe.

  15. EVALUATION OF SINK EFFECTS ON VOCS FROM A LATEX PAINT

    Science.gov (United States)

    The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and texanol. These oxygenated compounds rep...

  16. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However...

  17. Sinking failure of scour protection at wind turbine foundation

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Nielsen, Anders W.

    2013-01-01

    This paper summarises the results of an experimental study on scour protection around offshore wind turbine foundations, with special emphasis on the sinking failure of the scour protection work in Horns Rev 1 offshore wind farm (Denmark). The paper reviews previous results obtained by the author...

  18. A simple method to convert sink particles into stars

    CERN Document Server

    Sormani, Mattia C; Klessen, Ralf S; Glover, Simon C O

    2016-01-01

    Hydrodynamical simulations of star formation often do not possess the dynamic range needed to fully resolve the build-up of individual stars and star clusters, and thus have to resort to subgrid models. A popular way to do this is by introducing Lagrangian sink particles, which replace contracting high density regions at the point where the resolution limit is reached. A common problem then is how to assign fundamental stellar properties to sink particles, such as the distribution of stellar masses. We present a new and simple statistical method to assign stellar contents to sink particles. Once the stellar content is specified, it can be used to determine a sink particle's radiative output, supernovae rate or other feedback parameters that may be required in the calculations. Advantages of our method are (i) it is simple to implement, (ii) it guarantees that the obtained stellar populations are good samples of the initial mass function, (iii) it can easily deal with infalling mass accreted at later times, an...

  19. Comparison between treatment of kitchen-sink wastewater and a mixture of kitchen-sink and washing-machine wastewaters.

    Science.gov (United States)

    Huelgas, A; Nakajima, M; Nagata, H; Funamizu, N

    2009-01-01

    In this paper, a submerged membrane bioreactor was used to treat 'higher-load' grey water: (a) kitchen-sink wastewater only, and (b) a mixture of kitchen-sink wastewater and washing-machine wastewater. For each type of wastewater, three systems operated at different hydraulic retention times (HRTs) were investigated. In the mixture of kitchen-sink wastewater and washing-machine wastewater, the reactor with a short HRT of four hours was stopped due to foaming. It has been observed that for both types of wastewater, an HRT of eight hours or longer can be used for the treatment. However, it has been observed that a higher COD in the permeate of the mixture can be obtained compared with that of the kitchen-sink wastewater only. This indicated that washing-machine wastewater has some component that is not easily biodegradable. The total linear akylbenzene sulfonate (LAS) removal was > 99% even at a concentration of 10-23 mg 1(-1).

  20. Intracellular nitrate of marine diatoms as a driver of anaerobic nitrogen cycling in sinking aggregates

    DEFF Research Database (Denmark)

    Kamp, Anja; Stief, Peter; Bristow, Laura A.;

    2016-01-01

    Diatom-bacteria aggregates are key for the vertical transport of organic carbon in the ocean. Sinking aggregates also represent pelagic microniches with intensified microbial activity, oxygen depletion in the center, and anaerobic nitrogen cycling. Since some of the aggregate-forming diatom species...... store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom......-bacteria aggregates. Stable 15N isotope incubations under dark and anoxic conditions revealed that axenic S. marinoi is able to reduce intracellular nitrate to ammonium that is immediately excreted by the cells. When exposed to a light:dark cycle and oxic conditions, S. marinoi stored nitrate intracellularly...

  1. Moving multiple sinks through wireless sensor networks for lifetime maximization.

    Energy Technology Data Exchange (ETDEWEB)

    Petrioli, Chiara (Universita di Roma); Carosi, Alessio (Universita di Roma); Basagni, Stefano (Northeastern University); Phillips, Cynthia Ann

    2008-01-01

    Unattended sensor networks typically watch for some phenomena such as volcanic events, forest fires, pollution, or movements in animal populations. Sensors report to a collection point periodically or when they observe reportable events. When sensors are too far from the collection point to communicate directly, other sensors relay messages for them. If the collection point location is static, sensor nodes that are closer to the collection point relay far more messages than those on the periphery. Assuming all sensor nodes have roughly the same capabilities, those with high relay burden experience battery failure much faster than the rest of the network. However, since their death disconnects the live nodes from the collection point, the whole network is then dead. We consider the problem of moving a set of collectors (sinks) through a wireless sensor network to balance the energy used for relaying messages, maximizing the lifetime of the network. We show how to compute an upper bound on the lifetime for any instance using linear and integer programming. We present a centralized heuristic that produces sink movement schedules that produce network lifetimes within 1.4% of the upper bound for realistic settings. We also present a distributed heuristic that produces lifetimes at most 25:3% below the upper bound. More specifically, we formulate a linear program (LP) that is a relaxation of the scheduling problem. The variables are naturally continuous, but the LP relaxes some constraints. The LP has an exponential number of constraints, but we can satisfy them all by enforcing only a polynomial number using a separation algorithm. This separation algorithm is a p-median facility location problem, which we can solve efficiently in practice for huge instances using integer programming technology. This LP selects a set of good sensor configurations. Given the solution to the LP, we can find a feasible schedule by selecting a subset of these configurations, ordering them

  2. Reburial of fossil organic carbon in marine sediments

    OpenAIRE

    2004-01-01

    Marine sediments act as the ultimate sink for organic carbon, sequestering otherwise rapidly cycling carbon for geologic timescales. Sedimentary organic carbon burial appears to be controlled by oxygen exposure time in situ, and much research has focused on understanding the mechanisms of preservation of organic carbon. In this context, combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. How...

  3. 78 FR 21596 - Drawn Stainless Steel Sinks From the People's Republic of China: Countervailing Duty Order

    Science.gov (United States)

    2013-04-11

    ... welding operation to form one unit are covered by the scope of the order. Drawn stainless steel sinks are... may sometimes be referred to as ``zero radius'' or ``near zero radius'' sinks. The products covered...

  4. Towards a more realistic sink particle algorithm for the RAMSES code

    CERN Document Server

    Bleuler, Andreas

    2014-01-01

    We present a new sink particle algorithm developed for the Adaptive Mesh Refinement code RAMSES. Our main addition is the use of a clump finder to identify density peaks and their associated regions (the peak patches). This allows us to unambiguously define a discrete set of dense molecular cores as potential sites for sink particle formation. Furthermore, we develop a new scheme to decide if the gas in which a sink could potentially form, is indeed gravitationally bound and rapidly collapsing. This is achieved using a general integral form of the virial theorem, where we use the curvature in the gravitational potential to correctly account for the background potential. We detail all the necessary steps to follow the evolution of sink particles in turbulent molecular cloud simulations, such as sink production, their trajectory integration, sink merging and finally the gas accretion rate onto an existing sink. We compare our new recipe for sink formation to other popular implementations. Statistical properties...

  5. Sinking velocity of particulate radiocesium in the northwestern North Pacific

    Science.gov (United States)

    Honda, Makio C.; Kawakami, Hajime

    2014-06-01

    Sinking particles (SP) were collected by time series sediment traps at two depths in the northwestern Pacific before and after the Fukushima Daiichi Nuclear Power Plant accident, and accident-derived particulate radiocesium was measured. Radiocesium (137Cs) was first detected at 500 m (4810 m) about 2 weeks (1 month) after the accident. 137Cs of SP collected over 1 year revealed that the time lag between two depths was larger than that for the first 137Cs detection (about 2 weeks). We estimated the transient sinking velocity (SV) from the cumulative temporal 137Cs flux and the time lags at the two depths. Although the SV of SP collected in very early period was large, the estimated SV of most particulate 137Cs (about 80%) was about 50 m d-1. Based on comparison of 137Cs concentration in total SP with that in SP without organic materials, we suspect that most of the 137Cs was likely incorporated into aluminosilicates.

  6. Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, Upper Yangtze, China from 1975 to 2000

    Science.gov (United States)

    Zhao, Shuqing

    2010-01-01

    Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

  7. Pristine mangrove creek waters are a sink of nitrous oxide

    Science.gov (United States)

    Maher, Damien T.; Sippo, James Z.; Tait, Douglas R.; Holloway, Ceylena; Santos, Isaac R.

    2016-05-01

    Nitrous oxide (N2O) is an important greenhouse gas, but large uncertainties remain in global budgets. Mangroves are thought to be a source of N2O to the atmosphere in spite of the limited available data. Here we report high resolution time series observations in pristine Australian mangroves along a broad latitudinal gradient to assess the potential role of mangroves in global N2O budgets. Surprisingly, five out of six creeks were under-saturated in dissolved N2O, demonstrating mangrove creek waters were a sink for atmospheric N2O. Air-water flux estimates showed an uptake of 1.52 ± 0.17 μmol m-2 d-1, while an independent mass balance revealed an average sink of 1.05 ± 0.59 μmol m-2 d-1. If these results can be upscaled to the global mangrove area, the N2O sink (~2.0 × 108 mol yr-1) would offset ~6% of the estimated global riverine N2O source. Our observations contrast previous estimates based on soil fluxes or mangrove waters influenced by upstream freshwater inputs. We suggest that the lack of available nitrogen in pristine mangroves favours N2O consumption. Widespread and growing coastal eutrophication may change mangrove waters from a sink to a source of N2O to the atmosphere, representing a positive feedback to climate change.

  8. Sinking of armour layer around a vertical cylinder exposed to waves and current

    DEFF Research Database (Denmark)

    Nielsen, Anders Wedel; Probst, Thomas; Petersen, Thor Ugelvig;

    2015-01-01

    The mechanisms of the sinking of a scour protection adjacent to a monopile are described in this paper, together with the determination of the equilibrium sinking depth in various wave and combined wave and current conditions based on physical model tests.Sinking of the rocks may ultimately lead...

  9. Sink strength as a determinant of dry matter partitioning in the whole plant

    NARCIS (Netherlands)

    Marcelis, L.F.M.

    1996-01-01

    Dry matter partitioning is the end result of the flow of assimilates from source organs via a transport path to the sink organs. The dry matter partitioning among the sinks of a plant is primarily regulated by the sinks themselves. The effect of source strength on dry matter partitioning is often no

  10. Changes of the oceanic CO{sub 2} sink in the Eastern Indian sector of the Southern Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Breviere, Emily; Metzl, Nicolas; Poisson, Alain [Univ. Pierre et Marie Curie, Paris (France). Lab. d' Oceanographie et du Climat (LOCEAN/IPSL); Tilbrook, Bronte [CSIRO Marine and Atmospheric Research and Antarctic Climate and Ecosystems CRC, Hobart (Australia)

    2006-11-15

    Changes in the carbon dioxide fugacity (fCO{sub 2}) and air-sea CO{sub 2} flux observed in the Southern Ocean, south of Tasmania were analysed and compared for two different years: 1996/1997 and 2002/2003.The CO{sub 2} flux showed large and contrasting interannual changes in the permanent open ocean zone (POOZ, 53-61oS) between the 2 yr where the oceanic CO{sub 2} sink increased from about -0.3 mmol/m{sup 2}/d in February 1997 to -20.6 mmol/m{sup 2}/d in February 2003. The strong sink in February 2003 was associated with increased phytoplankton biomass in this High-Nutrient, Low-Chlorophyll (HNLC) region. Three hypotheses that may have influenced the biomass and fCO{sub 2} changes in the POOZ were investigated: sea surface temperature (SST) and El Nino/Southern Oscillation (ENSO) event, total stratospheric ozone column and ultraviolet (UV) radiation, and atmospheric dust inputs. The strong CO{sub 2} sink in 2003 in the POOZ cannot be explained by the observed changes in SST or UV, but would be qualitatively consistent with the presence of episodic atmospheric dust inputs.

  11. Rapid prediction of floating and sinking components of raw coal

    Institute of Scientific and Technical Information of China (English)

    Wang Guanghui; Kuang Yali; Wang Zhangguo; Ji Li; Wang Ying

    2012-01-01

    A model that rapidly predicts the density components of raw coal is described.It is based on a three-grade fast float/sink test.The recent comprehensive monthly floating and sinking data are used for comparison.The predicted data are used to draw washability curves and to provide a rapid evaluation of the effect from heavy medium induced separation.Thirty-one production shifts worth of fast float/sink data and the corresponding quick ash data are used to verify the model.The results show a small error with an arithmetic average of 0.53 and an absolute average error of 1.50.This indicates that this model has high precision.The theoretical yield from the washability curves is 76.47% for the monthly comprehensive data and 81.31% using the model data.This is for a desired cleaned coal ash of 9%.The relative error between these two is 6.33%,which is small and indicates that the predicted data can be used to rapidly evaluate the separation effect of gravity separation equipment.

  12. Sinking of spherical slablets through a non-Newtonian mantle

    Science.gov (United States)

    Crameri, Fabio; Stegman, Dave; Petersen, Robert; Tackley, Paul

    2014-05-01

    The dominant driving force for plate tectonics is slab pull, in which sinking slabs pull the trailing plate. Forward plate velocities are typically similar in magnitude (7 cm/yr) as estimates for sinking velocities of slabs through the upper mantle. However, these estimates are based on data for slabs that are coherent into the transition zone as well as models that considered the upper mantle to be entirely Newtonian. Dislocation creep in the upper mantle can strongly influence mantle flow, and is likely activated for flow around vertically sinking slabs in the uppermost mantle. Thus, it is possible that in some scenarios, a non-Newtonian mantle will have an influence on plate motions but it is unclear to what degree. To address this question, we investigate how the non-Newtonian rheology modifies the sinking velocities of slablets (spherical, negatively buoyant and highly viscous blobs). The model set-up is similar to a Stokes sphere sinking, but is in 2-D cartesian with temperature-and stress-dependent rheology. For these numerical models, we use the Stag-YY code (e.g., Tackley 2008) and apply a pseudo-free surface using the 'sticky-air' approach (Matsumoto and Tomoda 1983; Schmeling et al, 2008, Crameri et al., 2012). The sinking blob is both highly viscous and compositionally dense, but is the same temperature as the background fluid which eliminates thermal diffusion and associated variations in thermal buoyancy. The model domain is 2x1 or 4x1 and allows enough distance to the sidewalls so that sinking velocities are not influenced by the boundary conditions. We compare our results with those previously obtained for salt diapirs rising through a power-law rheology mantle/crust (Weinberg, 1993; Weinberg and Podladchikov, 1994), which provided both numerical and analytic results. Previous results indicate a speed-up of an order of magnitude is possible. Finally, we then extend the models and analysis to mantle convection systems that include for single

  13. Boreal forests can have a remarkable role in reducing greenhouse gas emissions locally: Land use-related and anthropogenic greenhouse gas emissions and sinks at the municipal level

    Energy Technology Data Exchange (ETDEWEB)

    Vanhala, Pekka, E-mail: pekka.vanhala@ymparisto.fi [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Bergström, Irina [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Haaspuro, Tiina [University of Helsinki, Department of Environmental Sciences, P.O. Box 65, Viikinkaari 1, 00014 Helsinki (Finland); Kortelainen, Pirkko; Holmberg, Maria; Forsius, Martin [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland)

    2016-07-01

    Ecosystem services have become an important concept in policy-making. Carbon (C) sequestration into ecosystems is a significant ecosystem service, whereas C losses can be considered as an ecosystem disservice. Municipalities are in a position to make decisions that affect local emissions and therefore are important when considering greenhouse gas (GHG) mitigation. Integrated estimations of fluxes at a regional level help local authorities to develop land use policies for minimising GHG emissions and maximising C sinks. In this study, the Finnish national GHG accounting system is modified and applied at the municipal level by combining emissions and sinks from agricultural land, forest areas, water bodies and mires (land use-related GHG emissions) with emissions from activities such as energy production and traffic (anthropogenic GHG emissions) into the LUONNIKAS calculation tool. The study area consists of 14 municipalities within the Vanajavesi catchment area located in Southern Finland. In these municipalities, croplands, peat extraction sites, water bodies and undrained mires are emission sources, whereas forests are large carbon sinks that turn the land use-related GHG budget negative, resulting in C sequestration into the ecosystem. The annual land use-related sink in the study area was 78 t CO{sub 2} eq km{sup −2} and 2.8 t CO{sub 2} eq per capita. Annual anthropogenic GHG emissions from the area amounted to 250 t CO{sub 2} eq km{sup −2} and 9.2 t CO{sub 2} eq per capita. Since forests are a significant carbon sink and the efficiency of this sink is heavily affected by forest management practices, forest management policy is a key contributing factor for mitigating municipal GHG emissions. - Highlights: • The significance of natural landscapes in the regional C budgets is shown. • Boreal forests can be remarkable C sinks enabling net C sequestration in ecosystems. • The large area of forest may compensate for all C emissions in the municipality.

  14. The Biological carbon pump in the North Atlantic

    DEFF Research Database (Denmark)

    Sanders, Richard; Henson, Stephanie A.; Koski, Marja

    2014-01-01

    Mediated principally by the sinking of organic rich particles from the upper ocean, the Biological Carbon Pump (BCP) is a significant component of the global carbon cycle. It transfers roughly 11 Gt C yr−1 into the ocean’s interior and maintains atmospheric carbon dioxide at significantly lower l...

  15. Development of a sink-source interaction model for the growth of short-rotation coppice willow and in silico exploration of genotype×environment effects.

    Science.gov (United States)

    Cerasuolo, M; Richter, G M; Richard, B; Cunniff, J; Girbau, S; Shield, I; Purdy, S; Karp, A

    2016-02-01

    Identifying key performance traits is essential for elucidating crop growth processes and breeding. In Salix spp., genotypic diversity is being exploited to tailor new varieties to overcome environmental yield constraints. Process-based models can assist these efforts by identifying key parameters of yield formation for different genotype×environment (G×E) combinations. Here, four commercial willow varieties grown in contrasting environments (west and south-east UK) were intensively sampled for growth traits over two 2-year rotations. A sink-source interaction model was developed to parameterize the balance of source (carbon capture/mobilization) and sink formation (morphogenesis, carbon allocation) during growth. Global sensitivity analysis consistently identified day length for the onset of stem elongation as most important factor for yield formation, followed by various 'sink>source' controlling parameters. In coastal climates, the chilling control of budburst ranked higher compared with the more eastern climate. Sensitivity to drought, including canopy size and rooting depth, was potentially growth limiting in the south-east and west of the UK. Potential yields increased from the first to the second rotation, but less so for broad- than for narrow-leaved varieties (20 and 47%, respectively), which had established less well initially (-19%). The establishment was confounded by drought during the first rotation, affecting broad- more than narrow-leaved canopy phenotypes (-29%). The analysis emphasized quantum efficiency at low light intensity as key to assimilation; however, on average, sink parameters were more important than source parameters. The G×E pairings described with this new process model will help to identify parameters of sink-source control for future willow breeding.

  16. Carbon Farming as a Carbon Negative Technology

    Science.gov (United States)

    Anderson, C.; Laird, D.; Hayes, D. J.

    2015-12-01

    Carbon farms have a pivotal role in national and international efforts to mitigate and adapt to climate change. A carbon farm in its broadest sense is one that reduces greenhouse gas (GHG) emissions or captures and holds carbon in vegetation and soils. Their capacity to remove carbon from the air and store it safely and permanently, while providing additional human and ecosystem benefits, means they could contribute significantly to national efforts to stabilize or reduce GHGs. We examine carbon farms in the context of corn and soybean production agriculture. We illustrate, using Iowa data but with relevance across United States corn and soybean production, the potential for carbon farms to reduce human GHG emissions and sequester carbon permanently at a rate that has meaningful impact on global greenhouse gas concentration. Carbon has been viewed as a next generation cash crop in Iowa for over a decade. The carbon farm perspective, however, goes beyond carbon as cash crop to make carbon the center of an entire farm enterprise. The transformation is possible through slight adjustment crop practices mixed with advances in technology to sequester carbon through biochar. We examine carbon balance of Iowa agriculture given only the combination of slight reduction in fertilizer and sequestration by biochar. We find the following. Iowa carbon farms could turn Iowa agriculture into a carbon sink. The estimated range of GHG reduction by statewide implementation of carbon farms is 19.46 to 90.27 MMt CO2-equivalent (CO2-e), while the current agricultural CO2-e emission estimate is 35.38 MMt CO2-e. Iowa carbon farm GHG reduction would exceed Iowa GHG reduction by wind energy (8.7 MMt CO2-e) and could exceed combined reductions from wind energy and corn grain ethanol (10.7 MMt CO2-e; 19.4 MMt CO2-e combined). In fact, Iowa carbon farms alone could exceed GHG reduction from national corn grain ethanol production (39.6 MMt CO2-e). A carbon price accessible to agricultural

  17. Seagrass meadows as a globally significant carbonate reservoir

    OpenAIRE

    I. Mazarrasa; N. Marbà; Lovelock, C.E.; SERRANO, O; P. S. Lavery; J. W. Fourqurean; H. Kennedy; Mateo, M.A.; D. Krause-Jensen; A. D. L. Steven; Duarte, C. M.

    2015-01-01

    There has been a growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the organic carbon (POC) stocks and accumulation rates and ignored the inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and...

  18. Seagrass meadows as a globally significant carbonate reservoir

    OpenAIRE

    I. Mazarrasa; N. Marbà; Lovelock, C.E.; SERRANO, O; P. S. Lavery; J. W. Fourqurean; H. Kennedy; Mateo, M.A.; D. Krause-Jensen; A. D. L. Steven; Duarte, C. M.

    2015-01-01

    There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and be...

  19. Sinking Particle Flux in the Sea Ice Zone of the Amundsen Shelf, Antarctica

    Science.gov (United States)

    Kim, M.; Hwang, J.; Kim, H. J.; Kim, D.; Ducklow, H. W.; Lee, S. H.; Yang, E. J.; Lee, S.

    2014-12-01

    We have examined the flux, compositions of biogenic components, and isotopic values of sinking particles collected by a sediment trap deployed in the sea ice zone (SIZ) of the Amundsen Sea from January 2011 for one year. Major portion of the particle flux occurred during the austral summer in January and February when sea ice concentration was reduced to below 60 %. Biogenic components, dominated by opal, accounted for over 75 % during this high flux period. The dominant source of sinking particles shifted from diatoms to soft-tissued organisms, evidenced by high particulate organic carbon (POC) content (> 30 %) during the polar night. CaCO3 content and its contribution to total particle flux were low throughout the study period. Contribution of aged POC likely supplied from sediment resuspension was considerable only from October to December, evidenced by low radiocarbon content and relatively high (30-50 %) content of the non-biogenic component. When compared to POC flux inside the Amundsen Sea polynya obtained by the US Amundsen Sea Polynya International Research Expedition (ASPIRE), the POC flux integrated over the austral summer in the SIZ was virtually identical although maximum POC flux was about half that inside the Amundsen Sea polynya. This comparatively high POC flux in the SIZ may be caused by persistence of phytoplankton bloom for longer period and more efficient export of organic matter owing to the diatom-dominant plankton community. If this observation is a general phenomenon on the Amundsen shelf, the role of the SIZ compared to the polynyas need to be examined more carefully when trying to characterize the POC export in this region.

  20. How Reservoirs Alter DOM Amount and Composition: Sources, Sinks, and Transformations

    Science.gov (United States)

    Kraus, T. E.; Bergamaschi, B. A.; Hernes, P. J.; Doctor, D. H.; Kendall, C.; Losee, R. F.; Downing, B. D.

    2011-12-01

    Reservoirs are critical components of many water supply systems as they allow the storage of water when supply exceeds demand. However, during water storage biogeochemical processes can alter both the amount and composition of dissolved organic matter (DOM), which can in turn affect water quality. While the balance between production and loss determines whether a reservoir is a net sink or source of DOM, changes in chemical composition are also relevant as they affect DOM reactivity (e.g. persistence in the environment, removability during coagulation treatment, and potential to form toxic compounds during drinking water treatment). The composition of the DOM pool also provides information about the DOM sources and processing, which can inform reservoir management. We examined the concentration and composition of DOM in San Luis Reservoir (SLR), a large off-stream impoundment of the California State Water Project. We used an array of DOM chemical tracers including dissolved organic carbon (DOC) concentration, optical properties, isotopic composition, lignin phenol content, and structural groupings determined by 13C NMR. There were periods when the reservoir was i) a net source of DOM due to the predominance of algal production (summer), ii) a net sink due to the predominance of degradation (fall/winter), and iii) balanced between production and consumption (spring). Despite only moderate variation in bulk DOC concentration (3.0-3.6 mg C/L), substantial changes in DOM composition indicated that terrestrial-derived material entering the reservoir was being degraded and replaced by aquatic-derived DOM produced within the reservoir. Results suggest reservoirs have the potential to reduce DOM amount and reactivity via degradative processes, however, these benefits can be decreased or even negated by the production of algal-derived DOM.

  1. CVD Diamond Sink Application in High Power 3D MCMs

    Institute of Scientific and Technical Information of China (English)

    XIE Kuo-jun; JIANG Chang-shun; LI Cheng-yue

    2005-01-01

    As electronic packages become more compact, run at faster speeds and dissipate more heat, package designers need more effective thermal management materials. CVD diamond, because of its high thermal conductivity, low dielectric loss and its great mechanical strength, is an excellent material for three dimensional (3D) multichip modules (MCMs) in the next generation compact high speed computers and high power microwave components. In this paper, we have synthesized a large area freestanding diamond films and substrates, and polished diamond substrates, which make MCMs diamond film sink becomes a reality.

  2. Outreach and education with a concurrent movie "Sinking of Japan"

    Science.gov (United States)

    Yamaoka, K.; Tsuji, H.; Doi, K.

    2006-12-01

    In the summer of 2006, the Japanese movie 'Sinking of Japan (Nihon Chinbotsu)" was released as a remake of the original movie in 33 years ago. The movie, based on the very popular SF novel of the same title, shows human action in the helpless crisis of Japan that is rapidly sinking into sea. Unexpected acceleration of plate subduction and mantle convection cause rapid sinking of Japan, accompanying disastrous earthquakes, tsunamis and volcanic eruptions. Genial but eccentric scientist (Professor of Earthquake Research Institute (ERI), Univ. of 'Toto') with submersible pilots fights against the disaster to help the people in Japanese archipelago. We are asked to help to check the scientific aspect of the movie in creating it. We accepted their offer in the following reasons. The original novel and movie in 33 years ago was very popular and more than 400 copies of the book are sold and about 6.5 million people went to theaters to see the movie. Therefore, the new movie was easily expected to get a big hit and we will have a rare opportunity to get a public interest to earth science. During the first run of the movie we operated 'Q and A' for the earth science of 'Sinking of Japan' on the web site of Earthquake Research Institute (ERI), University of Tokyo. The web site is linked to the official site of the movie, and major Japanese newspapers wrote about the 'Q and A' as an interesting action of ERI. Due to the efficient advertisement, more than 200 questions are submitted and more than 70 answers are listed on the web. More than 800,000 hits are counted to the site, showing wide range of interest to this topic. About half of the questions are on the scientific and disaster aspect of the movie. Half of the rest are on real disasters such as earthquakes or volcanic eruptions. Questions to be answered are selected so as to attract much interest not only to earth science but to the story of the movie itself to keep fun for the readers. As the movie and 'Q and A' are

  3. Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden.

    Directory of Open Access Journals (Sweden)

    Niall P McNamara

    Full Text Available Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4. In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished.

  4. Developing Carbon Sequestration Forestry for Mitigating Climate Change: Practice and Management of Carbon Sequestration Forestry in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    By elaborating the functions and effects of forestry in mitigating climate change, introducing the concepts and significance of forest carbon sink, forestry carbon sequestration, and carbon sequestration forestry, and summarizing the practices of carbon sequestration forestry in China, the paper came up with the outline for strengthening the management of carbon sequestration forestry, i.e. implementing the Climate Change Forestry Action Plan, reinforcing the accounting and monitoring of national forest car...

  5. A comprehensive study of data collection schemes using mobile sinks in wireless sensor networks.

    Science.gov (United States)

    Khan, Abdul Waheed; Abdullah, Abdul Hanan; Anisi, Mohammad Hossein; Bangash, Javed Iqbal

    2014-02-05

    Recently sink mobility has been exploited in numerous schemes to prolong the lifetime of wireless sensor networks (WSNs). Contrary to traditional WSNs where sensory data from sensor field is ultimately sent to a static sink, mobile sink-based approaches alleviate energy-holes issues thereby facilitating balanced energy consumption among nodes. In mobility scenarios, nodes need to keep track of the latest location of mobile sinks for data delivery. However, frequent propagation of sink topological updates undermines the energy conservation goal and therefore should be controlled. Furthermore, controlled propagation of sinks' topological updates affects the performance of routing strategies thereby increasing data delivery latency and reducing packet delivery ratios. This paper presents a taxonomy of various data collection/dissemination schemes that exploit sink mobility. Based on how sink mobility is exploited in the sensor field, we classify existing schemes into three classes, namely path constrained, path unconstrained, and controlled sink mobility-based schemes. We also organize existing schemes based on their primary goals and provide a comparative study to aid readers in selecting the appropriate scheme in accordance with their particular intended applications and network dynamics. Finally, we conclude our discussion with the identification of some unresolved issues in pursuit of data delivery to a mobile sink.

  6. Source-Sink Relationship in Intersubspecific Hybrid Rice

    Institute of Scientific and Technical Information of China (English)

    LI Ji-hang; XIANG Xun-chao; HE Li-bin; LI Ping

    2006-01-01

    Three indica restorer lines (Mianhui 725, Shuhui 527, Shuhui 881), an American rice variety Lemont and a javanica rice variety Xiangdali were crossed with japonica Kitaake, and five F1 hybrids were obtained to study the photosynthetic and agronomic traits. The data on photosynthetic characteristics indicated that the net photosynthetic rate (Pn) of the five F1 hybrids was significantly higher than that of their parents (or one of them) under high photosynthetic flux density (PFD); while the overall performance of hybrids was better than their respective parents in apparent quantum yield (AQY), carboxylation efficiency (CE) and CO2compensation point (CCP). Moreover, the photosynthetic performance of the five F1 were different due to the variation in heredity and the typical indica-japonica hybrids, Mianhui 725/Kitaake and Shuhui 527/Kitaake, were better than the others on this aspect. The agronomic traits revealed that the five F1 exhibited different heterosis, with Shuhui 881/Kitaake the largest sink followed by Mianhui725/Kitaake, Shuhui 527/Kitaake, Lemont/Kitaake and Xiangdaii/Kitaake. The production potential of indica-japonica hybrids was higher than that of the other two hybrids, which was consistent with the performance of Pn. However, the superior trait of indica-japonica hybrids on sink size has not been fully turned into high yield because of abnormal seed setting. Therefore, attention should be paid to the proper genome coordination and appropriate genetic distance so as to achieve super high yielding.

  7. Analysis of microchannel heat sink performance using nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Reiyu; Huang, Guanming [Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung City 402 (China)

    2005-12-01

    In this study, silicon microchannel heat sink performance using nanofluids as coolants was analyzed. The nanofluid was a mixture of pure water and nanoscale Cu particles with various volume fractions. The heat transfer and friction coefficients required in the analysis were based on theoretical models and experimental correlations. In the theoretical model, nanofluid was treated as a single-phase fluid. In the experimental correlation, thermal dispersion due to particle random motion was included. The microchannel heat sink performances for two specific geometries, one with W{sub ch}=W{sub fin}=100 {mu}m and L{sub ch}=300 {mu}m, the other with W{sub ch}=W{sub fin}=57 {mu}m and L{sub ch}=365 {mu}m, were examined. Because of the increased thermal conductivity and thermal dispersion effects, it was found that the performances were greatly improved for these two specific geometries when nanofluids were used as the coolants. In addition to heat transfer enhancement, the existence of nanoparticles in the fluid did not produce extra pressure drop because of small particle size and low particle volume fraction. (author)

  8. Significant sink of ocean-eddy energy near western boundaries

    Science.gov (United States)

    Zhai, Xiaoming; Johnson, Helen L.; Marshall, David P.

    2010-09-01

    Ocean eddies generated through instability of the mean flow are a vital component of the energy budget of the global ocean. In equilibrium, the sources and sinks of eddy energy have to be balanced. However, where and how eddy energy is removed remains uncertain. Ocean eddies are observed to propagate westwards at speeds similar to the phase speeds of classical Rossby waves, but what happens to the eddies when they encounter the western boundary is unclear. Here we use a simple reduced-gravity model along with satellite altimetry data to show that the western boundary acts as a `graveyard' for the westward-propagating ocean eddies. We estimate a convergence of eddy energy near the western boundary of approximately 0.1-0.3TW, poleward of 10° in latitude. This energy is most probably scattered into high-wavenumber vertical modes, resulting in energy dissipation and diapycnal mixing. If confirmed, this eddy-energy sink will have important implications for the ocean circulation.

  9. CO2 Sink/Source in the Indonesian Seas

    KAUST Repository

    Kartadikaria, Aditya R.

    2015-04-01

    Two distinct CO2 sink/source characteristics appeared from the compiled observed data 1984-2013 in the tropical Indonesian seas. The western part persistently emits CO2 to the atmosphere, while the eastern is rather dynamic which emits and absorbs smaller amount of CO2 to and from atmosphere, respectively. The segregation is proximal to the virtual Wallace line, where in the continental shelf is located. Lower salinity and higher silicate condition in the western part influenced the higher pCO2 condition in Java Sea. Temperature is found to have a limited influence to control different characteristic in the west and east, but SST change of 2.0 0C during La Ninã condition effectively reduced the source amount of CO2 by 50% compared to Normal year condition. Yet, during La Ninã, higher wind speed increases CO2 flux twice compared to Normal year. In the continental shelf area where CO2 sink area is found, 29 years data showed that pCO2 trend is increasing ±0.6-3.8 μatm/year. From this study, the overall areas have a significant source of CO2 of approximately 10 - 24 μatm.

  10. Droplet pattern and condensation gradient around a humidity sink.

    Science.gov (United States)

    Guadarrama-Cetina, J; Narhe, R D; Beysens, D A; González-Viñas, W

    2014-01-01

    We describe the evolution of a water drop saturated with NaCl and the growth of pure water droplets in a breath figure pattern (BF) condensing around it. This salty drop acts as a humidity sink, inhibiting the BF inside a ring at a distance r=δ from the sink center and slowing down BF growth outside the ring. The initial salty drop is taken either from a salt-saturated solution (type I experiment) or by placing an NaCl crystal on the substrate (type II experiment). The results are similar, provided that the initial time for type II evolution is taken at the end of the crystal dissolution. The evolution of the salty drop radius R is deduced from the establishment of a three-dimensional hyperbolic concentration profile around the salty drop. This profile scales with r/δ. Accounting for the salt concentration decrease with salty drop growth, R is seen to grow as t5. In the region r>δ, water droplets nucleate and grow. The rate of evolution of the water droplets at constant r/δ can be used to determine the local water pressure. The corresponding data reasonably agree with a hyperbolic water vapor profile around the salty drop. These results can be applied to the growth of BF patterns to determine whether hyperbolic or linear water vapor profiles apply.

  11. An underestimated methane sink in Arctic mineral soils

    Science.gov (United States)

    Oh, Y.; Medvigy, D.; Stackhouse, B. T.; Lau, M.; Onstott, T. C.; Jørgensen, C. J.; Elberling, B.; Emmerton, C. A.; St Louis, V. L.; Moch, J.

    2015-12-01

    Atmospheric methane has more than doubled since the industrial revolution, yet the sources and sinks are still poorly constrained. Though soil methane oxidation is the largest terrestrial methane sink, it is inadequately represented in current models. We have conducted laboratory analysis of mineral cryosol soils from Axel Heiberg Island in the Canadian high arctic. Microcosm experiments were carried out under varying environmental conditions and used to parameterize methane oxidation models. One-meter long intact soil cores were also obtained from Axel Heiberg Island and analyzed in the laboratory. A controlled core thawing experiment was carried out, and observed methane fluxes were compared to modeled methane fluxes. We find that accurate model simulation of methane fluxes needs to satisfy two requirements:(1) microbial biomass needs to be dynamically simulated, and (2) high-affinity methanotrophs need to be represented. With these 2 features, our model is able to reproduce observed temperature and soil moisture sensitivities of high affinity methanotrophs, which are twice as sensitive to temperature than the low affinity methanotrophs and are active under saturated moisture conditions. The model is also able to accurately reproduce the time rate of change of microbial oxidation of atmospheric methane. Finally, we discuss the remaining biases and uncertainties in the model, and the challenges of extending models from the laboratory scale to the landscape scale.

  12. Carbon sequestration potential of grazed pasture depends on prior management history

    Science.gov (United States)

    Grazed pastures are often assumed to be net sinks for removing carbon dioxide from the atmosphere and thus, are promoted as a management practice that can help mitigate climate change. The ability to serve as a C sink is especially pronounced following a history of tillage and row crop production. I...

  13. The production of phytolith-occluded carbon in China's forests: implications to biogeochemical carbon sequestration.

    Science.gov (United States)

    Song, Zhaoliang; Liu, Hongyan; Li, Beilei; Yang, Xiaomin

    2013-09-01

    The persistent terrestrial carbon sink regulates long-term climate change, but its size, location, and mechanisms remain uncertain. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and aboveground net primary productivity (ANPP) data of leaf litter and herb layer in China's forests, we estimated the production of phytolith-occluded carbon (PhytOC) in China's forests. The present annual phytolith carbon sink in China's forests is 1.7 ± 0.4 Tg CO2  yr(-1) , 30% of which is contributed by bamboo because the production flux of PhytOC through tree leaf litter for bamboo is 3-80 times higher than that of other forest types. As a result of national and international bamboo afforestation and reforestation, the potential of phytolith carbon sink for China's forests and world's bamboo can reach 6.8 ± 1.5 and 27.0 ± 6.1 Tg CO2  yr(-1) , respectively. Forest management practices such as bamboo afforestation and reforestation may significantly enhance the long-term terrestrial carbon sink and contribute to mitigation of global climate warming.

  14. Erosion of soil organic carbon: implications for carbon sequestration

    Science.gov (United States)

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

    2009-01-01

    Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

  15. An Experimental Study on the Thermal Resistance Characteristics of Layered Heat Sink

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joung Ha [Department of Mechanical Engineering, Graduate School of Hanyang University, Seoul (Korea); Yun, Jae Ho; Kwon, Oh Kyung [Air-Conditioning and Refrigerating Research Team, Korea Institute of Industrial Technology, Chonan (Korea); Lee, Chang Sik [Department of Mechanical Engineering, Hanyang University, Seoul (Korea)

    2001-04-01

    This paper has been made to investigate the thermal performance characteristics for the several types of layered aluminum heat sinks with offset-trip fin. Heat sinks with different fin height, fin length, number of fin layer and slanted fin are prepared and tested for natural convection as well as forced convection. The experimental results for layered heat sink (LHS) are compared to those for advanced pin fin heat sink (PHS) so that the appropriate heat sink can be designed or chosen according to the heating conditions. The overall heat transfer performances for LHS are almost comparable to those of PHS under natural convection, and become 1.2 {approx} 1.5 times as high as those of PHS under forced convection situation. This study shows that fin height and number of fin layer are important parameters, which have a serious influence on thermal performance for layered heat sinks. 6 refs., 14 figs., 1 tab.

  16. LPTA: Location Predictive and Time Adaptive Data Gathering Scheme with Mobile Sink for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Chuan Zhu

    2014-01-01

    Full Text Available This paper exploits sink mobility to prolong the lifetime of sensor networks while maintaining the data transmission delay relatively low. A location predictive and time adaptive data gathering scheme is proposed. In this paper, we introduce a sink location prediction principle based on loose time synchronization and deduce the time-location formulas of the mobile sink. According to local clocks and the time-location formulas of the mobile sink, nodes in the network are able to calculate the current location of the mobile sink accurately and route data packets timely toward the mobile sink by multihop relay. Considering that data packets generating from different areas may be different greatly, an adaptive dwelling time adjustment method is also proposed to balance energy consumption among nodes in the network. Simulation results show that our data gathering scheme enables data routing with less data transmission time delay and balance energy consumption among nodes.

  17. Geophysical Characterization of the Salna Sinking Zone, Garhwal Himalaya, India

    Science.gov (United States)

    Sastry, Rambhatla G.; Mondal, Suman K.

    2013-01-01

    Infrastructure and communication facilities are repeatedly affected by ground deformation in Gharwal Himalaya, India; for effective remediation measures, a thorough understanding of the real reasons for these movements is needed. In this regard, we undertook an integrated geophysical and geotechnical study of the Salna sinking zone close to the Main Central Thrust in Garhwal Himalaya. Our geophysical data include eight combined electrical resistivity tomography (ERT) and induced polarization imaging (IPI) profiles spanning 144-600 m, with 3-10 m electrode separation in the Wenner-Schlumberger configuration, and five micro-gravity profiles with 10-30 m station spacing covering the study region. The ERT sections clearly outline the heterogeneity in the subsurface lithology. Further, the ERT, IPI, and shaliness (shaleyness) sections infer the absence of clayey horizons and slip surfaces at depth. However, the Bouguer gravity analysis has revealed the existence of several faults in the subsurface, much beyond the reach of the majority of ERT sections. These inferred vertical to subvertical faults run parallel to the existing major lineaments and tectonic elements of the study region. The crisscross network of inferred faults has divided the entire study region into several blocks in the subsurface. Our studies stress that the sinking of the Salna village area is presently taking place along these inferred vertical to subvertical faults. The Chamoli earthquake in March 1999 probably triggered seismically induced ground movements in this region. The absence of few gravity-inferred faults in shallow ERT sections may hint at blind faults, which could serve as future source(s) for geohazards in the study region. Soil samples at two sites of study region were studied in a geotechnical laboratory. These, along with stability studies along four slope sections, have indicated the critical state of the study region. Thus, our integrated studies emphasize the crucial role of

  18. Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization.

    Science.gov (United States)

    Zhang, Weixin; Hendrix, Paul F; Dame, Lauren E; Burke, Roger A; Wu, Jianping; Neher, Deborah A; Li, Jianxiong; Shao, Yuanhu; Fu, Shenglei

    2013-01-01

    A recent review concluded that earthworm presence increases CO₂ emissions by 33% but does not affect soil organic carbon stocks. However, the findings are controversial and raise new questions. Here we hypothesize that neither an increase in CO₂ emission nor in stabilized carbon would entirely reflect the earthworms' contribution to net carbon sequestration. We show how two widespread earthworm invaders affect net carbon sequestration through impacts on the balance of carbon mineralization and carbon stabilization. Earthworms accelerate carbon activation and induce unequal amplification of carbon stabilization compared with carbon mineralization, which generates an earthworm-mediated 'carbon trap'. We introduce the new concept of sequestration quotient to quantify the unequal processes. The patterns of CO₂ emission and net carbon sequestration are predictable by comparing sequestration quotient values between treatments with and without earthworms. This study clarifies an ecological mechanism by which earthworms may regulate the terrestrial carbon sink.

  19. A large CO2 sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    L. C. Cotovicz Jr.

    2015-03-01

    Full Text Available In contrast to its small surface area, the coastal zone plays a disproportionate role in the global carbon cycle. Carbon production, transformation, emission and burial rates at the land–ocean interface are still poorly known, especially in tropical regions. Surface water pCO2 and ancillary parameters were monitored during nine field campaigns between April 2013 and April 2014 in Guanabara Bay, a tropical eutrophic to hypertrophic semi-enclosed estuarine embayment surrounded by the city of Rio de Janeiro, SE-Brazil. Water pCO2 varied between 22 and 3715 ppmv in the Bay showing spatial, diurnal and seasonal trends that mirrored those of dissolved oxygen (DO and Chlorophyll a (Chl a. Marked pCO2 undersaturation was prevalent in the shallow, confined and thermally stratified waters of the upper bay, whereas pCO2 oversaturation was restricted to sites close to the small river mouths and small sewage channels, which covered only 10% of the bay's area. Substantial daily variations in pCO2 (up to 395 ppmv between dawn and dusk were also registered and could be integrated temporally and spatially for the establishment of net diurnal, seasonal and annual CO2 fluxes. In contrast to other estuaries worldwide, Guanabara Bay behaved as a net sink of atmospheric CO2, a property enhanced by the concomitant effects of strong radiation intensity, thermal stratification, and high availability of nutrients, which promotes phytoplankton development and net autotrophy. In the inner part of the bay, the calculated annual CO2 sink (−19.6 mol C m2 yr-1 matched the organic carbon burial in the sediments reported in the literature. The carbon sink and autotrophy of Guanabara Bay was driven by planktonic primary production promoted by eutrophication, and by its typology of marine embayment lacking the classical extended estuarine mixing zone, in contrast to river-dominated estuarine systems, which are generally net heterotrophic and CO2 emitters. Our results show that

  20. Contribution of semi-arid ecosystems to interannual variability of the global carbon cycle.

    Science.gov (United States)

    Poulter, Benjamin; Frank, David; Ciais, Philippe; Myneni, Ranga B; Andela, Niels; Bi, Jian; Broquet, Gregoire; Canadell, Josep G; Chevallier, Frederic; Liu, Yi Y; Running, Steven W; Sitch, Stephen; van der Werf, Guido R

    2014-05-29

    The land and ocean act as a sink for fossil-fuel emissions, thereby slowing the rise of atmospheric carbon dioxide concentrations. Although the uptake of carbon by oceanic and terrestrial processes has kept pace with accelerating carbon dioxide emissions until now, atmospheric carbon dioxide concentrations exhibit a large variability on interannual timescales, considered to be driven primarily by terrestrial ecosystem processes dominated by tropical rainforests. We use a terrestrial biogeochemical model, atmospheric carbon dioxide inversion and global carbon budget accounting methods to investigate the evolution of the terrestrial carbon sink over the past 30 years, with a focus on the underlying mechanisms responsible for the exceptionally large land carbon sink reported in 2011 (ref. 2). Here we show that our three terrestrial carbon sink estimates are in good agreement and support the finding of a 2011 record land carbon sink. Surprisingly, we find that the global carbon sink anomaly was driven by growth of semi-arid vegetation in the Southern Hemisphere, with almost 60 per cent of carbon uptake attributed to Australian ecosystems, where prevalent La Niña conditions caused up to six consecutive seasons of increased precipitation. In addition, since 1981, a six per cent expansion of vegetation cover over Australia was associated with a fourfold increase in the sensitivity of continental net carbon uptake to precipitation. Our findings suggest that the higher turnover rates of carbon pools in semi-arid biomes are an increasingly important driver of global carbon cycle inter-annual variability and that tropical rainforests may become less relevant drivers in the future. More research is needed to identify to what extent the carbon stocks accumulated during wet years are vulnerable to rapid decomposition or loss through fire in subsequent years.

  1. Sinking of armour layer around a cylinder exposed to a current

    DEFF Research Database (Denmark)

    Nielsen, Anders Wedel; Sumer, B. Mutlu; Fredsøe, Jørgen

    2011-01-01

    in the scour protection may cause sinking of the scour protection. This may reduce the stability of the monopile and change for instance the natural frequency of the dynamic response of an offshore wind turbine in an unfavourable manner. The most important flow process with regard to transport of sediment...... and sinking of the scour protection is found to be the horseshoe vortex. It is found that a larger pile diameter relative to the size of the protection stones will cause a larger sinking and that two layers of stones will decrease the sinking relative to one layer of stones with the same size....

  2. New Configurations of Micro Plate-Fin Heat Sink to Reduce Coolant Pumping Power

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Rosendahl, Lasse

    2012-01-01

    The thermal resistance of heat exchangers has a strong influence on the electric power produced by a thermoelectric generator (TEG). In this work, a real TEG device is applied to three configurations of micro plate-fin heat sink. The distance between certain microchannels is varied to find...... the optimum heat sink configuration. The particular focus of this study is to reduce the coolant mass flow rate by considering the thermal resistances of the heat sinks and, thereby, to reduce the coolant pumping power in the system. The threedimensional governing equations for the fluid flow and the heat...... heat sink configurations reduces the coolant pumping power in the system....

  3. Modeling and simulation of heat sinks for computer processors in COMSOL Multiphysics

    OpenAIRE

    2012-01-01

    In this study, the heat transfer of three desktop- computer heat sinks was analyzed. The objective of using these heat sinks is to avoid overheating of the computer’s processing unit and in turn reduce the corresponding loss in the unit’s service time. The heat sinks were modeled using COMSOL Multiphysics with the actual dimensions of the devices, and heat generation was modeled with a point source. In the next step, the heat sink designs were modified to achieve a lower temperature in the hi...

  4. A method for intermediate flooding and sinking simulation of a damaged floater in time domain

    OpenAIRE

    Ju-Sung Kim; Myung-Il Roh; Seung-Ho Ham

    2017-01-01

    When a floater such as a ship or an offshore structure is damaged in the sea, it is necessary to determine whether the floater will sink in water or not. If the floater will sink, the time to sink should be estimated to make an emergency plan. In addition, causes of the flooding should be investigated carefully. For this purpose, a method for performing intermediate flooding and sinking simulation of the damaged floater in time domain is proposed in this study. Overall process of the proposed...

  5. A Comprehensive Study of Data Collection Schemes Using Mobile Sinks in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Abdul Waheed Khan

    2014-02-01

    Full Text Available Recently sink mobility has been exploited in numerous schemes to prolong the lifetime of wireless sensor networks (WSNs. Contrary to traditional WSNs where sensory data from sensor field is ultimately sent to a static sink, mobile sink-based approaches alleviate energy-holes issues thereby facilitating balanced energy consumption among nodes. In mobility scenarios, nodes need to keep track of the latest location of mobile sinks for data delivery. However, frequent propagation of sink topological updates undermines the energy conservation goal and therefore should be controlled. Furthermore, controlled propagation of sinks’ topological updates affects the performance of routing strategies thereby increasing data delivery latency and reducing packet delivery ratios. This paper presents a taxonomy of various data collection/dissemination schemes that exploit sink mobility. Based on how sink mobility is exploited in the sensor field, we classify existing schemes into three classes, namely path constrained, path unconstrained, and controlled sink mobility-based schemes. We also organize existing schemes based on their primary goals and provide a comparative study to aid readers in selecting the appropriate scheme in accordance with their particular intended applications and network dynamics. Finally, we conclude our discussion with the identification of some unresolved issues in pursuit of data delivery to a mobile sink.

  6. Temperature Histories in Ceramic-Insulated Heat-Sink Nozzle

    Science.gov (United States)

    Ciepluch, Carl C.

    1960-01-01

    Temperature histories were calculated for a composite nozzle wall by a simplified numerical integration calculation procedure. These calculations indicated that there is a unique ratio of insulation and metal heat-sink thickness that will minimize total wall thickness for a given operating condition and required running time. The optimum insulation and metal thickness will vary throughout the nozzle as a result of the variation in heat-transfer rate. The use of low chamber pressure results in a significant increase in the maximum running time of a given weight nozzle. Experimentally measured wall temperatures were lower than those calculated. This was due in part to the assumption of one-dimensional or slab heat flow in the calculation procedure.

  7. Influence of Transverse Magnetic Field on Microchannel Heat Sink Performance

    Directory of Open Access Journals (Sweden)

    K. Narrein

    2016-01-01

    Full Text Available The aim of the present numerical investigation is to analyze the effects of transverse magnetic field on heat transfer and fluid flow characteristics in a rectangular microchannel heat sink (MCHS. The effects of Hartmann number, channel aspect ratio, total channel height and total channel width on heat transfer and fluid flow characteristics are widely investigated. The governing equations for three-dimensional steady, laminar flow and conjugate heat transfer of a microchannel are solved using the finite volume method. The obtained results are discussed with various combinations of pertinent parameters involved in the study. The results reveal that magnetic field can enhance the thermal performance of the MCHS but it is accompanied with a slight increase in pressure drop.

  8. Investigation of heat sink of endothermic hydrocarbon fuels

    Institute of Scientific and Technical Information of China (English)

    GUO Yong-sheng; LIN Rui-sen

    2005-01-01

    Endothermic hydrocarbon fuels are advanced coolants for high-temperature structures of spacecraft. No data of tested-cooling-ability of endothermic fuels have been broadly discussed in literature. In this work a high-temperature flow calorimeter was designed, and the cooling capacity of six different hydrocarbon fuels were measured. Experimental results showed that these hydrocarbon fuels have capacity for cooling high-temperature structures, and that the cooling capacity of fuel N-1 can reach 3.15 M J/kg, which can nearly satisfy the requirement of thermal management for a Mach 3 cruise aircraft, whose heat sink requirement is about 3.5 M J/kg. The endothermic velocity of hydrocarbon fuels was also measured by the calorimeter.

  9. CURRENT TECHNOLOGY AND INNOVATIONS IN FREEZE SHAFT SINKING IN CHINA

    Institute of Scientific and Technical Information of China (English)

    张铭; 翁家杰; 夏正明

    1991-01-01

    This paper gives a brief review of the development of shaft sinking by artificial ground freezing since 1949 when new China was founded. Several shaft freezing schemes which have been successfully applied from the economic and safe viewpoints are presented. Current technology and some innovative techniques,especially the shah lining which have experienced major improvements over the last four decades,are briefly reviewed. The technique of the in-situ pour concrete incorporating ailica fume with higher early strength under low temperature curing conditions is described. The temperature field in shah freezing and its finite difference solution are given in this paper. A recently developed method combining freeze wall model test with back analysis technique based on numerical simulation is also described.

  10. Liquid metal heat sink for high-power laser diodes

    Science.gov (United States)

    Vetrovec, John; Litt, Amardeep S.; Copeland, Drew A.; Junghans, Jeremy; Durkee, Roger

    2013-02-01

    We report on the development of a novel, ultra-low thermal resistance active heat sink (AHS) for thermal management of high-power laser diodes (HPLD) and other electronic and photonic components. AHS uses a liquid metal coolant flowing at high speed in a miniature closed and sealed loop. The liquid metal coolant receives waste heat from an HPLD at high flux and transfers it at much reduced flux to environment, primary coolant fluid, heat pipe, or structure. Liquid metal flow is maintained electromagnetically without any moving parts. Velocity of liquid metal flow can be controlled electronically, thus allowing for temperature control of HPLD wavelength. This feature also enables operation at a stable wavelength over a broad range of ambient conditions. Results from testing an HPLD cooled by AHS are presented.

  11. Dust deposition: iron source or sink? A case study

    Directory of Open Access Journals (Sweden)

    Y. Ye

    2011-08-01

    Full Text Available A significant decrease of dissolved iron (DFe concentration has been observed after dust addition into mesocosms during the DUst experiment in a low Nutrient low chlorophyll Ecosystem (DUNE, carried out in the summer of 2008. Due to low biological productivity at the experiment site, biological consumption of iron can not explain the magnitude of DFe decrease. To understand processes regulating the observed DFe variation, we simulated the experiment using a one-dimensional model of the Fe biogeochemical cycle, coupled with a simple ecosystem model. Different size classes of particles and particle aggregation are taken into account to describe the particle dynamics. DFe concentration is regulated in the model by dissolution from dust particles and adsorption onto particle surfaces, biological uptake, and photochemical mobilisation of particulate iron.

    The model reproduces the observed DFe decrease after dust addition well. This is essentially explained by particle adsorption and particle aggregation that produces a high export within the first 24 h. The estimated particle adsorption rates range between the measured adsorption rates of soluble iron and those of colloidal iron, indicating both processes controlling the DFe removal during the experiment. A dissolution timescale of 3 days is used in the model, instead of an instantaneous dissolution, underlining the importance of dissolution kinetics on the short-term impact of dust deposition on seawater DFe.

    Sensitivity studies reveal that initial DFe concentration before dust addition was crucial for the net impact of dust addition on DFe during the DUNE experiment. Based on the balance between abiotic sinks and sources of DFe, a critical DFe concentration has been defined, above which dust deposition acts as a net sink of DFe, rather than a source. Taking into account the role of excess iron binding ligands and biotic processes, the critical DFe concentration might be applied to

  12. [Seagrass ecosystems: contributions to and mechanisms of carbon sequestration].

    Science.gov (United States)

    Qiu, Guang-Long; Lin, Hsing-Juh; Li, Zong-Shan; Fan, Hang-Qing; Zhou, Hao-Lang; Liu, Guo-Hua

    2014-06-01

    The ocean's vegetated habitats, in particular seagrasses, mangroves and salt marshes, each capture and store a comparable amount of carbon per year, forming the Earth's blue carbon sinks, the most intense carbon sinks on the planet. Seagrass meadows, characterized by high primary productivity, efficient water column filtration and sediment stability, have a pronounced capacity for carbon sequestration. This is enhanced by low decomposition rates in anaerobic seagrass sediments. The carbon captured by seagrass meadows contributes significantly to the total blue carbon. At a global scale, seagrass ecosystems are carbon sink hot spots and have profound influences on the global carbon cycle. This importance combined with the many other functions of seagrass meadows places them among the most valuable ecosystems in the world. Unfortunately, seagrasses are declining globally at an alarming rate owing to anthropogenic disturbances and climate change, making them also among the most threatened ecosystems on the Earth. The role of coastal systems in carbon sequestration has received far too little attention and thus there are still many uncertainties in evaluating carbon sequestration of global seagrass meadows accurately. To better assess the carbon sequestration of global seagrass ecosystems, a number of scientific issues should be considered with high priorities: 1) more accurate measurements of seagrass coverage at national and global levels; 2) more comprehensive research into species- and location-specific carbon sequestration efficiencies; 3) in-depth exploration of the effects of human disturbance and global climate change on carbon capture and storage by seagrass ecosystems.

  13. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    Science.gov (United States)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  14. Depression of sink activity precedes the inhibition of biomass production in tomato plants subjected to potassium deficiency stress.

    Science.gov (United States)

    Kanai, S; Ohkura, K; Adu-Gyamfi, J J; Mohapatra, P K; Nguyen, N T; Saneoka, H; Fujita, K

    2007-01-01

    Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown hydroponically inside the greenhouse of Hiroshima University, Japan. The adverse effects of potassium (K) deficiency stress on the source-sink relationship during the early reproductive period was examined by withdrawing K from the rooting medium for a period of 21 d. Fruits and stem were the major sink organs for the carbon assimilates from the source. A simple non-destructive micro-morphometric technique was used to measure growth of these organs. The effect of K deficiency was studied on the apparent photosynthesis (source activity), leaf area, partitioning (13)C, sugar concentration, K content, and fruit and stem diameters of the plant. Compared with the control, K deficiency treatment severely decreased biomass of all organs. The treatment also depressed leaf photosynthesis and transport of (13)C assimilates, but the impact of stress on these activities became evident only after fruit and stem diameter expansions were down-regulated. These results suggested that K deficiency diminished sink activity in tomato plants prior to its effect on the source activity because of a direct effect on the water status of the former. The lack of demand in growth led to the accumulation of sugars in leaves and concomitant fall in photosynthetic activity. Since accumulation of K and sugars in the fruit was not affected, low K levels of the growing medium might not have affected the fruit quality. The micro-morphometric technique can be used as a reliable tool for monitoring K deficiency during fruiting of tomato. K deficiency directly hindered assimilate partitioning, and the symptoms were considered more detrimental compared with P deficiency.

  15. Evidence for dissolved organic matter as the primary source and sink of photochemically produced hydroxyl radical in arctic surface waters.

    Science.gov (United States)

    Page, Sarah E; Logan, J Robert; Cory, Rose M; McNeill, Kristopher

    2014-04-01

    Hydroxyl radical (˙OH) is an indiscriminate oxidant that reacts at near-diffusion-controlled rates with organic carbon. Thus, while ˙OH is expected to be an important oxidant of dissolved organic matter (DOM) and other recalcitrant compounds, the role of ˙OH in the oxidation of these compounds in aquatic ecosystems is not well known due to the poorly constrained sources and sinks of ˙OH, especially in pristine (unpolluted) natural waters. We measured the rates of ˙OH formation and quenching across a range of surface waters in the Arctic varying in concentrations of expected sources and sinks of ˙OH. Photochemical formation of ˙OH was observed in all waters tested, with rates of formation ranging from 2.6 ± 0.6 to 900 ± 100 × 10(-12) M s(-1). Steady-state concentrations ranged from 2 ± 1 to 290 ± 60 × 10(-17) M, and overlapped with previously reported values in surface waters. While iron-mediated photo-Fenton reactions likely contributed to the observed ˙OH production, several lines of evidence suggest that DOM was the primary source and sink of photochemically produced ˙OH in pristine arctic surface waters. DOM from first-order or headwater streams was more efficient in producing ˙OH than what has previously been reported for DOM, and ˙OH formation decreased with increasing residence time of DOM in sunlit surface waters. Despite the ubiquitous formation of ˙OH in arctic surface waters observed in this study, photochemical ˙OH formation was estimated to contribute ≤4% to the observed photo-oxidation of DOM; however, key uncertainties in this estimate must be addressed before ruling out the role of ˙OH in the oxidation of DOM in these waters.

  16. Future forest aboveground carbon dynamics in the central United States: the importance of forest demographic processes

    Science.gov (United States)

    Jin, Wenchi; He, Hong S.; Thompson, Frank R.; Wang, Wen J.; Fraser, Jacob S.; Shifley, Stephen R.; Hanberry, Brice B.; Dijak, William D.

    2017-01-01

    The Central Hardwood Forest (CHF) in the United States is currently a major carbon sink, there are uncertainties in how long the current carbon sink will persist and if the CHF will eventually become a carbon source. We used a multi-model ensemble to investigate aboveground carbon density of the CHF from 2010 to 2300 under current climate. Simulations were done using one representative model for each of the simple, intermediate, and complex demographic approaches (ED2, LANDIS PRO, and LINKAGES, respectively). All approaches agreed that the current carbon sink would persist at least to 2100. However, carbon dynamics after current carbon sink diminishes to zero differ for different demographic modelling approaches. Both the simple and the complex demographic approaches predicted prolonged periods of relatively stable carbon densities after 2100, with minor declines, until the end of simulations in 2300. In contrast, the intermediate demographic approach predicted the CHF would become a carbon source between 2110 and 2260, followed by another carbon sink period. The disagreement between these patterns can be partly explained by differences in the capacity of models to simulate gross growth (both birth and subsequent growth) and mortality of short-lived, relatively shade-intolerant tree species. PMID:28165483

  17. Braze Development of Graphite Fiber for Use in Phase Change Material Heat Sinks

    Science.gov (United States)

    Quinn, Gregory; Beringer, Woody; Gleason, Brian; Stephan, Ryan

    2011-01-01

    Hamilton Sundstrand (HS), together with NASA Johnson Space Center, developed methods to metallurgically join graphite fiber to aluminum. The goal of the effort was to demonstrate improved thermal conductance, tensile strength and manufacturability compared to existing epoxy bonded techniques. These improvements have the potential to increase the performance and robustness of phase change material heat sinks that use graphite fibers as an interstitial material. Initial work focused on evaluating joining techniques from four suppliers, each consisting of a metallization step followed by brazing or soldering of one inch square blocks of Fibercore graphite fiber material to aluminum end sheets. Results matched the strength and thermal conductance of the epoxy bonded control samples, so two suppliers were down-selected for a second round of braze development. The second round of braze samples had up to a 300% increase in strength and up to a 132% increase in thermal conductance over the bonded samples. However, scalability and repeatability proved to be significant hurdles with the metallization approach. An alternative approach was pursued which used a nickel braze allow to prepare the carbon fibers for joining with aluminum. Initial results on sample blocks indicate that this approach should be repeatable and scalable with good strength and thermal conductance when compared with epoxy bonding.

  18. Southern Ocean CO2 sink: the contribution of the sea ice

    DEFF Research Database (Denmark)

    Delille, B.; Vancoppenolle, Martin; Geilfus, Nicolas-Xavier

    2014-01-01

    undersaturation while the underlying oceanic waters remains slightly oversaturated. The decrease from winter to summer of pCO2 in the brines is driven by dilution with melting ice, dissolution of carbonate crystals, and net primary production. As the ice warms, its permeability increases, allowing CO2 transfer......We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines encased in the ice change from a CO2 large oversaturation, relative to the atmosphere, to a marked...... at the air-sea ice interface. The sea ice changes from a transient source to a sink for atmospheric CO2. We upscale these observations to the whole Antarctic sea ice cover using the NEMO-LIM3 large-scale sea ice-ocean and provide first esti- mates of spring and summer CO2 uptake from the atmosphere...

  19. Lift Enhancement of a Vortex-Sink Attached to a Flat Plate

    CERN Document Server

    Xia, Xi; Mohseni, Kamran

    2012-01-01

    As observed in natural fliers, stabilized vortices on the surface of an airfoil or wing could provide lift enhancement. Similar concept can be applied in fixed lifting surfaces. Potential flow theory is employed to model lift enhancement by attaching a vortex-sink pair to the top surface of a flat plate in a pseudo-steady flow. Using this flow model, a parametric study on the location of the vortex-sink pair is performed in order to optimize lift enhancement. Lift coefficient calculations are presented for a range of vortex-sink positions, vortex-sink strengths, and flat-plate angles of attack. It is shown that beyond the lift contribution terms due to the vortex-sink strength, lift enhancement could be also achieved by a translating velocity of the vortex-sink in a non-equilibrium position. This vortex-sink velocity term is more pronounced when the vortex-sink is placed close to the top surface of the flat-plate near the leading or the trailing edges of the flat plate. It is concluded that increasing the vor...

  20. On Mobility Management in Multi-Sink Sensor Networks for Geocasting of Queries

    Directory of Open Access Journals (Sweden)

    Paul Havinga

    2011-12-01

    Full Text Available In order to efficiently deal with location dependent messages in multi-sink wireless sensor networks (WSNs, it is key that the network informs sinks what geographical area is covered by which sink. The sinks are then able to efficiently route messages which are only valid in particular regions of the deployment. In our previous work (see the 5th and 6th cited documents, we proposed a combined coverage area reporting and geographical routing protocol for location dependent messages, for example, queries that are injected by sinks. In this paper, we study the case where we have static sinks and mobile sensor nodes in the network. To provide up-to-date coverage areas to sinks, we focus on handling node mobility in the network. We discuss what is a better method for updating the routing structure (i.e., routing trees and coverage areas to handle mobility efficiently: periodic global updates initiated from sinks or local updates triggered by mobile sensors. Simulation results show that local updating perform very well in terms of query delivery ratio. Local updating has a better scalability to increasing network size. It is also more energy efficient than ourpreviously proposed approach, where global updating in networks have medium mobility rate and speed.

  1. Sinking of irregular shape blocks into marine seabed under wave-induced liquefaction

    DEFF Research Database (Denmark)

    Kirca, Özgür

    2013-01-01

    The sinking of initially buried irregular blocks into the seabed under wave-induced liquefaction was investigated by experimental methods. Pore-water pressure in the soil, water surface elevation time series and block displacements were measured. Results indicated that initiation of sinking...

  2. STABLE CARBON ISOTOPES OF HCO//3 IN THE AQUIA AQUIFER, MARYLAND: EVIDENCE FOR AN ISOTOPICALLY HEAVY SOURCE OF CO//2.

    Science.gov (United States)

    Chapelle, Francis H.; Knobel, LeRoy L.

    1985-01-01

    Identifying sources and sinks of dissolved inorganic carbon species is an important step in understanding the geochemistry of ground-water systems. This is particularly important for Atlantic Coastal Plain aquifers because bicarbonate (HCO//3** minus ) is frequently the major dissolved anion. The purpose of this paper is to document the stable carbon isotope composition of dissolved inorganic carbon in the Aquia aquifer, Maryland, and to use this data to help identify sources and sinks of dissolved HCO//3** minus . Subjects covered include hydrogeology, ground-water chemistry, sources and sinks, and others. Refs.

  3. Carbon sequestration potential for forage and pasture systems

    Science.gov (United States)

    Grassland soils represent a large reservoir of organic and inorganic carbon. Regionally, grasslands are annual CO2 sources or sinks depending on crop and soil management, current soil organic carbon (SOC) concentration and climate. Land management changes (LMC) impact SOC sequestration rate, the du...

  4. Source to sink: Evolution of lignin composition in the Madre de Dios River system with connection to the Amazon basin and offshore

    Science.gov (United States)

    Feng, Xiaojuan; Feakins, Sarah J.; Liu, Zongguang; Ponton, Camilo; Wang, Renée. Z.; Karkabi, Elias; Galy, Valier; Berelson, William M.; Nottingham, Andrew T.; Meir, Patrick; West, A. Joshua

    2016-05-01

    While lignin geochemistry has been extensively investigated in the Amazon River, little is known about lignin distribution and dynamics within deep, stratified river channels or its transformations within soils prior to delivery to rivers. We characterized lignin phenols in soils, river particulate organic matter (POM), and dissolved organic matter (DOM) across a 4 km elevation gradient in the Madre de Dios River system, Peru, as well as in marine sediments to investigate the source-to-sink evolution of lignin. In soils, we found more oxidized lignin in organic horizons relative to mineral horizons. The oxidized lignin signature was maintained during transfer into rivers, and lignin was a relatively constant fraction of bulk organic carbon in soils and riverine POM. Lignin in DOM became increasingly oxidized downstream, indicating active transformation of dissolved lignin during transport, especially in the dry season. In contrast, POM accumulated undegraded lignin downstream during the wet season, suggesting that terrestrial input exceeded in-river degradation. We discovered high concentrations of relatively undegraded lignin in POM at depth in the lower Madre de Dios River in both seasons, revealing a woody undercurrent for its transfer within these deep rivers. Our study of lignin evolution in the soil-river-ocean continuum highlights important seasonal and depth variations of river carbon components and their connection to soil carbon pools, providing new insights into fluvial carbon dynamics associated with the transfer of lignin biomarkers from source to sink.

  5. A Thesis on Design Optimization of Heat Sink in Power Electronics

    Directory of Open Access Journals (Sweden)

    P.Chennakesavarao

    2014-10-01

    Full Text Available The heat sinks are used in electronic systems to remove heat from the chip and effectively transfer it to the ambient. The heat sink geometry is designed by the mechanical engineers with the primary aim of reducing the thermal resistance of the heat sink for better cooling in the electronic systems. Due to the proximity of the heat sink with the ICs, the RF fields created by RF currents in the ICs/PCBs gets coupled to heat sinks. Hence, the coupled RF current can cause radiated emission. This radiated noise from the device can couple and disturb the functioning of the nearby electronic systems. Also this radiated emission from the device poses a problem to the system compliance with respect to EMI/EMC regulations. The international EMI/EMC standards require the radiated emission from the electronic devices to be kept below the specified limits. As a result the design of Heat Sink is very important factor for the efficient operation of the electronic equipment. In this project design optimization of a Heat sink in a Power amplifier is performed to reduce the weight and size .Power amplifier is electronic equipment mounted in an army vehicle. The power modules inside the amplifier generates a heat of 1440 Watts and a temperature of 140 0c.Two Heat sinks are used to dissipate the heat generated inside the equipment and maintain a temperature of less than 850c. The existing heat sink which is being used is weighing around 10.3kgs and height of 51mm; as a result the unit is very robust. The objective of my project is To design & optimize the heat sink to reduce the weight and size. The optimized heat sink should also dissipate heat generated by power modules and maintain a temperature of less than 850c inside. To achieve the design a steady state thermal analysis will be performed on the heat sink and plot the Temperature distribution on the fins. Based on the above analysis results we will increase/decrease the number of fins, thickness of fins, and

  6. Thermal performance of carbon nanotube nanofluids in solar microchannel collectors: an experimental study

    OpenAIRE

    Ahlatli, Selim; Maré, Thierry; Estellé, Patrice; Doner, Nimeti

    2016-01-01

    International audience; Many studies show that nanofluids, especially with carbon nanotubes, improve heat transfer. Other studies show that a nanofluid is a good candidate for solar systems because of its good absorptivity. We are facing an increasing number of miniaturized and more powerful systems. Especially in microelectronics, small heat sinks with high heat transfer are being developed, called micro-channel heat sinks (MCHS). In this paper, the heat transfer behavior of carbon nanotube–...

  7. Using NDACC column measurements of carbonyl sulfide to estimate its sources and sinks

    Science.gov (United States)

    Wang, Yuting; Marshall, Julia; Palm, Mathias; Deutscher, Nicholas; Roedenbeck, Christian; Warneke, Thorsten; Notholt, Justus; Baker, Ian; Berry, Joe; Suntharalingam, Parvadha; Jones, Nicholas; Mahieu, Emmanuel; Lejeune, Bernard; Hannigan, James; Conway, Stephanie; Strong, Kimberly; Campbell, Elliott; Wolf, Adam; Kremser, Stefanie

    2016-04-01

    Carbonyl sulfide (OCS) is taken up by plants during photosynthesis through a similar pathway as carbon dioxide (CO2), but is not emitted by respiration, and thus holds great promise as an additional constraint on the carbon cycle. It might act as a sort of tracer of photosynthesis, a way to separate gross primary productivity (GPP) from the net ecosystem exchange (NEE) that is typically derived from flux modeling. However the estimates of OCS sources and sinks still have significant uncertainties, which make it difficult to use OCS as a photosynthetic tracer, and the existing long-term surface-based measurements are sparse. The NDACC-IRWG measures the absorption of OCS in the atmosphere, and provides a potential long-term database of OCS total/partial columns, which can be used to evaluate OCS fluxes. We have retrieved OCS columns from several NDACC sites around the globe, and compared them to model simulation with OCS land fluxes based on the simple biosphere model (SiB). The disagreement between the measurements and the forward simulations indicates that (1) the OCS land fluxes from SiB are too low in the northern boreal region; (2) the ocean fluxes need to be optimized. A statistical linear flux model describing OCS is developed in the TM3 inversion system, and is used to estimate the OCS fluxes. We performed flux inversions using only NOAA OCS surface measurements as an observational constraint and with both surface and NDACC OCS column measurements, and assessed the differences. The posterior uncertainties of the inverted OCS fluxes decreased with the inclusion of NDACC data comparing to those using surface data only, and could be further reduced if more NDACC sites were included.

  8. Evaluating Thermoelectric Power Generation Device Performance Using a Rectangular Microchannel Heat Sink

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Rosendahl, Lasse

    2011-01-01

    In this work, a microchannel heat sink is applied to a thermoelectric power generation (TEG) device and compared with a traditional heat sink. The advantages and disadvantages of using each heat sink in a TEG device are evaluated. The microchannel hydraulic diameter is 5.33 x 10-4 m...... and that of the macrochannel is 2.13 x 10-3 m. Pressure drops and heat removed in the micro heat sink configuration are obtained for six different mass flow rates for the laminar and turbulent fluid flow regimes. By computationally applying a constant temperature difference between the hot and cold sides of the TEG, the fluid...... and thermal parameters are considered for both laminar and turbulent regimes in the channels. Furthermore, using the temperature difference through each TEG, the system efficiency is calculated. The results show that the microchannel heat sink gives a higher pressure drop, but the heat flow across the TEG...

  9. Multiple Sink Positioning and Routing to Maximize the Lifetime of Sensor Networks

    Science.gov (United States)

    Kim, Haeyong; Kwon, Taekyoung; Mah, Pyeongsoo

    In wireless sensor networks, the sensor nodes collect data, which are routed to a sink node. Most of the existing proposals address the routing problem to maximize network lifetime in the case of a single sink node. In this paper, we extend this problem into the case of multiple sink nodes. To maximize network lifetime, we consider the two problems: (i) how to position multiple sink nodes in the area, and (ii) how to route traffic flows from sensor nodes to sink nodes. In this paper, the solutions to these problems are formulated into a Mixed Integer Linear Programming (MILP) model. However, it is computationally difficult to solve the MILP formulation as the size of sensor network grows because MILP is NP-hard. Thus, we propose a heuristic algorithm, which produces a solution in polynomial time. From our experiments, we found out that the proposed heuristic algorithm provides a near-optimal solution for maximizing network lifetime in dense sensor networks.

  10. A Distributed Method for Modeling Effective Cryogenic Flat Cable Heat Sinking

    Science.gov (United States)

    Zobrist, N. R.; Daal, M.; Sadoulet, B.; Golwala, S.

    2014-09-01

    A common challenge in low temperature instrumentation is adequately heat sinking signal wires between room temperature and devices at base temperature. Using cryostat space for adequate heat sinking typically comes at the cost of complexity or experimental space. As such, it is useful to know how much heat sinking is adequate given the materials, heat sources and cooling capacities involved. We present a differential equation for modeling the heat flowing out of a flat cable along an interval over which it is adhered to an insulating interface which is bound to a metallic heat sinking surface and numerical results for realistic heat sinks in the Kelvin range. We also present a computational method for solving this differential equation.

  11. Analytical Thermal and Cost Optimization of Micro-Structured Plate-Fin Heat Sink

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse

    Microchannel heat sinks have been widely used in the field of thermo-fluids due to the rapid growth in technological applications which require high rates of heat transfer in relatively small spaces and volumes. In this work, a micro plate-fin heat sink is optimized parametrically, to minimize...... the thermal resistance and to maximize the cost performance of the heat sink. The width and the height of the microchannels, and the fin thickness are analytically optimized at a wide range of pumping power. Using an effective numeric test, the generated equations also discuss the optimum parameters at three...... sizes of the substrate plat of the heat sink. Results show that, at any pumping power there are specific values of the channel width and fin thickness which produce minimum thermal resistance in the heat sink. The results also illustrate that, a larger channel width and a smaller fin thickness lead...

  12. Modeling of radiation-induced sink evolution in 6061 aluminum alloy in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Il; Kim, Ji Hyun [Department of Nuclear Science and Engineering, School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of); Lee, Gyeong-Geun; Kwon, Junhyun [Division of Nuclear Materials Research, Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of)

    2016-11-15

    The objective of this study is a detailed analysis of the radiation effects on sink generation and growth in order to understand the phenomenon of irradiation hardening of 6061 aluminum alloy in research reactor conditions. In order to have a fundamental understanding, various sink behavior characteristics such as size and number density of dislocation loop, void, and precipitation were calculated and examined. Thereafter, theoretical assessment of various sink effects on irradiation hardening was conducted based on the mean field rate theory (MFRT). Dislocation loop, void, and precipitation were examined by defect flux. For the quantitative analysis of radiation-induced degradation, change in sink size was calculated using number density. 6061 Alloy showed great dependence on precipitation generation and growth. However, dislocation loop and void did not have any significant effect on irradiation hardening. Finally, the behavior of sinks was compared with the experimental results for validation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. The uncertainty of modeled soil carbon stock change for Finland

    Science.gov (United States)

    Lehtonen, Aleksi; Heikkinen, Juha

    2013-04-01

    Countries should report soil carbon stock changes of forests for Kyoto Protocol. Under Kyoto Protocol one can omit reporting of a carbon pool by verifying that the pool is not a source of carbon, which is especially tempting for the soil pool. However, verifying that soils of a nation are not a source of carbon in given year seems to be nearly impossible. The Yasso07 model was parametrized against various decomposition data using MCMC method. Soil carbon change in Finland between 1972 and 2011 were simulated with Yasso07 model using litter input data derived from the National Forest Inventory (NFI) and fellings time series. The uncertainties of biomass models, litter turnoverrates, NFI sampling and Yasso07 model were propagated with Monte Carlo simulations. Due to biomass estimation methods, uncertainties of various litter input sources (e.g. living trees, natural mortality and fellings) correlate strongly between each other. We show how original covariance matrices can be analytically combined and the amount of simulated components reduce greatly. While doing simulations we found that proper handling correlations may be even more essential than accurate estimates of standard errors. As a preliminary results, from the analysis we found that both Southern- and Northern Finland were soil carbon sinks, coefficient of variations (CV) varying 10%-25% when model was driven with long term constant weather data. When we applied annual weather data, soils were both sinks and sources of carbon and CVs varied from 10%-90%. This implies that the success of soil carbon sink verification depends on the weather data applied with models. Due to this fact IPCC should provide clear guidance for the weather data applied with soil carbon models and also for soil carbon sink verification. In the UNFCCC reporting carbon sinks of forest biomass have been typically averaged for five years - similar period for soil model weather data would be logical.

  14. Cold Climate Related Structural Sinks Accommodate Unusual Soil Constituents, Pinelands National Reserve, New Jersey, USA

    Science.gov (United States)

    Demitroff, M.; Lecompte, M. A.; Rock, B. N.

    2009-12-01

    Firestone and others proposed an extraterrestrial (ET) impact upon the Laurentide Ice Sheet 12,900 years ago led to abrupt climate change and left behind a distinct suite of microscopic soil markers. If so, then soil memory of such an extreme event should be apparent across a wide swath of ice-marginal North America. New Jersey’s Pine Barrens has a remarkably well-preserved record of Late Pleistocene soil structures that provide snapshots of rigorous climatic episodes, the youngest of which are potential reservoirs for ET markers. Cryogenic macrostructures are fissures related to episodic temperature and moisture extremes providing excellent chronostratigraphic control - unlike soil horizons that are often affected by denudation and pedogenic modification. Three distinct ground structures were sampled for evidence of infill-related ET markers: 1) two ground (soil) wedges (early Holocene?); 2) a younger sand-wedge cast (late-Wisconsinan?); and 3) an older sand-wedge cast (early-Wisconsinan?). Attendant host sediment and capping colluvium coversand samples were also collected for evidence of ET markers to detect potential source sinks. Our pedocomplex contained elements ranging from Miocene Cohansey Formation basement sands to early-Holocene fluvioeolian coversands. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray analysis (EDX) are being used to characterize soil constituents of interest. Carbon and luminescence dating are underway to provide geomorphic events timing associated with specific soil constituent trap formation. Fly ash collected from a coal-fired electrical plant 13-km distant was also examined. Several soil constituents atypical to the local petrology as currently understood were found. Infill from two ground (soil) wedges contained ~100,000 to ~500,000 magnetic spherules/kg, 25 to 50 translucent amber-colored spherules/kg, 250 to 500 carbon spherules/kg, charcoal, and pieces of glass-like carbon

  15. A fertile peatland forest does not constitute a major greenhouse gas sink

    Directory of Open Access Journals (Sweden)

    A. Meyer

    2013-03-01

    Full Text Available Afforestation has been proposed as a strategy to mitigate the often high greenhouse gas (GHG emissions from agricultural soils with a high organic matter content. However, the carbon dioxide (CO2 and nitrous oxide (N2O fluxes after afforestation can be considerable, depending predominantly on site drainage and nutrient availability. Studies on the full GHG budget of afforested organic soils are scarce and hampered by the uncertainties associated with methodology. In this study we determined the GHG budget of a spruce-dominated forest on a drained organic soil with an agricultural history. Two different approaches for determining the net ecosystem CO2 exchange (NEE were applied: for the year 2008, direct (eddy covariance and an indirect (analyzing the different components of the GHG budget, so that uncertainties in each method could be evaluated. The annual tree production in 2008 was 8.2 (± 1.7t C ha–1yr–1 due to the high levels of soil nutrients, the favorable climatic conditions and the fact that the forest was in its optimum growth phase. N2O fluxes were determined by the closed chamber technique and amounted to 3.3 (± 2.4 t CO2eq ha–1 yr–1. According to the direct measurements from the eddy covariance technique, the site acts as a minor GHG sink of −4.1 (± 2.6 t CO2eq ha–1 yr–1. This contrasts with the NEE estimate derived from the indirect approach which suggests that the site is a net GHG emitter of 3.3 (± 10.1t CO2eq ha–1 yr–1. Irrespective of the approach applied, the soil CO2 effluxes counter large amounts of the C sequestration by trees. Due to major uncertainties involved in the indirect approach, the direct approach is considered the more reliable tool. As the site was in its optimum growth stage, i.e. the rate of C sequestration was at its maximum and will decrease with forest age, it will probably become a GHG source once again as the trees mature. Since forests in their younger stages are usually GHG sources

  16. Terrestrial Carbon Losses from Mountaintop Coal Mining Offsets Regional Forest Carbon Sequestration in the 21ST Century

    Science.gov (United States)

    Acton, P. M.; Campbell, J. E.; Fox, J.

    2012-12-01

    Studies that quantify the spatial and temporal variability of carbon sources and sinks provide process-level information for predicting future levels of atmospheric carbon dioxide as well as verification of current emission agreements. Assessments of carbon sources and sinks for North America that compare top-down atmospheric constraints with bottom-up inventories find particularly large carbon sinks in the southeastern US. However, this southeastern US sink may be impacted by extreme land-use disturbance events due to mountaintop coal mining (MCM). Here we apply ecosystem modeling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region. For projections based on historical mining rates and the continued regrowth of un-mined forests, we find that the southern Appalachian forests switch from a net carbon sink to a net carbon source by year 2025 to 2033 with a 30% to 35% loss is terrestrial carbon stocks relative to a scenario with no future mining of forest carbon by the year 2100. Alternatively, scenarios of forest sequestration due to the offsetting effects of CO2 fertilization and enhanced soil respiration result in a 15% to 24% loss in terrestrial carbon stocks by the year 2100 for mining scenarios relative to scenarios with no future mining. These results suggest that while stack emissions are the dominant life-cycle in coal-fired electricity, accounting for mountaintop coal mining in bottom-up inventories may be a critical land-use component of regional carbon budgets.

  17. Carbon footprint of milk from sheep farming systems in northern Spain including soil carbon sequestration in grasslands

    DEFF Research Database (Denmark)

    Batalla, Inma M.; Knudsen, Marie Trydeman; Mogensen, Lisbeth;

    2015-01-01

    sequestration in the carbon footprint calculations. Especially in grasslands, soil carbon sequestration might be a potential sink to mitigate greenhouse gas emissions in the livestock sector. However, there is no commonly accepted methodology on how to include soil carbon sequestration in carbon footprint...... calculations. In this study, the carbon footprint of sheep milk was estimated from 12 farms in Northern Spain. Before taken into account contribution from soil carbon sequestration in the calculation, the carbon footprint values varied from 2.0 to 5.2 kg CO2 eq. per kg Fat and Protein Corrected Milk (FPCM...

  18. Experimental microchannel heat sink performance studies using nano-fluids

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Reiyu; Chuang, Jason [Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung City, Taiwan (China)

    2007-01-15

    In this study, microchannel heat sink (MCHS) performance using nano-fluids as coolants is addressed. We first carried out a simple theoretical analysis that indicated more energy and lower MCHS wall temperature could be obtained under the assumption that heat transfer could be enhanced by the presence of nano-particles. Experiments were then performed to verify the theoretical predictions. A silicon MCHS was made and CuO-H{sub 2}O mixtures without a dispersion agent were used as the coolants. The CuO particle volume fraction was in the range of 0.2 to 0.4%. It was found that nano-fluid-cooled MCHS could absorb more energy than water-cooled MCHS when the flow rate was low. For high flow rates, the heat transfer was dominated by the volume flow rate and nano-particles did not contribute to the extra heat absorption. The measured MCHS wall temperature variations agreed with the theoretical prediction for low flow rate. For high flow rate, the measured MCHS wall temperatures did not completely agree with the theoretical prediction due to the particle agglomeration and deposition. It was also found that raising the nano-fluid bulk temperature could prevent the particles from being agglomerated into larger scale particle clusters. The experimental result also indicated that only slightly increase in pressure drop due to the presence of nano-particles in MCHS operation. (author)

  19. The deep sea is a major sink for microplastic debris.

    Science.gov (United States)

    Woodall, Lucy C; Sanchez-Vidal, Anna; Canals, Miquel; Paterson, Gordon L J; Coppock, Rachel; Sleight, Victoria; Calafat, Antonio; Rogers, Alex D; Narayanaswamy, Bhavani E; Thompson, Richard C

    2014-12-01

    Marine debris, mostly consisting of plastic, is a global problem, negatively impacting wildlife, tourism and shipping. However, despite the durability of plastic, and the exponential increase in its production, monitoring data show limited evidence of concomitant increasing concentrations in marine habitats. There appears to be a considerable proportion of the manufactured plastic that is unaccounted for in surveys tracking the fate of environmental plastics. Even the discovery of widespread accumulation of microscopic fragments (microplastics) in oceanic gyres and shallow water sediments is unable to explain the missing fraction. Here, we show that deep-sea sediments are a likely sink for microplastics. Microplastic, in the form of fibres, was up to four orders of magnitude more abundant (per unit volume) in deep-sea sediments from the Atlantic Ocean, Mediterranean Sea and Indian Ocean than in contaminated sea-surface waters. Our results show evidence for a large and hitherto unknown repository of microplastics. The dominance of microfibres points to a previously underreported and unsampled plastic fraction. Given the vastness of the deep sea and the prevalence of microplastics at all sites we investigated, the deep-sea floor appears to provide an answer to the question-where is all the plastic?

  20. The deep sea is a major sink for microplastic debris

    Science.gov (United States)

    Woodall, Lucy C.; Sanchez-Vidal, Anna; Canals, Miquel; Paterson, Gordon L.J.; Coppock, Rachel; Sleight, Victoria; Calafat, Antonio; Rogers, Alex D.; Narayanaswamy, Bhavani E.; Thompson, Richard C.

    2014-01-01

    Marine debris, mostly consisting of plastic, is a global problem, negatively impacting wildlife, tourism and shipping. However, despite the durability of plastic, and the exponential increase in its production, monitoring data show limited evidence of concomitant increasing concentrations in marine habitats. There appears to be a considerable proportion of the manufactured plastic that is unaccounted for in surveys tracking the fate of environmental plastics. Even the discovery of widespread accumulation of microscopic fragments (microplastics) in oceanic gyres and shallow water sediments is unable to explain the missing fraction. Here, we show that deep-sea sediments are a likely sink for microplastics. Microplastic, in the form of fibres, was up to four orders of magnitude more abundant (per unit volume) in deep-sea sediments from the Atlantic Ocean, Mediterranean Sea and Indian Ocean than in contaminated sea-surface waters. Our results show evidence for a large and hitherto unknown repository of microplastics. The dominance of microfibres points to a previously underreported and unsampled plastic fraction. Given the vastness of the deep sea and the prevalence of microplastics at all sites we investigated, the deep-sea floor appears to provide an answer to the question—where is all the plastic? PMID:26064573

  1. Past, growth and persistence of source-sink metapopulations

    CERN Document Server

    Bansaye, Vincent

    2011-01-01

    Source-sink systems are metapopulations of patches that can be of variable habitat quality. They can be seen as graphs, where vertices represent the patches, and the weighted oriented edges give the probability of dispersal from one patch to another. We consider either finite or source-transitive graphs, i.e., graphs that are identical when viewed from a(ny) source. We assume stochastic, individual-based, density-independent reproduction and dispersal. By studying the path of a single random disperser, we are able to display simple criteria for persistence, either necessary and sufficient, or just sufficient. In case of persistence, we characterize the growth rate of the population as well as the asymptotic occupancy frequencies of the line of ascent of a random survivor. Our method allows to decouple the roles of reproduction and dispersal. Finally, we extend our results to the case of periodic or random environments, where some habitats can have variable growth rates, autocorrelated in space and possibly in...

  2. 2014 PGSFR Safety Analysis for Loss of Heat Sink

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, J. H.; Lee, K. L.; Choi, C. W.; Jeong, T. K.; Yoo, J.; Chang, W. P.; Ahn, S. J.; Lee, S. W.; Kang, S. H.; Ha, K. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    KAERI has been developing a conceptual design of the PGSFR (Prototype Gen-4 Sodium-cooled Fast Reactor) with the thermal power of 392.1 MWt, which is the pool type SFR (Sodium-cooled Fast Reactor) with metal fuel. The PGSFR consists of the PHTS (Primary Heat Transport System), the IHTS (Intermediate Heat Transport System), and the DHRS (Decay Heat Removal System). A LOHS (Loss Of Heat Sink) accident has been investigated for a safety evaluation of the PGSFR using the MARS-LMR code. The safety analysis is evaluated by a CDF (Cumulative Damage Function). In case of the LOHS accident, the tentative safety criterion is the CDF of under 0.05. The LOHS accident has been evaluated in the PGSFR using MARS-LMR. The accident was initiated by both of PHTS pump trip. In the results, the CDF was predicted below a tentative safety criterion of 0.05 with a sufficient margin. The DHRS acceptably functioned for removing the core decay heat during long-term cooling period. Furthermore, it has been elucidated that LOHS with LOOP is more conservative than LOHS without LOOP.

  3. Vortex sinks with axial flow: Solution and applications

    Science.gov (United States)

    Shtern, Vladimir; Borissov, Anatoly; Hussain, Fazle

    1997-10-01

    In this paper we develop a new class of analytical solutions of the Navier-Stokes equations and suggest ways to predict and control complex swirling flows. We consider vortex sinks on curved axisymmetric surfaces with an axial flow and obtain a five-parameter solution family that describes a large variety of flow patterns and models fluid motion in a cylindrical can, whirlpools, tornadoes, and cosmic swirling jets. The singularity of these solutions on the flow axis is removed by matching them with swirling jets. The resulting composite solutions describe flows, consisting of up to seven separation regions (recirculatory "bubbles" and vortex rings), and model flows in the Ranque-Hilsch tube, in the meniscus of electrosprays, in vortex breakdown, and in an industrial vortex burner. The analytical solutions allow a clear understanding of how different control parameters affect the flow and guide selection of optimal parameter values for desired flow features. The approach permits extension to swirling flows with heat transfer and chemical reaction, and have the potential of being significantly useful for further detailed investigation by direct or large-eddy numerical simulations as well as laboratory experimentation.

  4. Sinking, wedging, spreading - viscous spreading on a layer of fluid

    Science.gov (United States)

    Bergemann, Nico; Juel, Anne; Heil, Matthias

    2016-11-01

    We study the axisymmetric spreading of a sessile drop on a pre-existing layer of the same fluid in a regime where the drop is sufficiently large so that the spreading is driven by gravity while capillary and inertial effects are negligible. Experiments performed with 5 ml drops and layer thicknesses in the range 0.1 mm drop evolves as R tn , where the spreading exponent n increases with the layer thickness h. Numerical simulations, based on the axisymmetric free-surface Navier-Stokes equations, reveal three distinct spreading regimes depending on the layer thickness. For thick layers the drop sinks into the layer, accompanied by significant flow in the layer. By contrast, for thin layers the layer ahead of the propagating front is at rest and the spreading behaviour resembles that of a gravity-driven drop spreading on a dry substrate. In the intermediate regime the spreading is characterised by an advancing wedge, which is sustained by fluid flow from the drop into the layer.

  5. Estimates of Carbon Sequestration in Tidal Coastal Wetlands Along the US east Coast

    Science.gov (United States)

    Globally, salt marshes are reported to sequester carbon (210 g C m-2 y -1), and along with mangroves in the US, they are reported to account for 1–2 % of the carbon sink for the conterminous US. Using the published salt marsh carbon sequestration rate and National Wetland Invent...

  6. Estimates of Carbon Sequestration and Storage in Tidal Coastal Wetlands Along the US East Coast

    Science.gov (United States)

    Globally, salt marshes are reported to sequester carbon (210 g C m-2 y -1), and along with mangroves in the US, they are reported to account for 1–2 % of the carbon sink for the conterminous US. Using the published salt marsh carbon sequestration rate and National Wetland Invent...

  7. Arbuscular Mycorrhizal Fungi and Glomalin Enhance Carbon Sequestration in Organic Farming Systems

    Science.gov (United States)

    Atmospheric carbon dioxide concentrations have increased nearly 100 ppm in the last 250 years. Soils may be able to mitigate this by sequestering carbon, but agricultural soils are often a source rather than a sink for carbon. The Rodale Institute’s Farming Systems Trial® (FST), initiated in 1981 ...

  8. BIG SKY CARBON SEQUESTRATION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Capalbo

    2005-01-31

    The Big Sky Carbon Sequestration Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts under this Partnership in Phase I fall into four areas: evaluation of sources and carbon sequestration sinks that will be used to determine the location of pilot demonstrations in Phase II; development of GIS-based reporting framework that links with national networks; designing an integrated suite of monitoring, measuring, and verification technologies and assessment frameworks; and initiating a comprehensive education and outreach program. The groundwork is in place to provide an assessment of storage capabilities for CO{sub 2} utilizing the resources found in the Partnership region (both geological and terrestrial sinks), that would complement the ongoing DOE research. Efforts are underway to showcase the architecture of the GIS framework and initial results for sources and sinks. The region has a diverse array of geological formations that could provide storage options for carbon in one or more of its three states. Likewise, initial estimates of terrestrial sinks indicate a vast potential for increasing and maintaining soil C on forested, agricultural, and reclaimed lands. Both options include the potential for offsetting economic benefits to industry and society. Steps have been taken to assure that the GIS-based framework is consistent among types of sinks within the Big Sky Partnership area and with the efforts of other western DOE partnerships. The Partnership recognizes the critical importance of measurement, monitoring, and verification technologies to support not only carbon trading but all policies and programs that DOE and other agencies may want to pursue in support of GHG mitigation. The efforts in developing and implementing MMV technologies for geological sequestration reflect this concern. Research is

  9. Are there "black holes" in carbonate deposystems?

    OpenAIRE

    Wright, V.P.; Cherns, L.

    2009-01-01

    The likelihood that extensive dissolution of aragonite (and high magnesian calcite) takes place during very early burial, even in relatively shallow tropical settings, has wide implications for interpreting and modelling ancient limestones. Some low energy environments may constitute net sinks (“black holes”) for carbonates. If this is the case attempts to model sediment budgets and develop depth-productivity profiles for carbonate systems require as yet unavailable quantitative data on the e...

  10. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen......In 1845, the French chemist and mining engineer Jacques-Joseph Ebelman figured out why Earth's atmosphere contains oxygen (1). Oxygen is produced by plants during photosynthesis, but almost all of this oxygen is used again in respiration. Ebelman reasoned that small amounts of organic matter...

  11. Heat sink design considerations in medium power electronic applications with long power cycles

    CERN Document Server

    AUTHOR|(SzGeCERN)744611; Papastergiou, Konstantinos; Thiringer, Torbjörn; Bongiorno, Massimo

    2015-01-01

    The aim of this work is to investigate the impact of the heat sink thickness and material, as well as, of the convection coefficient of the water cooling system on the power-electronics module thermal stressing. The heat extraction capability of different thicknesses is tested. It is concluded that the thickest heat sink results in marginally lower temperature variation at the junction level compared to the second thickest one. In the thickest heat sink case, the linear dependence of the thermal resistance on the thickness counteracts the benefit of the increased thermal capacitance. The increase in the cooling medium flow rate, which corresponds to an increase in the convection coefficient between the heat sink bottom surface and the water, can be avoided by increasing the thickness of the heat sink. In this way, the energy consumption of the cooling system is reduced. The increase in the flow rate drastically reduces the thermal stressing in the thinnest heat sink case. The increase of the heat sink thickne...

  12. An Energy Efficient Distance-Aware Routing Algorithm with Multiple Mobile Sinks for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2014-08-01

    Full Text Available Traffic patterns in wireless sensor networks (WSNs usually follow a many-to-one model. Sensor nodes close to static sinks will deplete their limited energy more rapidly than other sensors, since they will have more data to forward during multihop transmission. This will cause network partition, isolated nodes and much shortened network lifetime. Thus, how to balance energy consumption for sensor nodes is an important research issue. In recent years, exploiting sink mobility technology in WSNs has attracted much research attention because it can not only improve energy efficiency, but prolong network lifetime. In this paper, we propose an energy efficient distance-aware routing algorithm with multiple mobile sink for WSNs, where sink nodes will move with a certain speed along the network boundary to collect monitored data. We study the influence of multiple mobile sink nodes on energy consumption and network lifetime, and we mainly focus on the selection of mobile sink node number and the selection of parking positions, as well as their impact on performance metrics above. We can see that both mobile sink node number and the selection of parking position have important influence on network performance. Simulation results show that our proposed routing algorithm has better performance than traditional routing ones in terms of energy consumption.

  13. An energy efficient distance-aware routing algorithm with multiple mobile sinks for wireless sensor networks.

    Science.gov (United States)

    Wang, Jin; Li, Bin; Xia, Feng; Kim, Chang-Seob; Kim, Jeong-Uk

    2014-08-18

    Traffic patterns in wireless sensor networks (WSNs) usually follow a many-to-one model. Sensor nodes close to static sinks will deplete their limited energy more rapidly than other sensors, since they will have more data to forward during multihop transmission. This will cause network partition, isolated nodes and much shortened network lifetime. Thus, how to balance energy consumption for sensor nodes is an important research issue. In recent years, exploiting sink mobility technology in WSNs has attracted much research attention because it can not only improve energy efficiency, but prolong network lifetime. In this paper, we propose an energy efficient distance-aware routing algorithm with multiple mobile sink for WSNs, where sink nodes will move with a certain speed along the network boundary to collect monitored data. We study the influence of multiple mobile sink nodes on energy consumption and network lifetime, and we mainly focus on the selection of mobile sink node number and the selection of parking positions, as well as their impact on performance metrics above. We can see that both mobile sink node number and the selection of parking position have important influence on network performance. Simulation results show that our proposed routing algorithm has better performance than traditional routing ones in terms of energy consumption.

  14. Temporal variation in biodeposit organic content and sinking velocity in long-line shellfish culture

    Science.gov (United States)

    Ren, Lihua; Zhang, Jihong

    2016-09-01

    We measured the organic content and sinking velocities of biodeposits from two scallop species ( Chlamys farreri, Patinopecten yessoensis) and abalone ( Haliotis discus hannai) that were cultured on suspended long-lines. Measurements were conducted every two months from April 2010 to February 2011. The shellfish were divided into three size groups (small, middle, and big sizes). At each sample point, we assessed biodeposit organic content, average sinking velocity, the frequency distribution of sinking velocities, and the correlation between organic content and sinking velocity. The organic content of biodeposits varied significantly among months ( Pchange varied among species. Sinking velocities varied significantly, ranging from 1.9 cm/s. The sinking velocities of biodeposits from C. farreri and P. yessoensis were 0.5-1.5 cm/s and from H. discus hannai were <0.7 cm/s. The organic content was significantly negatively correlated to the sinking velocity of biodeposits in C. farreri ( P<0.001) and P. yessoensis ( P<0.05).

  15. Terrestrial carbon losses from mountaintop coal mining offset regional forest carbon sequestration in the 21st century

    Science.gov (United States)

    Campbell, J. Elliott; Fox, James F.; Acton, Peter M.

    2012-12-01

    Studies that quantify the spatial and temporal variability of carbon sources and sinks provide process-level information for the prediction of future levels of atmospheric carbon dioxide as well as verification of current emission agreements. Assessments of carbon sources and sinks for North America that compare top-down atmospheric constraints with bottom-up inventories find particularly large carbon sinks in the southeastern US. However, this southeastern US sink may be impacted by extreme land-use disturbance events due to mountaintop coal mining (MCM). Here we apply ecosystem modeling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region. For projections based on historical mining rates, grassland reclamation, and the continued regrowth of un-mined forests, we find that the southern Appalachian forests switch from a net carbon sink to a net carbon source by year 2025-33 with a 30%-35% loss in terrestrial carbon stocks relative to a scenario with no future mining by the year 2100. Alternatively, scenarios of forest sequestration due to the effect of CO2 fertilization result in a 15%-24% loss in terrestrial carbon stocks by the year 2100 for mining scenarios relative to scenarios with no future mining. These results suggest that while power plant stack emissions are the dominant life-cycle stage in coal-fired electricity, accounting for mountaintop coal mining in bottom-up inventories may be a critical component of regional carbon budgets.

  16. Novel, resistant microalgal polyethers: An important sink of organic carbon in the marine environment?

    Science.gov (United States)

    Gelin, F.; Boogers, I.; Noordeloos, A. A. M.; Damsté, J. S. Sinninghe; Hatcher, P. G.; Leeuw, J. W. de

    1996-04-01

    Five out of seven marine microalgal species investigated were found to biosynthesize nonhydrolysable, mainly aliphatic, biomacromolecules (algaenans). The molecular structure of the algaenan isolated from the microalga Nannochloropsis salina of the class Eustigmatophyceae was determined by solid state 13C NMR spectroscopy, Curie point pyrolysis-gas chromatography-mass spectrometry, and chemical degradations with HI and RuO 4. The structure is predominantly composed of C 28-C 34 linear chains linked by ether bridges. The algaenan isolated from a second eustigmatophyte ( Nannochloropsis sp.) was structurally similar. Algaenans isolated from two chlorophytes also possess a strongly aliphatic nature, as revealed by the dominance of alkenes/alkanes in their pyrolysates. Accordingly, we propose that the aliphatic character of numerous Recent and ancient marine kerogens reflects selectively preserved algaenans and that these algaenans may act as a source of n-alkanes in marine crude oils.

  17. Enrichment Planting in Secondary Forests: a Promising Clean Development Mechanism to Increase Terrestrial Carbon Sinks

    Directory of Open Access Journals (Sweden)

    Alain Paquette

    2009-06-01

    provee un ingreso a las comunidades de países en desarrollo para mantener servicios ambientales. Proponemos un enriquecimiento de plantación cubierta (EP en rastrojos o bosques secundarios utilizando especies de maderas nativas preciosas como alternativa forestal y proyecto de carbono a pequeña escala. Los diferentes aspectos de implementación del A/R-MDL actual están tomados en cuenta. Discutimos la EP en el contexto de investigaciones continuas en la comunidad indígena Ipetí-Emberá en Panamá-Este. En nuestro sitio, el potencia de almacenamiento de carbono para la EP podría ser de 113 Mg C ha-1, lo cual es comparable a otros usos del suelo como plantaciones de teca y bosque primario. Como los rastrojos presentan una alta producción de biomasa, proyectos de carbono con EP podría acumular cantidades grandes de carbono atmosférico mientras se proveen beneficios socio-económicos. Al mismo tiempo EP podría mantener la estructura ecológica del bosque secundario y la biodiversidad promoviendo sinergias entre dos convenios: el de Biodiversidad y el de cambios climáticos.

  18. Nested atmospheric inversion for the terrestrial carbon sources and sinks in China

    NARCIS (Netherlands)

    Jiang, F.; Wang, H.W.; Chen, J.M.; Zhou, L.X.; Ju, W.M.; Peters, W.

    2013-01-01

    In this study, we establish a~nested atmospheric inversion system with a focus on China using the Bayes theory. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and a Hong Kong

  19. Perturbed lignification impacts tree growth in hybrid poplar--a function of sink strength, vascular integrity, and photosynthetic assimilation.

    Science.gov (United States)

    Coleman, Heather D; Samuels, A Lacey; Guy, Robert D; Mansfield, Shawn D

    2008-11-01

    The effects of reductions in cell wall lignin content, manifested by RNA interference suppression of coumaroyl 3'-hydroxylase, on plant growth, water transport, gas exchange, and photosynthesis were evaluated in hybrid poplar trees (Populus alba x grandidentata). The growth characteristics of the reduced lignin trees were significantly impaired, resulting in smaller stems and reduced root biomass when compared to wild-type trees, as well as altered leaf morphology and architecture. The severe inhibition of cell wall lignification produced trees with a collapsed xylem phenotype, resulting in compromised vascular integrity, and displayed reduced hydraulic conductivity and a greater susceptibility to wall failure and cavitation. In the reduced lignin trees, photosynthetic carbon assimilation and stomatal conductance were also greatly reduced, however, shoot xylem pressure potential and carbon isotope discrimination were higher and water-use efficiency was lower, inconsistent with water stress. Reductions in assimilation rate could not be ascribed to increased stomatal limitation. Starch and soluble sugars analysis of leaves revealed that photosynthate was accumulating to high levels, suggesting that the trees with substantially reduced cell wall lignin were not carbon limited and that reductions in sink strength were, instead, limiting photosynthesis.

  20. Sink or Swim: Navigating the Perilous Waters of Promotion and Tenure--What's Diversity Got to Do with It?

    Science.gov (United States)

    Knight, Wanda B.

    2010-01-01

    The "sink-or-swim" ideology is pervasive in the United States society. At research universities, for example, promotion and tenure are institutional waters in which faculty are forced to sink or swim with respect to publishing. Either they publish ("swim") or they perish ("sink"). In throwing faculty overboard, institutions assume that those who…

  1. Sink or Swim: Navigating the Perilous Waters of Promotion and Tenure--What's Diversity Got to Do with It?

    Science.gov (United States)

    Knight, Wanda B.

    2010-01-01

    The "sink-or-swim" ideology is pervasive in the United States society. At research universities, for example, promotion and tenure are institutional waters in which faculty are forced to sink or swim with respect to publishing. Either they publish ("swim") or they perish ("sink"). In throwing faculty overboard,…

  2. Link or sink: a modelling interpretation of the open Baltic biogeochemistry

    Directory of Open Access Journals (Sweden)

    J. W. Baretta

    2004-08-01

    Full Text Available A 1-D model system, consisting of the 1-D version of the Princeton Ocean Model (POM coupled with the European Regional Seas Ecosystem Model (ERSEM has been applied to a sub-basin of the Baltic Proper, the Bornholm basin. The model has been forced with 3h meteorological data for the period 1979-1990, producing a 12-year hindcast validated with datasets from the Baltic Environmental Database for the same period. The model results demonstrate the model to hindcast the time-evolution of the physical structure very well, confirming the view of the open Baltic water column as a three layer system of surface, intermediate and bottom waters. Comparative analyses of modelled hydrochemical components with respect to the independent data have shown that the long-term system behaviour of the model is within the observed ranges. Also primary production processes, deduced from oxygen (oversaturation are hindcast correctly over the entire period and the annual net primary production is within the observed range. The largest mismatch with observations is found in simulating the biogeochemistry of the Baltic intermediate waters. Modifications in the structure of the model (addition of fast-sinking detritus and polysaccharide dynamics have shown that the nutrient dynamics is linked to the quality and dimensions of the organic matter produced in the euphotic zone, highlighting the importance of the residence time of the organic matter within the microbial foodweb in the intermediate waters. Experiments with different scenarios of riverine nutrient loads, assessed in the limits of a 1-D setup, have shown that the external input of organic matter makes the open Baltic model more heterotrophic. The characteristics of the inputs also drive the dynamics of nitrogen in the bottom layers leading either to nitrate accumulation (when the external sources are inorganic, or to coupled nitrification-denitrification (under strong organic inputs. The model indicates the

  3. A rapid transition from ice covered CO2-rich waters to a biologically mediated CO2 sink in the eastern Weddell Gyre

    Directory of Open Access Journals (Sweden)

    W. Geibert

    2008-03-01

    Full Text Available Circumpolar Deep Water (CDW, locally called Warm Deep Water (WDW, enters the Weddell Gyre in the southeast, roughly at 25° E to 30° E. In December~2002 and January 2003} we studied the effect of entrainment of WDW on the fugacity of carbon dioxide (fCO2 and dissolved inorganic carbon (DIC in Weddell Sea surface waters. Ultimately the fCO2 difference across the sea surface drives CO2 air-sea fluxes. Deep CTD sections and surface transects of fCO2 were made along the Prime Meridian, a northwest-southeast section, and along 17° E to 23° E during cruise ANT XX/2 on FS Polarstern. Upward movement and entrainment of WDW into the winter mixed layer had significantly increased DIC and fCO2 below the sea ice along 0° W and 17° E to 23° E, notably in the southern Weddell Gyre. Nonetheless, the ice cover largely prevented outgassing of CO2 to the atmosphere. During and upon melting of the ice, biological activity rapidly reduced surface water fCO2 by up to 100 μatm, thus creating a sink for atmospheric CO2. Despite the tendency of the surfacing WDW to cause CO2 supersaturation, the Weddell Gyre may well be a CO2 sink on an annual basis due to this effective mechanism involving ice cover and ensuing biological fCO2 reduction. Dissolution of calcium carbonate (CaCO3 in melting sea ice may also play a role in this rapid reduction of surface water fCO2. The CO2 source tendency deriving from the upward movement of "pre-industrial" CDW is declining, as atmospheric CO2 levels continue to increase, and thus the CO2 sink of the Weddell Gyre will continue to increase as well (provided the upward movement of WDW does not change significantly.

  4. Hormonal and metabolic regulation of tomato fruit sink activity and yield under salinity

    DEFF Research Database (Denmark)

    Albacete, Alfonso; Cantero-Navarro, Elena; Balibrea, María E.

    2014-01-01

    Salinization of water and soil has a negative impact on tomato (Solanum lycopersicum L.) productivity by reducing growth of sink organs and by inducing senescence in source leaves. It has been hypothesized that yield stability implies the maintenance or increase of sink activity in the reproductive...... on tomato fruit sink activity, growth, and yield: (i) exogenous hormones were applied to plants, and (ii) transgenic plants overexpressing the cell wall invertase (cwInv) gene CIN1 in the fruits and de novo cytokinin (CK) biosynthesis gene IPT in the roots were constructed. Although salinity reduces fruit...

  5. Sources and Sinks: A Stochastic Model of Evolution in Heterogeneous Environments

    Science.gov (United States)

    Hermsen, Rutger; Hwa, Terence

    2010-12-01

    We study evolution driven by spatial heterogeneity in a stochastic model of source-sink ecologies. A sink is a habitat where mortality exceeds reproduction so that a local population persists only due to immigration from a source. Immigrants can, however, adapt to conditions in the sink by mutation. To characterize the adaptation rate, we derive expressions for the first arrival time of adapted mutants. The joint effects of migration, mutation, birth, and death result in two distinct parameter regimes. These results may pertain to the rapid evolution of drug-resistant pathogens and insects.

  6. Thermal effect of a thermoelectric generator on parallel microchannel heat sink

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Rosendahl, Lasse

    2012-01-01

    Thermoelectric generators (TEG) convert heat energy to electrical power by means of semiconductor charge carriers serving as working fluid. In this work, a TEG is applied to a parallel microchannel heat sink. The effect of the inlet plenum arrangement on the laminar flow distribution...... in the channels is considered at a wide range of the pressure drop along the heat sink. The particular focus of this study is geometrical effect of the TEG on the heat transfer characteristics in the micro-heat sink. The hydraulic diameter of the microchannels is 270 μm, and three heat fluxes are applied...

  7. Boiling Delay phenomenon in a Thermosyphon Heat Sink and Its Effect on Device Performance

    Institute of Scientific and Technical Information of China (English)

    WeilinHu; YihuiZhou; 等

    1994-01-01

    A new kind of thermosyphon heat sink has been studied and developed,its peformance being measured.It was found that a remarkable boiling delay phenomenon occurs during its work.The phenomenon is described and explained and its effects on thermoresistance performance at both steady and transient states are discussed.The thermoresistance of this sink is found to be 0.029℃/W at air velocity 5m/s.THis heat sink will satisfy the needs of cooling rectifier diodes and thyristors of rated currents up to 1000 amperes.

  8. Quasi-passive heat sink for high-power laser diodes

    Science.gov (United States)

    Vetrovec, John

    2009-02-01

    We report on a novel heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink uses a liquid coolant flowing at high speed in a miniature closed and sealed loop. Diode waste heat is received at high flux and transferred to environment, coolant fluid, heat pipe, or structure at a reduced flux. When pumping solid-state or alkali vapor lasers, diode wavelength can be electronically tuned to the absorption features of the laser gain medium. This paper presents the heat sink physics, engineering design, performance modeling, and configurations.

  9. Progress in the development of active heat sink for high-power laser diodes

    Science.gov (United States)

    Vetrovec, John; Feeler, Ryan; Bonham, Steve

    2010-02-01

    We report on the development of a novel active heat sink for high-power laser diodes offering unparalleled capacity in high-heat flux handling and temperature control. The heat sink receives diode waste heat at high flux and transfers it at reduced flux to environment, coolant fluid, heat pipe, or structure. Thermal conductance of the heat sink is electronically adjustable, allowing for precise control of diode temperature and the output light wavelength. When pumping solid-state lasers, diode wavelength can be precisely tuned to the absorption features of the laser gain medium. This paper presents the AHS concept, scaling laws, model predictions, and data from initial testing.

  10. Anomalous Sinking of Spheres due to Local Fluidization of Apparently Fixed Powder Beds.

    Science.gov (United States)

    Oshitani, Jun; Sasaki, Toshiki; Tsuji, Takuya; Higashida, Kyohei; Chan, Derek Y C

    2016-02-12

    The sinking of an intruder sphere into a powder bed in the apparently fixed bed regime exhibits complex behavior in the sinking rate and the final depth when the sphere density is close to the powder bed density. Evidence is adduced that the intruder sphere locally fluidizes the apparently fixed powder bed, allowing the formation of voids and percolation bubbles that facilitates spheres to sink slower but deeper than expected. By adjusting the air injection rate and the sphere-to-powder bed density ratio, this phenomenon provides the basis of a sensitive large particle separation mechanism.

  11. Optimization of nanofluid-cooled microchannel heat sink

    Directory of Open Access Journals (Sweden)

    Adham Ahmed Mohammed

    2016-01-01

    Full Text Available The optimization of a nanofluid-cooled rectangular microchannel heat sink is reported. Two nanofluids with volume fraction of 1 %, 3 %, 5 %, 7 % and 9 % are employed to enhance the overall performance of the system. An optimization scheme is applied consisting of a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA-II. The optimized results showed that the increase in the particles volume fraction results in a decrease in the total thermal resistance and an increase in the pumping power. For volume fractions of 1 %, 3 %, 5 %, 7 % and 9 %, the thermal resistances were 0.072, 0.07151, 0.07075, 0.07024 and 0.070 [oK W-1] for the SiC-H2O while, they were 0.0705, 0.0697, 0.0694, 0.0692 and 0.069 [oK W-1] for the TiO2-H2O. The associated pumping power were 0.633, 0.638, 0.704, 0.757 and 0.807 [W] for the SiC-H2O while they were 0.645, 0.675, 0.724, 0.755 and 0.798 [W] for the TiO2-H2O. In addition, for the same operating conditions, the nanofluid-cooled system outperformed the water-cooled system in terms of the total thermal resistance (0.069 and 0.11 for nanofluid-cooled and water-cooled systems, respectively. Based on the results observed in this study, nanofluids should be considered as the future coolant for electronic devices cooling systems.

  12. N-SINK - reduction of waste water nitrogen load

    Science.gov (United States)

    Aalto, Sanni; Tiirola, Marja; Arvola, Lauri; Huotari, Jussi; Tulonen, Tiina; Rissanen, Antti; Nykänen, Hannu

    2014-05-01

    Protection of the Baltic Sea from eutrophication is one of the key topics in the European Union environmental policy. One of the main anthropogenic sources of nitrogen (N) loading into Baltic Sea are waste water treatment plants, which are currently capable in removing only 40-70% of N. European commission has obliged Finland and other Baltic states to reduce nitrate load, which would require high monetary investments on nitrate removal processes in treatment plants. In addition, forced denitrification in treatment plants would increase emissions of strong greenhouse gas N2O. In this project (LIFE12 FI/ENV/597 N-SINK) we will develop and demonstrate a novel economically feasible method for nitrogen removal using applied ecosystem services. As sediment is known to have enormous capacity to reduce nitrate to nitrogen gas through denitrification, we predict that spatial optimization of the waste water discharge would be an efficient way to reduce nitrate-based load in aquatic systems. A new sediment filtration approach, which will increase both the area and time that nitrified waste water will be in contact with the reducing microbes of the sediment, is tested. Compared to the currently implemented practice, where purified waste water is discharged though one-point outlet system, we expect that sediment filtration system will result in more efficient denitrification and decreased N load to aquatic system. We will conduct three full-scale demonstrations in the receiving water bodies of waste water treatment plants in Southern and Central Finland. The ecosystem effects of sediment filtration system will be monitored. Using the most advanced stable isotope techniques will allow us accurately measure denitrification and unfavoured DNRA (reduction of nitrite to ammonium) activity.

  13. Gully catchment as sediment sinks, not just a source

    Science.gov (United States)

    Larsen, Annegret; Heckmann, Tobias; Larsen, Joshua; Bork, Hans-Rudolf

    2016-04-01

    Catchment wide sediment fluxes have been modified throughout the Anthropocene, but it`s spatial and temporal dimension is still under debate. Here, we present a long-term sediment budget, highlighting the overlooked role of gullies as significant sediment sinks, and challenging the prevalent view of gullies as being exclusively conveyor belts of sediment. This is important, as sediment delivery from hillslopes to trunk streams represents a significant pathway of mass transfer in the landscape, with a large fraction facilitated by gully systems. In this study, we analysed the sediment mass balance and storage dynamics within a headwater gully catchment in central Europe over the last ~12 500 yrs. Human induced erosion resulted in hillslope erosion rates ~2.3 times higher than under naturally de-vegetated conditions during the Younger Dryas. However the total sediment inputs to the gully system (and therefore gully aggradation), were similar. Net gully storage has consistently increased to become the second largest term in the sediment budget after hillslope erosion (storage is ~45% and ~73% of inputs during two separate erosion and aggradation cycles). In terms of the depletion of gully sediment storage, the sediment mass balance shows that export beyond the gully fan was not significant until the last ~500 years, due to reduced gully fan accommodation space. The significance of storage effects on the gully sediment mass balance, particularly the export terms, means that it would be difficult to determine the influences of human impact and / or climatic changes from floodplain or lake sedimentary archives alone and that the sediment budgets of the headwater catchments from which they drain are more likely to provide these mechanistic links.

  14. A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings.

    Science.gov (United States)

    Klopotek, Yvonne; Franken, Philipp; Klaering, Hans-Peter; Fischer, Kerstin; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

    2016-02-01

    The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation.

  15. Potential Carbon Negative Commercial Aviation through Land Management

    Science.gov (United States)

    Hendricks, Robert C.

    2008-01-01

    Brazilian terra preta soil and char-enhanced soil agricultural systems have demonstrated both enhanced plant biomass and crop yield and functions as a carbon sink. Similar carbon sinking has been demonstrated for both glycophyte and halophyte plants and plant roots. Within the assumption of 3.7 t-C/ha/yr soils and plant root carbon sinking, it is possible to provide carbon neutral U.S. commercial aviation using about 8.5% of U.S. arable lands. The total airline CO2 release would be offset by carbon credits for properly managed soils and plant rooting, becoming carbon neutral for carbon sequestered synjet processing. If these lands were also used to produce biomass fuel crops such as soybeans at an increased yield of 60 bu/acre (225gal/ha), they would provide over 3.15 10(exp 9) gallons biodiesel fuel. If all this fuel were refined into biojet it would provide a 16% biojet-84% synjet blend. This allows the U.S. aviation industry to become carbon negative (carbon negative commercial aviation through carbon credits). Arid land recovery could yield even greater benefits.

  16. National inventory report 1990-2009: greenhouse gas sourcesand sinks in Canada - The Canadian Government's submission to the UN Framework Convention on Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This document is the national inventory report for 1990 to 2009 on greenhouse gas sources and sinks in Canada. Herein is provided an inventory of the emissions of greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrogen dioxide (NO2), hydrofluorocarbon (HFCs), perfluorocarbon (PFCs), and sulphur hexafluoride (SF6) by the energy, industrial and agricultural sectors in Canada for every year between 1990 and 2009. An analysis of every Canadian province and territory in terms of electricity consumption and greenhouse gas emissions is then provided. Finally, an inventory of greenhouse gas emissions, electricity generation and greenhouse gas intensity is provided for the years 1990 and 2000 to 2009.

  17. Historical carbon dioxide emissions caused by land-use changes are possibly larger than assumed

    Science.gov (United States)

    Arneth, A.; Sitch, S.; Pongratz, J.; Stocker, B. D.; Ciais, P.; Poulter, B.; Bayer, A. D.; Bondeau, A.; Calle, L.; Chini, L. P.; Gasser, T.; Fader, M.; Friedlingstein, P.; Kato, E.; Li, W.; Lindeskog, M.; Nabel, J. E. M. S.; Pugh, T. A. M.; Robertson, E.; Viovy, N.; Yue, C.; Zaehle, S.

    2017-01-01

    The terrestrial biosphere absorbs about 20% of fossil-fuel CO2 emissions. The overall magnitude of this sink is constrained by the difference between emissions, the rate of increase in atmospheric CO2 concentrations, and the ocean sink. However, the land sink is actually composed of two largely counteracting fluxes that are poorly quantified: fluxes from land-use change and CO2 uptake by terrestrial ecosystems. Dynamic global vegetation model simulations suggest that CO2 emissions from land-use change have been substantially underestimated because processes such as tree harvesting and land clearing from shifting cultivation have not been considered. As the overall terrestrial sink is constrained, a larger net flux as a result of land-use change implies that terrestrial uptake of CO2 is also larger, and that terrestrial ecosystems might have greater potential to sequester carbon in the future. Consequently, reforestation projects and efforts to avoid further deforestation could represent important mitigation pathways, with co-benefits for biodiversity. It is unclear whether a larger land carbon sink can be reconciled with our current understanding of terrestrial carbon cycling. Our possible underestimation of the historical residual terrestrial carbon sink adds further uncertainty to our capacity to predict the future of terrestrial carbon uptake and losses.

  18. Workshop on assessments of National Carbon Budgets within the Nordic Region

    DEFF Research Database (Denmark)

    Mørk, Eva Thorborg; Lansø, Anne Sofie; Hansen, Kristina;

    2013-01-01

    research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... is formed from. This report summarizes presentations and discussions from the four thematic sessions; Observations of carbon sinks and sources, Modeling the carbon budget, Remote sensing data for carbon modeling, and Impacts of future climate and land use scenarios and gives an overview of the current...

  19. Workshop on assessments of National Carbon Budgets within the Nordic Region

    DEFF Research Database (Denmark)

    Hansen, Kristina; Koyama, Aki; Lansø, Anne Sofie;

    research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... is formed from. This report summarizes presentations and discussions from the four thematic sessions; Observations of carbon sinks and sources, Modeling the carbon budget, Remote sensing data for carbon modeling, and Impacts of future climate and land use scenarios and gives an overview of the current...

  20. China’s Forests and Their Impact on Global Carbon Cycle

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Forests have multiple benefits and functions, including mitigation of climate change. The impacts of forests on the global carbon cycle include forests as carbon sinks, wood-based products as carbon sinks, bio-energy, and production and use of non-timber products. In the past decades, forest cover of China has increased from 8.6% to 18.21% by large-scale afforestation and conversion of cropland into forests. Forest biomass carbon (C) stock increased from 4.3 Pg C (1 Pg C = 1 015 g C) in the early 1980s to 5...

  1. Big Sky Carbon Sequestration Partnership

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Capalbo

    2005-11-01

    The Big Sky Carbon Sequestration Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts under this Partnership in Phase I fall into four areas: evaluation of sources and carbon sequestration sinks that will be used to determine the location of pilot demonstrations in Phase II; development of GIS-based reporting framework that links with national networks; designing an integrated suite of monitoring, measuring, and verification technologies and assessment frameworks; and initiating a comprehensive education and outreach program. The groundwork is in place to provide an assessment of storage capabilities for CO2 utilizing the resources found in the Partnership region (both geological and terrestrial sinks), that would complement the ongoing DOE research agenda in Carbon Sequestration. The region has a diverse array of geological formations that could provide storage options for carbon in one or more of its three states. Likewise, initial estimates of terrestrial sinks indicate a vast potential for increasing and maintaining soil C on forested, agricultural, and reclaimed lands. Both options include the potential for offsetting economic benefits to industry and society. Steps have been taken to assure that the GIS-based framework is consistent among types of sinks within the Big Sky Partnership area and with the efforts of other DOE regional partnerships. The Partnership recognizes the critical importance of measurement, monitoring, and verification technologies to support not only carbon trading but all policies and programs that DOE and other agencies may want to pursue in support of GHG mitigation. The efforts in developing and implementing MMV technologies for geological sequestration reflect this concern. Research is also underway to identify and validate best management practices for soil C in the

  2. BIG SKY CARBON SEQUESTRATION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Capalbo

    2004-10-31

    The Big Sky Carbon Sequestration Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts under this Partnership fall into four areas: evaluation of sources and carbon sequestration sinks; development of GIS-based reporting framework; designing an integrated suite of monitoring, measuring, and verification technologies; and initiating a comprehensive education and outreach program. At the first two Partnership meetings the groundwork was put in place to provide an assessment of capture and storage capabilities for CO{sub 2} utilizing the resources found in the Partnership region (both geological and terrestrial sinks), that would complement the ongoing DOE research. During the third quarter, planning efforts are underway for the next Partnership meeting which will showcase the architecture of the GIS framework and initial results for sources and sinks, discuss the methods and analysis underway for assessing geological and terrestrial sequestration potentials. The meeting will conclude with an ASME workshop. The region has a diverse array of geological formations that could provide storage options for carbon in one or more of its three states. Likewise, initial estimates of terrestrial sinks indicate a vast potential for increasing and maintaining soil C on forested, agricultural, and reclaimed lands. Both options include the potential for offsetting economic benefits to industry and society. Steps have been taken to assure that the GIS-based framework is consistent among types of sinks within the Big Sky Partnership area and with the efforts of other western DOE partnerships. Efforts are also being made to find funding to include Wyoming in the coverage areas for both geological and terrestrial sinks and sources. The Partnership recognizes the critical importance of measurement, monitoring, and verification

  3. Anthropogenic perturbation of the global carbon cycle as a result of agricultural carbon erosion and burial

    Science.gov (United States)

    Wang, Zhengang; Govers, Gerard; Kaplan, Jed; Hoffmann, Thomas; Doetterl, Sebastian; Six, Johan; Van Oost, Kristof

    2016-04-01

    Changes in terrestrial carbon storage exert a strong control over atmospheric CO2 concentrations but the underlying mechanisms are not fully constrained. Anthropogenic land cover change is considered to represent an important carbon loss mechanism, but current assessments do not consider the associated acceleration of carbon erosion and burial in sediments. We evaluated the role of anthropogenic soil erosion and the resulting carbon fluxes between land and atmosphere from the onset of agriculture to the present day. We show, here, that agricultural erosion induced a significant cumulative net uptake of 198±57 Pg carbon on terrestrial ecosystems. This erosion-induced soil carbon sink is estimated to have offset 74±21% of carbon emissions. Since 1850, erosion fluxes have increased 3-fold. As a result, the erosion and lateral transfer of organic carbon in relation to human activities is an important driver of the global carbon cycle at millennial timescales.

  4. Evaluation of carbon fluxes and trends (2000-2008) in the Greater Platte River Basin: a sustainability study on the potential biofuel feedstock development

    Science.gov (United States)

    Gu, Yingxin; Wylie, Bruce K.; Zhang, Li; Gilmanov, Tagir G.

    2012-01-01

    This study evaluates the carbon fluxes and trends and examines the environmental sustainability (e.g., carbon budget, source or sink) of the potential biofuel feedstock sites identified in the Greater Platte River Basin (GPRB). A 9-year (2000–2008) time series of net ecosystem production (NEP), a measure of net carbon absorption or emission by ecosystems, was used to assess the historical trends and budgets of carbon flux for grasslands in the GPRB. The spatially averaged annual NEP (ANEP) for grassland areas that are possibly suitable for biofuel expansion (productive grasslands) was 71–169 g C m−2 year−1 during 2000–2008, indicating a carbon sink (more carbon is absorbed than released) in these areas. The spatially averaged ANEP for areas not suitable for biofuel feedstock development (less productive or degraded grasslands) was −47 to 69 g C m−2 year−1 during 2000–2008, showing a weak carbon source or a weak carbon sink (carbon emitted is nearly equal to carbon absorbed). The 9-year pre-harvest cumulative ANEP was 1166 g C m−2 for the suitable areas (a strong carbon sink) and 200 g C m−2 for the non-suitable areas (a weak carbon sink). Results demonstrate and confirm that our method of dynamic modeling of ecosystem performance can successfully identify areas desirable and sustainable for future biofuel feedstock development. This study provides useful information for land managers and decision makers to make optimal land use decisions regarding biofuel feedstock development and sustainability.

  5. 77 FR 46717 - Drawn Stainless Steel Sinks From the People's Republic of China: Preliminary Affirmative...

    Science.gov (United States)

    2012-08-06

    ... with fabricated bowls may sometimes be referred to as ``zero radius'' or ``near zero radius'' sinks... us to reject the strength of governance as a determinant of interest rates. As confirmed by...

  6. Butte Sink Wildlife Management Area [1989:Land Status Map: Sheet 1 of 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This map was produced by the Division of Realty to depict landownership at Butte Sink Wildlife Management Area. It was generated from rectified aerial photography,...

  7. Nanofluid jet impingement heat transfer characteristics in the rectangular mini-fin heat sink

    Science.gov (United States)

    Naphon, Paisarn; Nakharintr, Lursukd

    2012-11-01

    The nanofluid jet impingement heat transfer characteristics in a rectangular mini-fin heat sink are studied. The heat sink is fabricated from aluminum by a wire electrical discharge machine. The nanofluid is a mixture of deionized water and nanoscale TiO2 particles with a volume nanoparticle concentration of 0.2%. The results obtained for nanofluid jet impingement cooling in the rectangular mini-fin heat sink are compared with those found in the water jet impingement cooling. The effects of the inlet temperature of the nanofluid, its Reynolds number, and the heat flux on the heat transfer characteristics of the rectangular mini-fin heat sink are considered. It is found that the average heat transfer rates for the nanofluid as coolant are higher than those for deionized water.

  8. Optimization of the thermal performance of multi-layer silicon microchannel heat sinks

    Directory of Open Access Journals (Sweden)

    Xu Shanglong

    2016-01-01

    Full Text Available The objective is to optimize the configuration sizes and thermal performance of a multilayer silicon microchannel heat sink by the thermal resistance network model. The effect of structural parameter on the thermal resistance is analyzed by numercal simulation. Taking the thermal resistance as an objective function, a nonlinear and multi-constrained optimization model are proposed for the silicon microchannel heat sink in electronic chips cooling. The sequential quadratic programming (SQP method is used to do the optimization design of the configuration sizes of the microchannel. For the heat sink with the size of 20mm×20mm and the power of 400 W, the optimized microchannel number, layer, height and width are 40 and 2, 2.2mm and 0.2mm, respectively, and its corresponding total thermal resistance for whole microchannel heat sink is 0.0424 K/W.

  9. HEAT TRANSFER ENHANCEMENT OF SMALL SCALE HEAT SINKS USING VIBRATING PIN FIN

    Directory of Open Access Journals (Sweden)

    Suabsakul Gururatana

    2013-01-01

    Full Text Available Heat sinks are widely adopted in electronics cooling together with different technologies to enhance the cooling process. For the small electronics application, the small scale pin fins heat sinks are extensively used to dissipate heat in electronics devices. Due to the limit of space in the small devices, it is impossible to increase heat transfer area. In order to improve the heat transfer performance, the applying the forced vibration is one of challenging method. This study applies the vibration frequency between 50 to 1,000 Hz to pin fins heat sinks. The results of numerical simulation clearly show satisfied heat transfer augmentation. However, the Pressure drop significantly increases with frequency. This phenomenon affects the heat transfer enhancement performance that it increases with frequency until certain value then it drops rapidly. The results of this study can help designing heat sinks for electronics cooling by employing the concept of vibration.

  10. Non-random walk diffusion enhances the sink strength of semicoherent interfaces

    Science.gov (United States)

    Vattré, A.; Jourdan, T.; Ding, H.; Marinica, M.-C.; Demkowicz, M. J.

    2016-01-01

    Clean, safe and economical nuclear energy requires new materials capable of withstanding severe radiation damage. One strategy of imparting radiation resistance to solids is to incorporate into them a high density of solid-phase interfaces capable of absorbing and annihilating radiation-induced defects. Here we show that elastic interactions between point defects and semicoherent interfaces lead to a marked enhancement in interface sink strength. Our conclusions stem from simulations that integrate first principles, object kinetic Monte Carlo and anisotropic elasticity calculations. Surprisingly, the enhancement in sink strength is not due primarily to increased thermodynamic driving forces, but rather to reduced defect migration barriers, which induce a preferential drift of defects towards interfaces. The sink strength enhancement is highly sensitive to the detailed character of interfacial stresses, suggesting that `super-sink' interfaces may be designed by optimizing interface stress fields. Such interfaces may be used to create materials with unprecedented resistance to radiation-induced damage.

  11. A net-jet flow system for mass transfer and microsensor studies of sinking aggregates

    DEFF Research Database (Denmark)

    Ploug, H.; Jørgensen, BB

    1999-01-01

    was shown to be laminar at flow velocities ranging from 40 to 200 m d(-1), which cover typical sinking velocities of aggregates in the ocean. A viscous boundary layer with steep gradients of flow velocity was measured around sinking aggregates by flow visualization techniques. Velocity gradients......A flow system was developed which enables studies of hydrodynamics and mass transfer in freely sinking aggregates. The aggregates stabilized their positions in the water phase at an upward flow Velocity which balanced and opposed the sinking velocity of the individual aggregate. The flow field...... in the viscous boundary layer along the sides of the aggregate parallel to the flow could by explained by creeping flow, while a non-turbulent wake was present at the rear (downstream) of the aggregate. The oxygen distribution inside a ca 3.5 mm large diatom aggregate and in the surrounding water was mapped in 2...

  12. A molecular-genetic approach to studying source-sink interactions in Arabidopsis thalian. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, S. I.

    2000-06-01

    This is a final report describing the results of the research funded by the DOE Energy Biosciences Program grant entitled ''A Molecular-Genetic Approach to Studying Source-Sink Interactions in Arabidiopsis thaliana''.

  13. CTE-Matched, Liquid-Cooled, High Thermal Conductivity Heat Sink Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of a CTE-matched, liquid-cooled, high thermal conductivity heat sink for use in spacecraft thermal management applications. The material...

  14. Dynamics of carbon storage in the woody biomass of northern forests

    Science.gov (United States)

    Dong, Jiarui

    2002-09-01

    Part of the puzzle of greenhouse gases and climate change is determining where carbon dioxide (CO2) is absorbed, and what causes a region to become a "carbon sink". Analyses of atmospheric CO2 concentration changes indicate a carbon sink of about 1 to 2 billion tons on land in the northerly regions. Elsewhere the land is suggested to be neutral, which implies that emissions of another 1.5 billion tons of carbon a year from cutting and burning of tropical forests are nearly balanced by sinks of similar magnitude there. The geographical detail of the land carbon sink has, however, remained elusive. Forest greenness observations from sensors on National Oceanic and Atmospheric Administration satellites were combined with wood volume data from forest inventories to produce relatively high resolution maps of carbon stocks in about 15 million square kilometers of northern forests, roughly above the 30th parallel. Comparison of carbon stock maps from the late 1990s and early 1980s identifies where forests were storing carbon and where they were losing carbon. Results indicate that about 61 billion tons of carbon is contained in the wood of these northern forests. Further, the analysis indicates that forests in Europe, Russia and America have been storing nearly 700 million metric tons of carbon a year, or about 12% of annual global carbon emissions from industrial activities, during the 1980s and 1990s. American forests absorbed 120 million tons of carbon a year, which is about 11% of the USA's annual emissions. With the exception of some Canadian boreal forests, which were found to be losing carbon, most northern forests were storing carbon. Russia, the country with the most forests, accounted for almost 40 percent of the biomass carbon sink. This study has important scientific, economic and policy implications. The scientific implication is that it deconstructs the mystery of the land carbon sink by providing geographically detailed maps of forest carbon pools, sources

  15. Intracellular Nitrate of Marine Diatoms as a Driver of Anaerobic Nitrogen Cycling in Sinking Aggregates

    Directory of Open Access Journals (Sweden)

    Anja Kamp

    2016-11-01

    Full Text Available Diatom-bacteria aggregates are key for the vertical transport of organic carbon in the ocean. Sinking aggregates also represent pelagic microniches with intensified microbial activity, oxygen depletion in the center, and anaerobic nitrogen cycling. Since some of the aggregate-forming diatom species store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom-bacteria aggregates. Stable 15N isotope incubations under dark and anoxic conditions revealed that axenic S. marinoi is able to reduce intracellular nitrate to ammonium that is immediately excreted by the cells. When exposed to a light:dark cycle and oxic conditions, S. marinoi stored nitrate intracellularly in concentrations > 60 mmol L-1 both as free-living cells and associated to aggregates. Intracellular nitrate concentrations exceeded extracellular concentrations by three orders of magnitude. Intracellular nitrate was used up within 2-3 days after shifting diatom-bacteria aggregates to dark and anoxic conditions. Thirty-one percent of the diatom-derived nitrate was converted to nitrogen gas, indicating that a substantial fraction of the intracellular nitrate pool of S. marinoi becomes available to the aggregate-associated bacterial community. Only 5% of the intracellular nitrate was reduced to ammonium, while 59% was recovered as nitrite. Hence, aggregate-associated diatoms accumulate nitrate from the surrounding water and sustain complex nitrogen transformations, including loss of fixed nitrogen, in anoxic, pelagic microniches. Additionally, it may be expected that intracellular nitrate not converted before the aggregates have settled onto the seafloor could fuel benthic nitrogen transformations.

  16. Observations of total RONO2 over the boreal forest: NOx sinks and HNO3 sources

    Directory of Open Access Journals (Sweden)

    E. C. Browne

    2013-05-01

    Full Text Available In contrast with the textbook view of remote chemistry where HNO3 formation is the primary sink of nitrogen oxides, recent theoretical analyses show that formation of RONO2 (ΣANs from isoprene and other terpene precursors is the primary net chemical loss of nitrogen oxides over the remote continents where the concentration of nitrogen oxides is low. This then increases the prominence of questions concerning the chemical lifetime and ultimate fate of ΣANs. We present observations of nitrogen oxides and organic molecules collected over the Canadian boreal forest during the summer which show that ΣANs account for ~20% of total oxidized nitrogen and that their instantaneous production rate is larger than that of HNO3. This confirms the primary role of reactions producing ΣANs as a control over the lifetime of NOx (NOx = NO + NO2 in remote, continental environments. However, HNO3 is generally present in larger concentrations than ΣANs indicating that the atmospheric lifetime of ΣANs is shorter than the HNO3 lifetime. We investigate a range of proposed loss mechanisms that would explain the inferred lifetime of ΣANs finding that in combination with deposition, two processes are consistent with the observations: (1 rapid ozonolysis of isoprene nitrates where at least ~40% of the ozonolysis products release NOx from the carbon backbone and/or (2 hydrolysis of particulate organic nitrates with HNO3 as a product. Implications of these ideas for our understanding of NOx and NOy budget in remote and rural locations are discussed.

  17. Observations of total RONO2 over the boreal forest: NOx sinks and HNO3 sources

    Directory of Open Access Journals (Sweden)

    P. O. Wennberg

    2013-01-01

    Full Text Available In contrast with the textbook view of remote chemistry where HNO3 formation is the primary sink of nitrogen oxides, recent theoretical analyses show that formation of RONO2 (ΣANs from isoprene and other terpene precursors is the primary net chemical loss of nitrogen oxides over the remote continents where the concentration of nitrogen oxides is low. This then increases the prominence of questions concerning the chemical lifetime and ultimate fate of ΣANs. We present observations of nitrogen oxides and organic molecules collected over the Canadian boreal forest during the summer that show that ΣANs account for ~ 20% of total oxidized nitrogen and that their instantaneous production rate is larger than that of HNO3. This confirms the primary role of reactions producing ΣANs as a control over the lifetime of NOx (NOx = NO + NO2 in remote, continental environments. However, HNO3 is generally present in larger concentrations than ΣANs indicating that the atmospheric lifetime of ΣANs is shorter than the HNO3 lifetime. We investigate a range of proposed loss mechanisms that would explain the inferred lifetime of ΣANs finding that in combination with deposition, two processes are consistent with the observations: (1 rapid ozonolysis of isoprene nitrates where at least ~ 40% of the ozonolysis products release NOx from the carbon backbone and/or (2 hydrolysis of particulate organic nitrates with HNO3 as a product. Implications of these ideas for our understanding of NOx and NOy budget in remote and rural locations are discussed.

  18. Observations of total RONO2 over the boreal forest: NOx sinks and HNO3 sources

    Science.gov (United States)

    Browne, E. C.; Min, K.-E.; Wooldridge, P. J.; Apel, E.; Blake, D. R.; Brune, W. H.; Cantrell, C. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Weinheimer, A. J.; Wennberg, P. O.; Wisthaler, A.; Cohen, R. C.

    2013-05-01

    In contrast with the textbook view of remote chemistry where HNO3 formation is the primary sink of nitrogen oxides, recent theoretical analyses show that formation of RONO2 (ΣANs) from isoprene and other terpene precursors is the primary net chemical loss of nitrogen oxides over the remote continents where the concentration of nitrogen oxides is low. This then increases the prominence of questions concerning the chemical lifetime and ultimate fate of ΣANs. We present observations of nitrogen oxides and organic molecules collected over the Canadian boreal forest during the summer which show that ΣANs account for ~20% of total oxidized nitrogen and that their instantaneous production rate is larger than that of HNO3. This confirms the primary role of reactions producing ΣANs as a control over the lifetime of NOx (NOx = NO + NO2) in remote, continental environments. However, HNO3 is generally present in larger concentrations than ΣANs indicating that the atmospheric lifetime of ΣANs is shorter than the HNO3 lifetime. We investigate a range of proposed loss mechanisms that would explain the inferred lifetime of ΣANs finding that in combination with deposition, two processes are consistent with the observations: (1) rapid ozonolysis of isoprene nitrates where at least ~40% of the ozonolysis products release NOx from the carbon backbone and/or (2) hydrolysis of particulate organic nitrates with HNO3 as a product. Implications of these ideas for our understanding of NOx and NOy budget in remote and rural locations are discussed.

  19. Sources and sinks of carbonyl sulfide in an agricultural field in the Southern Great Plains.

    Science.gov (United States)

    Maseyk, Kadmiel; Berry, Joseph A; Billesbach, Dave; Campbell, John Elliott; Torn, Margaret S; Zahniser, Mark; Seibt, Ulli

    2014-06-24

    Net photosynthesis is the largest single flux in the global carbon cycle, but controls over its variability are poorly understood because there is no direct way of measuring it at the ecosystem scale. We report observations of ecosystem carbonyl sulfide (COS) and CO2 fluxes that resolve key gaps in an emerging framework for using concurrent COS and CO2 measurements to quantify terrestrial gross primary productivity. At a wheat field in Oklahoma we found that in the peak growing season the flux-weighted leaf relative uptake of COS and CO2 during photosynthesis was 1.3, at the lower end of values from laboratory studies, and varied systematically with light. Due to nocturnal stomatal conductance, COS uptake by vegetation continued at night, contributing a large fraction (29%) of daily net ecosystem COS fluxes. In comparison, the contribution of soil fluxes was small (1-6%) during the peak growing season. Upland soils are usually considered sinks of COS. In contrast, the well-aerated soil at the site switched from COS uptake to emissions at a soil temperature of around 15 °C. We observed COS production from the roots of wheat and other species and COS uptake by root-free soil up to a soil temperature of around 25 °C. Our dataset demonstrates that vegetation uptake is the dominant ecosystem COS flux in the peak growing season, providing support of COS as an independent tracer of terrestrial photosynthesis. However, the observation that ecosystems may become a COS source at high temperature needs to be considered in global modeling studies.

  20. Sources and sinks separating domains of left- and right-traveling waves Experiment versus amplitude equations

    CERN Document Server

    Alvarez, R; Van Saarloos, W; Alvarez, Roberto; Hecke, Martin van; Saarloos, Wim van

    1996-01-01

    In many pattern forming systems that exhibit traveling waves, sources and sinks occur which separate patches of oppositely traveling waves. We show that simple qualitative features of their dynamics can be compared to predictions from coupled amplitude equations. In heated wire convection experiments, we find a discrepancy between the observed multiplicity of sources and theoretical predictions. The expression for the observed motion of sinks is incompatible with any amplitude equation description.

  1. Shifts in metabolic hydrogen sinks in the methanogenesis-inhibited ruminal fermentation: a meta-analysis

    OpenAIRE

    Emilio M. Ungerfeld

    2015-01-01

    Maximizing the flow of metabolic hydrogen ([H]) in the rumen away from CH4 and towards volatile fatty acids (VFA) would increase the efficiency of ruminant production and decrease its environmental impact. The objectives of this meta-analysis were: i) To quantify shifts in metabolic hydrogen sinks when inhibiting ruminal methanogenesis in vitro; and ii) To understand the variation in shifts of metabolic hydrogen sinks among experiments and between batch and continuous cultures systems when me...

  2. Enhanced Three Tier Security Architecture for WSN Against Mobile Sink Replication Attacks Using Mutual Authentication Scheme

    Directory of Open Access Journals (Sweden)

    Linciya.T

    2013-05-01

    Full Text Available Recent developments on Wireless Sensor Networks have made their application in a wide range such as military sensing and tracking, health monitoring, traffic monitoring, video surveillance and so on.Wireless sensor nodes are restricted to computational resources, and are always deployed in a harsh,unattended or unfriendly environment. Therefore, network security becomes a tough task and it involves the authorization of admittance to data in a network. The problem of authentication and pair wise keyestablishment in sensor networks with mobile sink is still not solved in the mobile sink replication attacks.In q-composite key pre distribution scheme, a large number of keys are compromised by capturing a small fraction of sensor nodes by the attacker. Theattacker can easily take a control of the entire network by deploying a replicated mobile sinks. Those mobile sinks which are preloaded with compromised keys are used authenticate and initiate data communication with sensor node. To determine the above problem the system adduces the three-tier security framework for authentication and pair wise key establishmentbetween mobile sinks and sensor nodes. The previous system used the polynomial key pre distribution scheme for the sensor networks which handles sink mobility and continuous data delivery to the neighbouring nodes and sinks, but this scheme makeshigh computational cost and reduces the life time of sensors. In order to overcome this problem a random pair wise key pre distribution scheme is suggested and further it helps to improve the network resilience. In addition to this an Identity Based Encryption is used to encrypt the data and Mutual authentication scheme is proposed for the identification and isolation of replicated mobile sink from the network.

  3. Reconstructing source-sink dynamics in a population with a pelagic dispersal phase.

    Directory of Open Access Journals (Sweden)

    Kun Chen

    Full Text Available For many organisms, the reconstruction of source-sink dynamics is hampered by limited knowledge of the spatial assemblage of either the source or sink components or lack of information on the strength of the linkage for any source-sink pair. In the case of marine species with a pelagic dispersal phase, these problems may be mitigated through the use of particle drift simulations based on an ocean circulation model. However, when simulated particle trajectories do not intersect sampling sites, the corroboration of model drift simulations with field data is hampered. Here, we apply a new statistical approach for reconstructing source-sink dynamics that overcomes the aforementioned problems. Our research is motivated by the need for understanding observed changes in jellyfish distributions in the eastern Bering Sea since 1990. By contrasting the source-sink dynamics reconstructed with data from the pre-1990 period with that from the post-1990 period, it appears that changes in jellyfish distribution resulted from the combined effects of higher jellyfish productivity and longer dispersal of jellyfish resulting from a shift in the ocean circulation starting in 1991. A sensitivity analysis suggests that the source-sink reconstruction is robust to typical systematic and random errors in the ocean circulation model driving the particle drift simulations. The jellyfish analysis illustrates that new insights can be gained by studying structural changes in source-sink dynamics. The proposed approach is applicable for the spatial source-sink reconstruction of other species and even abiotic processes, such as sediment transport.

  4. Effect of precipitate-matrix interface sinks on the growth of voids in the matrix

    Energy Technology Data Exchange (ETDEWEB)

    Brailsford, A.D.; Mansur, L.K.

    1981-01-01

    A qualitative discussion of the differing roles played by coherent and incoherent precipitates as point defect sinks is presented. Rate theory is used to obtain semiquantitative estimates of the growth of cavities in the matrix when either type of precipitate is present. Methods for deriving the sink strengths of precipitates of arbitrary shape are developed. In three materials where available microstructural information allows an analysis, precipitates are found to cause only a small relative suppression of cavity growth via the mechanisms here considered.

  5. Heat transfer interface between a high temperature heat source and a heat sink

    Energy Technology Data Exchange (ETDEWEB)

    du Pre, F.K.; Jaspers, H.A.

    1977-10-11

    A heat-transfer interface between and separating a high temperature heat source and a heat sink is formed by the adjacent walls of the heat source and heat sink with a thin gap between these walls and helium gas sealed in the gap, the walls preferably defining concentric hemispheres; this interface being particularly feasible as separable walls of the heater portion of a Stirling engine and a heat source.

  6. A Swarm Intelligent Algorithm Based Route Maintaining Protocol for Mobile Sink Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xiaoming Wu

    2015-01-01

    Full Text Available Recent studies have shown that mobile sink can be a solution to solve the problem that energy consumption of sensor nodes is not balanced in wireless sensor networks (WSNs. Caused by the sink mobility, the paths between the sensor nodes and the sink change frequently and have profound influence on the lifetime of WSN. It is necessary to design a protocol that can find efficient routings between the mobile sink and nodes but does not consume too many network resources. In this paper, we propose a swarm intelligent algorithm based route maintaining protocol to resolve this issue. The protocol utilizes the concentric ring mechanism to guide the route researching direction and adopts the optimal routing selection to maintain the data delivery route in mobile sink WSN. Using the immune based artificial bee colony (IABC algorithm to optimize the forwarding path, the routing maintaining protocol could find an alternative routing path quickly and efficiently when the coordinate of sink is changed in WSN. The results of our extensive experiments demonstrate that our proposed route maintaining protocol is able to balance the network traffic load and prolong the network lifetime.

  7. Programming Saposin-Mediated Compensatory Metabolic Sinks for Enhanced Ubiquinone Production.

    Science.gov (United States)

    Xu, Wen; Yuan, Jifeng; Yang, Shuiyun; Ching, Chi-Bun; Liu, Jiankang

    2016-12-16

    Microbial synthesis of ubiquinone by fermentation processes has been emerging in recent years. However, as ubiquinone is a primary metabolite that is tightly regulated by the host central metabolism, tweaking the individual pathway components could only result in a marginal improvement on the ubiquinone production. Given that ubiquinone is stored in the lipid bilayer, we hypothesized that introducing additional metabolic sink for storing ubiquinone might improve the CoQ10 production. As human lipid binding/transfer protein saposin B (hSapB) was reported to extract ubiquinone from the lipid bilayer and form the water-soluble complex, hSapB was chosen to build a compensatory metabolic sink for the ubiquinone storage. As a proof-of-concept, hSapB-mediated metabolic sink systems were devised and systematically investigated in the model organism of Escherichia coli. The hSapB-mediated periplasmic sink resulted in more than 200% improvement of CoQ8 over the wild type strain. Further investigation revealed that hSapB-mediated sink systems could also improve the CoQ10 production in a CoQ10-hyperproducing E. coli strain obtained by a modular pathway rewiring approach. As the design principles and the engineering strategies reported here are generalizable to other microbes, compensatory sink systems will be a method of significant interest to the synthetic biology community.

  8. Changes in seed weight in response to different sources: sink ratio in oilseed rape

    Directory of Open Access Journals (Sweden)

    Francisco M Iglesias

    2014-06-01

    Full Text Available Little knowledge exists about the degree of source, sink and source: sink limitations on mean seed weight in oilseed rape (Brassica napus L.. The objective of this work was to analyze the nature and magnitude on seed weight response to assimilate availability during the effective seed-filling period in oilseed rape. Three Argentinean varieties, Eclipse, Impulse, and Master, were grown under field conditions, and at the beginning of the effective seed filling period, a broad range of source: sink manipulation combinations were produced. Source manipulations consisted of two incoming radiation (R level reductions: 0% (Rn and ~50% (Rs combined with three different sources: sink treatments were applied: C, control; PR, ~50% pod removal, and D, 100% defoliation. Rs significantly reduced yield (15% and MSW (12% with respect to Rn, without significant effects on the rest of the sub yield components. Source:sink manipulation treatments significantly affected all yield components. PR diminished yield by 29%, reducing ca. 40% seeds pl-1 by reductions pods pl-1 (41% with respect to Rn, whereas PR increased MSW by 19%, counterbalancing the reduction in seeds pl-1 and thereby in yield. When considering different seed positions along the main raceme, Rs reduced MSW by 12% independently of seed positions onto the raceme. On the contrary, PR increased MSW in average 17% with respect to C. Results reported here suggest that oilseed rape has source: sink co-limitation during the effective seed filling period, which is apparently higher than wheat and lower than maize.

  9. Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol.

    Science.gov (United States)

    Brown, Sandra; Swingland, Ian R; Hanbury-Tenison, Robin; Prance, Ghillean T; Myers, Norman

    2002-08-15

    The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means to absorb or reduce emissions of CO(2) (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions, and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social, environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals.

  10. Kyoto protocol: analysis of options for further development of commitments for the second commitment period. Part ''sinks in the second commitment period''; Kyoto-Protokoll: Untersuchung von Optionen fuer die Weiterentwicklung der Verpflichtungen fuer die 2. Verpflichtungsperiode. Teilvorhaben ''Senken in der 2. Verpflichtungsperiode''

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Ernst-Detlef; Freibauer, Annette [Max-Planck-Institut fuer Biogeochemie, Jena (Germany); Matthes, Felix Christian; Herold, Anke [Oeko-Institut, Berlin (Germany); Wouters, Frank; Hoehne, Niklas [ECOFYS GmbH, Koeln (Germany)

    2007-03-15

    The project aimed at developing and analysing options for commitments in a future climate regime with focus on land use, land use change and forestry (LULUCF). Based on experiences from the past international negotiations and the implementation of the United Nations Framework Convention on Climate Change (UNFCCC), options for core rules were described and analysed according to a catalogue of criteria for environmental and and political success. A literature review, own calculations and a model developed in the frame of the project for calculating forest management effects on carbon stock changes in biomass, soil and wood products were used to quantitatively determine the potential carbon sources and sinks by afforestation, deforestation, forestry and agricultural management in important countries and globally for the next decades, up to one century. The results show that forest management determines the future role of the LULUCF sector in Annex-I countries. The magnitude of future carbon sinks is driven by the age structure of the forests and follows region specific trends. Emissions from deforestation in Non-Annex-I countries exceed by far the potential carbon sinks in managed forests of Annex-I countries. It will be essential for future negotiations to clarify first the accounting rules for carbon sources and sinks in agriculture, forests and other land uses and the relation between the LULUCF sector and other sectors before quantitative emission limitation targets are set. This is even more important in light of a potential integration of emission reductions from deforestation and degradation in a future carbon trading scheme. Experiences with the past national greenhouse gas inventories under the UNFCCC demonstrate that the LULUCF sector could in the future be treated in the same way as the other sectors. National trends in carbon sources and sinks in forests and from deforestation and degradation need to be considered when future emission limitation targets

  11. BIG SKY CARBON SEQUESTRATION PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Capalbo

    2004-06-01

    The Big Sky Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts during the second performance period fall into four areas: evaluation of sources and carbon sequestration sinks; development of GIS-based reporting framework; designing an integrated suite of monitoring, measuring, and verification technologies; and initiating a comprehensive education and outreach program. At the first two Partnership meetings the groundwork was put in place to provide an assessment of capture and storage capabilities for CO{sub 2} utilizing the resources found in the Partnership region (both geological and terrestrial sinks), that would complement the ongoing DOE research. The region has a diverse array of geological formations that could provide storage options for carbon in one or more of its three states. Likewise, initial estimates of terrestrial sinks indicate a vast potential for increasing and maintaining soil C on forested, agricultural, and reclaimed lands. Both options include the potential for offsetting economic benefits to industry and society. Steps have been taken to assure that the GIS-based framework is consistent among types of sinks within the Big Sky Partnership area and with the efforts of other western DOE partnerships. Efforts are also being made to find funding to include Wyoming in the coverage areas for both geological and terrestrial sinks and sources. The Partnership recognizes the critical importance of measurement, monitoring, and verification technologies to support not only carbon trading but all policies and programs that DOE and other agencies may want to pursue in support of GHG mitigation. The efforts begun in developing and implementing MMV technologies for geological sequestration reflect this concern. Research is also underway to identify and validate best management practices for

  12. The Airborne Carbon in the Mountains Experiment

    Science.gov (United States)

    Schimel, D.; Stephens, B.; Running, S.; Monson, R.; Vukicevic, T.; Ojima, D.

    2004-12-01

    Mountain landscapes of the Western US contain a significant portion of the North American carbon sink. This results from the land use history of the region, which has a preponderance of potentially aggrading mid-aged stands. The issue is significant not only because of the significant sink but because of the vulnerability of that sink to drought, insects, wildfire and other ecological changes occurring rapidly in the West. Quantification of the carbon budgets of western forests have received relatively limited attention, in part because direct carbon flux measurements are believed to be difficult to apply in complex landscapes. New techniques that take advantage of organized nighttime drainage flows may allow quantification of respiration on scales inaccessible in level landscapes, while Lagrangian airborne measurements may allow daytime fluxes to be quantified. Airborne and ground-based measurements during the summer of 2004 in Colorado show substantial drawdown of atmospheric carbon dioxide during the day and strong enrichment of the nocturnal boundary layer from nighttime respiration. We present a strategy whereby in situ measurements at multiple scales, remote sensing and data assimilation may be used to quantify carbon dynamics in mountain landscapes. Larger scales of integration may be possible in mountainous than level landscapes because of the integrative flow of air and water, while because of high heterogeneity, scaling from detailed local process studies remains difficult.

  13. Terrestrial Carbon Cycle Variability

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    detected trends in global primary productivity are even smaller (33 Tg-C y -2). Yet residual carbon balance methods infer that the terrestrial biosphere is experiencing a significant and growing carbon sink. Possible explanations for this large and growing net land sink include roles of land use change and greening of the land, regional enhancement of photosynthesis, and down regulation of plant and soil respiration with warming temperatures. Longer time series of variables needed to provide top-down and bottom-up assessments of the carbon cycle are needed to resolve these pressing and unresolved issues regarding how, why, and at what rates gross and net carbon fluxes are changing. PMID:27746899

  14. Carbon emission and sequestration of urban turfgrass systems in Hong Kong.

    Science.gov (United States)

    Kong, Ling; Shi, Zhengjun; Chu, L M

    2014-03-01

    Climate change is more than just a global issue. Locally released carbon dioxide may lead to a rise in global ambient temperature and influence the surrounding climate. Urban greenery may mitigate this as they can remove carbon dioxide by storing carbon in substrates and vegetation. On the other hand, urban greenery systems which are under intense management and maintenance may contribute to the emission of carbon dioxide or other greenhouse gases. The impact of urban greenery on carbon balance in major metropolitan areas thus remains controversial. We investigated the carbon footprints of urban turf operation and maintenance by conducting a research questionnaire on different Hong Kong turfs in 2012, and showed that turf maintenance contributed 0.17 to 0.63 kg Ce m(-2)y(-1) to carbon emissions. We also determined the carbon storage of turfs at 0.05 to 0.21 kg C m(-2) for aboveground grass biomass and 1.26 to 4.89 kg C m(-2) for soils (to 15 cm depth). We estimated that the carbon sink capacity of turfs could be offset by carbon emissions in 5-24 years under current management patterns, shifting from carbon sink to carbon source. Our study suggested that maintenance management played a key role in the carbon budget and footprint of urban greeneries. The environmental impact of turfgrass systems can be optimized by shifting away from empirically designed maintenance schedules towards rational ones based on carbon sink and emission principles.

  15. Integrating plant carbon dynamics with mutualism ecology.

    Science.gov (United States)

    Pringle, Elizabeth G

    2016-04-01

    Plants reward microbial and animal mutualists with carbohydrates to obtain nutrients, defense, pollination, and dispersal. Under a fixed carbon budget, plants must allocate carbon to their mutualists at the expense of allocation to growth, reproduction, or storage. Such carbon trade-offs are indirectly expressed when a plant exhibits reduced growth or fecundity in the presence of its mutualist. Because carbon regulates the costs of all plant mutualisms, carbon dynamics are a common platform for integrating these costs in the face of ecological complexity and context dependence. The ecophysiology of whole-plant carbon allocation could thus elucidate the ecology and evolution of plant mutualisms. If mutualisms are costly to plants, then they must be important but frequently underestimated sinks in the terrestrial carbon cycle.

  16. [Forest carbon storage and fuel carbon emission in Tanjiang River basin].

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