WorldWideScience

Sample records for belowground carbon allocation

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

    Science.gov (United States)

    Christian P. Giardina; Michael G. Ryan

    2002-01-01

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

  2. THE EFFECT OF OZONE ON BELOW-GROUND CARBON ALLOCATION IN WHEAT

    Science.gov (United States)

    Short term 14CO2 pulse and chase experiments were conducted in order to investigate the effect ozone on below-ground carbon allocation in spring wheat seedlings (Triticum aestivumL. ?ANZA'). Wheat seedlings were grown in a sand-hydroponic system and exposed to either high ozone ...

  3. Nitrogen fertilization decouples roots and microbes: Reductions in belowground carbon allocation limit microbial activity

    Science.gov (United States)

    Carrara, J.; Walter, C. A.; Govindarajulu, R.; Hawkins, J.; Brzostek, E. R.

    2017-12-01

    Nitrogen (N) deposition has enhanced the ability of trees to capture atmospheric carbon (C). The effect of elevated N on belowground C cycling, however, is variable and response mechanisms are largely unknown. Recent research has highlighted distinct differences between ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees in the strength of root-microbial interactions. In particular, ECM trees send more C to rhizosphere microbes to stimulate enzyme activity and nutrient mobilization than AM trees, which primarily rely on saprotrophic microbes to mobilize N. As such, we hypothesized that N fertilization would weaken root-microbial interactions and soil decomposition in ECM stands more than in AM stands. To test this hypothesis, we measured root-microbial interactions in ECM and AM plots in two long-term N fertilization studies, the Fernow Experimental Forest, WV and Bear Brook Watershed, ME. We found that N fertilization led to declines in plant C allocation belowground to fine root biomass, branching, and root exudation in ECM stands to a greater extent than in AM stands. As ECM roots are tightly coupled to the soil microbiome through energy and nutrient exchange, reductions in belowground C allocation were mirrored by shifts in microbial community composition and reductions in fungal gene expression. These shifts were accompanied by larger reductions in fungal-derived lignolytic and hydrolytic enzyme activity in ECM stands than in AM stands. In contrast, as the AM soil microbiome is less reliant on trees for C and are more adapted to high inorganic nutrient environments, the soil metagenome and transcriptome were more resilient to decreases in belowground C allocation. Collectively, our results indicate the N fertilization decoupled root-microbial interactions by reducing belowground carbon allocation in ECM stands. Thus, N fertilization may reduce soil turnover and increase soil C storage to a greater extent in forests dominated by ECM than AM trees.

  4. Carbon allocation belowground in Pinus pinaster using stable carbon isotope pulse labeling technique

    Science.gov (United States)

    Dannoura, M.; Bosc, A.; Chipeaux, C.; Sartore, M.; Lambrot, C.; Trichet, P.; Bakker, M.; Loustau, D.; Epron, D.

    2010-12-01

    Carbon allocation belowground competes with aboveground growth and biomass production. In the other hand, it contributes to resource acquisition such as nutrient, water and carbon sequestration in soil. Thus, a better characterization of carbon flow from plant to soil and its residence time within each compartment is an important issue for understanding and modeling forest ecosystem carbon budget. 13C pulse labeling of whole crown was conducted at 4 seasons to study the fate of assimilated carbon by photosynthesis into the root on 12 year old Pinus pinaster planted in the INRA domain of Pierroton. Maritime pine is the most widely planted species in South-West Europe. Stem, root and soil CO2 effluxes and their isotope composition were measured continuously by tunable diode laser absorption spectroscopy with a trace gas analyzer (TGA 100A; Campbell Scientific) coupled to flow-through chambers. 13CO2 recovery and peak were observed in respiration of each compartment after labeling. It appeared sequentially from top of stem to bottom, and to coarse root. The maximum velocity of carbon transfer was calculated as the difference in time lag of recovery between two positions on the trunk or on the root. It ranged between 0.08-0.2 m h-1 in stem and between 0.04-0.12 m h-1 in coarse root. This velocity was higher in warmer season, and the difference between time lag of recovery and peak increased after first frost. Photosynthates arrived underground 1.5 to 5 days after labeling, at similar time in soil CO2 effluxes and coarse root respiration. 0.08-1.4 g of carbon was respired per tree during first 20 days following labeling. It presented 0.6 -10% of 13C used for labeling and it is strongly related to seasons. The isotope signal was detected in fine root organs and microbial biomass by periodical core sampling. The peak was observed 6 days after labeling in early summer while it was delayed more than 10 days in autumn and winter with less amount of carbon allocated

  5. Aboveground tree growth varies with belowground carbon allocation in a tropical rainforest environment

    Science.gov (United States)

    J.W. Raich; D.A. Clark; L. Schwendenmann; Tana Wood

    2014-01-01

    Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the...

  6. Belowground Carbon Allocation to Ectomycorrhizal Fungi Links Biogeochemical Cycles of Boron and Nitrogen

    Science.gov (United States)

    Lucas, R. W.; Högberg, P.; Ingri, J. N.

    2011-12-01

    Boron (B) is an essential micronutrient to most trees and represents an important limiting resource in some regions, deficient trees experiencing the loss of apical dominance, altered stem growth, and even tree death in extreme cases. Similar to the acquisition of most soil nutrients, B is likely supplied to host trees by mycorrhizal symbionts in exchange for recently fixed carbohydrates. In this way, belowground allocation of photosynthate, which drives the majority of biological processes belowground, links the biogeochemical cycles of B and nitrogen (N). Using a long-term N addition experiment in a Pinus sylvestris forest that has been ongoing for 41 years, we examined how the availability of inorganic N mediates the response of B isotopes in the tree needles, organic soil, and fungal pools in a boreal forest in northern Sweden. Using archived needle samples collected annually from the current year's needle crop, we observed δ11B to increase from 30.8 (0.5 se) to 41.8 (0.7 se)% in N fertilized plots from 1970 to 1979, a period of increasing B deficiency stress induced by N fertilization; the concentration of B in tree needles during 1979 dropping as low as 3.0 μg g-2. During the same period, B concentrations in tree needles from control plots remained relatively unchanged and δ11B remained at a steady state value of 34.1 (1.0 se)%. Following a distinct, large-scale, pulse labeling event in 1980 in which 2.5 kg ha-1 of isotopically distinct B was applied to all treatment and control plots to alleviate the N-induced B deficiency, concentrations of B in current needles increased immediately in all treatments, the magnitude of the response being dependent upon the N treatment. But unlike other pool dilution studies, δ11B of current tree needles did not return to pre-addition, steady-state levels. Instead, δ11B continued to decrease over time in both N addition and control treatments. This unexpected pattern has not been previously described but can be explained

  7. Belowground Carbon Allocation and Plant-Microbial Interactions Drive Resistance and Resilience of Mountain Grassland Communities to Drought

    Science.gov (United States)

    Karlowsky, S.; Augusti, A.; Ingrisch, J.; Hasibeder, R.; Lavorel, S.; Bahn, M.; Gleixner, G.

    2016-12-01

    Belowground carbon allocation (BCA) and plant-microbial interactions are crucial for the functioning of terrestrial ecosystems. Recent research suggests that extreme events can have severe effects on these processes but it is unknown how land use intensity potentially modifies their responses. We studied the resistance and resilience of mountain grassland communities to prolonged drought and investigated the role of plant C allocation and soil microbial communities in mediating drought resistance and immediate recovery. In a common garden experiment we exposed monoliths from an abandoned grassland and a hay meadow to an early summer drought. Two independent 13C pulse labeling experiments were conducted, the first during peak drought and the second during the recovery phase. The 13C incorporation was analyzed in above- and belowground plant parts and in phospho- and neutral lipid fatty acids of soil microorganisms. In addition, a 15N label was added at the rewetting to determine plant N uptake. We found that C uptake, BCA and C transfer to soil microorganisms were less strongly reduced by drought in the abandoned grassland than in the meadow. Moreover, drought induced an increase of arbuscular mycorrhiza fungi (AMF) marker in the abandoned grassland. Nevertheless, C uptake and related parameters were quickly recovered and N uptake increased in the meadow during recovery. Unexpectedly, AMF and their C uptake were generally reduced during recovery, while bacteria increased and quickly recovered C uptake, particularly in the meadow. Our results showed a negative relation between high resistance and fast recovery. The more resistant abandoned grassland plant communities seemed to invest more C below ground and into interactions with AMF during drought, likely to access water through their hyphal network. Conversely, meadow communities invested more C from recent photosynthesis into bacterial communities during recovery, obviously to gain more nutrients for regrowth

  8. Changes in carbon allocation to aboveground versus belowground forest components is driven by a trade-off involving mycorrhizal fungi, not fine roots

    Science.gov (United States)

    Ouimette, A.; Ollinger, S. V.; Hobbie, E. A.; Lepine, L. C.; Stephens, R.; Rowe, R.; Vadeboncoeur, M. A.; Tumber-Davila, S. J.

    2017-12-01

    Species composition and resource availability exert a strong influence on the dynamics of carbon allocation among different forest ecosystem components. Recent work in temperate forests has highlighted a tradeoff between carbon allocation to aboveground woody tissues (access to light), and belowground to fine roots (access to soil nutrients). Although root-associated mycorrhizal fungi are crucial for N acquisition and can receive 20% or more of annual net primary production, most studies fail to explicitly include carbon allocation to mycorrhizal fungi. In part, this is due to the inherent difficulties in accurately quantifying fungal production. We took several approaches to quantify production of mycorrhizal fungi, including a carbon budget approach and isotopic techniques. Here we present data on patterns of carbon allocation to aboveground (wood and foliar production), and belowground components (production of fine roots and mycorrhizal fungi), across temperate forest stands spanning a range of nitrogen availability and species composition. We found that as the proportion of conifer species decreased, and stand nitrogen availability increased, both the absolute amount and the fraction of net primary production increased for foliage, aboveground wood, and fine roots ("a rising tide lifts all boats"). While allocation to plant pools increased, allocation to mycorrhizal fungi significantly decreased with decreasing conifer dominance and increasing soil nitrogen availability. We did not find a strong trade-off between carbon allocation to fine roots and aboveground wood or foliage. Instead, a negative relationship is seen between allocation to mycorrhizal fungi and other plant pools. Effort to estimate carbon allocation to mycorrhizal fungi is important for gaining a more complete understanding of how ecosystems respond to changes in growth-limiting resources.

  9. Assessing the Significance of Above- and Belowground Carbon Allocation of Fast- and Slow-Growing Families of Loblolly Pine - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Topa, M. A.; Weinstein, D. A.; Retzlaff, W. A.

    2001-03-01

    During this project we experimentally evaluated the below-ground biomass and carbon allocation and partitioning of four different fast- and slow-growing families of loblolly pine located in Scotland County, NC, in an effort to increase the long-term performance of the crop. The trees were subjected to optimal nutrition and control since planting in 1993. Destructive harvests in 1998 and 2000 were used for whole?plant biomass estimates and to identify possible family differences in carbon acquisition (photosynthesis) and water use efficiency. At regular intervals throughout each year we sampled tissues for carbohydrate analyses to assess differences in whole-tree carbon storage. Mini rhizotron observation tubes were installed to monitor root system production and turnover. Stable isotope analysis was used to examine possible functional differences in water and nutrient acquisition of root systems between the various families. A genetic dissection of root ontogenic and architectural traits, including biomass partitioning, was conducted using molecular markers to better understand the functional implications of these traits on resource acquisition and whole-plant carbon allocation.

  10. Above- and Belowground Biomass Allocation in Shrub Biomes across the Northeast Tibetan Plateau

    Science.gov (United States)

    Yang, Yuanhe; Yang, Lucun; Zhou, Guoying

    2016-01-01

    Biomass partitioning has been explored across various biomes. However, the strategies of allocation in plants still remain contentious. This study investigated allocation patterns of above- and belowground biomass at the community level, using biomass survey from the Tibetan Plateau. We explored above- and belowground biomass by conducting three consecutive sampling campaigns across shrub biomes on the northeast Tibetan Plateau during 2011–2013. We then documented the above-ground biomass (AGB), below-ground biomass (BGB) and root: shoot ratio (R/S) and the relationships between R/S and environment factors using data from 201 plots surveyed from 67 sites. We further examined relationships between above-ground and below-ground biomass across various shrub types. Our results indicated that the median values of AGB, BGB, and R/S in Tibetan shrub were 1102.55, 874.91 g m-2, and 0.85, respectively. R/S showed significant trend with mean annual precipitation (MAP), while decreased with mean annual temperature (MAT). Reduced major axis analysis indicated that the slope of the log-log relationship between above- and belowground biomass revealed a significant difference from 1.0 over space, supporting the optimal hypothesis. Interestingly, the slopes of the allometric relationship between log AGB and log BGB differed significantly between alpine and desert shrub. Our findings supported the optimal theory of above- and belowground biomass partitioning in Tibetan shrub, while the isometric hypothesis for alpine shrub at the community level. PMID:27119379

  11. Potential remobilization of belowground permafrost carbon under future global warming

    Science.gov (United States)

    P. Kuhry; E. Dorrepaal; G. Hugelius; E.A.G. Schuur; C. Tarnocai

    2010-01-01

    Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available...

  12. Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe

    OpenAIRE

    Ma, L.; Guo, C.; Xin, X.; Yuan, S.; Wang, R.

    2013-01-01

    Soil carbon (C) and nitrogen (N) cycling are sensitive to changes in environmental factors and play critical roles in the responses of terrestrial ecosystems to natural and anthropogenic perturbations. This study was conducted to quantify the effects of belowground particulate litter (BPL) addition, increased precipitation and their interactions on soil C and N mineralization in two adjacent sites where belowground photosynthate allocation was manipulated through vegetation ...

  13. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Directory of Open Access Journals (Sweden)

    Sebastian Doetterl

    Full Text Available African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors.Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock were only half compared to an area with lower tree height (= smaller aboveground carbon stock. This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system.We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  14. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Science.gov (United States)

    Doetterl, Sebastian; Kearsley, Elizabeth; Bauters, Marijn; Hufkens, Koen; Lisingo, Janvier; Baert, Geert; Verbeeck, Hans; Boeckx, Pascal

    2015-01-01

    African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors. Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock) were only half compared to an area with lower tree height (= smaller aboveground carbon stock). This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system. We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  15. Carbon allocation in forest ecosystems

    Science.gov (United States)

    Creighton M. Litton; James W. Raich; Michael G. Ryan

    2007-01-01

    Carbon allocation plays a critical role in forest ecosystem carbon cycling. We reviewed existing literature and compiled annual carbon budgets for forest ecosystems to test a series of hypotheses addressing the patterns, plasticity, and limits of three components of allocation: biomass, the amount of material present; flux, the flow of carbon to a component per unit...

  16. Production and carbon allocation in a clonal Eucalyptus plantation with water and nutrient manipulations

    Science.gov (United States)

    Jose Luiz Stape; Dan Binkley; Michael G. Ryan

    2008-01-01

    We examined resource limitations on growth and carbon allocation in a fast-growing, clonal plantation of Eucalyptus grandis urophylla in Brazil by characterizing responses to annual rainfall, and response to irrigation and fertililization for 2 years. Productivity measures included gross primary production (GPP), total belowground carbon allocation (...

  17. Belowground Carbon Cycling Processes at the Molecular Scale: An EMSL Science Theme Advisory Panel Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy J.; Brown, Gordon E.; Plata, Charity

    2014-02-21

    As part of the Belowground Carbon Cycling Processes at the Molecular Scale workshop, an EMSL Science Theme Advisory Panel meeting held in February 2013, attendees discussed critical biogeochemical processes that regulate carbon cycling in soil. The meeting attendees determined that as a national scientific user facility, EMSL can provide the tools and expertise needed to elucidate the molecular foundation that underlies mechanistic descriptions of biogeochemical processes that control carbon allocation and fluxes at the terrestrial/atmospheric interface in landscape and regional climate models. Consequently, the workshop's goal was to identify the science gaps that hinder either development of mechanistic description of critical processes or their accurate representation in climate models. In part, this report offers recommendations for future EMSL activities in this research area. The workshop was co-chaired by Dr. Nancy Hess (EMSL) and Dr. Gordon Brown (Stanford University).

  18. Carbon Storage and Allocation Pattern in Plant Biomass among Different Forest Plantation Stands in Guangdong, China

    OpenAIRE

    Chen, Yuanqi; Liu, Zhanfeng; Rao, Xingquan; Wang, Xiaoling; Liang, Chenfei; Lin, Yongbiao; Zhou, Lixia; Cai, Xi-an; Fu, Shenglei

    2015-01-01

    In order to understand how carbon storage and allocation patterns vary among plantation types, we estimated carbon allocation between above- and below-ground compartments in four subtropical plantations and a naturally recovered shrubland (as a control). Results indicated that the carbon storage and allocation pattern varied greatly among forest types and was highly dependent on specific traits of trees and understory vegetation. The fast-growing species, such as Eucalyptus urophylla, accumul...

  19. Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

    International Nuclear Information System (INIS)

    Risio, Lucia; Herrero, Celia; Bogino, Stella M.; Bravo, Felipe

    2014-01-01

    The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2 A dj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha −1 . While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased. - Highlights: • A model for estimating aboveground and belowground Prosopis caldenia biomass was developed. • Biomass allocation into the tree and the root/shoot ratio were analyzed. • The equation systems presented had made it possible to more accurately estimate the biomass stored in calden woodlands

  20. Altered belowground carbon cycling following land use change to perennial bioenergy crops

    Science.gov (United States)

    Belowground carbon (C) dynamics of terrestrial ecosystems play an important role in the global C cycle and thereby in climate regulation, yet remain poorly understood. Globally, land use change is a major driver of changes in belowground C storage; in general, land clearing and tillage for agricult...

  1. Changes in Soil Carbon Stocks and Fluxes in Response to Altered Above- and Belowground Vegetation Inputs

    Science.gov (United States)

    Marañón-Jiménez, S.; Schuetze, C.; Cuntz, M.; García-Quirós, I.; Dienstbach, L.; Schrumpf, M.; Rebmann, C.

    2016-12-01

    The stimulation of vegetation productivity in response to rising atmospheric CO2 concentrations can potentially compensate climate change feedbacks. However, this will depend on the allocation of C resources of vegetation into biomass production versus root exudates and on the feedbacks with soil microorganisms. These dynamic adjustments of vegetation will result on changes in above- and belowground productivity and on the amount of C exported to root exudates. Consequent alteration of litter and rhizosphere detritus inputs to the soil and their interaction on controlling soil C sequestration capacity has been, however, rarely assessed. We hypothesize that above- and belowground vegetation exert a synergistic control of soil CO2 emissions, and that the activation of soil organic matter mineralization by the addition of labile organic substrates (i.e.: the priming effect) is altered by changes in the amount and in the quality of the carbon inputs. In order to elucidate these questions, different levels of litter addition were implemented on trenched (root exclusion) and non-trenched plots (with roots) in a temperate deciduous forest. Changes in the sensitivity of soil respiration to temperature and moisture were detected by measuring CO2 fluxes continuously at high temporal resolution with automatic chambers, whereas the spatial and seasonal variability was determined using portable chambers. Annual changes in soil carbon and nitrogen stocks provide additional information on the soil carbon sequestration in response to above- and belowground inputs. Both roots and litter inputs significantly enhanced soil CO2 effluxes soon after the implementation of the experiment. We detected synergistic effects between roots and litter inputs on soil CO2 emissions: When roots were present, carbon mineralized in response to litter addition was much higher than the total amount of carbon added in litter (ca. 170 g C m-2 y-1). Preliminary results of this study suggest that labile

  2. First Assessment of Carbon Stock in the Belowground Biomass of Brazilian Mangroves

    Directory of Open Access Journals (Sweden)

    DANIEL M.C. SANTOS

    2017-08-01

    Full Text Available ABSTRACT Studies on belowground roots biomass have increasingly reported the importance of the contribution of this compartment in carbon stock maintenance in mangrove forests. To date, there are no estimates of this contribution in Brazilian mangrove forests, although the country has the second largest area of mangroves worldwide. For this study, trenches dug in fringing forests in Guaratiba State Biological Reserve (Rio de Janeiro, Brazil were used to evaluate the contribution of the different classes of roots and the vertical stratification of carbon stock. The total carbon stock average in belowground roots biomass in these forests was 104.41 ± 20.73 tC.ha−1. From that, an average of 84.13 ± 21.34 tC.ha−1 corresponded to the carbon stock only in fine roots, which have diameters smaller than 5 mm and are responsible for over 80% of the total belowground biomass. Most of the belowground carbon stock is concentrated in the first 40 cm below the surface (about 70%. The root:shoot ratio in this study is 1.14. These estimates demonstrate that the belowground roots biomass significantly contributes, more than 50%, to the carbon stock in mangrove forests. And the mangrove root biomass can be greater than that of other Brazilian ecosystems.

  3. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi

    Czech Academy of Sciences Publication Activity Database

    Slavíková, R.; Püschel, David; Janoušková, Martina; Hujslová, M.; Konvalinková, T.; Gryndlerová, H.; Gryndler, M.; Weiser, M.; Jansa, J.

    2017-01-01

    Roč. 27, č. 1 (2017), s. 35-51 ISSN 0940-6360 Institutional support: RVO:67985939 Keywords : belowground carbon allocation * 13C isotope labelling * Medicago truncatula * Glomeromycota * shade * Rhizophagus irregularis Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.047, year: 2016

  4. Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

    Science.gov (United States)

    Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

    2017-12-01

    The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

  5. Carbon Storage and Allocation Pattern in Plant Biomass among Different Forest Plantation Stands in Guangdong, China

    Directory of Open Access Journals (Sweden)

    Yuanqi Chen

    2015-03-01

    Full Text Available In order to understand how carbon storage and allocation patterns vary among plantation types, we estimated carbon allocation between above- and below-ground compartments in four subtropical plantations and a naturally recovered shrubland (as a control. Results indicated that the carbon storage and allocation pattern varied greatly among forest types and was highly dependent on specific traits of trees and understory vegetation. The fast-growing species, such as Eucalyptus urophylla, accumulated more carbon in plant biomass. The biomass carbon was about 1.9- and 2.2-times greater than the 10-species mixed plantation and Castanopsis hystrix plantations, respectively. Meanwhile, the plantations sequestered 1.5- to 3-times more carbon in biomass than naturally recovered shrubland. The carbon allocation pattern between above- and below-ground compartments also varied with plantation type and stand age. The ratio of tree root carbon to tree aboveground carbon decreased with stand age for Eucalyptus urophylla and the 10-species mixed plantation. In contrast, the ratio increased for Acacia crassicarpa. Our data suggested that planting the fast-growing species in the degraded land of subtropical China was an effective choice in terms of carbon sequestration. The information about carbon allocation patterns was also valuable for decision making in sustainable forest management and climate change mitigation.

  6. Incorporating climate into belowground carbon estimates in the national greenhouse gas inventory

    Science.gov (United States)

    Matthew B. Russell; Grant M. Domke; Christopher W. Woodall; Anthony W. D’Amato

    2015-01-01

    Refined estimation of carbon (C) stocks within forest ecosystems is a critical component of efforts to reduce greenhouse gas emissions and mitigate the effects of projected climate change through forest C management. Recent evidence has pointed to the importance of climate as a driver of belowground C stocks. This study describes an approach for adjusting allometric...

  7. Luxury consumption of soil nutrients: a possible competitive strategy in above-ground and below-ground biomass allocation and root morphology for slow-growing arctic vegetation?

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Gough, L.; Hobbie, S.E.; Shaver, G.R.

    2003-01-01

    1 A field-experiment was used to determine how plant species might retain dominance in an arctic ecosystem receiving added nutrients. We both measured and modelled the above-ground and below-ground biomass allocation and root morphology of non-acidic tussock tundra near Toolik Lake, Alaska, after 4

  8. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, Martin; Jansa, Jan

    2017-01-01

    Quantification of carbon (C) fluxes in mycorrhizal plants is one of the important yet little explored tasks of mycorrhizal physiology and ecology. 13 CO 2 pulse-chase labelling experiments are increasingly being used to track the fate of C in these plant-microbial symbioses. Nevertheless, continuous monitoring of both the below- and aboveground CO 2 emissions remains a challenge, although it is necessary to establish the full C budget of mycorrhizal plants. Here, a novel CO 2 collection system is presented which allows assessment of gaseous CO 2 emissions (including isotopic composition of their C) from both belowground and shoot compartments. This system then is used to quantify the allocation of recently fixed C in mycorrhizal versus nonmycorrhizal Medicago truncatula plants with comparable biomass and mineral nutrition. Using this system, we confirmed substantially greater belowground C drain in mycorrhizal versus nonmycorrhizal plants, with the belowground CO 2 emissions showing large variation because of fluctuating environmental conditions in the glasshouse. Based on the assembled 13 C budget, the C allocation to the mycorrhizal fungus was between 2.3% (increased 13 C allocation to mycorrhizal substrate) and 2.9% (reduction of 13 C allocation to mycorrhizal shoots) of the plant gross photosynthetic production. Although the C allocation to shoot respiration (measured during one night only) did not differ between the mycorrhizal and nonmycorrhizal plants under our experimental conditions, it presented a substantial part (∼10%) of the plant C budget, comparable to the amount of CO 2 released belowground. These results advocate quantification of both above- and belowground CO 2 emissions in future studies.

  9. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi

    Czech Academy of Sciences Publication Activity Database

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, M.; Jansa, Jan

    2017-01-01

    Roč. 27, č. 1 (2017), s. 35-51 ISSN 0940-6360 R&D Projects: GA MŠk(CZ) LK11224; GA ČR(CZ) GA14-19191S Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:61388971 Keywords : Belowground carbon (C) allocation * C-13 isotope labelling * Glomeromycota Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.047, year: 2016

  10. Advanced remote sensing to quantify temperate peatland capacity for belowground carbon capture

    Science.gov (United States)

    Byrd, K. B.; Blanchard, S.; Schile, L. M.; Kolding, S.; Kelly, M.; Windham-Myers, L.; Miller, R.

    2011-12-01

    Temperate peatlands typically dominated by grasses and sedges generate among the greatest annual rates of net primary productivity (NPP, up to 4 kg C m-2) and soil carbon storage (up to 1 kg C m-2) for natural ecosystems. Belowground tissues represent 20-80% of total NPP, thus understanding the controls on belowground NPP (BNPP) in these wetland ecosystems is particularly important to quantifying peatland carbon balances. In addition, there is a growing need to quantify large-scale belowground C sequestration rates in wetlands to better understand marsh resilience to sea level rise and to help define eligibility for carbon offset credits. Since plant productivity influences wetland C budgets, combining field and remote sensing techniques for estimating above and belowground productivity of wetland vegetation over a large spatial extent will help to address these needs. We are working in a USGS long-term experimental wetland restoration site on drained peatland in the Sacramento-San Joaquin River Delta. Using the spatial variability in water depth and residence time across the 7 ha wetland, our goal is to develop practical methods to quantify and map BNPP of emergent marsh vegetation from remotely sensed estimates of aboveground plant characteristics and aboveground NPP. Field data collected on wetland plants hardstem bulrush (Schoenoplectus acutus) and cattail (Typha spp.) were coupled with reflectance data from a field spectrometer (range 350-2500 nm) every two to three weeks during the summer of 2011. We are analyzing reflectance data to develop hyperspectral indices that predict the biophysical characteristics of wetland vegetation - biomass, leaf area index (LAI), and the fraction of absorbed photosynthetically active radiation (fAPAR) - which may be used to infer belowground biomass and productivity. Soil cores and root in-growth bags were used to calculate root biomass and productivity rates. Existing allometric relationships were used to calculate

  11. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    Science.gov (United States)

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations. © 2015 John Wiley & Sons Ltd.

  12. Variability in above- and belowground carbon stocks in a Siberian larch watershed

    Directory of Open Access Journals (Sweden)

    E. E. Webb

    2017-09-01

    Full Text Available Permafrost soils store between 1330 and 1580 Pg carbon (C, which is 3 times the amount of C in global vegetation, almost twice the amount of C in the atmosphere, and half of the global soil organic C pool. Despite the massive amount of C in permafrost, estimates of soil C storage in the high-latitude permafrost region are highly uncertain, primarily due to undersampling at all spatial scales; circumpolar soil C estimates lack sufficient continental spatial diversity, regional intensity, and replication at the field-site level. Siberian forests are particularly undersampled, yet the larch forests that dominate this region may store more than twice as much soil C as all other boreal forest types in the continuous permafrost zone combined. Here we present above- and belowground C stocks from 20 sites representing a gradient of stand age and structure in a larch watershed of the Kolyma River, near Chersky, Sakha Republic, Russia. We found that the majority of C stored in the top 1 m of the watershed was stored belowground (92 %, with 19 % in the top 10 cm of soil and 40 % in the top 30 cm. Carbon was more variable in surface soils (10 cm; coefficient of variation (CV  =  0.35 between stands than in the top 30 cm (CV  =  0.14 or soil profile to 1 m (CV  =  0.20. Combined active-layer and deep frozen deposits (surface – 15 m contained 205 kg C m−2 (yedoma, non-ice wedge and 331 kg C m−2 (alas, which, even when accounting for landscape-level ice content, is an order of magnitude more C than that stored in the top meter of soil and 2 orders of magnitude more C than in aboveground biomass. Aboveground biomass was composed of primarily larch (53 % but also included understory vegetation (30 %, woody debris (11 % and snag (6 % biomass. While aboveground biomass contained relatively little (8 % of the C stocks in the watershed, aboveground processes were linked to thaw depth and

  13. Impacts of Jatropha-based biodiesel production on above and below-ground carbon stocks: A case study from Mozambique

    International Nuclear Information System (INIS)

    Vang Rasmussen, Laura; Rasmussen, Kjeld; Bech Bruun, Thilde

    2012-01-01

    The need to mitigate climate change makes production of liquid biofuels a high priority. Substituting fossil fuels by biodiesel produced from Jatropha curcas has gained widespread attention as Jatropha cultivation is claimed to offer green house gas emission reductions. Farmers respond worldwide to this increasing demand by converting forests into Jatropha, but whether Jatropha-based biodiesel offers carbon savings depends on the carbon emissions that occur when land use is changed to Jatropha. This paper provides an impact assessment of a small-scale Jatropha project in Cabo Delgado, Mozambique. The paper outlines the estimated impacts on above and below-ground carbon stocks when land use is changed to increase Jatropha production. The results show that expansion of Jatropha production will most likely lead to the conversion of miombo forest areas to Jatropha, which implies a reduction in above and below-ground carbon stocks. The carbon debts created by the land use change can be repaid by replacing fossil fuels with Jatropha-based biodiesel. A repayment time of almost two centuries is found with optimistic estimates of the carbon debt, while the use of pessimistic values results in a repayment time that approaches the millennium. - Highlights: ► Demands for biofuels make production of Jatropha-based biodiesel a priority. ► Farmers in Northern Mozambique are likely to convert un-logged miombo to Jatropha. ► Converting miombo to Jatropha creates reductions in above and below-ground carbon. ► It takes 187–966 years to repay emissions from above and below-ground carbon stocks.

  14. Effects of Soil Texture on Belowground Carbon and Nutrient Storage in a Lowland Amazonian Forest Ecosystem.

    Science.gov (United States)

    Whendee L. Silver; Jason Neff; Megan McGroddy; Ed Veldkamp; Michael Keller; Raimundo Cosme

    2000-01-01

    Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian...

  15. Evaluation of Net Primary Productivity and Carbon Allocation to Different Parts of Corn in Different Tillage and Nutrient Management Systems

    Directory of Open Access Journals (Sweden)

    esmat mohammadi

    2017-09-01

    Full Text Available Evaluation of net primary productivity and carbon allocation to different organs of corn under nutrient management and tillage systems Introduction Agriculture operations produce 10 to 20 percent of greenhouse gases. As a result of conventional operations of agriculture, greenhouse gases have been increased (Osborne et al., 2010. Therefor it is necessary to notice to carbon sequestration to reduce greenhouse gases emissions. In photosynthesis process, plants absorb CO2 and large amounts of organic carbon accumulate in their organs. Biochar is produced of pyrolysis of organic compounds. Biochar is an appropriate compound for improved of soil properties and carbon sequestration (Whitman and Lehmann, 2009; Smith et al., 2010. Conservation tillage has become an important technology in sustainable agriculture due to its benefits. So the aim of this study was to evaluate the effect of nutrient management and tillage systems on net primary production and carbon allocation to different organs of corn in Shahrood. Material and methods This study was conducted at the Shahrood University of Technology research farm. Experiment was done as split plot in randomized complete block design with three replications. Tillage systems with two levels (conventional tillage and minimum tillage were as the main factor and nutrient management in seven levels including (control, chemical fertilizer, manure, biochar, chemical fertilizer + manure, chemical fertilizer + biochar, manure + biochar were considered as sub plot. At the time of maturity of corn, was sampled from its aboveground and belowground biomasses. Carbon content of shoot, seed and root was considered almost 45 percent of yield of each of these biomasses and carbon in root exudates almost 65 percent of carbon in the root. Statistical analysis of the data was performed using SAS program. Comparison of means was conducted with LSD test at the 5% level. Results and discussion Effect of nutrient management was

  16. Assessing the Impact of Model Parameter Uncertainty in Simulating Grass Biomass Using a Hybrid Carbon Allocation Strategy

    Science.gov (United States)

    Reyes, J. J.; Adam, J. C.; Tague, C.

    2016-12-01

    Grasslands play an important role in agricultural production as forage for livestock; they also provide a diverse set of ecosystem services including soil carbon (C) storage. The partitioning of C between above and belowground plant compartments (i.e. allocation) is influenced by both plant characteristics and environmental conditions. The objectives of this study are to 1) develop and evaluate a hybrid C allocation strategy suitable for grasslands, and 2) apply this strategy to examine the importance of various parameters related to biogeochemical cycling, photosynthesis, allocation, and soil water drainage on above and belowground biomass. We include allocation as an important process in quantifying the model parameter uncertainty, which identifies the most influential parameters and what processes may require further refinement. For this, we use the Regional Hydro-ecologic Simulation System, a mechanistic model that simulates coupled water and biogeochemical processes. A Latin hypercube sampling scheme was used to develop parameter sets for calibration and evaluation of allocation strategies, as well as parameter uncertainty analysis. We developed the hybrid allocation strategy to integrate both growth-based and resource-limited allocation mechanisms. When evaluating the new strategy simultaneously for above and belowground biomass, it produced a larger number of less biased parameter sets: 16% more compared to resource-limited and 9% more compared to growth-based. This also demonstrates its flexible application across diverse plant types and environmental conditions. We found that higher parameter importance corresponded to sub- or supra-optimal resource availability (i.e. water, nutrients) and temperature ranges (i.e. too hot or cold). For example, photosynthesis-related parameters were more important at sites warmer than the theoretical optimal growth temperature. Therefore, larger values of parameter importance indicate greater relative sensitivity in

  17. SPATIAL AND VERTICAL DISTRIBUTION OF LITTER AND BELOWGROUND CARBON IN A BRAZILIAN CERRADO VEGETATION

    Directory of Open Access Journals (Sweden)

    Vinícius Augusto Morais

    2017-03-01

    Full Text Available Forest ecosystems contribute significantly to store greenhouse gases. This paper aimed to investigate the spatial and vertical distribution of litter, roots, and soil carbon. We obtained biomass and carbon of compartments (litter, roots, and soil in a vegetation from Cerrado biome, state of Minas Gerais, Brazil. The materials were collected in 7 0.5 m² sub-plots randomly allocated in the vegetation. Root and soil samples were taken from five soil layers across the 0-100 cm depth. Roots were classified into three diameter classes: fine (10 mm roots. The carbon stock was mapped through geostatistical analysis. The results indicated averages of soil carbon stock of 208.5 Mg.ha-1 (94.6% of the total carbon, root carbon of 6.8 Mg.ha-1 (3.1%, and litter of 5 Mg.ha-1 (2.3%. The root carbon was majority stored in coarse roots (83%, followed by fine (10%, and medium roots (7%. The largest portion of fine roots concentrated in the 0-10 cm soil depth, whereas medium and coarse roots were majority in the 10-20 cm depth. The largest portion of soil (53% and root (85% carbon were stored in superficial soil layers (above 40 cm. As conclusion, the carbon spatial distribution follows a reasonable trend among the compartments. There is a vertical relation of which the deeper the soil layer, the lower the soil and root carbon stock. Excepting the shallowest layer, coarse roots held the largest portion of carbon across the evaluated soil layers.

  18. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Energy Technology Data Exchange (ETDEWEB)

    Cusack, D.; Silver, W.L.; Torn, M.S.; McDowell, W.H.

    2011-04-15

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and upper elevation tropical rain forests in Puerto Rico to explore the responses of above- and belowground C pools to N addition. As expected, tree stem growth and litterfall productivity did not respond to N fertilization in either of these Nrich forests, indicating a lack of N limitation to net primary productivity (NPP). In contrast, soil C concentrations increased significantly with N fertilization in both forests, leading to larger C stocks in fertilized plots. However, different soil C pools responded to N fertilization differently. Labile (low density) soil C fractions and live fine roots declined with fertilization, while mineral-associated soil C increased in both forests. Decreased soil CO2 fluxes in fertilized plots were correlated with smaller labile soil C pools in the lower elevation forest (R2 = 0.65, p\\0.05), and with lower live fine root biomass in the upper elevation forest (R2 = 0.90, p\\0.05). Our results indicate that soil C storage is sensitive to N deposition in tropical forests, even where plant productivity is not N-limited. The mineral-associated soil C pool has the potential to respond relatively quickly to N additions, and can drive increases in bulk soil C stocks in tropical forests.

  19. Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar.

    Science.gov (United States)

    Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V; Kolka, Randall

    2015-01-01

    A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C.

  20. Impacts of afforestation and silviculture on the soil C balance of tropical tree plantations: belowground C allocation, soil CO2 efflux and C accretion (Invited)

    Science.gov (United States)

    Epron, D.; Koutika, L.; Mareschal, L.; Nouvellon, Y.

    2013-12-01

    Tropical forest plantations will provide a large part of the global wood supply which is anticipated to increase sharply in the next decades, becoming a valuable source of income in many countries, where they also contribute to land use changes that impact the global carbon (C) cycle. Tropical forest plantations established on previous grasslands are potential C sinks offsetting anthropogenic CO2 emissions. When they are managed on short rotations, the aboveground biomass is frequently removed and transformed into wood products with short lifetimes. The soil is thus the only compartment for durable C sequestration. The soil C budget results from the inputs of C from litterfall, root turnover and residues left at logging stage, balanced by C losses through heterotrophic respiration and leaching of organic C with water flow. Intensive researches have been conducted these last ten years in eucalypt plantations in the Congo on the effects of management options on soil fertility improvement and C sequestration. Our aim is to review important results regarding belowground C allocation, soil CO2 efflux and C accretion in relation to management options. We will specifically address (i) the soil C dynamics after afforestation of a tropical savannah, (ii) the impact of post-harvest residue management, and (iii) the beneficial effect of introducing nitrogen fixing species for C sequestration. Our results on afforestation of previous savannah showed that mechanical soil disturbance for site preparation had no effect on soil CO2 efflux and soil C balance. Soil C increased after afforestation despite a rapid disappearance of the labile savannah-derived C because a large fraction of savannah-derived C is stable and the aboveground litter layer is as the major source of CO2 contributing to soil CO2 efflux. We further demonstrated that the C stock in and on the soil slightly increased after each rotation when large amounts of residues are left at logging stage and that most of

  1. Alteration of belowground carbon dynamics by nitrogen addition in southern California mixed conifer forests

    Science.gov (United States)

    N.S. Nowinski; S.E. Trumbore; G. Jimenez; M.E. Fenn

    2009-01-01

    Nitrogen deposition rates in southern California are the highest in North America and have had substantial effects on ecosystem functioning. We document changes in the belowground C cycle near ponderosa pine trees experiencing experimental nitrogen (N) addition (50 and 150 kg N ha−1 a−1 as slow release urea since 1997) at two end‐member...

  2. Carbon allocation and carbon isotope fluxes in the plant-soil-atmosphere continuum: a review

    Directory of Open Access Journals (Sweden)

    N. Brüggemann

    2011-11-01

    Full Text Available The terrestrial carbon (C cycle has received increasing interest over the past few decades, however, there is still a lack of understanding of the fate of newly assimilated C allocated within plants and to the soil, stored within ecosystems and lost to the atmosphere. Stable carbon isotope studies can give novel insights into these issues. In this review we provide an overview of an emerging picture of plant-soil-atmosphere C fluxes, as based on C isotope studies, and identify processes determining related C isotope signatures. The first part of the review focuses on isotopic fractionation processes within plants during and after photosynthesis. The second major part elaborates on plant-internal and plant-rhizosphere C allocation patterns at different time scales (diel, seasonal, interannual, including the speed of C transfer and time lags in the coupling of assimilation and respiration, as well as the magnitude and controls of plant-soil C allocation and respiratory fluxes. Plant responses to changing environmental conditions, the functional relationship between the physiological and phenological status of plants and C transfer, and interactions between C, water and nutrient dynamics are discussed. The role of the C counterflow from the rhizosphere to the aboveground parts of the plants, e.g. via CO2 dissolved in the xylem water or as xylem-transported sugars, is highlighted. The third part is centered around belowground C turnover, focusing especially on above- and belowground litter inputs, soil organic matter formation and turnover, production and loss of dissolved organic C, soil respiration and CO2 fixation by soil microbes. Furthermore, plant controls on microbial communities and activity via exudates and litter production as well as microbial community effects on C mineralization are reviewed. A further part of the paper is dedicated to physical interactions between soil CO2 and the soil matrix, such as

  3. Similar below-ground carbon cycling dynamics but contrasting modes of nitrogen cycling between arbuscular mycorrhizal and ectomycorrhizal forests.

    Science.gov (United States)

    Lin, Guigang; McCormack, M Luke; Ma, Chengen; Guo, Dali

    2017-02-01

    Compared with ectomycorrhizal (ECM) forests, arbuscular mycorrhizal (AM) forests are hypothesized to have higher carbon (C) cycling rates and a more open nitrogen (N) cycle. To test this hypothesis, we synthesized 645 observations, including 22 variables related to below-ground C and N dynamics from 100 sites, where AM and ECM forests co-occurred at the same site. Leaf litter quality was lower in ECM than in AM trees, leading to greater forest floor C stocks in ECM forests. By contrast, AM forests had significantly higher mineral soil C concentrations, and this result was strongly mediated by plant traits and climate. No significant differences were found between AM and ECM forests in C fluxes and labile C concentrations. Furthermore, inorganic N concentrations, net N mineralization and nitrification rates were all higher in AM than in ECM forests, indicating 'mineral' N economy in AM but 'organic' N economy in ECM trees. AM and ECM forests show systematic differences in mineral vs organic N cycling, and thus mycorrhizal type may be useful in predicting how different tree species respond to multiple environmental change factors. By contrast, mycorrhizal type alone cannot reliably predict below-ground C dynamics without considering plant traits and climate. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  4. Belowground Plant Dynamics Across an Arctic Landscape

    Science.gov (United States)

    Salmon, V. G.; Iversen, C. M.; Breen, A. L.; Thornton, P. E.; Wullschleger, S.

    2017-12-01

    High-latitude ecosystems are made up of a mosaic of different plant communities, all of which are exposed to warming at a rate double that observed in ecosystems at lower latitudes. Arctic regions are an important component of global Earth system models due to the large amounts of soil carbon (C) currently stored in permafrost as well their potential for increased plant C sequestration under warmer conditions. Losses of C from thawing and decomposing permafrost may be offset by increased plant productivity, but plant allocation to belowground structures and acquisition of limiting nutrients remain key sources of uncertainty in these ecosystems. The relationship between belowground plant traits and environmental conditions is not well understood, nor are tradeoffs between above- and belowground plant traits. To address these knowledge gaps, we sampled above- and belowground plant tissues along the Kougarok Hillslope on the Seward Peninsula, Alaska. The vegetation communities sampled included Alder shrubland, willow birch tundra, tussock tundra, dwarf shrub lichen tundra, and non-acidic mountain complex. Within each plant community, aboveground biomass was quantified and specific leaf area, leaf chemistry (%C, %N, %P and δ15N), and wood density were measured. Belowground fine-root biomass and rooting depth distribution were also determined at the community level. Fine roots from shrubs and graminoids were separated so that specific root area, diameter, and chemistry (%C, %N, %P and δ15N) could be assessed for these contrasting plant functional types. Initial findings indicate fine root biomass pools across the widely varying plant communities are constrained by soil depth, regardless of whether the rooting zone is restricted by permafrost or rock. The presence of Alnus viridis subspp. fruticosa, a deciduous shrub that facilitates nitrogen (N) fixation within its root nodules by Frankia bacteria, in Alder shrubland and willow birch tundra communities was associated

  5. Effect of long-term drought on carbon allocation and nitrogen uptake of Pinus sylvestris seedlings

    Science.gov (United States)

    Pumpanen, Jukka; Aaltonen, Heidi; Lindén, Aki; Köster, Kajar; Biasi, Christina; Heinonsalo, Jussi

    2015-04-01

    Weather extremes such as drought events are expected to increase in the future as a result of climate change. The drought affects the allocation of carbon assimilated by plants e.g. by modifying the root to shoot ratio, amount of fine roots and the amount of mycorrhizal fungal hyphae. We studied the effect of long term drought on the allocation of carbon in a common garden experiment with 4-year-old Pinus sylvestris seedlings. Half of the seedlings were exposed to long-term drought by setting the soil water content close to wilting point for over two growing seasons whereas the other half was grown in soil close to field capacity. We conducted a pulse labelling with 13CO2 in the end of the study by injecting a known amount of 13C enriched CO2 to the seedlings and measuring the CO2 uptake and distribution of 13C to the biomass of the seedlings and to the root and rhizosphere respiration. In addition, we studied the effect of drought on the decomposition of needle litter and uptake of nitrogen by 15N labelled needles buried in the soil in litter bags. The litterbags were collected and harvested in the end of the experiment and the changes in microbial community in the litterbags were studied from the phospholipid fatty acid (PLFA) composition. We also determined the 15N isotope concentrations from the needles of the seedlings to study the effect of drought on the nitrogen uptake of the seedlings. Our results indicate that the drought had a significant effect both on the biomass allocation of the seedlings and on the microbial species composition. The amount of carbon allocated belowground was much higher in the seedlings exposed to drought compared to the control seedlings. The seedlings seemed to adapt their carbon allocation to long-term drought to sustain adequate needle biomass and water uptake. The seedlings also adapted their osmotic potential and photosynthesis capacity to sustain the long-term drought as was indicated by the measurements of osmotic potential

  6. Contrasting above- and belowground organic matter decomposition and carbon and nitrogen dynamics in response to warming in High Arctic tundra.

    Science.gov (United States)

    Blok, Daan; Faucherre, Samuel; Banyasz, Imre; Rinnan, Riikka; Michelsen, Anders; Elberling, Bo

    2017-12-13

    Tundra regions are projected to warm rapidly during the coming decades. The tundra biome holds the largest terrestrial carbon pool, largely contained in frozen permafrost soils. With warming, these permafrost soils may thaw and become available for microbial decomposition, potentially providing a positive feedback to global warming. Warming may directly stimulate microbial metabolism but may also indirectly stimulate organic matter turnover through increased plant productivity by soil priming from root exudates and accelerated litter turnover rates. Here, we assess the impacts of experimental warming on turnover rates of leaf litter, active layer soil and thawed permafrost sediment in two high-arctic tundra heath sites in NE-Greenland, either dominated by evergreen or deciduous shrubs. We incubated shrub leaf litter on the surface of control and warmed plots for 1 and 2 years. Active layer soil was collected from the plots to assess the effects of 8 years of field warming on soil carbon stocks. Finally, we incubated open cores filled with newly thawed permafrost soil for 2 years in the active layer of the same plots. After field incubation, we measured basal respiration rates of recovered thawed permafrost cores in the lab. Warming significantly reduced litter mass loss by 26% after 1 year incubation, but differences in litter mass loss among treatments disappeared after 2 years incubation. Warming also reduced litter nitrogen mineralization and decreased the litter carbon to nitrogen ratio. Active layer soil carbon stocks were reduced 15% by warming, while soil dissolved nitrogen was reduced by half in warmed plots. Warming had a positive legacy effect on carbon turnover rates in thawed permafrost cores, with 10% higher respiration rates measured in cores from warmed plots. These results demonstrate that warming may have contrasting effects on above- and belowground tundra carbon turnover, possibly governed by microbial resource availability. © 2017 John

  7. Directed graph based carbon flow tracing for demand side carbon obligation allocation

    DEFF Research Database (Denmark)

    Sun, Tao; Feng, Donghan; Ding, Teng

    2016-01-01

    In order to achieve carbon emission abatement, some researchers and policy makers have cast their focus on demand side carbon abatement potentials. This paper addresses the problem of carbon flow calculation in power systems and carbon obligation allocation at demand side. A directed graph based...... method for tracing carbon flow is proposed. In a lossy network, matrices such as carbon losses, net carbon intensity (NCI) and footprint carbon intensity (FCI) are obtained with the proposed method and used to allocate carbon obligation at demand side. Case studies based on realistic distribution...... and transmission systems are provided to demonstrate the effectiveness of the proposed method....

  8. 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

  9. Climate change affects carbon allocation to the soil in shrublands

    DEFF Research Database (Denmark)

    Gorissen, A.; Tietema, A.; Joosten, N.N.

    2004-01-01

    , resulting from imposed manipulations, on carbon dynamics in shrubland ecosystems was examined. We performed a C-14-labeling experiment to probe changes in net carbon uptake and allocation to the roots and soil compartments as affected by a higher temperature during, the year and a drought period...... than or equal to 0.10. Drought clearly reduced carbon flow from the roots to the soil compartments. The fraction of the C-14 fixed by the plants and allocated into the soluble carbon fraction in the soil and to soil microbial biomass in Denmark and the UK decreased by more than 60%. The effects......Climate change may affect ecosystem functioning through increased temperatures or changes in precipitation patterns. Temperature and water availability are important drivers for ecosystem processes such as photosynthesis, carbon translocation, and organic matter decomposition. These climate changes...

  10. Towards an understanding of the molecular regulation of carbon allocation in diatoms: the interaction of energy and carbon allocation.

    Science.gov (United States)

    Wagner, Heiko; Jakob, Torsten; Fanesi, Andrea; Wilhelm, Christian

    2017-09-05

    In microalgae, the photosynthesis-driven CO 2 assimilation delivers cell building blocks that are used in different biosynthetic pathways. Little is known about how the cell regulates the subsequent carbon allocation to, for example, cell growth or for storage. However, knowledge about these regulatory mechanisms is of high biotechnological and ecological importance. In diatoms, the situation becomes even more complex because, as a consequence of their secondary endosymbiotic origin, the compartmentation of the pathways for the primary metabolic routes is different from green algae. Therefore, the mechanisms to manipulate the carbon allocation pattern cannot be adopted from the green lineage. This review describes the general pathways of cellular energy distribution from light absorption towards the final allocation of carbon into macromolecules and summarizes the current knowledge of diatom-specific allocation patterns. We further describe the (limited) knowledge of regulatory mechanisms of carbon partitioning between lipids, carbohydrates and proteins in diatoms. We present solutions to overcome the problems that hinder the identification of regulatory elements of carbon metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Author(s).

  11. Winter wheat optimizes allocation in response to carbon limitation

    Science.gov (United States)

    Huang, Jianbei; Hammerbacher, Almuth; Trumbore, Susan; Hartmann, Henrik

    2016-04-01

    • Plant photosynthesis is not carbon-saturated at current atmospheric CO2 concentration ([CO2]) thus carbon allocation priority is of critical importance in determining plant response to environmental changes, including increasing [CO2]. • We quantified the percentage of daytime net assimilation (A) allocated to whole-plant nighttime respiration (R) and structural growth (SG), nonstructural carbohydrates (NSC) and secondary metabolites (SMs) during winter wheat (Triticum aestivum) vegetative growth (over 4 weeks) at glacial, ambient, and elevated [CO2] (170, 390 and 680 ppm). • We found that R/A remained relatively constant (11-14%) across [CO2] treatments, whereas plants allocated less C to growth and more C to export at low [CO2] than elevated [CO2]; low [CO2] grown plants tended to invest overall less C into NSC and SMs than to SG due to reduced NSC availability; while leaf SMs/NSC was greater at 170 ppm than at 680 ppm [CO2] this was the opposite for root SMs/NSC; biomass, especially NSC, were preferentially allocated to leaves instead of stems and roots, likely to relieve C limitation induced by low [CO2]. • We conclude that C limitation may force plants to reduce C allocation to long-term survival in order to secure short-term survival. Furthermore, they optimized allocation of the available resource by concentrating biomass and storage to those tissues responsible for assimilation.

  12. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Science.gov (United States)

    Daniela F. Cusack; Whendee L. Silver; Margaret S. Torn; William H. McDowell

    2011-01-01

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and...

  13. How does warming affect carbon allocation, respiration and residence time in trees? An isotope tracer approach in a eucalypt

    Science.gov (United States)

    Pendall, E.; Drake, J. E.; Furze, M.; Barton, C. V.; Carillo, Y.; Richter, A.; Tjoelker, M. G.

    2017-12-01

    Climate warming has the potential to alter the balance between photosynthetic carbon assimilation and respiratory losses in forest trees, leading to uncertainty in predicting their future physiological functioning. In a previous experiment, warming decreased canopy CO2 assimilation (A) rates of Eucalyptus tereticornis trees, but respiration (R) rates were usually not significantly affected, due to physiological acclimation to temperature. This led to a slight increase in (R/A) and thus decrease in plant carbon use efficiency with climate warming. In contrast to carbon fluxes, the effect of warming on carbon allocation and residence time in trees has received less attention. We conducted a study to test the hypothesis that warming would decrease the allocation of C belowground owing to reduced cost of nutrient uptake. E. parramattensis trees were grown in the field in unique whole-tree chambers operated at ambient and ambient +3 °C temperature treatments (n=3 per treatment). We applied a 13CO2 pulse and followed the label in CO2 respired from leaves, roots, canopy and soil, in plant sugars, and in rhizosphere microbes over a 3-week period in conjunction with measurements of tree growth. The 9-m tall, 57 m3 whole-tree chambers were monitored for CO2 concentrations in independent canopy and below ground (root and soil) compartments; periodic monitoring of δ13C values in air in the compartments allowed us to quantify the amount of 13CO2 assimilated and respired by each tree. Warmed trees grew faster and assimilated more of the label than control trees, but the 13C allocation to canopy, root and soil respiration was not altered. However, warming appeared to reduce the residence time of carbon respired from leaves, and especially from roots and soil, indicating that autotrophic respiration has the potential to feedback to climate change. This experiment provides insights into how warming may affect the fate of assimilated carbon from the leaf to the ecosystem scale.

  14. Genomics Mechanisms of Carbon Allocation and Partitioning in Poplar

    Energy Technology Data Exchange (ETDEWEB)

    Kirst, Matias; Peter, Gary; Martin, Timothy

    2009-07-30

    The genetic control of carbon allocation and partitioning in woody perennial plants is poorly understood despite its importance for carbon sequestration. It is also unclear how environmental cues such as nitrogen availability impact the genes that regulate growth, and biomass allocation and wood composition in trees. To address these questions we phenotyped 396 clonally replicated genotypes of an interspecific pseudo-backcross pedigree of Populus for wood composition and biomass traits in above and below ground organs. The loci that regulate growth, carbon allocation and partitioning under two nitrogen conditions were identified, defining the contribution of environmental cues to their genetic control. Fifty-seven quantitative trait loci (QTL) were identified for twenty traits analyzed. The majority of QTL are specific to one of the two nitrogen treatments, demonstrating significant nitrogen-dependent genetic control. A highly significant genetic correlation was observed between plant growth and lignin/cellulose composition, and QTL co-localization identified the genomic position of potential pleiotropic regulators. Gene expression analysis of all poplar genes was also characterized in differentiating xylem, whole-roots and developing leaves of 192 of the segregating population. By integrating the QTL and gene expression information we identified genes that regulate carbon partitioning and several biomass growth related properties. The work developed in this project resulted in the publication of three book chapters, four scientific articles (three others currently in preparation), 17 presentations in international conferences and two provisional patent applications.

  15. Total belowground carbon flux in subalpine forests is related to leaf area index, soil nitrogen, and tree height

    Science.gov (United States)

    Berryman, Erin Michele; Ryan, Michael G.; Bradford, John B.; Hawbaker, Todd J.; Birdsey, R.

    2016-01-01

    In forests, total belowground carbon (C) flux (TBCF) is a large component of the C budget and represents a critical pathway for delivery of plant C to soil. Reducing uncertainty around regional estimates of forest C cycling may be aided by incorporating knowledge of controls over soil respiration and TBCF. Photosynthesis, and presumably TBCF, declines with advancing tree size and age, and photosynthesis increases yet C partitioning to TBCF decreases in response to high soil fertility. We hypothesized that these causal relationships would result in predictable patterns of TBCF, and partitioning of C to TBCF, with natural variability in leaf area index (LAI), soil nitrogen (N), and tree height in subalpine forests in the Rocky Mountains, USA. Using three consecutive years of soil respiration data collected from 22 0.38-ha locations across three 1-km2 subalpine forested landscapes, we tested three hypotheses: (1) annual soil respiration and TBCF will show a hump-shaped relationship with LAI; (2) variability in TBCF unexplained by LAI will be related to soil nitrogen (N); and (3) partitioning of C to TBCF (relative to woody growth) will decline with increasing soil N and tree height. We found partial support for Hypothesis 1 and full support for Hypotheses 2 and 3. TBCF, but not soil respiration, was explained by LAI and soil N patterns (r2 = 0.49), and the ratio of annual TBCF to TBCF plus aboveground net primary productivity (ANPP) was related to soil N and tree height (r2 = 0.72). Thus, forest C partitioning to TBCF can vary even within the same forest type and region, and approaches that assume a constant fraction of TBCF relative to ANPP may be missing some of this variability. These relationships can aid with estimates of forest soil respiration and TBCF across landscapes, using spatially explicit forest data such as national inventories or remotely sensed data products.

  16. As above, so below? How the interplay between overstory species and edaphic factors influences the magnitude and mechanisms of belowground carbon cycles.

    Science.gov (United States)

    Desie, Ellen; Vancampenhout, Karen; Buelens, Jeroen; Verstraeten, Gorik; Verheyen, Kris; Heyens, Kathleen; Muys, Bart

    2017-04-01

    The choice of overstory species in relation to soil properties is one of the most important management decisions in forestry, especially when deciduous or mixed stands are replaced by coniferous monocultures. When assessed in relation to climate change, conversion effects are mainly studied in terms of total carbon stocks. These are generally considered to evolve linearly, according to similar stabilization processes across ecosystems. Here we show that the belowground carbon cycle is subject to ecosystem-specific stable process domains. The process domains are separated by steep thresholds, or even tipping points, where a small increase in environmental forcing can cause a drastic change in the way the ecosystem processes carbon. These effects are demonstrated in detail for the old-growth forest complex of the Gaume in Belgium. This forest spans a lithological gradient and mixed-species stands occur next to stands recently converted to Norway spruce (Picea abies) monocultures, creating a setting of paired plots that allow to address the magnitude of management choices relative to intrinsic natural potential. Vegetation descriptions, litter samples and soil samples at different depths were compared for above- and belowground functional biodiversity, litter layer characteristics, soil properties, nutrient status, bioturbation, soil carbon stocks and soil carbon functional pools. Results show that in soils with limited remaining buffer capacity, overstory-induced acidification under spruce causes a shift to an acid aluminum buffered environment, with a collapse in variability of abiotic and biotic soil properties. This entails a shift in soil fauna and depth relations, with a clear decoupling of the litter layer from the topsoil and the subsoil in terms of biological communities, carbon input and stochastic constraints. Finally, this study indicates that although spruce conversion increases the total soil carbon stocks, this extra carbon is stored in more labile

  17. Ecophysiological differences in tree carbon gain and water use for two fast growing loblolly pine ideotypes that differ in carbon allocation

    Science.gov (United States)

    Maier, C. A.; Johnsen, K. H.; Dougherty, P.; Albaugh, T.; Patterson, S.

    2013-12-01

    We examined the ecophysiological basis for differences in growth efficiency and water-use for two contrasting Pinus taeda (L.) ideotypes: a ';broad-crown' (BC) and a ';narrow crown' (NC) clone, which allocate more growth to leaves and wood, respectively. Tree growth, above and belowground biomass production, fine root turnover, light use efficiency (LUE), and transpiration on a ground (Et) and leaf (EL) basis were measured periodically over eight years. Silviculture treatments were a control consisting of shearing and bedding following local commercial operations and a mulch treatment where chipped logging residue (C/N≈700) was incorporated into the soil during bedding at a rate of 25 Mg ha-1. We hypothesized that: 1) the NC and BC clone would display similar aboveground productivity in the control treatment, but because of lower leaf area and thus lower nitrogen demand, the NC would display higher productivity than BC on the mulch treatment, 2) the NC would have higher LUE, and 3) the NC clone would have lower Et and EL. There were no treatment, clone, or interaction effects on stemwood production. At age eight, standing stem biomass was 80.7 and 86.0 Mg ha-1 (p=0.33), for the NC and BC, respectively. However, there were significant clone effects on carbon allocation. The BC had greater foliage (BC: 8.1, NC: 6.6 Mg ha-1, se=0.2, p=0.01) and branch (BC: 15.0, NC: 12.4 Mg ha-1, se=0.4, p2mm) (BC: 9.7, NC: 11.23 Mg ha-1, se=0.2, Parea to conducting sapwood area (AL/AS) (BC: 0.175 m2 cm-2, NC: 0.150 m2 cm-2) than the NC clone. Growth efficiency, defined as annual stem increment per unit leaf area was 5.36 and 4.70 Mg ha-1 yr-1 LAI-1 in the NC and BC, respectively (parea, which confers greater nutrient use efficiency. In addition, the NC had significantly greater belowground carbon allocation, which could have long-term implications for soil carbon sequestration.

  18. Adressing optimality principles in DGVMs: Dynamics of Carbon allocation changes

    Science.gov (United States)

    Pietsch, Stephan

    2017-04-01

    DGVMs are designed to reproduce and quantify ecosystem processes. Based on plant functions or species specific parameter sets, the energy, carbon, nitrogen and water cycles of different ecosystems are assessed. These models have been proven to be important tools to investigate ecosystem fluxes as they are derived by plant, site and environmental factors. The general model approach assumes steady state conditions and constant model parameters. Both assumptions, however, are wrong, since: (i) No given ecosystem ever is at steady state! (ii) Ecosystems have the capability to adapt to changes in growth conditions, e.g. via changes in allocation patterns! This presentation will give examples how these general failures within current DGVMs may be addressed.

  19. The decadal state of the terrestrial carbon cycle : Global retrievals of terrestrial carbon allocation, pools, and residence times

    NARCIS (Netherlands)

    Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  20. BELOWGROUND CARBON ALLOCATION IN FORESTS ESTIMATED FROM LITTERFALL AND IRGA-BASED SOIL RESPIRATION MEASUREMENTS. (R828309)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  1. Regional allocation of carbon emission quotas in China: Evidence from the Shapley value method

    International Nuclear Information System (INIS)

    Zhang, Yue-Jun; Wang, Ao-Dong; Da, Ya-Bin

    2014-01-01

    It is an important task for China to allocate carbon emission quotas among regions so as to realize its carbon reduction targets and establish the national cap-and-trade carbon market. Meanwhile, it is supposed to be cost-effective to jointly reduce China's carbon emissions through some collaborative activities among regions. Then a natural question is how to allocate the quotas among regions in light of the collaboration. For this purpose, the Shapley value method is adopted and the results show that, first, the regions with higher GDP, higher carbon outflow and higher carbon reduction connection should be allocated more carbon quotas. Moreover, when the collaboration is considered, the optimal allocation of carbon quotas among regions will change significantly compared to the basic quotas by the entropy method; and the Central region is allocated the largest proportion of carbon quota among regions, which indicates its largest radiation effect. Besides, the collaboration between the Central region and Northern coast region, and that between the Central region and the Eastern region should be paid close attention. These results may provide insightful support for decision makers to promote collaborative carbon reduction and allocate carbon quotas in China. - Highlights: • The paper allocates carbon quotas given the collaboration among regions in China. • The Shapley value method coupled with the entropy and gravity models is adopted. • The regions with higher GDP, carbon outflow and reduction connection allocate more. • The Central region has the largest radiation effect on others among all regions. • The collaboration of the Central and Northern coast regions should have priority

  2. Coupling carbon allocation with leaf and root phenology predicts tree-grass partitioning along a savanna rainfall gradient

    Science.gov (United States)

    Haverd, V.; Smith, B.; Raupach, M.; Briggs, P.; Nieradzik, L.; Beringer, J.; Hutley, L.; Trudinger, C. M.; Cleverly, J.

    2016-02-01

    The relative complexity of the mechanisms underlying savanna ecosystem dynamics, in comparison to other biomes such as temperate and tropical forests, challenges the representation of such dynamics in ecosystem and Earth system models. A realistic representation of processes governing carbon allocation and phenology for the two defining elements of savanna vegetation (namely trees and grasses) may be a key to understanding variations in tree-grass partitioning in time and space across the savanna biome worldwide. Here we present a new approach for modelling coupled phenology and carbon allocation, applied to competing tree and grass plant functional types. The approach accounts for a temporal shift between assimilation and growth, mediated by a labile carbohydrate store. This is combined with a method to maximize long-term net primary production (NPP) by optimally partitioning plant growth between fine roots and (leaves + stem). The computational efficiency of the analytic method used here allows it to be uniquely and readily applied at regional scale, as required, for example, within the framework of a global biogeochemical model.We demonstrate the approach by encoding it in a new simple carbon-water cycle model that we call HAVANA (Hydrology and Vegetation-dynamics Algorithm for Northern Australia), coupled to the existing POP (Population Orders Physiology) model for tree demography and disturbance-mediated heterogeneity. HAVANA-POP is calibrated using monthly remotely sensed fraction of absorbed photosynthetically active radiation (fPAR) and eddy-covariance-based estimates of carbon and water fluxes at five tower sites along the North Australian Tropical Transect (NATT), which is characterized by large gradients in rainfall and wildfire disturbance. The calibrated model replicates observed gradients of fPAR, tree leaf area index, basal area, and foliage projective cover along the NATT. The model behaviour emerges from complex feedbacks between the plant

  3. Forecasting the Allocation Ratio of Carbon Emission Allowance Currency for 2020 and 2030 in China

    Directory of Open Access Journals (Sweden)

    Shihong Zeng

    2016-07-01

    Full Text Available Many countries and scholars have used various strategies to improve and optimize the allocation ratios for carbon emission allowances. This issue is more urgent for China due to the uneven development across the country. This paper proposes a new method that divides low-carbon economy development processes into two separate periods: from 2020 to 2029 and from 2030 to 2050. These two periods have unique requirements and emissions reduction potential; therefore, they must involve different allocation methods, so that reduction behaviors do not stall the development of regional low-carbon economies. During the first period, a more deterministic economic development approach for the carbon emission allowance allocation ratio should be used. During the second period, more adaptive and optimized policy guidance should be employed. We developed a low-carbon economy index evaluation system using the entropy weight method to measure information filtering levels. We conducted vector autoregressive correlation tests, consulted 60 experts for the fuzzy analytic hierarchy process, and we conducted max-min standardized data processing tests. This article presents first- and second-period carbon emission allowance models in combination with a low-carbon economy index evaluation system. Finally, we forecast reasonable carbon emission allowance allocation ratios for China for the periods starting in 2020 and 2030. A good allocation ratio for the carbon emission allowance can help boost China’s economic development and help the country reach its energy conservation and emissions reduction goals.

  4. Closing the Knowledge Gap: Effects of Land Use Conversion on Belowground Carbon near the 100th Meridian

    Science.gov (United States)

    Waldron, S. E.; Phillips, R. L.; Dell, R.; Suddick, E. C.

    2012-12-01

    Native prairie of the northern Great Plains near the 100th meridian is currently under land use conversion pressure due to high commodity prices. From 2002 to 2007, approximately 303,515 hectares of prairie were converted to crop production in the Prairie Pothole Region (PPR) from Montana to the Dakotas. The spatiotemporal effects of land-use conversion on soil organic matter are still unclear for the PPR. Effects will vary with management, soil properties and time, making regional experiments and simulation modeling necessary. Grassland conservationists are interested in soil carbon data and soil carbon simulation models to inform potential voluntary carbon credit programs. These programs require quantification of changes in soil carbon associated with land-use conversion and management. We addressed this issue by 1) designing a regional-scale experiment, 2) collecting and analyzing soil data, and 3) interviewing producers about land management practices, as required for regional, process-based biogeochemical models. We selected farms at random within a 29,000 km2 area of interest and measured soil properties at multiple depths for native prairie and adjacent annual crop fields. The cores were processed at six different depths (between 0 and 100 cm) for bulk density, pH, texture, total carbon, inorganic carbon, and total nitrogen. We found that the largest difference in soil organic carbon occurred at the 0-10 cm depth, but the magnitude of the effect of land use varied with soil properties and land management. Results from this project, coupled with regional model simulations (Denitrification-Decomposition, DNDC) represent the baseline data needed for future voluntary carbon credit programs and long-term carbon monitoring networks. Enrollment in such programs could help ranchers and farmers realize a new income stream from maintaining their native prairie and the carbon stored beneath it.

  5. Impact of Carbon Quota Allocation Mechanism on Emissions Trading: An Agent-Based Simulation

    Directory of Open Access Journals (Sweden)

    Wei Jiang

    2016-08-01

    Full Text Available This paper establishes an agent-based simulation system of the carbon emissions trading in accordance with the complex feature of the trading process. This system analyzes the impact of the carbon quota allocation mechanism on emissions trading for three different aspects including the amount of emissions reduction, the economic effect on the emitters, and the emissions reduction cost. Based on the data of the carbon emissions of different industries in China, several simulations were made. The results indicate that the emissions trading policy can effectively reduce carbon emissions in a perfectly competitive market. Moreover, by comparing separate quota allocation mechanisms, we obtain the result that the scheme with a small extent quota decrease in a comprehensive allocation mechanism can minimize the unit carbon emission cost. Implementing this scheme can also achieve minimal effects of carbon emissions limitation on the economy on the basis that the environment is not destroyed. However, excessive quota decrease cannot promote the emitters to reduce emission. Taking into account that several developing countries have the dual task of limiting carbon emissions and developing the economy, it is necessary to adopt a comprehensive allocation mechanism of the carbon quota and increase the initial proportion of free allocation.

  6. Estimating belowground carbon stocks in isolated wetlands of the Northern Everglades Watershed, central Florida, using ground penetrating radar (GPR) and aerial imagery

    Science.gov (United States)

    McClellan, Matthew; Comas, Xavier; Hinkle, Ross; Sumner, David M.

    2017-01-01

    Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. While isolated freshwater wetlands in temperate and tropical biomes account for more than 20% of the global peatland C stock, most studies of wetland soil C have occurred in expansive peatlands in northern boreal and subarctic biomes. Furthermore, the contribution of small depressional wetlands in comparison to larger wetland systems in these environments is very uncertain. Given the fact that these wetlands are numerous and variable in terms of their internal geometry, innovative methods are needed for properly estimating belowground C stocks and their overall C contribution to the landscape. In this study, we use a combination of ground penetrating radar (GPR), aerial imagery, and direct measurements (coring) in conjunction with C core analysis to develop a relation between C stock and surface area, and estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods at the Disney Wilderness Preserve (DWP), Florida. Additionally, GPR surveys were able to image collapse structures underneath the peat basin of depressional wetlands, depicting lithological controls on the formation of depressional wetlands at the DWP. Results indicate the importance of depressional wetlands as critical contributors to the landscape C budget at the DWP and the potential of GPR-based approaches for (1) rapidly and noninvasively estimating the contribution of depressional wetlands to regional C stocks and (2) evaluating the formational processes of depressional wetlands.

  7. Estimating Belowground Carbon Stocks in Isolated Wetlands of the Northern Everglades Watershed, Central Florida, Using Ground Penetrating Radar and Aerial Imagery

    Science.gov (United States)

    McClellan, Matthew; Comas, Xavier; Benscoter, Brian; Hinkle, Ross; Sumner, David

    2017-11-01

    Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. While isolated freshwater wetlands in temperate and tropical biomes account for more than 20% of the global peatland C stock, most studies of wetland soil C have occurred in expansive peatlands in northern boreal and subarctic biomes. Furthermore, the contribution of small depressional wetlands in comparison to larger wetland systems in these environments is very uncertain. Given the fact that these wetlands are numerous and variable in terms of their internal geometry, innovative methods are needed for properly estimating belowground C stocks and their overall C contribution to the landscape. In this study, we use a combination of ground penetrating radar (GPR), aerial imagery, and direct measurements (coring) in conjunction with C core analysis to develop a relation between C stock and surface area, and estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods at the Disney Wilderness Preserve (DWP), Florida. Additionally, GPR surveys were able to image collapse structures underneath the peat basin of depressional wetlands, depicting lithological controls on the formation of depressional wetlands at the DWP. Results indicate the importance of depressional wetlands as critical contributors to the landscape C budget at the DWP and the potential of GPR-based approaches for (1) rapidly and noninvasively estimating the contribution of depressional wetlands to regional C stocks and (2) evaluating the formational processes of depressional wetlands.

  8. Warming-related increases in soil CO2 efflux are explained by increased below-ground carbon flux

    Science.gov (United States)

    Christian P. Giardina; Creighton M. Litton; Susan E. Crow; Gregory P Asner

    2014-01-01

    The universally observed exponential increase in soil-surface CO2 effux (‘soil respiration’; FS) with increasing temperature has led to speculation that global warming will accelerate soil organic carbon (SOC) decomposition, reduce SOC storage, and drive a positive feedback to future warming. However, interpreting temperature–FS relationships,...

  9. Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise

    OpenAIRE

    Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew S.; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; Almario, Alejandro E.

    2017-01-01

    Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove w...

  10. Effect of applied environmental stress on growth, photosynthesis, carbon allocation, and hydrocarbon production in Euphorbia lathyris

    International Nuclear Information System (INIS)

    Taylor, S.E.; Calvin, M.

    1988-01-01

    Photosynthetic activity was reduced by salinity stress, but is was found to be less sensitive than growth. Salinity stress also caused changes in the concentrations of specific cations. Moderate water stress had little effect on growth, but large changes in hydrocarbon production were still observed. Carbon allocation experiments with radiolabeled carbon indicated that carbon for latex production was supplied by nearby leaves, with some translocation down the stem also occurring

  11. Above and belowground connections and species interactions: Controls over ecosystem fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, Amy Marie [Montana State Univ., Bozeman, MT (United States); Phillips, Richard [Indiana Univ., Bloomington, IN (United States); Stoy, Paul Christopher [Montana State Univ., Bozeman, MT (United States)

    2016-11-01

    season. This research lays the foundation to answer important questions regarding the impacts of seasonality and forest composition on belowground volatile source-sink dynamics in mediating nutrient cycling and biogeochemistry dynamics—critical components of overall ecosystem functioning. In collaboration with the Environmental Simulations Unit (EUS) at the Helmholtz Zentrum in Munich, Germany (headed by Prof. Dr. Joerg-Peter Schinitzler), we investigated carbon investment in above and belowground plant volatile compounds in response to environmental conditions and mycorrhizal associations. Using the sophisticated phytotron facility and on-line trace gas instruments, we conducted controlled laboratory experiments that showed that biotic stresses, such as herbivore feeding, can alter the magnitude of belowground volatile emissions as well as carbon allocation towards these volatiles. We saw no effect of mycorrhizae on any induced response, suggesting that microbial effects were unrelated to source-sink dynamics driving terpene emissions. Furthermore, the results suggest that even though enzyme activity responsible for root volatile synthesis is up-regulated following herbivory, the sink strength of the soil can significantly impact what is measured at the soil/atmosphere interface and thereby what enters the atmosphere. This is important as scientists may be underestimating the magnitude of belowground volatile emissions and their influence on belowground interactions due to limitations associated with current sampling techniques. These key findings are being integrated with results from a hydroxyl radical reactivity-VOC campaign and a late season litter removal experiment to offer a comprehensive mechanistic understanding of the sources and controls over soil volatile emissions, particularly during times of the year when vegetative aboveground emissions are low (leaf senescence). Ultimately, these coupled field and laboratory experiments offer insights into seasonal

  12. Climate change affects carbon allocation to the soil in shrublands

    NARCIS (Netherlands)

    Gorissen, A.; Tietema, A.; Joosten, N.N.; Estiarte, M.; Peñuelas, J.; Sowerby, A.; Emmett, B.; Beier, J.C.

    2004-01-01

    Climate change may affect ecosystem functioning through increased temperatures or changes in precipitation patterns. Temperature and water availability are important drivers for ecosystem processes such as photosynthesis, carbon translocation, and organic matter decomposition. These climate changes

  13. Evaluating the effectiveness of mulch application to store carbon belowground: Short-term effects of mulch application on soluble soil and microbial C and N in agricultural soils with low and high organic matter

    Science.gov (United States)

    Chen, Janet; Heiling, Maria; Resch, Christian; Gruber, Roman; Dercon, Gerd

    2017-04-01

    Agricultural soils have the potential to contain a large pool of carbon and, depending on the farming techniques applied, can either effectively store carbon belowground, or further release carbon, in the form of CO2, into the atmosphere. Farming techniques, such as mulch application, are frequently proposed to increase carbon content belowground and improve soil quality and can be used in efforts to reduce greenhouse gas levels, such as in the "4 per 1000" Initiative. To test the effectiveness of mulch application to store carbon belowground in the short term and improve soil nutrient quality, we maintained agricultural soils with low and high organic carbon content (disturbed top soil from local Cambisols and Chernozems) in greenhouse mesocosms (70 cm deep with a radius of 25 cm) with controlled moisture for 4 years. Over the 4 years, maize and soybean were grown yearly in rotation and mulch was removed or applied to soils once plant material was harvested at 2 ton/ha dry matter. In addition, soil disturbance was kept to a minimum, with only surface disturbance of a few centimeters to keep soil free from weeds. After 4 years, we measured effects of mulch application on soluble soil and microbial carbon and nitrogen in the mesocosms and compared effects of mulch application versus no mulch on soils from 0-5 cm and 5-15 cm with low and high organic matter. We predicted that mulch would increase soil carbon and nitrogen content and mulch application would have a greater effect on soils with low organic matter than soils with high organic matter. In soils with low organic carbon content and larger predicted potential to increase soil carbon, mulch application did not increase soluble soil or microbial carbon or nitrogen compared to the treatments without mulch application. However, mulch application significantly increased the δ13C of both microbial and soluble soil carbon in these soils by 1 ‰ each, indicating a shift in belowground processes, such as increased

  14. Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise

    Science.gov (United States)

    Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; Almario, Alejandro E.

    2017-01-01

    Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr−1), with surface elevation change of 4.2–11.0 mm yr−1 compared with 1.5–7.2 mm yr−1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

  15. Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise.

    Science.gov (United States)

    Krauss, Ken W; Cormier, Nicole; Osland, Michael J; Kirwan, Matthew L; Stagg, Camille L; Nestlerode, Janet A; Russell, Marc J; From, Andrew S; Spivak, Amanda C; Dantin, Darrin D; Harvey, James E; Almario, Alejandro E

    2017-04-21

    Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr -1 ), with surface elevation change of 4.2-11.0 mm yr -1 compared with 1.5-7.2 mm yr -1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

  16. Allocation of carbon permits within a country. A general equilibrium analysis of the United Kingdom

    International Nuclear Information System (INIS)

    Edwards, T.H.; Hutton, J.P.

    2001-01-01

    The Kyoto agreement includes international trade in carbon permits from 2008. We have used a CGE model to evaluate methods of allocating permits within the UK. Auctioning is broadly similar to a carbon tax, with revenues recycled to reduce other distortions. 'Grandfathering' some permits free to large firms would mean a loss of recycling and, possibly, give windfall profits to foreigners. Alternatively, regularly revised allocation, using 'best practice' estimates, would be similar to recycling revenue as an output subsidy. Such a system could allow much of the potential 'double dividend' to be realised, though an auction system might still be preferable

  17. A carbon emissions reduction index: Integrating the volume and allocation of regional emissions

    International Nuclear Information System (INIS)

    Chen, Jiandong; Cheng, Shulei; Song, Malin; Wu, Yinyin

    2016-01-01

    Highlights: • We build a carbon emissions reduction index (CERI). • The aim is to quantify the pressure on policymakers to reduce emissions. • Scale-related effects and carbon emissions allocations are included in the CERI. • Different standards of carbon emissions allocations are also considered. • We decompose the Gini coefficient to evaluate the effects of three factors. - Abstract: Given the acceleration of global warming and rising greenhouse gas emissions, all countries are facing the harsh reality of the need to reduce carbon emissions. In this study, we propose an index to quantify the pressure faced by policymakers to reduce such emissions, termed the carbon emissions reduction index. This index allows us to observe the effect of carbon emissions volume on the pressure faced by policymakers and study the impact of optimizing interregional carbon emissions on reducing this pressure. In addition, we account for several carbon emissions standards in constructing the index. We conclude that the variation in the index is likely to be attributable to carbon emissions volume, regional ranking, and population (population can also be replaced by GDP, resource endowment, or other factors). In addition, based on empirical data on the world’s largest emitter of carbon dioxide (China), this study analyzes the evolution of pressure to reduce emissions on a country’s policymakers. The results show that the growing volume and unsuitable allocation of carbon emissions from 1997 to 2012 imposed increasing pressure on the Chinese government in this regard. In addition, reductions in carbon emissions volume and regional ranking are primary factors that impact pressure on policymakers.

  18. Initial Provincial Allocation and Equity Evaluation of China’s Carbon Emission Rights—Based on the Improved TOPSIS Method

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2018-03-01

    Full Text Available As the world’s largest carbon emitter, China considers carbon emissions trading to be an important measure in its national strategy for energy conservation and emissions reduction. The initial allocation of China’s carbon emissions rights at the provincial level is a core issue of carbon emissions trading. A scientific and reasonable distinction between the carbon emission rights of provinces is crucial for China to achieve emissions reduction targets. Based on the idea of multi-objective decision-making, this paper uses the improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS method to allocate China’s initial carbon emission rights to the provinces and uses the Gini coefficient sub-group decomposition method to evaluate the fairness of the allocation results. First, the results of a theoretical distribution show that in the initial allocation of carbon emission rights, a large proportion of China’s provinces have large populations and high energy use, such as Shandong Province, Jiangsu Province, Hebei Province and Henan Province; the provinces with a small proportion of the initial allocation of carbon emissions consist of two municipalities, Beijing and Shanghai, as well as Hainan Province, which is dominated by tourism. Overall, the initial allocation of carbon emission rights in the northern and eastern regions constituted the largest proportion, with the south-central region and the northwest region being the second largest and the southwest region being the smallest. Second, the difference between the theoretical allocation and the actual allocation of carbon emission rights in China was clear. The energy consumption of large provinces and provinces dominated by industry generally had a negative difference (the theoretical allocation of carbon emissions was less than the actual value, while Qinghai, dominated by agriculture and animal husbandry, showed a positive balance (the theoretical allocation of

  19. Tendances Carbone no. 79 'Free allocations under Phase 3 benchmarks: early evidence of what has changed'

    International Nuclear Information System (INIS)

    Sartor, Oliver

    2013-01-01

    Among the publications of CDC Climat Research, 'Tendances Carbone' bulletin specifically studies the developments of the European market for CO 2 allowances. This issue addresses the following points: One of the most controversial changes to the EU ETS in Phase 3 (2013-2020) has been the introduction of emissions-performance benchmarks for determining free allocations to non-electricity producers. Phases 1 and 2 used National Allocation Plans (NAPs). For practical reasons NAPs were drawn up by each Member State, but this led to problems, including over-generous allowance allocation, insufficiently harmonised allocations across countries and distorted incentives to reduce emissions. Benchmarking tries to fix things by allocating the equivalent of 100% of allowances needed if every installation used the best available technology. But this is not universally popular and industries say that they might lose international competitiveness. So a new study by CDC Climat and the Climate Economics Chair examined the data from the preliminary Phase 3 free allocations of 20 EU Member States and asked: how much are free allocations actually going to change with benchmarking?

  20. Carbon emission allowance allocation with a mixed mechanism in air passenger transport.

    Science.gov (United States)

    Qiu, Rui; Xu, Jiuping; Zeng, Ziqiang

    2017-09-15

    Air passenger transport carbon emissions have become a great challenge for both governments and airlines because of rapid developments in the aviation industry in recent decades. In this paper, a mixed mechanism composed of a cap-and-trade mechanism and a carbon tax mechanism is developed to assist governments in allocating carbon emission allowances to airlines operating on the routes. Combined this mixed mechanism with an equilibrium strategy, a bi-level multi-objective model is proposed for an air passenger transport carbon emission allowance allocation problem, in which a government is considered as a leader and the airlines as the followers. An interactive solution approach integrating a genetic algorithm and an interactive evolutionary mechanism is designed to search for satisfactory solutions of the proposed model. A case study is then presented to show its practicality and efficiency in mitigating carbon emissions. Sensitivity analyses under different tradable and taxable levels are also conducted, which can give the government insights as to the tradeoffs between lowering carbon intensity and improving airlines' operations. The computational results demonstrate that the mixed mechanism can assist greatly in carbon emission mitigation for air passenger transport and therefore, it should be established as part of air passenger transport carbon emission policies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A comparison of carbon allocation schemes: On the equity-efficiency tradeoff

    International Nuclear Information System (INIS)

    Pan, Xunzhang; Teng, Fei; Wang, Gehua

    2014-01-01

    In the long-term stabilization targets of greenhouse gases concentrations, various carbon emission rights allocation schemes have been proposed. To compare and evaluate them, the most essential is the equity-efficiency tradeoff. This paper measures the equity and the efficiency in the global rather than the narrower national perspective. Specifically, the equity of the first allocation is quantified by the carbon Gini coefficient defined by per capita cumulative emission, and the economic efficiency to accomplish obligations is described with the discounted global abatement costs. Under 20 key allocation schemes, the numerical comparison on the equity-efficiency tradeoff side is carried out through the Equitable Access to Sustainable Development model. Our studies indicate that the equity and the efficiency of future emission space allocation approximately show a three-stage relationship. - Highlights: • The equity-efficiency tradeoff among 20 key allocation schemes is carried out. • Both the equity and the efficiency are measured in the global perspective. • The Equitable Access to Sustainable Development model is adopted as the study tool. • A practical trade framework is indispensable to efficiently address climate change. • The equity and the efficiency generally show a three-stage tradeoff relationship

  2. Tracer kinetics of plants carbon allocation with continuously produced 11CO2

    International Nuclear Information System (INIS)

    Fares, Y.; Goeschl, J.D.; Magnuson, C.E.; Strain, B.R.

    1988-01-01

    Parameters of carbon allocation dynamics in plants were measured using 11 CO 2 and tracer kinetics techniques. Mechanical agitation reduced carbon export rate (CER) by 33% in cotton seedling's leaf, while storage rate and export pool size increased. Carbon storage and export rates of C 4 bunch grasses were higher in the afternoon than in the morning in spite of the decrease in CER. Water stress of cotton seedlings caused reduction in CER, and increase in exportable products concentrations and rate of storage. By the third stress day, measurable decreases in CER, transpiration, export rate and export pool size were recorded. (author) 17 refs.; 8 figs.; 1 tab

  3. Mind the Roots: Phenotyping Below-Ground Crop Diversity and Its Influence on Final Yield

    Science.gov (United States)

    Nieters, C.; Guadagno, C. R.; Lemli, S.; Hosseini, A.; Ewers, B. E.

    2017-12-01

    Changes in global climate patterns and water regimes are having profound impacts on worldwide crop production. An ever-growing population paired with increasing temperatures and unpredictable periods of severe drought call for accurate modeling of future crop yield. Although novel approaches are being developed in high-throughput, above-ground image phenotyping, the below-ground plant system is still poorly phenotyped. Collection of plant root morphology and hydraulics are needed to inform mathematical models to reliably estimate yields of crops grown in sub-optimal conditions. We used Brassica rapa to inform our model as it is a globally cultivated crop with several functionally diverse cultivars. Specifically, we use 7 different accessions from oilseed (R500 and Yellow Sarson), leafy type (Pac choi and Chinese cabbage), a vegetable turnip, and two Wisconsin Fast Plants (Imb211 and Fast Plant self-compatible), which have shorter life cycles and potentially large differences in allocation to roots. Bi-weekly, we harvested above and below-ground biomass to compare the varieties in terms of carbon allocation throughout their life cycle. Using WinRhizo software, we analyzed root system length and surface area to compare and contrast root morphology among cultivars. Our results confirm that root structural characteristics are crucial to explain plant water use and carbon allocation. The root:shoot ratio reveals a significant (p physiological traits such as gas exchange, chlorophyll content, and chlorophyll a fluorescence. A thorough analysis of the root system will clarify carbon dynamics and hydraulics at the whole-plant level, improving final yield predictions.

  4. Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests

    Science.gov (United States)

    Lapenis, Andrei Gennady; Lawrence, Gregory B.; Heim, Alexander; Zheng, Chengyang; Shortle, Walter

    2013-01-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

  5. Provincial Carbon Emissions Reduction Allocation Plan in China Based on Consumption Perspective

    Directory of Open Access Journals (Sweden)

    Xuecheng Wang

    2018-04-01

    Full Text Available China is a country with substantial differences in economic development, energy consumption mix, resources, and technologies, as well as the development path at the provincial level. Therefore, China’s provinces have different potential and degrees of difficulty to carry out carbon emission reduction (CER requirements. In addition, interprovincial trade, with a large amount of embodied carbon emissions, has become the fastest growing driver of China’s total carbon emissions. A reasonable CER allocation plan is, therefore, crucial for realizing the commitment that China announced in the Paris Agreement. How to determine a fair way to allocate provincial CER duties has become a significant challenge for both policy-makers and researchers. In this paper, ecological network analysis (ENA, combined with a multi-regional input-output model (MRIO, is adopted to build an ecological network of embodied emissions across 30 provinces. Then, by using flow analysis and utility analysis based on the ENA model, the specific relationships among different provinces were determined, and the amount of responsibility that a certain province should take quantified, with respect to the embodied carbon emission (ECE flows from interprovincial trade. As a result, we suggest a new CER allocation plan, based on the detailed data of interprovincial relationships and ECE flows.

  6. A hybrid method for provincial scale energy-related carbon emission allocation in China.

    Science.gov (United States)

    Bai, Hongtao; Zhang, Yingxuan; Wang, Huizhi; Huang, Yanying; Xu, He

    2014-01-01

    Achievement of carbon emission reduction targets proposed by national governments relies on provincial/state allocations. In this study, a hybrid method for provincial energy-related carbon emissions allocation in China was developed to provide a good balance between production- and consumption-based approaches. In this method, provincial energy-related carbon emissions are decomposed into direct emissions of local activities other than thermal power generation and indirect emissions as a result of electricity consumption. Based on the carbon reduction efficiency principle, the responsibility for embodied emissions of provincial product transactions is assigned entirely to the production area. The responsibility for carbon generation during the production of thermal power is borne by the electricity consumption area, which ensures that different regions with resource endowments have rational development space. Empirical studies were conducted to examine the hybrid method and three indices, per capita GDP, resource endowment index and the proportion of energy-intensive industries, were screened to preliminarily interpret the differences among China's regional carbon emissions. Uncertainty analysis and a discussion of this method are also provided herein.

  7. Browsing affects intra-ring carbon allocation in species with contrasting wood anatomy.

    Science.gov (United States)

    Palacio, S; Paterson, E; Sim, A; Hester, A J; Millard, P

    2011-02-01

    Current knowledge on tree carbon (C) allocation to wood is particularly scarce in plants subjected to disturbance factors, such as browsing, which affects forest regeneration worldwide and has an impact on the C balance of trees. Furthermore, quantifying the degree to which tree rings are formed from freshly assimilated vs. stored carbohydrates is highly relevant for our understanding of tree C allocation. We used (13)C labelling to quantify seasonal allocation of stored C to wood formation in two species with contrasting wood anatomy: Betula pubescens Ehrh. (diffuse-porous) and Quercus petraea [Matt.] Liebl. (ring-porous). Clipping treatments (66% shoot removal, and unclipped) were applied to analyse the effect of browsing on C allocation into tree rings, plus the effects on tree growth, architecture, ring width and non-structural carbohydrates (NSCs). The relative contribution of stored C to wood formation was greater in the ring-porous (55-70%) than in the diffuse-porous species (35-60%), although each species followed different seasonal trends. Clipping did not cause a significant depletion of C stores in either species. Nonetheless, a significant increase in the proportion of stored C allocated to earlywood growth was observed in clipped birches, and this could be explained through changes in tree architecture after clipping. The size of C pools across tree species seems to be important in determining the variability of seasonal C allocation patterns to wood and their sensibility to disturbances such as browsing. Our results indicate that the observed changes in C allocation to earlywood in birch were not related to variations in the amount or concentration of NSC stores, but to changes in the seasonal availability of recently assimilated C caused by modifications in tree architecture after browsing.

  8. Silver birch and climate change: variable growth and carbon allocation responses to elevated concentrations of carbon dioxide and ozone

    International Nuclear Information System (INIS)

    Riikonen, J.; Holopainen, T.; Oksanen, E.; Lindsberg, M-M.; Lappi, J.; Peltonen, P.; Vapaavuori, E.

    2004-01-01

    The effects of elevated concentrations of carbon dioxide and ozone were studied on growth, biomass allocation and leaf area of field-grown ozone-tolerant (Clone 4) and ozone-sensitive (Clone 80) European silver birch trees. Seven-year old trees of both types were exposed for three years to outside and chamber control, (1) twice ambient ozone, (2) twice ambient carbon dioxide, and (3) twice ambient carbon dioxide and twice ambient ozone. No effect on biomass allocation was observed when results of the two clones were analyzed together. Total leaf area showed an increase, and leaf abscission appeared delayed in response to elevated carbon dioxide. Elevated ozone caused the dry mass of roots, branches and mean leaf size to decrease, and autumnal leaf abscission occurred earlier than usual in both clones. In general. the effects of elevated ozone were small, however, the interaction between elevated carbon dioxide and elevated oxygen were significant. When results from the two clones were analyzed separately, stem diameter, volume growth and total biomass of Clone 80 increased when exposed to elevated concentrations of carbon dioxide; elevated concentrations of ozone appeared to have no effect. In Clone 4 elevated ozone caused significant decrease in root and branch biomass, but the effects of elevated carbon dioxide were minimal. Responses to elevated ozone exposure were observed only under ambient carbon dioxide conditions. This response is believed to reflect the greater quantity of carbohydrates available for detoxification and repair under elevated carbon dioxide conditions. Alternatively, the response may be due to decreased stomatal conductance, thus decreased ozone uptake under elevated carbon dioxide conditions. 45 refs., 6 tabs., 4 figs

  9. Estimation of carbon allocation of Macauba palm (Acrocomia aculeata) - A new Brazilian biofuel alternative

    Science.gov (United States)

    Imbuzeiro, H. A.; Moreira, S. L. S.; Motoike, S. Y.; Fernandes, R. B. A.

    2017-12-01

    The Macauba palm (Acrocomia aculeata (Jacq.) Lood. ex Mart) is a native oil palm of the tropical America growing in anthropic areas, especially in grazing lands of Brazilian Cerrado. Macauba palm displays intense fruiting which results in high fruit and oil yield (3.0 - 6.0 ton/ha/year). The main Macauba palm differentials are: it is adapted to the environment with marked water restriction (1000 mm annual precipitation) which makes it resistant to drought and it does not compete with areas of rainforest; the oil is similar in composition to the African palm oil (Elaeis guineensis Jacq.) and can be used in several industrial applications such as biofuels, food, cosmetics, pharmaceutics and oil chemistry. Additionally, Macauba fruit processing generates several by-products like edible pulp bran, high-protein edible kernel bran, dense endocarp biomass, and husk biomass, all valuable products. Today, 172 million hectares of Brazilian land are used for grazing, of which 30 million hectares of these lands are degraded due to poor land use, 6 million in the state of Minas Gerais, in Brazil. Macauba could be cultivated in these degraded lands and is a candidate to become the main raw material for production of biokerosene. A new productive chain is forming in Brazil, the first commercial plantation of Macauba was implemented last year in Minas Gerais state and it is important to estimate the environmental impacts of this plantation, in terms of carbon (C) allocation. There is a lack of experimental data on Macauba carbon allocation and this study aimed to estimate the carbon allocation (leaves, stems and roots) of Macauba palm. The results suggest that Macauba palm is important in contributing to the carbon allocation.

  10. Ecosystem carbon density and allocation across a chronosequence of longleaf pine forests.

    Science.gov (United States)

    Samuelson, Lisa J; Stokes, Thomas A; Butnor, John R; Johnsen, Kurt H; Gonzalez-Benecke, Carlos A; Martin, Timothy A; Cropper, Wendell P; Anderson, Pete H; Ramirez, Michael R; Lewis, John C

    2017-01-01

    Forests can partially offset greenhouse gas emissions and contribute to climate change mitigation, mainly through increases in live biomass. We quantified carbon (C) density in 20 managed longleaf pine (Pinus palustris Mill.) forests ranging in age from 5 to 118 years located across the southeastern United States and estimated above- and belowground C trajectories. Ecosystem C stock (all pools including soil C) and aboveground live tree C increased nonlinearly with stand age and the modeled asymptotic maxima were 168 Mg C/ha and 80 Mg C/ha, respectively. Accumulation of ecosystem C with stand age was driven mainly by increases in aboveground live tree C, which ranged from ecosystem C. Live root C (sum of below-stump C, ground penetrating radar measurement of lateral root C, and live fine root C) increased with stand age and represented 4-22% of ecosystem C. Soil C was related to site index, but not to stand age, and made up 39-92% of ecosystem C. Live understory C, forest floor C, downed dead wood C, and standing dead wood C were small fractions of ecosystem C in these frequently burned stands. Stand age and site index accounted for 76% of the variation in ecosystem C among stands. The mean root-to-shoot ratio calculated as the average across all stands (excluding the grass-stage stand) was 0.54 (standard deviation of 0.19) and higher than reports for other conifers. Long-term accumulation of live tree C, combined with the larger role of belowground accumulation of lateral root C than in other forest types, indicates a role of longleaf pine forests in providing disturbance-resistant C storage that can balance the more rapid C accumulation and C removal associated with more intensively managed forests. Although other managed southern pine systems sequester more C over the short-term, we suggest that longleaf pine forests can play a meaningful role in regional forest C management. © 2016 by the Ecological Society of America.

  11. Net carbon allocation in soybean seedlings as influenced by soil water stress at two soil temperatures

    International Nuclear Information System (INIS)

    McCoy, E.L.; Boersma, L.; Ekasingh, M.

    1990-01-01

    The influence of water stress at two soil temperatures on allocation of net photoassimilated carbon in soybean (Glycine max [L.] Merr.) was investigated using compartmental analysis. The experimental phase employed classical 14 C labeling methodology with plants equilibrated at soil water potentials of -0.04, -0.25 and -0.50 MPa; and soil temperatures of 25 and 10C. Carbon immobilization in the shoot apex generally followed leaf elongation rates with decreases in both parameters at increasing water stress at both soil temperatures. However, where moderate water stress resulted in dramatic declines in leaf elongation rates, carbon immobilization rates were sharply decreased only at severe water stress levels. Carbon immobilization was decreased in the roots and nodules of the nonwater stressed treatment by the lower soil temperature. This relation was reversed with severe water stress, and carbon immobilization in the roots and nodules was increased at the lower soil temperature. Apparently, the increased demand for growth and/or carbon storage in these tissues with increased water stress overcame the low soil temperature limitations. Both carbon pool sizes and partitioning of carbon to the sink tissues increased with moderate water stress at 25C soil temperature. Increased pool sizes were consistent with whole plant osmotic adjustment at moderate water stress. Increased partitioning to the sinks was consistent with carbon translocation processes being less severely influenced by water stress than is photosynthesis

  12. Spatially resolved metabolic analysis reveals a central role for transcriptional control in carbon allocation to wood.

    Science.gov (United States)

    Roach, Melissa; Arrivault, Stéphanie; Mahboubi, Amir; Krohn, Nicole; Sulpice, Ronan; Stitt, Mark; Niittylä, Totte

    2017-06-15

    The contribution of transcriptional and post-transcriptional regulation to modifying carbon allocation to developing wood of trees is not well defined. To clarify the role of transcriptional regulation, the enzyme activity patterns of eight central primary metabolism enzymes across phloem, cambium, and developing wood of aspen (Populus tremula L.) were compared with transcript levels obtained by RNA sequencing of sequential stem sections from the same trees. Enzymes were selected on the basis of their importance in sugar metabolism and in linking primary metabolism to lignin biosynthesis. Existing enzyme assays were adapted to allow measurements from ~1 mm3 sections of dissected stem tissue. These experiments provided high spatial resolution of enzyme activity changes across different stages of wood development, and identified the gene transcripts probably responsible for these changes. In most cases, there was a clear positive relationship between transcripts and enzyme activity. During secondary cell wall formation, the increases in transcript levels and enzyme activities also matched with increased levels of glucose, fructose, hexose phosphates, and UDP-glucose, emphasizing an important role for transcriptional regulation in carbon allocation to developing aspen wood. These observations corroborate the efforts to increase carbon allocation to wood by engineering gene regulatory networks. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. Uncovering the Driving Factors of Carbon Emissions in an Investment Allocation Model of China’s High-Carbon and Low-Carbon Energy

    Directory of Open Access Journals (Sweden)

    Shumin Jiang

    2017-06-01

    Full Text Available In the view of long-term comprehensive development, the concept of low-carbon economy has long been a concern. In this paper, we build a pure energy-economic system and explore the exact influencing factors in the investment allocation of high-carbon and low-carbon energy with the purpose of mitigating carbon dioxide in the atmosphere. The dynamic analysis shows that the model that we built is applicable for the current market situation and the way we adjust the investments of high-carbon and low-carbon energy are conductive to carbon abatement in the atmosphere. On the basis of the stability analysis and numerical simulation, some strategies are given to decrease the carbon dioxide in the atmosphere. The results show that the social consumption and public consumption behavior are the most important factors responsible for the variation in the atmospheric carbon dioxide. The cleanliness of high carbon presents an obvious mitigating effect on carbon in the atmosphere and the effect of marginal profit of high-carbon energy is the weakest. In addition, enhancing marginal profit, return on investment and investment share of low-carbon energy are beneficial to reduce carbon dioxide in the atmosphere, while a return on investment of high-carbon energy increasing is the detriment of the carbon dioxide in the atmosphere. Finally, we provide carbon mitigation effort by considering both economic development and carbon abatement for policymakers to achieve a desirable emission-reduction effect.

  14. The effect of carbon supply on allocation to allelochemicals and caterpillar consumption of peppermint.

    Science.gov (United States)

    Lincoln, D E; Couvet, D

    1989-01-01

    The carbon supply of peppermint plants was manipulated by growing clonal propagules under three carbon dioxide regimes (350, 500 and 650 μl l -1 ). Feeding by fourth instar caterpillars of Spodoptera eridania increased with elevated CO 2 hostplant regime, as well as with low leaf nitrogen content and by a high proportion of leaf volatile terpenoids. Leaf weight increased significantly with the increased carbon supply, but the amount of nitrogen per leaf did not change. The amount of volatile leaf mono-and sesquiterpenes increased proportionately with total leaf dry weight and hence was not influenced by CO 2 supply. These results are consistent with ecological hypotheses which assume that allocation to defense is closely regulated and not sensitive to carbon supply per se.

  15. Impact of interspecific competition and drought on the allocation of new assimilates in trees.

    Science.gov (United States)

    Hommel, R; Siegwolf, R; Zavadlav, S; Arend, M; Schaub, M; Galiano, L; Haeni, M; Kayler, Z E; Gessler, A

    2016-09-01

    In trees, the interplay between reduced carbon assimilation and the inability to transport carbohydrates to the sites of demand under drought might be one of the mechanisms leading to carbon starvation. However, we largely lack knowledge on how drought effects on new assimilate allocation differ between species with different drought sensitivities and how these effects are modified by interspecific competition. We assessed the fate of (13) C labelled assimilates in above- and belowground plant organs and in root/rhizosphere respired CO2 in saplings of drought-tolerant Norway maple (Acer platanoides) and drought-sensitive European beech (Fagus sylvatica) exposed to moderate drought, either in mono- or mixed culture. While drought reduced stomatal conductance and photosynthesis rates in both species, both maintained assimilate transport belowground. Beech even allocated more new assimilate to the roots under moderate drought compared to non-limited water supply conditions, and this pattern was even more pronounced under interspecific competition. Even though maple was a superior competitor compared to beech under non-limited soil water conditions, as indicated by the changes in above- and belowground biomass of both species in the interspecific competition treatments, we can state that beech was still able to efficiently allocate new assimilate belowground under combined drought and interspecific competition. This might be seen as a strategy to maintain root osmotic potential and to prioritise root functioning. Our results thus show that beech tolerates moderate drought stress plus competition without losing its ability to supply belowground tissues. It remains to be explored in future work if this strategy is also valid during long-term drought exposure. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Carbon stock projection in North Sumatera using multi objective land allocation approach

    Science.gov (United States)

    Ichwani, S. N.; Wulandari, R.; Ramachandra, A.

    2018-05-01

    Nowadays, GHG emission is a critical issue for environmental management due to the large scale of land cover change, especially forest cover. This study provides a protection development strategy for North Sumatera as one way to manage the area. By using Multi Objective Land Allocation (MOLA), we evaluated two GHG emission scenarios, including a Business As Usual (BAU) scenario and Protection scenario. The result shows that the province will lose the carbon stock up to 24 million tons in the year of 2035 by using a BAU scenario. On the other hand, by implementing the Protection scenario, total carbon stock that is lost in the same period is about 5 millions tons solely. It proves that protection scenario is a good scenario and effective to reduce the carbon loss. Furthermore, this scenario can be an alternative for North Sumatera spatial plan.

  17. Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

    Science.gov (United States)

    Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

    2016-04-01

    Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment. © 2015 John Wiley & Sons Ltd.

  18. Sensitivity of ring growth and carbon allocation to climatic variation vary within ponderosa pine trees.

    Science.gov (United States)

    Kerhoulas, Lucy P; Kane, Jeffrey M

    2012-01-01

    Most dendrochronological studies focus on cores sampled from standard positions (main stem, breast height), yet vertical gradients in hydraulic constraints and priorities for carbon allocation may contribute to different growth sensitivities with position. Using cores taken from five positions (coarse roots, breast height, base of live crown, mid-crown branch and treetop), we investigated how radial growth sensitivity to climate over the period of 1895-2008 varies by position within 36 large ponderosa pines (Pinus ponderosa Dougl.) in northern Arizona. The climate parameters investigated were Palmer Drought Severity Index, water year and monsoon precipitation, maximum annual temperature, minimum annual temperature and average annual temperature. For each study tree, we generated Pearson correlation coefficients between ring width indices from each position and six climate parameters. We also investigated whether the number of missing rings differed among positions and bole heights. We found that tree density did not significantly influence climatic sensitivity to any of the climate parameters investigated at any of the sample positions. Results from three types of analyses suggest that climatic sensitivity of tree growth varied with position height: (i) correlations of radial growth and climate variables consistently increased with height; (ii) model strength based on Akaike's information criterion increased with height, where treetop growth consistently had the highest sensitivity and coarse roots the lowest sensitivity to each climatic parameter; and (iii) the correlation between bole ring width indices decreased with distance between positions. We speculate that increased sensitivity to climate at higher positions is related to hydraulic limitation because higher positions experience greater xylem tensions due to gravitational effects that render these positions more sensitive to climatic stresses. The low sensitivity of root growth to all climatic variables

  19. Ecophysiological modeling of photosynthesis and carbon allocation to the tree stem in the boreal forest

    Directory of Open Access Journals (Sweden)

    F. Gennaretti

    2017-11-01

    Full Text Available A better understanding of the coupling between photosynthesis and carbon allocation in the boreal forest, together with its associated environmental factors and mechanistic rules, is crucial to accurately predict boreal forest carbon stocks and fluxes, which are significant components of the global carbon budget. Here, we adapted the MAIDEN ecophysiological forest model to consider important processes for boreal tree species, such as nonlinear acclimation of photosynthesis to temperature changes, canopy development as a function of previous-year climate variables influencing bud formation and the temperature dependence of carbon partition in summer. We tested these modifications in the eastern Canadian taiga using black spruce (Picea mariana (Mill. B.S.P. gross primary production and ring width data. MAIDEN explains 90 % of the observed daily gross primary production variability, 73 % of the annual ring width variability and 20–30 % of its high-frequency component (i.e., when decadal trends are removed. The positive effect on stem growth due to climate warming over the last several decades is well captured by the model. In addition, we illustrate how we improve the model with each introduced model adaptation and compare the model results with those of linear response functions. Our results demonstrate that MAIDEN simulates robust relationships with the most important climate variables (those detected by classical response-function analysis and is a powerful tool for understanding how environmental factors interact with black spruce ecophysiology to influence present-day and future boreal forest carbon fluxes.

  20. Ecophysiological modeling of photosynthesis and carbon allocation to the tree stem in the boreal forest

    Science.gov (United States)

    Gennaretti, Fabio; Gea-Izquierdo, Guillermo; Boucher, Etienne; Berninger, Frank; Arseneault, Dominique; Guiot, Joel

    2017-11-01

    A better understanding of the coupling between photosynthesis and carbon allocation in the boreal forest, together with its associated environmental factors and mechanistic rules, is crucial to accurately predict boreal forest carbon stocks and fluxes, which are significant components of the global carbon budget. Here, we adapted the MAIDEN ecophysiological forest model to consider important processes for boreal tree species, such as nonlinear acclimation of photosynthesis to temperature changes, canopy development as a function of previous-year climate variables influencing bud formation and the temperature dependence of carbon partition in summer. We tested these modifications in the eastern Canadian taiga using black spruce (Picea mariana (Mill.) B.S.P.) gross primary production and ring width data. MAIDEN explains 90 % of the observed daily gross primary production variability, 73 % of the annual ring width variability and 20-30 % of its high-frequency component (i.e., when decadal trends are removed). The positive effect on stem growth due to climate warming over the last several decades is well captured by the model. In addition, we illustrate how we improve the model with each introduced model adaptation and compare the model results with those of linear response functions. Our results demonstrate that MAIDEN simulates robust relationships with the most important climate variables (those detected by classical response-function analysis) and is a powerful tool for understanding how environmental factors interact with black spruce ecophysiology to influence present-day and future boreal forest carbon fluxes.

  1. Starch as a source, starch as a sink: the bifunctional role of starch in carbon allocation.

    Science.gov (United States)

    MacNeill, Gregory J; Mehrpouyan, Sahar; Minow, Mark A A; Patterson, Jenelle A; Tetlow, Ian J; Emes, Michael J

    2017-07-20

    Starch commands a central role in the carbon budget of the majority of plants on earth, and its biological role changes during development and in response to the environment. Throughout the life of a plant, starch plays a dual role in carbon allocation, acting as both a source, releasing carbon reserves in leaves for growth and development, and as a sink, either as a dedicated starch store in its own right (in seeds and tubers), or as a temporary reserve of carbon contributing to sink strength, in organs such as flowers, fruits, and developing non-starchy seeds. The presence of starch in tissues and organs thus has a profound impact on the physiology of the growing plant as its synthesis and degradation governs the availability of free sugars, which in turn control various growth and developmental processes. This review attempts to summarize the large body of information currently available on starch metabolism and its relationship to wider aspects of carbon metabolism and plant nutrition. It highlights gaps in our knowledge and points to research areas that show promise for bioengineering and manipulation of starch metabolism in order to achieve more desirable phenotypes such as increased yield or plant biomass. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. An Optimal Allocation Model of Public Transit Mode Proportion for the Low-Carbon Transportation

    Directory of Open Access Journals (Sweden)

    Linjun Lu

    2015-01-01

    Full Text Available Public transit has been widely recognized as a potential way to develop low-carbon transportation. In this paper, an optimal allocation model of public transit mode proportion (MPMP has been built to achieve the low-carbon public transit. Optimal ratios of passenger traffic for rail, bus, and taxi are derived by running the model using typical data. With different values of traffic demand, construction cost, travel time, and accessibilities, MPMP can generate corresponding optimal ratios, benefiting decision impacts analysis and decision makers. Instead of considering public transit as a united system, it is separated into units in this paper. And Shanghai is used to test model validity and practicality.

  3. Improving representation of nitrogen uptake, allocation, and carbon assimilation in the Community Land Model

    Science.gov (United States)

    Ghimire, B.; Riley, W. J.; Koven, C.

    2013-12-01

    Nitrogen is the most important nutrient limiting plant carbon assimilation and growth, and is required for production of photosynthetic enzymes, growth and maintenance respiration, and maintaining cell structure. The forecasted rise in plant available nitrogen through atmospheric nitrogen deposition and the release of locked soil nitrogen by permafrost thaw in high latitude ecosystems is likely to result in an increase in plant productivity. However a mechanistic representation of plant nitrogen dynamics is lacking in earth system models. Most earth system models ignore the dynamic nature of plant nutrient uptake and allocation, and further lack tight coupling of below- and above-ground processes. In these models, the increase in nitrogen uptake does not translate to a corresponding increase in photosynthesis parameters, such as maximum Rubisco capacity and electron transfer rate. We present an improved modeling framework implemented in the Community Land Model version 4.5 (CLM4.5) for dynamic plant nutrient uptake, and allocation to different plant parts, including leaf enzymes. This modeling framework relies on imposing a more realistic flexible carbon to nitrogen stoichiometric ratio for different plant parts. The model mechanistically responds to plant nitrogen uptake and leaf allocation though changes in photosynthesis parameters. We produce global simulations, and examine the impacts of the improved nitrogen cycling. The improved model is evaluated against multiple observations including TRY database of global plant traits, nitrogen fertilization observations and 15N tracer studies. Global simulations with this new version of CLM4.5 showed better agreement with the observations than the default CLM4.5-CN model, and captured the underlying mechanisms associated with plant nitrogen cycle.

  4. Measurement of carbon fixation and allocation using 11C-labeled carbon dioxide

    International Nuclear Information System (INIS)

    Strain, B.R.; Goeschl, J.D.; Jaeger, C.H.; Fares, Y.; Magnuson, C.E.; Nelson, C.E.

    1983-01-01

    This paper describes the use of continuously produced and applied 11 C in measurements of carbon dioxide assimilation and C movement in plant research. This technique differs from the pulsing type 11 C research underway in other laboratories by being continuous and on-line with computer analysis making steady-state measurements of carbon fixation and movement possible. The studies to be described here make clear the advantages of using continuously produced and applied short half-lived isotopes

  5. Growing up with stress - carbon sequestration and allocation dynamics of a broadleaf evergreen forest

    Science.gov (United States)

    Griebel, Anne; Bennett, Lauren T.; Arndt, Stefan K.

    2016-04-01

    Evergreen forests have the potential to sequester carbon year-round due to the presence of leaves with a multi-year lifespan. Eucalypt forests occur in warmer climates where temperature and radiation are not imposing a strong seasonality. Thus, unlike deciduous or many coniferous trees, many eucalypts grow opportunistically as conditions allow. As such, many eucalypts do not produce distinct growth rings, which present challenges to the implementation of standard methods and data interpretation approaches for monitoring and explaining carbon allocation dynamics in response to climatic stress. As a consequence, there is a lack of detailed understanding of seasonal growth dynamics of evergreen forests as a whole, and, in particular, of the influence of climatic drivers on carbon allocation to the various biomass pools. We used a multi-instrument approach in a mixed species eucalypt forest to investigate the influence of climatic drivers on the seasonal growth dynamics of a predominantly temperate and moisture-regulated environment in south-eastern Australia. Ecosystem scale observations of net ecosystem exchange (NEE) from a flux tower in the Wombat forest near Melbourne indicated that the ecosystem is a year-round carbon sink, but that intra-annual variations in temperature and moisture along with prolonged heat waves and dry spells resulted in a wide range of annual sums over the past three years (NEE ranging from ~4 to 12 t C ha-1 yr-1). Dendrometers were used to monitor stem increments of the three dominant eucalypt species. Stem expansion was generally opportunistic with the greatest increments under warm but moist conditions (often in spring and autumn), and the strongest indicators of stem growth dynamics being radiation, vapour pressure deficit and a combined heat-moisture index. Differences in the seasonality of stem increments between species were largely due to differences in the canopy position of sampled individuals. The greatest stem increments were

  6. Factors controlling Eucalyptus productivity: How water availability and stand structure alter production and carbon allocation

    Science.gov (United States)

    Michael G. Ryan; Jose Luiz Stape; Dan Binkley; Sebastiao Fonseca; Rodolfo A. Loos; Ernesto N. Takahashi; Claudio R. Silva; Sergio R. Silva; Rodrigo E. Hakamada; Jose Mario Ferreira; Augusto M. N. Lima; Jose Luiz Gava; Fernando P. Leite; Helder B. Andrade; Jacyr M. Alves; Gualter G. C. Silva

    2010-01-01

    Wood production varies substantially with resource availability, and the variation in wood production can result from several mechanisms: increased photosynthesis, and changes in partitioning of photosynthesis to wood production, belowground flux, foliage production or respiration. An understanding of the mechanistic basis for patterns in wood production...

  7. Direct in situ measurement of Carbon Allocation to Mycorrhizal Fungi in a California Mixed-Conifer Forest

    Science.gov (United States)

    Allen, M.

    2012-04-01

    Mycorrhizal fungi consume fixed C in ecosystems in exchange for soil resources. We used sensor and observation platforms belowground to quantify belowground dynamics in a California mixed-conifer ecosystem. We directly observed growth and mortality of mycorrhizal fungi in situ on a daily basis using an automated minirhizotron. We measured soil CO2, T and soil moisture at 5-min intervals into the soil profile. These data are coupled with sensors measuring eddy flux of water and CO2, sapflow for water fluxes and C fixation activity, and photographs for leaf phenology. We used DayCent modeling for net primary productivity (NPP) and measured NPP of rhizomorphs, and fungal hyphae. In an arbuscular mycorrhizal (AM) meadow, NPP was 141g/m2/y, with a productivity of fine root NPP of 76.5g C/m2/y, an estimated 10 percent of which is AM fungal C (7.7 g/m2/y). Extramatrical AM hyphal peak standing crop was 4.4g/m2, with a lifespan of 46 days, with active hyphae persisting for 240 days per year. The extramatrical AM fungal hyphal C was 22.9g/m2/y, for a total net allocation to AM fungi of 30.5 C/m2/y, or 22 percent of the estimated NPP. In the ectomycorrhizal (EM) forest, root standing crop (200g C/m2/y) and rhizomorph (2mg C/m2/y) was 33 percent of the NPP (600g C/m2/y). EM fungal hyphae standing crop was 18g/m2/y, with a 48day lifespan, persisting throughout the year, or 59 g C/m2/y. EM root tips and rhizomorph life spans were nearly a year. Assuming that EM fungi represent 40 percent of the fine root EM NPP (of 200g C/m2/y) or 80g C/m2/y, most of the rhizomorph (in the mineral soil) mass being EM (or 2mg C), and 57 percent of the soil fungal NPP or 80 g C/m2/y, then the EM NPP is 139 C/m2/y, or 23 percent of the estimated NPP (600g C/m2/y). As an independent check on the allocation of C, we applied the Hobbie and Hobbie isotopic fractionation d15N model to C allocation. Using d15N of Chantarellus sp. (10.6) and Rhizopogon sp. (9.1), with a leaf d15N of -4.9, we estimated

  8. Potential impact of (CET) carbon emissions trading on China's power sector: A perspective from different allowance allocation options

    International Nuclear Information System (INIS)

    Cong, Rong-Gang; Wei, Yi-Ming

    2010-01-01

    In Copenhagen climate conference China government promised that China would cut down carbon intensity 40-45% from 2005 by 2020. CET (carbon emissions trading) is an effective tool to reduce emissions. But because CET is not fully implemented in China up to now, how to design it and its potential impact are unknown to us. This paper studies the potential impact of introduction of CET on China's power sector and discusses the impact of different allocation options of allowances. Agent-based modeling is one appealing new methodology that has the potential to overcome some shortcomings of traditional methods. We establish an agent-based model, CETICEM (CET Introduced China Electricity Market), of introduction of CET to China. In CETICEM, six types of agents and two markets are modeled. We find that: (1) CET internalizes environment cost; increases the average electricity price by 12%; and transfers carbon price volatility to the electricity market, increasing electricity price volatility by 4%. (2) CET influences the relative cost of different power generation technologies through the carbon price, significantly increasing the proportion of environmentally friendly technologies; expensive solar power generation in particular develops significantly, with final proportion increasing by 14%. (3) Emission-based allocation brings about both higher electricity and carbon prices than by output-based allocation which encourages producers to be environmentally friendly. Therefore, output-based allocation would be more conducive to reducing emissions in the Chinese power sector. (author)

  9. 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

  10. Age, allocation and availability of nonstructural carbon in mature red maple trees.

    Science.gov (United States)

    Carbone, Mariah S; Czimczik, Claudia I; Keenan, Trevor F; Murakami, Paula F; Pederson, Neil; Schaberg, Paul G; Xu, Xiaomei; Richardson, Andrew D

    2013-12-01

    The allocation of nonstructural carbon (NSC) to growth, metabolism and storage remains poorly understood, but is critical for the prediction of stress tolerance and mortality. We used the radiocarbon ((14) C) 'bomb spike' as a tracer of substrate and age of carbon in stemwood NSC, CO2 emitted by stems, tree ring cellulose and stump sprouts regenerated following harvesting in mature red maple trees. We addressed the following questions: which factors influence the age of stemwood NSC?; to what extent is stored vs new NSC used for metabolism and growth?; and, is older, stored NSC available for use? The mean age of extracted stemwood NSC was 10 yr. More vigorous trees had both larger and younger stemwood NSC pools. NSC used to support metabolism (stem CO2 ) was 1-2 yr old in spring before leaves emerged, but reflected current-year photosynthetic products in late summer. The tree ring cellulose (14) C age was 0.9 yr older than direct ring counts. Stump sprouts were formed from NSC up to 17 yr old. Thus, younger NSC is preferentially used for growth and day-to-day metabolic demands. More recently stored NSC contributes to annual ring growth and metabolism in the dormant season, yet decade-old and older NSC is accessible for regrowth. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  11. Herbivory alters plant carbon assimilation, patterns of biomass allocation and nitrogen use efficiency

    Science.gov (United States)

    Peschiutta, María Laura; Scholz, Fabián Gustavo; Goldstein, Guillermo; Bucci, Sandra Janet

    2018-01-01

    Herbivory can trigger physiological processes resulting in leaf and whole plant functional changes. The effects of chronic infestation by an insect on leaf traits related to carbon and nitrogen economy in three Prunus avium cultivars were assessed. Leaves from non-infested trees (control) and damaged leaves from infested trees were selected. The insect larvae produce skeletonization of the leaves leaving relatively intact the vein network of the eaten leaves and the abaxial epidermal tissue. At the leaf level, nitrogen content per mass (Nmass) and per area (Narea), net photosynthesis per mass (Amass) and per area (Aarea), photosynthetic nitrogen-use efficiency (PNUE), leaf mass per area (LMA) and total leaf phenols content were measured in the three cultivars. All cultivars responded to herbivory in a similar fashion. The Nmass, Amass, and PNUE decreased, while LMA and total content of phenols increased in partially damaged leaves. Increases in herbivore pressure resulted in lower leaf size and total leaf area per plant across cultivars. Despite this, stem cumulative growth tended to increase in infected plants suggesting a change in the patterns of biomass allocation and in resources sequestration elicited by herbivory. A larger N investment in defenses instead of photosynthetic structures may explain the lower PNUE and Amass observed in damaged leaves. Some physiological changes due to herbivory partially compensate for the cost of leaf removal buffering the carbon economy at the whole plant level.

  12. Applying life-cycle assessment to low carbon fuel standards-How allocation choices influence carbon intensity for renewable transportation fuels

    International Nuclear Information System (INIS)

    Kaufman, Andrew S.; Meier, Paul J.; Sinistore, Julie C.; Reinemann, Douglas J.

    2010-01-01

    The Energy Independence and Security Act (EISA) of 2007 requires life-cycle assessment (LCA) for quantifying greenhouse gas emissions (GHGs) from expanded U.S. biofuel production. To qualify under the Renewable Fuel Standard, cellulosic ethanol and new corn ethanol must demonstrate 60% and 20% lower emissions than petroleum fuels, respectively. A combined corn-grain and corn-stover ethanol system could potentially satisfy a major portion of renewable fuel production goals. This work examines multiple LCA allocation procedures for a hypothetical system producing ethanol from both corn grain and corn stover. Allocation choice is known to strongly influence GHG emission results for corn-ethanol. Stover-derived ethanol production further complicates allocation practices because additional products result from the same corn production system. This study measures the carbon intensity of ethanol fuels against EISA limits using multiple allocation approaches. Allocation decisions are shown to be paramount. Under varying approaches, carbon intensity for corn ethanol was 36-79% that of gasoline, while carbon intensity for stover-derived ethanol was -10% to 44% that of gasoline. Producing corn-stover ethanol dramatically reduced carbon intensity for corn-grain ethanol, because substantially more ethanol is produced with only minor increases in emissions. Regulatory considerations for applying LCA are discussed.

  13. Deep nitrogen acquisition in warming permafrost soils: Contributions of belowground plant traits and fungal symbioses in the permafrost carbon feedback to climate

    Science.gov (United States)

    Hartnett, H. E.; Palta, M. M.; Grimm, N. B.; Ruhi, A.; van Shaijik, M.

    2016-12-01

    Tempe Town Lake (TTL) is a hydrologically-regulated reservoir in Tempe, Arizona. The lake has high primary production and receives dissolved organic carbon (DOC) from rainfall, storm flow, and upstream river discharge. We applied an ARIMA time-series model to a three-year period for which we have high-frequency chemistry, meteorology, and streamflow data and analyzed external (rainfall, stream flow) and internal (dissolved O2) drivers of DOC content and composition. DOC composition was represented by fluorescence-based indices (fluorescence index, humification index, freshness) related to DOC source (microbially- vs. terrestrially-derived) and reactivity DOC. Patterns in DOC concentration and composition suggest carbon cycling in the lake responds to both meteorological events and to anthropogenic activity. The fluorescence-derived DOC composition is consistent with seasonally-distinct inputs of algal- and terrestrially-derived carbon. For example, Tempe Town Lake is supersaturated in O2 over 70% of the time, suggesting the system is autotrophic and primary productivity (i.e., O2 saturation state) was the strongest driver of DOC concentration. In contrast, external drivers (rainfall pattern, streamflow) were the strongest determinants of DOC composition. Biological processes (e.g., algal growth) generate carbon in the lake during spring and summer, and high Fluorescence Index and Freshness values at this time are indicative of algal-derived material; these parameters generally decrease with rain or flow suggesting algal-derived carbon is diluted by external water inputs. During dry periods, carbon builds up on the land surface and subsequent rainfall events deliver terrestrial carbon to the lake. Further evidence that rain and streamflow deliver land-derived material are increases in the Humification Index (an indicator of terrestrial material) following rain/flow events. Our results indicate that Tempe Town Lake generates autochthonous carbon and has the capacity

  14. Optimal Plant Carbon Allocation Implies a Biological Control on Nitrogen Availability

    Science.gov (United States)

    Prentice, I. C.; Stocker, B. D.

    2015-12-01

    The degree to which nitrogen availability limits the terrestrial C sink under rising CO2 is a key uncertainty in carbon cycle and climate change projections. Results from ecosystem manipulation studies and meta-analyses suggest that plant C allocation to roots adjusts dynamically under varying degrees of nitrogen availability and other soil fertility parameters. In addition, the ratio of biomass production to GPP appears to decline under nutrient scarcity. This reflects increasing plant C exudation into the soil (Cex) with decreasing nutrient availability. Cex is consumed by an array of soil organisms and may imply an improvement of nutrient availability to the plant. Thus, N availability is under biological control, but incurs a C cost. In spite of clear observational support, this concept is left unaccounted for in Earth system models. We develop a model for the coupled cycles of C and N in terrestrial ecosystems to explore optimal plant C allocation under rising CO2 and its implications for the ecosystem C balance. The model follows a balanced growth approach, accounting for the trade-offs between leaf versus root growth and Cex in balancing C fixation and N uptake. We assume that Cex is proportional to root mass, and that the ratio of N uptake (Nup) to Cex is proportional to inorganic N concentration in the soil solution. We further assume that Cex is consumed by N2-fixing processes if the ratio of Nup:Cex falls below the inverse of the C cost of N2-fixation. Our analysis thereby accounts for the feedbacks between ecosystem C and N cycling and stoichiometry. We address the question of how the plant C economy will adjust under rising atmospheric CO2 and what this implies for the ecosystem C balance and the degree of N limitation.

  15. Detecting carbon uptake and cellular allocation by individual algae in multispecies assemblages: Tracking carbon into single algal cells

    Energy Technology Data Exchange (ETDEWEB)

    Murdock, Justin N. [USDA Agricultural Research Service, National Sedimentation Laboratory, Oxford Mississippi; Department of Biology, Tennessee Technological University, Cookeville Tennessee

    2015-11-03

    Algal species vary in carbon (C) need and uptake rates. Understanding differences in C uptake and cellular allocation among species from natural communities will bring new insight into many ecosystem process questions including how species changes will alter energy availability and C sequestration in aquatic ecosystems. A major limitation of current methods that measure algal C incorporation is the inability to separate the response of individual species from mixed-species assemblages. I used Fourier-transform infrared microspectroscopy to qualitatively measure inorganic 13C isotope incorporation into individual algal cells in single species, two species, and natural phytoplankton assemblages. Lateral shifts in spectral peaks from 13C treatments were observed in all species. Comparison of peaks associated with carbohydrates, proteins, and lipids allowed for the detection of which individuals took in C, and which macromolecules the C was used to make. For example, shifts in Spirogyra spectral peaks showed substantial C incorporation in carbohydrates. Further, shifts in peaks at 1160 cm-1, 1108 cm-1, 1080 cm-1, 1048 cm-1, and 1030 cm-1 suggested C was being allocated into cellulose. The natural phytoplankton assemblage demonstrated how C could be tracked into co-occurring species. A diatom had large shifts in protein and carbohydrate peaks, while a green alga and euglenoid had only a few shifts in protein related peaks. Fourier-transform infrared microspectroscopy is an established, label free method for measuring the chemical composition of algal cells. However, adding a label such as 13C isotope can greatly expand the technique's capabilities by qualitatively tracking C movement between inorganic and organic states within single cells.

  16. Long-term development of above- and below-ground carbon stocks following land-use change in subalpine ecosystems of the Swiss National Park

    Science.gov (United States)

    Anita C. Risch; Martin F. Jurgensen; Deborah S. Page-Dumroese; Otto Wildi; Martin Schultz

    2008-01-01

    Vegetation changes following agricultural land abandonment at high elevation - which is frequent in Europe - could have a major impact on carbon (C) sequestration. However, most information on the effects of vegetation changes on ecosystem C stocks originates from low-elevation studies on reforestation or early successional forests, and little is known about how these...

  17. Photoperiodic effects on short-pulse 14C assimilation and overall carbon and nitrogen allocation patterns in contrasting quinoa cultivars

    DEFF Research Database (Denmark)

    Bendevis, Mira Arpe; Sun, Yujie; Rosenqvist, Eva

    2014-01-01

    ' and photoperiod neutral cv. 'Titicaca' were studied under short (10h) and long (17.5h) days, with respect to C and N distribution as well as partitioning of newly assimilated C to plant organs. An extended photoperiod resulted in 14C decreasingly being allocated to stem growth and lower leaves in 'Titicaca...... with an immediate increase in carbon allocation to upper leaves, and over time to the reproductive structures, resulting in a more than 50% increase in final yield. Collectively the results indicate that even though the photoperiod sensitive cultivar flowered under long photoperiod it did not develop seeds, whereas...

  18. Lipid-rich and protein-poor carbon allocation patterns of phytoplankton in the northern Chukchi Sea, 2011

    Science.gov (United States)

    Yun, Mi Sun; Joo, Hui Tae; Park, Jung Woo; Kang, Jae Joong; Kang, Sung-Ho; Lee, Sang H.

    2018-04-01

    The carbon allocations of phytoplankton into different photosynthetic end products (lipids, LMWM, polysaccharides, and proteins) were determined to understand physiological conditions of phytoplankton in the northern Chukchi Sea during the Korean Arctic expedition, 2011, using the 13C isotope tracer technique. The carbon allocation rates of lipids, LMWM, polysaccharides, and proteins were 0.00009-0.00062 h-1, 0.00001-0.00049 h-1, 0.00001-0.00025 h-1, and 0.00001-0.00062 h-1 within the euphotic depths from surface to 1% light depths during our cruise period, respectively. Significant relationships between protein production rates and chlorophyll a concentrations (large and total) were found in this study. Moreover, we found a significant negative relationship between lipid production rates and ammonium concentrations. These relationships match well with the previous results for environmental/physiological conditions for phytoplankton growth. Overall, phytoplankton allocated more photosynthetic carbon into lipids (42.5 ± 17.7%) whereas relatively lower to proteins (20.4 ± 15.5%) in this study. The lipid-rich and protein-poor allocation patterns in this study suggest that phytoplankton in the northern Chukchi Sea were in a stationary growth phase under nutrient deficient condition based on biological and environmental conditions observed during our study period. Based on comparison with the previous studies in the northern Bering Sea and southern Chukchi Sea, we found that the photosynthetic carbon allocation patterns depending on physiological status of phytoplankton under the different growth and/or nutrient conditions could be largely vary at different regions in the Arctic Ocean. More intensive research on the physiological status of phytoplankton is further required to determine how phytoplankton response to the changing environmental conditions and consequently how they impact on higher trophic levels in marine ecosystems in the Arctic Ocean.

  19. Carbon allocation to growth and storage in two evergreen species of contrasting successional status.

    Science.gov (United States)

    Piper, Frida I; Sepúlveda, Paulina; Bustos-Salazar, Angela; Zúñiga-Feest, Alejandra

    2017-05-01

    A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-growing tree species in the world ( Eucalyptus globulus ) and a shade-tolerant, slow-growing species ( Luma apiculata ). Seedlings were subjected to one out of four combinations of light (high vs. low) and initial defoliation (90% defoliated vs. nondefoliated) for four months. Growth, C storage concentration in different organs, leaf shedding, and lateral shoot formation were measured at the end of the experiment. Eucalyptus globulus grew faster than L. apiculata in high light, but not in low light. Both species had lower C storage concentration in low than in high light, but similar C storage concentrations in each light condition. Defoliation had no effect on C storage, except in the case of the old leaves of both species, which showed lower C storage levels in response to defoliation. Across treatments, leaf shedding was 96% higher in E. globulus than in L. apiculata while, in contrast, lateral shoot formation was 87% higher in L. apiculata . In low light, E. globulus prioritized C storage instead of growth, whereas L. apiculata prioritized growth and lateral branching. Our results suggest that shade tolerance depends on efficient light capture rather than C conservation traits. © 2017 Botanical Society of America.

  20. Nutrient demand and fungal access to resources control the carbon allocation to the symbiotic partners in tripartite interactions of Medicago truncatula.

    Science.gov (United States)

    Kafle, Arjun; Garcia, Kevin; Wang, Xiurong; Pfeffer, Philip E; Strahan, Gary D; Bücking, Heike

    2018-06-02

    Legumes form tripartite interactions with arbuscular mycorrhizal (AM) fungi and rhizobia, and both root symbionts exchange nutrients against carbon from their host. The carbon costs of these interactions are substantial, but our current understanding of how the host controls its carbon allocation to individual root symbionts is limited. We examined nutrient uptake and carbon allocation in tripartite interactions of Medicago truncatula under different nutrient supply conditions, and when the fungal partner had access to nitrogen, and followed the gene expression of several plant transporters of the SUT and SWEET family. Tripartite interactions led to synergistic growth responses and stimulated the phosphate and nitrogen uptake of the plant. Plant nutrient demand but also fungal access to nutrients played an important role for the carbon transport to different root symbionts, and the plant allocated more carbon to rhizobia under nitrogen demand, but more carbon to the fungal partner when nitrogen was available. These changes in carbon allocation were consistent with changes in the SUT and SWEET expression. Our study provides important insights into how the host plant controls its carbon allocation under different nutrient supply conditions and changes its carbon allocation to different root symbionts to maximize its symbiotic benefits. This article is protected by copyright. All rights reserved.

  1. Forecasting the Allocative Efficiency of Carbon Emission Allowance Financial Assets in China at the Provincial Level in 2020

    Directory of Open Access Journals (Sweden)

    Shihong Zeng

    2016-05-01

    Full Text Available As the result of climate change and deteriorating global environmental quality, nations are under pressure to reduce their emissions of greenhouse gases per unit of GDP. China has announced that it is aiming not only to reduce carbon emission per unit of GDP, but also to consume increased amounts of non-fossil energy. The carbon emission allowance is a new type of financial asset in each Chinese province and city that also affects individual firms. This paper attempts to examine the allocative efficiency of carbon emission reduction and non-fossil energy consumption by employing a zero sum gains data envelopment analysis (ZSG-DEA model, given the premise of fixed CO2 emissions as well as non-fossil energy consumption. In making its forecasts, the paper optimizes allocative efficiency in 2020 using 2010 economic and carbon emission data from 30 provinces and cities across China as its baseline. An efficient allocation scheme is achieved for all the provinces and cities using the ZSG-DEA model through five iterative calculations.

  2. Carbon Dynamics in Heathlands in Response to a Changing Climate

    DEFF Research Database (Denmark)

    Nielsen, Pia Lund

    Climate is changing, and more adverse changes are expected in the future. Changes, caused by continuously rising atmospheric concentrations of greenhouse gasses as CO2, will affect ecosystem processes and functions in the future and hence the cycling of carbon. The vaste amount of studies have...... layers showed much slower decomposition than fine root from top layer. Higher roots biomass and allocation of carbon deeper down in the soil profile in response to elevated CO2 combined with the slower decomposition of deep roots could affect future carbon cycling, but soil carbon sequestration depends...... focused on effects of climate change on aboveground biomass, less have been conducted on belowground biomass, and the thesis is one of few studies comprising both above- and belowground biomass and take interactions of climate change factors into account. To follow the fate of carbon in the ecosystem we...

  3. Running Title: C and N Allocation in Pine; FINAL

    International Nuclear Information System (INIS)

    Ball, J. Timothy

    1996-01-01

    A long standing challenge has been understanding how plants and ecosystems respond to shifts in the balance of resource availabilities. The continuing rise in atmospheric CO(sub 2) will induce changes in the availability and use of several terrestrial ecosystem resources. We report on the acquisition and allocation of carbon and nitrogen in Pinus ponderosa Laws. seedlings grown at three levels of atmospheric carbon dioxide (370, 525, and 700(micro)mol mol(sup -1)) and three levels of soil nitrogen supply in a controlled environment experiment. Nitrogen was applied (0, 100, and 200(micro)g N g soil(sup -1)) at planting and again at week 26 of a 58-week, 4-harvest experiment. At the final harvest, plants grown with variety low available soil nitrogen showed no significant response to atmospheric CO(sub 2). Plants at higher N levels responded positively to CO(sub 2) with the highest biomass at the middle CO(sub 2) level. Plants growing at the lowest N levels immediately allocated a relatively large portion of their nitrogen and biomass to roots. Plants growing at near present ambient CO(sub 2) levels allocated relatively little material to roots when N was abundant but moved both carbon and nitrogen below-ground when N was withheld. Plants growing at higher CO(sub 2) levels, allocated more C and N to roots even when N was abundant, and made only small shifts in allocation patterns when N was no longer supplied. In general, allocation of C and N to roots tended to increase when N supply was restricted and also with increasing atmospheric CO(sub 2) level. These allocation responses were consistent with patterns suggesting a functional balance in the acquisition of above-ground versus below-ground resources. In particular, variation in whole tree average nitrogen concentration can explain 68% of the variation ratio of root biomass to shoot biomass across the harvests. The capability to respond to temporal variation in nutrient conditions, the dynamics of nutrient uptake

  4. Dynamics of oxygen and carbon dioxide in rhizospheres of Lobelia dortmanna - a planar optode study of belowground gas exchange between plants and sediment.

    Science.gov (United States)

    Lenzewski, Nikola; Mueller, Peter; Meier, Robert Johannes; Liebsch, Gregor; Jensen, Kai; Koop-Jakobsen, Ketil

    2018-04-01

    Root-mediated CO 2 uptake, O 2 release and their effects on O 2 and CO 2 dynamics in the rhizosphere of Lobelia dortmanna were investigated. Novel planar optode technology, imaging CO 2 and O 2 distribution around single roots, provided insights into the spatiotemporal patterns of gas exchange between roots, sediment and microbial community. In light, O 2 release and CO 2 uptake were pronounced, resulting in a distinct oxygenated zone (radius: c. 3 mm) and a CO 2 -depleted zone (radius: c. 2 mm) around roots. Simultaneously, however, microbial CO 2 production was stimulated within a larger zone around the roots (radius: c. 10 mm). This gave rise to a distinct pattern with a CO 2 minimum at the root surface and a CO 2 maximum c. 2 mm away from the root. In darkness, CO 2 uptake ceased, and the CO 2 -depleted zone disappeared within 2 h. By contrast, the oxygenated root zone remained even after 8 h, but diminished markedly over time. A tight coupling between photosynthetic processes and the spatiotemporal dynamics of O 2 and CO 2 in the rhizosphere of Lobelia was demonstrated, and we suggest that O 2 -induced stimulation of the microbial community in the sediment increases the supply of inorganic carbon for photosynthesis by building up a CO 2 reservoir in the rhizosphere. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  5. Potential impact of (CET) carbon emissions trading on China’s power sector: A perspective from different allowance allocation options

    OpenAIRE

    Cong, Rong-Gang; Wei, Yi-Ming

    2010-01-01

    In Copenhagen climate conference China government promised that China would cut down carbon intensity 40e45% from 2005 by 2020. CET (carbon emissions trading) is an effective tool to reduce emissions. But because CET is not fully implemented in China up to now, how to design it and its potential impact are unknown to us. This paper studies the potential impact of introduction of CET on China’s power sector and discusses the impact of different allocation options of allowances. Agent-based mod...

  6. Plant neighbour identity matters to belowground interactions under controlled conditions.

    Science.gov (United States)

    Armas, Cristina; Pugnaire, Francisco Ignacio

    2011-01-01

    Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

  7. Spatially Resolved Carbon Isotope and Elemental Analyses of the Root-Rhizosphere-Soil System to Understand Below-ground Nutrient Interactions

    Science.gov (United States)

    Denis, E. H.; Ilhardt, P.; Tucker, A. E.; Huggett, N. L.; Rosnow, J. J.; Krogstad, E. J.; Moran, J.

    2017-12-01

    The intimate relationships between plant roots, rhizosphere, and soil are fostered by the release of organic compounds from the plant (through various forms of rhizodeposition) into soil and the simultaneous harvesting and delivery of inorganic nutrients from the soil to the plant. This project's main goal is to better understand the spatial controls on bi-directional nutrient exchange through the rhizosphere and how they impact overall plant health and productivity. Here, we present methods being developed to 1) spatially track the release and migration of plant-derived organics into the rhizosphere and soil and 2) map the local inorganic geochemical microenvironments within and surrounding the rhizosphere. Our studies focused on switchgrass microcosms containing soil from field plots at the Kellogg Biological Station (Hickory Corners, Michigan), which have been cropped with switchgrass for nearly a decade. We used a 13CO2 tracer to label our samples for both one and two diel cycles and tracked subsequent movement of labeled organic carbon using spatially specific δ13C analysis (with 50 µm resolution). The laser ablation-isotope ratio mass spectrometry (LA-IRMS) approach allowed us to map the extent of 13C-label migration into roots, rhizosphere, and surrounding soil. Preliminary results show the expected decrease of organic exudates with distance from a root and that finer roots (<0.1 mm) incorporated more 13C-label than thicker roots, which likely correlates to specific root growth rates. We are adapting both laser induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to spatially map inorganic nutrient content in the exact same samples used for LA-IRMS analysis. Both of these methods provide rapid surface mapping of a wide range of elements (with high dynamic range) at 150 μm spatial resolution. Preliminary results show that, based on elemental content, we can distinguish between roots, rhizosphere

  8. Light Competition and Carbon Partitioning-Allocation in an improved Forest Ecosystem Model

    Science.gov (United States)

    Collalti, Alessio; Santini, Monia; Valentini Valentini, Riccardo

    2010-05-01

    . Hence, the presence of a cohort in a storey determines the amount of light received for the photosynthetic processes. The population density (numbers of trees per cell) represents a good competition index for determining the tree crown structure and tree crown dimension within a forest population. The tree crown tend to branch out horizontally to intercept as much light as possible. The model assess the structure of the tree crown both vertically and horizontally on the base of the population density and it up-scales the result to the whole stand. The canopy depth and the percentage of horizontal coverage determines moreover a crowding competition index that lead to a specific biomass partitioning-allocation ratio among the different tree components (foliage, roots and stem) and especially for the stem affecting Height-Diameter (at breast height) ratio. In this model, Height-Diameter ratio is used as an alternative competition index in determining the vigour and the strength of competition on free growth status of trees. The forest dominant vegetative cover affects moreover the presence of a dominated layer, it influences its yield and its Carbon stocking capacity and hence it influences the forest ecosystem CO2 carbon balance. From this model it is possible to simulate the impact of Climate Change on forests, the feedback of one or more dominated layers in terms of CO2 uptake in a forest stand and the effects of forest management activities for the next years.

  9. Can decision rules simulate carbon allocation for years with contrasting and extreme weather conditions? A case study for three temperate beech forests

    DEFF Research Database (Denmark)

    Campioli, Matteo; Verbeeck, Hans; Van den Bossche, Joris

    2013-01-01

    The allocation of carbohydrates to different tree processes and organs is crucial to understand the overall carbon (C) cycling rate in forest ecosystems. Decision rules (DR) (e.g. functional balances and source-sink relationships) are widely used to model C allocation in forests. However, standard...... allocation and wood growth at beech stands with contrasting climate and standing stock. However, the allocation model required high quality GPP input and errors (even modest) in GPP resulted in large errors in the growth of the tree organs lowest in the modelled sink hierarchy (woody organs). The ability...

  10. Free allocations in EU ETS Phase 3: The impact of emissions performance benchmarking for carbon-intensive industry - Working Paper No. 2013-14

    International Nuclear Information System (INIS)

    Lecourt, S.; Palliere, C.; Sartor, O.

    2013-02-01

    From Phase 3 (2013-20) of the European Union Emissions Trading Scheme, carbon-intensive industrial emitters will receive free allocations based on harmonised, EU-wide benchmarks. This paper analyses the impacts of these new rules on allocations to key energy-intensive sectors across Europe. It explores an original dataset that combines recent data from the National Implementing Measures of 20 EU Member States with the Community Independent Transaction Log and other EU documents. The analysis reveals that free allocations to benchmarked sectors will be reduced significantly compared to Phase 2 (2008-12). This reduction should both increase public revenues from carbon auctions and has the potential to enhance the economic efficiency of the carbon market. The analysis also shows that changes in allocation vary mostly across installations within countries, raising the possibility that the carbon-cost competitiveness impacts may be more intense within rather than across countries. Lastly, the analysis finds evidence that the new benchmarking rules will, as intended, reward installations with better emissions performance and will improve harmonisation of free allocations in the EU ETS by reducing differences in allocation levels across countries with similar carbon intensities of production. (authors)

  11. The impact of China's carbon allowance allocation rules on the product prices and emission reduction behaviors of ETS-covered enterprises

    International Nuclear Information System (INIS)

    Zhang, Yue-Jun; Wang, Ao-Dong; Tan, Weiping

    2015-01-01

    It is an important task for China to allocate carbon emission allowance to realize its carbon reduction target and establish carbon trading market. China has designed several allocation rules within seven pilot regions. What influence those rules may cause is closely related with the enthusiasm of emission trading scheme (ETS) covered enterprises' participation in carbon market, and more importantly, with the mechanism design and sustainable development of carbon market. For this purpose, the multi-stage profit model is developed to analyze the ETS-covered enterprises' product prices and emission reduction behaviors under different allocation rules. The results show that, first, under the rules of grandfathering, self-declaration and auctioning, when deciding the optimal product price and optimal carbon emission reduction, those enterprises may focus on maximizing current stage profit; however, under the rule of benchmarking, those enterprises may care more about the impact of current decisions on the profit in next stage. Second, the optimal product price policy is positively correlated with the price of the same kind products, consumers' low-carbon awareness and government subsidy. Finally, along with the increase of carbon price, consumers' low-carbon awareness and government subsidy and the decrease of carbon emission cap, those enterprises tend to reduce carbon emissions. - Highlights: • Analyze the impact of carbon allowance allocation rules on ETS-covered enterprises. • For grandfather, self-declaration and auction, they may maximize current profits. • For benchmark, they care the effect of current decisions on the coming profits. • The optimal product price positively relates to low-carbon awareness and subsidy. • Carbon price, low-carbon awareness and subsidy rise leads their emission reduction.

  12. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Science.gov (United States)

    Elhakeem, Ali; Markovic, Dimitrije; Broberg, Anders; Anten, Niels P R; Ninkovic, Velemir

    2018-01-01

    Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  13. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Directory of Open Access Journals (Sweden)

    Ali Elhakeem

    Full Text Available Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution or untouched plants (C_solution. The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  14. Allocation pattern and accumulation potential of carbon stock in natural spruce forests in northwest China

    Directory of Open Access Journals (Sweden)

    Jun-Wei Yue

    2018-05-01

    Full Text Available Background The spruce forests are dominant communities in northwest China, and play a key role in national carbon budgets. However, the patterns of carbon stock distribution and accumulation potential across stand ages are poorly documented. Methods We investigated the carbon stocks in biomass and soil in the natural spruce forests in the region by surveys on 39 plots. Biomass of tree components were estimated using allometric equations previously established based on tree height and diameter at breast height, while biomass in understory (shrub and herb and forest floor were determined by total harvesting method. Fine root biomass was estimated by soil coring technique. Carbon stocks in various biomass components and soil (0–100 cm were estimated by analyzing the carbon content of each component. Results The results showed that carbon stock in these forest ecosystems can be as high as 510.1 t ha−1, with an average of 449.4 t ha−1. Carbon stock ranged from 28.1 to 93.9 t ha−1 and from 0.6 to 8.7 t ha−1 with stand ages in trees and deadwoods, respectively. The proportion of shrubs, herbs, fine roots, litter and deadwoods ranged from 0.1% to 1% of the total ecosystem carbon, and was age-independent. Fine roots and deadwood which contribute to about 2% of the biomass carbon should be attached considerable weight in the investigation of natural forests. Soil carbon stock did not show a changing trend with stand age, ranging from 254.2 to 420.0 t ha−1 with an average of 358.7 t ha−1. The average value of carbon sequestration potential for these forests was estimated as 29.4 t ha−1, with the lower aged ones being the dominant contributor. The maximum carbon sequestration rate was 2.47 t ha−1 year−1 appearing in the growth stage of 37–56 years. Conclusion The carbon stock in biomass was the major contributor to the increment of carbon stock in ecosystems. Stand age is not a good predictor of soil carbon stocks and accurate

  15. Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5 on carbon fluxes, pools, and turnover in temperate forests

    Directory of Open Access Journals (Sweden)

    F. Montané

    2017-09-01

    Full Text Available How carbon (C is allocated to different plant tissues (leaves, stem, and roots determines how long C remains in plant biomass and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and leaf area index (LAI measurements to compare C fluxes, pools, and LAI data with those predicted by a land surface model (LSM, the Community Land Model (CLM4.5. We ran CLM4.5 for nine temperate (including evergreen and deciduous forests in North America between 1980 and 2013 using four different C allocation schemes: i. dynamic C allocation scheme (named "D-CLM4.5" with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual net primary production (NPP; ii. an alternative dynamic C allocation scheme (named "D-Litton", where, similar to (i, C allocation is a dynamic function of annual NPP, but unlike (i includes two dynamic allometric parameters involving allocation to leaves, stem, and coarse roots; iii.–iv. a fixed C allocation scheme with two variants, one representative of observations in evergreen (named "F-Evergreen" and the other of observations in deciduous forests (named "F-Deciduous". D-CLM4.5 generally overestimated gross primary production (GPP and ecosystem respiration, and underestimated net ecosystem exchange (NEE. In D-CLM4.5, initial aboveground biomass in 1980 was largely overestimated (between 10 527 and 12 897 g C m−2 for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011 was highly underestimated (between 1222 and 7557 g C m−2 for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM4.5 overestimated LAI in both evergreen and deciduous sites because the leaf C–LAI relationship in the model did not match the

  16. Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5) on carbon fluxes, pools, and turnover in temperate forests

    Science.gov (United States)

    Montané, Francesc; Fox, Andrew M.; Arellano, Avelino F.; MacBean, Natasha; Alexander, M. Ross; Dye, Alex; Bishop, Daniel A.; Trouet, Valerie; Babst, Flurin; Hessl, Amy E.; Pederson, Neil; Blanken, Peter D.; Bohrer, Gil; Gough, Christopher M.; Litvak, Marcy E.; Novick, Kimberly A.; Phillips, Richard P.; Wood, Jeffrey D.; Moore, David J. P.

    2017-09-01

    How carbon (C) is allocated to different plant tissues (leaves, stem, and roots) determines how long C remains in plant biomass and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and leaf area index (LAI) measurements) to compare C fluxes, pools, and LAI data with those predicted by a land surface model (LSM), the Community Land Model (CLM4.5). We ran CLM4.5 for nine temperate (including evergreen and deciduous) forests in North America between 1980 and 2013 using four different C allocation schemes: i. dynamic C allocation scheme (named "D-CLM4.5") with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual net primary production (NPP); ii. an alternative dynamic C allocation scheme (named "D-Litton"), where, similar to (i), C allocation is a dynamic function of annual NPP, but unlike (i) includes two dynamic allometric parameters involving allocation to leaves, stem, and coarse roots; iii.-iv. a fixed C allocation scheme with two variants, one representative of observations in evergreen (named "F-Evergreen") and the other of observations in deciduous forests (named "F-Deciduous"). D-CLM4.5 generally overestimated gross primary production (GPP) and ecosystem respiration, and underestimated net ecosystem exchange (NEE). In D-CLM4.5, initial aboveground biomass in 1980 was largely overestimated (between 10 527 and 12 897 g C m-2) for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011) was highly underestimated (between 1222 and 7557 g C m-2) for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM4.5 overestimated LAI in both evergreen and deciduous sites because the leaf C-LAI relationship in the model did not match the observed leaf C

  17. Tendances Carbone no. 99. EU ETS and competitiveness: the tricky equation of free allocation through to 2030

    International Nuclear Information System (INIS)

    Jalard, Matthieu; Alberola, Emilie

    2015-02-01

    Among the publications of CDC Climat Research, 'Tendances Carbone' bulletin specifically studies the developments of the European market for CO 2 allowances. Beside some statistical figures about energy production/consumption and carbon markets, this issue specifically addresses the following points: - EU ETS - MSR debate: on 21 January, the ITRE committee of the European Parliament voted and rejected amendments to the MSR reform, and therefore will not provide any opinion concerning the mechanism to the ENVI committee. - EU ETS - MSR timetable: the ENVI committee voted on 23 and 24 February 2015 about possible amendments to the MSR. - New Entrants Reserve (NER): 18.6 million allowances were allocated in 2013 and 2014, 51 million will be earmarked for the period 2015-2020

  18. Partitioning CO2 fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Eric A. [Woods Hole Research Center, Falmouth, MA (United States); Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Savage, Kathleen [Woods Hole Research Center, Falmouth, MA (United States); Finzi, Adrien [Boston Univ., MA (United States); Moorcroft, Paul [Harvard Univ., Cambridge, MA (United States); Wehr, Richard [Univ. of Arizona, Tucson, AZ (United States)

    2016-02-18

    1. Project Summary and Objectives This project combines automated in situ observations of the isotopologues of CO2 with root observations, novel experimental manipulations of belowground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. aboveground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: A. Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics ; B. Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated belowground using measurements of root growth and indices of belowground autotrophic vs. heterotrophic respiration (via trenched plots and isotope measurements); C. Testing whether plant allocation of carbon belowground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and D. Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2).

  19. An improved parameterization of the allocation of assimilated carbon to plant parts in vegetation dynamics for Noah-MP

    Science.gov (United States)

    Gim, Hyeon-Ju; Park, Seon Ki; Kang, Minseok; Thakuri, Bindu Malla; Kim, Joon; Ho, Chang-Hoi

    2017-08-01

    In the land surface models predicting vegetation growth and decay, representation of the seasonality of land surface energy and mass fluxes largely depends on how to describe the vegetation dynamics. In this study, we developed a new parameterization scheme to characterize allocation of the assimilated carbon to plant parts, including leaves and fine roots. The amount of carbon allocation in this scheme depends on the climatological net primary production (NPP) of the plants. The newly developed scheme is implemented in the augmented Noah land surface model with multiple parameterization options (Noah-MP) along with other biophysical processes related to variations in photosynthetic capacity. The scheme and the augmented biophysical processes are evaluated against tower measurements of vegetation from four forest sites in various regions—two for the deciduous broadleaf and two for the needleleaf evergreen forest. Results from the augmented Noah-MP showed good agreement with the observations and demonstrated improvements in representing the seasonality of leaf area index (LAI), gross primary production (GPP), ecosystem respiration (ER), and latent heat flux. In particular, significant improvements are found in simulating amplitudes and phase shift timing in the LAI seasonal cycle, and the amount of GPP and ER in the growing season. Furthermore, the augmented Noah-MP performed reasonably well in simulating the spatial distributions of LAI, GPP, and NPP in East Asia, consistent with the satellite observations.

  20. Carbon allocation and element composition in four Chlamydomonas mutants defective in genes related to the CO2 concentrating mechanism.

    Science.gov (United States)

    Memmola, Francesco; Mukherjee, Bratati; Moroney, James V; Giordano, Mario

    2014-09-01

    Four mutants of Chlamydomonas reinhardtii with defects in different components of the CO2 concentrating mechanism (CCM) or in Rubisco activase were grown autotrophically at high pCO2 and then transferred to low pCO2, in order to study the role of different components of the CCM on carbon allocation and elemental composition. To study carbon allocation, we measured the relative size of the main organic pools by Fourier Transform Infrared spectroscopy. Total reflection X-ray fluorescence was used to analyze the elemental composition of algal cells. Our data show that although the organic pools increased their size at high CO2 in all strains, their stoichiometry was highly homeostatic, i.e., the ratios between carbohydrates and proteins, lipid and proteins, and carbohydrates and lipids, did not change significantly. The only exception was the wild-type 137c, in which proteins decreased relative to carbohydrates and lipids, when the cells were transferred to low CO2. It is noticeable that the two wild types used in this study responded differently to the transition from high to low CO2. Malfunctions of the CCM influenced the concentration of several elements, somewhat altering cell elemental stoichiometry: especially the C/P and N/P ratios changed appreciably in almost all strains as a function of the growth CO2 concentration, except in 137c and the Rubisco activase mutant rca1. In strain cia3, defective in the lumenal carbonic anhydrase (CA), the cell quotas of P, S, Ca, Mn, Fe, and Zn were about 5-fold higher at low CO2 than at high CO2. A Principle Components Analysis showed that, mostly because of its elemental composition, cia3 behaved in a substantially different way from all other strains, at low CO2. The lumenal CA thus plays a crucial role, not only for the correct functioning of the CCM, but also for element utilization. Not surprisingly, growth at high CO2 attenuated differences among strains.

  1. Green supplier selection and order allocation in a low-carbon paper industry

    DEFF Research Database (Denmark)

    Govindan, Kannan; Sivakumar, R.

    2016-01-01

    is to engage the case company with their supplier networks to diminish the greenhouse gases (GHG) emissions and cost in their production process. It proposes a model to support the selection of the best green supplier and an allocation of order among the potential suppliers. The proposed model contains a two......-phase hybrid approach. The first phase presents the rating and selection of potential suppliers by considering economics (cost), operational factors (quality and delivery), and environmental criteria (recycle capability and GHG emission control) using Fuzzy Technique for Order of Preference by Similarity....... Finally, a conclusion and a suggested direction of future research are introduced....

  2. Auction design for the allocation of carbon emission allowances: uniform or discriminatory price?

    DEFF Research Database (Denmark)

    Cong, Ronggang; wei, yi-ming

    2010-01-01

    Only four states used auction in Phase Ⅰ (2005-2007) of the European Union Emission Trading System, of which four used a uniform-price sealed auction format. Here we discuss whether the auction should adopt a uniform-price or discriminatory-price format using an agent-based carbon allowances...... auction model established for the purpose. The main conclusions are as follows: (1) when carbon allowances are relatively scarce, the government should use a discriminatory-price auction; when carbon allowances are relatively abundant, the government should use a uniform-price auction. (2) Uncertainty......) The uniform-price auction is relatively insensitive to market structure. However, a monopoly market is more likely to develop under the discriminatory-price auction format. The results of the model have some policy implications for designing carbon market mechanisms in the future....

  3. Effect of regulated deficit irrigation on the morphology, physiology, carbon allocation and nonstructural carbohydrates of three Kentucky bluegrasses

    International Nuclear Information System (INIS)

    Liu, J. R.; Ma, L.; Liu, Y. K.; Liu, T. J.; Lu, J. N.; Wang, D. N.

    2015-01-01

    Regulated deficit irrigation (RDI) has been assessed in a wide number of field and fruit crops. However, few are the studies dealing with turfgrass. This study was conducted to investigate the morphology, physiology and carbon metabolic responses to regulated deficit irrigation for three Kentucky bluegrass (Poa pratensis L.) cultivars. Three Kentucky bluegrass cultivars were grown in PVC (polyvinyl chloride) tubes in a greenhouse and subjected to three soil water treatments in a growth chamber: 1) full irrigation; 2) drought stress, 21 days without water after full irrigation; and 3) drought recovery, stressed plants were re-watered for an additional 21 d. The present study indicated that drought resulted in a decline in turf quality (TQ), leaf relative water content (RWC), and photochemical efficiency (Fv/Fm) and an increase in electrolyte leakage (EL) for the cultivars. The turf quality, RWC, and Fv/Fm of the three Kentucky bluegrass cultivars increased with re-watering. The allocation of /sup 14/ C increased in the roots of these cultivars during the initial phase of drought stress, where a /sup 14/ C distribution shift from the roots to the stem and leaves appeared with further drought stress. Moreover, there was a significant accumulation of total nonstructural carbohydrates (TNC) in the leaves and stem. The TNC content in the leaves, stem, and roots did not completely return to the control levels following 21 d of re-watering, which was consistent with the recovery of TQ, RWC, Fv/Fm, and EL. In addition, during the re-watering treatment, the reduction in the TNC content may be due to increases in the demand or usage as a result of a rapid recovery in the growth and physiological activities as shown by increased TQ, RWC, and Fv/Fm and decreased EL. Our results suggested that the changes in the carbon allocation model and the accumulation and storage of TNC, as well as the changes in TQ, RWC, Fv/Fm, and EL, for the three cultivars are an adaptive reaction to

  4. The influence of season on carbon allocation to suberin and other stem components of cork oak saplings.

    Science.gov (United States)

    Aguado, Pedro L; Curt, M Dolores; Pereira, Helena; Fernández, Jesús

    2017-02-01

    The growth pattern of cork oak (Quercus suber L.), an important component of South Mediterranean woodlands, is seasonal. Seasonality has been found for shoot, radial and cork ring growth as well as for carbon (C) photoassimilation, nutrients remobilization and water relations, among other physiological aspects. However, little is known about the seasonality of C allocation to cork oak chemical compounds, including suberin, a major component of cork. In order to achieve this goal, an isotopic tracer experiment was conducted using 18-month-old cork oaks so that the fate of C photoassimilated in different seasons could be traced into biochemical (main organic) stem components. Two distinct patterns of C allocation, associated with the stages of active plant growth and dormancy, were identified and described. Evidence was provided that translocation of photoassimilated C to stems does not cease during the dormancy period and that suberin is the major C sink for the C assimilated throughout the whole active growth period, as compared with other stem components. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Analysis of trehalose-6-phosphate control over carbon allocation and growth in plants

    NARCIS (Netherlands)

    Aghdasi, M.

    2007-01-01

    Trehalose is the non-reducing alpha-alpha-1, 1-linked glucose disaccharide. The biosynthesic precursor of trehalose, trehalose-6-phosphate (T6P), is essential for plant development, growth, carbon utilization and alters photosynthetic capacity but its mode of action is not underestood. This thesis

  6. Ecosystem carbon density and allocation across a chronosequence of longleaf pine forests

    Science.gov (United States)

    Lisa J. Samuelson; Thomas A. Stokes; John R. Butnor; Kurt H. Johnsen; Carlos A. Gonzalez-Benecke; Timothy A. Martin; Wendell P. Cropper; Pete H. Anderson; Michael R. Ramirez; John C. Lewis

    2017-01-01

    Forests can partially offset greenhouse gas emissions and contribute to climate change mitigation, mainly through increases in live biomass. We quantified carbon (C) density in 20 managed longleaf pine (Pinus palustris Mill.) forests ranging in age from 5...

  7. Aspen SUCROSE TRANSPORTER3 Allocates Carbon into Wood Fibers1[C][W

    Science.gov (United States)

    Mahboubi, Amir; Ratke, Christine; Gorzsás, András; Kumar, Manoj; Mellerowicz, Ewa J.; Niittylä, Totte

    2013-01-01

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula × Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H+ symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after 13CO2 assimilation, the SUT3RNAi lines contained more 13C than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein:PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers. PMID:24170204

  8. Ecological linkages between aboveground and belowground biota

    NARCIS (Netherlands)

    Wardle, D.A.; Bardgett, R.D.; Klironomos, J.N.; Setälä, H.; Putten, van der W.H.; Wall, D.H.

    2004-01-01

    All terrestrial ecosystems consist of aboveground and belowground components that interact to influence community- and ecosystem-level processes and properties. Here we show how these components are closely interlinked at the community level, reinforced by a greater degree of specificity between

  9. Linking aboveground and belowground inducible plant resistance

    NARCIS (Netherlands)

    Bezemer, T.M.

    2009-01-01

    Induced resistance of plants against pests and diseases via plant defense responses is well documented and can occur aboveground, in the leaves, and belowground in the roots. A number of recent studies have shown that soil-borne pests can also induce plant resistance aboveground and vice versa.

  10. Below-ground process responses to elevated CO2 and temperature: a discussion of observations, measurement methods, and models

    Science.gov (United States)

    Elise Pendall; Scott Bridgham; Paul J. Hanson; Bruce Hungate; David W. Kicklighter; Dale W. Johnson; Beverly E. Law; Yiqi Luo; J. Patrick Megonigal; Maria Olsrud; Michael G. Ryan; Shiqiang Wan

    2004-01-01

    Rising atmospheric CO2 and temperatures are probably altering ecosystem carbon cycling, causing both positive and negative feedbacks to climate. Below-ground processes play a key role in the global carbon (C) cycle because they regulate storage of large quantities of C, and are potentially very sensitive to direct and indirect effects of elevated...

  11. A hybrid model for mapping relative differences in belowground biomass and root: Shoot ratios using spectral reflectance, foliar N and plant biophysical data within coastal marsh

    Science.gov (United States)

    Jessica L. O'Connell,; Byrd, Kristin B.; Maggi Kelly,

    2015-01-01

    Broad-scale estimates of belowground biomass are needed to understand wetland resiliency and C and N cycling, but these estimates are difficult to obtain because root:shoot ratios vary considerably both within and between species. We used remotely-sensed estimates of two aboveground plant characteristics, aboveground biomass and % foliar N to explore biomass allocation in low diversity freshwater impounded peatlands (Sacramento-San Joaquin River Delta, CA, USA). We developed a hybrid modeling approach to relate remotely-sensed estimates of % foliar N (a surrogate for environmental N and plant available nutrients) and aboveground biomass to field-measured belowground biomass for species specific and mixed species models. We estimated up to 90% of variation in foliar N concentration using partial least squares (PLS) regression of full-spectrum field spectrometer reflectance data. Landsat 7 reflectance data explained up to 70% of % foliar N and 67% of aboveground biomass. Spectrally estimated foliar N or aboveground biomass had negative relationships with belowground biomass and root:shoot ratio in both Schoenoplectus acutus and Typha, consistent with a balanced growth model, which suggests plants only allocate growth belowground when additional nutrients are necessary to support shoot development. Hybrid models explained up to 76% of variation in belowground biomass and 86% of variation in root:shoot ratio. Our modeling approach provides a method for developing maps of spatial variation in wetland belowground biomass.

  12. Dynamic Labeling Reveals Temporal Changes in Carbon Re-Allocation within the Central Metabolism of Developing Apple Fruit

    Directory of Open Access Journals (Sweden)

    Wasiye F. Beshir

    2017-10-01

    Full Text Available In recent years, the application of isotopically labeled substrates has received extensive attention in plant physiology. Measuring the propagation of the label through metabolic networks may provide information on carbon allocation in sink fruit during fruit development. In this research, gas chromatography coupled to mass spectrometry based metabolite profiling was used to characterize the changing metabolic pool sizes in developing apple fruit at five growth stages (30, 58, 93, 121, and 149 days after full bloom using 13C-isotope feeding experiments on hypanthium tissue discs. Following the feeding of [U-13C]glucose, the 13C-label was incorporated into the various metabolites to different degrees depending on incubation time, metabolic pathway activity, and growth stage. Evidence is presented that early in fruit development the utilization of the imported sugars was faster than in later developmental stages, likely to supply the energy and carbon skeletons required for cell division and fruit growth. The declined 13C-incorporation into various metabolites during growth and maturation can be associated with the reduced metabolic activity, as mirrored by the respiratory rate. Moreover, the concentration of fructose and sucrose increased during fruit development, whereas concentrations of most amino and organic acids and polyphenols declined. In general, this study showed that the imported compounds play a central role not only in carbohydrate metabolism, but also in the biosynthesis of amino acid and related protein synthesis and secondary metabolites at the early stage of fruit development.

  13. Vulnerability and resilience to droughts in South-West USA: carbon allocation and impact on wood and evaporative anatomy

    Science.gov (United States)

    Guerin, M. F.; von Arx, G.; McDowell, N. G.; Pockman, W.; Andreu-Hayles, L.; Gentine, P.

    2015-12-01

    Survival and distribution of conifers across the globe will depend on their adaptive potential to the new climatic conditions (warmer, more droughts, heat waves). Recent studies predicting forest evolution have mainly focused on understanding tree mortality processes (hydraulic failure, carbon starvation, biotic stresses). These explicit causes of mortality are also the result of unsuccessful adaptation on a longer period. Using a 7 years drought-irrigation experiment in New Mexico, USA, we investigated the response to water availability on structure-function interactions at the tree level. Bridging dendrology and physiology on multiple individuals of local Pinion pine, we observe a structural dynamics in i) wood anatomy ii) evaporative anatomy and a resulting functional dynamics in i) leaf water potential and ii) water use efficiency on multiple time scales (daily to interannual). These results emphasize the tight coupling between carbon allocation and the surface hydrologic cycle on longer time scales and its impact on resilience and mortality, which is not included in current generation land-surface models. figure: Wood anatomy obtained from a 5.2mm core of a Pinion Edulis from the experimental site - illustrating the variability of the water transport capacities accross years

  14. Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

    Science.gov (United States)

    Verbeeck, Hans; Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Kearsley, Elizabeth; Cizungu, Landry; Boeckx, Pascal

    2017-04-01

    Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Central Africa, focussing on shifts in carbon allocation, forest structure, nutrient cycling and functional composition. The Ecuadorian transect has 16 plots (40 by 40 m) and ranges from 400 to 3000 m.a.s.l., and the Rwandan transect has 20 plots (40 by 40 m) from 1500 to 3000 m.a.s.l. All plots were inventoried and canopy, litter and soil were extensively sampled. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed altitudinal adaption mechanisms are. This could provide us with vital information of the ecological responses of both biomes to future global change scenarios. Additionally, comparison of nutrient shifts and trait-based functional composition allows us to compare the biogeochemical cycles of African and South-American tropical forests.

  15. Global climate change and above- belowground insect herbivore interactions.

    Directory of Open Access Journals (Sweden)

    Scott Wesley McKenzie

    2013-10-01

    Full Text Available Predicted changes to the Earth’s climate are likely to affect above-belowground interactions. Our understanding is limited, however, by past focus on two-species aboveground interactions mostly ignoring belowground influences. Despite their importance to ecosystem processes, there remains a dearth of empirical evidence showing how climate change will affect above-belowground interactions. The responses of above- and belowground organisms to climate change are likely to differ given the fundamentally different niches they inhabit. Yet there are few studies that address the biological and ecological reactions of belowground herbivores to environmental conditions in current and future climates. Even fewer studies investigate the consequences of climate change for above-belowground interactions between herbivores and other organisms; those that do provide no evidence of a directed response. This paper highlights the importance of considering the belowground fauna when making predictions on the effects of climate change on plant-mediated interspecific interactions.

  16. GENOME-ENABLED DISCOVERY OF CARBON SEQUESTRATION GENES IN POPLAR

    Energy Technology Data Exchange (ETDEWEB)

    DAVIS J M

    2007-10-11

    Plants utilize carbon by partitioning the reduced carbon obtained through photosynthesis into different compartments and into different chemistries within a cell and subsequently allocating such carbon to sink tissues throughout the plant. Since the phytohormones auxin and cytokinin are known to influence sink strength in tissues such as roots (Skoog & Miller 1957, Nordstrom et al. 2004), we hypothesized that altering the expression of genes that regulate auxin-mediated (e.g., AUX/IAA or ARF transcription factors) or cytokinin-mediated (e.g., RR transcription factors) control of root growth and development would impact carbon allocation and partitioning belowground (Fig. 1 - Renewal Proposal). Specifically, the ARF, AUX/IAA and RR transcription factor gene families mediate the effects of the growth regulators auxin and cytokinin on cell expansion, cell division and differentiation into root primordia. Invertases (IVR), whose transcript abundance is enhanced by both auxin and cytokinin, are critical components of carbon movement and therefore of carbon allocation. Thus, we initiated comparative genomic studies to identify the AUX/IAA, ARF, RR and IVR gene families in the Populus genome that could impact carbon allocation and partitioning. Bioinformatics searches using Arabidopsis gene sequences as queries identified regions with high degrees of sequence similarities in the Populus genome. These Populus sequences formed the basis of our transgenic experiments. Transgenic modification of gene expression involving members of these gene families was hypothesized to have profound effects on carbon allocation and partitioning.

  17. Salinity Effects on Photosynthesis, Carbon Allocation, and Nitrogen Assimilation in the Red Alga, Gelidium coulteri1

    Science.gov (United States)

    Macler, Bruce A.

    1988-01-01

    The long-term effects of altered salinities on the physiology of the intertidal red alga Gelidium coulteri Harv. were assessed. Plants were transfered from 30 grams per liter salinity to media with salinities from 0 to 50 grams per liter. Growth rate, agar, photosynthesis, respiration, and various metabolites were quantified after 5 days and 5 weeks adaptation. After 5 days, growth rates were lower for plants at all altered salinities. Growth rates recovered from these values with 5 weeks adaptation, except for salinities of 10 grams per liter and below, where tissues bleached and died. Photosynthetic O2 evolution was lower than control values at both higher and lower salinities after 5 days and did not change over time. Carbon fixation at the altered salinities was unchanged after 5 days, but decreased below 25 grams per liter and above 40 grams per liter after 5 weeks. Respiration increased at lower salinities. Phycobili-protein and chlorophyll were lower for all altered salinities after 5 days. These decreases continued at lower salinities, then were stable after 5 weeks. Chlorophyll recovered over time at higher salinities. Decreases in protein at lower salinities were quantitatively attributable to phycobili-protein loss. Total N levels and C:N ratios were nearly constant across all salinities tested. Carbon flow into glutamate and aspartate decreased with both decreasing and increasing salinities. Glycine, serine, and glycolate levels increased with both increasing and decreasing salinity, indicating a stimulation of photorespiration. The cell wall component agar increased with decreasing salinity, although biosynthesis was inhibited at both higher and lower salinities. The storage compound floridoside increased with increasing salinity. The evidence suggests stress responses to altered salinities that directly affected photosynthesis, respiration, and nitrogen assimilation and indirectly affected photosynthate flow. At low salinities, respiration and

  18. Salinity Effects on Photosynthesis, Carbon Allocation, and Nitrogen Assimilation in the Red Alga, Gelidium coulteri.

    Science.gov (United States)

    Macler, B A

    1988-11-01

    The long-term effects of altered salinities on the physiology of the intertidal red alga Gelidium coulteri Harv. were assessed. Plants were transfered from 30 grams per liter salinity to media with salinities from 0 to 50 grams per liter. Growth rate, agar, photosynthesis, respiration, and various metabolites were quantified after 5 days and 5 weeks adaptation. After 5 days, growth rates were lower for plants at all altered salinities. Growth rates recovered from these values with 5 weeks adaptation, except for salinities of 10 grams per liter and below, where tissues bleached and died. Photosynthetic O(2) evolution was lower than control values at both higher and lower salinities after 5 days and did not change over time. Carbon fixation at the altered salinities was unchanged after 5 days, but decreased below 25 grams per liter and above 40 grams per liter after 5 weeks. Respiration increased at lower salinities. Phycobili-protein and chlorophyll were lower for all altered salinities after 5 days. These decreases continued at lower salinities, then were stable after 5 weeks. Chlorophyll recovered over time at higher salinities. Decreases in protein at lower salinities were quantitatively attributable to phycobili-protein loss. Total N levels and C:N ratios were nearly constant across all salinities tested. Carbon flow into glutamate and aspartate decreased with both decreasing and increasing salinities. Glycine, serine, and glycolate levels increased with both increasing and decreasing salinity, indicating a stimulation of photorespiration. The cell wall component agar increased with decreasing salinity, although biosynthesis was inhibited at both higher and lower salinities. The storage compound floridoside increased with increasing salinity. The evidence suggests stress responses to altered salinities that directly affected photosynthesis, respiration, and nitrogen assimilation and indirectly affected photosynthate flow. At low salinities, respiration and

  19. A Dynamic Programming-Based Sustainable Inventory-Allocation Planning Problem with Carbon Emissions and Defective Item Disposal under a Fuzzy Random Environment

    Directory of Open Access Journals (Sweden)

    Kai Kang

    2018-01-01

    Full Text Available There is a growing concern that business enterprises focus primarily on their economic activities and ignore the impact of these activities on the environment and the society. This paper investigates a novel sustainable inventory-allocation planning model with carbon emissions and defective item disposal over multiple periods under a fuzzy random environment. In this paper, a carbon credit price and a carbon cap are proposed to demonstrate the effect of carbon emissions’ costs on the inventory-allocation network costs. The percentage of poor quality products from manufacturers that need to be rejected is assumed to be fuzzy random. Because of the complexity of the model, dynamic programming-based particle swarm optimization with multiple social learning structures, a DP-based GLNPSO, and a fuzzy random simulation are proposed to solve the model. A case is then given to demonstrate the efficiency and effectiveness of the proposed model and the DP-based GLNPSO algorithm. The results found that total costs across the inventory-allocation network varied with changes in the carbon cap and that carbon emissions’ reductions could be utilized to gain greater profits.

  20. Genotypic variation in transpiration efficiency, carbon-isotope discrimination and carbon allocation during early growth in sunflower

    International Nuclear Information System (INIS)

    Virgona, J.M.; Farquhar, G.D.; Hubick, K.T.; Rawson, H.M.; Downes, R.W.

    1990-01-01

    Transpiration efficiency of dry matter production (W), carbon-isotope discrimination (Δ) and dry matter partitioning were measured on six sunflower (Helianthus annuus L.) genotypes grown for 32 days in a glasshouse. Two watering regimes, one well watered (HW) and the other delivering half the water used by the HW plants (LW), were imposed. Four major results emerged from this study: Three was significant genotypic variation in W in sunflower and this was closely reflected in Δ for both watering treatments; the low watering regime caused a decrease in Δ but no change in W; nonetheless the genotypic ranking for either Δ or W was not significantly altered by water stress; a positive correlation between W and biomass accumulation occurred among genotypes of HW plants; ρ, the ratio of total plant carbon content to leaf area, was positively correlated with W and negatively correlated with Δ. These results are discussed with reference to the connection between transpiration efficiency and plant growth, indicating that Δ can be used to select for W among young sunflower plants. However, selection for W may be accompanied by changes in other important plant growth characteristics such as ρ. 19 refs., 4 figs

  1. Above and belowground controls on litter decomposition in semiarid ecosystems: effects of solar radiation, water availability and litter quality

    Science.gov (United States)

    Austin, A. T.; Araujo, P. I.; Leva, P. E.; Ballare, C. L.

    2008-12-01

    The integrated controls on soil organic matter formation in arid and semiarid ecosystems are not well understood and appear to stem from a number of interacting controls affecting above- and belowground carbon turnover. While solar radiation has recently been shown to have an important direct effect on carbon loss in semiarid ecosystems as a result of photochemical mineralization of aboveground plant material, the mechanistic basis for photodegradative losses is poorly understood. In addition, there are large potential differences in major controls on above- and belowground decomposition in low rainfall ecosystems. We report on a mesocosm and field study designed to examine the relative importance of different wavelengths of solar radiation, water availability, position of senescent material above- and belowground and the importance of carbon litter quality in determining rates of abiotic and biotic decomposition. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position-litter type and position-pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. In the field site, using plastic filters which attenuated different wavelengths of natural solar radiation, we found a highly significant effect of radiation exclusion on mass loss and demonstrated that both UV-A and short-wave visible light can have important impacts on photodegradative carbon losses. The combination of position and litter quality effects on litter decomposition appear to be critical for the

  2. Linking root hydraulic properties to carbon allocation patterns in annual plant

    Science.gov (United States)

    Hosseini, A.; Ewers, B. E.; Adjesiwor, A. T.; Kniss, A. R.

    2017-12-01

    Incorporation of root structure and function into biophysical models is an important tool to predict plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils. Most of the models describing root water uptake (RWU) are based on semi-empirical (i.e. built on physiological hypotheses, but still combined with empirical functions) approaches and hydraulic parameters involved are hardly available. Root conductance is essential to define the interaction between soil-to-root and canopy-to-atmosphere. Also root hydraulic limitations to water flow can impact gas exchange rates and plant biomass partitioning. In this study, sugar beet (B. vulgaris) seeds under two treatments, grass (Kentucky bluegrass) and no grass (control), were planted in 19 L plastic buckets in June 2016. Photosynthetic characteristics (e.g. gas exchange and chlorophyll fluorescence), leaf morphology and anatomy, root morphology and above and below ground biomass of the plants was monitored at 15, 30, 50, 70 and 90 days after planting (DAP). Further emphasis was placed on the limits to water flow by coupling of hydraulic conductance (k) whole root-system with water relation parameters and gas exchange rates in fully established plants.

  3. Long-term climate change effects on dynamics of microorganisms and carbon in the root-zone

    DEFF Research Database (Denmark)

    Reinsch, Sabine

    Climate change factors such as elevated CO2 concentration, warming and changes in precipitation patterns have been shown to affect terrestrial carbon (C) cycling. The objective of this Ph.D. project is to track recently assimilated C into belowground compartments to investigate the effects...... of climate change on belowground C allocation. The impacts of climate change as single and combined treatments were applied to heath/grassland vegetation and the short-term terrestrial C turnover was investigated using in-situ 13CO2 pulse-labeling. We developed a mobile and low-cost pulse-labeling setup...... have major impacts on the C balance under changing climatic conditions. A comparison of C allocation under ambient and simulated future climatic conditions showed that the terrestrial C balance might be changed by reducing soil organic matter mineralization. Our results suggest that the impact...

  4. Production physiology and morphology of Populus species and their hybrids grown under short rotation. III. Seasonal carbon allocation patterns from branches

    Energy Technology Data Exchange (ETDEWEB)

    Scarascia-Mugnozza, G.E.; Hinckley, T.M.; Stettler, R.F. [Washington Univ., College of Forest Resources, Seattle, WA (United States)

    1999-09-01

    A study was carried out to compare highly productive cones, in the Pacific Northwest, in terms of contrasting growth and morphology. The objective of the study was to determine seasonal differences in carbon allocation patterns among 1- and 2-year old trees of Populus deltoides Bartr, and 2 of their interspecific hybrids. The study examined if there are different patterns of carbon allocation associated with the more productive poplar clones, how these patterns vary over the course of the growing season and from the first and the second year, if sylleptic branches vary from proleptic branches in their carbon allocation patterns, if there are the translocation patterns within branches and the degree of branch autonomy that exists with sylleptic and proleptic branches and if these patterns vary during the growing season. Previous findings on general patterns of carbon allocation in poplar clones were confirmed, and new dimensions were introduced regarding differences among branch types and clones. In the first year, carbon export from sylleptic branches increased over the growing season, and they export primarily toward the lower stem and roots. In the second year, important differences in translocation efficiency occurred among branch types with the sylleptic branches contributing more than proleptic branches, on a per unit mass basis, to the growth of the tree. Transport patterns, within branches and among branches of different order, were similar to those in the main stem, with phenology playing an important role in controlling the sink activity of the apical portion of the growing axis. Exchange of photosynthates between adjacent branches of the same order or between branches and main stem leaves are minimal, supporting an hypothesis of branch autonomy. 29 refs., 5 tabs., 4 figs.

  5. Cardenolides, induced responses, and interactions between above- and belowground herbivores of milkweed (Asclepias spp.).

    Science.gov (United States)

    Rasmann, Sergio; Agrawal, Anurag A; Cook, Susan C; Erwin, Alexis C

    2009-09-01

    Theory has long predicted allocation patterns for plant defense against herbivory, but only recently have both above- and belowground plant defenses been considered simultaneously. Milkweeds in the genus Asclepias are a classic chemically defended clade of plants with toxic cardenolides (cardiac glycosides) and pressurized latex employed as anti-herbivore weapons. Here we combine a comparative approach to investigate broadscale patterns in allocation to root vs. shoot defenses across species with a species-specific experimental approach to identify the consequences of defense allocational shifts on a specialist herbivore. Our results show phylogenetic conservatism for inducibility of shoot cardenolides by an aboveground herbivore, with only four closely related tropical species showing significant induction; the eight temperate species examined were not inducible. Allocation to root and shoot cardenolides was positively correlated across species, and this relationship was maintained after accounting for phylogenetic nonindependence. In contrast to long-standing theoretical predictions, we found no evidence for a trade-off between constitutive and induced cardenolides; indeed the two were positively correlated across species in both roots and shoots. Finally, specialist root and shoot herbivores of common milkweed (A. syriaca) had opposing effects on latex production, and these effects had consequences for caterpillar growth consistent with latex providing resistance. Although cardenolides were not affected by our treatments, A. syriaca allocated 40% more cardenolides to shoots over roots. We conclude that constitutive and inducible defenses are not trading off across plant species, and shoots of Asclepias are more inducible than roots. Phylogenetic conservatism cannot explain the observed patterns of cardenolide levels across species, but inducibility per se was conserved in a tropical clade. Finally, given that above- and belowground herbivores can systemically

  6. Positive responses of belowground C dynamics to nitrogen enrichment in China.

    Science.gov (United States)

    Deng, Lei; Peng, Changhui; Zhu, Guangyu; Chen, Lei; Liu, Yulin; Shangguan, Zhouping

    2018-03-01

    Determining how nitrogen (N) impacts ecosystem carbon (C) cycling is critical to using C sequestration to offset anthropogenic CO 2 emissions. The N deposition rate in China is higher than the global average; however, many results of N enrichment experiments in China have not been included in global syntheses. In this study, we assembled a large dataset that comprised 124 published studies concerning N addition experiments, including 570 observations at 127 sites across China, to quantify the responses of belowground C dynamics to N enrichment in terrestrial ecosystems in China by a meta-analysis. The results showed that overall soil organic C, dissolved organic C (DOC) and soil microbial biomass C (MBC) increased by 1.8, 7.4, and 8.8%, respectively (Penrichment; belowground biomass and litter increased by 14.6 and 24.4%, respectively (Penrichment promoted C inputs into the soil mainly by increasing litter and belowground biomass inputs. Additionally, N enrichment increased C output by increasing soil respiration. Land use type and N addition level had different impacts on the soil C pool and on soil respiration. DOC, MBC, and litter exhibited more positive responses to N deposition in cooler and more arid regions than in other regions. The meta-analysis indicated that N enrichment had a positive impact on belowground C cycles in China. Climate played a greater role than did N deposition level in affecting processes of ecosystem C cycling. Moreover, belowground C cycle processes are determined by complicated interactions among land use type, N enrichment, and climate. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Rain-Shelter Cultivation Modifies Carbon Allocation in the Polyphenolic and Volatile Metabolism of Vitis vinifera L. Chardonnay Grapes

    Science.gov (United States)

    Han, Mei-Mei; Yang, Xiao-Fan; Li, Zheng; Wang, Jun; Pan, Qiu-Hong

    2016-01-01

    This study investigated the effect of rain-shelter cultivation on the biosynthesis of flavonoids and volatiles in grapes, with an aim of determining whether rain-shelter application could help to improve the sensory attributes and quality of grapes. Vitis vinifera L. Chardonnay grapes, grown in the Huaizhuo basin region of northern China, were selected within two consecutive years. A rain-shelter roof was constructed using a colorless polyethylene (PE) film with a light transmittance of 80%. Results showed that rain-shelter treatment did not affect the accumulation of soluble solids during grape maturation. However, the allocation of assimilated carbon in phenolic and volatile biosynthetic pathways varied significantly, leading to alterations in polyphenolic and volatile profiles. The rain-shelter cultivation enhanced the concentration of flavan-3-ols via the flavonoid-3’5’-hydroxylase (F3’5’H) pathway, but reduced the level of flavonols and flavan-3-ols via the flavonoid-3’-hydroxylase (F3’H) pathway. In addition, the rain-shelter cultivation significantly enhanced the synthesis of fatty acid-derived volatiles, isoprene-derived terpenoids and amino acid-derived branched-chain aliphatics, but led to a decrease in the accumulation of isoprene-derived norisoprenoids and amino acid-derived benzenoids. Principal component analysis revealed some key compounds that differentiated the grapes cultivated under open-field and rain-shelter conditions. Moreover, the effect of the rain-shelter application on the accumulation of these compounds appeared to be vintage dependent. The alteration of their profiles caused by the rain-shelter treatment was significant in the vintage that received higher rainfall, which usually took place in the first rapid growth and veraison phases. PMID:27218245

  8. The Ground Rules for Effective OBAs: Principles for Addressing Carbon-Pricing Competitiveness Concerns through the Use of Output-Based Allocations

    Directory of Open Access Journals (Sweden)

    Sarah Dobson

    2017-06-01

    Full Text Available The federal government’s decision to impose a minimum national price on carbon emissions has the potential to make certain businesses in the country less competitive. Specifically, there are emissions-intensive and trade-exposed industries across Canada that compete against producers from other jurisdictions where governments do not put a price on carbon. For these industries, the obligation to pay a carbon price creates a competitive disadvantage. Specifically, these businesses will face higher costs and may encounter a loss of market share to international competitors from jurisdictions that lack the same emission-control measures. That not only hurts Canadian businesses, it could also negate any emissions reductions that carbon pricing in Canada achieves on a global scale. The federal government has opted to protect such emissions-intensive, tradeexposed businesses using subsidies called output-based allocations (OBAs. This is the same system that Alberta is introducing through its forthcoming Carbon Competiveness Regulation. It also shares certain similarities with cap-and-trade programs, such as those in Ontario and Quebec, which provide free allocations of emissions permits to certain firms. OBAs are a desirable complementary policy to a carbon price as they maintain the incentive for producers to invest in production methods and facilities that are less emissions intensive. So while producers are still, nevertheless, subsidized to offset the tax burden of the carbon price, they will, under an OBA system, see greater benefits the more they work to reduce their emissions intensity. Still, to function most effectively and most efficiently, an OBA policy should follow certain key principles. The most critical principle in the design of an OBA policy is ensuring that OBAs are allocated to facilities independent of their individual emission levels, and allocated equally (on a per unit basis to facilities producing the same product. One of the

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

    International Nuclear Information System (INIS)

    Vivin, P.; Guehl, J.M.

    1997-01-01

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

  10. Transcriptional control of monolignol biosynthesis in Pinus taeda: factors affecting monolignol ratios and carbon allocation in phenylpropanoid metabolism

    Science.gov (United States)

    Anterola, Aldwin M.; Jeon, Jae-Heung; Davin, Laurence B.; Lewis, Norman G.

    2002-01-01

    Transcriptional profiling of the phenylpropanoid pathway in Pinus taeda cell suspension cultures was carried out using quantitative real time PCR analyses of all known genes involved in the biosynthesis of the two monolignols, p-coumaryl and coniferyl alcohols (lignin/lignan precursors). When the cells were transferred to a medium containing 8% sucrose and 20 mm potassium iodide, the monolignol/phenylpropanoid pathway was induced, and transcript levels for phenylalanine ammonia lyase, cinnamate 4-hydroxylase, p-coumarate 3-hydroxylase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase, and cinnamyl alcohol dehydrogenase were coordinately up-regulated. Provision of increasing levels of exogenously supplied Phe to saturating levels (40 mm) to the induction medium resulted in further up-regulation of their transcript levels in the P. taeda cell cultures; this in turn was accompanied by considerable increases in both p-coumaryl and coniferyl alcohol formation and excretion. By contrast, transcript levels for both cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase were only slightly up-regulated. These data, when considered together with metabolic profiling results and genetic manipulation of various plant species, reveal that carbon allocation to the pathway and its differential distribution into the two monolignols is controlled by Phe supply and differential modulation of cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase activities, respectively. The coordinated up-regulation of phenylalanine ammonia lyase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase and cinnamyl alcohol dehydrogenase in the presence of increasing concentrations of Phe also indicates that these steps are not truly rate-limiting, because they are modulated according to metabolic demand. Finally, the transcript profile of a putative acid/ester O-methyltransferase, proposed as an alternative catalyst for O-methylation leading

  11. Below-ground biomass production and allometric relationships of eucalyptus coppice plantation in the central highlands of Madagascar

    International Nuclear Information System (INIS)

    Razakamanarivo, Ramarson H.; Razakavololona, Ando; Razafindrakoto, Marie-Antoinette; Vieilledent, Ghislain; Albrecht, Alain

    2012-01-01

    Short rotations of Eucalyptus plantations under coppice regime are extensively managed for wood production in Madagascar. Nevertheless, little is known about their biomass production and partitioning and their potential in terms of carbon sequestration. If above-ground biomass (AGB) can be estimated based on established allometric relations, below-ground (BGB) estimates are much less common. The aim of this work was to develop allometric equations to estimate biomass of these plantations, mainly for the root components. Data from 9 Eucalyptus robusta stands (47–87 years of plantation age, 3–5 years of coppice-shoot age) were collected and analyzed. Biomass of 3 sampled trees per stand was determined destructively. Dry weight of AGB components (leaves, branches and stems) were estimated as a function of basal area of all shoots per stump and dry weight for BGB components (mainly stump, coarse root (CR) and medium root (MR)) were estimated as a function of stump circumference. Biomass was then computed using allometric equations from stand inventory data. Stand biomass ranged from 102 to 130 Mg ha −1 with more than 77% contained in the BGB components. The highest dry weight was allocated in the stump and in the CR (51% and 42% respectively) for BGB parts and in the stem (69%) for AGB part. Allometric relationships developed herein could be applied to other Eucalyptus plantations which present similar stand density and growing conditions; anyhow, more is needed to be investigated in understanding biomass production and partitioning over time for this kind of forest ecosystem. -- Highlights: ► We studied the potential of old eucalyptus coppices in Madagascar to mitigate global warming. ► Biomass measurement, mainly for below-ground BGB (stump, coarse-medium-and fine roots) was provided. ► BGB allometry relationships for short rotation forestry under coppice were established. ► BGB were found to be important with their 102-130MgC ha -1 (<77% of the C in

  12. Carbon allocation and element composition in four Chlamydomonas mutants defective in genes related to the CO2 concentrating mechanism

    Czech Academy of Sciences Publication Activity Database

    Memmola, F.; Mukherjee, B.; Moroney, James V.; Giordano, Mario

    2014-01-01

    Roč. 121, 2-3 (2014), s. 201-211 ISSN 0166-8595 Institutional support: RVO:61388971 Keywords : Chlamydomonas mutants * carbon * carbon dioxide * elemental stoichiometry Subject RIV: EE - Microbiology, Virology Impact factor: 3.502, year: 2014

  13. Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties.

    Science.gov (United States)

    Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

  14. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents.

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W

    2016-11-04

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems.

  15. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W.

    2016-01-01

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems. PMID:27811992

  16. Allometric growth and allocation in forests: a perspective from FLUXNET.

    Science.gov (United States)

    Wolf, Adam; Field, Christopher B; Berry, Joseph A

    2011-07-01

    To develop a scheme for partitioning the products of photosynthesis toward different biomass components in land-surface models, a database on component mass and net primary productivity (NPP), collected from FLUXNET sites, was examined to determine allometric patterns of allocation. We found that NPP per individual of foliage (Gfol), stem and branches (Gstem), coarse roots (Gcroot) and fine roots (Gfroot) in individual trees is largely explained (r2 = 67-91%) by the magnitude of total NPP per individual (G). Gfol scales with G isometrically, meaning it is a fixed fraction of G ( 25%). Root-shoot trade-offs were manifest as a slow decline in Gfroot, as a fraction of G, from 50% to 25% as stands increased in biomass, with Gstem and Gcroot increasing as a consequence. These results indicate that a functional trade-off between aboveground and belowground allocation is essentially captured by variations in G, which itself is largely governed by stand biomass and only secondarily by site-specific resource availability. We argue that forests are characterized by strong competition for light, observed as a race for individual trees to ascend by increasing partitioning toward wood, rather than by growing more leaves, and that this competition stronglyconstrains the allocational plasticity that trees may be capable of. The residual variation in partitioning was not related to climatic or edaphic factors, nor did plots with nutrient or water additions show a pattern of partitioning distinct from that predicted by G alone. These findings leverage short-term process studies of the terrestrial carbon cycle to improve decade-scale predictions of biomass accumulation in forests. An algorithm for calculating partitioning in land-surface models is presented.

  17. Partitioning CO2 fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Davidson, Eric [Univ. of Arizona, Tucson, AZ (United States); Finzi, Adrien [Boston Univ., MA (United States); Wehr, Richdard [Harvard Univ., Cambridge, MA (United States); Moorcroft, Paul [Harvard Univ., Cambridge, MA (United States)

    2016-01-28

    1. Objectives This project combines automated in situ observations of the isotopologues of CO2 with root observations, novel experimental manipulations of belowground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. aboveground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: A. Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics ; B. Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated belowground using measurements of root growth and indices of belowground autotrophic vs. heterotrophic respiration (via trenched plots and isotope measurements); C. Testing whether plant allocation of carbon belowground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and D. Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2). 2. Highlights Accomplishments: • Our isotopic eddy flux record has completed its 5th full year and has been used to independently estimate ecosystem-scale respiration and photosynthesis. • Soil surface chamber isotopic flux measurements were carried out during three growing seasons, in conjunction with a trenching manipulation. Key findings to date (listed by objective): A. Partitioning of Net Ecosystem Exchange: 1. Ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light (the “Kok effect”) at the ecosystem scale. 2. Because it neglects the Kok effect, the standard NEE partitioning approach overestimates ecosystem photosynthesis (by ~25%) and

  18. Partitioning between primary and secondary metabolism of carbon allocated to roots in four maize genotypes under water deficit and its effects on productivity

    Directory of Open Access Journals (Sweden)

    Alyne Oliveira Lavinsky

    2015-10-01

    Full Text Available Plants may respond to drought by altering biomass allocation to shoots and roots or by changing the metabolic activities in these organs. To determine how drought changes the partitioning of carbon allocated to growth and secondary metabolism in maize roots and how it affects photosynthesis (A and productivity in maize, we evaluated leaf gas exchange, yield componentes, root morphology, and primary and secondary metabolites including total soluble sugars (TSS, starch (S, phenolics (PHE, and lignin (LIG. Data were collected from pot-grown plants of four maize genotypes: BRS 1010 and 2B710 (sensitive genotypes and DKB390 and BRS1055 (tolerant genotypes under two soil water tensions: field capacity (FC, − 18 kPa and water deficit (WD, − 138 kPa. WD was applied at the pre-flowering stage for 12 days and then the water supply was restored and maintained at optimum levels until the end of the cycle. For genotype BRS 1055 under FC, the greatest A did not result in greater grain biomass (DGB because the accumulated photoassimilates had already filled the cells, and thus the excessive TSS synthesized in leaves was allocated to roots in large amounts. However, the sharp decrease in A caused by WD imposition in this genotype did not affect the influx pressure of leaf TSS, which was due largely to conversion of primary metabolites to PHE compounds to increase the length of fine roots. In leaves of DKB390 under WD, both S and TSS were reduced, whereas PHE were increased to prevent excessive water loss and xylem cavitation. Under WD, both BRS1010 and 2B710 genotypes displayed reduced allocation of biomass to shoots and roots and LIG content in leaves, as well as lower A and DGB values. In BRS1010 this response was coupled to S decrease in leaves and TSS increase in roots, whereas in 2B710 there was a concomitant S increase in roots.

  19. Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements

    Directory of Open Access Journals (Sweden)

    D. Zanotelli

    2013-05-01

    Full Text Available Carbon use efficiency (CUE, the ratio of net primary production (NPP over gross primary production (GPP, is a functional parameter that could possibly link the current increasingly accurate global GPP estimates with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, NPP and allocation patterns in different plant organs in an apple orchard during a complete year (2010. We applied a measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. We found that in the apple orchard, both net ecosystem production and gross primary production on a yearly basis, 380 ± 30 g C m−2 and 1263 ± 189 g C m−2 respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruit: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. The CUE, with an annual average of 0.71

  20. Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy-covariance, biometric and continuous soil chamber measurements

    Science.gov (United States)

    Zanotelli, D.; Montagnani, L.; Manca, G.; Tagliavini, M.

    2012-10-01

    Carbon use efficiency (CUE) is a functional parameter that could possibly link the current increasingly accurate global estimates of gross primary production with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, net primary production (NPP) and allocation patterns in different plant organs in an apple orchard during a complete year (2010). We applied a~measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross-check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. We found that in the apple orchard both net ecosystem production and gross primary production on yearly basis, 380 ± 30 g C m-2 and 1263 ± 189 g C m-2 respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruits: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls) contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. The CUE, with an annual average of 0.71 ± 0.09, was higher than the previously suggested

  1. Net primary productivity, allocation pattern and carbon use efficiency in an apple orchard assessed by integrating eddy covariance, biometric and continuous soil chamber measurements

    Science.gov (United States)

    Zanotelli, D.; Montagnani, L.; Manca, G.; Tagliavini, M.

    2013-05-01

    Carbon use efficiency (CUE), the ratio of net primary production (NPP) over gross primary production (GPP), is a functional parameter that could possibly link the current increasingly accurate global GPP estimates with those of net ecosystem exchange, for which global predictors are still unavailable. Nevertheless, CUE estimates are actually available for only a few ecosystem types, while information regarding agro-ecosystems is scarce, in spite of the simplified spatial structure of these ecosystems that facilitates studies on allocation patterns and temporal growth dynamics. We combined three largely deployed methods, eddy covariance, soil respiration and biometric measurements, to assess monthly values of CUE, NPP and allocation patterns in different plant organs in an apple orchard during a complete year (2010). We applied a measurement protocol optimized for quantifying monthly values of carbon fluxes in this ecosystem type, which allows for a cross check between estimates obtained from different methods. We also attributed NPP components to standing biomass increments, detritus cycle feeding and lateral exports. We found that in the apple orchard, both net ecosystem production and gross primary production on a yearly basis, 380 ± 30 g C m-2 and 1263 ± 189 g C m-2 respectively, were of a magnitude comparable to those of natural forests growing in similar climate conditions. The largest differences with respect to forests are in the allocation pattern and in the fate of produced biomass. The carbon sequestered from the atmosphere was largely allocated to production of fruit: 49% of annual NPP was taken away from the ecosystem through apple production. Organic material (leaves, fine root litter, pruned wood and early fruit falls) contributing to the detritus cycle was 46% of the NPP. Only 5% was attributable to standing biomass increment, while this NPP component is generally the largest in forests. The CUE, with an annual average of 0.71 ± 0.12, was higher

  2. Carbon allocation to major metabolites in illuminated leaves is not just proportional to photosynthesis when gaseous conditions (CO2 and O2 ) vary.

    Science.gov (United States)

    Abadie, Cyril; Bathellier, Camille; Tcherkez, Guillaume

    2018-04-01

    In gas-exchange experiments, manipulating CO 2 and O 2 is commonly used to change the balance between carboxylation and oxygenation. Downstream metabolism (utilization of photosynthetic and photorespiratory products) may also be affected by gaseous conditions but this is not well documented. Here, we took advantage of sunflower as a model species, which accumulates chlorogenate in addition to sugars and amino acids (glutamate, alanine, glycine and serine). We performed isotopic labelling with 13 CO 2 under different CO 2 /O 2 conditions, and determined 13 C contents to compute 13 C-allocation patterns and build-up rates. The 13 C content in major metabolites was not found to be a constant proportion of net fixed carbon but, rather, changed dramatically with CO 2 and O 2 . Alanine typically accumulated at low O 2 (hypoxic response) while photorespiratory intermediates accumulated under ambient conditions and at high photorespiration, glycerate accumulation exceeding serine and glycine build-up. Chlorogenate synthesis was relatively more important under normal conditions and at high CO 2 and its synthesis was driven by phosphoenolpyruvate de novo synthesis. These findings demonstrate that carbon allocation to metabolites other than photosynthetic end products is affected by gaseous conditions and therefore the photosynthetic yield of net nitrogen assimilation varies, being minimal at high CO 2 and maximal at high O 2 . © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  3. Belowground advantages in construction cost facilitate a cryptic plant invasion.

    Science.gov (United States)

    Caplan, Joshua S; Wheaton, Christine N; Mozdzer, Thomas J

    2014-04-30

    The energetic cost of plant organ construction is a functional trait that is useful for understanding carbon investment during growth (e.g. the resource acquisition vs. tissue longevity tradeoff), as well as in response to global change factors like elevated CO2 and N. Despite the enormous importance of roots and rhizomes in acquiring soil resources and responding to global change, construction costs have been studied almost exclusively in leaves. We sought to determine how construction costs of aboveground and belowground organs differed between native and introduced lineages of a geographically widely dispersed wetland plant species (Phragmites australis) under varying levels of CO2 and N. We grew plants under ambient and elevated atmospheric CO2, as well as under two levels of soil nitrogen. We determined construction costs for leaves, stems, rhizomes and roots, as well as for whole plants. Across all treatment conditions, the introduced lineage of Phragmites had a 4.3 % lower mean rhizome construction cost than the native. Whole-plant construction costs were also smaller for the introduced lineage, with the largest difference in sample means (3.3 %) occurring under ambient conditions. In having lower rhizome and plant-scale construction costs, the introduced lineage can recoup its investment in tissue construction more quickly, enabling it to generate additional biomass with the same energetic investment. Our results suggest that introduced Phragmites has had an advantageous tissue investment strategy under historic CO2 and N levels, which has facilitated key rhizome processes, such as clonal spread. We recommend that construction costs for multiple organ types be included in future studies of plant carbon economy, especially those investigating global change. Published by Oxford University Press on behalf of the Annals of Botany Company.

  4. ESG Allocations

    Data.gov (United States)

    Department of Housing and Urban Development — This report displays the Emergency Solutions Grants (ESG), formerly Emergency Shelter Grants, allocation by jurisdiction. The website allows users to look at...

  5. Top-down impact through a bottom-up mechanism: the effect of limpet grazing on growth, productivity and carbon allocation of Zostera marina L. (eelgrass).

    Science.gov (United States)

    Zimmerman, Richard C; Kohrs, Donald G; Alberte, Randall S

    1996-09-01

    The unusual appearance of a commensal eelgrass limpet [Tectura depicta (Berry)] from southern California at high density (up to 10 shoot -1 ) has coincided with the catastrophic decline of a subtidal Zostera marina L. meadow in Monterey Bay, California. Some commensal limpets graze the chloroplast-rich epidermis of eelgrass leaves, but were not known to affect seagrass growth or productivity. We evaluated the effect on eelgrass productivity of grazing by limpets maintained at natural densities (8±2 shoot -1 ) in a natural light mesocosm for 45 days. Growth rates, carbon reserves, root proliferation and net photosynthesis of grazed plants were 50-80% below those of ungrazed plants, but biomass-specific respiration was unaffected. The daily period of irradiance-saturated photosynthesis (H sat ) needed to maintain positive carbon balance in grazed plants approached 13.5 h, compared with 5-6 h for ungrazed plants. The amount of carbon allocated to roots of ungrazed plants was 800% higher than for grazed plants. By grazing the chlorophyll-rich epidermis, T. depicta induced carbon limitation in eelgrass growing in an other-wise light-replete environment. Continued northward movement of T. depicta, may have significant impacts on eelgrass production and population dynamics in the northeast Pacific, even thought this limpet consumes very little plant biomass. This interaction is a dramatic example of top-down control (grazing/predation) of eelgrass productivity and survival operating via a bottom-up mechanism (photosynthesis limitation).

  6. Forest biomass, productivity and carbon cycling along a rainfall gradient in West Africa.

    Science.gov (United States)

    Moore, Sam; Adu-Bredu, Stephen; Duah-Gyamfi, Akwasi; Addo-Danso, Shalom D; Ibrahim, Forzia; Mbou, Armel T; de Grandcourt, Agnès; Valentini, Riccardo; Nicolini, Giacomo; Djagbletey, Gloria; Owusu-Afriyie, Kennedy; Gvozdevaite, Agne; Oliveras, Imma; Ruiz-Jaen, Maria C; Malhi, Yadvinder

    2018-02-01

    Net Primary Productivity (NPP) is one of the most important parameters in describing the functioning of any ecosystem and yet it arguably remains a poorly quantified and understood component of carbon cycling in tropical forests, especially outside of the Americas. We provide the first comprehensive analysis of NPP and its carbon allocation to woody, canopy and root growth components at contrasting lowland West African forests spanning a rainfall gradient. Using a standardized methodology to study evergreen (EF), semi-deciduous (SDF), dry forests (DF) and woody savanna (WS), we find that (i) climate is more closely related with above and belowground C stocks than with NPP (ii) total NPP is highest in the SDF site, then the EF followed by the DF and WS and that (iii) different forest types have distinct carbon allocation patterns whereby SDF allocate in excess of 50% to canopy production and the DF and WS sites allocate 40%-50% to woody production. Furthermore, we find that (iv) compared with canopy and root growth rates the woody growth rate of these forests is a poor proxy for their overall productivity and that (v) residence time is the primary driver in the productivity-allocation-turnover chain for the observed spatial differences in woody, leaf and root biomass across the rainfall gradient. Through a systematic assessment of forest productivity we demonstrate the importance of directly measuring the main components of above and belowground NPP and encourage the establishment of more permanent carbon intensive monitoring plots across the tropics. © 2017 John Wiley & Sons Ltd.

  7. Use of innovative groundcovers in Mediterranean afforestations: aerial and belowground effects in hybrid walnut.

    Directory of Open Access Journals (Sweden)

    Angelo Vitone

    2016-11-01

    Full Text Available Forest restoration in the Mediterranean area is particularly limited by water scarcity in summer and by weed competition, especially during the first years after establishment. The negative impact of these factors can be mitigated through environmentally friendly and cost-effective techniques which favour root development. This study describes the results of innovative weeding techniques in a reforestation carried out in a former agricultural field in Solsona, NE Spain, under Continental Mediterranean Sub-humid climate conditions. The tested weeding techniques included both novel groundcovers (based on prototypes built on a new biodegradable biopolymer, jute treated with resin and recycled rubber and reference techniques, i.e. herbicide application and polyethylene and commercial biofilm groundcovers. We studied the response of hybrid walnut (Juglans x intermedia to the application of these techniques during the first vegetative period in terms of survival, aerial growth and aboveground and belowground biomass allocation. The innovative groundcovers resulted generally in similar outcomes as the reference techniques with regard to tree survival and growth, and to better results in the case of belowground and, to a lesser extent, total tree biomass. Although preliminary, our results suggest that the tested novel groundcovers, notably the model based on treated jute, represent a promising alternative to plastic mulching and herbicide application in afforestation of agricultural lands in Mediterranean continental conditions. Besides these promising productive results, the novel groundcovers bring together relevant technical and environmental benefits, related to their use (not requiring removal or being reusable and composition, based on biodegradable or recycled materials.

  8. Potential impact of (CET) carbon emissions trading on China’s power sector: A perspective from different allowance allocation options

    DEFF Research Database (Denmark)

    Cong, Ronggang; Wei, Yi-Ming

    2010-01-01

    of traditional methods. We establish an agent-based model, CETICEM (CET Introduced China Electricity Market), of introduction of CET to China. In CETICEM, six types of agents and two markets are modeled. We find that: (1) CET internalizes environment cost; increases the average electricity price by 12......In Copenhagen climate conference China government promised that China would cut down carbon intensity 40–45% from 2005 by 2020. CET (carbon emissions trading) is an effective tool to reduce emissions. But because CET is not fully implemented in China up to now, how to design it and its potential......%; and transfers carbon price volatility to the electricity market, increasing electricity price volatility by 4%. (2) CET influences the relative cost of different power generation technologies through the carbon price, significantly increasing the proportion of environmentally friendly technologies; expensive...

  9. Partitioning CO2 fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States); Davidson, Eric [Univ. of Arizona, Tucson, AZ (United States); Finzi, Adrien [Univ. of Arizona, Tucson, AZ (United States); Wehr, Richard [Univ. of Arizona, Tucson, AZ (United States); Moorcroft, Paul [Univ. of Arizona, Tucson, AZ (United States)

    2016-01-28

    1. Objectives This project combines automated in situ observations of the isotopologues of CO2 with root observations, novel experimental manipulations of belowground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. aboveground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: A. Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics ; B. Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated belowground using measurements of root growth and indices of belowground autotrophic vs. heterotrophic respiration (via trenched plots and isotope measurements); C. Testing whether plant allocation of carbon belowground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and D. Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2). 2. Highlights Accomplishments: • Our isotopic eddy flux record has completed its 5th full year and has been used to independently estimate ecosystem-scale respiration and photosynthesis. • Soil surface chamber isotopic flux measurements were carried out during three growing seasons, in conjunction with a trenching manipulation. Key findings to date (listed by objective): A. Partitioning of Net Ecosystem Exchange: 1. Ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light (the “Kok effect”) at the ecosystem scale. 2. Because it neglects the Kok effect, the standard NEE partitioning approach overestimates ecosystem

  10. Unearthing belowground bud banks in fire-prone ecosystems.

    Science.gov (United States)

    Pausas, Juli G; Lamont, Byron B; Paula, Susana; Appezzato-da-Glória, Beatriz; Fidelis, Alessandra

    2018-03-01

    Despite long-time awareness of the importance of the location of buds in plant biology, research on belowground bud banks has been scant. Terms such as lignotuber, xylopodium and sobole, all referring to belowground bud-bearing structures, are used inconsistently in the literature. Because soil efficiently insulates meristems from the heat of fire, concealing buds below ground provides fitness benefits in fire-prone ecosystems. Thus, in these ecosystems, there is a remarkable diversity of bud-bearing structures. There are at least six locations where belowground buds are stored: roots, root crown, rhizomes, woody burls, fleshy swellings and belowground caudexes. These support many morphologically distinct organs. Given their history and function, these organs may be divided into three groups: those that originated in the early history of plants and that currently are widespread (bud-bearing roots and root crowns); those that also originated early and have spread mainly among ferns and monocots (nonwoody rhizomes and a wide range of fleshy underground swellings); and those that originated later in history and are strictly tied to fire-prone ecosystems (woody rhizomes, lignotubers and xylopodia). Recognizing the diversity of belowground bud banks is the starting point for understanding the many evolutionary pathways available for responding to severe recurrent disturbances. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  11. Estimating patterns in Spartina alterniflora belowground biomass within salt marshes

    Science.gov (United States)

    O'Connell, J. L.; Mishra, D. R.; Alber, M.; Byrd, K. B.

    2017-12-01

    Belowground biomass of marsh plants, such as Spartina alterniflora, help prevent marsh loss because they promote soil accretion, stabilize soils and add organic matter. However, site-wide estimates of belowground biomass are difficult to obtain because root:shoot ratios vary considerably both within species and across sites. We are working to develop a data fusion tool that can predict key characteristics of S. alterniflora, including belowground biomass and plant canopy N, based on satellite imagery. We used field observations from four salt marsh locations along the Georgia Coast, including one that is studied as part of the Georgia Coastal Ecosystems LTER project. From field and remote-sensing data, we developed a hybrid modeling approach to estimate % foliar N (a surrogate for plant assimilated nutrients). Partial Least squares (PLS) regression analysis of Landsat-8 spectral bands could predict variation in foliar N and belowground biomass, suggesting this public data source might be utilized for site-wide assessment of plant biophysical variables in salt marshes. Spectrally estimated foliar N and aboveground biomass were associated with belowground biomass and root:shoot ratio in S. alterniflora. This mirrors results from a previous study from the Sacramento-San Joaquin Delta, CA, on Scheonoplectus acutus, a marsh plant found in some tidal freshwater marshes. Therefore remote sensing may be a useful tool for measuring whole plant productivity among multiple coastal marsh species.

  12. Linking FRRF Derived Photophysiology with Carbon-based Primary Productivity: Insights from Concepts of Cellular Energy Allocation

    Science.gov (United States)

    Schuback, N.; Schallenberg, C.; Duckham, C.; Flecken, M.; Maldonado, M. T.; Tortell, P. D.

    2016-02-01

    Active chlorophyll a fluorescence approaches, including fast repetition rate fluorometry (FRRF), have the potential to provide estimates of phytoplankton primary productivity at unprecedented spatial and temporal resolution. FRRF-derived productivity rates are based on estimates of charge separation in photosystem II (ETRRCII), which must be converted into ecologically relevant units of carbon fixation. Understanding sources of variability in the coupling of ETRRCII and carbon fixation provides important physiological insight into phytoplankton photosynthesis, and is critical for the application of FRRF as a primary productivity measurement tool. We present data from a series of experiments during which we simultaneously measured phytoplankton carbon fixation and ETRRCII in the iron-limited NE subarctic Pacific. Our results show significant variability of the derived conversion factor (Ve:C/nPSII), with highest values observed under conditions of excess excitation pressure at the level of photosystem II, caused by high light and/or low iron. Our results will be discussed in the context of metabolic plasticity, which evolved in phytoplankton to simultaneously maximize growth and provide photoprotection under fluctuating light and limiting nutrient availabilities. Because the derived conversion factor is associated with conditions of excess light, it correlates with the expression of non-photochemical quenching (NPQ) in the pigment antenna, also derived from FRRF measurements. Our results demonstrate a significant correlation between NPQ and the conversion factor Ve:C/nPSII, and the potential of this relationship to improve FRRF-based estimates of phytoplankton carbon fixation rates is discussed.

  13. Exposure to an enriched CO2 atmosphere alters carbon assimilation and allocation in a pine forest ecosystem

    Science.gov (United States)

    Karina V.R. Schafer; Ram Oren; David S. Ellsworth; Chun-Ta Lai; Jeffrey D. Herricks; Adrien C. Finzi; Daniel D. Richter; Gabriel G. Katul

    2003-01-01

    We linked a leaf-level C02 assimilation model with a model that accounts for light attenuation in the canopy and measurements of sap-flux-based canopy conductance into a new canopy conductance-constrained carbon assimilation (4C-A) model. We estimated canopy C02 uptake (AnC) at...

  14. Maintainability allocation

    International Nuclear Information System (INIS)

    Guyot, Christian.

    1980-06-01

    The author gives the general lines of a method for the allocation and for the evaluation of maintainability of complex systems which is to be developed during the conference. The maintainability objective is supposed to be formulated under the form of a mean time to repair (M.T.T.R.) [fr

  15. [Carbon storage of forest vegetation and allocation for main forest types in the east of Da-xing'an Mountains based on additive biomass model].

    Science.gov (United States)

    Peng, Wei; Dong, Li Hu; Li, Feng Ri

    2016-12-01

    Based on the biomass investigation data of main forest types in the east of Daxing'an Mountains, the additive biomass models of 3 main tree species were developed and the changes of carbon storage and allocation of forest community of tree layer, shrub layer, herb layer and litter layer from different forest types were discussed. The results showed that the carbon storage of tree layer, shrub layer, herb layer and litter layer for Rhododendron dauricum-Larix gmelinii forest was 71.00, 0.34, 0.05 and 11.97 t·hm -2 , respectively. Similarly, the carbon storage of the four layers of Ledum palustre-L. gmelinii forest was 47.82, 0.88, 0, 5.04 t·hm -2 , 56.56, 0.44, 0.04, 8.72 t·hm -2 for R. dauricum-mixed forest of L. gmelinii-Betula platyphylla, 46.21, 0.66, 0.07, 6.16 t·hm -2 for L. palustre-mixed forest of L. gmelinii-B. platyphylla, 40.90, 1.37, 0.04, 3.67 t·hm -2 for R. dauricum-B. platyphylla forest, 36.28, 1.12, 0.18, 4.35 t·hm -2 for L. palustre-B. platyphylla forest. The carbon storage of forest community for the understory vegetation of R. dauricum was higher than that of the forest with L. palustre. In the condition of similar circumstances for the understory, the order of carbon storage for forest community was L. gmelinii forest > the mixed forest of L. gmelinii-B. platyphylla > B. platyphylla forest. The carbon storage of different forest types was different with the order of R. dauricum-L. gmelinii forest (83.36 t·hm -2 )> R. dauricum-mixed forest of L. gmelinii-B. platyphylla (65.76 t·hm -2 ) > L. palustre-L. gmelinii forest (53.74 t·hm -2 )> L. palustre-mixed forest of L. gmelinii-B. platyphylla (53.10 t·hm -2 )> R. dauricum-B. platyphylla forest (45.98 t·hm -2 ) > L. palustre-B. platyphylla forest (41.93 t·hm -2 ). The order of carbon storage for the vertical distribution in forest communities with diffe-rent forest types was the tree layer (85.2%-89.0%) > litter layer (8.0%-14.4%) > shrub layer (0.4%-2.7%) > herb layer (0-0.4%).

  16. Large grazers modify effects of aboveground-belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Geuverink, Elzemiek; Olff, Han; Schmid, Bernhard

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  17. Large grazers modify effects of aboveground–belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Geuverink, E.; Olff, H.

    2012-01-01

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  18. Tendances Carbone no. 106. Free allocation in the EU ETS by 2030: paving the way for decarbonization of industry

    International Nuclear Information System (INIS)

    Jalard, Matthieu; Alberola, Emilie; Dahan, Lara

    2015-10-01

    Among the publications of I4CE, 'Tendances Carbone' bulletin specifically studies the developments of the European market for CO 2 allowances. Beside some statistical figures about energy production/consumption and carbon markets, this issue specifically addresses the following points: - EU ETS - MSR: On September 18, EU Environment Ministers adopted the Market Stability Reserve (MSR) for a start date in 2018. - EU ETS - MSR: On September, the timeline for the revision of the Directive for Phase IV of the EU ETS was detailed. A vote in plenary is expected in November 2016. - Energy Union: On September 28, a European Council meeting on Energy published draft conclusions on the governance system of the Energy Union, based on National Energy and Climate Plans to be drawn up in 2018

  19. Exploring the Influence of Topography on Belowground C Processes Using a Coupled Hydrologic-Biogeochemical Model

    Science.gov (United States)

    Shi, Y.; Davis, K. J.; Eissenstat, D. M.; Kaye, J. P.; Duffy, C.; Yu, X.; He, Y.

    2014-12-01

    Belowground carbon processes are affected by soil moisture and soil temperature, but current biogeochemical models are 1-D and cannot resolve topographically driven hill-slope soil moisture patterns, and cannot simulate the nonlinear effects of soil moisture on carbon processes. Coupling spatially-distributed physically-based hydrologic models with biogeochemical models may yield significant improvements in the representation of topographic influence on belowground C processes. We will couple the Flux-PIHM model to the Biome-BGC (BBGC) model. Flux-PIHM is a coupled physically-based land surface hydrologic model, which incorporates a land-surface scheme into the Penn State Integrated Hydrologic Model (PIHM). The land surface scheme is adapted from the Noah land surface model. Because PIHM is capable of simulating lateral water flow and deep groundwater, Flux-PIHM is able to represent the link between groundwater and the surface energy balance, as well as the land surface heterogeneities caused by topography. The coupled Flux-PIHM-BBGC model will be tested at the Susquehanna/Shale Hills critical zone observatory (SSHCZO). The abundant observations, including eddy covariance fluxes, soil moisture, groundwater level, sap flux, stream discharge, litterfall, leaf area index, above ground carbon stock, and soil carbon efflux, make SSHCZO an ideal test bed for the coupled model. In the coupled model, each Flux-PIHM model grid will couple a BBGC cell. Flux-PIHM will provide BBGC with soil moisture and soil temperature information, while BBGC provides Flux-PIHM with leaf area index. Preliminary results show that when Biome- BGC is driven by PIHM simulated soil moisture pattern, the simulated soil carbon is clearly impacted by topography.

  20. UV-B-mediated changes on below-ground communities associated with the roots of Acer saccharum

    International Nuclear Information System (INIS)

    Klironomos, J.N.; Allen, M.F.

    1995-01-01

    1. Little is known about how exposure to UV-B radiation affects rhizosphere microbes. Rhizosphere organisms are fed primarily by root-derived substrates and fulfil functions such as mineralization, immobilization, decomposition, pathogeneity and improvement of plant nutrition; they form the base of the below-ground food web. 2. In this study, we exposed Sugar Maple (Acer saccharum) seedlings to UV-B radiation in order to determine if UV-B influences the activities of mycorrhizal and non-mycorrhizal fungi, bacteria and microbe-feeding arthropods in the rhizosphere. 3. Below-ground organisms are greatly affected by UV-B radiation. Overall, carbon-flow in the plant soil system was shifted from a mutualistic-closed, mycorrhizal-dominated system to an opportunist-open, saprobe/pathogen-dominated one. (author)

  1. Elevated CO{sub 2} does not ameliorate effects of ozone on carbon allocation in Pinus halepensis and Betula pendula in symbiosis with Paxillus involutus

    Energy Technology Data Exchange (ETDEWEB)

    Kytoeviita, M.M. [Oulu Univ., Dept. of Biology, Oulu (Finland); Pelloux, J.; Fontaine, V.; Botton, B.; Dizengremel, P. [Univ. Henri Poincare-Nancy, Lab. de Biologie Forestiere Associe INRA, Vandoeuvre-les-Nancy (France)

    1999-07-01

    The effect of 700 {mu}mol CO{sub 2} mol{sup -1}, 200 nmol ozone mol{sup -1} and a combination of the two on carbon allocation was examined in Pinus halepensis co-cultured with Betula pendula in symbiosis with the ectomycorrhizal fungus Paxillus involutus. The results show that under low nutrient and ozone levels, elevated CO{sub 2} has no effect on the growth of B. pendula or P. halepensis seedlings nor on net carbon partitioning between plant parts. Elevated CO{sub 2} did not enhance the growth of the fungus in symbiosis with the birch. On the other hand, ozone had a strong negative effect on the growth of the birch, which corresponded with the significantly reduced growth rates of the fungus. Exposure to elevated CO{sub 2} did not ameliorate the negative effects of ozone on birch; in contrast, it acted as an additional stress factor. Neither ozone nor CO{sub 2} had significant effects on biomass accumulation in the pine seedlings. Ozone stimulated the spread of mycorrhizal infection from the birch seedlings to neighbouring pines and had no statistically significant effects on phosphoenolpyruvate carboxylase (PEPC) or ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity in the pine needles or on PEPC activity in pine roots. (au)

  2. Influence of nutrient signals and carbon allocation on the expression of phosphate and nitrogen transporter genes in winter wheat (Triticum aestivum L.) roots colonized by arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Tian, Hui; Yuan, Xiaolei; Duan, Jianfeng; Li, Wenhu; Zhai, Bingnian; Gao, Yajun

    2017-01-01

    Arbuscular mycorrhizal (AM) colonization of plant roots causes the down-regulation of expression of phosphate (Pi) or nitrogen (N) transporter genes involved in direct nutrient uptake pathways. The mechanism of this effect remains unknown. In the present study, we sought to determine whether the expression of Pi or N transporter genes in roots of winter wheat colonized by AM fungus responded to (1) Pi or N nutrient signals transferred from the AM extra-radical hyphae, or (2) carbon allocation changes in the AM association. A three-compartment culture system, comprising a root compartment (RC), a root and AM hyphae compartment (RHC), and an AM hyphae compartment (HC), was used to test whether the expression of Pi or N transporter genes responded to nutrients (Pi, NH4+ and NO3-) added only to the HC. Different AM inoculation density treatments (roots were inoculated with 0, 20, 50 and 200 g AM inoculum) and light regime treatments (6 hours light and 18 hours light) were established to test the effects of carbon allocation on the expression of Pi or N transporter genes in wheat roots. The expression of two Pi transporter genes (TaPT4 and TaPHT1.2), five nitrate transporter genes (TaNRT1.1, TaNRT1.2, TaNRT2.1, TaNRT2.2, and TaNRT2.3), and an ammonium transporter gene (TaAMT1.2) was quantified using real-time polymerase chain reaction. The expression of TaPT4, TaNRT2.2, and TaAMT1.2 was down-regulated by AM colonization only when roots of host plants received Pi or N nutrient signals. However, the expression of TaPHT1.2, TaNRT2.1, and TaNRT2.3 was down-regulated by AM colonization, regardless of whether there was nutrient transfer from AM hyphae. The expression of TaNRT1.2 was also down-regulated by AM colonization even when there was no nutrient transfer from AM hyphae. The present study showed that an increase in carbon consumption by the AM fungi did not necessarily result in greater down-regulation of expression of Pi or N transporter genes.

  3. Plant life history and above–belowground interactions

    NARCIS (Netherlands)

    Deyn, de Gerlinde

    2017-01-01

    The importance of above–belowground interactions for plant growth and community dynamics became clear in the last decades, whereas the numerous studies on plant life history improved our knowledge on eco-evolutionary dynamics. However, surprisingly few studies have linked both research fields

  4. Reproductive allocation in plants as affected by elevated carbon dioxide and other environmental changes: a synthesis using meta-analysis and graphical vector analysis.

    Science.gov (United States)

    Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M

    2015-04-01

    Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future.

  5. Carbon and nitrogen balances for six shrublands across Europe

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  6. Above- and belowground linkages in Sphagnum peatland: climate warming affects plant-microbial interactions.

    Science.gov (United States)

    Jassey, Vincent E J; Chiapusio, Geneviève; Binet, Philippe; Buttler, Alexandre; Laggoun-Défarge, Fatima; Delarue, Frédéric; Bernard, Nadine; Mitchell, Edward A D; Toussaint, Marie-Laure; Francez, André-Jean; Gilbert, Daniel

    2013-03-01

    Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top-predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum-polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above- and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands. © 2012 Blackwell Publishing Ltd.

  7. Early and late seasonal carbon sequestration and allocation in larch trees growing on permafrost in Central Siberia

    Science.gov (United States)

    Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

    2014-05-01

    Despite large geographic extent of deciduous conifer species Larix gmelinii, its seasonal photosynthetic activity and translocation of photoassimilated carbon within a tree remain poorly studied. To get better insight into productivity of larch trees growing on permafrost soils in Siberian larch biome we aimed to analyze dynamics of foliage parameters (i.e. leaf area, biomass, %N, %P etc.), seasonal dynamics of photosynthetic activity and apply whole tree labeling by 13CO2, which is powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree (Kagawa et al., 2006; Keel et al., 2012). Experimental plot has been established in mature 105 year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64o17'13" N, 100o11'55" E, 148 m a.s.l.). Trees selected for experiments represented mean tree of the stand. Measurements of seasonal photosynthetic activity and foliar biomass sampling were arranged from early growing season (June 8, 2013) until yellowing and senescence of needles on September 17, 2013. Labeling by 13C in whole tree chamber was conducted by three pulses ([CO2]max ≤ 2,500 ppmv, 13CO2 (30% v/v)) at the early (June) and late (August) phase of growing season for different trees in 3 replicates each time. Both early season and late season labeling experiments demonstrated high rate of 13CO2 assimilation and respective enrichment of needle tissues by 13C: δ13C increased from -28.7 up to +670‰ just after labeling. However, there was distinct post-labeling dynamics of needle δ13C among two seasonal experiments. At the early season 13C depletion in labeled needles was slower, and δ13C approached after 40 days ca. +110 ‰ and remained constant till senescence. In the late season (August) needles were losing labeled C with much faster rate and approached only +1.5 ‰ upon senescence (28 days exposition). These findings suggest that in early season ca. 20% of

  8. Long-term effects of elevated carbon dioxide concentration and provenance on four clones of Sitka spruce (Picea sitchensis). I. Plant growth, allocation and ontogeny

    Energy Technology Data Exchange (ETDEWEB)

    Centritto, M. [Inst. di Biochimica ed Ecofisiologia Vegetale, Rome (Italy); Lee, H.S.J.; Jarvis, P.G. [Univ. Edinburgh, Inst. of Ecology and Resource Management, Edinburgh (United Kingdom)

    1999-09-01

    An investigation was carried out to determine the effects of elevated CO(2) concentration on the long-term growth and carbon allocation of four clones of Sitka spruce taken from two provenances under conditions of non-limiting water and nutrient supply. The use of clones from different provenances provided a unique way of examining effects of elevated CO(2) concentration on competitiveness of saplings adapted to climates with different temperature and day length. The saplings were fertilized following the Ingestad approach to yield a supply of mineral nutrients at free access in order to maintain nutrient uptake proportional to plant growth, and rule out undefined variability in sink strength that might have been caused by water and nutrient deficiencies. There was considerable variation in growth responses among clones. Across all four clones there was a 40% increase in total dry mass of the saplings growth in elevated CO(2) concentration, but the genetic differences in the growth response to elevated CO(2) concentration were significant. The clones originated from different latitudinal provenances, and were acclimated to different temperatures and day length climates, and so had different abilities to acclimate to their new environment. Some Sitka spruce clones may grow better in lowland Scotland as climate change occurs. Genetic differences in the growth response to elevated CO(2) concentration may be exploited through the assessment of nursery stock for future forest planning. 33 refs., 5 figs.

  9. Relocation of carbon from decomposition of {sup 14}C-labelled needle and fine root litter in peat soil

    Energy Technology Data Exchange (ETDEWEB)

    Domish, T; Laine, J; Laiho, R [Helsinki Univ. (Finland). Dept. of Forest Ecology; Finer, L [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Karsisto, M [Finnish Forest Research Inst. (Finland). Dept. of Forest Ecology

    1997-12-31

    Drainage of peatlands promotes a shift of biomass and production from the ground vegetation to the trees. Thus, the above-ground (e.g. needles) and below-ground (roots) litter production of trees increases. Fine roots in particular are an important factor in the carbon and nutrient cycle in forest ecosystems. A major part of the annual net primary production of trees may be allocated below ground, the relative proportion being smaller on fertile sites than on less fertile ones. For modelling the carbon balance of drained peatlands, it is important to know the fate of carbon from newly introduced and decomposing litter. Newly added and fertilised tree litter material may be decomposed at a rate different than litter from the ground vegetation. The objectives of this study are to study the pathways of decomposing litter carbon in peat soil and to evaluate the use of the litterbag method in a controlled environment. (9 refs.)

  10. Relocation of carbon from decomposition of {sup 14}C-labelled needle and fine root litter in peat soil

    Energy Technology Data Exchange (ETDEWEB)

    Domish, T.; Laine, J.; Laiho, R. [Helsinki Univ. (Finland). Dept. of Forest Ecology; Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Karsisto, M. [Finnish Forest Research Inst. (Finland). Dept. of Forest Ecology

    1996-12-31

    Drainage of peatlands promotes a shift of biomass and production from the ground vegetation to the trees. Thus, the above-ground (e.g. needles) and below-ground (roots) litter production of trees increases. Fine roots in particular are an important factor in the carbon and nutrient cycle in forest ecosystems. A major part of the annual net primary production of trees may be allocated below ground, the relative proportion being smaller on fertile sites than on less fertile ones. For modelling the carbon balance of drained peatlands, it is important to know the fate of carbon from newly introduced and decomposing litter. Newly added and fertilised tree litter material may be decomposed at a rate different than litter from the ground vegetation. The objectives of this study are to study the pathways of decomposing litter carbon in peat soil and to evaluate the use of the litterbag method in a controlled environment. (9 refs.)

  11. How drought severity constrains GPP and its partitioning among carbon pools in a Quercus ilex coppice?

    Science.gov (United States)

    Rambal, S.; Lempereur, M.; Limousin, J. M.; Martin-StPaul, N. K.; Ourcival, J. M.; Rodríguez-Calcerrada, J.

    2014-06-01

    The partitioning of photosynthates toward biomass compartments has a crucial role in the carbon sink function of forests. Few studies have examined how carbon is allocated toward plant compartments in drought prone forests. We analyzed the fate of GPP in relation to yearly water deficit in an old evergreen Mediterranean Quercus ilex coppice severely affected by water limitations. Gross and net carbon fluxes between the ecosystem and the atmosphere were measured with an eddy-covariance flux tower running continuously since 2001. Discrete measurements of litterfall, stem growth and fAPAR allowed us to derive annual productions of leaves, wood, flowers and acorns and an isometric relationship between stem and belowground biomass has been used to estimate perennial belowground growth. By combining eddy-covariance fluxes with annual productions we managed to close a C budget and derive values of autotrophic and heterotrophic respirations, NPP and carbon use efficiency (CUE, the ratio between NPP and GPP). Average values of yearly NEP, GPP and Reco were 282, 1259 and 977 g C m-2. The corresponding ANPP components were 142.5, 26.4 and 69.6 g C m-2 for leaves, reproductive effort (flowers and fruits) and stems. Gross and net carbon exchange between the ecosystem and the atmosphere were affected by annual water deficit. Partitioning to the different plant compartments was also impacted by drought, with a hierarchy of responses going from the most affected, the stem growth, to the least affected, the leaf production. The average CUE was 0.40, which is well in the range for Mediterranean-type forest ecosystems. CUE tended to decrease more slightly in response to drought than GPP and NPP, probably due to drought-acclimation of autotrophic respiration. Overall, our results provide a baseline for modeling the inter-annual variations of carbon fluxes and allocation in this widespread Mediterranean ecosystem and highlight the value of maintaining continuous experimental

  12. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Science.gov (United States)

    Smith, Maria S; Fridley, Jason D; Goebel, Marc; Bauerle, Taryn L

    2014-01-01

    Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  13. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    Full Text Available Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native versus L. sempervirens (native and Frangula alnus (non-native versus Rhamnus alnifolia (native, over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  14. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

    International Nuclear Information System (INIS)

    Jones, M.L.M.; Hodges, G.; Mills, G.

    2010-01-01

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

  15. C3 and C4 biomass allocation responses to elevated CO2 and nitrogen: contrasting resource capture strategies

    Science.gov (United States)

    White, K.P.; Langley, J.A.; Cahoon, D.R.; Megonigal, J.P.

    2012-01-01

    Plants alter biomass allocation to optimize resource capture. Plant strategy for resource capture may have important implications in intertidal marshes, where soil nitrogen (N) levels and atmospheric carbon dioxide (CO2) are changing. We conducted a factorial manipulation of atmospheric CO2 (ambient and ambient + 340 ppm) and soil N (ambient and ambient + 25 g m-2 year-1) in an intertidal marsh composed of common North Atlantic C3 and C4 species. Estimation of C3 stem turnover was used to adjust aboveground C3 productivity, and fine root productivity was partitioned into C3-C4 functional groups by isotopic analysis. The results suggest that the plants follow resource capture theory. The C3 species increased aboveground productivity under the added N and elevated CO2 treatment (P 2 alone. C3 fine root production decreased with added N (P 2 (P = 0.0481). The C4 species increased growth under high N availability both above- and belowground, but that stimulation was diminished under elevated CO2. The results suggest that the marsh vegetation allocates biomass according to resource capture at the individual plant level rather than for optimal ecosystem viability in regards to biomass influence over the processes that maintain soil surface elevation in equilibrium with sea level.

  16. Residency Allocation Database

    Data.gov (United States)

    Department of Veterans Affairs — The Residency Allocation Database is used to determine allocation of funds for residency programs offered by Veterans Affairs Medical Centers (VAMCs). Information...

  17. Empirical and theoretical challenges in aboveground-belowground ecology

    DEFF Research Database (Denmark)

    W.H. van der Putten,; R.D. Bardgett; P.C. de Ruiter

    2009-01-01

    of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects...... and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground-belowground approach offers perspectives for enhancing ecological understanding, namely...

  18. Costs of jasmonic acid induced defense in aboveground and belowground parts of corn (Zea mays L.).

    Science.gov (United States)

    Feng, Yuanjiao; Wang, Jianwu; Luo, Shiming; Fan, Huizhi; Jin, Qiong

    2012-08-01

    Costs of jasmonic acid (JA) induced plant defense have gained increasing attention. In this study, JA was applied continuously to the aboveground (AG) or belowground (BG) parts, or AG plus BG parts of corn (Zea mays L.) to investigate whether JA exposure in one part of the plant would affect defense responses in another part, and whether or not JA induced defense would incur allocation costs. The results indicated that continuous JA application to AG parts systemically affected the quantities of defense chemicals in the roots, and vice versa. Quantities of DIMBOA and total amounts of phenolic compounds in leaves or roots generally increased 2 or 4 wk after the JA treatment to different plant parts. In the first 2 wk after application, the increase of defense chemicals in leaves and roots was accompanied by a significant decrease of root length, root surface area, and root biomass. Four weeks after the JA application, however, no such costs for the increase of defense chemicals in leaves and roots were detected. Instead, shoot biomass and root biomass increased. The results suggest that JA as a defense signal can be transferred from AG parts to BG parts of corn, and vice versa. Costs for induced defense elicited by continuous JA application were found in the early 2 wk, while distinct benefits were observed later, i.e., 4 wk after JA treatment.

  19. Mapping the above and belowground biomass in three landscapes in Cameroon, Rwanda and DRC: pilot cases in REDD+ pilot project.

    Science.gov (United States)

    Sufo Kankeu, R.

    2017-12-01

    A number of biomass/carbon maps have been recently produced using different approaches and despite their comparison there is still a gap. To fill this gap there is a need to provide accurate maps based on the field data on all types of land use and land cover. Based on the field data from plots established in three pilot projects around Virunga National park in Rwanda, Tri-national Sangha landscape in Cameroon and lac Télé-Lac Tumba landscape in DRC, this paper intend to analyse the relationship between land use change and biomass and present the variability through biomass/carbon maps. The above and belowground biomass was calculated from 95 nested plots of 20 meters radius. The value of biomass/carbon per plot were thus used to elaborate carbon maps of each study site. In the same the way the correlation between the land use and underground and above ground carbon stock were analysed using geographically weighted regression. These data have been joint with classified Spot 5 image and aggregated to come out will acceptable result. Results show that there is a strong relationship between land use in various project sites and the carbon stock related, the change of a forest cover directly impact on carbon stock/biomass.in the same way carbon map realized base on field data and IDW, Kriging or spline module show an idea on the carbon distribution but the maps are not accurate giving the distance between plots,

  20. Foliar uptake of fog water and transport belowground alleviates drought effects in the cloud forest tree species, Drimys brasiliensis (Winteraceae).

    Science.gov (United States)

    Eller, Cleiton B; Lima, Aline L; Oliveira, Rafael S

    2013-07-01

    Foliar water uptake (FWU) is a common water acquisition mechanism for plants inhabiting temperate fog-affected ecosystems, but the prevalence and consequences of this process for the water and carbon balance of tropical cloud forest species are unknown. We performed a series of experiments under field and glasshouse conditions using a combination of methods (sap flow, fluorescent apoplastic tracers and stable isotopes) to trace fog water movement from foliage to belowground components of Drimys brasiliensis. In addition, we measured leaf water potential, leaf gas exchange, leaf water repellency and growth of plants under contrasting soil water availabilities and fog exposure in glasshouse experiments to evaluate FWU effects on the water and carbon balance of D. brasiliensis saplings. Fog water diffused directly through leaf cuticles and contributed up to 42% of total foliar water content. FWU caused reversals in sap flow in stems and roots of up to 26% of daily maximum transpiration. Fog water transported through the xylem reached belowground pools and enhanced leaf water potential, photosynthesis, stomatal conductance and growth relative to plants sheltered from fog. Foliar uptake of fog water is an important water acquisition mechanism that can mitigate the deleterious effects of soil water deficits for D. brasiliensis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  1. Dynamic Allocation of Sugars in Barley

    Science.gov (United States)

    Cumberbatch, L. C.; Crowell, A. S.; Fallin, B. A.; Howell, C. R.; Reid, C. D.; Weisenberger, A. G.; Lee, S. J.; McKisson, J. E.

    2014-03-01

    Allocation of carbon and nitrogen is a key factor for plant productivity. Measurements are carried out by tracing 11C-tagged sugars using positron emission tomography and coincidence counting. We study the mechanisms of carbon allocation and transport from carbohydrate sources (leaves) to sinks (stem, shoot, roots) under various environmental conditions such as soil nutrient levels and atmospheric CO2 concentration. The data are analyzed using a transfer function analysis technique to model transport and allocation in barley plants. The experimental technique will be described and preliminary results presented. This work was supported in part by USDOE Grant No. DE-FG02-97-ER41033 and DE-SC0005057.

  2. Morchella tomentosa: a unique belowground structure and a new clade of morels

    Science.gov (United States)

    Franck O.P. Stefani; Serge Sokolski; Trish L. Wurtz; Yves Piché; Richard C. Hamelin; J. André Fortin; Jean A. Bérubé

    2010-01-01

    Mechanisms involved in post-fire morel fructification remain unclear. A new undescribed belowground vegetative structure of Marchella tomentosa in a burned boreal forest was investigated north of Fairbanks, Alaska. The name "radiscisclerotium" is proposed to define this peculiar and elaborate belowground vegetative structure of ...

  3. Use of belowground growing degree days to predict rooting of dormant hardwood cuttings of Populus

    Science.gov (United States)

    R.S., Jr. Zalesny; E.O. Bauer; D.E. Riemenschneider

    2004-01-01

    Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones,...

  4. Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

    Science.gov (United States)

    Warren D. Devine; Timothy B. Harrington

    2009-01-01

    We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

  5. Transport Infrastructure Slot Allocation

    NARCIS (Netherlands)

    Koolstra, K.

    2005-01-01

    In this thesis, transport infrastructure slot allocation has been studied, focusing on selection slot allocation, i.e. on longer-term slot allocation decisions determining the traffic patterns served by infrastructure bottlenecks, rather than timetable-related slot allocation problems. The

  6. Interactions between above- and belowground organisms modified in climate change experiments

    DEFF Research Database (Denmark)

    Stevnsbak, Karen; Scherber, Christoph; Gladbach, David

    2012-01-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate4 can be expected to influence above–belowground interactions. Here, we use...... a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms.We use an insect herbivore...... a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground–belowground interactions through changes in nutrient availability....

  7. How drought severity constrains gross primary production(GPP) and its partitioning among carbon pools in a Quercus ilex coppice?

    Science.gov (United States)

    Rambal, S.; Lempereur, M.; Limousin, J. M.; Martin-StPaul, N. K.; Ourcival, J. M.; Rodríguez-Calcerrada, J.

    2014-12-01

    The partitioning of photosynthates toward biomass compartments plays a crucial role in the carbon (C) sink function of forests. Few studies have examined how carbon is allocated toward plant compartments in drought-prone forests. We analyzed the fate of gross primary production (GPP) in relation to yearly water deficit in an old evergreen Mediterranean Quercus ilex coppice severely affected by water limitations. Carbon fluxes between the ecosystem and the atmosphere were measured with an eddy covariance flux tower running continuously since 2001. Discrete measurements of litterfall, stem growth and fAPAR allowed us to derive annual productions of leaves, wood, flowers and acorns, and an isometric relationship between stem and belowground biomass has been used to estimate perennial belowground growth. By combining eddy covariance fluxes with annual net primary productions (NPP), we managed to close a C budget and derive values of autotrophic, heterotrophic respirations and carbon-use efficiency (CUE; the ratio between NPP and GPP). Average values of yearly net ecosystem production (NEP), GPP and Reco were 282, 1259 and 977 g C m-2. The corresponding aboveground net primary production (ANPP) components were 142.5, 26.4 and 69.6 g C m-2 for leaves, reproductive effort (flowers and fruits) and stems, respectively. NEP, GPP and Reco were affected by annual water deficit. Partitioning to the different plant compartments was also impacted by drought, with a hierarchy of responses going from the most affected - the stem growth - to the least affected - the leaf production. The average CUE was 0.40, which is well in the range for Mediterranean-type forest ecosystems. CUE tended to decrease less drastically in response to drought than GPP and NPP did, probably due to drought acclimation of autotrophic respiration. Overall, our results provide a baseline for modeling the inter-annual variations of carbon fluxes and allocation in this widespread Mediterranean ecosystem, and

  8. Above- and below-ground responses of Calamagrostis purpurea to UV-B radiation and elevated CO{sub 2} under phosphorus limitation

    Energy Technology Data Exchange (ETDEWEB)

    Bussell, J.S.; Gwynn-Jones, D.; Griffith, G.W.; Scullion, J. (Aberystwyth Univ., IBERS, Wales (United Kingdom))

    2012-08-15

    UV-B radiation and elevated CO{sub 2} may impact rhizosphere processes through altered below-ground plant resource allocation and root exudation, changes that may have implications for nutrient acquisition. As nutrients limit plant growth in many habitats, their supply may dictate plant response under elevated CO{sub 2}. This study investigated UV-B exposure and elevated CO{sub 2} effects, including interactions, on plant growth, tissue chemistry and rooting responses relating to P acquisition. The sub-arctic grass Calamagrostis purpurea was subjected to UV-B (0 or 3.04 kJ m-2day-1) and CO{sub 2} (ambient 380 or 650 ppmv) treatments in a factorial glasshouse experiment, with sparingly soluble P (0 or 0.152 mg P per plant as FePO{sub 4}) a further factor. It was hypothesized that UV-B exposure and elevated CO{sub 2} would change plant resource allocation, with CO{sub 2} mitigating adverse responses to UV-B exposure and aiding P uptake. Plant biomass and morphology, tissue composition and rhizosphere leachate properties were measured. UV-B directly affected chemical composition of shoots and interacted with CO{sub 2} to give a greater root biomass. Elevated CO{sub 2} altered the composition of both shoots and roots and increased shoot biomass and secondary root length, while leachate pH decreased. Below-ground responses to CO{sub 2} did not affect P acquisition although P limitation progressively reduced leachate pH and increased secondary root length. Although direct plant growth, foliar composition and below-ground nutrient acquisition responses were dominated by CO{sub 2} treatments, UV-B modified these CO{sub 2} responses significantly. These interactions have implications for plant responses to future atmospheric conditions. (Author)

  9. Carbon allocation and decomposition of root-derived organic matter in a plant-soil system of Calluna vulgaris as affected by elevated CO2.

    NARCIS (Netherlands)

    Verburg, P.S.J.; Gorissenand, A.; Arp, W.J.

    1998-01-01

    The effect of elevated CO2 on C allocation in plant and soil was assessed using soil cores planted with 1-y-old heather (Calluna vulgaris (L.) Hull). Plants were pulse-labeled with 14CO2 at ambient and elevated CO2 and two nitrogen regimes (low and high). After harvesting the plants, the soil was

  10. Carbon transfer from photosynthesis to below ground fine root/hyphae respiration in Quercus serrata using stable carbon isotope pulse labeling

    Science.gov (United States)

    Dannoura, M.; Kominami, Y.; Takanashi, S.; Takahashi, K.

    2013-12-01

    Studying carbon allocation in trees is a key to better understand belowground carbon cycle and its response to climate change. Tracing 13C in tree and soil compartments after pulse labeling is one of powerful tool to study the fate of carbon in forest ecosystems. This experiment was conducted in Yamashiro experimental forest, Kyoto, Japan. Annual mean temperature and precipitation from 1994 to 2009 are 15.5 ° C and 1,388 mm respectively. The branch pulse labeling were done 7 times in 2011 using same branch of Quercus serrata (H:11.7 m, DBH; 33.7 cm) to see seasonal variations of carbon velocity. Whole crown labeling of Quercus serrata (H:9 m, DBH; 13.7 cm) was done in 2012 to study carbon allocation and to especially focus on belowground carbon flux until to the hyphae respiration. Pure 13CO2 (99.9%) was injected to the labeling chamber which was set to branch or crown. Then, after one hour of branch labeling and 3.5 hour for crown labeling, the chamber was opened. Trunk respiration chambers, fine root chambers and hyphae chambers were set to the target tree to trace labeled carbon in the CO2 efflux. 41 μm mesh was used to exclude ingrowth of roots into hyphae chambers. The results show that the velocity of carbon through the tree varied seasonally, with higher velocity in summer than autumn, averaging 0.47 m h-1. Half-lives of labeled carbon in autotrophic respiration were similar above and below ground during the growing season, but they were twice longer in trunk than in root in autumn. From the whole crown labeling done end of growing season, the 13CO2 signal was observed 25 hours after labeling in trunk chamber and 34-37.7 hours after labeling in fine root and hyphae respiration almost simultaneously. Half-lives of 13 was longer in trunk than below ground. Trunk respiration was still using labelled carbon during winter suggesting that winter trunk respiration is partly fueled by carbon stored in the trunk at the end of the growing season.

  11. Long-term variation in above and belowground plant inputs alters soil organic matter biogeochemistry at the molecular-level

    Science.gov (United States)

    Simpson, M. J.; Pisani, O.; Lin, L.; Lun, O.; Simpson, A.; Lajtha, K.; Nadelhoffer, K. J.

    2015-12-01

    The long-term fate of soil carbon reserves with global environmental change remains uncertain. Shifts in moisture, altered nutrient cycles, species composition, or rising temperatures may alter the proportions of above and belowground biomass entering soil. However, it is unclear how long-term changes in plant inputs may alter the composition of soil organic matter (SOM) and soil carbon storage. Advanced molecular techniques were used to assess SOM composition in mineral soil horizons (0-10 cm) after 20 years of Detrital Input and Removal Treatment (DIRT) at the Harvard Forest. SOM biomarkers (solvent extraction, base hydrolysis and cupric (II) oxide oxidation) and both solid-state and solution-state nuclear magnetic resonance (NMR) spectroscopy were used to identify changes in SOM composition and stage of degradation. Microbial activity and community composition were assessed using phospholipid fatty acid (PLFA) analysis. Doubling aboveground litter inputs decreased soil carbon content, increased the degradation of labile SOM and enhanced the sequestration of aliphatic compounds in soil. The exclusion of belowground inputs (No roots and No inputs) resulted in a decrease in root-derived components and enhanced the degradation of leaf-derived aliphatic structures (cutin). Cutin-derived SOM has been hypothesized to be recalcitrant but our results show that even this complex biopolymer is susceptible to degradation when inputs entering soil are altered. The PLFA data indicate that changes in soil microbial community structure favored the accelerated processing of specific SOM components with littler manipulation. These results collectively reveal that the quantity and quality of plant litter inputs alters the molecular-level composition of SOM and in some cases, enhances the degradation of recalcitrant SOM. Our study also suggests that increased litterfall is unlikely to enhance soil carbon storage over the long-term in temperate forests.

  12. Short-Term Belowground Responses to Thinning and Burning Treatments in Southwestern Ponderosa Pine Forests of the USA

    Directory of Open Access Journals (Sweden)

    Steven T. Overby

    2016-02-01

    Full Text Available Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important belowground components before and after management-applied fuel treatments of thinning alone, thinning combined with prescribed fire, and prescribed fire in ponderosa pine (Pinus ponderosa stands at the Southwest Plateau, Fire and Fire Surrogate site, Arizona. Fuel treatments did not alter pH, total carbon and nitrogen (N concentrations, or base cations of the forest floor (O horizon or mineral soil (0–5 cm during this 2-year study. In situ rates of net N mineralization and nitrification in the surface mineral soil (0–15 cm increased 6 months after thinning with prescribed fire treatments; thinning only resulted in net N immobilization. The rates returned to pre-treatment levels after one year. Based on phospholipid fatty acid composition, microbial communities in treated areas were similar to untreated areas (control in the surface organic horizon and mineral soil (0–5 cm after treatments. Soil potential enzyme activities were not significantly altered by any of the three fuel treatments. Our results suggest that a variety of one-time alternative fuel treatments can reduce fire hazard without degrading soil fertility.

  13. The Effects of Nitrogen Addition on the Uptake and Allocation of Macro- and Micronutrients in Bothriochloa ischaemum on Loess Plateau in China

    Directory of Open Access Journals (Sweden)

    Zemin Ai

    2017-08-01

    Full Text Available The effects of nitrogen (N addition on the macro- and micronutrient concentrations, storage, and allocation of Bothriochloa ischaemum (L. Keng, a native forage plant on the Loess Plateau in China remain unclear. We studied the effects of N addition at 0 (CK, 2.5 (N1, 5.0 (N2, and 10.0 (N3 g N m-2 y-1. N addition significantly decreased the available copper (Cu, zinc (Zn, and total Cu concentration, but significantly increased the available iron concentration in the soil. Cu, manganese (Mn, and sodium (Na concentrations in aboveground tissues and potassium (K, magnesium, and Zn concentrations in belowground tissues significantly increased with N addition. Calcium (Ca concentrations in belowground tissues decreased significantly. The ratios of above- to belowground Ca, Cu, Zn, and Mn significantly increased with N addition. The maximum ratios appeared at N2 for Cu, Zn, and Mn. The aboveground, belowground, and total biomass storage of studied nutrients significantly changed with N addition, and most attained maximum values under N2 treatment. The storage ratios of above- to belowground Cu, Zn, Mn, and Na attained maximum values at N2. We conclude that N addition significantly, but differentially influence the macro- and micronutrient concentrations and storage in B. ischaemum. B. ischaemum allocated and accumulated increased macro- and micronutrients to its aboveground tissues and exhibited high total storage when the amount of N addition reached 5 g N m-2 y-1.

  14. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta Forests.

    Directory of Open Access Journals (Sweden)

    Anne C S McIntosh

    Full Text Available Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs and multiple carbon-source substrate-induced respiration (MSIR of the forest floor microbial community environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis showed that two above-ground (mean tree diameter, litter cover and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs properties were associated with variation in understory plant community composition. These results provide

  15. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests.

    Science.gov (United States)

    McIntosh, Anne C S; Macdonald, S Ellen; Quideau, Sylvie A

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  16. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests

    Science.gov (United States)

    McIntosh, Anne C. S.; Macdonald, S. Ellen; Quideau, Sylvie A.

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  17. Plant functional traits and soil carbon sequestration in contrasting biomes.

    NARCIS (Netherlands)

    De Deyn, G.B.; Cornelissen, J.H.C.; Bardgett, R.D.

    2008-01-01

    Plant functional traits control a variety of terrestrial ecosystem processes, including soil carbon storage which is a key component of the global carbon cycle. Plant traits regulate net soil carbon storage by controlling carbon assimilation, its transfer and storage in belowground biomass, and its

  18. Does carbon availability control temporal dynamics of radial growth in Norway spruce (Picea abies)?

    Science.gov (United States)

    Oberhuber, Walter; Gruber, Andreas; Swidrak, Irene

    2015-04-01

    Intra-annual dynamics of cambial activity and wood formation of coniferous species exposed to soil dryness revealed early culmination of maximum growth in late spring prior to occurrence of more favourable environmental conditions, i.e., repeated high rainfall events during summer (Oberhuber et al. 2014). Because it is well known that plants can adjust carbon allocation patterns to optimize resource uptake under prevailing environmental constraints, we hypothesize that early decrease in radial stem growth is an adaptation to cope with drought stress, which might require an early switch of carbon allocation to belowground organs. Physical blockage of carbon transport in the phloem through girdling causes accumulation and depletion of carbohydrates above and below the girdle, respectively, making this method quite appropriate to investigate carbon relationships in trees. Hence, in a common garden experiment we will manipulate the carbon status of Norway spruce (Picea abies) saplings by phloem blockage at different phenological stages during the growing season. We will present the methodological approach and first results of the study aiming to test the hypothesis that carbon status of the tree affects temporal dynamics of cambial activity and wood formation in conifers under drought. Acknowledgment The research is funded by the Austrian Science Fund (FWF): P25643-B16 "Carbon allocation and growth of Scots pine". Reference Oberhuber W, A Gruber, W Kofler, I Swidrak (2014) Radial stem growth in response to microclimate and soil moisture in a drought-prone mixed coniferous forest at an inner Alpine site. Eur J For Res 133:467-479.

  19. Seasonal/Interannual Variations of Carbon Sequestration and Carbon Emission in a Warm-Season Perennial Grassland

    OpenAIRE

    Deepa Dhital; Tomoharu Inoue; Hiroshi Koizumi

    2014-01-01

    Carbon sequestration and carbon emission are processes of ecosystem carbon cycling that can be affected while land area converted to grassland resulting in increased soil carbon storage and below-ground respiration. Discerning the importance of carbon cycle in grassland, we aimed to estimate carbon sequestration in photosynthesis and carbon emission in respiration from soil, root, and microbes, for four consecutive years (2007–2010) in a warm-season perennial grassland, Japan. Soil carbon emi...

  20. Quantifying carbon sequestration in forest plantations by modeling the dynamics of above and below ground carbon pools

    Science.gov (United States)

    Chris A. Maier; Kurt H. Johnsen

    2010-01-01

    Intensive pine plantation management may provide opportunities to increase carbon sequestration in the Southeastern United States. Developing management options that increase fiber production and soil carbon sequestration require an understanding of the biological and edaphic processes that control soil carbon turnover. Belowground carbon resides primarily in three...

  1. Early root overproduction not triggered by nutrients decisive for competitive success belowground

    NARCIS (Netherlands)

    Padilla, F.M.; Mommer, L.; Caluwe, de H.; Smit-Tiekstra, A.E.; Wagemaker, C.A.M.; Ouborg, N.J.; Kroon, de H.

    2013-01-01

    Background - Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information

  2. Rising Mean Annual Temperature Increases Carbon Flux and Alters Partitioning, but Does Not Change Ecosystem Carbon Storage in Hawaiian Tropical Montane Wet Forest

    Science.gov (United States)

    Litton, C. M.; Giardina, C. P.; Selmants, P.

    2014-12-01

    Terrestrial ecosystem carbon (C) storage exceeds that in the atmosphere by a factor of four, and represents a dynamic balance among C input, allocation, and loss. This balance is likely being altered by climate change, but the response of terrestrial C cycling to warming remains poorly quantified, particularly in tropical forests which play a disproportionately large role in the global C cycle. Over the past five years, we have quantified above- and belowground C pools and fluxes in nine permanent plots spanning a 5.2°C mean annual temperature (MAT) gradient (13-18.2°C) in Hawaiian tropical montane wet forest. This elevation gradient is unique in that substrate type and age, soil type, soil water balance, canopy vegetation, and disturbance history are constant, allowing us to isolate the impact of long-term, whole ecosystem warming on C input, allocation, loss and storage. Across the gradient, soil respiration, litterfall, litter decomposition, total belowground C flux, aboveground net primary productivity, and estimates of gross primary production (GPP) all increase linearly and positively with MAT. Carbon partitioning is dynamic, shifting from below- to aboveground with warming, likely in response to a warming-induced increase in the cycling and availability of soil nutrients. In contrast to observed patterns in C flux, live biomass C, soil C, and total ecosystem C pools remained remarkably constant with MAT. There was also no difference in soil bacterial taxon richness, phylogenetic diversity, or community composition with MAT. Taken together these results indicate that in tropical montane wet forests, increased temperatures in the absence of water limitation or disturbance will accelerate C cycling, will not alter ecosystem C storage, and will shift the products of photosynthesis from below- to aboveground. These results agree with an increasing number of studies, and collectively provide a unique insight into anticipated warming-induced changes in tropical

  3. Allometry and partitioning of above- and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes

    International Nuclear Information System (INIS)

    Kuyah, Shem; Dietz, Johannes; Muthuri, Catherine; Noordwijk, Meine van; Neufeldt, Henry

    2013-01-01

    Farmers in developing countries are one of the world's largest and most efficient producers of sequestered carbon. However, measuring, monitoring and verifying how much carbon trees in smallholder farms are removing from the atmosphere has remained a great challenge in developing nations. Devising a reliable way for measuring carbon associated with trees in agricultural landscapes is essential for helping smallholder farmers benefit from emerging carbon markets. This study aimed to develop biomass equations specific to dominant eucalyptus species found in agricultural landscapes in Western Kenya. Allometric relationships were developed by regressing diameter at breast height (DBH) alone or DBH in combination with height, wood density or crown area against the biomass of 48 trees destructively sampled from a 100 km 2 site. DBH alone was a significant predictor variable and estimated aboveground biomass (AGB) with over 95% accuracy. The stems, branches and leaves formed up to 74, 22 and 4% of AGB, respectively, while belowground biomass (BGB) of the harvested trees accounted for 21% of the total tree biomass, yielding an overall root-to-shoot ratio (RS) of 0.27, which varied across tree size. Total tree biomass held in live Eucalyptus trees was estimated to be 24.4 ± 0.01 Mg ha −1 , equivalent to 11.7 ± 0.01 Mg of carbon per hectare. The equations presented provide useful tools for estimating tree carbon stocks of Eucalyptus in agricultural landscapes for bio-energy and carbon accounting. These equations can be applied to Eucalyptus in most agricultural systems with similar agro-ecological settings where tree growth parameters would fall within ranges comparable to the sampled population. -- Highlights: ► Equation with DBH alone estimated aboveground biomass with about 95% accuracy. ► Local generic equations overestimated above- and below-ground biomass by 10 and 48%. ► Height, wood density and crown area data did not improve model accuracy. ► Stems

  4. Interactions between above- and belowground organisms modified in climate change experiments

    Science.gov (United States)

    Stevnbak, Karen; Scherber, Christoph; Gladbach, David J.; Beier, Claus; Mikkelsen, Teis N.; Christensen, Søren

    2012-11-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate can be expected to influence above-belowground interactions. Here, we use a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms. We use an insect herbivore to experimentally increase aboveground herbivory in grass phytometers exposed to all eight combinations of climate change factors for three years. Aboveground herbivory increased the abundance of belowground protozoans, microbial growth and microbial nitrogen availability. Increased CO2 modified these links through a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground-belowground interactions through changes in nutrient availability.

  5. Nitrogen soil emissions and belowground plant processes in Mediterranean annual pastures are altered by ozone exposure and N-inputs

    Science.gov (United States)

    Sánchez-Martín, L.; Bermejo-Bermejo, V.; García-Torres, L.; Alonso, R.; de la Cruz, A.; Calvete-Sogo, H.; Vallejo, A.

    2017-09-01

    Increasing tropospheric ozone (O3) and atmospheric nitrogen (N) deposition alter the structure and composition of pastures. These changes could affect N and C compounds in the soil that in turn can influence soil microbial activity and processes involved in the emission of N oxides, methane (CH4) and carbon dioxide (CO2), but these effects have been scarcely studied. Through an open top chamber (OTC) field experiment, the combined effects of both pollutants on soil gas emissions from an annual experimental Mediterranean community were assessed. Four O3 treatments and three different N input levels were considered. Fluxes of nitric (NO) and nitrous (N2O) oxide, CH4 and CO2 were analysed as well as soil mineral N and dissolved organic carbon. Belowground plant parameters like root biomass and root C and N content were also sampled. Ozone strongly increased soil N2O emissions, doubling the cumulative emission through the growing cycle in the highest O3 treatment, while N-inputs enhanced more slightly NO; CH4 and CO2 where not affected. Both N-gases had a clear seasonality, peaking at the start and at the end of the season when pasture physiological activity is minimal; thus, higher microorganism activity occurred when pasture had a low nutrient demand. The O3-induced peak of N2O under low N availability at the end of the growing season was counterbalanced by the high N inputs. These effects were related to the O3 x N significant interaction found for the root-N content in the grass and the enhanced senescence of the community. Results indicate the importance of the belowground processes, where competition between plants and microorganisms for the available soil N is a key factor, for understanding the ecosystem responses to O3 and N.

  6. Above-ground woody biomass allocation and within tree carbon and nutrient distribution of wild cherry (Prunus avium L. – a case study

    Directory of Open Access Journals (Sweden)

    Christopher Morhart

    2016-02-01

    Full Text Available Background: The global search for new ways to sequester carbon has already reached agricultural lands. Such land constitutes a major potential carbon sink. The production of high value timber within agroforestry systems can facilitate an in-situ carbon storage function. This is followed by a potential long term ex- situ carbon sinkwithin long lasting products such as veneer and furniture. For this purpose wild cherry (Prunus avium L. is an interesting option for middle Europe, yielding high prices on the timber market. Methods: A total number of 39 wild cherry were sampled in 2012 and 2013 to assess the leafless above ground biomass. The complete trees including stem and branches were separated into 1 cm diameter classes. Wood and bark from sub-samples were analysed separately and nutrient content was derived. Models for biomass estimation were constructed for all tree compartments. Results: The smallest diameter classes possess the highest proportion of bark due to smaller cross sectional area. Tree boles with a greater amount of stem wood above 10 cm in diameter will have a more constant bark proportion. Total branch bark proportion also remains relatively constant above d1.3m measurements of 8 cm. A balance is evident between the production of new branches with a low diameter and high bark proportion offset by the thickening and a relative reduction in bark proportion in larger branches. The results show that a single tree with an age of 17 and 18 years can store up to 85 kg of carbon within the aboveground biomass portion, an amount that will increase as the tree matures. Branches display greater nutrient content than stem sections per volume unit which can be attributed to a greater bark proportion. Conclusions: Using the derived models the carbon and the nutrient content of above-ground woody biomass of whole trees can be calculated. Suggested values for carbon with other major and minor nutrients held within relatively immature trees

  7. Changes in carbon and nitrogen allocation, growth and grain yield induced by arbuscular mycorrhizal fungi in wheat (Triticum aestivum L.) subjected to a period of water deficit

    DEFF Research Database (Denmark)

    Zhou, Qin; Ravnskov, Sabine; Jiang, Dong

    2015-01-01

    Drought is a major abiotic factor limiting agricultural crop production. One of the effective ways to increase drought resistance in plants could be to optimize the exploitation of symbiosis with arbuscular mycorrhizal fungi (AMF). Hypothesizing that alleviation of water deficits by AMF in wheat...... will help maintain photosynthetic carbon-use, we studied the role of AMF on gas-exchange, light-use efficiencies, carbon/nitrogen ratios and growth and yield parameters in the contrasting wheat (Triticum aestivum L.) cultivars ‘Vinjett’ and ‘1110’ grown with/without AMF symbiosis. Water deficits applied...... at the floret initiation stage significantly decreased rates of photosynthetic carbon gain, transpiration and stomatal conductance in the two wheat cultivars. AMF increased the rates of photosynthesis, transpiration and stomatal conductance under drought conditions. Water deficits decreased electron transport...

  8. Carbon and Nitrogen dynamics in deciduous and broad leaf trees under drought stress

    Science.gov (United States)

    Joseph, Jobin; Schaub, Marcus; Arend, Matthias; Saurer, Matthias; siegwolf, Rolf; Weiler, Markus; Gessler, Arthur

    2017-04-01

    , we labelled the soil with 15N nitrate by injecting nitrate solution into the soil without strongly changing the water content for investigating nitrogen uptake and distribution along different compartments of the plant soil continuum. We observed a distinct difference in the carbon and nitrogen dynamics and allocation pattern between broad leaf and conifer seedlings. Broad leaf species showed a lower reduction of CO2 assimilation under drought and still allocated significant amounts of the new assimilates to the roots. Especially in maple and oak the belowground transfer of assimilates was kept at high levels even under severe drought stress, while there was a reduction in assimilation transport in beech. Instead, only small amounts of 13C labelled new assimilates arrived in the roots of conifers in the drought treatments. In the deciduous species 15N taken up the roots was more intensively allocated to aboveground tissues compared to conifers under control conditions, which retained the largest amounts within the fine roots. 15N uptake was reduced in the drought treatments in all species assessed. There was, however, no clear relation of this reduction to changes in 13C allocation to the roots. We thus cannot conclude that the reduction of nitrogen uptake is due to reduced transport of new assimilates belowground. We thus need to assume that carbon storage is sufficient to provide energy and carbon for nitrogen uptake and assimilation at least over the short-term. During longer drought periods, however, depletion of carbon stores might adversely affect the nutrient uptake and balance of trees.

  9. The Influence of Allocation on the Carbon Footprint of Electricity Production from Waste Gas, a Case Study for Blast Furnace Gas

    Directory of Open Access Journals (Sweden)

    Joeri Van Mierlo

    2013-03-01

    Full Text Available Producing electricity from waste gas is an after treatment for waste gas while recovering the energy content. This paper addresses the methodology to calculate the effect that waste gas energy recovery has on lowering the impact of climate change. Greenhouse gases are emitted while burning the waste gas. However, a thorough study should include the production of the feedstock as well as the production of the infrastructure. A framework is developed to calculate the environmental impact of electricity production from waste gas with a life cycle approach. The present paper has a twofold purpose: to assess the climate change impact of generating electricity with blast furnace gas (BFG as a waste gas from the steel industry; and to establish a sensitivity assessment of the environmental implications of different allocation rules.

  10. Linking Above- and Belowground Dynamics in Tropical Urban Forests

    Science.gov (United States)

    Atkinson, E. E.; Marin-Spiotta, E.

    2013-12-01

    Secondary forests that emerge after a long history of agriculture can have altered plant community composition and relative abundances of different species. These forests can look and behave differently compared to pre-agricultural forests due changes in primary productivity, resource allocation, and phenology, which can significantly affect processes such as carbon accumulation and nutrient availability. Our research explores how alternative successional trajectories following intensive agricultural use affect linkages among the establishment of novel plant communities, soil nutrient availability and turnover, and soil microbial community composition and function. We hypothesize that different plant species composition due to differing land use legacies and successional trajectories would drive changes in soil microbial community structure and function, affecting soil C and N chemistry and turnover. We conducted this research in the subtropical dry forest life zone of St. Croix, U.S. Virgin Islands where island-wide abandonment of sugarcane resulted in a mosaic of sites in different stages of forest succession. We identified replicate sites with the following post-sugarcane trajectories: 1) natural forest regeneration, 2) low intensity pasture use, followed by reforestation with timber plantation, which are no longer being managed, 3) high intensity pasture use and recent natural forest regeneration, and 4) high intensity pasture use and current active grazing. During 2011-2013, we sampled soils seasonally (0-10 cm) and measured tree species composition. The successional trajectories showed distinct tree species composition. The first two trajectories yielded 40-year old mixed-species secondary forest, dominated by the dry forest tree species Melicoccus bijugatas, Guapira fragrans, Maniklara zapota, and Sideroxylon foetidissimum. The tree species Melicoccus bijugatas primarily drove differences between the first two trajectories (natural forest regeneration vs

  11. Circumpolar assessment of rhizosphere priming shows limited increase in carbon loss estimates for permafrost soils but large regional variability

    Science.gov (United States)

    Wild, B.; Keuper, F.; Kummu, M.; Beer, C.; Blume-Werry, G.; Fontaine, S.; Gavazov, K.; Gentsch, N.; Guggenberger, G.; Hugelius, G.; Jalava, M.; Koven, C.; Krab, E. J.; Kuhry, P.; Monteux, S.; Richter, A.; Shazhad, T.; Dorrepaal, E.

    2017-12-01

    Predictions of soil organic carbon (SOC) losses in the northern circumpolar permafrost area converge around 15% (± 3% standard error) of the initial C pool by 2100 under the RCP 8.5 warming scenario. Yet, none of these estimates consider plant-soil interactions such as the rhizosphere priming effect (RPE). While laboratory experiments have shown that the input of plant-derived compounds can stimulate SOC losses by up to 1200%, the magnitude of RPE in natural ecosystems is unknown and no methods for upscaling exist so far. We here present the first spatial and depth explicit RPE model that allows estimates of RPE on a large scale (PrimeSCale). We combine available spatial data (SOC, C/N, GPP, ALT and ecosystem type) and new ecological insights to assess the importance of the RPE at the circumpolar scale. We use a positive saturating relationship between the RPE and belowground C allocation and two ALT-dependent rooting-depth distribution functions (for tundra and boreal forest) to proportionally assign belowground C allocation and RPE to individual soil depth increments. The model permits to take into account reasonable limiting factors on additional SOC losses by RPE including interactions between spatial and/or depth variation in GPP, plant root density, SOC stocks and ALT. We estimate potential RPE-induced SOC losses at 9.7 Pg C (5 - 95% CI: 1.5 - 23.2 Pg C) by 2100 (RCP 8.5). This corresponds to an increase of the current permafrost SOC-loss estimate from 15% of the initial C pool to about 16%. If we apply an additional molar C/N threshold of 20 to account for microbial C limitation as a requirement for the RPE, SOC losses by RPE are further reduced to 6.5 Pg C (5 - 95% CI: 1.0 - 16.8 Pg C) by 2100 (RCP 8.5). Although our results show that current estimates of permafrost soil C losses are robust without taking into account the RPE, our model also highlights high-RPE risk in Siberian lowland areas and Alaska north of the Brooks Range. The small overall impact of

  12. Effects of simulated root herbivory and fertilizer application on growth and biomass allocation in the clonal perennialSolidago canadensis.

    Science.gov (United States)

    Schmid, B; Miao, S L; Bazzaz, F A

    1990-08-01

    Compensatory growth in response to simulated belowground herbivory was studied in the old-field clonal perennialSolidago canadensis. We grew rootpruned plants and plants with intact root systems in soil with or without fertilizer. For individual current shoots (aerial shoot with rhizome and roots) and for whole clones the following predictions were tested: a) root removal is compensated by increased root growth, b) fertilizer application leads to increased allocation to aboveground plant organs and increased leaf turnover, c) effects of fertilizer application are reduced in rootpruned plants. When most roots (90%) were removed current shoots quickly restored equilibrium between above-and belowground parts by compensatory belowground growth whereas the whole clone responded with reduced aboveground growth. This suggests that parts of a clone which are shared by actively growing shoots act as a buffer that can be used as source of material for compensatory growth in response to herbivory. Current shoots increased aboveground mass and whole clones reduced belowground mass in response to fertilizer application, both leading to increased allocation to aboverground parts. Also with fertilizer application both root-pruned and not root-pruned plants increased leaf and shoot turnover. Unfertilized plants, whether rootpruned or not, showed practically no aboveground growth and very little leaf and shoot turnover. Effects of root removal were as severe or more severe under conditions of high as under conditions of low nutrients, suggesting that negative effects of belowground herbivory are not ameliorated by abundant nutrients. Root removal may negate some effects of fertilizer application on the growth of current shoots and whole clones.

  13. A decade of free‐air CO2 enrichment increased the carbon throughput in a grass‐clover ecosystem but did not drastically change carbon allocation patterns

    DEFF Research Database (Denmark)

    Staddon, Philip Louis; Reinsch, Sabine; Olsson, Pål A.

    2014-01-01

    labelling to determine whether elevated CO2 (+230 μL L−1) concentration changes the fate of recently assimilated carbon in the soil microbial community. Elevated CO2 (eCO2) concentration had an overall positive effect on microbial abundance (P negative bacteria showing significantly...... increased quantities. Gram‐negative bacteria and saprotrophic fungi tended to utilize a higher amount of recently assimilated carbon under eCO2. Arbuscular mycorrhizal fungi (AMF) utilized plant‐assimilated carbon within 1 day after the 13CO2 pulse and 13C uptake patterns in AMF suggest that carbon transfer...

  14. Modulation of carbon and nitrogen allocation in Urtica dioica and Plantago major by elevated CO{sub 2}. Impact of accumulation of nonstructural carbohydrates and ontogenetic drift

    Energy Technology Data Exchange (ETDEWEB)

    Hertog, J. den; Stulen, I.; Fonseca, F.; Delea, P.

    1996-10-01

    Doubling the atmospheric CO{sub 2} concentration from 350 to 700 {mu} l{sup -1} increased the relative growth rate (RGR) of hydroponically grown Urtica dioica L. and Plantagomajor ssp. pleiospherma Pilger only for the first 10-14 days. Previous experiments with P. major indicated that RGR did not respond i proportion to the rate of photosynthesis. The impact of changes in leaf morphology, dry matter partitioning, dry matter chemical composition and ontogenetic drift on this discrepancy is analysed. Soon after the start of the treatment, carbohydrate concentrations were higher at elevated CO{sub 2}; largely due to starch accumulation. An increase in the percentage of leaf dry matter and decreases in the specific leaf area (SLA) and the shoot nitrogen concentration were correlated with an increase in the total nonstructural carbohydrate concentration (TNC). A combination of accumulation of soluble sugars and starch and ontogenetic drift explains the decrease in SLA at the elevated CO{sub 2} level. A similar ontogenetic effect of elevated CO{sub 2} was observed on the specific root length (SRL). Shoot nitrogen concentration and percentage leaf dry matter were not affected. The net diurnal fluctuation of the carbohydrate pool in P. major was equal for both CO{sub 2} concentrations, indicating that the growth response to elevated CO{sub 2} may be ruled by other variables such as sink strength. Elevated CO{sub 2} did not greatly influence the partitioning of nitrogen between soluble and insoluble, reduced N and nitrate, nor the allocation of dry matter between leaf, stem and root. That the root to shoot ratio (F/S) was not affected by elevated CO{sub 2} implies that, to maintain a balanced activity between roots and shoot, no shift in partitioning of dry matter upon doubling of the atmospheric CO{sub 2} concentration is required. (AB)

  15. Growth Response of Aboveground and Belowground of Eustoma grandiflorum to Elevated Co2 in Hydroponic Culture

    Directory of Open Access Journals (Sweden)

    mahin nikoo

    2018-03-01

    Full Text Available Introduction: One of the climate change sign is variation in greenhouse gases in the Earth's atmosphere. Carbon dioxide is the most important greenhouse gas that is released into the atmosphere by humans. It is expected that addition of carbon dioxide could effect the energy balance and global climate. Climate change is effective on agricultural productions. It is clear that different plants have different responses to Co2 variation. These responses are consisting of yield, growth characteristic and variation in root/shoot ratio of plants. On the other hand, using growing media are expanding for plants because of their advantages such as plants nutrient control, reducing the incidence of diseases and pests and increasing the quantity and quality rather than soil cultivation. Properties of various materials as substrates influence directly or indirectly on plant growth and crop production., Hydroponic method can be considered as one of the important methods to optimize water use in agriculture, especially in many countries are located in arid and semi-arid regions that have water crisis. Lisianthus is one of the most beautiful flowers with folded petals in white, blue and purple. I-ts scientific name is Eustoma grandiflorum from the family of Gentianaceae and native to North America. It has variety of annual, biennial or short-lived perennial. The aim of this study was to explore the effect of Co2 enrichment on growth response of aboveground and belowground of Eustoma grandiflorum under increasing of Co2 greenhouse gases in hydroponic culture. Materials and Methods: The experiment was done as a split-plot based on completely randomized experimental design with three replications at greenhouse of Ferdowsi University of Mashhad. The treatments were consists of three concentrations of carbon dioxide (380 as controls, 750 and 1050 ppm as main plots and two cultivars Yodel white and GCREC-blue as subplots. Some characteristic such as plant height

  16. Soil fertility shapes belowground food webs across a regional climate gradient.

    Science.gov (United States)

    Laliberté, Etienne; Kardol, Paul; Didham, Raphael K; Teste, François P; Turner, Benjamin L; Wardle, David A

    2017-10-01

    Changes in soil fertility during pedogenesis affect the quantity and quality of resources entering the belowground subsystem. Climate governs pedogenesis, yet how climate modulates responses of soil food webs to soil ageing remains unexplored because of the paucity of appropriate model systems. We characterised soil food webs along each of four retrogressive soil chronosequences situated across a strong regional climate gradient to show that belowground communities are predominantly shaped by changes in fertility rather than climate. Basal consumers showed hump-shaped responses to soil ageing, which were propagated to higher-order consumers. There was a shift in dominance from bacterial to fungal energy channels with increasing soil age, while the root energy channel was most important in intermediate-aged soils. Our study highlights the overarching importance of soil fertility in regulating soil food webs, and indicates that belowground food webs will respond more strongly to shifts in soil resources than climate change. © 2017 John Wiley & Sons Ltd/CNRS.

  17. Intraseasonal carbon sequestration and allocation in larch trees growing on permafrost in Siberia after 13C labeling (two seasons of 2013-2014 observation).

    Science.gov (United States)

    Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

    2016-12-01

    This research is an attempt to study seasonal translocation patterns of photoassimilated carbon within trees of one of the high latitudes widespread deciduous conifer species Larix gmelinii (Rupr. Rupr). For this purpose, we applied whole-tree labeling by 13 CO 2 , which is a powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree. Experimental plot has been established in a mature 105-year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64°17'13″N, 100°11'55″E, 148 m a.s.l.). Measurements of seasonal photosynthetic activity and foliage parameters (i.e., leaf length, area, biomass, etc.), and sampling were arranged from early growing season (June 8, 2013; May 14, 2014) until yellowing and senescence of needles (September 17, 2013; September 14, 2014). Labeling by 13 C of the tree branch (June 2013, for 3 branch replicates in 3 different trees) and the whole tree was conducted at early (June 2014), middle (July 2014), and late (August 2013) phase of growing season (for different trees in 3 replicates each time) by three pulses [(CO 2 )max = 3000-4000 ppmv, 13 CO 2 (30 % v/v)]. We found at least two different patterns of carbon translocation associated with larch CO 2 assimilation depending on needle phenology. In early period of growing season (June), 13 C appearing in newly developed needles is a result of remobilized storage material use for growth purposes. Then approximately at the end of June, growth processes is switching to storage processes lasting to the end of growing season.

  18. The acclimation of Phaeodactylum tricornutum to blue and red light does not influence the photosynthetic light reaction but strongly disturbs the carbon allocation pattern.

    Directory of Open Access Journals (Sweden)

    Anne Jungandreas

    Full Text Available Diatoms are major contributors to the aquatic primary productivity and show an efficient acclimation ability to changing light intensities. Here, we investigated the acclimation of Phaeodactylum tricornutum to different light quality with respect to growth rate, photosynthesis rate, macromolecular composition and the metabolic profile by shifting the light quality from red light (RL to blue light (BL and vice versa. Our results show that cultures pre-acclimated to BL and RL exhibited similar growth performance, photosynthesis rates and metabolite profiles. However, light shift experiments revealed rapid and severe changes in the metabolite profile within 15 min as the initial reaction of light acclimation. Thus, during the shift from RL to BL, increased concentrations of amino acids and TCA cycle intermediates were observed whereas during the BL to RL shift the levels of amino acids were decreased and intermediates of glycolysis accumulated. Accordingly, on the time scale of hours the RL to BL shift led to a redirection of carbon into the synthesis of proteins, whereas during the BL to RL shift an accumulation of carbohydrates occurred. Thus, a vast metabolic reorganization of the cells was observed as the initial reaction to changes in light quality. The results are discussed with respect to a putative direct regulation of cellular enzymes by light quality and by transcriptional regulation. Interestingly, the short-term changes in the metabolome were accompanied by changes in the degree of reduction of the plastoquinone pool. Surprisingly, the RL to BL shift led to a severe inhibition of growth within the first 48 h which was not observed during the BL to RL shift. Furthermore, during the phase of growth arrest the photosynthetic performance did not change. We propose arguments that the growth arrest could have been caused by the reorganization of intracellular carbon partitioning.

  19. Risk capital allocation

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Smilgins, Aleksandrs

    Risk capital allocation problems have been widely discussed in the academic literature. We consider a company with multiple subunits having individual portfolios. Hence, when portfolios of subunits are merged, a diversification benefit arises: the risk of the company as a whole is smaller than...... the sum of the risks of the individual sub-units. The question is how to allocate the risk capital of the company among the subunits in a fair way. In this paper we propose to use the Lorenz set as an allocation method. We show that the Lorenz set is operational and coherent. Moreover, we propose a set...... of new axioms related directly to the problem of risk capital allocation and show that the Lorenz set satisfies these new axioms in contrast to other well-known coherent methods. Finally, we discuss how to deal with non-uniqueness of the Lorenz set....

  20. CPD Allocations and Awards

    Data.gov (United States)

    Department of Housing and Urban Development — The CPD Allocation and Award database provides filterable on-screen and exportable reports on select programs, such as the Community Development Block Grant Program,...

  1. Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root / shoot herbivores

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2013-11-01

    Full Text Available Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT and elevated atmospheric carbon dioxide (eCO2 are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus and colonisation by the pea aphid (Acyrthosiphon pisum, on three cultivars of a common host plant, lucerne (Medicago sativa. Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 on three trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing, with cultivar ‘Sequel’ achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonisation was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonisation rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

  2. Flowering and biomass allocation in U.S. Atlantic coast Spartina alterniflora.

    Science.gov (United States)

    Crosby, Sarah C; Ivens-Duran, Morgan; Bertness, Mark D; Davey, Earl; Deegan, Linda A; Leslie, Heather M

    2015-05-01

    Salt marshes are highly productive and valuable ecosystems, providing many services on which people depend. Spartina alterniflora Loisel (Poaceae) is a foundation species that builds and maintains salt marshes. Despite this species' importance, much of its basic reproductive biology is not well understood, including flowering phenology, seed production, and the effects of flowering on growth and biomass allocation. We sought to better understand these life history traits and use that knowledge to consider how this species may be affected by climate change. We examined temporal and spatial patterns in flowering and seed production in S. alterniflora at a latitudinal scale (along the U.S. Atlantic coast), regional scale (within New England), and local scale (among subhabitats within marshes) and determined the impact of flowering on growth allocation using field and greenhouse studies. Flowering stem density did not vary along a latitudinal gradient, while at the local scale plants in the less submerged panne subhabitats produced fewer flowers and seeds than those in more frequently submerged subhabitats. We also found that a shift in biomass allocation from above to belowground was temporally related to flowering phenology. We expect that environmental change will affect seed production and that the phenological relationship with flowering will result in limitations to belowground production and thus affect marsh elevation gain. Salt marshes provide an excellent model system for exploring the interactions between plant ecology and ecosystem functioning, enabling better predictions of climate change impacts. © 2015 Botanical Society of America, Inc.

  3. Prerequisite for highly efficient isoprenoid production by cyanobacteria discovered through the over-expression of 1-deoxy-d-xylulose 5-phosphate synthase and carbon allocation analysis.

    Science.gov (United States)

    Kudoh, Kai; Kawano, Yusuke; Hotta, Shingo; Sekine, Midori; Watanabe, Takafumi; Ihara, Masaki

    2014-07-01

    Cyanobacteria have recently been receiving considerable attention owing to their potential as photosynthetic producers of biofuels and biomaterials. Here, we focused on the production of isoprenoids by cyanobacteria, and aimed to provide insight into metabolic engineering design. To this end, we examined the over-expression of a key enzyme in 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, 1-deoxy-d-xylulose 5-phosphate synthase (DXS) in the cyanobacterium Synechocystis sp. PCC6803. In the DXS-over-expression strain (Dxs_ox), the mRNA and protein levels of DXS were 4-times and 1.5-times the levels in the wild-type (WT) strain, respectively. The carotenoid content of the Dxs_ox strain (8.4 mg/g dry cell weight [DCW]) was also up to 1.5-times higher than that in the WT strain (5.6 mg/g DCW), whereas the glycogen content dramatically decreased to an undetectable level. These observations suggested that the carotenoid content in the Dxs_ox strain was increased by consuming glycogen, which is a C-storage compound in cyanobacteria. We also quantified the total sugar (145 and 104 mg/g DCW), total fatty acids (31 and 24 mg/g DCW) and total protein (200 and 240 mg/g DCW) content in the WT and Dxs_ox strains, respectively, which were much higher than the carotenoid content. In particular, approximately 54% of the proteins were phycobiliproteins. This study demonstrated the major destinations of carbon flux in cyanobacteria, and provided important insights into metabolic engineering. Target yield can be improved through optimization of gene expression, the DXS protein stabilization, cell propagation depression and restriction of storage compound synthesis. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Belowground plant biomass of mountain grassland affected by regular and manipulated rainfall in 2006 and 2007

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan

    2008-01-01

    Roč. 1, č. 1 (2008), s. 19-22 ISSN 1803-2451 R&D Projects: GA ČR(CZ) GA526/06/0556 Institutional research plan: CEZ:AV0Z60050516 Keywords : root increments * total belowground biomass * manipulated rainfall Subject RIV: EF - Botanics

  5. Interactions Between a Belowground Herbivore and Primary and Secondary Root Metabolites in Wild Cabbage

    NARCIS (Netherlands)

    Van Geem, Moniek; Harvey, J.A.; Cortesero, A.M.; Raaijmakers, C.E.; Gols, R.

    2015-01-01

    Plants are attacked by both above- and belowground herbivores. Toxic secondary compounds are part of the chemical defense arsenal of plants against a range of antagonists, and are subject to genetic variation. Plants also produce primary metabolites (amino acids, nutrients, sugars) that function as

  6. Plant-Mediated Systemic Interactions Between Pathogens, Parasitic Nematodes, and Herbivores Above- and Belowground

    NARCIS (Netherlands)

    Biere, A.; Goverse, A.

    2016-01-01

    Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within- and cross-compartment plant responses to these groups of phytophages in terms of

  7. Plant-mediated systemic interactions between pathogens, parasitic nematodes, and herbivores above- and belowground

    NARCIS (Netherlands)

    Biere, A.; Goverse, Aska

    2016-01-01

    Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within and cross-compartment plant responses to these groups of phytophages in terms of

  8. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground.

    Directory of Open Access Journals (Sweden)

    Camila Cramer Filgueiras

    Full Text Available Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes.

  9. Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

    Directory of Open Access Journals (Sweden)

    E. Petter Axelsson

    2014-09-01

    Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

  10. Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

    NARCIS (Netherlands)

    Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

    2015-01-01

    There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

  11. Mechanisms and ecological implications of plant-mediated interactions between belowground and aboveground insect herbivores

    NARCIS (Netherlands)

    Papadopoulou, G.V.; Dam, N.M. van

    2017-01-01

    Plant-mediated interactions between belowground (BG) and aboveground (AG) herbivores have received increasing interest recently. However, the molecular mechanisms underlying ecological consequences of BG–AG interactions are not fully clear yet. Herbivore-induced plant defenses are complex and

  12. Interactive effects of above- and belowground herbivory and plant competition on plant growth and defence

    NARCIS (Netherlands)

    Jing, Y.; Raaijmakers, C.; Kostenko, O.; Kos, M.; Mulder, P.P.J.; Bezemer, T.M.

    2015-01-01

    Competition and herbivory are two major factors that can influence plant growth and plant defence. Although these two factors are often studied separately, they do not operate independently. We examined how aboveground herbivory by beet armyworm larvae (Spodoptera exigua) and belowground herbivory

  13. Root interactions in a diverse grassland : the role of root traits in belowground productivity and decomposition

    NARCIS (Netherlands)

    Oram, Natalie J.

    2018-01-01

    Background Plant diversity influences ecosystem functioning. A positive relation between plant diversity and productivity above- and belowground has been established. Aboveground, this effect has been shown to be due to complementarity effects, interactions between species in a mixture

  14. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Junior, Alcides Moino; Pareja, Martin; Borai, Fahiem El; Dickson, Donald W.; Stelinski, Lukasz L.; Duncan, Larry W.

    2016-01-01

    Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes. PMID:27136916

  15. The impacts of climate change and belowground herbivory on aphids via primary metabolites

    Science.gov (United States)

    Ryalls, James M. W.

    Global climate and atmospheric change (summarised as climate change for brevity) may alter patterns of crop damage by insect herbivores, but little is known about how multiple climate change factors, acting in tandem, shape such interactions. Crucially, the specific plant-mediated mechanisms underpinning these effects remain largely unknown. Moreover, research into the effects of climate change on leguminous plant species, which have the ability to fix atmospheric nitrogen (N2) via their association with root nodule-dwelling rhizobial bacteria, and their associated insect herbivores, is surprisingly scarce considering their increasing importance in terrestrial ecosystems worldwide. Using a model legume, lucerne, otherwise known as alfalfa, Medicago sativa (Fabaceae), and a model pest species, the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae), this work addresses how predicted changes in carbon dioxide (CO2) concentrations, temperature and rainfall patterns as well as interactions with other organisms, including the root-feeding weevil Sitona discoideus (Coleoptera: Curculionidae), might shape legume-feeding aphid populations in the future. Recent literature on the impacts of climate change on aphids and the biology and trophic interactions of lucerne aphids specifically were synthesised in chapters one and two, respectively. These chapters highlighted the importance of the interactions between multiple abiotic and biotic variables in shaping aphid population dynamics. Empirical research chapters three to six, using up to five lucerne genotypes (i.e. cultivars) in glasshouse and field experiments, addressed how A. pisum responded to the isolated and combined effects of climate change and root herbivory. In particular, chapter three determined the effects of elevated temperatures (eT) and elevated atmospheric CO2 concentrations (eCO2) on root-feeding S. discoideus larvae and their interaction with A. pisum. Chapter four addressed whether the effects of eT, e

  16. Next Generation Carbon-Nitrogen Dynamics Model

    Science.gov (United States)

    Xu, C.; Fisher, R. A.; Vrugt, J. A.; Wullschleger, S. D.; McDowell, N. G.

    2012-12-01

    Nitrogen is a key regulator of vegetation dynamics, soil carbon release, and terrestrial carbon cycles. Thus, to assess energy impacts on the global carbon cycle and future climates, it is critical that we have a mechanism-based and data-calibrated nitrogen model that simulates nitrogen limitation upon both above and belowground carbon dynamics. In this study, we developed a next generation nitrogen-carbon dynamic model within the NCAR Community Earth System Model (CESM). This next generation nitrogen-carbon dynamic model utilized 1) a mechanistic model of nitrogen limitation on photosynthesis with nitrogen trade-offs among light absorption, electron transport, carboxylation, respiration and storage; 2) an optimal leaf nitrogen model that links soil nitrogen availability and leaf nitrogen content; and 3) an ecosystem demography (ED) model that simulates the growth and light competition of tree cohorts and is currently coupled to CLM. Our three test cases with changes in CO2 concentration, growing temperature and radiation demonstrate the model's ability to predict the impact of altered environmental conditions on nitrogen allocations. Currently, we are testing the model against different datasets including soil fertilization and Free Air CO2 enrichment (FACE) experiments across different forest types. We expect that our calibrated model will considerably improve our understanding and predictability of vegetation-climate interactions.itrogen allocation model evaluations. The figure shows the scatter plots of predicted and measured Vc,max and Jmax scaled to 25 oC (i.e.,Vc,max25 and Jmax25) at elevated CO2 (570 ppm, test case one), reduced radiation in canopy (0.1-0.9 of the radiation at the top of canopy, test case two) and reduced growing temperature (15oC, test case three). The model is first calibrated using control data under ambient CO2 (370 ppm), radiation at the top of the canopy (621 μmol photon/m2/s), the normal growing temperature (30oC). The fitted model

  17. Allocating multiple units

    DEFF Research Database (Denmark)

    Tranæs, Torben; Krishna, Kala

    2002-01-01

    This paper studies the allocation and rent distribution in multi-unit, combinatorial-bid auctions under complete information. We focus on the natural multi-unit analogue of the first-price auction, where buyers bid total payments, pay their bids, and where the seller allocates goods to maximize his...... auction, which is the multi unit analogue of a second-price auction. Furthermore, we characterize these equilibria when valuations take a number of different forms: diminishing marginal valuations, increasing average valuations, and marginal valuations with single turning points...

  18. The roots of defense: plant resistance and tolerance to belowground herbivory.

    Directory of Open Access Journals (Sweden)

    Sean M Watts

    2011-04-01

    Full Text Available There is conclusive evidence that there are fitness costs of plant defense and that herbivores can drive selection for defense. However, most work has focused on above-ground interactions, even though belowground herbivory may have greater impacts on individual plants than above-ground herbivory. Given the role of belowground plant structures in resource acquisition and storage, research on belowground herbivores has much to contribute to theories on the evolution of plant defense. Pocket gophers (Geomyidae provide an excellent opportunity to study root herbivory. These subterranean rodents spend their entire lives belowground and specialize on consuming belowground plant parts.We compared the root defenses of native forbs from mainland populations (with a history of gopher herbivory to island populations (free from gophers for up to 500,000 years. Defense includes both resistance against herbivores and tolerance of herbivore damage. We used three approaches to compare these traits in island and mainland populations of two native California forbs: 1 Eschscholzia californica populations were assayed to compare alkaloid deterrents, 2 captive gophers were used to test the palatability of E. californica roots and 3 simulated root herbivory assessed tolerance to root damage in Deinandra fasciculata and E. californica. Mainland forms of E. californica contained 2.5 times greater concentration of alkaloids and were less palatable to gophers than island forms. Mainland forms of D. fasciculata and, to a lesser extent, E. californica were also more tolerant of root damage than island conspecifics. Interestingly, undamaged island individuals of D. fasciculata produced significantly more fruit than either damaged or undamaged mainland individuals.These results suggest that mainland plants are effective at deterring and tolerating pocket gopher herbivory. Results also suggest that both forms of defense are costly to fitness and thus reduced in the absence of

  19. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    Science.gov (United States)

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved.

  20. Terrestrial biological carbon sequestration: science for enhancement and implementation

    Science.gov (United States)

    Wilfred M. Post; James E. Amonette; Richard Birdsey; Charles T. Jr. Garten; R. Cesar Izaurralde; Philip Jardine; Julie Jastrow; Rattan Lal; Gregg. Marland

    2009-01-01

    The purpose of this chapter is to review terrestrial biological carbon sequestration and evaluate the potential carbon storage capacity if present and new techniques are more aggressively utilized. Photosynthetic CO2 capture from the atmosphere and storage of the C in aboveground and belowground biomass and in soil organic and inorganic forms can...

  1. Cacao Cultivation under Diverse Shade Tree Cover Allows High Carbon Storage and Sequestration without Yield Losses.

    Science.gov (United States)

    Abou Rajab, Yasmin; Leuschner, Christoph; Barus, Henry; Tjoa, Aiyen; Hertel, Dietrich

    2016-01-01

    One of the main drivers of tropical forest loss is their conversion to oil palm, soy or cacao plantations with low biodiversity and greatly reduced carbon storage. Southeast Asian cacao plantations are often established under shade tree cover, but are later converted to non-shaded monocultures to avoid resource competition. We compared three co-occurring cacao cultivation systems (3 replicate stands each) with different shade intensity (non-shaded monoculture, cacao with the legume Gliricidia sepium shade trees, and cacao with several shade tree species) in Sulawesi (Indonesia) with respect to above- and belowground biomass and productivity, and cacao bean yield. Total biomass C stocks (above- and belowground) increased fivefold from the monoculture to the multi-shade tree system (from 11 to 57 Mg ha-1), total net primary production rose twofold (from 9 to 18 Mg C ha-1 yr-1). This increase was associated with a 6fold increase in aboveground biomass, but only a 3.5fold increase in root biomass, indicating a clear shift in C allocation to aboveground tree organs with increasing shade for both cacao and shade trees. Despite a canopy cover increase from 50 to 93%, cacao bean yield remained invariant across the systems (variation: 1.1-1.2 Mg C ha-1 yr-1). The monocultures had a twice as rapid leaf turnover suggesting that shading reduces the exposure of cacao to atmospheric drought, probably resulting in greater leaf longevity. Thus, contrary to general belief, cacao bean yield does not necessarily decrease under shading which seems to reduce physical stress. If planned properly, cacao plantations under a shade tree cover allow combining high yield with benefits for carbon sequestration and storage, production system stability under stress, and higher levels of animal and plant diversity.

  2. Prescribed fire effects on field-derived and simulated forest carbon stocks over time

    Science.gov (United States)

    Nicole M. Vaillant; Alicia L. Reiner; Erin K. Noonan-Wright

    2013-01-01

    To better understand the impact of prescribed fire on carbon stocks, we quantified aboveground and belowground carbon stocks within five pools (live trees and coarse roots, dead trees and coarse roots, live understory vegetation, down woody debris, and litter and duff) and potential carbon emissions from a simulated wildfire before and up to 8 years after prescribed...

  3. When CO2 kills: effects of magmatic CO2 flux on belowground biota at Mammoth Mountain, CA

    Science.gov (United States)

    McFarland, J.; Waldrop, M. P.; Mangan, M.

    2011-12-01

    The biomass, composition, and activity of the soil microbial community is tightly linked to the composition of the aboveground plant community. Microorganisms in aerobic surface soils, both free-living and plant-associated are largely structured by the availability of growth limiting carbon (C) substrates derived from plant inputs. When C availability declines following a catastrophic event such as the death of large swaths of trees, the number and composition of microorganisms in soil would be expected to decline and/or shift to unique microorganisms that have better survival strategies under starvation conditions. High concentrations of volcanic cold CO2 emanating from Mammoth Mountain near Horseshoe Lake on the southwestern edge of Long Valley Caldera, CA has resulted in a large kill zone of tree species, and associated soil microbial species. In July 2010, we assessed belowground microbial community structure in response to disturbance of the plant community along a gradient of soil CO2 concentrations grading from 80% (no plant life). We employed a microbial community fingerprinting technique (automated ribosomal intergenic spacer analysis) to determine changes in overall community composition for three broad functional groups: fungi, bacteria, and archaea. To evaluate changes in ectomycorrhizal fungal associates along the CO2 gradient, we harvested root tips from lodgepole pine seedlings collected in unaffected forest as well as at the leading edge of colonization into the kill zone. We also measured soil C fractions (dissolved organic C, microbial biomass C, and non-extractable C) at 10 and 30 cm depth, as well as NH4+. Not surprisingly, our results indicate a precipitous decline in soil C, and microbial C with increasing soil CO2; phospholipid fatty acid analysis in conjunction with community fingerprinting indicate both a loss of fungal diversity as well as a dramatic decrease in biomass as one proceeds further into the kill zone. This observation was

  4. Applied cost allocation

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Hougaard, Jens Leth; Smilgins, Aleksandrs

    2016-01-01

    This paper deals with empirical computation of Aumann–Shapley cost shares for joint production. We show that if one uses a mathematical programing approach with its non-parametric estimation of the cost function there may be observations in the data set for which we have multiple Aumann–Shapley p...... of assumptions concerning firm behavior. These assumptions enable us to connect inefficient with efficient production and thereby provide consistent ways of allocating the costs arising from inefficiency....

  5. Emissions allocation in transportation routes

    NARCIS (Netherlands)

    Leenders, B.P.J.; Velázquez Martínez, J.; Fransoo, J.C.

    2017-01-01

    This article studies the allocation of CO2 emissions to a specific shipment in routing transportation. The authors show that this problem differs from a cost allocation problem specifically because the concavity condition does not hold necessarily in the CO2 allocation problem. This implies that a

  6. A below-ground herbivore shapes root defensive chemistry in natural plant populations

    OpenAIRE

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Th?o; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root ...

  7. POLICY FRAMEWORK FOR UTILIZATION AND CONSERVATION OF BELOW-GROUND BIODIVERSITY IN KENYA

    Directory of Open Access Journals (Sweden)

    Celline Achieng

    2009-10-01

    Full Text Available The reasons for the lack of inclusion of below-ground biodiversity in the Kenyan policy and legal framework were sought. Gaps were identified in the relevant sectoral policies and laws in regard to the domestication of the Convention on Biological Diversity (CBD. Below -ground biodiversity had no specific schedule in any of the sectoral laws. Most sectoral laws were particular about the larger biodiversity and soils but had no mention of below-ground biodiversity. Material Transfer Agreements and Material Acquisition Agreements that are regarded as tools of domestication of the CBD to guide transfers, exchanges and acquisition of soil organisms lacked a regulating policy. The lack of regulating policy could be attributed to the delay in approval of draft regulations by the Ministry of Environment while the lack of inclusion of below-ground biodiversity in Kenya’s legal and policy framework could be as a result of lack of awareness and appreciation among stakeholders.

  8. Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species.

    Energy Technology Data Exchange (ETDEWEB)

    T.B. Harrington; C.M. Dagley; M.B. Edwards.

    2003-10-01

    Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition and needlefall from overstory pines on understory plant performance. Three 13- to 15-yr-old plantations near Aiken, SC, were thinned to 0, 25, 50, or 100% of nonthinned basal area (19.5 m2 ha-1). Combinations of trenching (to eliminate root competition) and needlefall were applied to areas within each plot, and containerized seedlings of 14 perennial herbaceous species and longleaf pine were planted within each. Overstory crown closure ranged from 0 to 81%, and soil water and available nitrogen varied consistently with pine stocking, trenching, or their combination. Cover of planted species decreased an average of 16.5 and 14.1% as a result of above- and below-ground competition, respectively. Depending on species, needlefall effects were positive, negative, or negligible. Results indicate that understory restoration will be most successful when herbaceous species are established within canopy openings (0.1-0.2 ha) managed to minimize negative effects from above- and belowground competition and needlefall.

  9. Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

    Science.gov (United States)

    Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

    2014-01-01

    Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

  10. Seasonal carbon storage and growth in Mediterranean tree seedlings under different water conditions.

    Science.gov (United States)

    Sanz-Pérez, Virginia; Castro-Díez, Pilar; Joffre, Richard

    2009-09-01

    In all Mediterranean-type ecosystems, evergreen and deciduous trees differing in wood anatomy, growth pattern and leaf habit coexist, suggesting distinct adaptative responses to environmental constraints. This study examined the effects of summer water stress on carbon (C) storage and growth in seedlings of three coexisting Mediterranean trees that differed in phenology and wood anatomy characteristics: Quercus ilex subsp. ballota (Desf.) Samp., Quercus faginea Lam. and Pinus halepensis L. Seedlings were subjected to two levels of watering during two consecutive summers and achieved a minimum of -0.5 and -2.5 MPa of predawn water potential in the control and water stress treatment, respectively. Both Quercus species concentrated their growth in the early growing season, demanding higher C in early spring but replenishing C-stores in autumn. These species allocated more biomass to roots, having larger belowground starch and lipid reserves. Quercus species differed in seasonal storage dynamics from P. halepensis. This species allocated most of its C to aboveground growth, which occurred gradually during the growing season, leading to fewer C-reserves. Soluble sugar and starch concentrations sharply declined in August in P. halepensis, probably because reserves support respiration demands as this species closed stomata earlier under water stress. Drought reduced growth of the three species, mainly in Q. faginea and P. halepensis, but not C-reserves, suggesting that growth under water stress conditions is not limited by C-availability.

  11. Effects of Manipulated Above- and Belowground Organic Matter Input on Soil Respiration in a Chinese Pine Plantation

    Science.gov (United States)

    Zhao, Bo; Wu, Lianhai; Zhang, Chunyu; Zhao, Xiuhai; Gadow, Klaus v.

    2015-01-01

    Alteration in the amount of soil organic matter input can have profound effect on carbon dynamics in forest soils. The objective of our research was to determine the response in soil respiration to above- and belowground organic matter manipulation in a Chinese pine (Pinus tabulaeformis) plantation. Five organic matter treatments were applied during a 2-year experiment: both litter removal and root trenching (LRRT), only litter removal (LR), control (CK), only root trenching (RT) and litter addition (LA). We found that either aboveground litter removal or root trenching decreased soil respiration. On average, soil respiration rate was significantly decreased in the LRRT treatment, by about 38.93% ± 2.01% compared to the control. Soil respiration rate in the LR treatment was 30.65% ± 1.87% and in the RT treatment 17.65% ± 1.95% lower than in the control. Litter addition significantly increased soil respiration rate by about 25.82% ± 2.44% compared to the control. Soil temperature and soil moisture were the main factors affecting seasonal variation in soil respiration. Up to the 59.7% to 82.9% seasonal variation in soil respiration is explained by integrating soil temperature and soil moisture within each of the various organic matter treatments. The temperature sensitivity parameter, Q 10, was higher in the RT (2.72) and LA (3.19) treatments relative to the control (2.51), but lower in the LRRT (1.52) and LR treatments (1.36). Our data suggest that manipulation of soil organic matter input can not only alter soil CO2 efflux, but also have profound effect on the temperature sensitivity of organic carbon decomposition in a temperate pine forest. PMID:25970791

  12. Cost allocation with limited information

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tind, Jørgen

    This article investigates progressive development of Aumann-Shapley cost allocation in a multilevel organizational or production structure. In particular, we study a linear parametric programming setup utilizing the Dantzig-Wolfe decomposition procedure. Typically cost allocation takes place after...... all activities have been performed, for example by finishing all outputs. Here the allocation is made progressively with suggestions for activities. I other words cost allocation is performed in parallel for example with a production planning process. This development does not require detailed...... information about some technical constraints in order to make the cost allocation....

  13. Optimal allocation of leaf epidermal area for gas exchange

    OpenAIRE

    de Boer, Hugo J.; Price, Charles A.; Wagner-Cremer, Friederike; Dekker, Stefan C.; Franks, Peter J.; Veneklaas, Erik J.

    2016-01-01

    Summary A long?standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of ...

  14. Seasonal patterns of carbon allocation to respiratory pools in 60-yr-old deciduous (Fagus sylvatica) and evergreen (Picea abies) trees assessed via whole-tree stable carbon isotope labeling.

    Science.gov (United States)

    Kuptz, Daniel; Fleischmann, Frank; Matyssek, Rainer; Grams, Thorsten E E

    2011-07-01

    • The CO(2) efflux of adult trees is supplied by recent photosynthates and carbon (C) stores. The extent to which these C pools contribute to growth and maintenance respiration (R(G) and R(M), respectively) remains obscure. • Recent photosynthates of adult beech (Fagus sylvatica) and spruce (Picea abies) trees were labeled by exposing whole-tree canopies to (13) C-depleted CO(2). Label was applied three times during the year (in spring, early summer and late summer) and changes in the stable C isotope composition (δ(13) C) of trunk and coarse-root CO(2) efflux were quantified. • Seasonal patterns in C translocation rate (CTR) and fractional contribution of label to CO(2) efflux (F(Label-Max)) were found. CTR was fastest during early summer. In beech, F(Label-Max) was lowest in spring and peaked in trunks during late summer (0.6 ± 0.1, mean ± SE), whereas no trend was observed in coarse roots. No seasonal dynamics in F(Label-Max) were found in spruce. • During spring, the R(G) of beech trunks was largely supplied by C stores. Recent photosynthates supplied growth in early summer and refilled C stores in late summer. In spruce, CO(2) efflux was constantly supplied by a mixture of stored (c. 75%) and recent (c. 25%) C. The hypothesis that R(G) is exclusively supplied by recent photosynthates was rejected for both species. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  15. Carbon input belowground is the major C flux contributing to leaf litter mass loss

    DEFF Research Database (Denmark)

    Rubino, Mauro; Dungait; Evershed

    2010-01-01

    and analysed for their total C and 13C content. Gas chromatography (GC), GC–mass spectrometry (MS) and GC-combustion-isotope ratio (GC/C/IRMS) were used to analyse phospholipid fatty acids (PLFA) extracted from soil samples to identify the groups of soil micro-organisms that had incorporated litter-derived C...... and to determine the quantity of C incorporated by the soil microbial biomass (SMB). By the end of the experiment, the litter had lost about 80% of its original weight. The fraction of litter C lost as an input into the soil (67 ± 12% of the total C loss) was found to be twice as much as the fraction released...

  16. Ecosystem carbon partitioning: aboveground net primary productivity correlates with the root carbon input in different land use types of Southern Alps

    Science.gov (United States)

    Rodeghiero, Mirco; Martinez, Cristina; Gianelle, Damiano; Camin, Federica; Zanotelli, Damiano; Magnani, Federico

    2013-04-01

    Terrestrial plant carbon partitioning to above- and below-ground compartments can be better understood by integrating studies on biomass allocation and estimates of root carbon input based on the use of stable isotopes. These experiments are essential to model ecosystem's metabolism and predict the effects of global change on carbon cycling. Using in-growth soil cores in conjunction with the 13C natural abundance method we quantified net plant-derived root carbon input into the soil, which has been pointed out as the main unaccounted NPP (net primary productivity) component. Four land use types located in the Trentino Region (northern Italy) and representing a range of aboveground net primary productivity (ANPP) values (155-868 gC m-2 y-1) were investigated: conifer forest, apple orchard, vineyard and grassland. Cores, filled with soil of a known C4 isotopic signature were inserted at 18 sampling points for each site and left in place for twelve months. After extraction, cores were analysed for %C and d13C, which were used to calculate the proportion of new plant-derived root C input by applying a mass balance equation. The GPP (gross primary productivity) of each ecosystem was determined by the eddy covariance technique whereas ANPP was quantified with a repeated inventory approach. We found a strong and significant relationship (R2 = 0.93; p=0.03) between ANPP and the fraction of GPP transferred to the soil as root C input across the investigated sites. This percentage varied between 10 and 25% of GPP with the grassland having the lowest value and the apple orchard the highest. Mechanistic ecosystem carbon balance models could benefit from this general relationship since ANPP is routinely and easily measured at many sites. This result also suggests that by quantifying site-specific ANPP, root carbon input can be reliably estimated, as opposed to using arbitrary root/shoot ratios which may under- or over-estimate C partitioning.

  17. Theory of stable allocations

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2014-01-01

    Full Text Available The Swedish Royal Academy awarded the 2012 Nobel Prize in Economics to Lloyd Shapley and Alvin Roth, for the theory of stable allocations and the practice of market design. These two American researchers worked independently from each other, combining basic theory and empirical investigations. Through their experiments and practical design they generated a flourishing field of research and improved the performance of many markets. Born in 1923 in Cambridge, Massachusetts, Shapley defended his doctoral thesis at Princeton University in 1953. For many years he worked at RAND, and for more than thirty years he was a professor at UCLA University. He published numerous scientific papers, either by himself or in cooperation with other economists.

  18. SSC accelerator availability allocation

    International Nuclear Information System (INIS)

    Dixon, K.T.; Franciscovich, J.

    1991-03-01

    Superconducting Super Collider (SSC) operational availability is an area of major concern, judged by the Central Design Group to present such risk that use of modern engineering tools would be essential to program success. Experience has shown that as accelerator beam availability falls below about 80%, efficiency of physics experiments degrades rapidly due to inability to maintain adequate coincident accelerator and detector operation. For this reason, the SSC availability goal has been set at 80%, even though the Fermi National Accelerator Laboratory accelerator, with a fraction of the SSC's complexity, has only recently approached that level. This paper describes the allocation of the top-level goal to part-level reliability and maintainability requirements, and it gives the results of parameter sensitivity studies designed to help identify the best approach to achieve the needed system availability within funding and schedule constraints. 1 ref., 12 figs., 4 tabs

  19. Importance measures and resource allocation

    International Nuclear Information System (INIS)

    Guey, C.N.; Morgan, T.; Hughes, E.A.

    1987-01-01

    This paper discusses various importance measures and their practical relevance to allocating resources. The characteristics of importance measures are illustrated through simple examples. Important factors associated with effectively allocating resources to improve plant system performance or to prevent system degradation are discussed. It is concluded that importance measures are only indicative of and not equal to the risk significance of a component, system, or event. A decision framework is suggested to provide a comprehensive basis for resource allocation

  20. IPO Allocations: Discriminatory or Discretionary?

    OpenAIRE

    William Wilhelm; Alexander Ljungqvist

    2001-01-01

    We estimate the structural links between IPO allocations, pre-market information production, and initial underpricing returns, within the context of theories of bookbuilding. Using a sample of both US and international IPOs we find evidence of the following: ? IPO allocation policies favour institutional investors, both in the US and worldwide. ? Increasing institutional allocations results in offer prices that deviate more from the indicative price range established prior to bankers’ efforts...

  1. Zinc allocation and re-allocation in rice

    NARCIS (Netherlands)

    Stomph, T.J.; Jiang, W.; Putten, van der P.E.L.; Struik, P.C.

    2014-01-01

    Aims: Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation

  2. Research on allocation efficiency of the daisy chain allocation algorithm

    Science.gov (United States)

    Shi, Jingping; Zhang, Weiguo

    2013-03-01

    With the improvement of the aircraft performance in reliability, maneuverability and survivability, the number of the control effectors increases a lot. How to distribute the three-axis moments into the control surfaces reasonably becomes an important problem. Daisy chain method is simple and easy to be carried out in the design of the allocation system. But it can not solve the allocation problem for entire attainable moment subset. For the lateral-directional allocation problem, the allocation efficiency of the daisy chain can be directly measured by the area of its subset of attainable moments. Because of the non-linear allocation characteristic, the subset of attainable moments of daisy-chain method is a complex non-convex polygon, and it is difficult to solve directly. By analyzing the two-dimensional allocation problems with a "micro-element" idea, a numerical calculation algorithm is proposed to compute the area of the non-convex polygon. In order to improve the allocation efficiency of the algorithm, a genetic algorithm with the allocation efficiency chosen as the fitness function is proposed to find the best pseudo-inverse matrix.

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

    Science.gov (United States)

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

    2017-01-01

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

  4. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  5. Linking above and belowground responses to global change at community and ecosystem scales.

    Energy Technology Data Exchange (ETDEWEB)

    Antoninka, Anita [Northern Arizona University; Wolf, Julie [Northern Arizona University; Bowker, Matt [Northern Arizona University; Classen, Aimee T [ORNL; JohnsonPhD, Dr Nancy C [Northern Arizona University

    2009-01-01

    Cryptic belowground organisms are difficult to observe and their responses to global changes are not well understood. Nevertheless, there is reason to believe that interactions among above- and belowground communities may mediate ecosystem responses to global change. We used grassland mesocosms to manipulate the abundance of one important group of soil organisms, arbuscular mycorrhizal (AM) fungi, and to study community and ecosystem responses to CO2 and N enrichment. After two growing seasons, biomass responses of plant communities were recorded, and soil community responses were measured using microscopy, phospholipid fatty acids (PLFA) and community-level physiological profiles (CLPP). Ecosystem responses were examined by measuring net primary production (NPP), evapotranspiration, total soil organic matter (SOM), and extractable mineral N. Structural equation modeling was used to examine the causal relationships among treatments and response variables. We found that while CO2 and N tended to directly impact ecosystem functions (evapotranspiration and NPP, respectively), AM fungi indirectly impacted ecosystem functions by strongly influencing the composition of plant and soil communities. For example, the presence of AM fungi had a strong influence on other root and soil fungi and soil bacteria. We found that the mycotrophic status of the dominant plant species in the mesocosms determined whether the presence of AM fungi increased or decreased NPP. Mycotrophic grasses dominated the mesocosm communities during the first growing season, and thus, the mycorrhizal treatments had the highest NPP. In contrast, non-mycotrophic forbs were dominant during the second growing season and thus, the mycorrhizal treatments had the lowest NPP. The composition of the plant community strongly influenced soil N; and the composition of the soil organisms strongly influenced SOM accumulation in the mesocosms. These results show how linkages between above- and belowground communities

  6. Carbon pools along headwater streams with differing valley geometry in Rocky Mountain National Park, Colorado (Abstract)

    Science.gov (United States)

    Kathleen A. Dwire; Ellen E. Wohl; Nicholas A. Sutfin; Roberto A. Bazan; Lina Polvi-Pilgrim

    2012-01-01

    Headwaters are known to be important in the global carbon cycle, yet few studies have investigated carbon (C) pools along stream-riparian corridors. To better understand the spatial distribution of C storage in headwater fluvial networks, we estimated above- and below-ground C pools in 100-m-long reaches in six different valley types in Rocky Mountain National Park,...

  7. Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms.

    Directory of Open Access Journals (Sweden)

    Kristina A Stinson

    2006-05-01

    Full Text Available The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat.

  8. Efficient Metropolitan Resource Allocation

    Directory of Open Access Journals (Sweden)

    Richard Arnott

    2016-05-01

    Full Text Available Over the past 30 years Calgary has doubled in size, from a population of 640,645 in 1985 to 1,230,915 in 2015. During that time the City has had five different mayors, hosted the Winter Olympics, and expanded the C-Train from 25 platforms to 45. Calgary’s Metropolitan Area has grown too, with Airdrie, Chestermere, Okotoks and Cochrane growing into full-fledged cities, ripe with inter-urban commuters.* And with changes to provincial legislation in the mid-’90s, rural Rocky View County and the Municipal District of Foothills are now real competitors for residential, commercial and industrial development that in the past would have been considered urban. In this metropolitan system, where people live, their household structure, and their place of work informs the services they need to conduct their daily lives, and directly impacts the spatial character of the City and the broader region. In sum, Metropolitan Calgary is increasingly complex. Calgary and the broader metropolitan area will continue to grow, even with the current economic slowdown. Frictions within Calgary, between the various municipalities in the metropolitan area, and the priorities of other local authorities (such as the School Boards and Alberta Health Services will continue to impact the agendas of local politicians and their ability to answer to the needs of their residents. How resources – whether it is hard infrastructure, affordable housing, classrooms, or hospital beds – are allocated over space and how these resources are funded, directly impacts these relationships. This technical paper provides my perspective as an urban economist on the efficient allocation of resources within a metropolitan system in general, with reference to Calgary where appropriate, and serves as a companion to the previously released “Reflections on Calgary’s Spatial Structure: An Urban Economists Critique of Municipal Planning in Calgary.” It is hoped that the concepts reviewed

  9. Soil organic carbon stability across a Mediterranean oak agroecosystem

    Science.gov (United States)

    Leslie M. Roche; James F. Chang; Johan Six; Anthony T. O' Geen; Kenneth W. Tate

    2015-01-01

    Rangelands are estimated to cover 30 to 50 percent of the world's land surface and have significant belowground carbon (C) storage potential. Given their geographical extent, many have suggested that even modest changes in C storage via management practices could alter the global C cycle, creating climate change mitigation opportunities. Our objective was to...

  10. Carbon flux from plants to soil microbes is highly sensitive to nitrogen addition and biochar amendment

    Science.gov (United States)

    Kaiser, C.; Solaiman, Z. M.; Kilburn, M. R.; Clode, P. L.; Fuchslueger, L.; Koranda, M.; Murphy, D. V.

    2012-04-01

    The release of carbon through plant roots to the soil has been recognized as a governing factor for soil microbial community composition and decomposition processes, constituting an important control for ecosystem biogeochemical cycles. Moreover, there is increasing awareness that the flux of recently assimilated carbon from plants to the soil may regulate ecosystem response to environmental change, as the rate of the plant-soil carbon transfer will likely be affected by increased plant C assimilation caused by increasing atmospheric CO2 levels. What has received less attention so far is how sensitive the plant-soil C transfer would be to possible regulations coming from belowground, such as soil N addition or microbial community changes resulting from anthropogenic inputs such as biochar amendments. In this study we investigated the size, rate and sensitivity of the transfer of recently assimilated plant C through the root-soil-mycorrhiza-microbial continuum. Wheat plants associated with arbuscular mycorrhizal fungi were grown in split-boxes which were filled either with soil or a soil-biochar mixture. Each split-box consisted of two compartments separated by a membrane which was penetrable for mycorrhizal hyphae but not for roots. Wheat plants were only grown in one compartment while the other compartment served as an extended soil volume which was only accessible by mycorrhizal hyphae associated with the plant roots. After plants were grown for four weeks we used a double-labeling approach with 13C and 15N in order to investigate interactions between C and N flows in the plant-soil-microorganism system. Plants were subjected to an enriched 13CO2 atmosphere for 8 hours during which 15NH4 was added to a subset of split-boxes to either the root-containing or the root-free compartment. Both, 13C and 15N fluxes through the plant-soil continuum were monitored over 24 hours by stable isotope methods (13C phospho-lipid fatty acids by GC-IRMS, 15N/13C in bulk plant

  11. Endogeneously arising network allocation rules

    NARCIS (Netherlands)

    Slikker, M.

    2006-01-01

    In this paper we study endogenously arising network allocation rules. We focus on three allocation rules: the Myerson value, the position value and the component-wise egalitarian solution. For any of these three rules we provide a characterization based on component efficiency and some balanced

  12. Risk allocation under liquidity constraints

    NARCIS (Netherlands)

    Csóka, P.; Herings, P.J.J.

    2013-01-01

    Risk allocation games are cooperative games that are used to attribute the risk of a financial entity to its divisions. In this paper, we extend the literature on risk allocation games by incorporating liquidity considerations. A liquidity policy specifies state-dependent liquidity requirements that

  13. Do plants modulate biomass allocation in response to petroleum pollution?

    Science.gov (United States)

    Nie, Ming; Yang, Qiang; Jiang, Li-Fen; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

    2010-01-01

    Biomass allocation is an important plant trait that responds plastically to environmental heterogeneities. However, the effects on this trait of pollutants owing to human activities remain largely unknown. In this study, we investigated the response of biomass allocation of Phragmites australis to petroleum pollution by a 13CO2 pulse-labelling technique. Our data show that plant biomass significantly decreased under petroleum pollution, but the root–shoot ratio for both plant biomass and 13C increased with increasing petroleum concentration, suggesting that plants could increase biomass allocation to roots in petroleum-polluted soil. Furthermore, assimilated 13C was found to be significantly higher in soil, microbial biomass and soil respiration after soils were polluted by petroleum. These results suggested that the carbon released from roots is rapidly turned over by soil microbes under petroleum pollution. This study found that plants can modulate biomass allocation in response to petroleum pollution. PMID:20484231

  14. Belowground Interactions Impact the Soil Bacterial Community, Soil Fertility, and Crop Yield in Maize/Peanut Intercropping Systems

    Directory of Open Access Journals (Sweden)

    Qisong Li

    2018-02-01

    Full Text Available Intercropping has been widely used to control disease and improve yield in agriculture. In this study, maize and peanut were used for non-separation intercropping (NS, semi-separation intercropping (SS using a nylon net, and complete separation intercropping (CS using a plastic sheet. In field experiments, two-year land equivalent ratios (LERs showed yield advantages due to belowground interactions when using NS and SS patterns as compared to monoculture. In contrast, intercropping without belowground interactions (CS showed a yield disadvantage. Meanwhile, in pot experiments, belowground interactions (found in NS and SS improved levels of soil-available nutrients (nitrogen (N and phosphorus (P and enzymes (urease and acid phosphomonoesterase as compared to intercropping without belowground interactions (CS. Soil bacterial community assay showed that soil bacterial communities in the NS and SS crops clustered together and were considerably different from the CS crops. The diversity of bacterial communities was significantly improved in soils with NS and SS. The abundance of beneficial bacteria, which have the functions of P-solubilization, pathogen suppression, and N-cycling, was improved in maize and peanut soils due to belowground interactions through intercropping. Among these bacteria, numbers of Bacillus, Brevibacillus brevis, and Paenibacillus were mainly increased in the maize rhizosphere. Burkholderia, Pseudomonas, and Rhizobium were mainly increased in the peanut rhizosphere. In conclusion, using maize and peanut intercropping, belowground interactions increased the numbers of beneficial bacteria in the soil and improved the diversity of the bacterial community, which was conducive to improving soil nutrient (N and P supply capacity and soil microecosystem stability.

  15. Arbuscular Mycorrhizal Fungi and Plant Chemical Defence: Effects of Colonisation on Aboveground and Belowground Metabolomes.

    Science.gov (United States)

    Hill, Elizabeth M; Robinson, Lynne A; Abdul-Sada, Ali; Vanbergen, Adam J; Hodge, Angela; Hartley, Sue E

    2018-02-01

    Arbuscular mycorrhizal fungal (AMF) colonisation of plant roots is one of the most ancient and widespread interactions in ecology, yet the systemic consequences for plant secondary chemistry remain unclear. We performed the first metabolomic investigation into the impact of AMF colonisation by Rhizophagus irregularis on the chemical defences, spanning above- and below-ground tissues, in its host-plant ragwort (Senecio jacobaea). We used a non-targeted metabolomics approach to profile, and where possible identify, compounds induced by AMF colonisation in both roots and shoots. Metabolomics analyses revealed that 33 compounds were significantly increased in the root tissue of AMF colonised plants, including seven blumenols, plant-derived compounds known to be associated with AMF colonisation. One of these was a novel structure conjugated with a malonyl-sugar and uronic acid moiety, hitherto an unreported combination. Such structural modifications of blumenols could be significant for their previously reported functional roles associated with the establishment and maintenance of AM colonisation. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms.

  16. Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

    Science.gov (United States)

    Ghimire, Bardan; Riley, William J.; Koven, Charles D.; Mu, Mingquan; Randerson, James T.

    2016-06-01

    In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis rates are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.

  17. Zinc allocation and re-allocation in rice

    Science.gov (United States)

    Stomph, Tjeerd Jan; Jiang, Wen; Van Der Putten, Peter E. L.; Struik, Paul C.

    2014-01-01

    Aims: Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation and re-allocation in rice. Methods: Two solution culture experiments using 70Zn applications at different times during crop development and an experiment on within-grain distribution of Zn are reported. In addition, results from two earlier published experiments are re-analyzed and re-interpreted. Results: A budget analysis showed that plant zinc accumulation during grain filling was larger than zinc allocation to the grains. Isotope data showed that zinc taken up during grain filling was only partly transported directly to the grains and partly allocated to the leaves. Zinc taken up during grain filling and allocated to the leaves replaced zinc re-allocated from leaves to grains. Within the grains, no major transport barrier was observed between vascular tissue and endosperm. At low tissue Zn concentrations, rice plants maintained concentrations of about 20 mg Zn kg−1 dry matter in leaf blades and reproductive tissues, but let Zn concentrations in stems, sheath, and roots drop below this level. When plant zinc concentrations increased, Zn levels in leaf blades and reproductive tissues only showed a moderate increase while Zn levels in stems, roots, and sheaths increased much more and in that order. Conclusions: In rice, the major barrier to enhanced zinc allocation towards grains is between stem and reproductive tissues. Enhancing root to shoot transfer will not contribute proportionally to grain zinc enhancement. PMID:24478788

  18. Nutrient allocations and metabolism in two Collembola with contrasting reproduction and growth strategies

    DEFF Research Database (Denmark)

    Larsen, Thomas; Ventura, Marc; Damgaard, Christian

    2009-01-01

    1.  Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal's adaptation to a particular habitat. This study investigated how two detrivores with contrasting life-history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and meta...

  19. Free allocation in the European Emissions Trading System (EU ETS): identifying efficient mechanisms through to 2030

    International Nuclear Information System (INIS)

    Jalard, Matthieu; Alberola, Emilie

    2015-11-01

    In a world with asymmetrical climate policies, the conclusions of the European Council of October 2014 agreed on continuing the allocation of free CO 2 emissions allowances beyond 2020 to industrial sectors in the EU ETS. This statement has been confirmed in the European Commission's proposal to revise EU ETS directive for phase IV disclosed in July 2015. The stated objective is to ensure that the most efficient industrial installations do not face undue carbon costs which would lead to carbon leakages. Furthermore, free allocations should not undermine the incentive to cut CO 2 emissions, lead to distortions or windfall profits and reduce the auctioning share of allowances. From 2013 to 2020, the allocation of free allowances has been defined according to harmonized European rules based on benchmarks (carbon intensity targets) and historical output adjusted to the free allocation cap by applying the Cross-Sectoral Correction Factor (CSCF). What would be the impact of pursuing the current mechanism through to 2030? Does the EU Commissions' proposal of 15 July respond to the Council's requirements? Which alternative mechanisms could do so? This study examines four scenarios and their potential consequences. - Scenario 1 continues the current free allocation mechanism until 2030. The volume of free allocations thus calculated would be higher than the available free allocation cap and would need to be reduced by a Cross-Sectoral Correction Factor (CSCF) of 66% in 2030. Carbon costs would thus increase for all installations, regardless their exposure to carbon leakages, reducing the protection of most exposed sectors, while widely allocating sectors with limited exposure. - Scenario 2 analyses the proposal to implement an allocation mechanism based on recent industrial output combined with appropriate updating of benchmarks. This allocation method is more effective in combating carbon leakage, as it gives clearer incentive to maintain domestic production

  20. International Development Aid Allocation Determinants

    OpenAIRE

    Tapas Mishra; Bazoumana Ouattara; Mamata Parhi

    2012-01-01

    This paper investigates the factors explaining aid allocation by bilateral and multilateral donors. We use data for 146 aid recipient countries over the period 1990-2007 and employ Bayesian Averaging of Classical Estimates Approach (BACE) approach and find that both the recipient need and donor interest motives are `significant' determinants of bilateral and multilateral aid allocation process. Our results also indicate that the measures for recipient need and donor interests vary from bilate...

  1. Application of an allocation methodology

    International Nuclear Information System (INIS)

    Youngblood, R.

    1989-01-01

    This paper presents a method for allocating resources to elements of a system for the purpose of achieving prescribed levels of defense-in-depth at minimal cost. The method makes extensive use of logic modelling. An analysis of a simplified high-level waste repository is used as an illustrative application of the method. It is shown that it is possible to allocate quality control costs (or demonstrate performance) in an optimal way over elements of a conceptual design

  2. Coastal landforms and accumulation of mangrove peat increase carbon sequestration and storage.

    Science.gov (United States)

    Ezcurra, Paula; Ezcurra, Exequiel; Garcillán, Pedro P; Costa, Matthew T; Aburto-Oropeza, Octavio

    2016-04-19

    Given their relatively small area, mangroves and their organic sediments are of disproportionate importance to global carbon sequestration and carbon storage. Peat deposition and preservation allows some mangroves to accrete vertically and keep pace with sea-level rise by growing on their own root remains. In this study we show that mangroves in desert inlets in the coasts of the Baja California have been accumulating root peat for nearly 2,000 y and harbor a belowground carbon content of 900-34,00 Mg C/ha, with an average value of 1,130 (± 128) Mg C/ha, and a belowground carbon accumulation similar to that found under some of the tallest tropical mangroves in the Mexican Pacific coast. The depth-age curve for the mangrove sediments of Baja California indicates that sea level in the peninsula has been rising at a mean rate of 0.70 mm/y (± 0.07) during the last 17 centuries, a value similar to the rates of sea-level rise estimated for the Caribbean during a comparable period. By accreting on their own accumulated peat, these desert mangroves store large amounts of carbon in their sediments. We estimate that mangroves and halophyte scrubs in Mexico's arid northwest, with less than 1% of the terrestrial area, store in their belowground sediments around 28% of the total belowground carbon pool of the whole region.

  3. Measuring and modeling carbon stock change estimates for US forests and uncertainties from apparent inter-annual variability

    Science.gov (United States)

    James E. Smith; Linda S. Heath

    2015-01-01

    Our approach is based on a collection of models that convert or augment the USDA Forest Inventory and Analysis program survey data to estimate all forest carbon component stocks, including live and standing dead tree aboveground and belowground biomass, forest floor (litter), down deadwood, and soil organic carbon, for each inventory plot. The data, which include...

  4. Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia

    NARCIS (Netherlands)

    Chen, J.Y.; Bongers, F.; Cao, K.F.; Cai, Z.Q.

    2008-01-01

    Abstract: In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test

  5. Influence of presence and spatial arrangement of belowground insects on host-plant selection of aboveground insects: a field study

    NARCIS (Netherlands)

    Soler, J.J.; Schaper, S.V.; Bezemer, T.M.; Cortesero, A.M.; Hoffmeister, T.S.; Van der Putten, W.H.; Vet, L.E.M.; Harvey, J.A.

    2009-01-01

    1. Several studies have shown that above- and belowground insects can interact by influencing each others growth, development, and survival when they feed on the same host-plant. In natural systems, however, insects can make choices on which plants to oviposit and feed. A field experiment was

  6. Short- and longterm impacts of Acacia longifolia invasion on belowground processes of a Mediterranean coastal dune ecosystem

    DEFF Research Database (Denmark)

    Marchante, Elizabete; Kjøller, Annelise; Struwe, Sten

    2008-01-01

    to new areas, displacing the native vegetation. These invaded ecosystems contrast with the native dune ecosystems that are typically dominated by herb and shrub communities. This study characterizes belowground changes to the native environment as a result of recent (20 y...

  7. Interactions between above- and belowground biota: importance for small-scale vegetation mosaics in a grassland ecosystem

    NARCIS (Netherlands)

    Blomqvist, M.M.; Olff, H.; Blaauw, M.B.; Bongers, T.; Van der Putten, W.H.

    2000-01-01

    Grasslands are often characterised by small-scale mosaics in plant community composition that contribute to their diversity. Although above- and belowground biota can both cause such mosaics, few studies have addressed their interacting effects. We studied multi-trophic interactions between

  8. Interactions between above- and belowground biota : importance for small-scale vegetation mosaics in a grassland ecosystem

    NARCIS (Netherlands)

    Blomqvist, N.M.; Olff, H.; Blaauw, M.B.; Bongers, T.; Putten, van der W.H.

    2000-01-01

    Grasslands are often characterised by small-scale mosaics in plant community composition that contribute to their diversity. Although above- and belowground biota can both cause such mosaics, few studies have addressed their interacting effects. We studied multi-trophic interactions between

  9. Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)

    Science.gov (United States)

    CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

  10. Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L

    Science.gov (United States)

    Anna M. Jensen; Magnus Lof; Emile S. Gardiner

    2011-01-01

    For a tree seedling to successfully establish in dense shrubbery, it must maintain function under heterogeneous resource availability. We evaluated leaf-level acclimation in photosynthetic capacity, seedling-level transpiration, and seedling morphology and growth to gain an understanding of the effects of above- and below-ground competition on Quercus robur seedlings....

  11. Systemic above- and belowground cross talk: hormone-based responses triggered by Heterodera schachtii and shoot herbivores in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Kammerhofer, N.; Egger, B.; Dobrev, Petre; Vaňková, Radomíra; Hofmann, J.; Schausberger, P.; Wieczorek, K.

    2015-01-01

    Roč. 66, č. 22 (2015), s. 7005-7017 ISSN 0022-0957 R&D Projects: GA MŠk LD14120 Institutional support: RVO:61389030 Keywords : Aboveground–belowground interactions * Frankliniella occidentalis * herbivores Subject RIV: EF - Botanics Impact factor: 5.677, year: 2015

  12. Short-term belowground responses to thinning and burning treatments in southwestern ponderosa pine forests of the USA

    Science.gov (United States)

    Steven T. Overby; Stephen C. Hart

    2016-01-01

    Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important...

  13. Decomposition by ectomycorrhizal fungi alters soil carbon storage in a simulation model

    DEFF Research Database (Denmark)

    Moore, J. A. M.; Jiang, J.; Post, W. M.

    2015-01-01

    Carbon cycle models often lack explicit belowground organism activity, yet belowground organisms regulate carbon storage and release in soil. Ectomycorrhizal fungi are important players in the carbon cycle because they are a conduit into soil for carbon assimilated by the plant. It is hypothesized...... to decompose soil organic matter. Our review highlights evidence demonstrating the potential for ectomycorrhizal fungi to decompose soil organic matter. Our model output suggests that ectomycorrhizal activity accounts for a portion of carbon decomposed in soil, but this portion varied with plant productivity...... and the mycorrhizal carbon uptake strategy simulated. Lower organic matter inputs to soil were largely responsible for reduced soil carbon storage. Using mathematical theory, we demonstrated that biotic interactions affect predictions of ecosystem functions. Specifically, we developed a simple function to model...

  14. How should INGOs allocate resources?

    Directory of Open Access Journals (Sweden)

    Scott Wisor

    2012-02-01

    Full Text Available International Non-governmental Organizations (INGOs face difficult choices when choosing to allocate resources. Given that the resources made available to INGOs fall far short of what is needed to reduce massive human rights deficits, any chosen scheme of resource allocation requires failing to reach other individuals in great need. Facing these moral opportunity costs, what moral reasons should guide INGO resource allocation? Two reasons that clearly matter, and are recognized by philosophers and development practitioners, are the consequences (or benefit or harm reduction of any given resource allocation and the need (or priority of individual beneficiaries. If accepted, these reasons should lead INGOs to allocate resources to a limited number of countries where the most prioritarian weighted harm reduction will be achieved. I make three critiques against this view. First, on grounds the consequentialist accepts, I argue that INGOs ought to maintain a reasonably wide distribution of resources. Second, I argue that even if one is a consequentialist, consequentialism ought not act as an action guiding principle for INGOs. Third, I argue that additional moral reasons should influence decision making about INGO resource allocation. Namely, INGO decision making should attend to relational reasons, desert, respect for agency, concern for equity, and the importance of expressing a view of moral wrongs.

  15. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  16. Allocation of Nutrients to Somatic Tissues in Young Ovariectomized Grasshoppers

    Science.gov (United States)

    Judd, Evan T.; Hatle, John D.; Drewry, Michelle D.; Wessels, Frank J.; Hahn, Daniel A.

    2010-01-01

    The disposable soma hypothesis predicts that when reproduction is reduced, life span is increased because more nutrients are invested in the soma, increasing somatic repair. Rigorously testing the hypothesis requires tracking nutrients from ingestion to allocation to the soma or to reproduction. Fruit flies on life-extending dietary restriction increase allocation to the soma “relative” to reproduction, suggesting that allocation of nutrients can be associated with extension of life span. Here, we use stable isotopes to track ingested nutrients in ovariectomized grasshoppers during the first oviposition cycle. Previous work has shown that ovariectomy extends life span, but investment of protein in reproduction is not reduced until after the first clutch of eggs is laid. Because ovariectomy does not affect investment in reproduction at this age, the disposable soma hypothesis would predict that ovariectomy should also not affect investment in somatic tissues. We developed grasshopper diets with distinct signatures of 13C and 15N, but that produced equivalent reproductive outputs. These diets are, therefore, appropriate for the reciprocal switches in diet needed for tracking ingested nutrients. Incorporation of stable isotopes into eggs showed that grasshoppers are income breeders, especially for carbon. Allocation to the fat body of nitrogen ingested as adults was slightly increased by ovariectomy; this was our only result that was not consistent with the disposable soma hypothesis. In contrast, ovariectomy did not affect allocation of nitrogen to femoral muscles. Further, allocation of carbon to the fat body or femoral muscles did not appear to be affected by ovariectomy. Total anti-oxidant activities in the hemolymph and femoral muscles were not affected by ovariectomy. These experiments showed that allocation of nutrients was altered little by ovariectomy in young grasshoppers. Additional studies on older individuals are needed to further test the disposable

  17. The importance of aboveground–belowground interactions on the evolution and maintenance of variation in plant defense traits

    Science.gov (United States)

    van Geem, Moniek; Gols, Rieta; van Dam, Nicole M.; van der Putten, Wim H.; Fortuna, Taiadjana; Harvey, Jeffrey A.

    2013-01-01

    Over the past two decades a growing body of empirical research has shown that many ecological processes are mediated by a complex array of indirect interactions occurring between rhizosphere-inhabiting organisms and those found on aboveground plant parts. Aboveground–belowground studies have thus far focused on elucidating processes and underlying mechanisms that mediate the behavior and performance of invertebrates in opposite ecosystem compartments. Less is known about genetic variation in plant traits such as defense as that may be driven by above- and belowground trophic interactions. For instance, although our understanding of genetic variation in aboveground plant traits and its effects on community-level interactions is well developed, little is known about the importance of aboveground–belowground interactions in driving this variation. Plant traits may have evolved in response to selection pressures from above- and below-ground interactions from antagonists and mutualists. Here, we discuss gaps in our understanding of genetic variation in plant-related traits as they relate to aboveground and belowground multitrophic interactions. When metabolic resources are limiting, multiple attacks by antagonists in both domains may lead to trade-offs. In nature, these trade-offs may critically depend upon their effects on plant fitness. Natural enemies of herbivores may also influence selection for different traits via top–down control. At larger scales these interactions may generate evolutionary “hotspots” where the expression of various plant traits is the result of strong reciprocal selection via direct and indirect interactions. The role of abiotic factors in driving genetic variation in plant traits is also discussed. PMID:24348484

  18. A below-ground herbivore shapes root defensive chemistry in natural plant populations.

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-03-30

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

  19. Belowground ectomycorrhizal fungal communities respond to liming in three southern Swedish coniferous forest stands

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Clemmensen, Karina

    2009-01-01

    In this study we report on changes in the belowground ectomycorrhizal fungal communities in southern Swedish coniferous forests as a consequence of liming with 3-7 ton limestone per hectare 16 years prior to the study. A total of 107 ectomycorrhizal fungi were identified from 969 independently...... sampled root tips by sequencing the internal transcribed spacer region of the ribosomal DNA. Forty, 59 and 51 species were identified in three pine and spruce forests. Within all sites only about 25% of the species overlapped between the limed and the reference areas. However, the most abundant species...... were often found in both limed and reference plots and 60-70% of the root tips at each site were colonised by species occurring in both limed and reference plots. Across all three sites, fungal species belonging to the genus Tylospora and the order Pezizales became significantly more frequent in limed...

  20. Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

    Science.gov (United States)

    Ueyama, M.; Ichii, K.; Hirata, R.; Takagi, K.; Asanuma, J.; Machimura, T.; Nakai, Y.; Ohta, T.; Saigusa, N.; Takahashi, Y.; Hirano, T.

    2010-03-01

    Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales. The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE), gross primary productivity (GPP), ecosystem respiration (RE), and evapotranspiration (ET). Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values. The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation. Although this study substantially

  1. Disruption of a belowground mutualism alters interactions between plants and their floral visitors.

    Science.gov (United States)

    Cahill, James F; Elle, Elizabeth; Smith, Glen R; Shore, Bryon H

    2008-07-01

    Plants engage in diverse and intimate interactions with unrelated taxa. For example, aboveground floral visitors provide pollination services, while belowground arbuscular mycorrhizal fungi (AMF) enhance nutrient capture. Traditionally in ecology, these processes were studied in isolation, reinforcing the prevailing assumption that these above- and belowground processes were also functionally distinct. More recently, there has been a growing realization that the soil surface is not a barrier to many ecological interactions, particularly those involving plants (who live simultaneously above and below ground). Because of the potentially large impact that mycorrhizae and floral visitors can have on plant performance and community dynamics, we designed an experiment to test whether these multi-species mutualisms were interdependent under field conditions. Using benomyl, a widely used fungicide, we suppressed AMF in a native grassland, measuring plant, fungal, and floral-visitor responses after three years of fungal suppression. AMF suppression caused a shift in the community of floral visitors from large-bodied bees to small-bodied bees and flies, and reduced the total number of floral visits per flowering stem 67% across the 23 flowering species found in the plots. Fungal suppression has species-specific effects on floral visits for the six most common flowering plants in this experiment. Exploratory analyses suggest these results were due to changes in floral-visitor behavior due to altered patch-level floral display, rather than through direct effects of AMF suppression on floral morphology. Our findings indicate that AMF are an important, and overlooked, driver of floral-visitor community structure with the potential to affect pollination services. These results support the growing body of research indicating that interactions among ecological interactions can be of meaningful effect size under natural field conditions and may influence individual performance

  2. Early root overproduction not triggered by nutrients decisive for competitive success belowground.

    Directory of Open Access Journals (Sweden)

    Francisco M Padilla

    Full Text Available Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information regarding root interactions is limited, as molecular methods quantifying species abundance belowground have only recently become available.In monoculture, the grass Festuca rubra had higher root densities and a faster rate of soil nitrate depletion than Plantago lanceolata, projecting the first as a better competitor for nutrients. However, Festuca lost in competition with Plantago. Plantago not only replaced the lower root mass of its competitor, but strongly overproduced roots: with only half of the plants in mixture than in monoculture, Plantago root densities in mixture were similar or higher than those in its monocultures. These responses occurred equally in a nutrient-rich and nutrient-poor soil layer, and commenced immediately at the start of the experiment when root densities were still low and soil nutrient concentrations high.Our results suggest that species may achieve competitive superiority for nutrients by root growth stimulation prior to nutrient depletion, induced by the presence of a competitor species, rather than by a better ability to compete for nutrients per se. The root overproduction by which interspecific neighbors are suppressed independent of nutrient acquisition is consistent with predictions from game theory. Our results emphasize that root competition may be driven by other mechanisms than is currently assumed. The long-term consequences of these mechanisms for community dynamics are discussed.

  3. Declining plant nitrogen supply and carbon accumulation in ageing primary boreal forest ecosystems

    Science.gov (United States)

    Högberg, Mona N.; Yarwood, Stephanie A.; Trumbore, Susan; Högberg, Peter

    2016-04-01

    Boreal forest soils are commonly characterized by a low plant nitrogen (N) supply. A high tree below-ground allocation of carbon (C) to roots and soil microorganisms in response to the shortage of N may lead to high microbial immobilisation of N, thus aggravating the N limitation. We studied the N supply at a Swedish boreal forest ecosystem chronosequence created by new land rising out of the sea due to iso-static rebound. The youngest soils develop with meadows by the coast, followed by a zone of dinitrogen fixing alder trees, and primary boreal conifer forest on ground up to 560 years old. With increasing ecosystem age, the proportion of microbial C out of the total soil C pool from the youngest to the oldest coniferous ecosystem was constant (c. 1-1.5%), whereas immobilised N (microbial N out of total soil N) increased and approached the levels commonly observed in similar boreal coniferous forests (c. 6-7 %), whereas gross N mineralization declined. Simultaneously, plant foliar N % decreased and the natural abundance of N-15 in the soil increased. More specifically, the difference in N-15 between plant foliage and soil increased, which is related to greater retention of N-15 relative to N-14 by ectomycorrhizal fungi as N is taken up from the soil and some N is transferred to the plant host. In the conifer forest, where these changes were greatest, we found increased fungal biomass in the F- and H-horizons of the mor-layer, in which ectomycorrhizal fungi are known to dominate (the uppermost horizon with litter and moss is dominated by saprotrophic fungi). Hence, we propose that the decreasing N supply to the plants and the subsequent decline in plant production in ageing boreal forests is linked to high tree belowground C allocation to C limited ectomycorrhizal fungi (and other soil microorganisms), a strong sink for available soil N. Data on organic matter C-14 suggested that the largest input of recently fixed plant C occurred in the younger coniferous forest

  4. Cost allocation in distribution planning

    Energy Technology Data Exchange (ETDEWEB)

    Engevall, S

    1997-12-31

    This thesis concerns cost allocation problems in distribution planning. The cost allocation problems we study are illustrated using the distribution planning situation at the Logistics department of Norsk Hydro Olje AB. The planning situation is modeled as a Traveling Salesman Problem and a Vehicle Routing Problem with an inhomogeneous fleet. The cost allocation problems are the problems of how to divide the transportation costs among the customers served in each problem. The cost allocation problems are formulated as cooperative games, in characteristic function form, where the customers are defined to be the players. The games contain five and 21 players respectively. Game theoretical solution concepts such as the core, the nucleolus, the Shapley value and the {tau}-value are discussed. From the empirical results we can, among other things, conclude that the core of the Traveling Salesman Game is large, and that the core of the Vehicle Routing Game is empty. In the accounting of Norsk Hydro the cost per m{sup 3} can be found for each tour. We conclude that for a certain definition of the characteristic function, a cost allocation according to this principle will not be included in the core of the Traveling Salesman Game. The models and methods presented in this thesis can be applied to transportation problems similar to that of Norsk Hydro, independent of the type of products that are delivered. 96 refs, 11 figs, 26 tabs

  5. Cost allocation in distribution planning

    Energy Technology Data Exchange (ETDEWEB)

    Engevall, S.

    1996-12-31

    This thesis concerns cost allocation problems in distribution planning. The cost allocation problems we study are illustrated using the distribution planning situation at the Logistics department of Norsk Hydro Olje AB. The planning situation is modeled as a Traveling Salesman Problem and a Vehicle Routing Problem with an inhomogeneous fleet. The cost allocation problems are the problems of how to divide the transportation costs among the customers served in each problem. The cost allocation problems are formulated as cooperative games, in characteristic function form, where the customers are defined to be the players. The games contain five and 21 players respectively. Game theoretical solution concepts such as the core, the nucleolus, the Shapley value and the {tau}-value are discussed. From the empirical results we can, among other things, conclude that the core of the Traveling Salesman Game is large, and that the core of the Vehicle Routing Game is empty. In the accounting of Norsk Hydro the cost per m{sup 3} can be found for each tour. We conclude that for a certain definition of the characteristic function, a cost allocation according to this principle will not be included in the core of the Traveling Salesman Game. The models and methods presented in this thesis can be applied to transportation problems similar to that of Norsk Hydro, independent of the type of products that are delivered. 96 refs, 11 figs, 26 tabs

  6. Cost allocation in distribution planning

    International Nuclear Information System (INIS)

    Engevall, S.

    1996-01-01

    This thesis concerns cost allocation problems in distribution planning. The cost allocation problems we study are illustrated using the distribution planning situation at the Logistics department of Norsk Hydro Olje AB. The planning situation is modeled as a Traveling Salesman Problem and a Vehicle Routing Problem with an inhomogeneous fleet. The cost allocation problems are the problems of how to divide the transportation costs among the customers served in each problem. The cost allocation problems are formulated as cooperative games, in characteristic function form, where the customers are defined to be the players. The games contain five and 21 players respectively. Game theoretical solution concepts such as the core, the nucleolus, the Shapley value and the τ-value are discussed. From the empirical results we can, among other things, conclude that the core of the Traveling Salesman Game is large, and that the core of the Vehicle Routing Game is empty. In the accounting of Norsk Hydro the cost per m 3 can be found for each tour. We conclude that for a certain definition of the characteristic function, a cost allocation according to this principle will not be included in the core of the Traveling Salesman Game. The models and methods presented in this thesis can be applied to transportation problems similar to that of Norsk Hydro, independent of the type of products that are delivered. 96 refs, 11 figs, 26 tabs

  7. The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: implications for post-thaw carbon loss

    Science.gov (United States)

    Jonathan A. O' Donnell; Jennifer W. Harden; A. David McGuire; Mikhail Z. Kanevskiy; M. Torre Jorgenson; Xiaomei Xu

    2010-01-01

    High-latitude regions store large amounts of organic carbon (OC) in active-layer soils and permafrost, accounting for nearly half of the global belowground OC pool. In the boreal region, recent warming has promoted changes in the fire regime, which may exacerbate rates of permafrost thaw and alter soil OC dynamics in both organic and mineral soil. We examined how...

  8. Application of an allocation methodology

    International Nuclear Information System (INIS)

    Youngblood, R.; de Oliveira, L.F.S.

    1989-01-01

    This paper presents a method for allocating resources to elements of a system for the purpose of achieving prescribed levels of defense-in-depth at minimal cost. The method makes extensive use of logic modelling. An analysis of a simplified high-level waste repository is used as an illustrative application of the method. It is shown that it is possible to allocate quality control costs (or demonstrated performance) in an optimal way over elements of a conceptual design. 6 refs., 3 figs., 2 tabs

  9. Allocation Problems and Market Design

    DEFF Research Database (Denmark)

    Smilgins, Aleksandrs

    The thesis contains six independent papers with a common theme: Allocation problems and market design. The first paper is concerned with fair allocation of risk capital where independent autonomous subunits have risky activities and together constitute the entity's total risk, whose associated risk...... at a certain point in time involves countries that have excess demand and countries that have surplus of green energy. The problem addressed here is how the gains from trade ought to influence the way that members of the grid share common costs. The fifth paper extends the classical two-sided one...

  10. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Directory of Open Access Journals (Sweden)

    Scott Ferrenberg

    2016-10-01

    Full Text Available Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species and belowground (species active in organic and mineral soil layers arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community and modified Winkler funnels (belowground community and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the

  11. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Science.gov (United States)

    Martinez, Alexander S.; Faist, Akasha M.

    2016-01-01

    Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity) among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod

  12. Comparison of modeling approaches for carbon partitioning: Impact on estimates of global net primary production and equilibrium biomass of woody vegetation from MODIS GPP

    Science.gov (United States)

    Takeshi Ise; Creighton M. Litton; Christian P. Giardina; Akihiko Ito

    2010-01-01

    Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long�]lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta-analysis of forest ecosystems suggests that carbon partitioning...

  13. Regulating nutrient allocation in plants

    Science.gov (United States)

    Udvardi, Michael; Yang, Jiading; Worley, Eric

    2014-12-09

    The invention provides coding and promoter sequences for a VS-1 and AP-2 gene, which affects the developmental process of senescence in plants. Vectors, transgenic plants, seeds, and host cells comprising heterologous VS-1 and AP-2 genes are also provided. Additionally provided are methods of altering nutrient allocation and composition in a plant using the VS-1 and AP-2 genes.

  14. Centralized Allocation in Multiple Markets

    DEFF Research Database (Denmark)

    Monte, Daniel; Tumennasan, Norovsambuu

    The problem of allocating indivisible objects to different agents, where each indi vidual is assigned at most one object, has been widely studied. Pápai (2000) shows that the set of strategy-proof, nonbossy, Pareto optimal and reallocation-proof rules are hierarchical exchange rules | generalizat...... and nonbossy rules are sequential dictatorships, a special case of Pápai's hierarchical exchange rules....

  15. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, van K.; Maanen, van P.P.

    2005-01-01

    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make

  16. Planning and Resource Allocation Management.

    Science.gov (United States)

    Coleman, Jack W.

    1986-01-01

    Modern scientific management techniques provide college administrators with valuable planning and resource allocation insights and enhances the decision process. The planning model should incorporate assessment, strategic planning, dynamic and long-term budgeting, operational planning, and feedback and control for actual operations. (MSE)

  17. Relating belowground microbial composition to the taxonomic, phylogenetic, and functional trait distributions of trees in a tropical forest.

    Science.gov (United States)

    Barberán, Albert; McGuire, Krista L; Wolf, Jeffrey A; Jones, F Andrew; Wright, Stuart Joseph; Turner, Benjamin L; Essene, Adam; Hubbell, Stephen P; Faircloth, Brant C; Fierer, Noah

    2015-12-01

    The complexities of the relationships between plant and soil microbial communities remain unresolved. We determined the associations between plant aboveground and belowground (root) distributions and the communities of soil fungi and bacteria found across a diverse tropical forest plot. Soil microbial community composition was correlated with the taxonomic and phylogenetic structure of the aboveground plant assemblages even after controlling for differences in soil characteristics, but these relationships were stronger for fungi than for bacteria. In contrast to expectations, the species composition of roots in our soil core samples was a poor predictor of microbial community composition perhaps due to the patchy, ephemeral, and highly overlapping nature of fine root distributions. Our ability to predict soil microbial composition was not improved by incorporating information on plant functional traits suggesting that the most commonly measured plant traits are not particularly useful for predicting the plot-level variability in belowground microbial communities. © 2015 John Wiley & Sons Ltd/CNRS.

  18. CARBON SEQUESTRATION AND PLANT COMMUNITY DYNAMICS FOLLOWING REFORESTATION OF TROPICAL PASTURE.

    Science.gov (United States)

    WHENDEE L. SILVER; LARA M. KUEPPERS; ARIEL E. LUGO; REBECCA OSTERTAG; VIRGINIA MATZEK

    2004-01-01

    Conversion of abandoned cattle pastures to secondary forests and plantations in the tropics has been proposed as a means to increase rates of carbon (C) sequestration from the atmosphere and enhance local biodiversity. We used a long-term tropical reforestation project (55–61 yr) to estimate rates of above- and belowground C sequestration and to investigate the impact...

  19. Empirical evidence that soil carbon formation from plant inputs is positively related to microbial growth

    Science.gov (United States)

    Mark A. Bradford; Ashley D. Keiser; Christian A. Davies; Calley A. Mersmann; Michael S. Strickland

    2012-01-01

    Plant-carbon inputs to soils in the form of dissolved sugars, organic acids and amino acids fuel much of heterotrophic microbial activity belowground. Initial residence times of these compounds in the soil solution are on the order of hours, with microbial uptake a primary removal mechanism. Through microbial biosynthesis, the dissolved compounds become dominant...

  20. Isometric scaling of above- and below-ground biomass at the individual and community levels in the understorey of a sub-tropical forest.

    Science.gov (United States)

    Cheng, Dongliang; Zhong, Quanlin; Niklas, Karl J; Ma, Yuzhu; Yang, Yusheng; Zhang, Jianhua

    2015-02-01

    Empirical studies and allometric partitioning (AP) theory indicate that plant above-ground biomass (MA) scales, on average, one-to-one (isometrically) with below-ground biomass (MR) at the level of individual trees and at the level of entire forest communities. However, the ability of the AP theory to predict the biomass allocation patterns of understorey plants has not been established because most previous empirical tests have focused on canopy tree species or very large shrubs. In order to test the AP theory further, 1586 understorey sub-tropical forest plants from 30 sites in south-east China were harvested and examined. The numerical values of the scaling exponents and normalization constants (i.e. slopes and y-intercepts, respectively) of log-log linear MA vs. MR relationships were determined for all individual plants, for each site, across the entire data set, and for data sorted into a total of 19 sub-sets of forest types and successional stages. Similar comparisons of MA/MR were also made. The data revealed that the mean MA/MR of understorey plants was 2·44 and 1·57 across all 1586 plants and for all communities, respectively, and MA scaled nearly isometrically with respect to MR, with scaling exponents of 1·01 for all individual plants and 0·99 for all communities. The scaling exponents did not differ significantly among different forest types or successional stages, but the normalization constants did, and were positively correlated with MA/MR and negatively correlated with scaling exponents across all 1586 plants. The results support the AP theory's prediction that MA scales nearly one-to-one with MR (i.e. MA ∝ MR (≈1·0)) and that plant biomass partitioning for individual plants and at the community level share a strikingly similar pattern, at least for the understorey plants examined in this study. Furthermore, variation in environmental conditions appears to affect the numerical values of normalization constants, but not the scaling exponents

  1. Contribution of above- and below-ground plant traits to the structure and function of grassland soil microbial communities.

    Science.gov (United States)

    Legay, N; Baxendale, C; Grigulis, K; Krainer, U; Kastl, E; Schloter, M; Bardgett, R D; Arnoldi, C; Bahn, M; Dumont, M; Poly, F; Pommier, T; Clément, J C; Lavorel, S

    2014-10-01

    Abiotic properties of soil are known to be major drivers of the microbial community within it. Our understanding of how soil microbial properties are related to the functional structure and diversity of plant communities, however, is limited and largely restricted to above-ground plant traits, with the role of below-ground traits being poorly understood. This study investigated the relative contributions of soil abiotic properties and plant traits, both above-ground and below-ground, to variations in microbial processes involved in grassland nitrogen turnover. In mountain grasslands distributed across three European sites, a correlative approach was used to examine the role of a large range of plant functional traits and soil abiotic factors on microbial variables, including gene abundance of nitrifiers and denitrifiers and their potential activities. Direct effects of soil abiotic parameters were found to have the most significant influence on the microbial groups investigated. Indirect pathways via plant functional traits contributed substantially to explaining the relative abundance of fungi and bacteria and gene abundances of the investigated microbial communities, while they explained little of the variance in microbial activities. Gene abundances of nitrifiers and denitrifiers were most strongly related to below-ground plant traits, suggesting that they were the most relevant traits for explaining variation in community structure and abundances of soil microbes involved in nitrification and denitrification. The results suggest that consideration of plant traits, and especially below-ground traits, increases our ability to describe variation in the abundances and the functional characteristics of microbial communities in grassland soils. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. The effect of long-term changes in plant inputs on soil carbon stocks

    Science.gov (United States)

    Georgiou, K.; Li, Z.; Torn, M. S.

    2017-12-01

    Soil organic carbon (SOC) is the largest actively-cycling terrestrial reservoir of C and an integral component of thriving natural and managed ecosystems. C input interventions (e.g., litter removal or organic amendments) are common in managed landscapes and present an important decision for maintaining healthy soils in sustainable agriculture and forestry. Furthermore, climate and land-cover change can also affect the amount of plant C inputs that enter the soil through changes in plant productivity, allocation, and rooting depth. Yet, the processes that dictate the response of SOC to such changes in C inputs are poorly understood and inadequately represented in predictive models. Long-term litter manipulations are an invaluable resource for exploring key controls of SOC storage and validating model representations. Here we explore the response of SOC to long-term changes in plant C inputs across a range of biomes and soil types. We synthesize and analyze data from long-term litter manipulation field experiments, and focus our meta-analysis on changes to total SOC stocks, microbial biomass carbon, and mineral-associated (`protected') carbon pools and explore the relative contribution of above- versus below-ground C inputs. Our cross-site data comparison reveals that divergent SOC responses are observed between forest sites, particularly for treatments that increase C inputs to the soil. We explore trends among key variables (e.g., microbial biomass to SOC ratios) that inform soil C model representations. The assembled dataset is an important benchmark for evaluating process-based hypotheses and validating divergent model formulations.

  3. Carbon Sequestration by Perennial Energy Crops: Is the Jury Still Out?

    Science.gov (United States)

    Agostini, Francesco; Gregory, Andrew S; Richter, Goetz M

    Soil organic carbon (SOC) changes associated with land conversion to energy crops are central to the debate on bioenergy and their potential carbon neutrality. Here, the experimental evidence on SOC under perennial energy crops (PECs) is synthesised to parameterise a whole systems model and to identify uncertainties and knowledge gaps determining PECs being a sink or source of greenhouse gas (GHG). For Miscanthus and willow ( Salix spp.) and their analogues (switchgrass, poplar), we examine carbon (C) allocation to above- and belowground residue inputs, turnover rates and retention in the soil. A meta-analysis showed that studies on dry matter partitioning and C inputs to soils are plentiful, whilst data on turnover are rare and rely on few isotopic C tracer studies. Comprehensive studies on SOC dynamics and GHG emissions under PECs are limited and subsoil processes and C losses through leaching remain unknown. Data showed dynamic changes of gross C inputs and SOC stocks depending on stand age. C inputs and turnover can now be specifically parameterised in whole PEC system models, whilst dependencies on soil texture, moisture and temperature remain empirical. In conclusion, the annual net SOC storage change exceeds the minimum mitigation requirement (0.25 Mg C ha -1 year -1 ) under herbaceous and woody perennials by far (1.14 to 1.88 and 0.63 to 0.72 Mg C ha -1 year -1 , respectively). However, long-term time series of field data are needed to verify sustainable SOC enrichment, as the physical and chemical stabilities of SOC pools remain uncertain, although they are essential in defining the sustainability of C sequestration (half-life >25 years).

  4. Root carbon inputs to the rhizosphere stimulate extracellular enzyme activity and increase nitrogen availability in temperate forest soils

    Science.gov (United States)

    Brzostek, E. R.; Phillips, R.; Dragoni, D.; Drake, J. E.; Finzi, A. C.

    2011-12-01

    The mobilization of nitrogen (N) from soil organic matter in temperate forest soils is controlled by the microbial production and activity of extracellular enzymes. The exudation of carbon (C) by tree roots into the rhizosphere may subsidize the microbial production of extracellular enzymes in the rhizosphere and increase the access of roots to N. The objective of this research was to investigate whether rates of root exudation and the resulting stimulation of extracellular enzyme activity in the rhizosphere (i.e., rhizosphere effect) differs between tree species that form associations with ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi. This research was conducted at two temperate forest sites, the Harvard Forest (HF) in Central MA and the Morgan Monroe State Forest (MMSF) in Southern IN. At the HF, we measured rates of root exudation and the rhizosphere effects on enzyme activity, N cycling, and C mineralization in AM and ECM soils. At the MMSF, we recently girdled AM and ECM dominated plots to examine the impact of severing belowground C allocation on rhizosphere processes. At both sites, the rhizosphere effect on proteolytic, chitinolytic and ligninolytic enzyme activities was greater in ECM soils than in AM soils. In particular, higher rates of proteolytic enzyme activity increased the availability of amino acid-N in ECM rhizospheres relative to the bulk soils. Further, this stimulation of enzyme activity was directly correlated with higher rates of C mineralization in the rhizosphere than in the bulk soil. Although not significantly different between species, root exudation of C comprised 3-10% of annual gross primary production at the HF. At the MMSF, experimental girdling led to a larger decline in soil respiration and enzyme activity in ECM plots than in AM plots. In both ECM and AM soils, however, girdling resulted in equivalent rates of enzyme activity in rhizosphere and corresponding bulk soils. The results of this study contribute to the

  5. Grassland to woodland transitions: Dynamic response of microbial community structure and carbon use patterns

    Science.gov (United States)

    Creamer, Courtney A.; Filley, Timothy R.; Boutton, Thomas W.; Rowe, Helen I.

    2016-06-01

    Woodland encroachment into grasslands is a globally pervasive phenomenon attributed to land use change, fire suppression, and climate change. This vegetation shift impacts ecosystem services such as ground water allocation, carbon (C) and nutrient status of soils, aboveground and belowground biodiversity, and soil structure. We hypothesized that woodland encroachment would alter microbial community structure and function and would be related to patterns in soil C accumulation. To address this hypothesis, we measured the composition and δ13C values of soil microbial phospholipids (PLFAs) along successional chronosequences from C4-dominated grasslands to C3-dominated woodlands (small discrete clusters and larger groves) spanning up to 134 years. Woodland development increased microbial biomass, soil C and nitrogen (N) concentrations, and altered microbial community composition. The relative abundance of gram-negative bacteria (cy19:0) increased linearly with stand age, consistent with decreases in soil pH and/or greater rhizosphere development and corresponding increases in C inputs. δ13C values of all PLFAs decreased with time following woody encroachment, indicating assimilation of woodland C sources. Among the microbial groups, fungi and actinobacteria in woodland soils selectively assimilated grassland C to a greater extent than its contribution to bulk soil. Between the two woodland types, microbes in the groves incorporated relatively more of the relict C4-C than those in the clusters, potentially due to differences in below ground plant C allocation and organo-mineral association. Changes in plant productivity and C accessibility (rather than C chemistry) dictated microbial C utilization in this system in response to shrub encroachment.

  6. Successful range-expanding plants experience less above-ground and below-ground enemy impact.

    Science.gov (United States)

    Engelkes, Tim; Morriën, Elly; Verhoeven, Koen J F; Bezemer, T Martijn; Biere, Arjen; Harvey, Jeffrey A; McIntyre, Lauren M; Tamis, Wil L M; van der Putten, Wim H

    2008-12-18

    Many species are currently moving to higher latitudes and altitudes. However, little is known about the factors that influence the future performance of range-expanding species in their new habitats. Here we show that range-expanding plant species from a riverine area were better defended against shoot and root enemies than were related native plant species growing in the same area. We grew fifteen plant species with and without non-coevolved polyphagous locusts and cosmopolitan, polyphagous aphids. Contrary to our expectations, the locusts performed more poorly on the range-expanding plant species than on the congeneric native plant species, whereas the aphids showed no difference. The shoot herbivores reduced the biomass of the native plants more than they did that of the congeneric range expanders. Also, the range-expanding plants developed fewer pathogenic effects in their root-zone soil than did the related native species. Current predictions forecast biodiversity loss due to limitations in the ability of species to adjust to climate warming conditions in their range. Our results strongly suggest that the plants that shift ranges towards higher latitudes and altitudes may include potential invaders, as the successful range expanders may experience less control by above-ground or below-ground enemies than the natives.

  7. Above- and Belowground Biomass Models for Trees in the Miombo Woodlands of Malawi

    Directory of Open Access Journals (Sweden)

    Daud J. Kachamba

    2016-02-01

    Full Text Available In this study we present general (multiple tree species from several sites above- and belowground biomass models for trees in the miombo woodlands of Malawi. Such models are currently lacking in the country. The modelling was based on 74 trees comprising 33 different species with diameters at breast height (dbh and total tree height (ht ranging from 5.3 to 2 cm and from 3.0 to 25.0 m, respectively. Trees were collected from four silvicultural zones covering a wide range of conditions. We tested different models including dbh, ht and wood specific gravity ( ρ as independent variables. We evaluated model performance using pseudo-R2, root mean square error (RMSE, a covariance matrix for the parameter estimates, mean prediction error (MPE and relative mean prediction error (MPE%. Computation of MPE% was based on leave-one-out cross-validation. Values of pseudo-R2 and MPE% ranged 0.82–0.97 and 0.9%–2.8%, respectively. Model performance indicated that the models can be used over a wide range of geographical and ecological conditions in Malawi.

  8. Plant genotypes affect aboveground and belowground herbivore interactions by changing chemical defense.

    Science.gov (United States)

    Li, Xiaoqiong; Guo, Wenfeng; Siemann, Evan; Wen, Yuanguang; Huang, Wei; Ding, Jianqing

    2016-12-01

    Spatially separated aboveground (AG) and belowground (BG) herbivores are closely linked through shared host plants, and both patterns of AG-BG interactions and plant responses may vary among plant genotypes. We subjected invasive (USA) and native (China) genotypes of tallow tree (Triadica sebifera) to herbivory by the AG specialist leaf-rolling weevil Heterapoderopsis bicallosicollis and/or the root-feeding larvae of flea beetle Bikasha collaris. We measured leaf damage and leaves rolled by weevils, quantified beetle survival, and analyzed flavonoid and tannin concentrations in leaves and roots. AG and BG herbivores formed negative feedbacks on both native and invasive genotypes. Leaf damage by weevils and the number of beetle larvae emerging as adults were higher on invasive genotypes. Beetles reduced weevil damage and weevils reduced beetle larval emergence more strongly for invasive genotypes. Invasive genotypes had lower leaf and root tannins than native genotypes. BG beetles decreased leaf tannins of native genotypes but increased root tannins of invasive genotypes. AG herbivory increased root flavonoids of invasive genotypes while BG herbivory decreased leaf flavonoids. Invasive genotypes had lower AG and BG herbivore resistance, and negative AG-BG herbivore feedbacks were much stronger for invasive genotypes. Lower tannin concentrations explained overall better AG and BG herbivore performances on invasive genotypes. However, changes in tannins and flavonoids affected AG and BG herbivores differently. These results suggest that divergent selection on chemical production in invasive plants may be critical in regulating herbivore performances and novel AG and BG herbivore communities in new environments.

  9. A global Fine-Root Ecology Database to address below-ground challenges in plant ecology.

    Science.gov (United States)

    Iversen, Colleen M; McCormack, M Luke; Powell, A Shafer; Blackwood, Christopher B; Freschet, Grégoire T; Kattge, Jens; Roumet, Catherine; Stover, Daniel B; Soudzilovskaia, Nadejda A; Valverde-Barrantes, Oscar J; van Bodegom, Peter M; Violle, Cyrille

    2017-07-01

    Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time. © 2017 UT-Battelle LLC. New Phytologist © 2017 New Phytologist Trust.

  10. Picturing Adoption of Below-Ground Biodiversity Technologies among Smallholder Farmers around Mabira Forest, Uganda

    Directory of Open Access Journals (Sweden)

    Isabirye, BE.

    2010-01-01

    Full Text Available Faced with a multitude of soil and water amendment technologies, farmers have the task of choosing the technologies to adopt for ensuring subsistence and income sustainability. In 2008, a study to characterize the farmers was conducted around Mabira Forest, to assess the adoption of soil technologies fostering Belowground Biodiversity (BGBD. Eighty-four households (38 participating and 46 non-participants from four villages were randomly selected and interviewed. Results showed that the adoption pattern was significantly driven by farm size, labor, household size, age and wealth status of the house. Also important were farm location, gender of household head, primary occupation, soil and water conservation technologies training, land tenure, and social capital. For the few current adopters, there was a perceived increase in labor demand but overall productivity was higher, partly resulting from increased crop productivity due to soil fertility enhancement and soil structure modification. It is therefore concluded that, around Mabira forest, BGBD technologies will be adopted by farming households with sufficient land, labor and social capital.

  11. Aboveground endophyte affects root volatile emission and host plant selection of a belowground insect.

    Science.gov (United States)

    Rostás, Michael; Cripps, Michael G; Silcock, Patrick

    2015-02-01

    Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.

  12. Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

    Science.gov (United States)

    Meier, Courtney L; Bowman, William D

    2008-12-16

    Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

  13. Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

    Directory of Open Access Journals (Sweden)

    Loïc ePellissier

    2013-12-01

    Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

  14. Managing carbon sequestration and storage in northern hardwood forests

    Science.gov (United States)

    Eunice A. Padley; Deahn M. Donner; Karin S. Fassnacht; Ronald S. Zalesny; Bruce Birr; Karl J. Martin

    2011-01-01

    Carbon has an important role in sustainable forest management, contributing to functions that maintain site productivity, nutrient cycling, and soil physical properties. Forest management practices can alter ecosystem carbon allocation as well as the amount of total site carbon.

  15. Global scale analysis and evaluation of an improved mechanistic representation of plant nitrogen and carbon dynamics in the Community Land Model (CLM)

    Science.gov (United States)

    Ghimire, B.; Riley, W. J.; Koven, C. D.; Randerson, J. T.; Mu, M.; Kattge, J.; Rogers, A.; Reich, P. B.

    2014-12-01

    mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers leads to overall improvements in CLM4.5's global carbon cycling predictions.

  16. Learning and strategic asset allocation

    OpenAIRE

    Kearns, Michael

    2016-01-01

    This thesis investigates whether or not models that portray the relationship between what an investor learns and how he allocates his portfolio can explain phenomena related to household behaviour in the stock market. Endogenous modelling of household learning is utilised, which builds on a growing literature called bounded rationality with increasing explanatory power, offering an alternative to the classical rational expectations theory. Such phenomena include firstly why households often h...

  17. Resource allocation in networks via coalitional games

    NARCIS (Netherlands)

    Shams, F.

    2016-01-01

    The main goal of this dissertation is to manage resource allocation in network engineering problems and to introduce efficient cooperative algorithms to obtain high performance, ensuring fairness and stability. Specifically, this dissertation introduces new approaches for resource allocation in

  18. Integrating the Carbon and Water Footprints’ Costs in the Water Framework Directive 2000/60/EC Full Water Cost Recovery Concept: Basic Principles Towards Their Reliable Calculation and Socially Just Allocation

    Directory of Open Access Journals (Sweden)

    Anastasia Papadopoulou

    2012-01-01

    Full Text Available This paper presents the basic principles for the integration of the water and carbon footprints cost into the resource and environmental costs respectively, taking the suggestions set by the Water Framework Directive (WFD 2000/60/EC one step forward. WFD states that full water cost recovery (FWCR should be based on the estimation of the three sub-costs related: direct; environmental; and resource cost. It also strongly suggests the EU Member States develop and apply effective water pricing policies to achieve FWCR. These policies must be socially just to avoid any social injustice phenomena. This is a very delicate task to handle, especially within the fragile economic conditions that the EU is facing today. Water losses play a crucial role for the FWC estimation. Water losses should not be neglected since they are one of the major “water uses” in any water supply network. A methodology is suggested to reduce water losses and the related Non Revenue Water (NRW index. An Expert Decision Support System is proposed to assess the FWC incorporating the Water and Carbon Footprint costs.

  19. Asset Allocation of Mutual Fund Investors

    OpenAIRE

    Dengpan Luo

    2003-01-01

    This paper studies mutual fund investors' asset allocation decisions using monthly flow data of U.S mutual fund industry from 1984 to 1998. We find that mutual fund investors change their asset allocations between stocks and bonds in reaction to business conditions tracked by changes in expected stock market returns. They tend to allocate less into stock funds during the trough of a business cycle when expected stock market returns are higher and to allocate more into stock funds during the p...

  20. Optimal resource allocation for distributed video communication

    CERN Document Server

    He, Yifeng

    2013-01-01

    While most books on the subject focus on resource allocation in just one type of network, this book is the first to examine the common characteristics of multiple distributed video communication systems. Comprehensive and systematic, Optimal Resource Allocation for Distributed Video Communication presents a unified optimization framework for resource allocation across these systems. The book examines the techniques required for optimal resource allocation over Internet, wireless cellular networks, wireless ad hoc networks, and wireless sensor networks. It provides you with the required foundat

  1. How emission certificate allocations distort fossil investments: The German example

    International Nuclear Information System (INIS)

    Pahle, Michael; Fan Lin; Schill, Wolf-Peter

    2011-01-01

    Despite political activities to foster a low-carbon energy transition, Germany currently sees a considerable number of new coal power plants being added to its power mix. There are several possible drivers for this 'dash for coal', but it is widely accepted that windfall profits gained through free allocation of ETS certificates play an important role. Yet the quantification of allocation-related investment distortions has been limited to back-of-the envelope calculations and stylized models so far. We close this gap with a numerical model integrating both Germany's particular allocation rules and its specific power generation structure. We find that technology specific new entrant provisions have substantially increased incentives to invest in hard coal plants red to natural gas at the time of the ETS onset. More precisely, disproportionate windfall profits compared more than half the total capital costs of a hard coal plant. Moreover, shorter periods of free allocations would not have turned investors' favours towards the cleaner natural gas technology because of pre-existing economic advantages for coal. In contrast, full auctioning of permits or a single best available technology benchmark would have made natural gas the predominant technology of choice. - Research highlights: → We study how early emission certificate allocations in Germany distort fossil investments. → We examine the role of windfall profits in the overall profitabilities of a new hard coal compared to a natural gas plant. → We find that technology specific grandfathering over any period does not induce a change in preferences away from hard coal. → Natural gas would have been preferred under auctioning or a technology neutral allocation though.

  2. Intelligent tactical asset allocation support system

    NARCIS (Netherlands)

    Hiemstra, Y.

    1995-01-01

    This paper presents an advanced support system for Tactical Asset Allocation. Asset allocation explains over 90% of portfolio performance (Brinson, Hood and Beebower, 1988). Tactical asset allocation adjusts a strategic portfolio on the basis of short term market outlooks. The system includes

  3. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Science.gov (United States)

    Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  4. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    Science.gov (United States)

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

  5. Environmental Metabarcoding Reveals Contrasting Belowground and Aboveground Fungal Communities from Poplar at a Hg Phytomanagement Site.

    Science.gov (United States)

    Durand, Alexis; Maillard, François; Foulon, Julie; Gweon, Hyun S; Valot, Benoit; Chalot, Michel

    2017-11-01

    Characterization of microbial communities in stressful conditions at a field level is rather scarce, especially when considering fungal communities from aboveground habitats. We aimed at characterizing fungal communities from different poplar habitats at a Hg-contaminated phytomanagement site by using Illumina-based sequencing, network analysis approach, and direct isolation of Hg-resistant fungal strains. The highest diversity estimated by the Shannon index was found for soil communities, which was negatively affected by soil Hg concentration. Among the significant correlations between soil operational taxonomic units (OTUs) in the co-occurrence network, 80% were negatively correlated revealing dominance of a pattern of mutual exclusion. The fungal communities associated with Populus roots mostly consisted of OTUs from the symbiotic guild, such as members of the Thelephoraceae, thus explaining the lowest diversity found for root communities. Additionally, root communities showed the highest network connectivity index, while rarely detected OTUs from the Glomeromycetes may have a central role in the root network. Unexpectedly high richness and diversity were found for aboveground habitats, compared to the root habitat. The aboveground habitats were dominated by yeasts from the Lalaria, Davidiella, and Bensingtonia genera, not detected in belowground habitats. Leaf and stem habitats were characterized by few dominant OTUs such as those from the Dothideomycete class producing mutual exclusion with other OTUs. Aureobasidium pullulans, one of the dominating OTUs, was further isolated from the leaf habitat, in addition to Nakazawaea populi species, which were found to be Hg resistant. Altogether, these findings will provide an improved point of reference for microbial research on inoculation-based programs of tailings dumps.

  6. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Paudel, Shishir; Longcore, Travis; MacDonald, Beau; McCormick, Melissa K; Szlavecz, Katalin; Wilson, Gail W T; Loss, Scot R

    2016-03-01

    A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms' effects on AMF and (2) the factors that determine the outcomes of earthworm-AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant-AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

  7. Tradable permit allocations and sequential choice

    Energy Technology Data Exchange (ETDEWEB)

    MacKenzie, Ian A. [Centre for Economic Research, ETH Zuerich, Zurichbergstrasse 18, 8092 Zuerich (Switzerland)

    2011-01-15

    This paper investigates initial allocation choices in an international tradable pollution permit market. For two sovereign governments, we compare allocation choices that are either simultaneously or sequentially announced. We show sequential allocation announcements result in higher (lower) aggregate emissions when announcements are strategic substitutes (complements). Whether allocation announcements are strategic substitutes or complements depends on the relationship between the follower's damage function and governments' abatement costs. When the marginal damage function is relatively steep (flat), allocation announcements are strategic substitutes (complements). For quadratic abatement costs and damages, sequential announcements provide a higher level of aggregate emissions. (author)

  8. Optimal allocation of leaf epidermal area for gas exchange.

    Science.gov (United States)

    de Boer, Hugo J; Price, Charles A; Wagner-Cremer, Friederike; Dekker, Stefan C; Franks, Peter J; Veneklaas, Erik J

    2016-06-01

    A long-standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of diffusion and geometry based on the hypothesis that selection for higher anatomical maximum stomatal conductance (gsmax ) involves a trade-off to minimize the fraction of the epidermis that is allocated to stomata. Predicted allometric relationships between stomatal traits were tested with a comprehensive compilation of published and unpublished data on 1057 species from all major clades. In support of our theoretical framework, stomatal traits of this phylogenetically diverse sample reflect spatially optimal allometry that minimizes investment in the allocation of epidermal area when plants evolve towards higher gsmax . Our results specifically highlight that the stomatal morphology of angiosperms evolved along spatially optimal allometric relationships. We propose that the resulting wide range of viable stomatal trait combinations equips angiosperms with developmental and evolutionary flexibility in leaf gas exchange unrivalled by gymnosperms and pteridophytes. © 2016 The Authors New Phytologist © 2016 New Phytologist Trust.

  9. Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States

    Science.gov (United States)

    Matthew B. Russell; Grant M. Domke; Christopher W. Woodall; Anthony W. D' Amato

    2015-01-01

    Background: Refined estimation of carbon (C) stocks within forest ecosystems is a critical component of efforts to reduce greenhouse gas emissions and mitigate the effects of projected climate change through forest C management. Specifically, belowground C stocks are currently estimated in the United States' national greenhouse gas inventory (US NGHGI) using...

  10. Impacts of forest harvest on active carbon and microbial properties of a volcanic ash cap soil in northern Idaho

    Science.gov (United States)

    Deborah S. Page-Dumroese; Matt D. Busse; Steven T. Overby; Brian D. Gardner; Joanne M. Tirocke

    2015-01-01

    Soil quality assessments are essential for determining impacts on belowground microbial community structure and function. We evaluated the suitability of active carbon (C), a rapid field test, as an indicator of soil biological quality in five paired forest stands (clear cut harvested 40 years prior and unharvested) growing on volcanic ash-cap soils in northern Idaho....

  11. Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly stands

    Science.gov (United States)

    Kurt H. Johnsen; Lisa J. Samuelson; Felipe G. Sanchez; Bob Eaton

    2013-01-01

    Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating...

  12. High yielding biomass genotypes of willow (Salix spp.) show differences in below ground biomass allocation

    International Nuclear Information System (INIS)

    Cunniff, Jennifer; Purdy, Sarah J.; Barraclough, Tim J.P.; Castle, March; Maddison, Anne L.; Jones, Laurence E.; Shield, Ian F.; Gregory, Andrew S.; Karp, Angela

    2015-01-01

    Willows (Salix spp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation. - Highlights: • SRC willows are a source of biomass and act as carbon (C) sinks. • Biomass allocation was measured in 4 willow genotypes grown in two UK field sites. • The greatest yielding genotype had the greatest below ground biomass at both sites. • Below ground biomass allocation differed by up to 10% between genotypes and 94% between sites. • Environment e.g. wind

  13. Cost allocation review : staff discussion paper

    International Nuclear Information System (INIS)

    2005-09-01

    This report addressed the need for updated cost allocation studies filed by local electricity distribution companies because they ensure that distribution rates for each customer class remain just and reasonable. According to the 2001 Electricity Distribution Rate Handbook, the Ontario Energy Board requires new cost allocation studies before implementing any future incentive regulation plans. A review of cost allocations allows the Board to consider the need for adjustments to the current share of distribution costs paid by different classes of ratepayers. This report included 14 sections to facilitate consultations with stakeholders on financial information requirements for cost allocation; directly assignable costs; functionalization; categorization; allocation methods; allocation of other costs; load data requirements; cost allocation implementation issues; addition of new rate class and rate design for scattered unmetered loads; addition of new rate class for larger users; rates to charge embedded distributors; treatment of the rate sub-classification identified as time-of-use; and, rate design implementation issues. 1 fig., 7 appendices

  14. Public Interest vs. Interest Groups: Allowance Allocation in the EU Emission Trading Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Anger, Niels; Oberndorfer, Ulrich (Centre for European Economic Research, Mannheim (Germany)); Boehringer, Christoph (Carl von Ossietzky Univ., Oldenburg (Germany))

    2008-07-01

    We assess the political-economy determinants of allowance allocation in the EU Emissions Trading Scheme (EU ETS). A common-agency model suggests that the government considers the preferences of sectoral interest groups when allocating emissions permits, so that industries with a more powerful lobby face a lower regulatory burden. An empirical analysis of the first trading phase of the EU ETS corroborates our theoretical prediction, but also reveals that the political-economy determinants of permit allocation are more complex. Employing instrumental-variable estimation technique, we find that large carbon emitters that were represented by powerful interest groups received higher levels of emissions allowances

  15. Overview of the physiological ecology of carbon metabolism in seagrasses.

    Science.gov (United States)

    Touchette; Burkholder

    2000-07-30

    The small but diverse group of angiosperms known as seagrasses form submersed meadow communities that are among the most productive on earth. Seagrasses are frequently light-limited and, despite access to carbon-rich seawaters, they may also sustain periodic internal carbon limitation. They have been regarded as C3 plants, but many species appear to be C3-C4 intermediates and/or have various carbon-concentrating mechanisms to aid the Rubisco enzyme in carbon acquisition. Photorespiration can occur as a C loss process that may protect photosynthetic electron transport during periods of low CO(2) availability and high light intensity. Seagrasses can also become photoinhibited in high light (generally>1000 µE m(-2) s(-1)) as a protective mechanism that allows excessive light energy to be dissipated as heat. Many photosynthesis-irradiance curves have been developed to assess light levels needed for seagrass growth. However, most available data (e.g. compensation irradiance I(c)) do not account for belowground tissue respiration and, thus, are of limited use in assessing the whole-plant carbon balance across light gradients. Caution is recommended in use of I(k) (saturating irradiance for photosynthesis), since seagrass photosynthesis commonly increases under higher light intensities than I(k); and in estimating seagrass productivity from H(sat) (duration of daily light period when light equals or exceeds I(k)) which varies considerably among species and sites, and which fails to account for light-limited photosynthesis at light levels less than I(k). The dominant storage carbohydrate in seagrasses is sucrose (primarily stored in rhizomes), which generally forms more than 90% of the total soluble carbohydrate pool. Seagrasses with high I(c) levels (suggesting lower efficiency in C acquisition) have relatively low levels of leaf carbohydrates. Sucrose-P synthase (SPS, involved in sucrose synthesis) activity increases with leaf age, consistent with leaf maturation from

  16. Allocation decisions in network industries

    Energy Technology Data Exchange (ETDEWEB)

    Bolle, Friedel [Europa-Universitaet Viadrina Frankfurt, Lehrstuhl Volkswirtschaftslehre, insbesondere Wirtschaftstheorie (Mikrooekonomie), Postfach 1786 15207 Frankfurt (Germany)

    2008-01-15

    In this paper, I want to propagate a new analytical tool: The usage of Menu Auctions for modelling complicated auctions, negotiations, rent seeking, etc. is advocated, because, contrary to 'normal' auctions and bargaining models, an arbitrary number of additional aspects can be taken into account. After concentrating on 'Truthful Equilibria' [Bernheim, B.D., Whinston, M.D., 1986. Menu auctions, resource allocation, and economic influence, Quarterly Journal of Economics, 1-31.] a certain broad class of Menu Auctions show unique and efficient allocations. Under an additional concavity condition even the equilibrium bids are unique. Two examples are discussed: the privatisation of a state-owned industry and the buying of wholesale electricity (concluding contracts with a number of producers) by a utility. These examples also serve to trace the sources of 'non-concavities' which can prevent the uniqueness of bids and can provide the auctioneer with incentives to exclude bidders from the competition. (author)

  17. Allocation - the Howe measurement challenges

    Energy Technology Data Exchange (ETDEWEB)

    Tierney, Jim; Moksnes, Paul Ove

    2005-07-01

    The Howe Field is located in the Central North Sea Block 22/12a approximately 160 km east of Aberdeen in a water depth of 85 m. The reservoir lies some 12 km east of the Shell operated Nelson Platform, which is situated in adjacent Block 22/11. The Howe project was initiated by Shell Exploration and Production to augment the operating life and production capacity of the Nelson platform, involving the development of an additional subset infrastructure and the installation of topside facilities. The owners of the Howe Field are Enterprise Oil PLC , Intrepid Energy and OMV. The Howe well fluids are commingled with Nelson fluids. Therefore, it is required to measure the Howe well fluids to differentiate between the fields and to determine how much money each partner is allocated. The commercial agreements have stipulated that the measurements of Howe fluids are required to be measured within an accuracy of +- 5% of reading. In addition to accuracy constraints, it was important to minimise capex to ensure the development was economically viable. Given this, multiphase metering was considered to be a solution for allocation between the different ownerships, as opposed to traditional separator metering. This paper will present the journey of the project activity through the selection criteria, flow loop test, installation, commissioning and the first 3 months of operation of the MPFM including verification with the Nelson test separator. Detailing with careful management and engineering support how to succeed with this type of application. (author) (tk)

  18. Vegetation in karst terrain of southwestern China allocates more biomass to roots

    Science.gov (United States)

    Ni, J.; Luo, D. H.; Xia, J.; Zhang, Z. H.; Hu, G.

    2015-07-01

    In mountainous areas of southwestern China, especially Guizhou province, continuous, broadly distributed karst landscapes with harsh and fragile habitats often lead to land degradation. Research indicates that vegetation located in karst terrains has low aboveground biomass and land degradation that reduces vegetation biomass, but belowground biomass measurements are rarely reported. Using the soil pit method, we investigated the root biomass of karst vegetation in five land cover types: grassland, grass-scrub tussock, thorn-scrub shrubland, scrub-tree forest, and mixed evergreen and deciduous forest in Maolan, southern Guizhou province, growing in two different soil-rich and rock-dominated habitats. The results show that roots in karst vegetation, especially the coarse roots, and roots in rocky habitats are mostly distributed in the topsoil layers (89 % on the surface up to 20 cm depth). The total root biomass in all habitats of all vegetation degradation periods is 18.77 Mg ha-1, in which roots in rocky habitat have higher biomass than in earthy habitat, and coarse root biomass is larger than medium and fine root biomass. The root biomass of mixed evergreen and deciduous forest in karst habitat (35.83 Mg ha-1) is not greater than that of most typical, non-karst evergreen broad-leaved forests in subtropical regions of China, but the ratio of root to aboveground biomass in karst forest (0.37) is significantly greater than the mean ratio (0.26 ± 0.07) of subtropical evergreen forests. Vegetation restoration in degraded karst terrain will significantly increase the belowground carbon stock, forming a potential regional carbon sink.

  19. Soil respiration in Tibetan alpine grasslands: belowground biomass and soil moisture, but not soil temperature, best explain the large-scale patterns.

    Directory of Open Access Journals (Sweden)

    Yan Geng

    Full Text Available The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1 belowground biomass (BGB is most closely related to spatial variation in Rs due to high root biomass density, and (2 soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO(2 m(-2 s(-1, ranging from 0.39 to 12.88 µmol CO(2 m(-2 s(-1, with average daily mean Rs of 2.01 and 5.49 µmol CO(2 m(-2 s(-1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB, SOC, soil moisture (SM, and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80% of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82% of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.

  20. No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

    Science.gov (United States)

    Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

    2017-06-17

    Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

  1. Belowground uptake strategies: how fine-root traits determine tree growth

    NARCIS (Netherlands)

    Weemstra, Monique

    2017-01-01

    The growth of trees depends on photosynthetic carbon gain by the leaves, which in turn relies on water and nutrient acquisition by the fine roots. Because the availability of carbon, water and nutrients fluctuates, trees can adjust their leaf and fine-root functional traits to maintain their

  2. Transmission usage cost allocation schemes

    International Nuclear Information System (INIS)

    Abou El Ela, A.A.; El-Sehiemy, R.A.

    2009-01-01

    This paper presents different suggested transmission usage cost allocation (TCA) schemes to the system individuals. Different independent system operator (ISO) visions are presented using the proportional rata and flow-based TCA methods. There are two proposed flow-based TCA schemes (FTCA). The first FTCA scheme generalizes the equivalent bilateral exchanges (EBE) concepts for lossy networks through two-stage procedure. The second FTCA scheme is based on the modified sensitivity factors (MSF). These factors are developed from the actual measurements of power flows in transmission lines and the power injections at different buses. The proposed schemes exhibit desirable apportioning properties and are easy to implement and understand. Case studies for different loading conditions are carried out to show the capability of the proposed schemes for solving the TCA problem. (author)

  3. Belowground Response to Drought in a Tropical Forest Soil. II. Change in Microbial Function Impacts Carbon Composition

    Science.gov (United States)

    Nicholas J. Bouskill; Tana E. Wood; Richard Baran; Zhao Hao; Zaw Ye; Ben P. Bowen; Hsiao Chien Lim; Peter S. Nico; Hoi-Ying Holman; Benjamin Gilbert; Whendee L. Silver; Trent R. Northen; Eoin L. Brodie

    2016-01-01

    Climate model projections for tropical regions show clear perturbation of precipitation patterns leading to increased frequency and severity of drought in some regions. Previous work has shown declining soil moisture to be a strong driver of changes in microbial trait distribution, however...

  4. Soil Respiration and Belowground Carbon Stores Among Salt Marshes Subjected to Increasing Watershed Nitrogen Loadings in Southern New England

    Science.gov (United States)

    Coastal salt marshes are ecosystems located between the uplands and sea, and because of their location are subject to increasing watershed nutrient loadings and rising sea levels. Residential development along the coast is intense, and there is a significant relationship between...

  5. Intelligent tactical asset allocation support system

    OpenAIRE

    Hiemstra, Y.

    1995-01-01

    This paper presents an advanced support system for Tactical Asset Allocation. Asset allocation explains over 90% of portfolio performance (Brinson, Hood and Beebower, 1988). Tactical asset allocation adjusts a strategic portfolio on the basis of short term market outlooks. The system includes aprediction model that forecasts quarterly excess returns on the S and PSOO, an optimization model that adjusts a user-specified strategic portfolio on thebasis of the excess return forecast, and a compo...

  6. Belowground neighbor perception in Arabidopsis thaliana studied by transcriptome analysis: roots of Hieracium pilosella cause biotic stress

    Directory of Open Access Journals (Sweden)

    Christoph eSchmid

    2013-08-01

    Full Text Available Root-root interactions are much more sophisticated than previously thought, yet the mechanisms of belowground neighbor perception remain largely obscure. Genome-wide transcriptome analyses allow detailed insight into plant reactions to environmental cues.A root interaction trial was set up to explore both morphological and whole genome transcriptional responses in roots of Arabidopsis thaliana in the presence or absence of an inferior competitor, Hieracium pilosella.Neighbor perception was indicated by Arabidopsis roots predominantly growing away from the neighbor (segregation, while solitary plants placed more roots towards the middle of the pot. Total biomass remained unaffected. Database comparisons in transcriptome analysis revealed considerable similarity between Arabidopsis root reactions to neighbors and reactions to pathogens. Detailed analyses of the functional category ‘biotic stress’ using MapMan tools found the sub-category ‘pathogenesis-related proteins’ highly significantly induced. A comparison to a study on intraspecific competition brought forward a core of genes consistently involved in reactions to neighbor roots.We conclude that beyond resource depletion roots perceive neighboring roots or their associated microorganisms by a relatively uniform mechanism that involves the strong induction of pathogenesis-related proteins. In an ecological context the findings reveal that belowground neighbor detection may occur independently of resource depletion, allowing for a time advantage for the root to prepare for potential interactions.

  7. An intelligent allocation algorithm for parallel processing

    Science.gov (United States)

    Carroll, Chester C.; Homaifar, Abdollah; Ananthram, Kishan G.

    1988-01-01

    The problem of allocating nodes of a program graph to processors in a parallel processing architecture is considered. The algorithm is based on critical path analysis, some allocation heuristics, and the execution granularity of nodes in a program graph. These factors, and the structure of interprocessor communication network, influence the allocation. To achieve realistic estimations of the executive durations of allocations, the algorithm considers the fact that nodes in a program graph have to communicate through varying numbers of tokens. Coarse and fine granularities have been implemented, with interprocessor token-communication duration, varying from zero up to values comparable to the execution durations of individual nodes. The effect on allocation of communication network structures is demonstrated by performing allocations for crossbar (non-blocking) and star (blocking) networks. The algorithm assumes the availability of as many processors as it needs for the optimal allocation of any program graph. Hence, the focus of allocation has been on varying token-communication durations rather than varying the number of processors. The algorithm always utilizes as many processors as necessary for the optimal allocation of any program graph, depending upon granularity and characteristics of the interprocessor communication network.

  8. Cognitive radio networks dynamic resource allocation schemes

    CERN Document Server

    Wang, Shaowei

    2014-01-01

    This SpringerBrief presents a survey of dynamic resource allocation schemes in Cognitive Radio (CR) Systems, focusing on the spectral-efficiency and energy-efficiency in wireless networks. It also introduces a variety of dynamic resource allocation schemes for CR networks and provides a concise introduction of the landscape of CR technology. The author covers in detail the dynamic resource allocation problem for the motivations and challenges in CR systems. The Spectral- and Energy-Efficient resource allocation schemes are comprehensively investigated, including new insights into the trade-off

  9. Carbon dioxide flux measurements from a coastal Douglas-fir forest floor

    International Nuclear Information System (INIS)

    Drewitt, G.B.

    2002-01-01

    This thesis examined the process that affects the exchange of carbon between the soil and the atmosphere with particular attention to the large amounts of carbon stored in soils in the form of decaying organic matter. This forest floor measuring study was conducted in 2000 at a micro-meteorological tower flux site in a coastal temperature Douglas-fir forest. The measuring study involved half hourly measurements of both carbon dioxide and below-ground carbon dioxide storage. Measurements were taken at 6 locations between April and December to include a large portion of the growing season. Eddy covariance (EC) measurements of carbon dioxide flux above the forest floor over a two month period in the summer and the autumn were compared with forest floor measurements. Below-ground carbon dioxide mixing ratios of soil air were measured at 6 depths between 0.02 to 1 m using gas diffusion probes and a syringe sampling method. Maximum carbon dioxide fluxes measured by the soil chambers varied by a factor of 3 and a high spatial variability in soil carbon dioxide flux was noted. Forest floor carbon dioxide fluxes measured by each of the chambers indicated different sensitivities to soil temperature. Hysteresis in the flux temperature relationship over the year was evident. Reliable below-canopy EC measurements of the forest floor carbon dioxide flux were difficult to obtain because of the every low wind speeds below the forest canopy. The amount of carbon dioxde present in the soil increased rapidly with depth near the surface but less rapidly deeper in the soil. It was suggested that approximately half of the carbon dioxide produced below-ground comes from between the soil surface and the first 0.15 m of depth. Carbon dioxide fluxes from the floor of a Douglas-fir forest were found to be large compared to other, less productive ecosystems

  10. Old-growth forests can accumulate carbon in soils

    Science.gov (United States)

    Zhou, G.; Liu, S.; Li, Z.; Zhang, Dongxiao; Tang, X.; Zhou, C.; Yan, J.; Mo, J.

    2006-01-01

    Old-growth forests have traditionally been considered negligible as carbon sinks because carbon uptake has been thought to be balanced by respiration. We show that the top 20-centimeter soil layer in preserved old-growth forests in southern China accumulated atmospheric carbon at an unexpectedly high average rate of 0.61 megagrams of carbon hectare-1 year-1 from 1979 to 2003. This study suggests that the carbon cycle processes in the belowground system of these forests are changing in response to the changing environment. The result directly challenges the prevailing belief in ecosystem ecology regarding carbon budget in old-growth forests and supports the establishment of a new, nonequilibrium conceptual framework to study soil carbon dynamics.

  11. The carbon-sequestration potential of a global afforestation program

    International Nuclear Information System (INIS)

    Nilsson, S.; Schopfhauser, W.

    1995-01-01

    The authors analyzed the changes in the carbon cycle that could be achieved with a global large-scale afforestation program that is economically, politically and technically feasible. They estimated that of the areas regarded as suitable for large-scale plantations, only about 345 million ha would actually be available for plantations and agroforestry for the sole purpose of sequestering carbon. The maximum annual rate of carbon fixation (1.48 Gt/yr) would only be achieved 60 years after the establishment of the plantation - 1.14 Gt by above-ground biomass and 0.34 Gt by below-ground biomass. Over the periods from 1995 to 2095, a total of 104 Gt of carbon would be sequestered. This is substantially lower than the amount of carbon required to offset current carbon emissions (3.8 Gt/yr) in order to stabilize the carbon content of the atmosphere. 108 refs., 1 fig., 14 tabs

  12. Peer-Allocated Instant Response (PAIR): Computional allocation of peer tutors in learning communities

    NARCIS (Netherlands)

    Westera, Wim

    2009-01-01

    Westera, W. (2007). Peer-Allocated Instant Response (PAIR): Computational allocation of peer tutors in learning communities. Journal of Artificial Societies and Social Simulation, http://jasss.soc.surrey.ac.uk/10/2/5.html

  13. Interactive effects of elevated CO2 and nitrogen deposition on fatty acid molecular and isotope composition of above- and belowground tree biomass and forest soil fractions.

    Science.gov (United States)

    Griepentrog, Marco; Eglinton, Timothy I; Hagedorn, Frank; Schmidt, Michael W I; Wiesenberg, Guido L B

    2015-01-01

    Atmospheric carbon dioxide (CO2) and reactive nitrogen (N) concentrations have been increasing due to human activities and impact the global carbon (C) cycle by affecting plant photosynthesis and decomposition processes in soil. Large amounts of C are stored in plants and soils, but the mechanisms behind the stabilization of plant- and microbial-derived organic matter (OM) in soils are still under debate and it is not clear how N deposition affects soil OM dynamics. Here, we studied the effects of 4 years of elevated (13C-depleted) CO2 and N deposition in forest ecosystems established in open-top chambers on composition and turnover of fatty acids (FAs) in plants and soils. FAs served as biomarkers for plant- and microbial-derived OM in soil density fractions. We analyzed above- and belowground plant biomass of beech and spruce trees as well as soil density fractions for the total organic C and FA molecular and isotope (δ13C) composition. FAs did not accumulate relative to total organic C in fine mineral fractions, showing that FAs are not effectively stabilized by association with soil minerals. The δ13C values of FAs in plant biomass increased under high N deposition. However, the N effect was only apparent under elevated CO2 suggesting a N limitation of the system. In soil fractions, only isotope compositions of short-chain FAs (C16+18) were affected. Fractions of 'new' (experimental-derived) FAs were calculated using isotope depletion in elevated CO2 plots and decreased from free light to fine mineral fractions. 'New' FAs were higher in short-chain compared to long-chain FAs (C20-30), indicating a faster turnover of short-chain compared to long-chain FAs. Increased N deposition did not significantly affect the quantity of 'new' FAs in soil fractions, but showed a tendency of increased amounts of 'old' (pre-experimental) C suggesting that decomposition of 'old' C is retarded by high N inputs. © 2014 John Wiley & Sons Ltd.

  14. Time allocation of disabled individuals.

    Science.gov (United States)

    Pagán, Ricardo

    2013-05-01

    Although some studies have analysed the disability phenomenon and its effect on, for example, labour force participation, wages, job satisfaction, or the use of disability pension, the empirical evidence on how disability steals time (e.g. hours of work) from individuals is very scarce. This article examines how disabled individuals allocate their time to daily activities as compared to their non-disabled counterparts. Using time diary information from the Spanish Time Use Survey (last quarter of 2002 and the first three quarters of 2003), we estimate the determinants of time (minutes per day) spent on four aggregate categories (market work, household production, tertiary activities and leisure) for a sample of 27,687 non-disabled and 5250 disabled individuals and decompose the observed time differential by using the Oaxaca-Blinder methodology. The results show that disabled individuals devote less time to market work (especially females), and more time to household production (e.g. cooking, cleaning, child care), tertiary activities (e.g., sleeping, personal care, medical treatment) and leisure activities. We also find a significant effect of age on the time spent on daily activities and important differences by gender and disability status. The results are consistent with the hypothesis that disability steals time, and reiterate the fact that more public policies are needed to balance working life and health concerns among disabled individuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Multiobjective optimal allocation problem with probabilistic non ...

    African Journals Online (AJOL)

    user

    In multivariate stratified sampling where more than one characteristic are to be estimated, an allocation which is optimum for one characteristic may not be optimum for other characteristics also. In such situations a compromise criterion is needed to work out a usable allocation which is optimum for all characteristics in some ...

  16. Bounds in the location-allocation problem

    DEFF Research Database (Denmark)

    Juel, Henrik

    1981-01-01

    Develops a family of stronger lower bounds on the objective function value of the location-allocation problem. Solution methods proposed to solve problems in location-allocation; Efforts to develop a more efficient bound solution procedure; Determination of the locations of the sources....

  17. A Time Allocation Study of University Faculty

    Science.gov (United States)

    Link, Albert N.; Swann, Christopher A.; Bozeman, Barry

    2008-01-01

    Many previous time allocation studies treat work as a single activity and examine trade-offs between work and other activities. This paper investigates the at-work allocation of time among teaching, research, grant writing and service by science and engineering faculty at top US research universities. We focus on the relationship between tenure…

  18. Obtaining a Proportional Allocation by Deleting Items

    NARCIS (Netherlands)

    Dorn, B.; de Haan, R.; Schlotter, I.; Röthe, J.

    2017-01-01

    We consider the following control problem on fair allocation of indivisible goods. Given a set I of items and a set of agents, each having strict linear preference over the items, we ask for a minimum subset of the items whose deletion guarantees the existence of a proportional allocation in the

  19. Directed networks, allocation properties and hierarchy formation

    NARCIS (Netherlands)

    Slikker, M.; Gilles, R.P.; Norde, H.W.; Tijs, S.H.

    2005-01-01

    We investigate properties for allocation rules on directed communication networks and the formation of such networks under these payoff properties. We study allocation rules satisfying two appealing properties, Component Efficiency (CE) and the Hierarchical Payoff Property (HPP). We show that such

  20. Nash social welfare in multiagent resource allocation

    NARCIS (Netherlands)

    Ramezani, S.; Endriss, U.; David, E.; Gerding, E.; Sarne, D.; Shehory, O.

    2010-01-01

    We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and fairness

  1. Risk and reliability allocation to risk control

    International Nuclear Information System (INIS)

    Vojnovic, D.; Kozuh, M.

    1992-01-01

    The risk allocation procedure is used as an analytical model to support the optimal decision making for reliability/availability improvement planning. Both levels of decision criteria, the plant risk measures and plant performance indices, are used in risk allocation procedure. Decision support system uses the multi objective decision making concept. (author) [sl

  2. Bidding for surplus in network allocation problems

    NARCIS (Netherlands)

    Slikker, M.

    2007-01-01

    In this paper we study non-cooperative foundations of network allocation rules. We focus on three allocation rules: the Myerson value, the position value and the component-wise egalitarian solution. For any of these three rules we provide a characterization based on component efficiency and some

  3. Cost Allocation and Convex Data Envelopment

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tind, Jørgen

    such as Data Envelopment Analysis (DEA). The convexity constraint of the BCC model introduces a non-zero slack in the objective function of the multiplier problem and we show that the cost allocation rules discussed in this paper can be used as candidates to allocate this slack value on to the input (or output...

  4. Carbon cost of plant nitrogen acquisition: global carbon cycle impact from an improved plant nitrogen cycle in the Community Land Model.

    Science.gov (United States)

    Shi, Mingjie; Fisher, Joshua B; Brzostek, Edward R; Phillips, Richard P

    2016-03-01

    Plants typically expend a significant portion of their available carbon (C) on nutrient acquisition - C that could otherwise support growth. However, given that most global terrestrial biosphere models (TBMs) do not include the C cost of nutrient acquisition, these models fail to represent current and future constraints to the land C sink. Here, we integrated a plant productivity-optimized nutrient acquisition model - the Fixation and Uptake of Nitrogen Model - into one of the most widely used TBMs, the Community Land Model. Global plant nitrogen (N) uptake is dynamically simulated in the coupled model based on the C costs of N acquisition from mycorrhizal roots, nonmycorrhizal roots, N-fixing microbes, and retranslocation (from senescing leaves). We find that at the global scale, plants spend 2.4 Pg C yr(-1) to acquire 1.0 Pg N yr(-1) , and that the C cost of N acquisition leads to a downregulation of global net primary production (NPP) by 13%. Mycorrhizal uptake represented the dominant pathway by which N is acquired, accounting for ~66% of the N uptake by plants. Notably, roots associating with arbuscular mycorrhizal (AM) fungi - generally considered for their role in phosphorus (P) acquisition - are estimated to be the primary source of global plant N uptake owing to the dominance of AM-associated plants in mid- and low-latitude biomes. Overall, our coupled model improves the representations of NPP downregulation globally and generates spatially explicit patterns of belowground C allocation, soil N uptake, and N retranslocation at the global scale. Such model improvements are critical for predicting how plant responses to altered N availability (owing to N deposition, rising atmospheric CO2 , and warming temperatures) may impact the land C sink. © 2015 John Wiley & Sons Ltd.

  5. Optimal allocation of resources in systems

    International Nuclear Information System (INIS)

    Derman, C.; Lieberman, G.J.; Ross, S.M.

    1975-01-01

    In the design of a new system, or the maintenance of an old system, allocation of resources is of prime consideration. In allocating resources it is often beneficial to develop a solution that yields an optimal value of the system measure of desirability. In the context of the problems considered in this paper the resources to be allocated are components already produced (assembly problems) and money (allocation in the construction or repair of systems). The measure of desirability for system assembly will usually be maximizing the expected number of systems that perform satisfactorily and the measure in the allocation context will be maximizing the system reliability. Results are presented for these two types of general problems in both a sequential (when appropriate) and non-sequential context

  6. The decadal state of the terrestrial carbon cycle

    NARCIS (Netherlands)

    Velde, van der I.R.; Bloom, J.; Exbrayat, J.; Feng, L.; Williams, M.

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  7. Waste package performance allocation system study report

    International Nuclear Information System (INIS)

    Memory, R.D.

    1994-01-01

    The Waste Package Performance Allocation system study was performed in order to provide a technical basis for the selection of the waste package period of substantially complete containment and its resultant contribution to the overall total system performance. This study began with a reference case based on the current Mined Geologic Disposal System (MGDS) baseline design and added a number of alternative designs. The waste package designs were selected from the designs being considered in detail during Advanced Conceptual Design (ACD). The waste packages considered were multi-barrier packages with a 0.95 cm Alloy 825 inner barrier and a 10, 20, or 45 cm thick carbon steel outer barrier. The waste package capacities varied from 6 to 12 to 21 Pressurized Water Reactor (PWR) fuel assemblies. The vertical borehole and in-drift emplacement modes were also considered, as were thermal loadings of 25, 57, and 114 kW/acre. The repository cost analysis indicated that the 21 PWR in-drift emplacement mode option with the 10 cm and 20 cm outer barrier thicknesses are the least expensive and that the 12 PWR in-drift case has approximately the same cost as the 6 PWR vertical borehole. It was also found that the cost increase from the 10 cm outer barrier waste package to the 20 cm waste package was less per centimeter than the increase from the 20 cm outer barrier waste package to the 45 cm outer barrier waste package. However, the repository cost was nearly linear with the outer barrier thickness for the 21 PWR in-drift case. Finally, corrosion rate estimates are provided and the relationship of repository cost versus waste package lifetime is discussed as is cumulative radionuclide release from the waste package and to the accessible environment for time periods of 10,000 years and 100,000 years

  8. Aboveground and belowground legacies of native Sami land use on boreal forest in northern Sweden 100 years after abandonment.

    Science.gov (United States)

    Freschet, Grégoire T; Ostlund, Lars; Kichenin, Emilie; Wardle, David A

    2014-04-01

    Human activities that involve land-use change often cause major transformations to community and ecosystem properties both aboveground and belowground, and when land use is abandoned, these modifications can persist for extended periods. However, the mechanisms responsible for rapid recovery vs. long-term maintenance of ecosystem changes following abandonment remain poorly understood. Here, we examined the long-term ecological effects of two remote former settlements, regularly visited for -300 years by reindeer-herding Sami and abandoned -100 years ago, within an old-growth boreal forest that is considered one of the most pristine regions in northern Scandinavia. These human legacies were assessed through measurements of abiotic and biotic soil properties and vegetation characteristics at the settlement sites and at varying distances from them. Low-intensity land use by Sami is characterized by the transfer of organic matter towards the settlements by humans and reindeer herds, compaction of soil through trampling, disappearance of understory vegetation, and selective cutting of pine trees for fuel and construction. As a consequence, we found a shift towards early successional plant species and a threefold increase in soil microbial activity and nutrient availability close to the settlements relative to away from them. These changes in soil fertility and vegetation contributed to 83% greater total vegetation productivity, 35% greater plant biomass, and 23% and 16% greater concentrations of foliar N and P nearer the settlements, leading to a greater quantity and quality of litter inputs. Because decomposer activity was also 40% greater towards the settlements, soil organic matter cycling and nutrient availability were further increased, leading to likely positive feedbacks between the aboveground and belowground components resulting from historic land use. Although not all of the activities typical of Sami have left visible residual traces on the ecosystem after

  9. Application of Computer-Aided Tomography (CT) Technology to Visually Compare Belowground Components of Salt Marshes in Jamaica Bay and Long Island, New York

    Science.gov (United States)

    Using CT imaging, we found that rapidly deteriorating marshes in Jamaica Bay had significantly less belowground mass and abundance of coarse roots and rhizomes at depth (< 10 cm) compared to more stable areas in the Jamaica Bay Estuary. In addition, the rhizome diameters and pea...

  10. The relative importance of above- versus belowground competition for tree growth and survival during early succession of a tropical moist forest

    NARCIS (Netherlands)

    Breugel, van M.; Breugel, van P.; Jansen, P.A.; Martinez-Ramos, M.; Bongers, F.

    2012-01-01

    Competition between neighboring plants plays a major role in the population dynamics of tree species in the early phases of humid tropical forest succession. We evaluated the relative importance of above- versus below-ground competition during the first years of old-field succession on soil with low

  11. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  12. Carbon allocation to young loblolly pine roots and stems

    Science.gov (United States)

    Paul P. Kormanik; Shi-Jean S. Sung; Clanton C. Black; Stanley J. Zarnoch

    1995-01-01

    This study of root biomass with loblolly pine was designed with the following objectives: (1) to measure the root biomass for a range of individual trees between the ages of 3 and 10 years on different artificial and natural forest sites and (2) to relate the root biomass to aboveground biomass components.

  13. Urban tree effects on soil organic carbon.

    Directory of Open Access Journals (Sweden)

    Jill L Edmondson

    Full Text Available Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ∼75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C∶N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

  14. Economics and the refinery's CO2 emissions allocation problem

    International Nuclear Information System (INIS)

    Pierru, A.

    2007-01-01

    The establishment of a market for CO 2 emission rights in Europe leads oil-refining companies to add a cost associated with carbon emissions to the objective function of linear programming models used to manage refineries. These models may be used to compute the marginal contribution of each finished product to the CO 2 emissions of the refinery. Babusiaux (Oil. Gas Sci. Technol., 58, 2003, 685-692) has shown that, under some conditions, this marginal contribution is a relevant means of allocating the carbon emissions of the refinery. Thus, it can be used in a well-to-wheel Life Cycle Assessment. In fact, this result holds if the demand equations are the only binding constraints with a non-zero right-hand side coefficient. This is not the case for short-run models with fixed capacity. Then, allocating CO 2 emissions on a marginal basis tends to over-value (or undervalue) the total volume of emissions. In order to extend the existing methodology, we discuss two distinct solutions to this problem, inspired by economic theory: adapting either the Aumann-Shapley cost sharing method (Values of non-atomic games, 1974, Princeton University Press) or the Ramsey pricing formula (Econ. J., 37, 1927, 47-61; J. Econ. Theory, 3, 1971, 219-240). We compare these two solutions, with a strong argument in favour of Ramsey prices, based on the determination of the optimal environmental tax rate to which imported finished products should be subject. (author)

  15. Identifying Memory Allocation Patterns in HEP Software

    Science.gov (United States)

    Kama, S.; Rauschmayr, N.

    2017-10-01

    HEP applications perform an excessive amount of allocations/deallocations within short time intervals which results in memory churn, poor locality and performance degradation. These issues are already known for a decade, but due to the complexity of software frameworks and billions of allocations for a single job, up until recently no efficient mechanism has been available to correlate these issues with source code lines. However, with the advent of the Big Data era, many tools and platforms are now available to do large scale memory profiling. This paper presents, a prototype program developed to track and identify each single (de-)allocation. The CERN IT Hadoop cluster is used to compute memory key metrics, like locality, variation, lifetime and density of allocations. The prototype further provides a web based visualization back-end that allows the user to explore the results generated on the Hadoop cluster. Plotting these metrics for every single allocation over time gives a new insight into application’s memory handling. For instance, it shows which algorithms cause which kind of memory allocation patterns, which function flow causes how many short-lived objects, what are the most commonly allocated sizes etc. The paper will give an insight into the prototype and will show profiling examples for the LHC reconstruction, digitization and simulation jobs.

  16. Belowground carabid beetle diversity in the western Palaearctic – effects of history and climate on range-restricted taxa (Coleoptera, Carabidae

    Directory of Open Access Journals (Sweden)

    Andreas Schuldt

    2011-05-01

    Full Text Available Broad-scale patterns of subterranean diversity are a fascinating but neglected part of biodiversity research. Carabid beetles adapted to belowground habitats form a particularly species-rich part of the subterranean fauna. We studied large-scale diversity patterns of these belowground carabids across the western Palaearctic and evaluated potential impacts of historical and contemporary environmental conditions on the distribution of these taxa, using available species richness and environmental data at country level. Regression modelling and variation partitioning showed a strong relationship between species richness and range in elevation. Potential effects of climatic variables, mainly those related to ambient energy input, were much weaker. We discuss the implications of this combination of effects, which suggests, concordant with the absence of subterranean carabids in northern and highest richness in southern Europe, a strong prevailing influence of historical processes on current richness distributions of these taxa. Previous studies did not provide clear indications for such an influence. In contrast to more mobile and widespread carabid beetles, dispersal limitation due to high adaptation of belowground carabids to subterranean habitats has probably hindered their re-colonization of former permafrost and glaciated regions. Hotspots of highest belowground diversity are located in regions with an assumed long-term stability of environmental conditions, correlating with patterns of other dispersal-limited taxa such as many endemic plants. Our study provides important new information in the discussion of potential determinants of the distinct geographic patterns of belowground diversity. Moreover, it contributes to a better understanding of range size related differences previously found in the distribution of diversity and environmental dependencies of widespread and range-restricted species within the highly diverse carabid beetles.

  17. Welcome to the neighbourhood: interspecific genotype by genotype interactions in Solidago influence above- and belowground biomass and associated communities.

    Science.gov (United States)

    Genung, Mark A; Bailey, Joseph K; Schweitzer, Jennifer A

    2012-01-01

    Intra- and interspecific plant-plant interactions are fundamental to patterns of community assembly and to the mixture effects observed in biodiversity studies. Although much research has been conducted at the species level, very little is understood about how genetic variation within and among interacting species may drive these processes. Using clones of both Solidago altissima and Solidago gigantea, we found that genotypic variation in a plant's neighbours affected both above- and belowground plant traits, and that genotype by genotype interactions between neighbouring plants impacted associated pollinator communities. The traits for which focal plant genotypic variation explained the most variation varied by plant species, whereas neighbour genotypic variation explained the most variation in coarse root biomass. Our results provide new insight into genotypic and species diversity effects in plant-neighbour interactions, the extended consequences of diversity effects, and the potential for evolution in response to competitive or to facilitative plant-neighbour interactions. © 2011 Blackwell Publishing Ltd/CNRS.

  18. Carbon stocks in tree biomass and soils of German forests

    Directory of Open Access Journals (Sweden)

    Wellbrock Nicole

    2017-06-01

    Full Text Available Close to one third of Germany is forested. Forests are able to store significant quantities of carbon (C in the biomass and in the soil. Coordinated by the Thünen Institute, the German National Forest Inventory (NFI and the National Forest Soil Inventory (NFSI have generated data to estimate the carbon storage capacity of forests. The second NFI started in 2002 and had been repeated in 2012. The reporting time for the NFSI was 1990 to 2006. Living forest biomass, deadwood, litter and soils up to a depth of 90 cm have stored 2500 t of carbon within the reporting time. Over all 224 t C ha-1 in aboveground and belowground biomass, deadwood and soil are stored in forests. Specifically, 46% stored in above-ground and below-ground biomass, 1% in dead wood and 53% in the organic layer together with soil up to 90 cm. Carbon stocks in mineral soils up to 30 cm mineral soil increase about 0.4 t C ha-1 yr-1 stocks between the inventories while the carbon pool in the organic layers declined slightly. In the living biomass carbon stocks increased about 1.0 t C ha-1 yr-1. In Germany, approximately 58 mill. tonnes of CO2 were sequestered in 2012 (NIR 2017.

  19. Belowground heathland responses after 2 years of combined warming, elevated CO2 and summer drought

    DEFF Research Database (Denmark)

    Andresen, Louise C.; Michelsen, Anders; Ambus, Per

    2010-01-01

    significantly to the treatments. In the combined temperature and CO2 treatment the dissolved organic nitrogen concentration decreased and the ammonium concentration increased, but this release of nutrients was not mirrored by plant parameters. Microbial biomass carbon and microbial enrichment with 13C and 15N...

  20. Climate change induced range-expanding plants : aboveground and belowground interactions

    NARCIS (Netherlands)

    Morriën, W.E.

    2011-01-01

    Burning of fossil fuels has raised the level of atmospheric carbon dioxide, which contributes to global climate warming. As a result the mean earth surface temperature has increased faster in the past decades than in the previous thousands of years before. This rapid climate warming together

  1. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

    International Nuclear Information System (INIS)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A.; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. - Highlights: • Meta-analysis was used to address the effects of N addition on C cycle. • N addition caused an large decease in belowground plant C pool. • N-rich and N-limited ecosystems had different responses to N addition. - N addition caused a large decrease in below-ground plant C pool.

  2. Worst-case analysis of heap allocations

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang; Huber, Benedikt; Schoeberl, Martin

    2010-01-01

    the worst-case heap allocations of tasks. The analysis builds upon techniques that are well established for worst-case execution time analysis. The difference is that the cost function is not the execution time of instructions in clock cycles, but the allocation in bytes. In contrast to worst-case execution...... time analysis, worst-case heap allocation analysis is not processor dependent. However, the cost function depends on the object layout of the runtime system. The analysis is evaluated with several real-time benchmarks to establish the usefulness of the analysis, and to compare the memory consumption...

  3. Depression of belowground respiration is more pronounced than enhancement of photosynthesis during the first year after nitrogen fertilization of a mature Pacific Northwest Douglas-fir forest

    Science.gov (United States)

    Chen, B.; Black, T. A.; Jassal, R.; Nesic, Z.; Bruemmer, C.

    2008-05-01

    Nitrogen (N) additions to forest have shown variable effects on both respiration and photosynthesis. With increasing rates of anthropogenic N deposition, there is a strong need to understand the ecosystem response to N inputs. We investigated how N fertilization affects the ecosystem carbon (C) balance of a 57-year-old coast Douglas-fir stand in British Columbia, Canada, based on eddy-covariance (EC) and soil-chamber (fertilized and control plots) measurements and process-based modeling. The stand was fertilized by helicopter with urea at 200 kg N ha-1 in January 2007. A land surface model (Ecosystem Atmosphere Simulation Scheme, EASS) was combined with an ecosystem model (Boreal Ecosystem Productivity Simulator, BEPS) and a coupled C and N subroutine was incorporated into the integrated EASS-BEPS model in this study. This half-hourly time step model was run continuously for the period from 2001 to 2007 in two scenarios: with and without fertilization. Modeled C fluxes without fertilization [net ecosystem productivity (NEP), gross primary productivity (GPP), ecosystem respiration (Re) and belowground respiration (Rs)] agreed well with EC and soil chamber measurements over diurnal, seasonal and annual time scales for 2001 to 2006; while simulated NEP, GPP, Re and Rs with fertilization reasonably followed EC and chamber measurements in 2007 (545 vs. 520, 2163 vs. 2155, 1618 vs. 1635, and 920 vs. 906 g C m-2 yr-1, respectively). Comparison of EC-determined C fluxes in 2007 with model simulations without fertilization suggests that annual Re decreased by 6.7% (1635 vs. 1752 g C m-2), gross primary productivity (GPP) increased by 6.8% (2155 vs. 2017 g C m-2), and annual NEP increased by 96.2% (520 vs. 265 g C m-2) due to fertilization. The modeled reduction in Rs (9.6%, comparing modeled values without and with fertilization: 1008 vs. 920 g C m-2 yr-1) is consistent with that measured using the soil chambers (~11.5%, comparing CO2 effluxes from control and fertilized

  4. ALLOCATION OF FINANCIAL RESOURCE TO ENHANCE ...

    African Journals Online (AJOL)

    GRACE

    This study examines the allocation of financial resource to the education industry and ..... This should check all books of account at least once a month to reconcile ... All cash advance request must be supported with relevant documents vii.

  5. Fund allocation using capacitated vehicle routing problem

    Science.gov (United States)

    Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Darus, Maslina

    2014-09-01

    In investment fund allocation, it is unwise for an investor to distribute his fund into several assets simultaneously due to economic reasons. One solution is to allocate the fund into a particular asset at a time in a sequence that will either maximize returns or minimize risks depending on the investor's objective. The vehicle routing problem (VRP) provides an avenue to this issue. VRP answers the question on how to efficiently use the available fleet of vehicles to meet a given service demand, subjected to a set of operational requirements. This paper proposes an idea of using capacitated vehicle routing problem (CVRP) to optimize investment fund allocation by employing data of selected stocks in the FTSE Bursa Malaysia. Results suggest that CRVP can be applied to solve the issue of investment fund allocation and increase the investor's profit.

  6. U.S. Army Recruiter Allocation Model

    National Research Council Canada - National Science Library

    Brence, John

    2004-01-01

    .... Our methodology will build on both the new and old schools of recruiting by conducting stakeholder interviews that will lead us to a model that is an efficient starting point for the Recruiter Mission Allocation (RMA...

  7. Optimal Resource Allocation in Library Systems

    Science.gov (United States)

    Rouse, William B.

    1975-01-01

    Queueing theory is used to model processes as either waiting or balking processes. The optimal allocation of resources to these processes is defined as that which maximizes the expected value of the decision-maker's utility function. (Author)

  8. Resource allocation based on cost efficiency

    DEFF Research Database (Denmark)

    Dehnokhalaji, Akram; Ghiyasi, Mojtaba; Korhonen, Pekka

    2017-01-01

    -objective linear programming problem using two different strategies. First, we propose an RA model which keeps the cost efficiencies of units unchanged. This is done assuming fixed technical and allocative efficiencies. The approach is based on the assumption that the decision maker (DM) may not have big changes......In this paper, we consider a resource allocation (RA) problem and develop an approach based on cost (overall) efficiency. The aim is to allocate some inputs among decision making units (DMUs) in such way that their cost efficiencies improve or stay unchanged after RA. We formulate a multi...... in the structure of DMUs within a short term. The second strategy does not impose any restrictions on technical and allocative efficiencies. It guarantees that none of the cost efficiencies of DMUs get worse after RA, and the improvement for units is possible if it is feasible and beneficial. Two numerical...

  9. regional grain allocation and transportation in China

    African Journals Online (AJOL)

    use

    2011-12-14

    Dec 14, 2011 ... China was partitioned into eight regions, and the virtual water flow due to regional grain allocation and ... strategy can be choices which can realize Chinese food security and ..... Globalization of water: Sharing the planet's ...

  10. Telecommunications Circuit Allocation Programs - Kansas City Area

    National Research Council Canada - National Science Library

    Thomas, William

    1994-01-01

    The overall objective of the audit was to determine whether DoD circuit allocation programs identified and used the most effective configurations for leased long-haul, special-purpose telecommunications circuits...

  11. Data for developing allometric models and evaluating carbon stocks of the Zambezi Teak Forests in Zambia.

    Science.gov (United States)

    Ngoma, Justine; Moors, Eddy; Kruijt, Bart; Speer, James H; Vinya, Royd; Chidumayo, Emmanuel N; Leemans, Rik

    2018-04-01

    This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection on applying this data.

  12. Macroeconomic influences on optimal asset allocation

    OpenAIRE

    Flavin, Thomas; Wickens, M.R.

    2003-01-01

    We develop a tactical asset allocation strategy that incorporates the effects of macroeconomic variables. The joint distribution of financial asset returns and the macroeconomic variables is modelled using a VAR with a multivariate GARCH (M-GARCH) error structure. As a result, the portfolio frontier is time varying and subject to contagion from the macroeconomic variable. Optimal asset allocation requires that this be taken into account. We illustrate how to do this using three ri...

  13. Human Capital and Risky Asset Allocation

    OpenAIRE

    Lu, Wenjie; Yu, Qun

    2011-01-01

    Much research has been done to examine the relation between investors' human capital and their financial asset allocation. While some showed that the value of human capital should be taken into consideration to make financial asset allocation decisions on the composition of investing portfolios, most argued not. In this paper, we selected the monthly return of 9 industrial ETFs from June of 2007 to July 2011, used the present value of total future income as estimate of human capital, and reli...

  14. Cost Allocation and Overpricing of Spare Parts.

    Science.gov (United States)

    1986-09-01

    traditional cost allocation process as reported in accounting literature. Horngren reported there are essen- tially three facets of cost allocation as...is for more than one unit of a product. Horngren reports cost accounting systems commonly have two major cost objectives: departments and products (8...Standards Board: Standards, Rules, and Regulations. Washington: Government Printing Office, 1985. 8. Horngren , Charles T. Cost Accounting : A Managerial

  15. Cost allocation. Combined heat and power production

    International Nuclear Information System (INIS)

    Sidzikauskas, V.

    2002-01-01

    The benefits of Combined Heat and Power (CHP) generation are discussed. The include improvement in energy intensity of 1% by 2010, 85-90% efficiency versus 40-50% of condensation power and others. Share of CHP electricity production in ERRA countries is presented.Solutions for a development CHP cost allocation are considered. Conclusion are presented for CHP production cost allocation. (R.P.)

  16. Allocation of authority in European health policy.

    Science.gov (United States)

    Adolph, Christopher; Greer, Scott L; Massard da Fonseca, Elize

    2012-11-01

    Although many study the effects of different allocations of health policy authority, few ask why countries assign responsibility over different policies as they do. We test two broad theories: fiscal federalism, which predicts rational governments will concentrate information-intensive operations at lower levels, and redistributive and regulatory functions at higher levels; and "politicized federalism", which suggests a combination of systematic and historically idiosyncratic political variables interfere with efficient allocation of authority. Drawing on the WHO Health in Transition country profiles, we present new data on the allocation of responsibility for key health care policy tasks (implementation, provision, finance, regulation, and framework legislation) and policy areas (primary, secondary and tertiary care, public health and pharmaceuticals) in the 27 EU member states and Switzerland. We use a Bayesian multinomial mixed logit model to analyze how different countries arrive at different allocations of authority over each task and area of health policy, and find the allocation of powers broadly follows fiscal federalism. Responsibility for pharmaceuticals, framework legislation, and most finance lodges at the highest levels of government, acute and primary care in the regions, and provision at the local and regional levels. Where allocation does not follow fiscal federalism, it appears to reflect ethnic divisions, the population of states and regions, the presence of mountainous terrain, and the timing of region creation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Influences of rising atmospheric carbon dioxide and ozone concentrations on soil respiration, soil microbial biomass, nutrient availability and soil C dynamics in a soybean-wheat no-till system

    Science.gov (United States)

    Effects of the elevated carbon dioxide and ozone on agroecosystems include effects on root growth, soil microbiology and soil C dynamics although the combined effects of these gases on belowground processes have been little studied. The objective of this experiment was to determine the separate and...

  18. Leveraging Carbon Cycling in Coastal Wetlands for Habitat Conservation: Blue Carbon Policy Opportunities (Invited)

    Science.gov (United States)

    Sutton-Grier, A.

    2013-12-01

    Recent scientific studies suggest that the carbon sequestered and stored in coastal wetlands (specifically mangroves, salt marshes, and seagrass meadows) is an important, previously not well-recognized service provided by these ecosystems. Coastal wetlands have unique characteristics that make them incredibly efficient, natural carbon sinks with most carbon stored belowground in soils. Based on this new scientific evidence, there is growing interest in leveraging the carbon services of these habitats (termed 'blue carbon') to develop new policy opportunities to protect and restore coastal wetlands around the globe. The overall goal is to take full advantage of the carbon services of these habitats in order to ensure and maintain the many benefits provided to society by these habitats - including natural climate, food security, and storm protection benefits - and to enhance the resiliency of coastal communities and economies around the world. This presentation will give an update on some of the policy opportunities including: (1) examining how the implementation of U.S. federal policies can be expanded to include carbon services of ecosystems in order to improve management and decision making; (2) developing an international blue carbon community of science and practice to provide best practice guidance for protection and restoration of blue carbon habitats; and (3) developing innovative financing mechanisms for coastal conservation including carbon market credits for wetlands. Finally, the presentation will conclude by highlighting some of the most pressing blue carbon scientific gaps that need to be filled in order to support these developing policies.

  19. Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

    Directory of Open Access Journals (Sweden)

    M. Ueyama

    2010-03-01

    Full Text Available Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales.

    The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE, gross primary productivity (GPP, ecosystem respiration (RE, and evapotranspiration (ET. Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values.

    The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation

  20. Online Job Allocation with Hard Allocation Ratio Requirement (Author’s Manuscript)

    Science.gov (United States)

    2016-04-14

    server divided by its capacity. Specifically , let nj be the number of jobs that have already been allocated to server j. When job i arrives, it is...decisions solely based on current system state is needed. The problem of online job allocation has attracted much attention . Most current studies study...closed-form expressions for their performance. Specifically , we prove that, in order to allocate at least 1− 1θ of jobs , the two policies only need to

  1. Peatland carbon stocks and accumulation rates in the Ecuadorian páramo

    Science.gov (United States)

    John A. Hribljan; Esteban Suarez; Katherine A. Heckman; Erik Lilleskov; Rodney A. Chimner

    2016-01-01

    The páramo is a high altitude tropical Andean ecosystem that contains peatlands with thick horizons of carbon (C) dense soils. Soil C data are sparse for most of the pa´ramo, especially in peatlands, which limits our ability to provide accurate regional and country wide estimates of C storage. Therefore, the objective of our research was to quantify belowground C...

  2. Norway spruce fine root dynamics and carbon input into soil in relation to environmental factors

    OpenAIRE

    Leppälammi-Kujansuu, Jaana

    2014-01-01

    Knowledge of the quantity of belowground litter carbon (C) input is scarce but highly valued in C budget calculations. Specifically, the turnover rate of fine roots is considered to be one of the most important parameters in the estimation of changes in soil C stock. In this thesis Norway spruce (Picea abies L. (Karst.)) fine root lifespan and litter production and their responses to nutrient availability and temperature were examined. Aboveground foliage and understory litter C inputs were a...

  3. Limits on carbon sequestration in arid blue carbon ecosystems.

    Science.gov (United States)

    Schile, Lisa M; Kauffman, J Boone; Crooks, Stephen; Fourqurean, James W; Glavan, Jane; Megonigal, J Patrick

    2017-04-01

    Coastal ecosystems produce and sequester significant amounts of carbon ("blue carbon"), which has been well documented in humid and semi-humid regions of temperate and tropical climates but less so in arid regions where mangroves, marshes, and seagrasses exist near the limit of their tolerance for extreme temperature and salinity. To better understand these unique systems, we measured whole-ecosystem carbon stocks in 58 sites across the United Arab Emirates (UAE) in natural and planted mangroves, salt marshes, seagrass beds, microbial mats, and coastal sabkha (inter- and supratidal unvegetated salt flats). Natural mangroves held significantly more carbon in above- and belowground biomass than other vegetated ecosystems. Planted mangrove carbon stocks increased with age, but there were large differences for sites of similar age. Soil carbon varied widely across sites (2-367 Mg C/ha), with ecosystem averages that ranged from 49 to 156 Mg C/ha. For the first time, microbial mats were documented to contain soil carbon pools comparable to vascular plant-dominated ecosystems, and could arguably be recognized as a unique blue carbon ecosystem. Total ecosystem carbon stocks ranged widely from 2 to 515 Mg C/ha (seagrass bed and mangrove, respectively). Seagrass beds had the lowest carbon stock per unit area, but the largest stock per total area due to their large spatial coverage. Compared to similar ecosystems globally, mangroves and marshes in the UAE have lower plant and soil carbon stocks; however, the difference in soil stocks is far larger than with plant stocks. This incongruent difference between stocks is likely due to poor carbon preservation under conditions of weakly reduced soils (200-350 mV), coarse-grained sediments, and active shoreline migration. This work represents the first attempt to produce a country-wide coastal ecosystem carbon accounting using a uniform sampling protocol, and was motivated by specific policy goals identified by the Abu Dhabi Global

  4. SEASONAL CHANGES IN ROOT AND SOIL RESPIRATION OF OZONE-EXPOSED PONDEROSA PINE (PINUS PONDEROSA) GROWN IN DIFFERENT SUBSTRATES

    Science.gov (United States)

    Exposure to(ozone 0-3)has been shown to decrease the allocation of carbon to tree roots. Decreased allocation of carbon to roots might disrupt root metabolism and rhizosphere organisms. The effects of soil type and shoot 0, exposure on below-ground respiration and soil microbial ...

  5. Analysis of standard and innovative methods for allocating upstream and refinery GHG emissions to oil products

    International Nuclear Information System (INIS)

    Moretti, Christian; Moro, Alberto; Edwards, Robert; Rocco, Matteo Vincenzo; Colombo, Emanuela

    2017-01-01

    Highlights: •Traditional and innovative methods for allocating emissions at refinery level are reviewed. •Added value has been introduced as a novel allocation method. •Hydrogen-based consistency test has been introduced to validate the allocation methods. •Consistent allocation methods assign negative refinery emissions to heavy products. -- Abstract: Alternative fuel policies need accurate and transparent methods to find the embedded carbon intensity of individual refinery products. This study investigates different ways of allocating greenhouse gases emissions deriving from refining and upstream crude oil supply. Allocation methods based on mass, energy content, economic value and, innovatively, added-value, are compared with the marginal refining emissions calculated by CONCAWE’s linear-programming model to the average EU refinery, which has been adopted as reference in EU legislation. Beside the most important transportation fuels (gasoline, diesel, kerosene/jet fuel and heavy fuel oil), the analysis extends to petroleum coke and refinery hydrogen. Moreover, novel criteria, based on the implications due to hydrogen usage by each fuel pathway, have been introduced to test the consistency of the analyzed approaches. It is found that only two economic-based allocation methods are consistent with the introduced criteria. These two methods also give negative refinery emissions for heavy products, which is coherent with the marginal emissions calculated through the CONCAWE refinery model. The recommended allocation methods are transparent and use only publicly available statistical data, so they may be useful not only for future EU legislation, but also in jurisdictions where a representative refinery model is not available.

  6. Decomposition of belowground litter and metal dynamics in salt marshes (Tagus Estuary, Portugal)

    International Nuclear Information System (INIS)

    Pereira, Patricia; Cacador, Isabel; Vale, Carlos; Caetano, Miguel; Costa, Ana Luisa

    2007-01-01

    The concentrations of C, Fe, Mn, Zn, Cu, Pb and Cd were determined monthly in decomposing roots of Halimione portulacoides, using litterbag experiments, in two salt marshes of the Tagus estuary with different levels of contamination. Although carbon concentrations varied within a narrow interval during the experiment, litter decomposed rapidly in the first month (weight loss between 0.051 and 0.065 g d -1 ). The time variation of metals was examined in terms of Me/C ratios and metal stocks. Ratios of Fe/C and Mn/C and their metal stocks increased in spring, presumably due to the precipitation of oxides in the surface of decomposing roots. Subsequent decrease of Fe/C and Mn/C ratios suggests the use of Fe and Mn oxides, as electron acceptors, in the organic matter oxidation. Zinc, Cu, Pb and Cd ratios to C were, in general, higher than at initial conditions implying that metal that leached out was slower than carbon. However, metal stocks decreased during the experiment indicating that incorporation or sorption of metals in Fe and Mn oxides did not counterbalance the amount of Zn, Pb and Cd released from decomposing litter. An exception was observed for Cu, since stock in the less contaminated marsh (Pancas) increased during the decomposition, indicating that litter was efficient on Cu binding under more oxidising conditions. These results emphasize the importance of litter decomposition and sediment characteristics on metal cycling in salt marshes

  7. Methodology for the free allocation of emission allowances in the EU ETS post 2012. Sector report for the chemical industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-11-15

    In 2013, the third trading period of the EU emission trading scheme (EU ETS) will start. With a few exceptions, no free allocation of emission allowances is foreseen in this third trading period for the emissions related to the production of electricity. These emission allowances will be auctioned. For other emissions, transitional free allocation of emission allowances is envisioned. This free allocation will be based on Community wide allocation rules that will, to the extent feasible, be based on ex-ante benchmarks. In 2013, the free allocation is 80% of the quantity determined via these rules, going down to 30% in 2020. An exception is made for activities that are deemed to be exposed to a significant risk of carbon leakage. These activities will receive an allocation of 100% of the quantity determined via the rules. The benchmarks should in principle be calculated for products, i.e. a specific performance per unit productive output, to ensure that they maximize greenhouse gas reductions throughout each production process of the sectors concerned. In this study for the European Commission, a blueprint for a methodology based on benchmarking is developed to determine the allocation rules in the EU ETS from 2013 onwards. In case where benchmarking is not regarded feasible, alternative approaches are suggested. The methodology allows determining the allocation for each EU ETS installation eligible for free allocation of emission allowances. The focus of this study is on preparing a first blueprint of an allocation methodology for free allocation of emission allowances under the EU Emission Trading Scheme for the period 2013-2020 for installations in the refinery industry. The report should be read in conjunction with the report on the project approach and general issues.

  8. Methodology for the free allocation of emission allowances in the EU ETS post 2012. Sector report for the refinery industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-11-15

    In 2013, the third trading period of the EU emission trading scheme (EU ETS) will start. With a few exceptions, no free allocation of emission allowances is foreseen in this third trading period for the emissions related to the production of electricity. These emission allowances will be auctioned. For other emissions, transitional free allocation of emission allowances is envisioned. This free allocation will be based on Community wide allocation rules that will, to the extent feasible, be based on ex-ante benchmarks. In 2013, the free allocation is 80% of the quantity determined via these rules, going down to 30% in 2020. An exception is made for activities that are deemed to be exposed to a significant risk of carbon leakage. These activities will receive an allocation of 100% of the quantity determined via the rules. The benchmarks should in principle be calculated for products, i.e. a specific performance per unit productive output, to ensure that they maximize greenhouse gas reductions throughout each production process of the sectors concerned. In this study for the European Commission, a blueprint for a methodology based on benchmarking is developed to determine the allocation rules in the EU ETS from 2013 onwards. In case where benchmarking is not regarded feasible, alternative approaches are suggested. The methodology allows determining the allocation for each EU ETS installation eligible for free allocation of emission allowances. The focus of this study is on preparing a first blueprint of an allocation methodology for free allocation of emission allowances under the EU Emission Trading Scheme for the period 2013-2020 for installations in the refinery industry. The report should be read in conjunction with the report on the project approach and general issues.

  9. SOME NOTES ON COST ALLOCATION IN MULTICASTING

    Directory of Open Access Journals (Sweden)

    Darko Skorin-Kapov

    2012-12-01

    Full Text Available We analyze the cost allocation strategies with the problef of broadcasting information from some source to a number of communication network users. A multicast routing chooses a minimum cost tree network that spans the source and all the receivers. The cost of such a network is distributed among its receivers who may be individuals or organizations with possibly conflicting interests. Providing network developers, users and owners with practical computable 'fair' cost allocation solution procedures is of great importance for network mamagement. Consequently, this multidisciplinary problem was extensively studied by Operational Researchers, Economists, Mathematicians and Computer Scientists. The fairness of various proposed solutions was even argued in US courts. This presentation overviews some previously published, as well as some recent results, in the development of algorithmic mechanisms to efficiently compute 'attractive' cost allocation solutions for multicast networks. Specifically, we will analyze cooperative game theory based cost allocation models that avoid cross subsidies and/or are distance and population monotonic. We will also present some related open cost allocation problems and the potential contribution that such models might make to this problem in the future.

  10. Cognitive allocation and the control room

    International Nuclear Information System (INIS)

    Paradies, M.W.

    1985-01-01

    One of the weakest links in the design of nuclear power plants is the inattention to the needs and capabilities of the operators. This flaw causes decreased plant reliability and reduced plant safety. To solve this problem the designer must, in the earliest stages of the design process, consider the operator's abilities. After the system requirements have been established, the designer must consider what functions to allocate to each part of the system. The human must be considered as part of this system. The allocation of functions needs to consider not only the mechanical tasks to be performed, but also the control requirements and the overall control philosophy. In order for the designers to consider the control philosophy, they need to know what control decisions should be automated and what decisions should be made by an operator. They also need to know how these decisions will be implemented: by an operator or by automation. ''Cognitive Allocation'' is the allocation of the decision making process between operators and machines. It defines the operator's role in the system. When designing a power plant, a cognitive allocation starts the process of considering the operator's abilities. This is the first step to correcting the weakest link in the current plant design

  11. Methodology for allocating reliability and risk

    International Nuclear Information System (INIS)

    Cho, N.Z.; Papazoglou, I.A.; Bari, R.A.

    1986-05-01

    This report describes a methodology for reliability and risk allocation in nuclear power plants. The work investigates the technical feasibility of allocating reliability and risk, which are expressed in a set of global safety criteria and which may not necessarily be rigid, to various reactor systems, subsystems, components, operations, and structures in a consistent manner. The report also provides general discussions on the problem of reliability and risk allocation. The problem is formulated as a multiattribute decision analysis paradigm. The work mainly addresses the first two steps of a typical decision analysis, i.e., (1) identifying alternatives, and (2) generating information on outcomes of the alternatives, by performing a multiobjective optimization on a PRA model and reliability cost functions. The multiobjective optimization serves as the guiding principle to reliability and risk allocation. The concept of ''noninferiority'' is used in the multiobjective optimization problem. Finding the noninferior solution set is the main theme of the current approach. The final step of decision analysis, i.e., assessment of the decision maker's preferences could then be performed more easily on the noninferior solution set. Some results of the methodology applications to a nontrivial risk model are provided, and several outstanding issues such as generic allocation, preference assessment, and uncertainty are discussed. 29 refs., 44 figs., 39 tabs

  12. Land-use type and intensity differentially filter traits in above- and below-ground arthropod communities.

    Science.gov (United States)

    Birkhofer, Klaus; Gossner, Martin M; Diekötter, Tim; Drees, Claudia; Ferlian, Olga; Maraun, Mark; Scheu, Stefan; Weisser, Wolfgang W; Wolters, Volkmar; Wurst, Susanne; Zaitsev, Andrey S; Smith, Henrik G

    2017-05-01

    Along with the global decline of species richness goes a loss of ecological traits. Associated biotic homogenization of animal communities and narrowing of trait diversity threaten ecosystem functioning and human well-being. High management intensity is regarded as an important ecological filter, eliminating species that lack suitable adaptations. Below-ground arthropods are assumed to be less sensitive to such effects than above-ground arthropods. Here, we compared the impact of management intensity between (grassland vs. forest) and within land-use types (local management intensity) on the trait diversity and composition in below- and above-ground arthropod communities. We used data on 722 arthropod species living above-ground (Auchenorrhyncha and Heteroptera), primarily in soil (Chilopoda and Oribatida) or at the interface (Araneae and Carabidae). Our results show that trait diversity of arthropod communities is not primarily reduced by intense local land use, but is rather affected by differences between land-use types. Communities of Auchenorrhyncha and Chilopoda had significantly lower trait diversity in grassland habitats as compared to forests. Carabidae showed the opposite pattern with higher trait diversity in grasslands. Grasslands had a lower proportion of large Auchenorrhyncha and Carabidae individuals, whereas Chilopoda and Heteroptera individuals were larger in grasslands. Body size decreased with land-use intensity across taxa, but only in grasslands. The proportion of individuals with low mobility declined with land-use intensity in Araneae and Auchenorrhyncha, but increased in Chilopoda and grassland Heteroptera. The proportion of carnivorous individuals increased with land-use intensity in Heteroptera in forests and in Oribatida and Carabidae in grasslands. Our results suggest that gradients in management intensity across land-use types will not generally reduce trait diversity in multiple taxa, but will exert strong trait filtering within

  13. Optimal load allocation of complex ship power plants

    International Nuclear Information System (INIS)

    Baldi, Francesco; Ahlgren, Fredrik; Melino, Francesco; Gabrielii, Cecilia; Andersson, Karin

    2016-01-01

    Highlights: • The optimal operation of the prime movers of hybrid ship power plants is addressed. • Both mechanical, electric and thermal power demand are considered. • The problem is modelled as a mixed integer-nonlinear programming problem. • Up to 3% savings can be achieved with hybrid power plants. • Including the thermal power demand improves the solution by up to 4%. - Abstract: In a world with increased pressure on reducing fuel consumption and carbon dioxide emissions, the cruise industry is growing in size and impact. In this context, further effort is required for improving the energy efficiency of cruise ship energy systems. In this paper, we propose a generic method for modelling the power plant of an isolated system with mechanical, electric and thermal power demands and for the optimal load allocation of the different components that are able to fulfil the demand. The optimisation problem is presented in the form of a mixed integer linear programming (MINLP) problem, where the number of engines and/or boilers running is represented by the integer variables, while their respective load is represented by the non-integer variables. The individual components are modelled using a combination of first-principle models and polynomial regressions, thus making the system nonlinear. The proposed method is applied to the load-allocation problem of a cruise ship sailing in the Baltic Sea, and used to compare the existing power plant with a hybrid propulsion plant. The results show the benefits brought by using the proposing method, which allow estimating the performance of the hybrid system (for which the load allocation is a non-trivial problem) while also including the contribution of the heat demand. This allows showing that, based on a reference round voyage, up to 3% savings could be achieved by installing the proposed system, compared to the existing one, and that a NPV of 11 kUSD could be achieved already 5 years after the installation of the

  14. An Analysis and Allocation System for Library Collections Budgets: The Comprehensive Allocation Process (CAP)

    Science.gov (United States)

    Lyons, Lucy Eleonore; Blosser, John

    2012-01-01

    The "Comprehensive Allocation Process" (CAP) is a reproducible decision-making structure for the allocation of new collections funds, for the reallocation of funds within stagnant budgets, and for budget cuts in the face of reduced funding levels. This system was designed to overcome common shortcomings of current methods. Its philosophical…

  15. Availability and temporal heterogeneity of water supply affect the vertical distribution and mortality of a belowground herbivore and consequently plant growth.

    Science.gov (United States)

    Tsunoda, Tomonori; Kachi, Naoki; Suzuki, Jun-Ichirou

    2014-01-01

    We examined how the volume and temporal heterogeneity of water supply changed the vertical distribution and mortality of a belowground herbivore, and consequently affected plant biomass. Plantago lanceolata (Plantaginaceae) seedlings were grown at one per pot under different combinations of water volume (large or small volume) and heterogeneity (homogeneous water conditions, watered every day; heterogeneous conditions, watered every 4 days) in the presence or absence of a larva of the belowground herbivorous insect, Anomala cuprea (Coleoptera: Scarabaeidae). The larva was confined in different vertical distributions to top feeding zone (top treatment), middle feeding zone (middle treatment), or bottom feeding zone (bottom treatment); alternatively no larva was introduced (control treatment) or larval movement was not confined (free treatment). Three-way interaction between water volume, heterogeneity, and the herbivore significantly affected plant biomass. With a large water volume, plant biomass was lower in free treatment than in control treatment regardless of heterogeneity. Plant biomass in free treatment was as low as in top treatment. With a small water volume and in free treatment, plant biomass was low (similar to that under top treatment) under homogeneous water conditions but high under heterogeneous ones (similar to that under middle or bottom treatment). Therefore, there was little effect of belowground herbivory on plant growth under heterogeneous water conditions. In other watering regimes, herbivores would be distributed in the shallow soil and reduced root biomass. Herbivore mortality was high with homogeneous application of a large volume or heterogeneous application of a small water volume. Under the large water volume, plant biomass was high in pots in which the herbivore had died. Thus, the combinations of water volume and heterogeneity affected plant growth via the change of a belowground herbivore.

  16. Epiphyte-cover on seagrass (Zostera marina L. leaves impedes plant performance and radial O2 loss from the below-ground tissue

    Directory of Open Access Journals (Sweden)

    Kasper Elgetti Brodersen

    2015-08-01

    Full Text Available The O2 budget of seagrasses is a complex interaction between several sources and sinks, which is strongly regulated by light availability and mass transfer over the diffusive boundary layer (DBL surrounding the plant. Epiphyte growth on leaves may thus strongly affect the O2 availability of the seagrass plant and its capability to aerate its rhizosphere as a defence against plant toxins.We used electrochemical and fiber-optic microsensors to quantify the O2 flux, DBL and light microclimate around leaves with and without filamentous algal epiphytes. We also quantified the below-ground radial O2 loss from roots (~1 mm from the root-apex to elucidate how this below-ground oxic microzone was affected by the presence of epiphytes.Epiphyte-cover on seagrass leaves (~21% areal cover resulted in reduced light quality and quantity for photosynthesis, thus leading to reduced plant fitness. A ~4 times thicker diffusive boundary layer around leaves with epiphyte-cover impeded gas (and nutrient exchange with the surrounding water-column and thus the amount of O2 passively diffusing into the leaves in darkness. During light exposure of the leaves, radial oxygen loss from the below-ground tissue was ~2 times higher from plants without epiphyte-cover. In contrast, no O2 was detectable at the surface of the root-cap tissue of plants with epiphyte-cover during darkness, leaving the plants more susceptible to sulphide intrusion.Epiphyte growth on seagrass leaves thus negatively affects the light climate and O2 uptake in darkness, hampering the plants performance and thereby reducing the oxidation capability of its below-ground tissue.

  17. Development of allometric models for above and belowground biomass in swidden cultivation fallows of Northern Laos

    DEFF Research Database (Denmark)

    McNicol, Iain M.; Berry, Nicholas J.; Bruun, Thilde Bech

    2015-01-01

    fields and patches of mature forest. Quantifying tree biomass in these landscapes is limited by the availability of reliable allometric models, hindering accurate carbon stock estimation and thus quantification of GHG emission associated with land use transitions. We therefore developed new allometric...... for each tree type. Thus, we suggest that field efforts should be directed towards checking resprouting status over the estimation of tree height. We also found that models fit using non-linear regression provided equally good fits to the data compared to the traditional approach of log......-transforming the data. Our models were subsequently applied to 12 nearby plots spanning a chronosequence of fallows to examine the impact of re-sprouting allometry on biomass estimation. Root biomass stocks were on average 58% higher after accounting for the allometry of resprouting trees, resulting in an average 9...

  18. 24 CFR 791.404 - Field Office allocation planning.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Field Office allocation planning... Allocation of Budget Authority for Housing Assistance § 791.404 Field Office allocation planning. (a) General objective. The allocation planning process should provide for the equitable distribution of available budget...

  19. 18 CFR 367.28 - Methods of allocation.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Methods of allocation... Instructions § 367.28 Methods of allocation. Indirect costs and compensation for use of capital must be... allocation. Both direct and allocated indirect costs on projects must be assigned among those companies in...

  20. 17 CFR 256.01-11 - Methods of allocation.

    Science.gov (United States)

    2010-04-01

    ... applicable and currently effective methods of allocation filed with the Commission. Both direct and allocated... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Methods of allocation. 256.01... HOLDING COMPANY ACT OF 1935 General Instructions § 256.01-11 Methods of allocation. Indirect costs and...

  1. 40 CFR 60.4142 - Hg allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Hg allowance allocations. 60.4142... Coal-Fired Electric Steam Generating Units Hg Allowance Allocations § 60.4142 Hg allowance allocations. (a)(1) The baseline heat input (in MMBtu) used with respect to Hg allowance allocations under...

  2. Participation behavior and social welfare in repeated task allocations

    NARCIS (Netherlands)

    Ye, Q.C.; Zhang, Y.

    2016-01-01

    Task allocation problems have focused on achieving one-shot optimality. In practice, many task allocation problems are of repeated nature, where the allocation outcome of previous rounds may influence the participation of agents in subsequent rounds, and consequently, the quality of the allocations

  3. Emission projections 2008-2012 versus national allocation plans II

    International Nuclear Information System (INIS)

    Neuhoff, Karsten; Ferrario, Federico; Grubb, Michael; Gabel, Etienne; Keats, Kim

    2006-01-01

    We compare the national allocation plans (NAPs), proposed and submitted by EU Member States as of October 2006, with our estimations for CO 2 emissions by the installations covered by these NAPs. The collective allocations proposed under phase II NAPs exceed the historic trend of emissions extrapolated forward. Using our projections we find, depending on uncertainty in fuel prices, economic growth rates, performance of the non-power sector and CDM/JI availability, a 15% chance of a 'dead market' with emissions below cap even at zero prices. With an expected inflow of committed CDM/JI credits of 100 MtCO 2 /year, allowance supply will exceed demand in 50% of cases without any carbon price, and in 80% of our euros20/tCO 2 scenarios. Banking of allowances towards post-2012 conditions could create additional demand, but this is difficult to anticipate and conditional on policy evolution. The proposed phase II NAPs would result in low prices and only small volumes of CDM/JI would enter the EU ETS. CDM/JI would almost exclusively be public-sector funded, placing the cost of Kyoto compliance entirely upon governments. (Author)

  4. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    2011-01-01

    Efficiently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in finding train routes. Since the problem of routing trains......, and train routing problems, group them by railway network type, and discuss track allocation from a strategic, tactical, and operational level....... on a railway network entails allocating the track capacity of the network (or part thereof) over time in a conflict-free manner, all studies that model railway track allocation in some capacity are considered relevant. We hence survey work on the train timetabling, train dispatching, train platforming...

  5. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    Eciently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in nding train routes. Since the problem of routing trains......, and train routing problems, group them by railway network type, and discuss track allocation from a strategic, tactical, and operational level....... on a railway network entails allocating the track capacity of the network (or part thereof) over time in a con ict-free manner, all studies that model railway track allocation in some capacity are considered relevant. We hence survey work on the train timetabling, train dispatching, train platforming...

  6. Task mapping for non-contiguous allocations.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew.; Feer, Stefan P.; Rhodes, Zachary D.

    2013-02-01

    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  7. Optimal allocation of reviewers for peer feedback

    DEFF Research Database (Denmark)

    Wind, David Kofoed; Jensen, Ulf Aslak; Jørgensen, Rasmus Malthe

    2017-01-01

    feedback to be effective students should give and receive useful feedback. A key challenge in peer feedback is allocating the feedback givers in a good way. It is important that reviewers are allocated to submissions such that the feedback distribution is fair - meaning that all students receive good......Peer feedback is the act of letting students give feedback to each other on submitted work. There are multiple reasons to use peer feedback, including students getting more feedback, time saving for teachers and increased learning by letting students reflect on work by others. In order for peer...... indicated the quality of the feedback. Using this model together with historical data we calculate the feedback-giving skill of each student and uses that as input to an allocation algorithm that assigns submissions to reviewers, in order to optimize the feedback quality for all students. We test...

  8. Powernext Carbon rises in power

    International Nuclear Information System (INIS)

    Conil-Lacoste, J.F.

    2007-01-01

    Powernext Carbon, the French CO 2 stock exchange, allows industrialists to trade CO 2 emission quotas. Those who have exhausted their allocated quotas can purchase new ones to other industrialists who have emitted less CO 2 than expected. Thanks to Powernext Carbon, the 'polluter pays principle' finally finds a concrete implementation. This article is an interview of J.F. Conil-Lacoste, general director of Powernext, who clarifies some points of the carbon trading system: lessons learnt after 18 months of activity of Powernext Carbon, measures to be implemented to encourage the development of Powernext Carbon, changes made in the 2008-2012 quotas allocation plan of the French government, mechanism of credits for emissions abatement and their role in CO 2 abatement, relevance of a quotas system for individuals. (J.S.)

  9. Large-scale sequestration of atmospheric carbon via plant roots in natural and agricultural ecosystems: why and how.

    Science.gov (United States)

    Kell, Douglas B

    2012-06-05

    The soil holds twice as much carbon as does the atmosphere, and most soil carbon is derived from recent photosynthesis that takes carbon into root structures and further into below-ground storage via exudates therefrom. Nonetheless, many natural and most agricultural crops have roots that extend only to about 1 m below ground. What determines the lifetime of below-ground C in various forms is not well understood, and understanding these processes is therefore key to optimising them for enhanced C sequestration. Most soils (and especially subsoils) are very far from being saturated with organic carbon, and calculations show that the amounts of C that might further be sequestered (http://dbkgroup.org/carbonsequestration/rootsystem.html) are actually very great. Breeding crops with desirable below-ground C sequestration traits, and exploiting attendant agronomic practices optimised for individual species in their relevant environments, are therefore important goals. These bring additional benefits related to improvements in soil structure and in the usage of other nutrients and water.

  10. Large-scale sequestration of atmospheric carbon via plant roots in natural and agricultural ecosystems: why and how

    Science.gov (United States)

    Kell, Douglas B.

    2012-01-01

    The soil holds twice as much carbon as does the atmosphere, and most soil carbon is derived from recent photosynthesis that takes carbon into root structures and further into below-ground storage via exudates therefrom. Nonetheless, many natural and most agricultural crops have roots that extend only to about 1 m below ground. What determines the lifetime of below-ground C in various forms is not well understood, and understanding these processes is therefore key to optimising them for enhanced C sequestration. Most soils (and especially subsoils) are very far from being saturated with organic carbon, and calculations show that the amounts of C that might further be sequestered (http://dbkgroup.org/carbonsequestration/rootsystem.html) are actually very great. Breeding crops with desirable below-ground C sequestration traits, and exploiting attendant agronomic practices optimised for individual species in their relevant environments, are therefore important goals. These bring additional benefits related to improvements in soil structure and in the usage of other nutrients and water. PMID:22527402

  11. Prospect theory reflects selective allocation of attention.

    Science.gov (United States)

    Pachur, Thorsten; Schulte-Mecklenbeck, Michael; Murphy, Ryan O; Hertwig, Ralph

    2018-02-01

    There is a disconnect in the literature between analyses of risky choice based on cumulative prospect theory (CPT) and work on predecisional information processing. One likely reason is that for expectation models (e.g., CPT), it is often assumed that people behaved only as if they conducted the computations leading to the predicted choice and that the models are thus mute regarding information processing. We suggest that key psychological constructs in CPT, such as loss aversion and outcome and probability sensitivity, can be interpreted in terms of attention allocation. In two experiments, we tested hypotheses about specific links between CPT parameters and attentional regularities. Experiment 1 used process tracing to monitor participants' predecisional attention allocation to outcome and probability information. As hypothesized, individual differences in CPT's loss-aversion, outcome-sensitivity, and probability-sensitivity parameters (estimated from participants' choices) were systematically associated with individual differences in attention allocation to outcome and probability information. For instance, loss aversion was associated with the relative attention allocated to loss and gain outcomes, and a more strongly curved weighting function was associated with less attention allocated to probabilities. Experiment 2 manipulated participants' attention to losses or gains, causing systematic differences in CPT's loss-aversion parameter. This result indicates that attention allocation can to some extent cause choice regularities that are captured by CPT. Our findings demonstrate an as-if model's capacity to reflect characteristics of information processing. We suggest that the observed CPT-attention links can be harnessed to inform the development of process models of risky choice. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  12. Allocation of Decommissioning and Waste Liabilities

    International Nuclear Information System (INIS)

    Varley, Geoff

    2011-11-01

    The work demonstrates that there are a number of methods available for cost allocation, the pros and cons of which are examined. The study investigates potential proportional and incremental methods in some depth. A recommendation in principle to use the latter methodology is given. It is concluded that a 'fair assumption' is that the potential allocation of costs for 'the RMA Leaching Hall' probably is small, in relation to the total costs, and estimated to be not more than about 175 kSEK, plus any costs associated with decommissioning/ disposal of a number of small pieces of equipment added by the current operator

  13. Vascularized Composite Allografts: Procurement, Allocation, and Implementation.

    Science.gov (United States)

    Rahmel, Axel

    Vascularized composite allotransplantation is a continuously evolving area of modern transplant medicine. Recently, vascularized composite allografts (VCAs) have been formally classified as 'organs'. In this review, key aspects of VCA procurement are discussed, with a special focus on interaction with the procurement of classical solid organs. In addition, options for a matching and allocation system that ensures VCA donor organs are allocated to the best-suited recipients are looked at. Finally, the different steps needed to promote VCA transplantation in society in general and in the medical community in particular are highlighted.

  14. Resource allocation using ANN in LTE

    Science.gov (United States)

    Yigit, Tuncay; Ersoy, Mevlut

    2017-07-01

    LTE is the 4th generation wireless network technology, which provides flexible bandwidth, higher data speeds and lower delay. Difficulties may be experienced upon an increase in the number of users in LTE. The objective of this study is to ensure a faster solution to any such resource allocation problems which might arise upon an increase in the number of users. A fast and effective solution has been obtained by making use of Artificial Neural Network. As a result, fast working artificial intelligence methods may be used in resource allocation problems during operation.

  15. Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

    Science.gov (United States)

    Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

    2017-12-01

    Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an i