WorldWideScience

Sample records for belowground carbon allocation

  1. The response of belowground carbon allocation in forests to global change

    Science.gov (United States)

    Christian P. Giardina; Mark Coleman; Dan Binkley; Jessica Hancock; John S. King; Erik Lilleskov; Wendy M. Loya; Kurt S. Pregitzer; Michael G. Ryan; Carl Trettin

    2005-01-01

    Belowground carbon allocation (BCA) in forests regulates soil organic matter formation and influences biotic and abiotic properties of soil such as bulk density, cation exchange capacity, and water holding capacity. On a global scale, the total quantity of carbon allocated belowground by terrestrial plants is enormous, exceeding by an order of magnitude the quantity of...

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

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    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...

  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. Rate of belowground carbon allocation differs with successional habit of two afromontane trees.

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    Olga Shibistova

    Full Text Available BACKGROUND: Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO(2 efflux is crucial for addressing the carbon footprint of creeping degradation. METHODOLOGY: We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb. Mirb. and the early successional (gap filling angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree (13CO(2 pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO(2. Further, we quantified the overall losses of assimilated (13C with soil CO(2 efflux. PRINCIPAL FINDINGS: (13C in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon, having a shorter mean residence time (14 h vs. 55 h as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO(2 efflux as in case of P. falcatus (24 h vs. 72 h. Within one year soil CO(2 efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. CONCLUSIONS: Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e.g., by degradation accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may

  5. Rate of belowground carbon allocation differs with successional habit of two afromontane trees.

    Science.gov (United States)

    Shibistova, Olga; Yohannes, Yonas; Boy, Jens; Richter, Andreas; Wild, Birgit; Watzka, Margarethe; Guggenberger, Georg

    2012-01-01

    Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO(2) efflux is crucial for addressing the carbon footprint of creeping degradation. We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb.) Mirb. and the early successional (gap filling) angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree (13)CO(2) pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO(2). Further, we quantified the overall losses of assimilated (13)C with soil CO(2) efflux. (13)C in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon), having a shorter mean residence time (14 h vs. 55 h) as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO(2) efflux as in case of P. falcatus (24 h vs. 72 h). Within one year soil CO(2) efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e.g., by degradation) accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may deplete soil organic carbon in the long run.

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

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    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

  7. Influence of elevated carbon dioxide and temperature on belowground carbon allocation and enzyme activities in tropical flooded soil planted with rice.

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    Bhattacharyya, P; Roy, K S; Neogi, S; Manna, M C; Adhya, T K; Rao, K S; Nayak, A K

    2013-10-01

    Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO2) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO2 condition. However, the relationship between interactive effects of elevated CO2 and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO2 and elevated CO2 + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO2 and elevated CO2 + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO2 + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like β-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.

  8. 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.

  9. Belowground carbon allocation by trees drives seasonal patterns of extracellular enzyme activities by altering microbial community composition in a beech forest soil.

    Science.gov (United States)

    Kaiser, Christina; Koranda, Marianne; Kitzler, Barbara; Fuchslueger, Lucia; Schnecker, Jörg; Schweiger, Peter; Rasche, Frank; Zechmeister-Boltenstern, Sophie; Sessitsch, Angela; Richter, Andreas

    2010-08-01

    *Plant seasonal cycles alter carbon (C) and nitrogen (N) availability for soil microbes, which may affect microbial community composition and thus feed back on microbial decomposition of soil organic material and plant N availability. The temporal dynamics of these plant-soil interactions are, however, unclear. *Here, we experimentally manipulated the C and N availability in a beech forest through N fertilization or tree girdling and conducted a detailed analysis of the seasonal pattern of microbial community composition and decomposition processes over 2 yr. *We found a strong relationship between microbial community composition and enzyme activities over the seasonal course. Phenoloxidase and peroxidase activities were highest during late summer, whereas cellulase and protease peaked in late autumn. Girdling, and thus loss of mycorrhiza, resulted in an increase in soil organic matter-degrading enzymes and a decrease in cellulase and protease activity. *Temporal changes in enzyme activities suggest a switch of the main substrate for decomposition between summer (soil organic matter) and autumn (plant litter). Our results indicate that ectomycorrhizal fungi are possibly involved in autumn cellulase and protease activity. Our study shows that, through belowground C allocation, trees significantly alter soil microbial communities, which may affect seasonal patterns of decomposition processes.

  10. Belowground carbon cycling in a humid tropical forest decreases with fertilization

    Science.gov (United States)

    C. Giardina; D. Binkley; M. Ryan; J. Fownes

    2004-01-01

    Only a small fraction of the carbon (C) allocated belowground by trees is retained by soils in long-lived, decay-resistant forms, yet because of the large magnitude of terrestrial primary productivity, even small changes in C allocation or retention can alter terrestrial C storage. The humid tropics exert a disproportionately large influence over terrestrial C storage...

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

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    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

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

    Science.gov (United States)

    Nie, Xiuqing; 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.

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

    Directory of Open Access Journals (Sweden)

    Xiuqing Nie

    Full Text Available 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.

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

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    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...

  15. 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 ...

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

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    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.

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

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    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.

  18. Accounting for variation in root wood density and percent carbon in belowground carbon estimates

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    Brandon H. Namm; John-Pascal Berrill

    2012-01-01

    Little is known about belowground biomass and carbon in tanoak. Although tanoaks rarely provide merchantable wood, an assessment of belowground carbon loss due to tanoak removal and Sudden Oak Death will inform conservation and management decisions in redwood-tanoak ecosystems.The carbon content of woody biomass is a function of...

  19. Disturbance and decoupling of belowground carbon and nitrogen cycles in a northern temperate forest

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    Nave, L. E.; Nadelhoffer, K.; Le Moine, J.; Hardiman, B. S.; Sparks, J. P.; Strahm, B. D.; Munoz, A.; Gough, C. M.; Vogel, C. S.; Curtis, P.

    2011-12-01

    Belowground carbon (C) and nitrogen (N) cycles are tightly coupled in many northern temperate forests. However, disturbances that cause tree mortality can decouple linkages between belowground components of these biogeochemical cycles. We measured a suite of belowground processes following a treatment to accelerate the natural senescence of early-successional dominants in a northern temperate forest, hypothesizing that tree mortality would decrease belowground C allocation, increase belowground N availability and cycling rates, and trigger N leaching in this highly N-limited forest. In the Forest Accelerated Succession ExperimenT, we stem girdled >6700 aspen and birch trees (39% of basal area) on 40 ha of forestland at the University of Michigan Biological Station to test these and other hypotheses related to forest development and biogeochemistry. Here, we present the cascade of changes in belowground C and N cycling that occurred in the first two growing seasons following initiation of FASET in April 2008. Aspen and birch mortality decreased stand-level fine root nonstructural carbohydrate contents, accelerating fine root turnover and causing a net reduction in fine root biomass. These decreases in belowground C allocation and root functioning increased forest floor net NH4+ availability, which accelerated nitrification rates, increased net NO3- availability, and led to small NO3- leaching losses. These belowground perturbations were registered by the forest canopy through shifts in foliar 13C and 15N natural abundances, which indicated water stress among girdled aspens and faster, leakier cycling in a source N pool shared by foliage of all tree species. We interpret the results of this initial disturbance phase of the FASET study in the context of our conceptual model of N availability and ecosystem C storage over longer-term (successional) time scales. We predict that, following minor N leaching losses during disturbance, reorganization of belowground N cycling

  20. Coupling tree rings and eddy covariance to estimate long-term above and belowground carbon storage at the stand level

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    Dye, A.; Alexander, M. R.; Bishop, D.; Pederson, N.; Hessl, A. E.

    2016-12-01

    Storage of carbon in terrestrial plants and soils directly reduces atmospheric carbon concentration, and it is thereby imperative to improve our understanding of where carbon is being stored and released in an ecosystem and how storages and releases are changing over time. At data-rich sites, coupling alternative measurements of carbon flux can improve this understanding. Here, we present a methodology to inversely model stand-level net storage and release of above- and belowground carbon over a period of 1-2 decades using co-located tree-ring plots and eddy covariance towers at three eastern U.S. forests. We reconstructed annual aboveground wood production (aNPP) from tree rings collected near eddy covariance towers. We compared our aNPP reconstructions with annual tower NEE to address whether interannual variations are correlated. Despite modest correlation, we observed magnitude differences between both records that vary annually. We interpret these differences as indicative of changes in belowground carbon storage, i.e. an aNPP:NEE ratio > 1 indicates a net release of belowground carbon and a ratio carbon. For this interpretation, we assume the following: a) carbon not directed to above or belowground pools is insignificant, b) carbon not stored above ground is stored below ground, and c) mature trees do not add to a storage pool at a higher level every year. While the offset between biometric aNPP and tower NEE could partially be attributed to the diversion of assimilated carbon to nonstructural carbohydrates instead of growth, we argue that this becomes a less important factor over longer time scales in a mature tree. Our approach does not quantify belowground NPP or allocation, but we present a method for estimating belowground carbon storage and release at the stand level, an otherwise difficult task at this scale due to heterogeneity across the stand.

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

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    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 (...

  2. 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).

  3. 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

  4. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

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    L. Barthes

    2011-05-01

    Full Text Available Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objective of our study was to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tuneable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season, and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. It varied between 1 and 21 % of the amount of 13CO2 taken up by the crown, depending on the species and the season. While rainfall exclusion that moderately decreased soil water content did not affect the pattern of carbon allocation to soil CO2 efflux in beech, seasonal patterns of carbon allocation belowground differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with the strength of other sinks (aboveground growth in late spring and storage in late summer that were not observed in oak. We report a fast transfer of recent photosynthates to the mycorhizosphere and we conclude that the

  5. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

    Science.gov (United States)

    Epron, D.; Ngao, J.; Dannoura, M.; Bakker, M. R.; Zeller, B.; Bazot, S.; Bosc, A.; Plain, C.; Lata, J. C.; Priault, P.; Barthes, L.; Loustau, D.

    2011-05-01

    Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objective of our study was to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine) was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tuneable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C) of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6-2.7 days during the active growing season, more than 4 days during the resting season), and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. It varied between 1 and 21 % of the amount of 13CO2 taken up by the crown, depending on the species and the season. While rainfall exclusion that moderately decreased soil water content did not affect the pattern of carbon allocation to soil CO2 efflux in beech, seasonal patterns of carbon allocation belowground differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with the strength of other sinks (aboveground growth in late spring and storage in late summer) that were not observed in oak. We report a fast transfer of recent photosynthates to the mycorhizosphere and we conclude that the patterns of carbon

  6. Root carbon flow from an invasive plant to belowground foodwebs

    Science.gov (United States)

    Mark A. Bradford; Michael S. Strickland; Jayna L. DeVore; John C. Maerz

    2012-01-01

    Aims Soil foodwebs are based on plant production. This production enters belowground foodwebs via numerous pathways, with root pathways likely dominating supply. Indeed, root exudation may fuel 30–50 % of belowground activity with photosynthate fixed only hours earlier. Yet we have limited knowledge of root fluxes of recent-photosynthate from invasive plants to...

  7. Effects of Grazing on Above- vs. Below-Ground Biomass Allocation of Alpine Grasslands on the Northern Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Chaoxu Zeng

    Full Text Available Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010-2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP was represented by the peak AGB while the belowground net primary productivity (BNPP was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying

  8. Effects of Grazing on Above- vs. Below-Ground Biomass Allocation of Alpine Grasslands on the Northern Tibetan Plateau.

    Science.gov (United States)

    Zeng, Chaoxu; Wu, Jianshuang; Zhang, Xianzhou

    2015-01-01

    Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB) values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010-2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP) was represented by the peak AGB while the belowground net primary productivity (BNPP) was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA) and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced) and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA) analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying human

  9. 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

  10. 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

  11. 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

  12. 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.

  13. Summer drought alters carbon allocation to roots and root respiration in mountain grassland.

    Science.gov (United States)

    Hasibeder, Roland; Fuchslueger, Lucia; Richter, Andreas; Bahn, Michael

    2015-02-01

    Drought affects the carbon (C) source and sink activities of plant organs, with potential consequences for belowground C allocation, a key process of the terrestrial C cycle. The responses of belowground C allocation dynamics to drought are so far poorly understood. We combined experimental rain exclusion with (13)C pulse labelling in a mountain meadow to analyse the effects of summer drought on the dynamics of belowground allocation of recently assimilated C and how it is partitioned among different carbohydrate pools and root respiration. Severe soil moisture deficit decreased the ecosystem C uptake and the amounts and velocity of C allocated from shoots to roots. However, the proportion of recently assimilated C translocated belowground remained unaffected by drought. Reduced root respiration, reflecting reduced C demand under drought, was increasingly sustained by C reserves, whilst recent assimilates were preferentially allocated to root storage and an enlarged pool of osmotically active compounds. Our results indicate that under drought conditions the usage of recent photosynthates is shifted from metabolic activity to osmotic adjustment and storage compounds. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  14. Belowground carbon distribution in a pinon-juniper / short grass prairie site

    Science.gov (United States)

    John Harrington

    2008-01-01

    Pinon-juniper woodlands encompass over 22.5 million hectares in the Western United States. However, little is known about the ability of these ecosystems to sequester carbon. This paper presents the preliminary results of an investigation on the belowground carbon distribution in a pinon-juniper/short grass prarie site in north-central New Mexico. Using a systematic...

  15. Fertilization Increases Below-Ground Carbon Sequestration of Loblolly Pine Plantations

    Science.gov (United States)

    K.H. Johnsen; J.R. Butnor; C. Maier; R. Oren; R. Pangle; L. Samuelson; J. Seiler; S.E. McKeand; H.L. Allen

    2001-01-01

    The extent of fertilization of southern pine forests is increasing rapidly; industrial fertilization increased from 16,200 ha per year in 1988, to 344,250 ha in 1998. Fertilization increases stand productivity and can increase carbon (C) sequestration by: 1) increasing above-ground standing C; 2) increasing C stored in forest products; and 3) increasing below-ground...

  16. 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...

  17. Monitoring CO2emissions 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.

  18. Carbon allocation patterns in boreal and hemiboreal forest ecosystems along the gradient of soil fertility

    Science.gov (United States)

    Kriiska, Kaie; Uri, Veiko; Frey, Jane; Napa, Ülle; Kabral, Naima; Soosaar, Kaido; Rannik, Kaire; Ostonen, Ivika

    2017-04-01

    Carbon (C) allocation plays a critical role in forest ecosystem carbon cycling. Changes in C allocation alter ecosystems carbon sequestration and plant-soil-atmosphere gas exchange, hence having an impact on the climate. Currently, there is lack of reliable indicators that show the direction of C accumulation patterns in forest ecosystems on regional scale. The first objective of our study was to determine the variability of carbon allocation in hemiboreal coniferous forests along the gradient of soil fertility in Estonia. We measured C stocks and fluxes, such as litter, fine root biomass and production, soil respiration etc. in 8 stands of different site types - Scots pine (Cladonia, Vaccinium, Myrtillus, Fragaria) and Norway spruce (Polytrichum, Myrtillus, Oxalis, Calamagrostis alvar). The suitability of above- and belowground litter production (AG/BG) ratio was analysed as a carbon allocation indicator. The second aim of the study was to analyse forest C allocation patterns along the north-south gradient from northern boreal Finland to hemiboreal Estonia. Finally, C sequestration in silver birch and grey alder stands were compared with coniferous stands in order to determine the impact of tree species on carbon allocation. Preliminary results indicate that estimated AG/BG ratio (0.5 ... 3.0) tends to decrease with increasing soil organic horizon C/N ratio, indicating that in less fertile sites more carbon is allocated into belowground through fine root growth and in consequence the soil organic carbon stock increases. Similar trends were found on the north-south forest gradient. However, there was a significant difference between coniferous and broadleaf stands in C allocation patterns. Net ecosystem exchange in Estonian coniferous stands varied from -1.64 ... 3.95 t C ha-1 yr-1, whereas older stands tended to be net carbon sources.

  19. 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

  20. 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

  1. 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

  2. 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.

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

    Science.gov (United States)

    Webb, Elizabeth E.; Heard, Kathryn; Natali, Susan M.; Bunn, Andrew G.; Alexander, Heather D.; Berner, Logan T.; Kholodov, Alexander; Loranty, Michael M.; Schade, John D.; Spektor, Valentin; Zimov, Nikita

    2017-09-01

    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 belowground C storage. Thaw depth was negatively related to stand age, and soil C density

  4. 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

  5. Stocks of carbon and nitrogen and partitioning between above- and belowground pools in the Brazilian coastal Atlantic Forest elevation range.

    Science.gov (United States)

    Vieira, Simone A; Alves, Luciana F; Duarte-Neto, Paulo J; Martins, Susian C; Veiga, Larissa G; Scaranello, Marcos A; Picollo, Marisa C; Camargo, Plinio B; do Carmo, Janaina B; Neto, Eráclito Sousa; Santos, Flavio A M; Joly, Carlos A; Martinelli, Luiz A

    2011-11-01

    We estimated carbon and nitrogen stocks in aboveground biomass (AGB) and belowground biomass (BGB) along an elevation range in forest sites located on the steep slopes of the Serra do Mar on the north coast of the State of São Paulo, southeast Brazil. In elevations of 100 m (lowland), 400 m (submontane), and 1000 m (montane) four 1-ha plots were established, and above- (live and dead) and belowground (live and dead) biomass were determined. Carbon and nitrogen concentrations in each compartment were determined and used to convert biomass into carbon and nitrogen stocks. The carbon aboveground stock (C(AGB)) varied along the elevation range from approximately 110 to 150 Mg·ha(-1), and nitrogen aboveground stock (N(AGB)), varied from approximately 1.0 to 1.9 Mg·ha(-1). The carbon belowground stock (C(BGB)) and the nitrogen belowground stock (N(BGB)) were significantly higher than the AGB and varied along the elevation range from approximately 200-300 Mg·ha(-1), and from 14 to 20 Mg·ha(-1), respectively. Finally, the total carbon stock (C(TOTAL)) varied from approximately 320 to 460 Mg·ha(-1), and the nitrogen total stock (N(TOTAL)) from approximately 15 to 22 Mg·ha(-1). Most of the carbon and nitrogen stocks were found belowground and not aboveground as normally found in lowland tropical forests. The above- and belowground stocks, and consequently, the total stocks of carbon and nitrogen increased significantly with elevation. As the soil and air temperature also decreased significantly with elevation, we found a significantly inverse relationship between carbon and nitrogen stocks and temperature. Using this inverse relationship, we made a first approach estimate that an increase of 1°C in soil temperature would decrease the carbon and nitrogen stocks in approximately 17 Mg·ha(-1) and 1 Mg·ha(-1) of carbon and nitrogen, respectively.

  6. 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

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

    Science.gov (United States)

    Brüggemann, N.; Gessler, A.; Kayler, Z.; Keel, S. G.; Badeck, F.; Barthel, M.; Boeckx, P.; Buchmann, N.; Brugnoli, E.; Esperschütz, J.; Gavrichkova, O.; Ghashghaie, J.; Gomez-Casanovas, N.; Keitel, C.; Knohl, A.; Kuptz, D.; Palacio, S.; Salmon, Y.; Uchida, Y.; Bahn, M.

    2011-11-01

    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 CO2 diffusion and dissolution processes within the

  8. Do changes in carbon allocation account for the growth response to potassium and sodium applications in tropical Eucalyptus plantations?

    Science.gov (United States)

    Epron, Daniel; Laclau, Jean-Paul; Almeida, Julio C R; Gonçalves, José Leonardo M; Ponton, Stephane; Sette, Carlos R; Delgado-Rojas, Juan S; Bouillet, Jean-Pierre; Nouvellon, Yann

    2012-06-01

    Understanding the underlying mechanisms that account for the impact of potassium (K) fertilization and its replacement by sodium (Na) on tree growth is key to improving the management of forest plantations that are expanding over weathered tropical soils with low amounts of exchangeable bases. A complete randomized block design was planted with Eucalyptus grandis (W. Hill ex Maiden) to quantify growth, carbon uptake and carbon partitioning using a carbon budget approach. A combination of approaches including the establishment of allometric relationships over the whole rotation and measurements of soil CO(2) efflux and aboveground litterfall at the end of the rotation were used to estimate aboveground net production (ANPP), total belowground carbon flux and gross primary production (GPP). The stable carbon isotope (δ(13)C) of stem wood α-cellulose produced every year was used as a proxy for stomatal limitation of photosynthesis. Potassium fertilization increased GPP and decreased the fraction of carbon allocated belowground. Aboveground net production was strongly enhanced, and because leaf lifespan increased, leaf biomass was enhanced without any change in leaf production, and wood production (P(W)) was dramatically increased. Sodium application decreased the fraction of carbon allocated belowground in a similar way, and enhanced GPP, ANPP and P(W), but to a lesser extent compared with K fertilization. Neither K nor Na affected δ(13)C of stem wood α-cellulose, suggesting that water-use efficiency was the same among the treatments and that the inferred increase in leaf photosynthesis was not only related to a higher stomatal conductance. We concluded that the response to K fertilization and Na addition on P(W) resulted from drastic changes in carbon allocation.

  9. 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.

  10. Belowground carbon dynamics in loblolly pine (Pinus taeda) immediately following diammonium phosphate fertilization.

    Science.gov (United States)

    Gough, Christopher M; Seiler, John R

    2004-07-01

    Forest soils store an immense quantity of labile carbon (C) and a may be a large potential sink for atmospheric C. Forest management practices such as fertilization may enhance overall C storage in soils, yet changes in physiological processes following nutrient amendments have not been widely investigated. We intensively monitored belowground C dynamics for nearly 200 days following diammonium phosphate fertilization of pot-grown loblolly pine (Pinus taeda L.) seedlings in an effort to examine the short-term effects of fertilization on processes involved in soil C sequestration. Soil respiration rates initially increased in fertilized pots relative to controls, followed by a brief reversal in this trend and then a final sustained pattern of elevated rates of soil respiration in the fertilized treatment. Patterns in soil respiration rates over time reflected changes in autotrophic (root) and heterotrophic (microbial) components of soil respiration. Root respiration rates were greater in the fertilized treatment 49 days following fertilization and returned to control rates by the end of the study. In contrast, microbial respiration rates and microbial activity per soil C concentration remained depressed over the same time period. Compared with control seedlings, total root biomass was 27% greater in fertilized seedlings harvested at the end of the study, indicating that the elevated soil respiration rates observed toward the end of the study were a result of increased respiring root biomass. We conclude that fertilization, at least over the short-term, may increase soil C sequestration by increasing belowground biomass production and reducing microbial driven C turnover. Copyright 2004 Heron Publishing

  11. 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.

  12. 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.

  13. 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

  14. LBA-ECO CD-08 Carbon Isotopes in Belowground Carbon Pools, Amazonas and Para, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains carbon isotope signatures from soil organic matter collected from the following sites: the forests of the ZF-2 INPA reserve...

  15. LBA-ECO CD-08 Carbon Isotopes in Belowground Carbon Pools, Amazonas and Para, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains carbon isotope signatures from soil organic matter collected from the following sites: the forests of the ZF-2 INPA reserve approximately 80...

  16. 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...

  17. 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.

  18. 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...

  19. Sedimentation and belowground carbon accumulation rates in mangrove forests that differ in diversity and land use: a tale of two mangroves

    Science.gov (United States)

    Richard A. MacKenzie; Patra B. Foulk; J. Val Klump; Kimberly Weckerly; Joko Purbospito; Daniel Murdiyarso; Daniel C. Donato; Vien Ngoc Nam

    2016-01-01

    Increased sea level is the climate change effect expected to have the greatest impact on mangrove forest survival. Mangroves have survived extreme fluctuations in sea level in the past through sedimentation and belowground carbon (C) accumulation, yet it is unclear what factors may influence these two parameters. We measured sedimentation, vertical accretion, and...

  20. 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

  1. 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).

  2. 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.

  3. Modeling carbon allocation in trees: a search for principles.

    Science.gov (United States)

    Franklin, Oskar; Johansson, Jacob; Dewar, Roderick C; Dieckmann, Ulf; McMurtrie, Ross E; Brännström, Ake; Dybzinski, Ray

    2012-06-01

    We review approaches to predicting carbon and nitrogen allocation in forest models in terms of their underlying assumptions and their resulting strengths and limitations. Empirical and allometric methods are easily developed and computationally efficient, but lack the power of evolution-based approaches to explain and predict multifaceted effects of environmental variability and climate change. In evolution-based methods, allocation is usually determined by maximization of a fitness proxy, either in a fixed environment, which we call optimal response (OR) models, or including the feedback of an individual's strategy on its environment (game-theoretical optimization, GTO). Optimal response models can predict allocation in single trees and stands when there is significant competition only for one resource. Game-theoretical optimization can be used to account for additional dimensions of competition, e.g., when strong root competition boosts root allocation at the expense of wood production. However, we demonstrate that an OR model predicts similar allocation to a GTO model under the root-competitive conditions reported in free-air carbon dioxide enrichment (FACE) experiments. The most evolutionarily realistic approach is adaptive dynamics (AD) where the allocation strategy arises from eco-evolutionary dynamics of populations instead of a fitness proxy. We also discuss emerging entropy-based approaches that offer an alternative thermodynamic perspective on allocation, in which fitness proxies are replaced by entropy or entropy production. To help develop allocation models further, the value of wide-ranging datasets, such as FLUXNET, could be greatly enhanced by ancillary measurements of driving variables, such as water and soil nitrogen availability.

  4. Above- and below-ground carbon stocks in an indigenous tree (Mytilaria laosensis) plantation chronosequence in subtropical China.

    Science.gov (United States)

    Ming, Angang; Jia, Hongyan; Zhao, Jinlong; Tao, Yi; Li, Yuanfa

    2014-01-01

    More than 60% of the total area of tree plantations in China is in subtropical, and over 70% of subtropical plantations consist of pure stands of coniferous species. Because of the poor ecosystem services provided by pure coniferous plantations and the ecological instability of these stands, a movement is under way to promote indigenous broadleaf plantation cultivation as a promising alternative. However, little is known about the carbon (C) stocks in indigenous broadleaf plantations and their dependence on stand age. Thus, we studied above- and below-ground biomass and C stocks in a chronosequence of Mytilaria laosensis plantations in subtropical China; stands were 7, 10, 18, 23, 29 and 33 years old. Our assessments included tree, shrub, herb and litter layers. We used plot-level inventories and destructive tree sampling to determine vegetation C stocks. We also measured soil C stocks by analyses of soil profiles to 100 cm depth. C stocks in the tree layer dominated the above-ground ecosystem C pool across the chronosequence. C stocks increased with age from 7 to 29 years and plateaued thereafter due to a reduction in tree growth rates. Minor C stocks were found in the shrub and herb layers of all six plantations and their temporal fluctuations were relatively small. C stocks in the litter and soil layers increased with stand age. Total above-ground ecosystem C also increased with stand age. Most increases in C stocks in below-ground and total ecosystems were attributable to increases in soil C content and tree biomass. Therefore, considerations of C sequestration potential in indigenous broadleaf plantations must take stand age into account.

  5. 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

  6. 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

  7. 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.

  8. 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.

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

    Science.gov (United States)

    Allen, M. F.

    2011-12-01

    Mycorrhizal fungi represent a large allocation of C to ecosystems, based on indirect measurements (tree girdling) and glasshouse extrapolations. However, we have no direct measures carbon (C) sink, in part because technologies for studying belowground dynamics on time scales at which roots and microbes grow and die have not existed. We initiated new sensor and observation platforms belowground to characterize and quantify belowground dynamics in a California mixed-conifer ecosystem. For the first time, we directly observed growth and mortality of mycorrhizal fungi in situ. We measured soil CO2, T and θ at 5-min intervals into the soil profile. Using our automated minirhizotron (AMR) for hyphal dynamics and the Bartz minirhizotron for longer-term and spatial variation in roots and rhizomorphs, we measured root, rhizomorph, hyphal growth, and belowground phenology up to 4x daily. 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. Because our data were collected at short intervals, we can describe integrative C exchange using the DayCent model for NPP and measured NPP of rhizomorphs, and fungal hyphae. Here, we focused on an arbuscular mycorrhiza dominated meadow and an ectomycorrhizal pine/oak forest at the James Reserve, in southern California. By daily measuring hyphal growth and mortality, we constructed life-span estimates of mycorrhizal hyphae, and from these, C allocation estimates. In the meadow, the NPP was 141g/m2/y, with a productivity of fine root+internal AM fungi of 76.5g C/m2/y, and an estimated 10% of which is AM fungal C allocation (7.7 g/m2/y). Extramatrical AM hyphal peak standing crop was 10g/m2, with a lifespan of 46 days (with active hyphae persisting for ~240 days per year days). Thus, the annual AM fungal allocation was 7.7g C/m2/y internal and 52g/m2/y external, for a net allocation of 84g C/m2/y, or 60% of the estimated NPP. In the

  10. Characterizing drought-induced changes in active microbial communities and recently assimilated carbon transferred belowground in a forest understory

    Science.gov (United States)

    von Rein, Isabell; Kayler, Zachary; Gessler, Arthur

    2013-04-01

    Greenhouse gas induced global warming is expected to result in droughts of longer duration and higher intensity. Since droughts can disturb ecosystem interconnections, the investigation of ecosystem responses is crucial. Nonetheless, little is known about how changes in water availability affect ecosystem interconnections, e.g. the plant-microorganism response towards a drought event. We hypothesize that there is a shift in the microbial community structure and activity under drought when compared to a well-watered control. Moreover, we assume that changes seen at the microbial level are linked to plant carbon (C) assimilation and transport. We expect reduced C assimilation in plants under drought and a subsequent weakening in the coupling between the plant and belowground processes. How do microbial communities that depend on the rhizodeposited C provided by plants react to a reduction in exudate availability? To answer this question, three intact soil monoliths (70x70x20cm) with their natural understory vegetation were taken from a spruce forest in Hainich, Germany and transferred to a climate chamber. Half of the monoliths are exposed to drought whereas the other half is kept well-watered. The monoliths are pulse labeled with 13CO2 and the label is traced through the plant-soil system. Plants, roots and soil are sampled after labeling and analyzed for their isotopic composition. Pyrosequencing and PLFA-SIP (Phospholipid fatty acids stable isotope probing) are performed to detect changes in the microbial community structure and in the composition of the metabolically active microorganisms, respectively. We will discuss our first results concerning the effects of drought on understory carbon partitioning and the impact of drought on carbon availability to soil microorganisms.

  11. Carbon limitation reveals allocation priority to defense compounds in peppermint

    Science.gov (United States)

    Forkelova, Lenka; Unsicker, Sybille; Forkel, Matthias; Huang, Jianbei; Trumbore, Susan; Hartmann, Henrik

    2016-04-01

    Studies of carbon partitioning during insect or pathogen infestation reveal high carbon investment into induced chemical defenses to deter the biotic agent (Baldwin, 1998). However, little is known how carbon investment into chemical defenses changes under abiotic stress such as drought. Drought forces plants to close their stomata to prevent water loss through transpiration while decreasing the amount of assimilated carbon. Furthermore drought hampers carbohydrates translocation due to declining plant hydration and reduced phloem functioning (McDowell, 2011; Hartmann et al., 2013; Sevanto, 2014). Hence long lasting drought can force plants into carbon starvation. The aim of our study was to disentangle carbon allocation priorities between growth, maintenance metabolism, storage and production of defense compounds under carbon limiting conditions using peppermint as our model plant. Drought is not the only method how to manipulate plant carbon metabolism and photosynthetic yield. Exposing plants to reduced [CO2] air is a promising tool simulating drought induced carbon limitation without affecting phloem functioning and so carbohydrate translocation (Hartmann et al., 2015). We exposed peppermint plants to drought (50% of the control irrigation) and to low [CO2] (progressive decrease from 350 ppm to 20 ppm) to disentangle hydraulic failure from carbon starvation effects on carbon allocation. Drought was applied as a cross-treatment yielding four treatments: watered and high [CO2] (W+CO2), drought and high [CO2] (D+CO2), water and low [CO2] (W-CO2), drought and low [CO2] (D-CO2). We analyzed the most abundant terpenoid defense compounds (α-Pinene, sabinene, myrcene, limonene, menthone, menthol and pulegone) and used continuous 13CO2 labelling to trace allocation pattern of new and old assimilated carbon in the four carbon sinks (structural biomass, water soluble sugars, starch and terpenoid defense compounds) in young expanding leaf tissue. This leaf tissue grew

  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. Role of metabolite transporters in source-sink carbon allocation

    Directory of Open Access Journals (Sweden)

    Frank eLudewig

    2013-07-01

    Full Text Available Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g. roots, flowers, small leaves and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartmentalized. Photoassimilates are allocated to distinct compartments of these tissues in all organs, requiring a set of metabolite transporters mediating this intercompartmental transfer.The general route of photoassimilates can be briefly described as follows. Upon fixation of carbon dioxide in chloroplasts of mesophyll cells, triose phosphates either enter the cytosol for mainly sucrose formation or remain in the stroma to form transiently stored starch which is degraded during the night and enters the cytosol as maltose or glucose to be further metabolized to sucrose. In both cases, sucrose enters the phloem for long distance transport or is transiently stored in the vacuole, or can be degraded to hexoses which also can be stored in the vacuole.In the majority of plant species, sucrose is actively loaded into the phloem via the apoplast. Following long distance transport, it is released into sink organs, where it enters cells as source of carbon and energy. In storage organs, sucrose can be stored, or carbon derived from sucrose can be stored as starch in plastids, or as oil in oil bodies, or - in combination with nitrogen - as protein in protein storage vacuoles and protein bodies.Here, we focus on transport proteins known for either of these steps, and discuss the implications for yield increase in plants upon genetic engineering of respective transporters.

  14. 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.

  15. 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

  16. Total below-ground carbon and nitrogen partitioning of mature black spruce displaying genetic x soil moisture interaction in growth

    Science.gov (United States)

    John E. Major; Kurt H. Johnsen; Debby C. Barsi; Moira Campbell

    2012-01-01

    Total belowground biomass, soil C, and N mass were measured in plots of 32-year-old black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) from four full-sib families studied previously for drought tolerance and differential productivity on a dry and a wet site. Stump root biomass was greater on the wet than on the dry site;...

  17. Effect of different crop management systems on net primary productivity and relative carbon allocation coefficients for corn (Zea mays L.

    Directory of Open Access Journals (Sweden)

    S. Khorramdel

    2016-04-01

    coefficients to seed, shoot, root and extra-root were estimated as 0.10-0.17, 0.19-0.52, 0.23-0.39 and 0.15-0.25, respectively. Low input with cow manure application increased allocated carbon to seed, root and extra-root and decreased allocated carbon to shoot. The highest allocated carbon to root observed in low input with using manure (6.5 g C m-2.yr-1 and the lowest allocated carbon to root was in high input (2.7 g C m-2.yr-1. The maximum and the minimum NPP were obtained in low input with cow manure application (16.6 g C m-2.yr-1 and high input (8.9 g C m-2.yr-1, respectively. It seems that crop management system based on low input of cow manure application enhanced carbon allocation to below-ground biomass of corn due to improvement in soil physical, chemical and biological properties and also nutrient availability which could be regarded as an alternative to reduce CO2 production and moderate climate changes.

  18. Innovative Carbon Allowance Allocation Policy for the Shenzhen Emission Trading Scheme in China

    Directory of Open Access Journals (Sweden)

    Bin Ye

    2015-12-01

    Full Text Available The initial allocation of tradable carbon emission allowances is among the most contentious issues in developing an emission trading scheme (ETS. China faces serious dilemmas of system complexity and information incompleteness and asymmetry in allocating carbon allowance among enterprises. As one of the pilot ETS regions, Shenzhen has launched the first regional cap-and-trade ETS (SZ ETS in China. Adhering to the overall plan and classification analysis, SZ ETS intends to solve the aforementioned dilemmas by developing innovative allowance allocation policies. A fundamental principle is to allocate allowances based on carbon intensity and actual output, according to which a two-step allocation procedure is constructed. A competitive game mechanism is introduced for allowance allocation among manufacturing enterprises. Empirical results indicate the following: (1 Carbon allowance allocation based on carbon intensity and actual output can mitigate carbon emission growth by reducing CO2 emitted per unit output, and, thus, buffer the shocks of unexpected economic fluctuations to ETS stability; (2 Competitive game allocation may contribute to improving the use of scattered information to enhance the efficiency of information and emission resource allocation. Exploring SZ ETS may provide a reference for formulating future national carbon allowance allocation policies in China and other developing regions.

  19. Examining Carbon Acquisition and Allocation in Coccolithophores: Carbon Accounting to Understand Paleoproductivity.

    Science.gov (United States)

    Phelps, S. R.; Polissar, P. J.; Stoll, H. M.; deMenocal, P. B.

    2014-12-01

    It is increasingly clear that coccolithophores actively manage their growth and carbon allocation in response to changing environmental conditions. For example, recent work has identified carbon-concentrating mechanisms in coccolithophores—in which the organisms actively enhance the abundance of CO2 in the chloroplast by pumping in bicarbonate—as the source of vital isotope effects in coccolith calcite. Understanding the record for and consequences of this management in the geologic record remains challenging. Here we examine the geometry and geochemistry of coccoliths in surface sediments from the deep ocean to relate these measurements to the modern growth environment in the surface ocean. In this core-top dataset that spans a wide range of environmental and oceanographic settings, we measure the size and thickness of coccolith plates, the trace metal and stable isotopic carbon in coccolith calcite, as well as determine alkenone biomarker fluxes and alkenone carbon isotopic composition (ɛp). This holistic approach aims to elucidate the carbon acquisition and allocation strategies employed by modern coccolithophores and ultimately provide a better framework for interpreting paleoproductivity. This method may provide insight into the growth rate and carbon allocation of coccoliths in the past, and may improve our understanding of the influence of atmospheric CO2 on coccolithophore communities.

  20. 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

  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. 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.

  4. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    Directory of Open Access Journals (Sweden)

    L. E. O. C. Aragão

    2009-12-01

    Full Text Available The net primary productivity (NPP of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1 How do Amazonian forests allocate productivity among its above- and below-ground components? (2 How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error, at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

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

    Science.gov (United States)

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

    2013-01-01

    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 (14C) ‘bomb spike’ as a tracer of substrate and age of carbon in stemwood NSC, CO2 emitted by stems, tree...

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

    Science.gov (United States)

    Andrei G. ​Lapenis; Gregory B. Lawrence; Alexander Heim; Chengyang Zheng; Walter. Shortle

    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...

  7. Evaluation of carbon stocks in above- and below-ground biomass in Central Africa: case study of Lesio-louna tropical rainforest of Congo

    Science.gov (United States)

    Liu, X.; Ekoungoulou, R.; Loumeto, J. J.; Ifo, S. A.; Bocko, Y. E.; Koula, F. E.

    2014-07-01

    The study was aimed to estimate the carbon stocks of above- and below-ground biomass in Lesio-louna forest of Congo. The methodology of allometric equations was used to measure the carbon stocks of Lesio-louna natural forest. We are based precisely on the model II which is also called non-destructive method or indirect method of measuring carbon stocks. While there has been use of parameters such as the DBH and wood density. The research was done with 22 circular plots each 1256 m2. In the 22 plots studied, 19 plots are in the gallery forest and three plots in the secondary forest. Also, 22 circular plots were distributed in 5 sites studies of Lesio-louna forest, including: Inkou forest island, Iboubikro, Ngoyili, Blue lake and Ngambali. So, there are two forest types (secondary forest and gallery forest) in this forest ecosystem. In the 5 sites studied, we made measurements on a total of 347 trees with 197 trees for the class of 10-30 cm diameter, 131 trees for the class of 30-60 cm diameter and 19 trees in the diameter class > 60 cm. The results show that in the whole forest, average carbon stock for the 22 plots of the study was 168.601 t C ha-1 for AGB, or 81% and 39.551 t C ha-1 for BGB, or 19%. The total carbon stocks in all the biomass was 3395.365 t C for AGB, which is 3.395365 × 10-6 Gt C and 909.689934 t C for BGB, which was 9.09689934 × 10-7 Gt C. In this forest, the carbon stock was more important in AGB compared to BGB with respectively 3395.365 t C against 909.689934 t C. Plot10 (AGB = 363.899 t C ha-1 and BGB = 85.516 t C ha-1) was the most dominant in terms of carbon quantification in Lesio-louna.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Optimization and allocation of spinning reserves in a low-carbon framework

    OpenAIRE

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

    2016-01-01

    Low-carbon electric power systems are often characterized by high shares of renewables, such as wind power. The variable nature and limited predictability of some renewables will require novel system operation methods to properly size and cost-efficiently allocate the required reserves. The current state-of-the-art stochastic unit commitment models internalize this sizing and allocation process by considering a set of scenarios representing the stochastic input during the unit commitment opti...

  13. 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

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

    DEFF Research Database (Denmark)

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

    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...... may affect the supply of carbon and energy to the soil microbial population and subsequently alter decomposition and mineralization, important ecosystem processes in carbon and nutrient cycling. In this study, carried out within the cross-European research project CLIMOOR, the effect of climate change...... in the growing season. Differences in climate, soil, and plant characteristics resulted in a gradient in the severity of the drought effects on net carbon uptake by plants with the impact being most severe in Spain, followed by Denmark, with the UK showing few negative effects at significance levels of p less...

  15. Carbon Leakage, Free Allocation and Linking Emissions Trading Schemes

    NARCIS (Netherlands)

    Tiche, Fitsum G.; Weishaar, Stefan E.; Couwenberg, Oscar

    2014-01-01

    A sub-global emissions trading scheme (ETS) risks harming competitiveness and causing carbon leakage. These concerns cast doubt on the efficiency and environmental effectiveness of unilateral climate policies. ETSs implemented thus far include measures to address competitiveness and leakage

  16. Belowground response to drought in a tropical forest soil. II. Change in microbial function impacts carbon composition.

    Directory of Open Access Journals (Sweden)

    Nick eBouskill

    2016-03-01

    Full Text Available 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 the feedback of any shift in functional potential on ecosystem properties related to carbon cycling are poorly understood. Here we show that drought-induced changes in microbial functional diversity and activity shape, and are in turn shaped by, the composition of dissolved and soil-associated carbon. We also demonstrate that a shift in microbial functional traits that favor the production of hygroscopic compounds alter the efflux of carbon dioxide following soil rewetting. Under drought the composition of the dissolved organic carbon pool changed in a manner consistent with a microbial metabolic response. We hypothesize that this microbial ecophysiological response to changing soil moisture elevates the intracellular carbon demand stimulating extracellular enzyme production, that prompts the observed decline in more complex carbon compounds (e.g., cellulose and lignin. Furthermore, a metabolic response to drought appeared to condition (biologically and physically the soil, notably through the production of polysaccharides, particularly in experimental plots that had been pre-exposed to a short-term drought. This hysteretic response, in addition to an observed drought-related decline in phosphorus concentration, may have been responsible for a comparatively modest CO2 efflux following wet-up in drought plots relative to control plots.

  17. Belowground Response to Drought in a Tropical Forest Soil. II. Change in Microbial Function Impacts Carbon Composition.

    Science.gov (United States)

    Bouskill, Nicholas J; Wood, Tana E; Baran, Richard; Hao, Zhao; Ye, Zaw; Bowen, Ben P; Lim, Hsiao Chien; Nico, Peter S; Holman, Hoi-Ying; Gilbert, Benjamin; Silver, Whendee L; Northen, Trent R; Brodie, Eoin L

    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, the feedback of any shift in functional potential on ecosystem properties related to carbon cycling are poorly understood. Here we show that drought-induced changes in microbial functional diversity and activity shape, and are in turn shaped by, the composition of dissolved and soil-associated carbon. We also demonstrate that a shift in microbial functional traits that favor the production of hygroscopic compounds alter the efflux of carbon dioxide following soil rewetting. Under drought the composition of the dissolved organic carbon pool changed in a manner consistent with a microbial metabolic response. We hypothesize that this microbial ecophysiological response to changing soil moisture elevates the intracellular carbon demand stimulating extracellular enzyme production, that prompts the observed decline in more complex carbon compounds (e.g., cellulose and lignin). Furthermore, a metabolic response to drought appeared to condition (biologically and physically) the soil, notably through the production of polysaccharides, particularly in experimental plots that had been pre-exposed to a short-term drought. This hysteretic response, in addition to an observed drought-related decline in phosphorus concentration, may have been responsible for a comparatively modest CO2 efflux following wet-up in drought plots relative to control plots.

  18. Effects of canopy tree species on belowground biogeochemistry in a lowland wet tropical forest

    Science.gov (United States)

    Keller, Adrienne B.; Reed, Sasha C.; Townsend, Alan R.; Cleveland, Cory C.

    2013-01-01

    Tropical rain forests are known for their high biological diversity, but the effects of plant diversity on important ecosystem processes in this biome remain unclear. Interspecies differences in both the demand for nutrients and in foliar and litter nutrient concentrations could drive variations in both the pool sizes and fluxes of important belowground resources, yet our understanding of the effects and importance of aboveground heterogeneity on belowground biogeochemistry is poor, especially in the species-rich forests of the wet tropics. To investigate the effects of individual tree species on belowground biogeochemical processes, we used both field and laboratory studies to examine how carbon (C), nitrogen (N), and phosphorus (P) cycles vary under nine different canopy tree species – including three legume and six non-legume species – that vary in foliar nutrient concentrations in a wet tropical forest in southwestern Costa Rica. We found significant differences in belowground C, N and P cycling under different canopy tree species: total C, N and P pools in standing litter varied by species, as did total soil and microbial C and N pools. Rates of soil extracellular acid phosphatase activity also varied significantly among species and functional groups, with higher rates of phosphatase activity under legumes. In addition, across all tree species, phosphatase activity was significantly positively correlated with litter N/P ratios, suggesting a tight coupling between relative N and P inputs and resource allocation to P acquisition. Overall, our results suggest the importance of aboveground plant community composition in promoting belowground biogeochemical heterogeneity at relatively small spatial scales.

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

    Science.gov (United States)

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

    2016-02-02

    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 and its processes is, therefore, necessary to better understand its current state and predict its future state. We combine a diagnostic ecosystem carbon model with satellite observations of leaf area and biomass (where and when available) and soil carbon data to retrieve the first global estimates, to our knowledge, of carbon cycle state and process variables at a 1° × 1° resolution; retrieved variables are independent from the plant functional type and steady-state paradigms. Our results reveal global emergent relationships in the spatial distribution of key carbon cycle states and processes. Live biomass and dead organic carbon residence times exhibit contrasting spatial features (r = 0.3). Allocation to structural carbon is highest in the wet tropics (85-88%) in contrast to higher latitudes (73-82%), where allocation shifts toward photosynthetic carbon. Carbon use efficiency is lowest (0.42-0.44) in the wet tropics. We find an emergent global correlation between retrievals of leaf mass per leaf area and leaf lifespan (r = 0.64-0.80) that matches independent trait studies. We show that conventional land cover types cannot adequately describe the spatial variability of key carbon states and processes (multiple correlation median = 0.41). This mismatch has strong implications for the prediction of terrestrial carbon dynamics, which are currently based on globally applied parameters linked to land cover or plant functional types.

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

    Science.gov (United States)

    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 and its processes is, therefore, necessary to better understand its current state and predict its future state. We combine a diagnostic ecosystem carbon model with satellite observations of leaf area and biomass (where and when available) and soil carbon data to retrieve the first global estimates, to our knowledge, of carbon cycle state and process variables at a 1° × 1° resolution; retrieved variables are independent from the plant functional type and steady-state paradigms. Our results reveal global emergent relationships in the spatial distribution of key carbon cycle states and processes. Live biomass and dead organic carbon residence times exhibit contrasting spatial features (r = 0.3). Allocation to structural carbon is highest in the wet tropics (85–88%) in contrast to higher latitudes (73–82%), where allocation shifts toward photosynthetic carbon. Carbon use efficiency is lowest (0.42–0.44) in the wet tropics. We find an emergent global correlation between retrievals of leaf mass per leaf area and leaf lifespan (r = 0.64–0.80) that matches independent trait studies. We show that conventional land cover types cannot adequately describe the spatial variability of key carbon states and processes (multiple correlation median = 0.41). This mismatch has strong implications for the prediction of terrestrial carbon dynamics, which are currently based on globally applied parameters linked to land cover or plant functional types. PMID:26787856

  1. Dynamic belowground ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W. F.; Santantonio, D.; McGinty, D.

    1979-01-01

    Roots comprise the primary interface between plant and soil for uptake of water and nutrients. Much is known about the biochemistry, cell physiology and membrane physics associated with these important processes. In this paper we discuss the role of the belowground ecosystem, especially the autotrophic root component, in the structure and function of forest ecosystems. Beyond recognizing roles of anchoring terrestrial plants and uptake of water and nutrients, this component of the forest has been largely neglected in an ecosystem context. In order to focus discussion on the properties of the belowground ecosystem, we use the term rhizosphere to include roots, mycorrhizae, microbes, and rhizophagus invertebrates.

  2. 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,...

  3. Productivity and carbon allocation in pure and mixed-species plantations of Eucalyptus grandis and Acacia mangium in Brazil

    Science.gov (United States)

    Nouvellon, Y.; Laclau, J.; Epron, D.; Le Maire, G.; Gonçalves, J.; Bouillet, J.

    2010-12-01

    Nitrogen fertilizer inputs are required in fast growing eucalypt plantations to meet tree requirements, and to compensate for the large nitrogen outputs associated with wood exportation at the end of the short rotations. Due to the economic and potential environmental cost of fertilizers, mixed-species plantations (MSP) with N-fixing species (NFS) such as Acacia sp. might be an attractive option to improve the long-term soil N (and possibly soil carbon) status. In such MSP, increases in N availability may influence the productivity and C partitioning of the non-N fixing species. To investigate the effects of NFS on nutrient cycling, wood production, C sequestration, and soil fertility, a randomized block design including monocultures of Eucalyptus grandis (100%E) and Acacia mangium (100%A), and mixtures of these species (50%E:50%A) was set up in southern Brazil. Our specific goals in the present study were to compare the production and C allocation patterns of these plantations, during the two last years of the 6-yr rotation. We hypothesized that 1) a large part of the differences in wood production between monospecific stands would be explained by differences in C allocation; and 2) the C allocation patterns of each species would be strongly modified in mixed- species plantations compared to mono-specific plantations due to inter-specific interactions and shifts in soil N status. Biomass increase (growth, G) in the different plant compartments was assessed by means of inventories and allometric relationships. Total aboveground net primary productivity (ANPP), and the productivity of each aboveground plant compartment were estimated from measurements of G and litterfall (L) (ANPP=G+L). Total belowground C allocations (TBCA) were estimated using a mass-balance approach as soil CO2 efflux C minus the C input from aboveground litter plus changes in the C stored in roots, in the forest floor litter layer, and in soil. Over this first rotation, mixing NFS with eucalypt

  4. Seasonal evolution of carbon allocation to biomass in a French beech forest.

    Science.gov (United States)

    Heid, Laura; Calvaruso, Christophe; Conil, Sébastien; Turpault, Marie-Pierre; Longdoz, Bernard

    2015-04-01

    The objective of this study is to get a better understanding of ecosystem behavior in term of assimilated carbon (C) use. In the global climate change context, this C allocation could play a critical role in predicting ecosystems long terms emissions (Trumbore 2006) and has become a major goal of several emergent studies The monthly C allocation has been determined for a 50-year old beech forest located in north-east of France through the quantification of Gross Primary Production (GPP), biomass production and some of its components (holocelluloses, lignin). In a second phase, the potential factors influencing those productions and allocations throughout a year have been assessed. The temporal evolution of GPP was obtained from the partitioning of eddy-covariance flux measurements and monitored for one year. It was connected to tree aboveground C biomass growth at a monthly step. To achieve the latter, site specific allometric equations were used with trees diameter at breast height (DBH) measured monthly during the growing season on one hand and, on the other hand, C concentrations were deduced from analyses on trunk cores (sampled monthly) and on leaves and bulk branches cores (sampled at the beginning and at the end of the growing season). The C allocated to the aboveground biomass was then estimated, along with the portion allocated to structural C. The results show the delay existing between the end of the tree growth and carbon assimilation. We analyze the possibility to explain this divergence by a compensation coming from the C concentration evolution. Keywords: Carbon allocation, Forest, Biomass production, Carbon concentration, Eddy Covariance Trumbore S. 2006. Carbon Respired by Terrestrial Ecosystems - Recent Progress and Challenges. Global Change Biology 12 (2): 141-53.

  5. Stem girdling indicates prioritized carbon allocation to the root system at the expense of radial stem growth in Norway spruce under drought conditions.

    Science.gov (United States)

    Oberhuber, Walter; Gruber, Andreas; Lethaus, Gina; Winkler, Andrea; Wieser, Gerhard

    2017-06-01

    The early culmination of maximum radial growth (RG) in late spring has been found in several coniferous species in a dry inner Alpine environment. We hypothesized that an early decrease in RG is an adaptation to cope with drought stress, which might require an early switch of carbon (C) allocation to belowground organs. To test this hypothesis, we experimentally subjected six-year-old Norway spruce saplings (tree height: 1.35 m; n = 80 trees) to two levels of soil water availability (watered versus drought conditions) and manipulated tree C status by physically blocking phloem transport at three girdling dates (GD). The influence of C availability and drought on tree growth (radial and shoot growth; root biomass) in response to girdling was analyzed in both treatments. Non-structural carbohydrates (NSCs, soluble sugars and starch) were measured in the stem, root and current leader to evaluate changes in tree C status due to girdling. The main finding was a significant increase in RG of the girdled trees compared to the controls above the girdling zone (UZ). At all girdling dates the RG increase was significantly more intense in the drought-stressed compared with watered trees ( c . 3.3 and 1.9-fold higher compared with controls in the drought-stressed and watered trees, respectively), most likely indicating that an early switch of C allocation to belowground occurs as an adaptation to maintain tree water status under drought conditions. Reactivation of the cambium after the cessation of its regular activity was detected in UZ in drought-stressed trees, while below the girdling zone no xylem formation was found and the NSC content was strikingly reduced. Irrespective of water availability, girdling before growth onset significantly reduced the progression of bud break ( P < 0.05) and the length of the current leader shoot by -47% ( P < 0.01) indicating a reduction in xylem hydraulic conductance, which was corroborated by significantly reduced xylem sap flow ( P < 0

  6. 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.

  7. Estimating belowground carbon stocks in peatlands of the Ecuadorian páramo using ground-penetrating radar (GPR)

    Science.gov (United States)

    Xavier Comas; Neil Terry; John A. Hribljan; Erik A. Lilleskov; Esteban Suarez; Rodney A. Chimner; Randy K. Kolka

    2017-01-01

    The páramo ecoregion of Ecuador contains extensive peatlands that are known to contain carbon (C) dense soils capable of long-term C storage. Although high-altitude mountain peatlands are typically small when compared to low-altitude peatlands, they are abundant across the Andean landscape and are likely a key component in regional C cycling. Since efforts to quantify...

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  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. 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

  16. Seasonal variations of the amount of carbon allocated to respiration after in situ 13CO2 pulse labelling of trees (Invited)

    Science.gov (United States)

    Epron, D.; Dannoura, M.; Ngao, J.; Plain, C.; Berveller, D.; Chipeaux, C.; Gerant, D.; Bosc, A.; Maillard, P.; Loustau, D.; Damesin, C.; Cats Project (Anr-07-Blan-0109)

    2010-12-01

    Soil and trunk respiration are the major sources of carbon from forest ecosystems to the atmosphere and they account for a large fraction of total ecosystem respiration. The amount of photosynthate allocated to respiration affects the growth of the tree and the potential for carbon sequestration of forest ecosystems. This study, aiming at understanding patterns of carbon allocation to respiration among species and seasons, consisted in pure 13CO2 labelling of the entire crown of three different tree species (beech, oak and pine) at distinct phenological stages between Sept 2008 and Feb 2010. 13C was then tracked for several weeks in soil and trunk CO2 efflux at high temporal resolution using tuneable diode laser absorption spectrometry (Plain et al. 2009). Recovery of 13C in trunk and soil CO2 efflux was observed a few couple of hours after the beginning of the labelling in oak and beech. There is a rapid transfer of 13C belowground with a maximum occurring within 2 to 4 days after labelling. Label was recovered at the same time in the respiration and in the biomass of both fine roots and microbes. Maximum recovery occurred earlier in beech and oak, while it happened later in Pine. Indeed, the velocity of phloem transport, calculated as the difference of time lags in 13C recovery in trunk respiration at different height, was around 0.10-0.2m/h in pine and around 0.2-1.2 m/h in oak and beech, reflecting difference in phloem anatomy between angiosperm and gymnosperm. The cumulated amount of label recovered in soil CO2 efflux 20 days after labelling varied among the seasons in all species, from 1 to 16% in beech, 2 to 11% in oak and 1 to 11% in pine. For all species, allocation to soil respiration was greater in early summer compared to spring, late summer and autumn. A compartmental analysis is further conducted to characterise functional pools of labelled substrates and storage compounds that contribute to both trunk and soil respiration. [Plain C, Gérant D

  17. 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.

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

    Science.gov (United States)

    Lapenis, Andrei; Lawrence, Gregory; Buyantuev, Alexander

    2015-04-01

    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.

  19. 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.

  20. Release of resource constraints allows greater carbon allocation to secondary metabolites and storage in winter wheat.

    Science.gov (United States)

    Huang, Jianbei; Hammerbacher, Almuth; Forkelová, Lenka; Hartmann, Henrik

    2017-05-01

    The atmospheric CO 2 concentration ([CO 2 ]) is rapidly increasing, and this may have substantial impact on how plants allocate metabolic resources. A thorough understanding of allocation priorities can be achieved by modifying [CO 2 ] over a large gradient, including low [CO 2 ], thereby altering plant carbon (C) availability. Such information is of critical importance for understanding plant responses to global environmental change. We quantified the percentage of daytime whole-plant net assimilation (A) allocated to night-time respiration (R), structural growth (SG), nonstructural carbohydrates (NSC) and secondary metabolites (SMs) during 8 weeks of vegetative growth in winter wheat (Triticum aestivum) growing at low, ambient and elevated [CO 2 ] (170, 390 and 680 ppm). R/A remained relatively constant over a large gradient of [CO 2 ]. However, with increasing C availability, the fraction of assimilation allocated to biomass (SG + NSC + SMs), in particular NSC and SMs, increased. At low [CO 2 ], biomass and NSC increased in leaves but decreased in stems and roots, which may help plants achieve a functional equilibrium, that is, overcome the most severe resource limitation. These results reveal that increasing C availability from rising [CO 2 ] releases allocation constraints, thereby allowing greater investment into long-term survival in the form of NSC and SMs. © 2016 John Wiley & Sons Ltd.

  1. 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

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

    Science.gov (United States)

    Imbuzeiro, H. A.

    2016-12-01

    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 and nutrient cycling.

  3. 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.

  4. Remotely-sensed indicators of N-related biomass allocation in Schoenoplectus acutus

    Science.gov (United States)

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

    2014-01-01

    Coastal marshes depend on belowground biomass of roots and rhizomes to contribute to peat and soil organic carbon, accrete soil and alleviate flooding as sea level rises. For nutrient-limited plants, eutrophication has either reduced or stimulated belowground biomass depending on plant biomass allocation response to fertilization. Within a freshwater wetland impoundment receiving minimal sediments, we used experimental plots to explore growth models for a common freshwater macrophyte, Schoenoplectus acutus. We used N-addition and control plots (4 each) to test whether remotely sensed vegetation indices could predict leaf N concentration, root:shoot ratios and belowground biomass of S. acutus. Following 5 months of summer growth, we harvested whole plants, measured leaf N and total plant biomass of all above and belowground vegetation. Prior to harvest, we simulated measurement of plant spectral reflectance over 164 hyperspectral Hyperion satellite bands (350–2500 nm) with a portable spectroradiometer. N-addition did not alter whole plant, but reduced belowground biomass 36% and increased aboveground biomass 71%. We correlated leaf N concentration with known N-related spectral regions using all possible normalized difference (ND), simple band ratio (SR) and first order derivative ND (FDN) and SR (FDS) vegetation indices. FDN1235, 549 was most strongly correlated with leaf N concentration and also was related to belowground biomass, the first demonstration of spectral indices and belowground biomass relationships. While S. acutus exhibited balanced growth (reduced root:shoot ratio with respect to nutrient addition), our methods also might relate N-enrichment to biomass point estimates for plants with isometric root growth. For isometric growth, foliar N indices will scale equivalently with above and belowground biomass. Leaf N vegetation indices should aid in scaling-up field estimates of biomass and assist regional monitoring.

  5. Auction design for the allocation of carbon emission allowances: Uniform or discriminatory price?

    Energy Technology Data Exchange (ETDEWEB)

    Cong, R.G. [Chinese Academy of Sciences, Beijing (China); Beijing Inst. of Tech., Bejing (China); Wei, Y.M. [Beijing Inst. of Tech. (China)

    2010-07-01

    The Kyoto Protocol has set emission reduction targets of 5.2% of 1990 levels for six greenhouse gases for thirty-eight OECD countries and transition economies for the commitment period of 2008-2012. To help member states achieve the reduction targets at low cost, the Kyoto Protocol introduced three flexible mechanisms: (1) Emission Trading (ET); (2) Joint Implementation (JI); and (3) Clean Development Mechanism (CDM). In ET, how initial carbon allowances can be distributed among enterprises in a fair way to achieve the greenhouse gas emissions reduction targets is an important issue. The initial allocation of carbon allowances is the basis for designing the carbon emissions trading system. Methods studied by researchers include grandfathering (giving companies permits based on historical output or emissions), auction and the combination of these two modes. Carbon emission rights are essentially a kind of public goods. The free grandfathering allocation modes are neither efficient nor fair. On the other hand, the carbon auction provides a so-called 'double dividend effect'. Under an auction mechanism, carbon allowances are allocated to the agents who need them most, allowing exploitation of their economic value. The auction revenue can be used to finance environmental protection programs, reducing the tax burden otherwise needed for such measures. In designing the carbon auction, which factors are critical and which auction format is better are the issues of interest and which are addressed here. 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

  6. 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

  7. 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.

  8. 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.

  9. Modelling black spruce primary production and carbon allocation in the Quebec boreal forest

    Science.gov (United States)

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

    2017-04-01

    Boreal ecosystems are crucial carbon stores that must be urgently quantified and preserved. Their future evolution is extremely important for the global carbon budget. Here, we will show the progresses achieved with the MAIDEN forest ecophysiological model in simulating carbon fluxes of black spruce (Picea mariana (Mill.) B.S.P.) forests, the most representative ecosystem of the North American boreal biome. Starting from daily minimum-maximum air temperature, precipitation and CO2 atmospheric concentration, MAIDEN models the phenological (5 phenological phases are simulated each year) and meteorological controls on gross primary production (GPP) and carbon allocation to stem. The model is being calibrated on eddy covariance and tree-ring data. We will discuss the model's performance and the modifications introduced in MAIDEN to adapt the model to temperature sensitive forests of the boreal region.

  10. Mechanisms driving carbon allocation in tropical rainforests: allometric constraints and environmental responses

    Science.gov (United States)

    Hofhansl, Florian; Schnecker, Jörg; Singer, Gabriel; Wanek, Wolfgang

    2014-05-01

    Tropical forest ecosystems play a major role in global water and carbon cycles. However, mechanisms of C allocation in tropical forests and their response to environmental variation are largely unresolved as, due to the scarcity of data, they are underrepresented in global syntheses of forest C allocation. Allocation of gross primary production to wood production exerts a key control on forest C residence time and biomass C turnover, and therefore is of special interest for terrestrial ecosystem research and earth system science. Here, we synthesize pantropical data from 105 old-growth rainforests to investigate relationships between climate (mean annual precipitation, mean annual temperature, dry season length and cloud cover), soil nutrient relations (soil N:P) and the partitioning of aboveground net primary production (ANPP) to wood production (WPart) using structural equation modelling. Our results show a strong increase of WPart with ANPP, pointing towards allometric scaling controls on WPart, with increasing light competition in more productive forests triggering greater ANPP allocation to wood production. ANPP itself was positively affected by mean annual temperature and soil N:P. Beyond these allometric controls on WPart we found direct environmental controls. WPart increased with dry season length in tropical montane rainforests and with mean annual precipitation in lowland tropical rainforests. We discuss different trade-offs between plant traits, such as community-wide changes along the wood economics spectrum, the leaf economics spectrum and the plant resource economics spectrum, as underlying mechanisms for direct climatic controls on WPart. We thereby provide new insights into mechanisms driving carbon allocation to WPart in tropical rainforests and show that low and high productive tropical rainforests may respond differently to projected global changes.

  11. 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.

  12. New insights into carbon allocation by trees from the hypothesis that annual wood production is maximized.

    Science.gov (United States)

    McMurtrie, Ross E; Dewar, Roderick C

    2013-09-01

    Allocation of carbon (C) between tree components (leaves, fine roots and woody structures) is an important determinant of terrestrial C sequestration. Yet, because the mechanisms underlying C allocation are poorly understood, it is a weak link in current earth-system models. We obtain new theoretical insights into C allocation from the hypothesis (MaxW) that annual wood production is maximized. MaxW is implemented using a model of tree C and nitrogen (N) balance with a vertically resolved canopy and root system for stands of Norway spruce (Picea abies). MaxW predicts optimal vertical profiles of leaf N and root biomass, optimal canopy leaf area index and rooting depth, and the associated optimal pattern of C allocation. Key insights include a predicted optimal C-N functional balance between leaves at the base of the canopy and the deepest roots, according to which the net C export from basal leaves is just sufficient to grow the basal roots required to meet their N requirement. MaxW links the traits of basal leaves and roots to whole-tree C and N uptake, and unifies two previous optimization hypotheses (maximum gross primary production, maximum N uptake) that have been applied independently to canopies and root systems. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  13. 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.

  14. 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...... manufacturing industry is presented to elucidate the effectiveness of the proposed model. The results demonstrate a 26.2 % reduction of carbon emission by using recycle products in the production process. The firm benefits by forming a systematic methodology for green supplier evaluation and order allocation...

  15. Carbon allocation, sequestration and carbon dioxide mitigation under plantation forests of north western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Bandana Devi

    2013-07-01

    Full Text Available The organic carbon and soils of the world comprise bulk of the terrestrial carbon and serve as amajorsink and source of atmospheric carbon. Increasing atmospheric concentrations of green house gases may be mitigated by increasing carbon sequestration in vegetation and soil. The study attempted to estimate biomass production and carbon sequestration potential of different plantation ecosystems in north western Himalaya, India. Biomass, carbon density of biomass, soil, detritus, carbon sequestration and CO2 mitigation potential were studied underdifferent plantation forest ecosystems comprising of eight different tree species viz. Quercus leucotrichophora, Pinus roxburghii, Acacia catechu, Acacia mollissima, Albizia procera, Alnus nitida, Eucalyptus tereticornis and Ulmus villosa. Above (185.57 ą 48.99 tha-1 and below ground (42.47 ą 10.38 tha-1 biomass was maximum in Ulmus villosa. The vegetation carbon density was maxium in Albizia procera (118.37 ą 1.49 tha-1 and minimum (36.50 ą 9.87 tha-1 in Acacia catechu. Soil carbon density was maximum (219.86ą 10.34 tha-1 in Alnus nitida, and minimum (170.83ą 20.60 tha-1in Pinus roxburghii. Detritus was higher in Pinus roxburghii (6.79 ą 2.0 tha-1. Carbon sequestration (7.91ą 3.4 tha-1 and CO2 mitigation potential (29.09 ą 12.78 tha-1 was maximum in Ulmus villosa. Pearson correlation matrix revealed significant positive relationship of ecosystem carbon with plantation biomass, soil carbon and CO2 mitigation potential. With the emerging threat of climate change, such assessment of forest and soil carbon inventory would allow to devise best land management and policy decisions forsustainable management of fragile hilly ecosystem. 

  16. Carbon allocation, sequestration and carbon dioxide mitigation under plantation forests of north western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Bandana Devi

    2013-05-01

    Full Text Available The organic carbon and soils of the world comprise bulk of the terrestrial carbon and serve as a major sink and source of atmospheric carbon. Increasing atmospheric concentrations of green house gases may be mitigated by increasing carbon sequestration in vegetation and soil. The study attempted to estimate biomass production and carbon sequestration potential of different plantation ecosystems in north western Himalaya, India. Biomass, carbon density of biomass, soil, detritus, carbon sequestration and CO2 mitigation potential were studied under different plantation forest ecosystems comprising of eight different tree species: Quercus leucotrichophora, Pinus roxburghii, Acacia catechu, Acacia mollissima, Albizia procera, Alnusnitida, Eucalyptus tereticornis and Ulmus villosa. Above (185.57±48.99tha-1 and below ground (42.47±10.38 tha-1 biomass was maximum in Ulmus villosa. The vegetation carbon density was maxium in Albizia procera(118.37±1.49 tha-1 and minimum (36.50±9.87 tha-1 in Acacia catechu. Soil carbon density was maximum (219.86±10.34 tha-1 in Alnus nitida, and minimum (170.83±20.60 tha-1 in Pinus roxburghii. Detritus was higher in Pinus roxburghii (6.79±2.0 tha-1. Carbon sequestration (7.91±3.4 tha-1 and CO2 mitigation potential (29.09±12.78 tha-1 was maximum in Ulmus villosa. Pearson correlation matrix revealed significant positive relationship of ecosystem carbon with plantation biomass, soil carbon and CO2 mitigation potential. With the emerging threat of climate change, such assessment of forest and soil carbon inventory would allow to devise best land management and policy decisions for sustainable management of fragile hilly ecosystem.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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...

  2. Pattern and control of biomass allocation across global forest ecosystems.

    Science.gov (United States)

    Jiang, Yongtao; Wang, Limei

    2017-07-01

    The underground part of a tree is an important carbon sink in forest ecosystems. Understanding biomass allocation between the below- and aboveground parts ( root:shoot ratios ) is necessary for estimation of the underground biomass and carbon pool. Nevertheless, large-scale biomass allocation patterns and their control mechanisms are not well identified. In this study, a large database of global forests at the community level was compiled to investigate the root:shoot ratios and their responses to environmental factors. The results indicated that both the aboveground biomass ( AGB ) and belowground biomass ( BGB ) of the forests in China (medians 73.0 Mg/ha and 17.0 Mg/ha, respectively) were lower than those worldwide (medians 120.3 Mg/ha and 27.7 Mg/ha, respectively). The root:shoot ratios of the forests in China (median = 0.23), however, were not significantly different from other forests worldwide (median = 0.24). In general, the allocation of biomass between the belowground and aboveground parts was determined mainly by the inherent allometry of the plant but also by environmental factors. In this study, most correlations between root:shoot ratios and environmental factors (development parameter, climate, altitude, and soil) were weak but significant ( p  BGB based on AGB across the entire database.

  3. 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)

  4. 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.

  5. 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.

  6. 13C incorporation into signature fatty acids as an assay for carbon allocation in arbuscular mycorrhiza.

    Science.gov (United States)

    Olsson, Pål Axel; van Aarle, Ingrid M; Gavito, Mayra E; Bengtson, Per; Bengtsson, Göran

    2005-05-01

    The ubiquitous arbuscular mycorrhizal fungi consume significant amounts of plant assimilated C, but this C flow has been difficult to quantify. The neutral lipid fatty acid 16:1omega5 is a quantitative signature for most arbuscular mycorrhizal fungi in roots and soil. We measured carbon transfer from four plant species to the arbuscular mycorrhizal fungus Glomus intraradices by estimating (13)C enrichment of 16:1omega5 and compared it with (13)C enrichment of total root and mycelial C. Carbon allocation to mycelia was detected within 1 day in monoxenic arbuscular mycorrhizal root cultures labeled with [(13)C]glucose. The (13)C enrichment of neutral lipid fatty acid 16:1omega5 extracted from roots increased from 0.14% 1 day after labeling to 2.2% 7 days after labeling. The colonized roots usually were more enriched for (13)C in the arbuscular mycorrhizal fungal neutral lipid fatty acid 16:1omega5 than for the root specific neutral lipid fatty acid 18:2omega6,9. We labeled plant assimilates by using (13)CO(2) in whole-plant experiments. The extraradical mycelium often was more enriched for (13)C than was the intraradical mycelium, suggesting rapid translocation of carbon to and more active growth by the extraradical mycelium. Since there was a good correlation between (13)C enrichment in neutral lipid fatty acid 16:1omega5 and total (13)C in extraradical mycelia in different systems (r(2) = 0.94), we propose that the total amount of labeled C in intraradical and extraradical mycelium can be calculated from the (13)C enrichment of 16:1omega5. The method described enables evaluation of C flow from plants to arbuscular mycorrhizal fungi to be made without extraction, purification and identification of fungal mycelia.

  7. Belowground herbivory and plant defenses

    NARCIS (Netherlands)

    Van Dam, N.M.

    2009-01-01

    Belowground-feeding herbivores may be very destructive to plants. Roots are known to produce various defense compounds to protect themselves against these herbivores, both with direct and indirect—inducible—defense compounds. Recent literature reviews reveal no overall pattern for root-shoot defense

  8. 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.

  9. Biomass and its allocation in relation to temperature, precipitation, and soil nutrients in Inner Mongolia grasslands, China.

    Science.gov (United States)

    Kang, Muyi; Dai, Cheng; Ji, Wenyao; Jiang, Yuan; Yuan, Zhiyou; Chen, Han Y H

    2013-01-01

    Understanding and predicting ecosystem functioning such as biomass accumulation requires an accurate assessment of large-scale patterns of biomass distribution and partitioning in relation to climatic and soil environments. We sampled above- and belowground biomass from 26 sites spanning 1500 km in Inner Mongolian grasslands, compared the difference in aboveground, belowground biomass and below-aboveground biomass ratio (AGB, BGB, and B/A, respectively) among meadow steppe, typical steppe, and desert steppe types. The relationships between AGB, BGB, B/A and climatic and soil environments were then examined. We found that AGB and BGB differed significantly among three types of grasslands while B/A did not differ. Structural equation model analyses indicated that mean annual precipitation was the strongest positive driver for AGB and BGB. AGB was also positively associated with soil organic carbon, whereas B/A was positively associated with total soil nitrogen. These results indicated that precipitation positively influence plant production in Inner Mongolian grasslands. Contrary to the prediction from the optimal partitioning hypothesis, biomass allocation to belowground increased with soil total nitrogen, suggesting that more productive sites may increase belowground allocation as an adaptive strategy to potentially high fire frequencies.

  10. Biomass and its allocation in relation to temperature, precipitation, and soil nutrients in Inner Mongolia grasslands, China.

    Directory of Open Access Journals (Sweden)

    Muyi Kang

    Full Text Available AIM: Understanding and predicting ecosystem functioning such as biomass accumulation requires an accurate assessment of large-scale patterns of biomass distribution and partitioning in relation to climatic and soil environments. METHODS: We sampled above- and belowground biomass from 26 sites spanning 1500 km in Inner Mongolian grasslands, compared the difference in aboveground, belowground biomass and below-aboveground biomass ratio (AGB, BGB, and B/A, respectively among meadow steppe, typical steppe, and desert steppe types. The relationships between AGB, BGB, B/A and climatic and soil environments were then examined. RESULTS: We found that AGB and BGB differed significantly among three types of grasslands while B/A did not differ. Structural equation model analyses indicated that mean annual precipitation was the strongest positive driver for AGB and BGB. AGB was also positively associated with soil organic carbon, whereas B/A was positively associated with total soil nitrogen. CONCLUSIONS: These results indicated that precipitation positively influence plant production in Inner Mongolian grasslands. Contrary to the prediction from the optimal partitioning hypothesis, biomass allocation to belowground increased with soil total nitrogen, suggesting that more productive sites may increase belowground allocation as an adaptive strategy to potentially high fire frequencies.

  11. Modelling C allocation in response to nutrient availability

    Science.gov (United States)

    Stocker, Benjamin; Prentice, Colin

    2015-04-01

    Carbon (C) allocation in ecosystems is a key variable of the global terrestrial C cycle. While photosynthesis governs the amount of C that enters ecosystems, its subsequent allocation to compartments with different life times determines its over-all residence time and variations in allocation patterns drive changes in ecosystem C balance and its response to environmental change. A better understanding of the controls on allocation is thus key to improving global vegetation models that commonly rely on using fixed partitioning factors. Observational data suggests variations of ecosystem structure and functioning along large-scale gradients of resource availability. Below-ground C allocation, inferred as gross primary production minus above-ground biomass production increases along gradients of decreasing nutrient availability. This is not only due to more root growth, but also due to enhanced production of exudates and stimulation of root symbionts and has been interpreted to reflect optimal plant allocation decisions under a varying soil fertility status. Here, we propose a model that accounts for trade-offs between (i) growth in above-ground and (ii) below-ground plant compartments, (iii) exudation to the rhizosphere and root symbionts and (iv) temporary storage in non-structural pools. By postulating the maximization of long-term growth under a given (seasonal regime) of soil nitrogen (N) availability, we attempt to reproduce observed large-scale gradients. The model is formulated based on a C cost for different N uptake decisions, where the cost is a function of N availability, root mass, and soil temperature (for biological N fixation). On a daily time scale, ecosystem N uptake may be realized by C exudation to the rhizosphere and/or symbiotic fixation of atmospheric N2. On an annual time scale, allocation to roots versus leaves is adjusted to soil inorganic N availability and modeled to yield maximum total growth. Exudation versus temporary storage of C is

  12. 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.

  13. 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.

  14. Effects of ozone and acidic deposition on carbon allocation and mycorrhizal colonization of Pinus taeda L. seedlings

    Science.gov (United States)

    M.B. Adams; E.G. O' Neill

    1991-01-01

    Patterns of carbon allocation and mycorrhizal colonization were examined in loblolly pine seedlings from two half-sib families exposed to three ozone treatments (charcoal-filtered air, ambient air + 80 ppb 03 , and ambient air + 160 ppb 03) and three rain pH levels (5.2, 4.5, and 3.3) for 12 weeks in open-topped chambers in...

  15. Belowground carbon sources and fine root turnover times using 13C tracer at the conclusion of a long-term FACE experiment

    Science.gov (United States)

    Lynch, D. J.; Matamala, R.; Norby, R.; Iversen, C.; Gonzalez-Meler, M. A.

    2011-12-01

    Estimates of carbon budgets require accurate approximations of fine root production and turnover. Current published estimates of root carbon turnover vary more than five-fold, with large differences between isotope-derived estimates, minirhizotron studies or other approaches. Variations in residence times between root structural and reserve C, root orders and new photosynthate to support root function have been shown independently, but have not been yet reconciled in a single study. Taking advantage of the conclusion of the long-term FACE experiment at Oak Ridge National Laboratory, we track the whole ecosystem isotope relaxation in fine root pools (Liquidambar styraciflua, and to identify carbon sources for new root growth and for energy metabolism. We sampled intact and in-growth root cores at regular (minimum time was monthly) intervals in 2010 and at several intervals in 2011. Additionally, fine roots and soils were incubated from three sampling periods each from 2010 and 2011 for measurement of the isotopic signature of respired CO2. Our results show a residence time of carbon in fine roots consistent with previous stable isotope reports for this species, with about 20% of structural C replaced after one full growing season. In contrast, all new root growth (evidenced from in-growth cores) was supported by new photosynthate, except for some storage carbon used very early in the growing season. Carbon used for energy metabolism in roots exclusively originated from new photosynthate during all measurement periods. Our results confirm heterogeneity of C pools in existing and new roots and the relatively long residence time of structural C in existing fine roots.

  16. Influence of pCO2 on carbon allocation in nodulated Medicago sativa L.

    Science.gov (United States)

    Pereyra, Gabriela; Hartmann, Henrik; Ziegler, Waldemar; Michalzik, Beate; Gonzalez-Meler, Miquel; Trumbore, Susan

    2016-04-01

    Atmospheric CO2 concentrations (pCO_2) have been related to changes in plant carbon (C) availability and photosynthetic capacity, yet there is no clear consensus as to the effect of pCO2 on the plant C balance and on nitrogen fixation in symbiotic systems. We investigated how different pCO2 (Pleistocene: 170 ppm, ambient: 400 ppm and projected future: 700 ppm) influence C allocation in nodulated Medicago sativa L. We labeled 17 week old plants with depleted 13C (-34.7±1.2‰) and traced the label over a 9-day period, to assess the redistribution of newly assimilated C across different sinks, including nodules. We analyzed N concentrations in plant tissues and found no significant differences in leaves and roots across treatments. However, growth and C fixation rates increased with pCO_2, and differences were greatest between 170 ppm and 700 ppm. Across pCO2 treatments we observed a 13C-enrichment in roots compared to leaves. We further observed the highest 13C depletion of non-structural carbohydrates (NSCs) and respired CO2 in tissues of plants grown at 700 ppm, especially in leaves and nodules. Our preliminary results suggest that sink organs like roots and nodules are fed with newly-assimilated NSCs from leaves to support respiration, and especially in 170 ppm plants represented a major respiratory loss of newly assimilated C (≈ 35{%} of the total plant respiration). Our results suggest that although plant metabolic processes like photosynthesis and respiration are affected by changes in pCO_2, nitrogen acquisition in such a symbiotic system is not.

  17. 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...

  18. 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...

  19. Efficiency Allocation of Provincial Carbon Reduction Target in China’s “13·5” Period: Based on Zero-Sum-Gains SBM Model

    Directory of Open Access Journals (Sweden)

    Wen Guo

    2017-01-01

    Full Text Available Firstly, we introduce the “Zero Sum Gains” game theory into the SBM (Slacks-based Measure model, and establish the ZSG-SBM model. Then, set up 4 development scenarios for the China’s economic system in “13·5” (The Chinese government formulates a Five-Year Planning for national economic and social development every five years, “13·5” means 2016 to 2020. period through two dimensions as economic growth and energy consumption structure, and make the efficient allocation in provincial level of carbon reduction target by using the above ZSG-SBM model based on the China’s overall carbon reduction constraint (18% which is set in “13·5” planning. Finally, we analyze the provincial development path of low-carbon economy by comparing the economic development status with the allocated result of carbon reduction target. Results show that: After the ZSG-SBM model being applied to the efficiency allocation of carbon emission, the input and output indicators of the 30 provinces realize the effective allocation, and the carbon emission efficiency reaches the efficiency frontier. The equity-oriented administrative allocation scheme of government will bring about efficiency loss in a certain degree, and the efficiency allocation scheme, based on the ZSG-SBM model, fits better with the long-term development requirement of low-carbon economy. On the basis of carbon intensity constraint, the re-constraint of energy intensity will force the provinces to optimize their energy consumption structure, thereby enhancing the overall carbon emission efficiency of China. Sixteen provinces’ allocation results of carbon reduction target are above China’s average (18% in “13·5” period, all the provinces should select appropriate development path of low-carbon economy according to the status of their resource endowment, economic level, industrial structure and energy consumption structure.

  20. [Variation of below-ground carbon sequestration under long term cultivation and grazing in the typical steppe of Nei Monggol in North China].

    Science.gov (United States)

    Yan, Yu-Chun; Tang, Hai-Ping; Chang, Rui-Ying; Liu, Liang

    2008-05-01

    Human activities have changed the earth surface mostly, which caused many environment issues now. We aimed to detect the process that human activities exert on ecosystem by investigating and analyzing the changes of plant community, especially underground soil and root carbon sequestration under long-term cultivation and grazing in typical steppe area of Nei Monggol, North China. The carbon sequestration on the root and soil in three plots of typical steppe area: 26-year exclosure grassland (E26), continuous grazing grassland (LG) and 35-year cultivated tillage (LC) were measured. The carbon storage in the layer of 0-40 cm showed a trend that E26 (7 307.59 g x m(-2) and 950.32 g x m(-2)) approximately LG (7834.01 g x m(-2) and 843.43 g x m(-2)) > LC (4537.04 g x m(-2) and 277.35 g x m(-2)), occupied 88.49%, 90.28% and 94.24% of total soil-root carbon respectively. The original composition structure of plant-soil system was completely destroyed by human cultivation, and it also led to sever soil erosion as well. The sand content in soil of LC at layers 0-10 cm, 10-20 cm were increasing by 81% and 39% compared to E26. On the other hand, the root biomass of LG at 0-40 cm decreased by 71%. Cultivation resulted in significant decrease of the carbon storages in soil and root. Therefore, the present cultivation should be ceased and the optimum measurements should be taken to make the tillage restore to natural grassland condition. Continuous grazing led to the significantly changes of the above-ground vegetation characteristics such as community height, coverage and biomass. While the changes of soil organic content and root biomass was not remarkable under grazing. However, the bulk density of surface soil (0-10 cm) exhibited significant increase in LG compared to E26, which indicated that the present grazing pressure have been reaching the threshold of grassland capacity. Therefore, the present grazing pressure should be decreased properly in order to avoid more serious

  1. 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.

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

    Science.gov (United States)

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

    2011-08-01

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

  3. The variation of productivity and its allocation along a tropical elevation gradient: a whole carbon budget perspective.

    Science.gov (United States)

    Malhi, Yadvinder; Girardin, Cécile A J; Goldsmith, Gregory R; Doughty, Christopher E; Salinas, Norma; Metcalfe, Daniel B; Huaraca Huasco, Walter; Silva-Espejo, Javier E; Del Aguilla-Pasquell, Jhon; Farfán Amézquita, Filio; Aragão, Luiz E O C; Guerrieri, Rossella; Ishida, Françoise Yoko; Bahar, Nur H A; Farfan-Rios, William; Phillips, Oliver L; Meir, Patrick; Silman, Miles

    2017-05-01

    Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation. We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 3300 m elevation transect in Peru. Low growth rates at high elevations appear primarily driven by low gross primary productivity (GPP), with little shift in either carbon use efficiency (CUE) or allocation of net primary productivity (NPP) between wood, fine roots and canopy. The lack of trend in CUE implies that the proportion of photosynthate allocated to autotrophic respiration is not sensitive to temperature. Rather than a gradual linear decline in productivity, there is some limited but nonconclusive evidence of a sharp transition in NPP between submontane and montane forests, which may be caused by cloud immersion effects within the cloud forest zone. Leaf-level photosynthetic parameters do not decline with elevation, implying that nutrient limitation does not restrict photosynthesis at high elevations. Our data demonstrate the potential of whole carbon budget perspectives to provide a deeper understanding of controls on ecosystem functioning and carbon cycling. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  4. The role of soil microbes in the global carbon cycle: tracking the below-ground microbial processing of plant-derived carbon for manipulating carbon dynamics in agricultural systems.

    Science.gov (United States)

    Gougoulias, Christos; Clark, Joanna M; Shaw, Liz J

    2014-09-01

    It is well known that atmospheric concentrations of carbon dioxide (CO2) (and other greenhouse gases) have increased markedly as a result of human activity since the industrial revolution. It is perhaps less appreciated that natural and managed soils are an important source and sink for atmospheric CO2 and that, primarily as a result of the activities of soil microorganisms, there is a soil-derived respiratory flux of CO2 to the atmosphere that overshadows by tenfold the annual CO2 flux from fossil fuel emissions. Therefore small changes in the soil carbon cycle could have large impacts on atmospheric CO2 concentrations. Here we discuss the role of soil microbes in the global carbon cycle and review the main methods that have been used to identify the microorganisms responsible for the processing of plant photosynthetic carbon inputs to soil. We discuss whether application of these techniques can provide the information required to underpin the management of agro-ecosystems for carbon sequestration and increased agricultural sustainability. We conclude that, although crucial in enabling the identification of plant-derived carbon-utilising microbes, current technologies lack the high-throughput ability to quantitatively apportion carbon use by phylogentic groups and its use efficiency and destination within the microbial metabolome. It is this information that is required to inform rational manipulation of the plant-soil system to favour organisms or physiologies most important for promoting soil carbon storage in agricultural soil. © 2014 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

  5. Evaluation of allocation methods for calculation of carbon footprint of grass-based dairy production.

    Science.gov (United States)

    Rice, P; O'Brien, D; Shalloo, L; Holden, N M

    2017-11-01

    A major methodological issue for life cycle assessment, commonly used to quantify greenhouse gas emissions from livestock systems, is allocation from multifunctional processes. When a process produces more than one output, the environmental burden has to be assigned between the outputs, such as milk and meat from a dairy cow. In the absence of an objective function for choosing an allocation method, a decision must be made considering a range of factors, one of which is the availability and quality of necessary data. The objective of this study was to evaluate allocation methods to calculate the climate change impact of the economically average (€/ha) dairy farm in Ireland considering both milk and meat outputs, focusing specifically on the pedigree of the available data for each method. The methods were: economic, energy, protein, emergy, mass of liveweight, mass of carcass weight and physical causality. The data quality for each method was expressed using a pedigree score based on reliability of the source, completeness, temporal applicability, geographical alignment and technological appropriateness. Scenario analysis was used to compare the normalised impact per functional unit (FU) from the different allocation methods, between the best and worst third of farms (in economic terms, €/ha) in the national farm survey. For the average farm, the allocation factors for milk ranged from 75% (physical causality) to 89% (mass of carcass weight), which in turn resulted in an impact per FU, from 1.04 to 1.22 kg CO 2 -eq/kg (fat and protein corrected milk). Pedigree scores ranged from 6.0 to 17.1 with protein and economic allocation having the best pedigree. It was concluded that when making the choice of allocation method, the quality of the data available (pedigree) should be given greater emphasis during the decision making process because the effect of allocation on the results. A range of allocation methods could be deployed to understand the uncertainty

  6. Closing the Carbon Budget in Perennial Biofuel Crops

    Science.gov (United States)

    Kantola, I. B.; Anderson-Teixeira, K. J.; Bernacchi, C.; Hudiburg, T. W.; Masters, M. D.; DeLucia, E. H.

    2013-12-01

    At present, some 40% of corn grown in the United States, accounting for more than 26 million acres of farmland, is processed for bioethanol. Interest has arisen in converting biofuel production from corn grain ethanol to cellulosic ethanol, derived primarily from cellulose from dedicated energy crops. As many cellulosic biofuel feedstocks are perennial grasses, conversion from annual corn cropping to perennials represents a substantial change in farming practices with the potential to alter the plant-soil relationship in the Midwestern United States. Elimination of annual tillage preserves soils structure, conserving soil carbon and maintaining plant root systems. Five years of perennial grass establishment in former agricultural land in Illinois has shown a significant change in soil carbon pools and fluxes. Atmospheric carbon exchange monitoring combined with vegetation and soil sampling and respiration measurements confirm that in the first 3 years (establishment phase), perennial giant grasses Miscanthus x giganteus and Panicum virgatum rapidly increased belowground carbon allocation >400% and belowground biomass 400-750% compared to corn. Following establishment, perennial grasses maintained below- and aboveground annual biomass production, out-performing corn in both average and drought conditions. Here we offer a quantitative comparison of the carbon allocation pathways of corn and perennial biofuel crops in Midwestern landscapes, demonstrating the carbon benefits of perennial cropping through increased C allocation to root and rhizome structures. Long rotation periods in perennial grasses combined with annual carbon inputs to the soil system are expected to convert these agricultural soils from atmospheric carbon sources to carbon sinks.

  7. 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.

  8. 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)

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Cristina Armas

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  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. 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

  13. 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

  14. 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

  15. Assessment of carbon allocation and biomass production in a natural stand of the salt marsh plant Spartina anglica using C- 13

    NARCIS (Netherlands)

    Hemminga, M.A.; Huiskes, A.H.L.; Steegstra, M.; Van Soelen, J.

    1996-01-01

    The proportional allocation of photosynthetically fixed carbon to the root and shoot system of salt marsh plants is an important element in the carbon cycle of tidal salt marshes. The commonly applied field methods giving insight on this point are based on successive harvesting of biomass. These

  16. 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.

  17. Carbon Allocation into Different Fine-Root Classes of Young Abies alba Trees Is Affected More by Phenology than by Simulated Browsing.

    Science.gov (United States)

    Endrulat, Tina; Buchmann, Nina; Brunner, Ivano

    2016-01-01

    Abies alba (European silver fir) was used to investigate possible effects of simulated browsing on C allocation belowground by 13CO2 pulse-labelling at spring, summer or autumn, and by harvesting the trees at the same time point of the labelling or at a later season for biomass and for 13C-allocation into the fine-root system. Before budburst in spring, the leader shoots and 50% of all lateral shoots of half of the investigated 5-year old Abies alba saplings were clipped to simulate browsing. At harvest, different fine-root classes were separated, and starch as an important storage compartment was analysed for concentrations. The phenology had a strong effect on the allocation of the 13C-label from shoots to roots. In spring, shoots did not supply the fine-roots with high amounts of the 13C-label, because the fine-roots contained less than 1% of the applied 13C. In summer and autumn, however, shoots allocated relatively high amounts of the 13C-label to the fine roots. The incorporation of the 13C-label as structural C or as starch into the roots is strongly dependent on the root type and the root diameter. In newly formed fine roots, 3-5% of the applied 13C was incorporated, whereas 1-3% in the ≤0.5 mm root class and 1-1.5% in the >0.5-1.0 mm root class were recorded. Highest 13C-enrichment in the starch was recorded in the newly formed fine roots in autumn. The clipping treatment had a significant positive effect on the amount of allocated 13C-label to the fine roots after the spring labelling, with high relative 13C-contents observed in the ≤0.5 mm and the >0.5-1.0 mm fine-root classes of clipped trees. No effects of the clipping were observed after summer and autumn labelling in the 13C-allocation patterns. Overall, our data imply that the season of C assimilation and, thus, the phenology of trees is the main determinant of the C allocation from shoots to roots and is clearly more important than browsing.

  18. Factors modulating cottongrass seedling growth stimulation to enhanced nitrogen and carbon dioxide: compensatory tradeoffs in leaf dynamics and allocation to meet potassium-limited growth.

    Science.gov (United States)

    Siegenthaler, Andy; Buttler, Alexandre; Grosvernier, Philippe; Gobat, Jean-Michel; Nilsson, Mats B; Mitchell, Edward A D

    2013-02-01

    Eriophorum vaginatum is a characteristic species of northern peatlands and a keystone plant for cutover bog restoration. Understanding the factors affecting E. vaginatum seedling establishment (i.e. growth dynamics and allocation) under global change has practical implications for the management of abandoned mined bogs and restoration of their C-sequestration function. We studied the responses of leaf dynamics, above- and belowground biomass production of establishing seedlings to elevated CO(2) and N. We hypothesised that nutrient factors such as limitation shifts or dilutions would modulate growth stimulation. Elevated CO(2) did not affect biomass, but increased the number of young leaves in spring (+400 %), and the plant vitality (i.e. number of green leaves/total number of leaves) (+3 %), both of which were negatively correlated to [K(+)] in surface porewater, suggesting a K-limited production of young leaves. Nutrient ratios in green leaves indicated either N and K co-limitation or K limitation. N addition enhanced the number of tillers (+38 %), green leaves (+18 %), aboveground and belowground biomass (+99, +61 %), leaf mass-to-length ratio (+28 %), and reduced the leaf turnover (-32 %). N addition enhanced N availability and decreased [K(+)] in spring surface porewater. Increased tiller and leaf production in July were associated with a doubling in [K(+)] in surface porewater suggesting that under enhanced N production is K driven. Both experiments illustrate the importance of tradeoffs in E. vaginatum growth between: (1) producing tillers and generating new leaves, (2) maintaining adult leaves and initiating new ones, and (3) investing in basal parts (corms) for storage or in root growth for greater K uptake. The K concentration in surface porewater is thus the single most important factor controlling the growth of E. vaginatum seedlings in the regeneration of selected cutover bogs.

  19. Above- and Below-ground Biomass, Net Ecosystem Carbon Exchange, and Soil Respiration in a Poplar Populus deltoides Bartr.) stand : Changes after 3 years of Growth under Elevated CO2

    Science.gov (United States)

    Barron-Gafford, G. A.; Grieve, K.; Bil, K.; Kudeyarov, V.; Handley, L.; Murthy, R.

    2003-12-01

    Stands of cottonwood (Populus deltoides Bartr.) trees were grown as a coppiced system under ambient (40 Pa), twice ambient (80 Pa), and three times ambient (120 Pa) partial pressure CO2 for the past three years in the Intensively-managed Forest Mesocosm (IFM) of the Biosphere 2 Center. Over three years Net Ecosystem CO2 exchange (NECE) was measured continuously and in the third year, nine whole trees were harvested from each CO2 treatment over the growing season. Both above- and below-ground parameters were measured. Three years of growth under elevated CO2 showed the expected stimulation in foliar biomass (8.7, 11.9, and 13.1 kg for the 40, 80, and 120 Pa treatments, respectively). Rates of NECE also followed an expected increase with elevated atmospheric CO2 concentrations, with maximum CO2 uptake rates reaching 10.5, 15.6, and 19.6 μ moles m-2 s-1 in the 40, 80, and 120 Pa treatments, respectively. However, above ground woody biomass and root biomass were not much stimulated beyond 80 Pa CO2. Wood/foliage and above/below ground biomass ratios reflect this decline. Under conditions of non-limiting nutrients and water, we found consistent increases in the above/below ground biomass ratio and wood to foliage biomass ratios in the 80 compared to the 40 Pa pCO2. Woody biomass production and the above/below ground biomass ratio were lower under the 120 Pa than any other treatment. Although biomass production did not change appreciably between 80 and 120 Pa CO2 treatments, both substrate induced and in-situ soil respiration values are also significantly higher in the 120Pa treatment, though no differences were present prior to CO2 treatments (Murthy et al. 2003). The unique closed-system operation of the IFM allowed for measures of soil CO2 efflux to be measured at both the soil collar and stand scales using a box model that takes into account all inputs and outputs from the stand. In-situ soil respiration rates increased significantly with increased atmospheric CO2

  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. 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....

  2. 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).

  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. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes.

    Science.gov (United States)

    McCormack, M Luke; Dickie, Ian A; Eissenstat, David M; Fahey, Timothy J; Fernandez, Christopher W; Guo, Dali; Helmisaari, Heljä-Sisko; Hobbie, Erik A; Iversen, Colleen M; Jackson, Robert B; Leppälammi-Kujansuu, Jaana; Norby, Richard J; Phillips, Richard P; Pregitzer, Kurt S; Pritchard, Seth G; Rewald, Boris; Zadworny, Marcin

    2015-08-01

    Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally - a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  5. Two Decades of International Climate Negotiations - Carbon Budget Allocation Approach to Re-shaping Developing Country Strategies

    Directory of Open Access Journals (Sweden)

    Sudhakar Yedla

    2014-09-01

    Full Text Available Climate negotiations have been going on for the last two decades and the awareness for impacts of climate change has improved substantially. However, the trends of global CO2 emissions did not reveal any encouraging signs, with developing countries emitting even more CO2 and industrialized nations showing no signs of reducing emissions to below their 1990 levels. In order to meet the ambitious targets set by the Stern report for the next two decades, it is important to find new and path-breaking approaches to climate change. This paper attempts to analyze the use of carbon/development space historically, at present and in the future with a focus on equity. Trends analysis focuses on the last two decades (Post Rio and the carbon budget based analysis considers a period of 1850-2050. Industrialized countries are found to have significantly overshot their budgeted allocation for the last 160 years. Both the developing and industrialized countries are overshooting the present budget estimates based on world per capita budget for the next forty years and proportional to the population of each country. It is important for the industrialized countries to bring down their emissions to meet their carbon budgets while the developing countries use their development space as a guideline for their development path. Furthermore, this paper presents aggressive and regressive scenarios for the industrialized countries to compensate for the climate debt they have created.

  6. THE EVOLUTION OF CARBON ALLOCATION TO PLANT SECONDARY METABOLITES: A GENETIC ANALYSIS OF COST IN DIPLACUS AURANTIACUS.

    Science.gov (United States)

    Han, Kaiping; Lincoln, David E

    1994-10-01

    Diplacus aurantiacus contains large amounts of a leaf phenolic resin, an important deterrent to a leaf-eating caterpillar, Euphydryas chalcedona. The resin can also retard water loss during drought. Furthermore, the leaf resin content differs among plants and populations. This study investigates the existence of heritable variation (h 2 ) in resin production and tests for a genetic correlation (r G ) between carbon allocation to secondary metabolites and growth rate, as well as with three other vegetative traits. Nine dam and 10 sire plants were chosen randomly at a field site and used to generate 78 full-sib families (19 half-sib families) by crossing all males to all females in a factorial design. Heritability was estimated in two ways, and genetic correlations were estimated by three methods. We found: (1) the heritability of resin production estimated by the regression of offspring on sires was significantly greater than zero (hs2=0.32, PEvolution.

  7. 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

  8. Nutrient Effects on Belowground Organic Matter in a Minerogenic Salt Marsh, North Inlet, SC

    Science.gov (United States)

    Belowground structure and carbon dioxide emission rates were examined in minerogenic marshes of the North Inlet estuary, a system dominated by depositional processes and typical of the southeastern USA. Three areas were sampled: a long-term nutrient enrichment experiment (Goat Is...

  9. 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

  10. 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.

  11. Size-dependent mortality in a Neotropical savanna tree: the role of height-related adjustments in hydraulic architecture and carbon allocation

    Science.gov (United States)

    Yong-Jiang Zhang; Frederick C. Meinzer; Guang-You Hao; Fabian G. Scholz; Sandra J. Bucci; Frederico S.C. Takahashi; Randol Villalobos-Vega; Juan P. Giraldo; Kun-Fang Cao; William A. Hoffmann; Guillermo Goldstein

    2009-01-01

    Size-related changes in hydraulic architecture, carbon allocation, and gas exchange of Sclerolobium paniculatum (Leguminosae), a dominant tree species in Neotropical savannas of central Brazil (Cerrado), were investigated to assess their potential role in the dieback of tall individuals. Trees greater than ~6 m tall exhibited more branch damage,...

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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...

  17. 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.

  18. 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

    Directory of Open Access Journals (Sweden)

    Jessica L. O’Connell

    2015-12-01

    Full Text Available 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.

  19. Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants.

    Science.gov (United States)

    Fellbaum, Carl R; Mensah, Jerry A; Cloos, Adam J; Strahan, Gary E; Pfeffer, Philip E; Kiers, E Toby; Bücking, Heike

    2014-07-01

    Common mycorrhizal networks (CMNs) of arbuscular mycorrhizal (AM) fungi in the soil simultaneously provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled are unknown. Using radioactive and stable isotopes, we followed the transport of phosphorus (P) and nitrogen (N) in the CMNs of two fungal species to plants that differed in their carbon (C) source strength, and correlated the transport to the expression of mycorrhiza-inducible plant P (MtPt4) and ammonium (1723.m00046) transporters in mycorrhizal roots. AM fungi discriminated between host plants that shared a CMN and preferentially allocated nutrients to high-quality (nonshaded) hosts. However, the fungus also supplied low-quality (shaded) hosts with nutrients and maintained a high colonization rate in these plants. Fungal P transport was correlated to the expression of MtPt4. The expression of the putative ammonium transporter 1723.m00046 was dependent on the fungal nutrient supply and was induced when the CMN had access to N. Biological market theory has emerged as a tool with which the strategic investment of competing partners in trading networks can be studied. Our work demonstrates how fungal partners are able to retain bargaining power, despite being obligately dependent on their hosts. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  20. Legacy effects of aboveground–belowground interactions

    NARCIS (Netherlands)

    Kostenko, O.; Van de Voorde, T.F.J.; Mulder, P.P.J.; Van der Putten, W.H.; Bezemer, T.M.

    2012-01-01

    Root herbivory can greatly affect the performance of aboveground insects via changes in plant chemistry. These interactions have been studied extensively in experiments where aboveground and belowground insects were feeding on the same plant. However, little is known about how aboveground and

  1. Legacy effects of aboveground-belowground interactions

    NARCIS (Netherlands)

    Kostenko, O.; Voorde, van de T.F.J.; Mulder, P.P.J.; Putten, van der W.H.; Bezemer, T.M.

    2012-01-01

    Root herbivory can greatly affect the performance of aboveground insects via changes in plant chemistry. These interactions have been studied extensively in experiments where aboveground and belowground insects were feeding on the same plant. However, little is known about how aboveground and

  2. 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.

  3. A whole-plant perspective reveals unexpected impacts of above- and belowground herbivores on plant growth and defense.

    Science.gov (United States)

    Mundim, Fabiane M; Alborn, Hans T; Vieira-Neto, Ernane H M; Bruna, Emilio M

    2017-01-01

    Trade-offs between plant growth and defense are central to theoretical frameworks used to study the ecology and evolution of plant defense against herbivores. However, these frameworks, as well as the experiments designed to test them, rarely include belowground herbivores. We experimentally challenged seedlings of the tropical shrub Solanum lycocarpum (Solanaceae) with either aboveground foliar herbivores (Spodoptera caterpillars) or belowground root herbivores (the nematode Meloidogyne incognita) and measured the resulting changes in plant growth rates, biomass allocation, and the concentration of defensive terpenoids in roots and leaves. We found that plants that suffered aboveground herbivory responded with aboveground growth but belowground defense. Similarly, belowground herbivory resulted in root growth but elevated defenses of leaves. These results underscore the importance of belowground plant-herbivore interactions, and suggest that, in contrast to theoretical predictions, plants can simultaneously invest in both growth and defense. Finally, they emphasize the need for a "whole-plant" perspective in theoretical and empirical evaluations of plant-herbivore interactions. © 2016 by the Ecological Society of America.

  4. 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

  5. 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

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

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    Full Text Available 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.

  7. Genome-enabled Discovery of Carbon Sequestration Genes

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Tschaplinski, Timothy J [ORNL; Kalluri, Udaya C [ORNL; Yin, Tongming [ORNL; Yang, Xiaohan [ORNL; Zhang, Xinye [ORNL; Engle, Nancy L [ORNL; Ranjan, Priya [ORNL; Basu, Manojit M [ORNL; Gunter, Lee E [ORNL; Jawdy, Sara [ORNL; Martin, Madhavi Z [ORNL; Campbell, Alina S [ORNL; DiFazio, Stephen P [ORNL; Davis, John M [University of Florida; Hinchee, Maud [ORNL; Pinnacchio, Christa [U.S. Department of Energy, Joint Genome Institute; Meilan, R [Purdue University; Busov, V. [Michigan Technological University; Strauss, S [Oregon State University

    2009-01-01

    The fate of carbon below ground is likely to be a major factor determining the success of carbon sequestration strategies involving plants. Despite their importance, molecular processes controlling belowground C allocation and partitioning are poorly understood. This project is leveraging the Populus trichocarpa genome sequence to discover genes important to C sequestration in plants and soils. The focus is on the identification of genes that provide key control points for the flow and chemical transformations of carbon in roots, concentrating on genes that control the synthesis of chemical forms of carbon that result in slower turnover rates of soil organic matter (i.e., increased recalcitrance). We propose to enhance carbon allocation and partitioning to roots by 1) modifying the auxin signaling pathway, and the invertase family, which controls sucrose metabolism, and by 2) increasing root proliferation through transgenesis with genes known to control fine root proliferation (e.g., ANT), 3) increasing the production of recalcitrant C metabolites by identifying genes controlling secondary C metabolism by a major mQTL-based gene discovery effort, and 4) increasing aboveground productivity by enhancing drought tolerance to achieve maximum C sequestration. This broad, integrated approach is aimed at ultimately enhancing root biomass as well as root detritus longevity, providing the best prospects for significant enhancement of belowground C sequestration.

  8. Molecular insights into how a deficiency of amylose affects carbon allocation – carbohydrate and oil analyses and gene expression profiling in the seeds of a rice waxy mutant

    Directory of Open Access Journals (Sweden)

    Zhang Ming-Zhou

    2012-12-01

    Full Text Available Abstract Background Understanding carbon partitioning in cereal seeds is of critical importance to develop cereal crops with enhanced starch yields for food security and for producing specified end-products high in amylose, β-glucan, or fructan, such as functional foods or oils for biofuel applications. Waxy mutants of cereals have a high content of amylopectin and have been well characterized. However, the allocation of carbon to other components, such as β-glucan and oils, and the regulation of the altered carbon distribution to amylopectin in a waxy mutant are poorly understood. In this study, we used a rice mutant, GM077, with a low content of amylose to gain molecular insight into how a deficiency of amylose affects carbon allocation to other end products and to amylopectin. We used carbohydrate analysis, subtractive cDNA libraries, and qPCR to identify candidate genes potentially responsible for the changes in carbon allocation in GM077 seeds. Results Carbohydrate analysis indicated that the content of amylose in GM077 seeds was significantly reduced, while that of amylopectin significantly rose as compared to the wild type BP034. The content of glucose, sucrose, total starch, cell-wall polysaccharides and oil were only slightly affected in the mutant as compared to the wild type. Suppression subtractive hybridization (SSH experiments generated 116 unigenes in the mutant on the wild-type background. Among the 116 unigenes, three, AGP, ISA1 and SUSIBA2-like, were found to be directly involved in amylopectin synthesis, indicating their possible roles in redirecting carbon flux from amylose to amylopectin. A bioinformatics analysis of the putative SUSIBA2-like binding elements in the promoter regions of the upregulated genes indicated that the SUSIBA2-like transcription factor may be instrumental in promoting the carbon reallocation from amylose to amylopectin. Conclusion Analyses of carbohydrate and oil fractions and gene expression

  9. 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

  10. 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

  11. Competition for light and water increases tree carbon allocation to fine roots and leaves in a next-generation dynamic vegetation model

    Science.gov (United States)

    Lichstein, J. W.; Zhang, T.; Weng, E.; Farrior, C.; Dybzinski, R.; Birdsey, R.; Pacala, S. W.

    2015-12-01

    The response of the terrestrial carbon (C) cycle to climate change is a key uncertainty in land models. An important component of this uncertainty concerns plant functional diversity, which is typically represented in land models by ~10 functional types (PFTs) with fixed traits. However, few land models include the individual-level competitive mechanisms that largely determine how plant functional traits are distributed in time and space in real ecosystems. We have developed a new land model that represents height-structured competition for light with a simple canopy space-filling algorithm, the perfect plasticity approximation (PPA). The new land model, LM3-PPA, allows for an arbitrary number of PFTs (or 'species') whose spatial-temporal distributions are determined by the outcome of competition for light and water. We performed experiments with a modified version of LM3-PPA in 10 eastern U.S. grid cells and across simulated precipitation gradients to determine how competition for light and water affects tree C allocation to leaves, fine roots, and wood across climate gradients and in response to episodic drought. We studied the performance of 16 allocational types ('species') in monoculture and in competition with each other to determine the competitively-optimal, NPP-maximizing, and biomass-maximizing C allocation strategy under different environmental conditions. Under chronically moist conditions, competitively-optimal, NPP-maximizing, and biomass-maximizing trees all had similar C allocation. However, under chronically dry conditions, competitively-optimal trees allocated more C to both fine roots and leaves, and less C to wood, compared to NPP- or biomass-maximizing strategies. When subject to episodic drought, the most drought-tolerant allocational strategies had relatively low allocation to leaves (and thus low leaf area and low water demand). Thus, the "over-investment" in leaves that results from resource competition increases the vulnerability of

  12. 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

  13. Nutrient Effects on Belowground Organic Matter in a ...

    Science.gov (United States)

    Belowground structure and carbon dioxide emission rates were examined in minerogenic marshes of the North Inlet estuary, a system dominated by depositional processes and typical of the southeastern USA. Three areas were sampled: a long-term nutrient enrichment experiment (Goat Island); a fringing marsh that only receives drainage from an entirely forested watershed (upper Crab Haul Creek); and three locations along a creek basin that receives drainage from a residential and golf course development situated at its headwaters (Debidue Creek). Responses to fertilization at Goat Island were an increase in soil organic matter, an increase in number of rhizomes, enlarged rhizome diameters, decreased fine root mass, and increased carbon dioxide emission rates. At the Crab Haul Creek, the greatest abundances of coarse roots and rhizomes were observed in the high marsh compared to the low marsh and creekbank. The upper and mid Debidue Creek, which may be influenced by nutrient inputs associated with land development, had significantly fewer rhizomes compared to the mouth, which was dominated by exchange with bay waters. Carbon dioxide emission rates at the fertilized Goat Island plots were similar in magnitude to the upper Debidue Creek and significantly greater than the Goat Island control plots and the Crab Haul Creek. Inputs of sediment and particulates in marshes dominated by depositional processes such as the North Inlet may buffer the system from adverse effects of

  14. Above- and belowground insect herbivores differentially affect soil nematode communities in species-rich plant communities

    NARCIS (Netherlands)

    Deyn, de G.B.; Ruijven, van J.; Raaijmakers, C.E.; Ruiter, de P.C.; Putten, van der W.H.

    2007-01-01

    Interactions between above- and belowground invertebrate herbivores alter plant diversity, however, little is known on how these effects may influence higher trophic level organisms belowground. Here we explore whether above- and belowground invertebrate herbivores which alter plant community

  15. Allometric equations for estimating belowground biomass ofAndrostachys johnsoniiPrain.

    Science.gov (United States)

    Magalhães, Tarquinio Mateus

    2015-12-01

    The belowground component of the trees is still poorly known because it needs labour- and time-intensive in situ measurements. However, belowground biomass (BGB) constitutes a significant share of the total forest biomass. I analysed the BGB allocation patterns, fitted models for estimating root components and root system biomasses, and called attention for its possible use in predicting anchoring functions of the different root components. More than half and almost one third of BGB is allocated to the lateral roots and to the root collar, respectively. More than 80% of the BGB is found at a depth range of 9.6-61.2 cm. As the tree size increased, the proportion of BGB allocated to taproots decreased and that allocated to lateral roots increased. All independent models performed almost equally, with the predictors explaining, on average, 98% of the variation in the BGB. It was hypothesised that BGB allocation patterns are a response of the anchoring functions of the tap and lateral roots and therefore, root component biomass models can be used as a methodology to predict anchoring functions of the different root components. Based on the fact that all models performed almost equally, the models using either diameter at breast height (DBH) exclusively as a predictor should be preferred, as tree height is difficult to measure. Models using the root collar diameter (RCD) only should be preferred when the tree is found cut down, as sometimes the RCD is affected by root buttress. Given the large sample size, the validation results, and the coverage of a wide geographical, soil and climatic range, the models fitted can be applied in all A. johnsonii stands in Mozambique.

  16. 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

    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...

  17. Linking aboveground and belowground interactions via induced plant defenses

    NARCIS (Netherlands)

    Bezemer, T.M.; Dam, van N.M.

    2005-01-01

    Plants have a variety of chemical defenses that often increase in concentration following attack by herbivores. Such induced plant responses can occur aboveground, in the leaves, and also belowground in the roots. We show here that belowground organisms can also induce defense responses aboveground

  18. Allometric scaling relationship between above- and below-ground biomass within and across five woody seedlings.

    Science.gov (United States)

    Cheng, Dongliang; Ma, Yuzhu; Zhong, Quanling; Xu, Weifeng

    2014-10-01

    Allometric biomass allocation theory predicts that leaf biomass (M L ) scaled isometrically with stem (M S ) and root (M R ) biomass, and thus above-ground biomass (leaf and stem) (M A ) and root (M R ) scaled nearly isometrically with below-ground biomass (root) for tree seedlings across a wide diversity of taxa. Furthermore, prior studies also imply that scaling constant should vary with species. However, litter is known about whether such invariant isometric scaling exponents hold for intraspecific biomass allocation, and how variation in scaling constants influences the interspecific scaling relationship between above- and below-ground biomass. Biomass data of seedlings from five evergreen species were examined to test scaling relationships among biomass components across and within species. Model Type II regression was used to compare the numerical values of scaling exponents and constants among leaf, stem, root, and above- to below-ground biomass. The results indicated that M L and M S scaled in an isometric or a nearly isometric manner with M R , as well as M A to M R for five woody species. Significant variation was observed in the Y-intercepts of the biomass scaling curves, resulting in the divergence for intraspecific scaling and interspecific scaling relationships for M L versus M S and M L versus M R , but not for M S versus M R and M A versus M R . We conclude, therefore, that a nearly isometric scaling relationship of M A versus M R holds true within each of the studied woody species and across them irrespective the negative scaling relationship between leaf and stem.

  19. 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.

  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

    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

  1. Allocation of photosynthesized carbon in an intensively farmed winter wheat-soil system as revealed by14CO2pulse labelling.

    Science.gov (United States)

    Sun, Zhaoan; Chen, Qing; Han, Xiao; Bol, Roland; Qu, Bo; Meng, Fanqiao

    2018-02-16

    Understanding the rhizodeposited carbon (C) dynamics of winter wheat (Triticum aestivum L.), is crucial for soil fertility and C sequestration. Pot-grown winter wheat was pulse labelled with 14 CO 2 at the key growth stages. 14 C in the shoots, roots and soil was measured at 5 or 2 days after 14 C-labelling (DAL 5/2) at each growth stage and at harvest. The 14 C in the shoots increased from 4% of the net 14 C recovered (shoots + roots + soil) during tillering to 53% at harvest. Approximately 14-34% of the net 14 C recovered was incorporated into the soil. Allocation of photosynthesized C was extrapolated from the pot experiment to field condition, assuming a planting density of 1.8 million plants ha -1 . The estimated C input to the soil was 1.7 t C ha -1 , and 0.7 t C ha -1 of root residues was retained after wheat harvest; both values were higher than those previously reported (0.6 and 0.4 t C ha -1 , respectively). Our findings highlight that C tracing during the entire crop season is necessary to quantify the temporal allocation of photosynthesized C, especially the contribution to soil carbon in intensified farming system.

  2. 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

  3. 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...

  4. Impacts of mangrove density on surface sediment accretion, belowground biomass and biogeochemistry in Puttalam Lagoon, Sri Lanka

    Science.gov (United States)

    Phillips, D.H.; Kumara, M.P.; Jayatissa, L.P.; Krauss, Ken W.; Huxham, M.

    2017-01-01

    Understanding the effects of seedling density on sediment accretion, biogeochemistry and belowground biomass in mangrove systems can help explain ecological functioning and inform appropriate planting densities during restoration or climate change mitigation programs. The objectives of this study were to examine: 1) impacts of mangrove seedling density on surface sediment accretion, texture, belowground biomass and biogeochemistry, and 2) origins of the carbon (C) supplied to the mangroves in Palakuda, Puttalam Lagoon, Sri Lanka. Rhizophora mucronata propagules were planted at densities of 6.96, 3.26, 1.93 and 0.95 seedlings m−2along with an unplanted control (0 seedlings m−2). The highest seedling density generally had higher sediment accretion rates, finer sediments, higher belowground biomass, greatest number of fine roots and highest concentrations of C and nitrogen (N) (and the lowest C/N ratio). Sediment accretion rates, belowground biomass (over 1370 days), and C and N concentrations differed significantly between seedling densities. Fine roots were significantly greater compared to medium and coarse roots across all plantation densities. Sulphur and carbon stable isotopes did not vary significantly between different density treatments. Isotope signatures suggest surface sediment C (to a depth of 1 cm) is not derived predominantly from the trees, but from seagrass adjacent to the site.

  5. 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

  6. Effects of elevated CO2 concentration and nitrogen supply on biomass and active carbon of freshwater marsh after two growing seasons in Sanjiang Plain, Northeast China.

    Science.gov (United States)

    Zhao, Guangying; Liu, Jingshuang; Wang, Yang; Dou, Jingxin; Dong, Xiaoyong

    2009-01-01

    An experiments were carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 micromol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > labile oxidable carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.

  7. 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

    The response of the soil carbon cycle to increasing atmospheric CO2 concentration has far reaching consequences for the ecosystem carbon balance under future climatic conditions. We report on work carried out in the Swiss free‐air CO2 enrichment (FACE) experiment, where we used in situ 13CO2...... 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 ... 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...

  8. Functional diversity of carbon-gain, water-use, and leaf-allocation traits in trees of a threatened lowland dry forest in Hawaii.

    Science.gov (United States)

    Sandquist, Darren R; Cordell, Susan

    2007-09-01

    We examined carbon-gain, water-use, and leaf-allocation traits for six tree species of a Hawaiian dry forest to better understand the functional diversity within this threatened ecosystem. Tropical dry forests are among the most endangered ecosystems on Earth, and in Hawaii, as elsewhere, declining biodiversity threatens ecosystem processes that may depend on forest functional diversity. We found broad variation among species including a two-fold difference for mean photosynthetic rate, a greater than three-fold difference for predawn water potential, and a nearly three-fold difference for leaf life span. Principal component analysis showed a clear separation of species based on carbon-gain vs. water-use related axes, and δ(13)C analysis revealed differing limitations (supply vs. demand) on carbon assimilation. The broad functional variation not only spanned traditional classifications (avoiders vs. tolerators), but also included unusual strategies (e.g., fast growth with drought tolerance). Correlations among traits, including leaf life span, leaf mass per area, and %N, followed typical global patterns, but some exceptions appeared as a result of unique life-history characteristics, such as latex-rich sap and root parasitism. Elucidating functional variation provides important information that can be used to link plant biodiversity with ecosystem processes and also facilitate the management and preservation of tropical dry forests and other threatened communities.

  9. 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

    from an empirical perspective and in specific ecological settings or contexts. Belowground interactions operate at different spatial and temporal scales. Due to the relatively low mobility and high survival of organisms in the soil, plants have longer lasting legacy effects belowground than aboveground....... Our current challenge is to understand how aboveground-belowground biotic interactions operate across spatial and temporal scales, and how they depend on, as well as influence, the abiotic environment. Because empirical capacities are too limited to explore all possible combinations of interactions...... 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...

  10. 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...

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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)

  17. Sapwood allocation in tropical trees: a test of hypotheses

    NARCIS (Netherlands)

    Schippers, P.; Vlam, M.; Zuidema, P.A.; Sterck, F.J.

    2015-01-01

    Carbon allocation to sapwood in tropical canopy trees is a key process determining forest carbon sequestration, and is at the heart of tree growth and dynamic global vegetation models (DGVM). Several allocation hypotheses exist including those applying assumptions on fixed allocation, pipe model,

  18. Stored Carbon Dynamics are Controlled by a Combination of Evolutionary, Physiological, and Ecological Pressures

    Science.gov (United States)

    Aubrey, D. P.; Mims, J. T.; Oswald, S. W.; Teskey, R. O.; Mitchell, R. J.

    2016-12-01

    Allocation of assimilated carbon to storage provides a critical carbohydrate buffer when metabolic demands exceed current photosynthetic supply; however, our process-level understanding of controls on carbon storage pools and fluxes remains relatively poor. Recent studies have shifted the paradigm from the concept that stored carbon pools are a sink of low priority that accumulate passively when photosynthetic inputs exceed demand toward the concept that these pools are active sinks of high priority. It follows that allocation toward storage—at the expense of growth—is a trait that would be under selective pressure since species that allocate toward storage should be more resilient to disturbance. Using fire-dependent longleaf pine in a series of manipulative and observational studies, we explore how stored carbon dynamics are controlled by a combination of evolutionary, physiological, and ecological pressures. Our manipulative studies revealed large stored carbon pools in roots that maintained belowground metabolism for a year after current photosynthetic supply was restricted. Likewise, the concentration of stored carbon in the smallest, most metabolically active roots was not influenced until nearly one year later. Our observational studies indicated that stored carbon pools differ among closely related species with overlapping natural distributions, but evolutionary histories of different disturbance frequencies and thus, different selective pressures on carbon storage. Our comparisons of stored carbon pools between longleaf trees growing under xeric or mesic soil moisture regimes indicated that allocation toward storage exhibits plasticity through space and time in response to both short- and long-term variations in resource availability. We expect a continuum of responses to disturbances related to ecological niche and evolutionary adaptation that influence the availability of carbohydrates for metabolic demands. We also expect a continuum in stored

  19. 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.)

  20. 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

  1. Empirical and theoretical challenges in aboveground–belowground ecology

    NARCIS (Netherlands)

    Van der Putten, W.H.; Bardgett, R.D.; de Ruiter, P.C.; Hol, W.H.G.; Meyer, K.M.; Bezemer, T.M.; Bradford, M.A.; Christensen, S.; Eppinga, M.B.; Fukami, T.; Hemerik, L.; Molofsky, J.; Schädler, M.; Scherber, C.; Strauss, S.Y.; Vos, M.; Wardle, D.A.

    2009-01-01

    A growing body of evidence shows that aboveground and belowground communities and processes are intrinsically linked, and that feedbacks between these subsystems have important implications for community structure and ecosystem functioning. Almost all studies on this topic have been carried out from

  2. Empirical and theoretical challenges in aboveground-belowground ecology

    NARCIS (Netherlands)

    Putten, van der W.H.; Bardgett, R.D.; Ruiter, de P.C.; Hol, W.H.G.; Meyer, K.M.; Bezemer, T.M.; Bradford, M.A.; Christensen, S.; Eppinga, M.B.; Fukami, T.; Hemerik, L.; Molofsky, J.; Schädler, M.; Scherber, C.; Strauss, S.Y.; Vos, M.; Wardle, D.A.

    2009-01-01

    A growing body of evidence shows that aboveground and belowground communities and processes are intrinsically linked, and that feedbacks between these subsystems have important implications for community structure and ecosystem functioning. Almost all studies on this topic have been carried out from

  3. A landscape-scale assessment of above- and belowground primary production in coastal wetlands: Implications for climate change-induced community shifts

    Science.gov (United States)

    Stagg, Camille L.; Schoolmaster, Donald R.; Piazza, Sarai C.; Snedden, Gregg; Steyer, Gregory D.; Fischenich, Craig J; McComas, Robert W.

    2017-01-01

    Above- and belowground production in coastal wetlands are important contributors to carbon accumulation and ecosystem sustainability. As sea level rises, we can expect shifts to more salt-tolerant communities, which may alter these ecosystem functions and services. Although the direct influence of salinity on species-level primary production has been documented, we lack an understanding of the landscape-level response of coastal wetlands to increasing salinity. What are the indirect effects of sea-level rise, i.e., how does primary production vary across a landscape gradient of increasing salinity that incorporates changes in wetland type? This is the first study to measure both above- and belowground production in four wetland types that span an entire coastal gradient from fresh to saline wetlands. We hypothesized that increasing salinity would limit rates of primary production, and saline marshes would have lower rates of above- and belowground production than fresher marshes. However, along the Northern Gulf of Mexico Coast in Louisiana, USA, we found that aboveground production was highest in brackish marshes, compared with fresh, intermediate, and saline marshes, and belowground production was similar among all wetland types along the salinity gradient. Multiple regression analysis indicated that salinity was the only significant predictor of production, and its influence was dependent upon wetland type. We concluded that (1) salinity had a negative effect on production within wetland type, and this relationship was strongest in the fresh marsh (0–2 PSU) and (2) along the overall landscape gradient, production was maintained by mechanisms at the scale of wetland type, which were likely related to plant energetics. Regardless of wetland type, we found that belowground production was significantly greater than aboveground production. Additionally, inter-annual variation, associated with severe drought conditions, was observed exclusively for belowground

  4. Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity.

    Science.gov (United States)

    Vidović, Marija; Morina, Filis; Milić, Sonja; Albert, Andreas; Zechmann, Bernd; Tosti, Tomislav; Winkler, Jana Barbro; Jovanović, Sonja Veljović

    2015-08-01

    We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 μmol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  5. 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.

  6. Belowground processes regulate ecosystem nitrogen retention during a multi-year forest dieback event

    Science.gov (United States)

    Nave, L. E.; Le Moine, J.; Gough, C. M.; Vogel, C.; Nadelhoffer, K. J.; Curtis, P.

    2013-12-01

    In the absence of disturbances, forests typically have strong retention capacity for nitrogen (N), which is internally recycled between soil, microbial and plant pools. However, disturbances that trigger senescence or mortality of forest vegetation may alter internal N cycling processes and lead to the loss of ecosystem N retention capacity. Here, we present an assessment of the role played by belowground processes in governing ecosystem N cycling and retention during an experimental disturbance that killed the dominant canopy taxa in a Great Lakes forest over a 4-year period. After applying stem girdling to hasten the age-related senescence of the dominant taxa (Populus and Betula spp.; ~35% of the basal area), we observed a 38% decrease in stand-level allocation of nonstructural carbohydrates to fine roots, which triggered a tenfold increase in the rate of fine root turnover and increased soil NH4+ and NO3- availability. Elevated soil N availability decreased mycorrhizal hyphal foraging and N uptake, effectively down-regulating the role of symbiotic fungi in the N nutrition of the residual (longer-lived) tree taxa. However, even as residual trees took up less N from mycorrhizal sources, their overall N uptake increased and served to offset the loss of the dominant taxa. The net result of this offset was that canopy N stocks remained constant through the disturbance period and there was no appreciable loss of ecosystem N stocks due to leaching or gaseous export. In sum, the cascade of changes in root, microbial, and soil processes during this experiment indicates that these interdependent components of the belowground system comprised a mechanism responsible for retention and redistribution of ecosystem N stocks during the disturbance period.

  7. 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

    allocation scheme taking into account drought-induced changes in allocation dynamics and acclimation of respiration. Model validation was performed against extensive datasets of C fluxes and C pools for a 9 years period (2000-2008) for the site of parameterisation (the beech forest of Hesse, France...... 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...... of drought-induced changes in fine root dynamics and of short-term thermal acclimation of maintenance respiration should not be overlooked when simulating the C cycle of forests, particularly for sites likely to experience extreme drought and heat waves. The most relevant model bias was the inaccurate...

  8. 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...

  9. Seasonal switchgrass ecotype contributions to soil organic carbon, deep soil microbial community composition and rhizodeposit uptake during an extreme drought

    Science.gov (United States)

    The importance of rhizodeposit C and associated microbial communities in deep soil C stabilization is relatively unknown. Phenotypic variability in plant root biomass could impact C cycling through belowground plant allocation, rooting architecture, and microbial community abundance and composition...

  10. 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.

  11. Effects of waterlogging on carbon assimilate partitioning in the Zoigê alpine wetlands revealed by 13CO2 pulse labeling.

    Science.gov (United States)

    Gao, Jun-Qin; Gao, Ju-Juan; Zhang, Xue-Wen; Xu, Xing-Liang; Deng, Zhao-Heng; Yu, Fei-Hai

    2015-03-23

    Waterlogging has been suggested to affect carbon (C) turnover in wetlands, but how it affects C allocation and stocks remains unclear in alpine wetlands. Using in situ (13)CO2 pulse labelling, we investigated C allocation in both waterlogged and non-waterlogged sites in the Zoigê wetlands on the Tibetan Plateau in August 2011. More than 50% of total (13)C fixed by photosynthesis was lost via shoot respiration. Shoots recovered about 19% of total (13)C fixed by photosynthesis at both sites. Only about 26% of total fixed (13)C was translocated into the belowground pools. Soil organic C pool accounted for 19% and roots recovered about 5-7% of total fixed (13)C at both sites. Waterlogging significantly reduced soil respiration and very little (13)C was lost via soil respiration in the alpine wetlands compared to that in grasslands. We conclude that waterlogging did not significantly alter C allocations among the C pools except the (13)CO2 efflux derived from soil respiration and that shoots made similar contributions to C sequestration as the belowground parts in the Zoigê alpine wetlands. Therefore, changes in waterlogging due to climate change will not affect C assimilate partitioning but soil C efflux.

  12. 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.

  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. 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

  15. 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.

  16. 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.

  17. 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...

  18. 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,...

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

    DEFF Research Database (Denmark)

    Stevnsbak, Karen; Scherber, Christoph; Gladbach, David

    2012-01-01

    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.......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...... 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...

  20. Does drought legacy alter the recovery of grassland carbon dynamics from drought?

    Science.gov (United States)

    Bahn, Michael; Hasibeder, Roland; Fuchslueger, Lucia; Ingrisch, Johannes; Ladreiter-Knauss, Thomas; Lair, Georg; Reinthaler, David; Richter, Andreas; Kaufmann, Rüdiger

    2017-04-01

    Climate projections suggest an increase in the frequency and the severity of extreme climatic events, such as droughts, with consequences for the carbon cycle and its feedbacks to the climate system. An important implication of increasing drought frequency is that possible legacies of previous droughts may increasingly affect ecosystem responses to new drought events, though this has been rarely tested. Based on a series of severe experimental droughts performed during nine subsequent years on a mountain grassland in the Austrian Alps, we present evidence of effects of drought legacies on the recovery of grassland carbon dynamics from drought and analyse the underlying mechanisms. Both single and recurrent droughts led to increased aboveground productivity during drought recovery relative to control plots, favoring the biomass production and leaf area of grass species more strongly than of forbs. Belowground productivity was significantly increased during recovery. This led to higher total root length, even though specific root length was strongly reduced during recovery, particularly after recurrent drought events. Following rewetting, the temperature dependence of soil respiration was increasingly diminished and the Birch effect declined with progressive recurrence of droughts. This was paralleled by a change in soil aggregate stability and soil porosity in plots repeatedly exposed to drought. Isotopic pulse-labelling experiments revealed effects of drought legacy on plant carbon uptake and belowground allocation and altered microbial turnover of recent plant-derived carbon during and after a subsequent drought. Shifts in tissue nitrogen concentration indicate that drought effects on soil nitrogen turnover and availability could play an important role in the recovery of grassland carbon dynamics following both single and recurrent droughts. In conclusion, drought legacies can alter the recovery of grassland carbon dynamics from drought, the effects increasing

  1. 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.

  2. Net assimilation and photosynthate allocation of Populus clones grown under short-rotation intensive culture: Physiological and genetic responses regulating yield

    Energy Technology Data Exchange (ETDEWEB)

    Dickmann, D.I.; Pregitzer, K.S.; Nguyen, P.V. [Michigan State Univ., East Lansing, MI (United States)

    1996-08-01

    The overall objective of this project was to determine the differential responses of poplar clones from sections Tacamahaca and Aigeiros of the genus Populus to varying levels of applied water and nitrogen. Above- and below-ground phenology and morphology, photosynthate allocation, and physiological processes were examined. By manipulating the availability of soil resources, we have been able to separate inherent clonal differences from plastic responses, and to determine genotype-environment interactions. We also have been able to make some contrasts between trees grown from hardwood cuttings and coppice sprouts. Our overall hypothesis was that carbon allocation during growth is greatly influenced by interactions among moisture, nitrogen, and genotype, and that these interactions greatly influence yield in short-rotation plantations. As is true of any project, some of our original expectations were not realized, whereas other initially unforeseen results were obtained. The reduced funding from the Biofuels Feedstock Development Program (BFDP) during the last few years of the project slowed us down to some extent, so progress was not been as rapid as we might have hoped. The major problem associated with this funding shortfall was the inability to employ skilled and unskilled student labor. Nonetheless, we were able to accomplish most of our original goals. All of the principal investigators on this project feel that we have made progress in advancing the scientific underpinning of short-rotation woody biomass production.

  3. ECOLOGICAL AND EVOLUTIONARY IMPLICATIONS OF CARBON ALLOCATION IN MARINE PHYTOPLANKTON AS A FUNCTION OF NITROGEN AVAILABILITY: A FOURIER TRANSFORM INFRARED SPECTROSCOPY APPROACH(1).

    Science.gov (United States)

    Palmucci, Matteo; Ratti, Simona; Giordano, Mario

    2011-04-01

    An imbalance in the cellular C:N ratio may appreciably affect C allocation in algal cells. The consequences of these rearrangements of cellular pools on cell energetics, ecological fitness, and evolutionary trajectories are little known, although they are expected to be substantial. We investigated the fate of C in 11 microalgae cultured semicontinuously at three [NO3 (-) ] and constant pCO2 . We developed a new computational method for the semiquantitative use of Fourier transform infrared (FTIR) spectroscopy data for the determination of macromolecular composition. No obvious relationship was observed between the taxonomy and the allocation strategies adopted by the 11 species considered in this study. Not all species responded to a lower N availability by accumulating lipids or carbohydrates: Dunaliella parva W. Lerche and Thalassiosira pseudonana Hasle et Heimdal were homeostatic with respect to organic cell composition. A hyperbolic dependence of the lipid concentration from cell volume was observed. The level of reduction of organic constituents of green algae was parabolically related to size and was modulated in response to changes in N availability; the same was not true for the species bearing a "red" chloroplast. The above observations are discussed with respect to phytoplankton species composition and palatability for grazers, oleogenesis, and overall cell energetics. © 2011 Phycological Society of America.

  4. 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.

  5. Aboveground and belowground responses to nutrient additions and herbivore exclusion in Arctic tundra ecosystems in northern Alaska

    Science.gov (United States)

    Moore, J. C.; Gough, L.; Simpson, R.; Johnson, D. R.

    2011-12-01

    The Arctic has experienced significant increased regional warming over the past 30 years. Warming generally increases tundra soil nutrient availability by creating a more favorable environment for plant growth, decomposition and nutrient mineralization. Aboveground there has been a "greening" of the Arctic with increased net primary productivity (NPP), and an increase in woody vegetation. Concurrent with the changes aboveground has been an increase in root growth at lower depths and a loss of soil organic C (40 -100 g C m-2 yr-1). Given that arctic soils contain 14% of the global soil C pool, understanding the mechanisms behind shifts of this magnitude that are changing arctic soils from a net sink to a net source of atmospheric C is critical. We took an integrated multi-trophic level approach to examine how altering soil nutrients and mammalian herbivore activity affects vegetation, soil fauna, and microbial communities as well as soil physical characteristics in moist acidic (MAT) and dry heath (DH) tundra. Our work was conducted at the Arctic LTER site in northern Alaska. We sampled the nutrient (controls and annual N+P additions) and herbivore (controls and exclosures) manipulations established in 1996 after 10 years of treatment. Models that incorporated the biomass estimates from the field were used to characterize the trophic structure of the belowground food web and to estimate carbon flux among soil organisms and C-mineralization rates. Both MAT and DH exhibited significant increases in NPP and root growth and changes in vegetation structure with transitions from a mixed community to deciduous shrubs in MAT and from lichens to grasses and shrubs in DH, with nutrient additions and herbivore exclosures. Belowground responses to the treatments were dependent on ecosystem type, but exposed alterations in trophic structure that included changes in microbial biomass, the establishment of microbivorous enchytreaids, increases in root-feeding nematodes, and

  6. 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

  7. 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.

  8. 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...

  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. 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

  11. Effects of an Ecosystem Engineer on Belowground Movement of Microarthropods

    Science.gov (United States)

    Cameron, Erin K.; Proctor, Heather C.; Bayne, Erin M.

    2013-01-01

    Ecosystem engineers affect other species by changing physical environments. Such changes may influence movement of organisms, particularly belowground where soil permeability can restrict dispersal. We investigated whether earthworms, iconic ecosystem engineers, influence microarthropod movement. Our experiment tested whether movement is affected by tunnels (i.e., burrows), earthworm excreta (mucus, castings), or earthworms themselves. Earthworm burrows form tunnel networks that may facilitate movement. This effect may be enhanced by excreta, which could provide resources for microarthropods moving along the network. Earthworms may also promote movement via phoresy. Conversely, negative effects could occur if earthworms alter predator-prey relationships or change competitive interactions between microarthropods. We used microcosms consisting of a box connecting a “source” container in which microarthropods were present and a “destination” container filled with autoclaved soil. Treatments were set up within the boxes, which also contained autoclaved soil, as follows: 1) control with no burrows; 2) artificial burrows with no excreta; 3) abandoned burrows with excreta but no earthworms; and 4) earthworms (Lumbricus rubellus) present in burrows. Half of the replicates were sampled once after eight days, while the other half were sampled repeatedly to examine movement over time. Rather than performing classical pairwise comparisons to test our hypotheses, we used AICc to assess support for three competing models (presence of tunnels, excreta, and earthworms). More individuals of Collembola, Mesostigmata, and all microarthropods together dispersed when tunnels were present. Models that included excreta and earthworms were less well supported. Total numbers of dispersing Oribatida and Prostigmata+Astigmata were not well explained by any models tested. Further research is needed to examine the impact of soil structure and ecosystem engineering on movement

  12. Effects of an ecosystem engineer on belowground movement of microarthropods.

    Directory of Open Access Journals (Sweden)

    Erin K Cameron

    Full Text Available Ecosystem engineers affect other species by changing physical environments. Such changes may influence movement of organisms, particularly belowground where soil permeability can restrict dispersal. We investigated whether earthworms, iconic ecosystem engineers, influence microarthropod movement. Our experiment tested whether movement is affected by tunnels (i.e., burrows, earthworm excreta (mucus, castings, or earthworms themselves. Earthworm burrows form tunnel networks that may facilitate movement. This effect may be enhanced by excreta, which could provide resources for microarthropods moving along the network. Earthworms may also promote movement via phoresy. Conversely, negative effects could occur if earthworms alter predator-prey relationships or change competitive interactions between microarthropods. We used microcosms consisting of a box connecting a "source" container in which microarthropods were present and a "destination" container filled with autoclaved soil. Treatments were set up within the boxes, which also contained autoclaved soil, as follows: 1 control with no burrows; 2 artificial burrows with no excreta; 3 abandoned burrows with excreta but no earthworms; and 4 earthworms (Lumbricus rubellus present in burrows. Half of the replicates were sampled once after eight days, while the other half were sampled repeatedly to examine movement over time. Rather than performing classical pairwise comparisons to test our hypotheses, we used AIC(c to assess support for three competing models (presence of tunnels, excreta, and earthworms. More individuals of Collembola, Mesostigmata, and all microarthropods together dispersed when tunnels were present. Models that included excreta and earthworms were less well supported. Total numbers of dispersing Oribatida and Prostigmata+Astigmata were not well explained by any models tested. Further research is needed to examine the impact of soil structure and ecosystem engineering on movement

  13. 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

  14. 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

  15. 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.

  16. Dynamic Channel Allocation

    Science.gov (United States)

    2003-09-01

    21 9. Beowulf Ethernet Channel Bonding.................................................22 F. SUMMARY...on demand, hybrid channel allocation in wireless networks, and 3 Beowulf Ethernet channel bonding. The background information presented in this...channels are available for dynamic allocation [Ref 32]. 9. Beowulf Ethernet Channel Bonding A by-product of using older computers in a NASA research lab

  17. 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...... rate and increased non-photochemical quenching (NPQ) in ‘1110’ but not in ‘Vinjett’. With AMF, nitrogen concentrations increased in roots of both cultivars, but decreased in grains of ‘Vinjett’ and in side-tiller grains of ‘1110’ regardless of water status. With water deficits, AMF colonization...

  18. 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

  19. The links between ecosystem multifunctionality and above- and belowground biodiversity are mediated by climate

    Science.gov (United States)

    Jing, Xin; Sanders, Nathan J.; Shi, Yu; Chu, Haiyan; Classen, Aimée T.; Zhao, Ke; Chen, Litong; Shi, Yue; Jiang, Youxu; He, Jin-Sheng

    2015-01-01

    Plant biodiversity is often correlated with ecosystem functioning in terrestrial ecosystems. However, we know little about the relative and combined effects of above- and belowground biodiversity on multiple ecosystem functions (for example, ecosystem multifunctionality, EMF) or how climate might mediate those relationships. Here we tease apart the effects of biotic and abiotic factors, both above- and belowground, on EMF on the Tibetan Plateau, China. We found that a suite of biotic and abiotic variables account for up to 86% of the variation in EMF, with the combined effects of above- and belowground biodiversity accounting for 45% of the variation in EMF. Our results have two important implications: first, including belowground biodiversity in models can improve the ability to explain and predict EMF. Second, regional-scale variation in climate, and perhaps climate change, can determine, or at least modify, the effects of biodiversity on EMF in natural ecosystems. PMID:26328906

  20. An invasive wetland grass primes deep soil carbon pools.

    Science.gov (United States)

    Bernal, Blanca; Megonigal, J Patrick; Mozdzer, Thomas J

    2017-05-01

    Understanding the processes that control deep soil carbon (C) dynamics and accumulation is of key importance, given the relevance of soil organic matter (SOM) as a vast C pool and climate change buffer. Methodological constraints of measuring SOM decomposition in the field prevent the addressing of real-time rhizosphere effects that regulate nutrient cycling and SOM decomposition. An invasive lineage of Phragmites australis roots deeper than native vegetation (Schoenoplectus americanus and Spartina patens) in coastal marshes of North America and has potential to dramatically alter C cycling and accumulation in these ecosystems. To evaluate the effect of deep rooting on SOM decomposition we designed a mesocosm experiment that differentiates between plant-derived, surface SOM-derived (0-40 cm, active root zone of native marsh vegetation), and deep SOM-derived mineralization (40-80 cm, below active root zone of native vegetation). We found invasive P. australis allocated the highest proportion of roots in deeper soils, differing significantly from the native vegetation in root : shoot ratio and belowground biomass allocation. About half of the CO 2 produced came from plant tissue mineralization in invasive and native communities; the rest of the CO 2 was produced from SOM mineralization (priming). Under P. australis, 35% of the CO 2 was produced from deep SOM priming and 9% from surface SOM. In the native community, 9% was produced from deep SOM priming and 44% from surface SOM. SOM priming in the native community was proportional to belowground biomass, while P. australis showed much higher priming with less belowground biomass. If P. australis deep rooting favors the decomposition of deep-buried SOM accumulated under native vegetation, P. australis invasion into a wetland could fundamentally change SOM dynamics and lead to the loss of the C pool that was previously sequestered at depth under the native vegetation, thereby altering the function of a wetland

  1. 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

  2. Above- and belowground herbivory jointly impact defense and seed dispersal traits in Taraxacum officinale

    OpenAIRE

    de la Peña, Eduardo; Bonte, Dries

    2014-01-01

    Plants are able to cope with herbivores by inducing defensive traits or growth responses that allow them to reduce or avoid the impact of herbivores. Since above- and belowground herbivores differ substantially in life-history traits, for example feeding types, and their spatial distribution, it is likely that they induce different responses in plants. Moreover, strong interactive effects on defense and plant growth are expected when above- and belowground herbivores are jointly present. The ...

  3. 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...... 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...... no persistent changes over the years. Responses of aboveground and belowground biomass were coupled, and Deschampsia flexuosa showed high ability to adapt to treatments. As the major response was observed belowground, I further studied decomposition of fine roots. Fine roots of Deschampsia flexuosa from deep...

  4. Analysis of standard and innovative methods for allocating upstream and refinery GHG emissions to oil products

    NARCIS (Netherlands)

    Moretti, Christian; Moro, Alberto; Edwards, Robert A; Rocco, Matteo Vincenzo; Colombo, Emanuela

    2017-01-01

    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

  5. 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)

  6. Biomass allocation patterns across China's terrestrial biomes.

    Directory of Open Access Journals (Sweden)

    Limei Wang

    Full Text Available Root to shoot ratio (RS is commonly used to describe the biomass allocation between below- and aboveground parts of plants. Determining the key factors influencing RS and interpreting the relationship between RS and environmental factors is important for biological and ecological research. In this study, we compiled 2088 pairs of root and shoot biomass data across China's terrestrial biomes to examine variations in the RS and its responses to biotic and abiotic factors including vegetation type, soil texture, climatic variables, and stand age. The median value of RS (RSm for grasslands, shrublands, and forests was 6.0, 0.73, and 0.23, respectively. The range of RS was considerably wide for each vegetation type. RS values for all three major vegetation types were found to be significantly correlated to mean annual precipitation (MAP and potential water deficit index (PWDI. Mean annual temperature (MAT also significantly affect the RS for forests and grasslands. Soil texture and forest origin altered the response of RS to climatic factors as well. An allometric formula could be used to well quantify the relationship between aboveground and belowground biomass, although each vegetation type had its own inherent allometric relationship.

  7. 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.

  8. 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.

  9. 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.

  10. Carbon Storage in Tagus Salt Marsh Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Cacador, Isabel, E-mail: icacador@fc.ul.pt; Costa, Ana Luisa [University of Lisbon, Institute of Oceanography, Faculty of Sciences (Portugal); Vale, Carlos [Institute for Sea and Fisheries Research (IPIMAR) (Portugal)

    2004-06-15

    Seasonal variation of above ground and belowground biomass of Spartina maritima and Halimione portulacoides, decomposition rates of belowground detritus in litterbags, and carbon partitioning in plant components and sediments were determined in two Tagus estuary marshes with different environmental conditions. Total biomass was higher in the saltier marsh from 7,190 to 6,593 g m{sup -2} dw and below ground component contributed to more than 90%. Litterbag experiment showed that 30 to 50% of carbonis decomposed within a month (decomposition rate from 0.024 to 0.060 d{sup -1}). Slower decomposition in subsequent periods agrees with accumulation of carbon concentration in sediment. Atmospheric carbon annually transferred to the plant belowground biomass is stored more efficiently in sediments of Corroios than Pancas.

  11. Shrub encroachment in Arctic tundra: Betula nana effects on above- and belowground litter decomposition.

    Science.gov (United States)

    McLaren, Jennie R; Buckeridge, Kate M; van de Weg, Martine J; Shaver, Gaius R; Schimel, Joshua P; Gough, Laura

    2017-05-01

    Rapid arctic vegetation change as a result of global warming includes an increase in the cover and biomass of deciduous shrubs. Increases in shrub abundance will result in a proportional increase of shrub litter in the litter community, potentially affecting carbon turnover rates in arctic ecosystems. We investigated the effects of leaf and root litter of a deciduous shrub, Betula nana, on decomposition, by examining species-specific decomposition patterns, as well as effects of Betula litter on the decomposition of other species. We conducted a 2-yr decomposition experiment in moist acidic tundra in northern Alaska, where we decomposed three tundra species (Vaccinium vitis-idaea, Rhododendron palustre, and Eriophorum vaginatum) alone and in combination with Betula litter. Decomposition patterns for leaf and root litter were determined using three different measures of decomposition (mass loss, respiration, extracellular enzyme activity). We report faster decomposition of Betula leaf litter compared to other species, with support for species differences coming from all three measures of decomposition. Mixing effects were less consistent among the measures, with negative mixing effects shown only for mass loss. In contrast, there were few species differences or mixing effects for root decomposition. Overall, we attribute longer-term litter mass loss patterns to patterns created by early decomposition processes in the first winter. We note numerous differences for species patterns between leaf and root decomposition, indicating that conclusions from leaf litter experiments should not be extrapolated to below-ground decomposition. The high decomposition rates of Betula leaf litter aboveground, and relatively similar decomposition rates of multiple species below, suggest a potential for increases in turnover in the fast-decomposing carbon pool of leaves and fine roots as the dominance of deciduous shrubs in the Arctic increases, but this outcome may be tempered by

  12. ABA and GA3 increase carbon allocation in different organs of grapevine plants by inducing accumulation of non-structural carbohydrates in leaves, enhancement of phloem area and expression of sugar transporters.

    Science.gov (United States)

    Murcia, Germán; Pontin, Mariela; Reinoso, Herminda; Baraldi, Rita; Bertazza, Gianpaolo; Gómez-Talquenca, Sebastián; Bottini, Rubén; Piccoli, Patricia N

    2016-03-01

    Grape quality for winemaking depends on sugar accumulation and metabolism in berries. Abscisic acid (ABA) and gibberellins (GAs) have been reported to control sugar allocation in economically important crops, although the mechanisms involved are still unknown. The present study tested if ABA and gibberellin A3 (GA3) enhance carbon allocation in fruits of grapevines by modifying phloem loading, phloem area and expression of sugar transporters in leaves and berries. Pot-grown Vitis vinifera cv. Malbec plants were sprayed with ABA and GA3 solutions. The amount of soluble sugars in leaves and berries related to photosynthesis were examined at three points of berry growth: pre-veraison, full veraison and post-veraison. Starch levels and amylase activity in leaves, gene expression of sugar transporters in leaves and berries and phloem anatomy were examined at full veraison. Accumulation of glucose and fructose in berries was hastened in ABA-treated plants at the stage of full veraison, which was correlated with enhancement of Vitis vinifera HEXOSE TRANSPORTER 2 (VvHT2) and Vitis vinifera HEXOSE TRANSPORTER 6 (VvHT6) gene expression, increases of phloem area and sucrose content in leaves. On the other hand, GA3 increased the quantity of photoassimilates delivered to the stem thus increasing xylem growth. In conclusion, stimulation of sugar transport by ABA and GA3 to berries and stems, respectively, was due to build-up of non-structural carbohydrates in leaves, modifications in phloem tissue and modulation in gene expression of sugar transporters. © 2015 Scandinavian Plant Physiology Society.

  13. 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,...

  14. 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.

  15. 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

  16. 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.

  17. 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 th...... 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.......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...

  18. Untangling above- and belowground mycorrhizal fungal networks in tropical orchids.

    Science.gov (United States)

    Leake, J R; Cameron, D D

    2012-10-01

    Orchids typically depend on fungi for establishment from seeds, forming mycorrhizal associations with basidiomycete fungal partners in the polyphyletic group rhizoctonia from early stages of germination, sometimes with very high specificity. This has raised important questions about the roles of plant and fungal phylogenetics, and their habitat preferences, in controlling which fungi associate with which plants. In this issue of Molecular Ecology, Martos et al. (2012) report the largest network analysis to date for orchids and their mycorrhizal fungi, sampling a total of over 450 plants from nearly half the 150 tropical orchid species on Reunion Island, encompassing its main terrestrial and epiphytic orchid genera. The authors found a total of 95 operational taxonomic units of mycorrhizal fungi and investigated the architecture and nestedness of their bipartite networks with 73 orchid species. The most striking finding was a major ecological barrier between above- and belowground mycorrhizal fungal networks, despite both epiphytic and terrestrial orchids often associating with closely related taxa across all three major lineages of rhizoctonia fungi. The fungal partnerships of the epiphytes and terrestrial species involved a diversity of fungal taxa in a modular network architecture, with only about one in ten mycorrhizal fungi partnering orchids in both groups. In contrast, plant and fungal phylogenetics had weak or no effects on the network. This highlights the power of recently developed ecological network analyses to give new insights into controls on plant-fungal symbioses and raises exciting new hypotheses about the differences in properties and functioning of mycorrhiza in epiphytic and terrestrial orchids. © 2012 Blackwell Publishing Ltd.

  19. Arbuscular mycorrhizal colonization on carbon economy in perennial ryegrass: quantification by 13CO2/12CO2 steady-state labelling and gas exchange.

    Science.gov (United States)

    Grimoldi, Agustín A; Kavanová, Monika; Lattanzi, Fernando A; Schäufele, Rudi; Schnyder, Hans

    2006-01-01

    Effects of the arbuscular mycorrhizal fungus (AMF) Glomus hoi on the carbon economy of perennial ryegrass (Lolium perenne) were investigated by comparing nonmycorrhizal and mycorrhizal plants of the same size, morphology and phosphorus status. Plants were grown in the presence of CO2 sources with different C isotope composition (delta13C -1 or -44). Relative respiration and gross photosynthesis rates, and belowground allocation of C assimilated during one light period ('new C'), as well as its contribution to respiration, were quantified by the concerted use of 13CO2/12CO2 steady-state labelling and 13CO2/12CO2 gas-exchange techniques. AMF (G. hoi) enhanced the relative respiration rate of the root + soil system by 16%, inducing an extra C flow amounting to 3% of daily gross photosynthesis. Total C flow into AMF growth and respiration was estimated at rates. Therefore the instantaneous relative growth rate was lower in mycorrhizal plants.

  20. Link Monotonic Allocation Schemes

    NARCIS (Netherlands)

    Slikker, M.

    1999-01-01

    A network is a graph where the nodes represent players and the links represent bilateral interaction between the players. A reward game assigns a value to every network on a fixed set of players. An allocation scheme specifies how to distribute the worth of every network among the players. This

  1. 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.

  2. Phenology of perennial native grass below-ground axillary buds in the northern mixed-grass prairie

    Science.gov (United States)

    Vegetative reproduction from belowground bud banks is the primary driver of grassland systems. Despite the importance of vegetative reproduction, the timing of belowground bud recruitment is unknown for most dominant, perennial native grasses as is the relationship between bud development and envir...

  3. 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.

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

    Science.gov (United States)

    Ryalls, James M W; Riegler, Markus; Moore, Ben D; Lopaticki, Goran; Johnson, Scott N

    2013-01-01

    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 colonization 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 across 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 colonization was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonization rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

  5. Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States.

    Science.gov (United States)

    Russell, Matthew B; Domke, Grant M; Woodall, Christopher W; D'Amato, Anthony W

    2015-12-01

    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. Specifically, belowground C stocks are currently estimated in the United States' national greenhouse gas inventory (US NGHGI) using nationally consistent species- and diameter-specific equations applied to individual trees. Recent scientific evidence has pointed to the importance of climate as a driver of belowground C stocks. This study estimates belowground C using current methods applied in the US NGHGI and describes a new approach for merging both allometric models with climate-derived predictions of belowground C stocks. Climate-adjusted predictions were variable depending on the region and forest type of interest, but represented an increase of 368.87 Tg of belowground C across the US, or a 6.4 % increase when compared to currently-implemented NGHGI estimates. Random forests regressions indicated that aboveground biomass, stand age, and stand origin (i.e., planted versus artificial regeneration) were useful predictors of belowground C stocks. Decreases in belowground C stocks were modeled after projecting mean annual temperatures at various locations throughout the US up to year 2090. By combining allometric equations with trends in temperature, we conclude that climate variables can be used to adjust the US NGHGI estimates of belowground C stocks. Such strategies can be used to determine the effects of future global change scenarios within a C accounting framework.

  6. Production possibility frontiers in phototroph:heterotroph symbioses: trade-offs in allocating fixed carbon pools and the challenges these alternatives present for understanding the acquisition of intracellular habitats.

    Science.gov (United States)

    Hill, Malcolm S

    2014-01-01

    Intracellular habitats have been invaded by a remarkable diversity of organisms, and strategies employed to successfully reside in another species' cellular space are varied. Common selective pressures may be experienced in symbioses involving phototrophic symbionts and heterotrophic hosts. Here I refine and elaborate the Arrested Phagosome Hypothesis that proposes a mechanism that phototrophs use to gain access to their host's intracellular habitat. I employ the economic concept of production possibility frontiers (PPF) as a useful heuristic to clearly define the trade-offs that an intracellular phototroph is likely to face as it allocates photosynthetically-derived pools of energy. Fixed carbon can fuel basic metabolism/respiration, it can support mitotic division, or it can be translocated to the host. Excess photosynthate can be stored for future use. Thus, gross photosynthetic productivity can be divided among these four general categories, and natural selection will favor phenotypes that best match the demands presented to the symbiont by the host cellular habitat. The PPF highlights trade-offs that exist between investment in growth (i.e., mitosis) or residency (i.e., translocating material to the host). Insights gained from this perspective might help explain phenomena such as coral bleaching because deficits in photosynthetic production are likely to diminish a symbiont's ability to "afford" the costs of intracellular residency. I highlight deficits in our current understanding of host:symbiont interactions at the molecular, genetic, and cellular level, and I also discuss how semantic differences among scientists working with different symbiont systems may diminish the rate of increase in our understanding of phototrophic-based associations. I argue that adopting interdisciplinary (in this case, inter-symbiont-system) perspectives will lead to advances in our general understanding of the phototrophic symbiont's intracellular niche.

  7. Production possibility frontiers in phototroph:heterotroph symbioses: trade-offs in allocating fixed carbon pools and the challenges these alternatives present for understanding the acquisition of intracellular habitats.

    Directory of Open Access Journals (Sweden)

    Malcolm S. Hill

    2014-07-01

    Full Text Available Intracellular habitats have been invaded by a remarkable diversity of organisms, and strategies employed to successfully reside in another species’ cellular space are varied. Common selective pressures may be experienced in symbioses involving phototrophic symbionts and heterotrophic hosts. Here I refine and elaborate the Arrested Phagosome Hypothesis that proposes a mechanism that phototrophs use to gain access to their host’s intracellular habitat. I employ the economic concept of production possibility frontiers (PPF as a useful heuristic to clearly define the trade-offs that an intracellular phototroph is likely to face as it allocates photosynthetically-derived pools of energy. Fixed carbon can fuel basic metabolism/respiration, it can support mitotic division, or it can be translocated to the host. Excess photosynthate can be stored for future use. Thus, gross photosynthetic productivity can be divided among these four general categories, and natural selection will favor phenotypes that best match the demands presented to the symbiont by the host cellular habitat. The PPF highlights trade-offs that exist between investment in growth (i.e., mitosis or residency (i.e., translocating material to the host. Insights gained from this perspective might help explain phenomena such as coral bleaching because deficits in photosynthetic production are likely to diminish a symbiont’s ability to afford the costs of intracellular residency. I highlight deficits in our current understanding of host:symbiont interactions at the molecular, genetic, and cellular level, and I also discuss how semantic differences among scientists working with different symbiont systems may diminish the rate of increase in our understanding of phototrophic-based associations. I argue that adopting interdisciplinary (in this case, inter-symbiont-system perspectives will lead to advances in our general understanding of the phototrophic symbiont’s intracellular niche.

  8. Soil microbial nutrient constraints along a tropical forest elevation gradient: a belowground test of a biogeochemical paradigm

    Science.gov (United States)

    Nottingham, A. T.; Turner, B. L.; Whitaker, J.; Ostle, N. J.; McNamara, N. P.; Bardgett, R. D.; Salinas, N.; Meir, P.

    2015-10-01

    Aboveground primary productivity is widely considered to be limited by phosphorus (P) availability in lowland tropical forests and by nitrogen (N) availability in montane tropical forests. However, the extent to which this paradigm applies to belowground processes remains unresolved. We measured indices of soil microbial nutrient status in lowland, sub-montane and montane tropical forests along a natural gradient spanning 3400 m in elevation in the Peruvian Andes. With increasing elevation there were marked increases in soil concentrations of total N, total P, and readily exchangeable P, but a decrease in N mineralization determined by in situ resin bags. Microbial carbon (C) and N increased with increasing elevation, but microbial C : N : P ratios were relatively constant, suggesting homeostasis. The activity of hydrolytic enzymes, which are rich in N, decreased with increasing elevation, while the ratio of enzymes involved in the acquisition of N and P increased with increasing elevation, further indicating an increase in the relative demand for N compared to P with increasing elevation. We conclude that soil microorganisms shift investment in nutrient acquisition from P to N between lowland and montane tropical forests, suggesting that different nutrients regulate soil microbial metabolism and the soil carbon balance in these ecosystems.

  9. Influence of windthrows and tree species on forest soil plant biomass and carbon stocks

    Science.gov (United States)

    Veselinovic, B.; Hager, H.

    2012-04-01

    The role of forests has generally been recognized in climate change mitigation and adaptation strategies and policies (e.g. Kyoto Protocol within articles 3.3 and 3.4, RES-E Directive of EU, Country Biomass Action Plans etc.). Application of mitigation actions, to decrease of CO2-emissions and, as the increase of carbon(C)-stocks and appropriate GHG-accounting has been hampered due to a lack of reliable data and good statistical models for the factors influencing C-sequestration in and its release from these systems (e.g. natural and human induced disturbances). Highest uncertainties are still present for estimation of soil C-stocks, which is at the same time the second biggest C-reservoir on earth. Spruce monocultures have been a widely used management practice in central Europe during the past century. Such stands are in lower altitudes (e.g. submontane to lower montane elevation zone) and on heavy soils unstable and prone to disturbances, especially on blowdown. As the windthrow-areas act as CO2-source, we hypothesize that conversion to natural beech and oak forests will provide sustainable wood supply and higher stability of stands against blowdown, which simultaneously provides the long-term belowground C-sequestration. This work focuses on influence of Norway spruce, Common beech and Oak stands on belowground C-dynamics (mineral soil, humus and belowground biomass) taking into consideration the increased impact of windthrows on spruce monocultures as a result of climate change. For this purpose the 300-700m altitude and pseudogley (planosols/temporally logged) soils were chosen in order to evaluate long-term impacts of the observed tree species on belowground C-dynamics and human induced disturbances on secondary spruce stands. Using the false chronosequence approach, the C-pools have been estimated for different compartments and age classes. The sampling of forest floor and surface vegetation was done using 30x30 (homogenous plots) and 50x50cm (inhomogeneous

  10. 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....

  11. Towards Regional, Error-Bounded Landscape Carbon Storage Estimates for Data-Deficient Areas of the World

    DEFF Research Database (Denmark)

    Willcock, Simon; Phillips, Oliver L.; Platts, Philip J.

    2012-01-01

    intervals (CI) for all five IPCC carbon pools (aboveground live carbon, litter, coarse woody debris, belowground live carbon and soil carbon) for data-deficient regions, using a combination of existing inventory data and systematic literature searches, weighted to ensure the final values are regionally...

  12. 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...

  13. 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.

  14. 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...

  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. 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.

  17. 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

  18. Above-belowground interactions govern the course and impact of biological invasions

    DEFF Research Database (Denmark)

    Vestergård, Mette; Rønn, Regin; Ekelund, Flemming

    2015-01-01

    in an evolutionary and ecological context; in the case of invasive plants, we must have a major focus on above-belowground interactions. Thus, we discuss different theories that have been proposed to explain the course of invasions through interactions between plants and soil organisms. Further, a thorough analysis...

  19. 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

  20. 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

  1. Identification of Biologically Relevant Compounds in Aboveground and Belowground Induced Volatile Blends

    NARCIS (Netherlands)

    Dam, van N.M.; Qiu, B.L.; Hordijk, C.A.; Vet, L.E.M.; Jansen, J.J.

    2010-01-01

    Plants under attack by aboveground herbivores emit complex blends of volatile organic compounds (VOCs). Specific compounds in these blends are used by parasitic wasps to find their hosts. Belowground induction causes shifts in the composition of aboveground induced VOC blends, which affect the

  2. 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

  3. 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

  4. Above-ground and below-ground plant responses to fertilization in two subarctic ecosystems

    NARCIS (Netherlands)

    Veen, G.F.; Sundqvist, Maja K.; Metcalfe, D.; Wilson, S.D.

    2015-01-01

    Soil nutrient supply is likely to change in the Arctic due to altered process rates associated with climate change. Here, we compare the responses of herbaceous tundra and birch forest understory to fertilization, considering both above- and below-ground responses. We added nitrogen and phosphorus

  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. Interactions between a belowground herbivore and primary and secondary root metabolites in wild cabbage

    NARCIS (Netherlands)

    Van Geem, Moniek; Harvey, Jeff; Cortesero, A.M.; Raaijmakers, Ciska; 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Tundra fire disturbance homogonizes belowground food web structure, function and dynamics

    Science.gov (United States)

    Moore, J. C.; Pressler, Y.; Koltz, A.; Asmus, A.; Simpson, R.

    2016-12-01

    Tundra fires on Alaska's North Slope are on the rise due to increased lightning strikes since 2000. On July 16, 2007 lightning ignited the Anaktuvuk River fire, burning a 40-by-10 mile swath of tundra about 24 miles north of Toolik Field Station. The fire burned 401 square miles, was visible from space, and released more than 2.3 million tons of carbon into the atmosphere. A large amount of the organic layer of the soil was burned, changing the over all composition of the site and exposing deeper soil horizons. Due to fundamental transitions in soil characteristics and vegetation we hypothesized that the belowground food web community would be affected both in terms of biomass and location within the soil profile. Microbial biomass was reduced with burn severity. In the lower organic horizon there was a significant reduction in fungal biomass but we did not observe this effect in the upper organic soil. We did not observe a significant effect of burn severity on individual group biomass within higher trophic levels. Canonical Discriminant Analysis using the biomass estimates of the functional groups in the food webs found that the webs are becoming increasingly homogenized in the severely burned site compared to the moderately burned and unburned sites. The unburned soils differed significantly from soil at both burn sites; the greatest effects on food web structure were at the lower organic depth, whereas. We modeled the effects of the fire on soil organic matter processing rates and energy flow through the three food webs. The model estimated a decrease in C and N mineralization with fire severity, due in large part to the loss of organic material. While the organic horizon at the unburned site had 12 times greater C and N mineralization than the mineral soils, we observed little to no difference in C and N mineralization between the organic and mineral soil horizons in the moderately and severely burned sites. Our results show that the fire significantly altered

  12. Whole-plant C allocation priorities: do secondary metabolites and VOCs matter?

    Science.gov (United States)

    Hartmann, Henrik; Huang, Jianbei; Forkelova, Lenka; Behrendt, Thomas; Reichelt, Michael; Hammerbacher, Almuth

    2017-04-01

    Whole-plant carbon (C) allocation is a critical issue for understanding plant functioning and has been studied for many decades. Plants fix CO2 from the atmosphere and partition the resulting photosynthetic products (carbohydrates) among several functional pools including growth of structural and reproductive biomass, metabolic processes like respiration but also for the synthesis of secondary metabolites promoting defense and communication. Allocation to secondary metabolites is conceptually viewed as a trade-off between growth and defense. Plants either invest carbohydrates to produce biomass which may be lost - at least partially -to herbivory or they increase allocation to secondary metabolites to deter herbivores from consuming existing biomass. While conceptually intuitive, trade-off hypotheses all suffer from one important shortcoming: the whole-plant carbon balance, critical for determining trade-off relationships, is usually unknown. In the research group on Plant Allocation, we manipulate and measure the whole-plant carbon balance in different species and use tracers to investigate carbon fluxes through the plant and into functional allocation pools. Inducing carbon limitation by reducing atmospheric [CO2] allows us to infer allocation priorities. In this presentation I will show several examples of studies on whole-plant carbon allocation patterns in different plant species. These investigations include assessments of different functional pools like growth, storage, secondary metabolites and volatile emissions as well as the underlying phytohormonal patterns and show that allocation to secondary metabolites and volatiles has a high priority in the whole-plant carbon balance.

  13. 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

  14. 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

  15. Earthworm and belowground competition effects on plant productivity in a plant diversity gradient.

    Science.gov (United States)

    Eisenhauer, Nico; Milcu, Alexandru; Nitschke, Norma; Sabais, Alexander C W; Scherber, Christoph; Scheu, Stefan

    2009-08-01

    Diversity is one major factor driving plant productivity in temperate grasslands. Although decomposers like earthworms are known to affect plant productivity, interacting effects of plant diversity and earthworms on plant productivity have been neglected in field studies. We investigated in the field the effects of earthworms on plant productivity, their interaction with plant species and functional group richness, and their effects on belowground plant competition. In the framework of the Jena Experiment we determined plant community productivity (in 2004 and 2007) and performance of two phytometer plant species [Centaurea jacea (herb) and Lolium perenne (grass); in 2007 and 2008] in a plant species (from one to 16) and functional group richness gradient (from one to four). We sampled earthworm subplots and subplots with decreased earthworm density and reduced aboveground competition of phytometer plants by removing the shoot biomass of the resident plant community. Earthworms increased total plant community productivity (+11%), legume shoot biomass (+35%) and shoot biomass of the phytometer C. jacea (+21%). Further, phytometer performance decreased, i.e. belowground competition increased, with increasing plant species and functional group richness. Although single plant functional groups benefited from higher earthworm numbers, the effects did not vary with plant species and functional group richness. The present study indicates that earthworms indeed affect the productivity of semi-natural grasslands irrespective of the diversity of the plant community. Belowground competition increased with increasing plant species diversity. However, belowground competition was modified by earthworms as reflected by increased productivity of the phytometer C. jacea. Moreover, particularly legumes benefited from earthworm presence. Considering also previous studies, we suggest that earthworms and legumes form a loose mutualistic relationship affecting essential ecosystem

  16. Mean age of carbon in fine roots from temperate forests and grasslands with different management

    Directory of Open Access Journals (Sweden)

    E. Solly

    2013-07-01

    Full Text Available Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (14C content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27 than in forests 3.1 ± 0.5 g (n = 27 (p p r = 0.65 and with the number of perennial species (r = 0.77. Fine root mean C age in grasslands was also affected by study region with averages of 0.7 ± 0.1 yr (n = 9 on mostly organic soils in northern Germany and of 1.8 ± 0.3 yr (n = 9 and 2.6 ± 0.3 (n = 9 in central and southern Germany (p < 0.05. This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

  17. Above- and belowground herbivory jointly impact defense and seed dispersal traits in Taraxacum officinale.

    Science.gov (United States)

    de la Peña, Eduardo; Bonte, Dries

    2014-08-01

    Plants are able to cope with herbivores by inducing defensive traits or growth responses that allow them to reduce or avoid the impact of herbivores. Since above- and belowground herbivores differ substantially in life-history traits, for example feeding types, and their spatial distribution, it is likely that they induce different responses in plants. Moreover, strong interactive effects on defense and plant growth are expected when above- and belowground herbivores are jointly present. The strengths and directions of these responses have been scarcely addressed in the literature. Using Taraxacum officinale, the root-feeding nematode Meloidogyne hapla and the locust Schistocerca gregaria as a model species, we examined to what degree above- and belowground herbivory affect (1) plant growth responses, (2) the induction of plant defensive traits, that is, leaf trichomes, and (3) changes in dispersal-related seed traits and seed germination. We compared the performance of plants originating from different populations to address whether plant responses are conserved across putative different genotypes. Overall, aboveground herbivory resulted in increased plant biomass. Root herbivory had no effect on plant growth. Plants exposed to the two herbivores showed fewer leaf trichomes than plants challenged only by one herbivore and consequently experienced greater aboveground herbivory. In addition, herbivory had effects that reached beyond the individual plant by modifying seed morphology, producing seeds with longer pappus, and germination success.

  18. Aboveground-belowground biodiversity linkages differ in early and late successional temperate forests.

    Science.gov (United States)

    Li, Hui; Wang, Xugao; Liang, Chao; Hao, Zhanqing; Zhou, Lisha; Ma, Sam; Li, Xiaobin; Yang, Shan; Yao, Fei; Jiang, Yong

    2015-07-17

    Understanding ecological linkages between above- and below-ground biota is critical for deepening our knowledge on the maintenance and stability of ecosystem processes. Nevertheless, direct comparisons of plant-microbe diversity at the community level remain scarce due to the knowledge gap between microbial ecology and plant ecology. We compared the α- and β- diversities of plant and soil bacterial communities in two temperate forests that represented early and late successional stages. We documented different patterns of aboveground-belowground diversity relationships in these forests. We observed no linkage between plant and bacterial α-diversity in the early successional forest, and even a negative correlation in the late successional forest, indicating that high bacterial α-diversity is not always linked to high plant α-diversity. Beta-diversity coupling was only found at the late successional stage, while in the early successional forest, the bacterial β-diversity was closely correlated with soil property distances. Additionally, we showed that the dominant competitive tree species in the late successional forest may play key roles in driving forest succession by shaping the soil bacterial community in the early successional stage. This study sheds new light on the potential aboveground-belowground linkage in natural ecosystems, which may help us understand the mechanisms that drive ecosystem succession.

  19. 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.

  20. 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.

  1. Testing the growth rate hypothesis in vascular plants with above- and below-ground biomass.

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    Full Text Available The growth rate hypothesis (GRH proposes that higher growth rate (the rate of change in biomass per unit biomass, μ is associated with higher P concentration and lower C:P and N:P ratios. However, the applicability of the GRH to vascular plants is not well-studied and few studies have been done on belowground biomass. Here we showed that, for aboveground, belowground and total biomass of three study species, μ was positively correlated with N:C under N limitation and positively correlated with P:C under P limitation. However, the N:P ratio was a unimodal function of μ, increasing for small values of μ, reaching a maximum, and then decreasing. The range of variations in μ was positively correlated with variation in C:N:P stoichiometry. Furthermore, μ and C:N:P ranges for aboveground biomass were negatively correlated with those for belowground. Our results confirm the well-known association of growth rate with tissue concentration of the limiting nutrient and provide empirical support for recent theoretical formulations.

  2. 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

  3. Effects of manipulated above- and belowground organic matter input on soil respiration in a Chinese pine plantation.

    Science.gov (United States)

    Fan, Juan; Wang, Jinsong; 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, Q10, 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.

  4. 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

  5. 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

    Partitioning of the quantities of C lost by leaf litter through decomposition into (i) CO2 efflux to the atmosphere and (ii) C input to soil organic matter (SOM) is essential in order to develop a deeper understanding of the litter-soil biogeochemical continuum. However, this is a challenging task...... due to the occurrence of many different processes contributing to litter biomass loss. With the aim of quantifying different fluxes of C lost by leaf litter decomposition, a field experiment was performed at a short rotation coppice poplar plantation in central Italy. Populus nigra leaf litter...... 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...

  6. Completing below-ground carbon budgets for pastures, recovering forests, and mature forests of Amazonia

    Science.gov (United States)

    Davidson, Eric A.; Nepstad, Daniel C.; Trumbore, Susan E.

    1995-01-01

    This progress report covers the following efforts initiated for the year: year-round monthly soil CO2 flux measurements were started in both primary and secondary forests and in managed and degraded pastures; root sorting and weighing has begun and all four ecosystems at Paragominas have been analyzed through samples; regional modeling of soil water dynamics and minimum rooting depth has been done and the RADAMBRASIL soils database has been digitized and a 20 year record of the precipitation for the region has been produced, along with a hydrological ('bucket-tipping') model that will run within a GIS framework; prototype tension lysimeters have been designed and installed in soil pits to begin assessing the importance of DOC as a source of organic matter in deep soils; and many publications, listed in this document, have resulted from this year's research. Two of the papers published are included with this annual report document.

  7. 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

  8. 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.

  9. Biomass Allocation Patterns across China’s Terrestrial Biomes

    Science.gov (United States)

    Wang, Limei; Li, Longhui; Chen, Xi; Tian, Xin; Wang, Xiaoke; Luo, Geping

    2014-01-01

    Root to shoot ratio (RS) is commonly used to describe the biomass allocation between below- and aboveground parts of plants. Determining the key factors influencing RS and interpreting the relationship between RS and environmental factors is important for biological and ecological research. In this study, we compiled 2088 pairs of root and shoot biomass data across China’s terrestrial biomes to examine variations in the RS and its responses to biotic and abiotic factors including vegetation type, soil texture, climatic variables, and stand age. The median value of RS (RSm) for grasslands, shrublands, and forests was 6.0, 0.73, and 0.23, respectively. The range of RS was considerably wide for each vegetation type. RS values for all three major vegetation types were found to be significantly correlated to mean annual precipitation (MAP) and potential water deficit index (PWDI). Mean annual temperature (MAT) also significantly affect the RS for forests and grasslands. Soil texture and forest origin altered the response of RS to climatic factors as well. An allometric formula could be used to well quantify the relationship between aboveground and belowground biomass, although each vegetation type had its own inherent allometric relationship. PMID:24710503

  10. 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...

  11. Carbon emissions from land cover change in Central Vietnam

    NARCIS (Netherlands)

    Avitabile, Valerio; Schultz, Michael; Herold, Nadine; Bruin, De Sytze; Pratihast, Arun Kumar; Manh, Cuong Pham; Quang, Hien Vu; Herold, Martin

    2016-01-01

    The carbon emissions and removals due to land cover changes between 2001 and 2010 in the Vu Gia Thu Bon River Basin, Central Vietnam, were estimated using Landsat satellite images and 3083 forest inventory plots. The net emissions from above- and belowground vegetation biomass were equal to 1.76 ±

  12. Fast discriminative latent Dirichlet allocation

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the code for fast discriminative latent Dirichlet allocation, which is an algorithm for topic modeling and text classification. The related paper is at...

  13. FY12 CPD Formula Allocation

    Data.gov (United States)

    Department of Housing and Urban Development — The Fiscal Year (FY) 2012 budget for the Department of Housing and Urban Development has been enacted. This spreadsheet provide full-year allocations for the Office...

  14. 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...

  15. 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

  16. 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

  17. Get Tough, Get Toxic, or Get a Bodyguard: Identifying Candidate Traits Conferring Belowground Resistance to Herbivores in Grasses.

    Science.gov (United States)

    Moore, Ben D; Johnson, Scott N

    2016-01-01

    Grasses (Poaceae) are the fifth-largest plant family by species and their uses for crops, forage, fiber, and fuel make them the most economically important. In grasslands, which broadly-defined cover 40% of the Earth's terrestrial surface outside of Greenland and Antarctica, 40-60% of net primary productivity and 70-98% of invertebrate biomass occurs belowground, providing extensive scope for interactions between roots and rhizosphere invertebrates. Grasses invest 50-70% of fixed carbon into root construction, which suggests roots are high value tissues that should be defended from herbivores, but we know relatively little about such defenses. In this article, we identify candidate grass root defenses, including physical (tough) and chemical (toxic) resistance traits, together with indirect defenses involving recruitment of root herbivores' natural enemies. We draw on relevant literature to establish whether these defenses are present in grasses, and specifically in grass roots, and which herbivores of grasses are affected by these defenses. Physical defenses could include structural macro-molecules such as lignin, cellulose, suberin, and callose in addition to silica and calcium oxalate. Root hairs and rhizosheaths, a structural adaptation unique to grasses, might also play defensive roles. To date, only lignin and silica have been shown to negatively affect root herbivores. In terms of chemical resistance traits, nitrate, oxalic acid, terpenoids, alkaloids, amino acids, cyanogenic glycosides, benzoxazinoids, phenolics, and proteinase inhibitors have the potential to negatively affect grass root herbivores. Several good examples demonstrate the existence of indirect defenses in grass roots, including maize, which can recruit entomopathogenic nematodes (EPNs) via emission of (E)-β-caryophyllene, and similar defenses are likely to be common. In producing this review, we aimed to equip researchers with candidate root defenses for further research.

  18. 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.

  19. Generalized multidimensional dynamic allocation method.

    Science.gov (United States)

    Lebowitsch, Jonathan; Ge, Yan; Young, Benjamin; Hu, Feifang

    2012-12-10

    Dynamic allocation has received considerable attention since it was first proposed in the 1970s as an alternative means of allocating treatments in clinical trials which helps to secure the balance of prognostic factors across treatment groups. The purpose of this paper is to present a generalized multidimensional dynamic allocation method that simultaneously balances treatment assignments at three key levels: within the overall study, within each level of each prognostic factor, and within each stratum, that is, combination of levels of different factors Further it offers capabilities for unbalanced and adaptive designs for trials. The treatment balancing performance of the proposed method is investigated through simulations which compare multidimensional dynamic allocation with traditional stratified block randomization and the Pocock-Simon method. On the basis of these results, we conclude that this generalized multidimensional dynamic allocation method is an improvement over conventional dynamic allocation methods and is flexible enough to be applied for most trial settings including Phases I, II and III trials. Copyright © 2012 John Wiley & Sons, Ltd.

  20. 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

  1. 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

  2. Coastal Wetland Carbon Dynamics Across a Sediment Delivery Gradient in the Atchafalaya and Terrebonne Basins, Louisiana

    Science.gov (United States)

    McCall, A.; Twilley, R.

    2017-12-01

    The Atchafalaya and Terrebonne Basins of the Mississippi River Deltaic Plain are examples of river-occupied and river-abandoned coastal basins that have undergone coupled natural and anthropogenic changes over time, especially in the last 100 years, influencing their respective coastal wetlands physically and ecologically. These basins provide unique, experimental units of sediment delivery to coastal wetlands to test hypotheses of ecosystem service functioning at multiple time and geographic scales. This study investigates wetland carbon dynamics over time at the basin scale and at the coastal-land margin. We are testing the hypotheses that sediment input via freshwater delivery to coastal deltaic floodplains allows for these systems to develop and perform ecosystem services such as biomass production, which promotes soil carbon accumulation that increases the marsh platform elevation, acting as a carbon sink. Meanwhile, decreased sediment supply to coastal deltaic wetlands in the Terrebonne Basin leads to degradation, subsidence of the marsh platform, and a landward migration of wetlands. This decreases the carbon storage capacity over time and leads to an increase in historic sequestered carbon fluxing out of the system and into coastal waters, thus acting as a carbon source. Using historic soil and vegetation data, we found that since 1949, the wetland soil carbon storage capacity has increased by 47% in the Atchafalaya Basin and decreased by 42% in the Terrebonne Basin. We also examined above and belowground productivity and biomass allocation of dominant emergent species of distinct hydrogeomorphic zones along the coastal-land margin. Soil characteristics have also been measured using short-term feldspar plots across these hydrogeomorphic zones. We also measured particulate carbon, dissolved organic carbon, and suspended sediment concentrations to determine the carbon flux in/out of these systems over a typical tidal cycle. These preliminary findings suggests

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

    Science.gov (United States)

    Li, Qisong; Chen, Jun; Wu, Linkun; Luo, Xiaomian; Li, Na; Arafat, Yasir; Lin, Sheng; Lin, Wenxiong

    2018-02-22

    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.

  4. 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

  5. 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

  6. Coastal landforms and accumulation of mangrove peat increase carbon sequestration and storage

    Science.gov (United States)

    Garcillán, Pedro P.

    2016-01-01

    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. PMID:27035950

  7. 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.

  8. Divergent host preferences of above- and below-ground Culex pipiens mosquitoes and their hybrid offspring.

    Science.gov (United States)

    Fritz, M L; Walker, E D; Miller, J R; Severson, D W; Dworkin, I

    2015-06-01

    Culex pipiens form pipiens and Cx. pipiens form molestus (Diptera: Culicidae) belong to a cosmopolitan taxonomic group known as the Pipiens Assemblage. Hybridization between these forms is thought to contribute to human transmission of West Nile virus (WNV) in North America. Complementary choice and no-choice landing assays were developed to examine host acceptance by North American Cx. pipiens in the laboratory. Populations collected from above- and below-ground sites in suburban Chicago were identified as forms pipiens and molestus using a polymerase chain reaction-based assay. Avian and human host acceptance was then quantified for the two populations, as well as for their hybrid and backcross offspring. No-choice tests were used to demonstrate that both the pipiens and molestus forms were capable of feeding on human and avian hosts. Choice tests were used to demonstrate that form pipiens females were strongly avian-seeking; an individual's probability of accepting the chick host was 85%. Form molestus females were more likely to accept the human host (87%). Rates of host acceptance by F1 and backcross progeny were intermediate to those of their parents. The results suggest that host preferences in Cx. pipiens are genetically determined, and that ongoing hybridization between above- and below-ground populations is an important contributor to epizootic transmission of WNV in North America. © 2015 The Royal Entomological Society.

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

    Science.gov (United States)

    Padilla, Francisco M; Mommer, Liesje; de Caluwe, Hannie; Smit-Tiekstra, Annemiek E; Wagemaker, Cornelis A M; Ouborg, N Joop; de Kroon, Hans

    2013-01-01

    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.

  10. 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...

  11. 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......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...... | generalizations of Gale's Top Trading Cycles mechanism. We study the centralized allocation that takes place in multiple markets. For example, the assignment of multiple types of indivisible objects; or the assignment of objects in successive periods. We show that the set of strategy-proof, Pareto efficient...

  12. Preserving the allocation ratio at every allocation with biased coin randomization and minimization in studies with unequal allocation.

    Science.gov (United States)

    Kuznetsova, Olga M; Tymofyeyev, Yevgen

    2012-04-13

    The demand for unequal allocation in clinical trials is growing. Most commonly, the unequal allocation is achieved through permuted block randomization. However, other allocation procedures might be required to better approximate the allocation ratio in small samples, reduce the selection bias in open-label studies, or balance on baseline covariates. When these allocation procedures are generalized to unequal allocation, special care is to be taken to preserve the allocation ratio at every allocation step. This paper offers a way to expand the biased coin randomization to unequal allocation that preserves the allocation ratio at every allocation. The suggested expansion works with biased coin randomization that balances only on treatment group totals and with covariate-adaptive procedures that use a random biased coin element at every allocation. Balancing properties of the allocation ratio preserving biased coin randomization and minimization are described through simulations. It is demonstrated that these procedures are asymptotically protected against the shift in the rerandomization distribution identified for some examples of minimization with 1:2 allocation. The asymptotic shift in the rerandomization distribution of the difference in treatment means for an arbitrary unequal allocation procedure is explicitly derived in the paper. Copyright © 2011 John Wiley & Sons, Ltd.

  13. 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......-to-one matching model by including a set of objects, such that a matching consists of two agents from disjoint sets, and an object. Agents' preference lists consist of all possible pairs of objects and agents from the other set, and thus contain important information about agent-object tradeoffs. The notion...

  14. 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

  15. 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.

  16. Operational risk economic capital allocation

    Science.gov (United States)

    Nikonov, Oleg I.; Vlasov, Vladimir E.; Medvedeva, Marina A.

    2013-10-01

    In the paper we describe a model of operational risk of economic capital estimation and allocation based on Loss Distribution Approach (LDA). Bank's total losses are modeled through Monte-Carlo simulations of its business units' losses. It allows to fairly distributing the corresponding capital between business units in order to assess and manage their risk adjusted performance.

  17. 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)

  18. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van

    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

  19. Governance and Foreign Aid Allocation

    Science.gov (United States)

    2006-07-01

    In addition, this chapter develops a microeconomic model to explore donors’ aid allocation decisions and their potential impact on aid effectiveness...the promotion of market-based principles to restructure macroeconomic policies in developing countries. The greater focus on...be explained by successful development 29 efforts of number of countries in the region, such as Republic of Korea, Malaysia , Singapore, and Peoples

  20. 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

  1. Above- and below-ground microclimate of grow tubes in an organic mulch-incorporated, raised bed system for blueberry

    Science.gov (United States)

    Grow tubes are well established in forestry and are gaining attention in establishing some woody perennial crops. To date, microclimate descriptions have addressed the above-ground environment, but a mulched raised bed system with organic mulch-incorporated soil requires both above- and below-ground...

  2. 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

  3. 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

  4. 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....

  5. 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

  6. A broadleaf species enhances an autotoxic conifers growth through belowground chemical interactions.

    Science.gov (United States)

    Xia, Zhi-Chao; Kong, Chui-Hua; Chen, Long-Chi; Wang, Peng; Wang, Si-Long

    2016-09-01

    Plants may affect the performance of neighboring plants either positively or negatively through interspecific and intraspecific interactions. Productivity of mixed-species systems is ultimately the net result of positive and negative interactions among the component species. Despite increasing knowledge of positive interactions occurring in mixed-species tree systems, relatively little is known about the mechanisms underlying such interactions. Based on data from 25-year-old experimental stands in situ and a series of controlled experiments, we test the hypothesis that a broadleaf, non-N fixing species, Michelia macclurei, facilitates the performance of an autotoxic conifer Chinese fir (Cunninghamia lanceolata) through belowground chemical interactions. Chinese fir roots released the allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane- 2,5-diketone) into the soil environment, resulting in self-growth inhibition, and deterioration of soil microorganisms that improve P availability. However, when grown with M. macclurei the growth of Chinese fir was consistently enhanced. In particular, Chinese fir enhanced root growth and distribution in deep soil layers. When compared with monocultures of Chinese fir, the presence of M. macclurei reduced release and increased degradation of cyclic dipeptide in the soil, resulting in a shift from self-inhibition to chemical facilitation. This association also improved the soil microbial community by increasing arbuscular mycorrhizal fungi, and induced the production of Chinese fir roots. We conclude that interspecific interactions are less negative than intraspecific ones between non-N fixing broadleaf and autotoxic conifer species. The impacts are generated by reducing allelochemical levels, enhancing belowground mutualisms, improving soil properties, and changing root distributions as well as the net effects of all the processes within the soil. In particular, allelochemical context alters the

  7. Carbon outcomes of major land-cover transitions in SE Asia

    DEFF Research Database (Denmark)

    Ziegler, Alan D.; Phelps, Jacob; Yuen, Jia Qi

    2012-01-01

    , there is little certainty regarding the carbon outcomes of many key land-use transitions at the center of current policy debates. Our meta-analysis of over 250 studies reporting above- and below-ground carbon estimates for different land-use types indicates great uncertainty in the net total ecosystem carbon...... that encourage land-cover conversion away from these [especially long-fallow] systems to other more cash-crop-oriented systems producing ambiguous carbon stock changes GÇô including oil palm and rubber. In some instances, lengthening fallow periods of an existing swidden system may produce substantial carbon...... benefits, as would conversion from intensely cultivated lands to high-biomass plantations and some other types of agroforestry. More field studies are needed to provide better data of above- and below-ground carbon stocks before informed recommendations or policy decisions can be made regarding which land...

  8. 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

  9. 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

    OpenAIRE

    Anastasia Papadopoulou; Stavroula Tsitsifli; Vasilis Kanakoudis

    2012-01-01

    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 ...

  10. 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

    2016-01-01

    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 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. PMID:27009228

  11. 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).

  12. 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

    scale experiment on temperate heathland, manipulation of precipitation and temperature was performed with retractable curtains, and atmospheric CO2 concentration was increased by FACE. The combination of elevated CO2 and warming was expected to affect belowground processes additively, through increased...... (1 year after 13C215N-glycine was injected into the soil) increased in warmed plots and in elevated CO2 plots, but not when these treatments were combined. Furthermore, drought led to an increase in Calluna biomass and total plant nitrogen pool. The full combination of warming, elevated CO2...... and periodic drought did not unambiguously express the ecosystem responses of single factors additively, which complicates predictions of ecosystem responses to multifactor climate change....

  13. 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

  14. 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.

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

    Science.gov (United States)

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

    2016-01-01

    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...

  16. 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...

  17. 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.

  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. Data for developing allometric models and evaluating carbon stocks of the Zambezi Teak Forests in Zambia

    NARCIS (Netherlands)

    Ngoma, Justine; Moors, E.J.; Kruijt, B.; Speer, James H.; Vinya, Royd; Chidumayo, Emmanuel N.; Leemans, H.B.J.

    2018-01-01

    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

  20. 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).

  1. 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.

  2. 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.

  3. Integer Programming Models for Sales Resource Allocation

    OpenAIRE

    Andris A. Zoltners; Prabhakant Sinha

    1980-01-01

    A practical conceptual framework for sales resource allocation modeling is presented in this paper. A literature review of sales resource allocation models is described in terms of this framework. The conceptual framework also lends itself to several integer programming models which may be used to address the variety of sales resource allocation decisions faced by every sales organization. A general model for sales resource allocation is developed which incorporates multiple sales resources, ...

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Changes in biomass allocation buffer low CO2effects on tree growth during the last glaciation.

    Science.gov (United States)

    Li, Guangqi; Gerhart, Laci M; Harrison, Sandy P; Ward, Joy K; Harris, John M; Prentice, I Colin

    2017-02-24

    Isotopic measurements on junipers growing in southern California during the last glacial, when the ambient atmospheric [CO 2 ] (c a ) was ~180 ppm, show the leaf-internal [CO 2 ] (c i ) was approaching the modern CO 2 compensation point for C 3 plants. Despite this, stem growth rates were similar to today. Using a coupled light-use efficiency and tree growth model, we show that it is possible to maintain a stable c i /c a ratio because both vapour pressure deficit and temperature were decreased under glacial conditions at La Brea, and these have compensating effects on the c i /c a ratio. Reduced photorespiration at lower temperatures would partly mitigate the effect of low c i on gross primary production, but maintenance of present-day radial growth also requires a ~27% reduction in the ratio of fine root mass to leaf area. Such a shift was possible due to reduced drought stress under glacial conditions at La Brea. The necessity for changes in allocation in response to changes in [CO 2 ] is consistent with increased below-ground allocation, and the apparent homoeostasis of radial growth, as c a increases today.

  9. Early Root Herbivory Impairs Arbuscular Mycorrhizal Fungal Colonization and Shifts Defence Allocation in Establishing Plantago lanceolata.

    Science.gov (United States)

    Bennett, Alison E; Macrae, Anna M; Moore, Ben D; Caul, Sandra; Johnson, Scott N

    2013-01-01

    Research into plant-mediated indirect interactions between arbuscular mycorrhizal (AM) fungi and insect herbivores has focussed on those between plant shoots and above-ground herbivores, despite the fact that only below-ground herbivores share the same part of the host plant as AM fungi. Using Plantago lanceolata L., we aimed to characterise how early root herbivory by the vine weevil (Otiorhynchus sulcatus F.) affected subsequent colonization by AM fungi (Glomus spp.) and determine how the two affected plant growth and defensive chemistry. We exposed four week old P. lanceolata to root herbivory and AM fungi using a 2×2 factorial design (and quantified subsequent effects on plant biomass and iridoid glycosides (IGs) concentrations. Otiorhynchus sulcatus reduced root growth by c. 64%, whereas plant growth was unaffected by AM fungi. Root herbivory reduced extent of AM fungal colonization (by c. 61%). O. sulcatus did not influence overall IG concentrations, but caused qualitative shifts in root and shoot IGs, specifically increasing the proportion of the more toxic catalpol. These changes may reflect defensive allocation in the plant against further attack. This study demonstrates that very early root herbivory during plant development can shape future patterns of AM fungal colonization and influence defensive allocation in the plant.

  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)

    Ferrenberg, Scott; Martinez, Alexander S; Faist, Akasha M

    2016-01-01

    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. 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. 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 communities and vegetation

  12. The effect of belowground herbivory by wireworms (Coleoptera: Elateridae) on performance of Calamagrostis epigejos (L) Roth in post-mining sites

    Czech Academy of Sciences Publication Activity Database

    Roubíčková, A.; Mudrák, Ondřej; Frouz, J.

    2012-01-01

    Roč. 50, č. 1 (2012), s. 51-55 ISSN 1164-5563 Institutional support: RVO:67985939 Keywords : Belowground herbivory * Wireworms * Calamagrostis epigejos Subject RIV: EH - Ecology, Behaviour Impact factor: 1.838, year: 2012

  13. Cost Allocation and Convex Data Envelopment

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tind, Jørgen

    This paper considers allocation rules. First, we demonstrate that costs allocated by the Aumann-Shapley and the Friedman-Moulin cost allocation rules are easy to determine in practice using convex envelopment of registered cost data and parametric programming. Second, from the linear programming...... 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...

  14. Modelling the influence of ectomycorrhizal decomposition on plant nutrition and soil carbon sequestration in boreal forest ecosystems.

    Science.gov (United States)

    Baskaran, Preetisri; Hyvönen, Riitta; Berglund, S Linnea; Clemmensen, Karina E; Ågren, Göran I; Lindahl, Björn D; Manzoni, Stefano

    2017-02-01

    Tree growth in boreal forests is limited by nitrogen (N) availability. Most boreal forest trees form symbiotic associations with ectomycorrhizal (ECM) fungi, which improve the uptake of inorganic N and also have the capacity to decompose soil organic matter (SOM) and to mobilize organic N ('ECM decomposition'). To study the effects of 'ECM decomposition' on ecosystem carbon (C) and N balances, we performed a sensitivity analysis on a model of C and N flows between plants, SOM, saprotrophs, ECM fungi, and inorganic N stores. The analysis indicates that C and N balances were sensitive to model parameters regulating ECM biomass and decomposition. Under low N availability, the optimal C allocation to ECM fungi, above which the symbiosis switches from mutualism to parasitism, increases with increasing relative involvement of ECM fungi in SOM decomposition. Under low N conditions, increased ECM organic N mining promotes tree growth but decreases soil C storage, leading to a negative correlation between C stores above- and below-ground. The interplay between plant production and soil C storage is sensitive to the partitioning of decomposition between ECM fungi and saprotrophs. Better understanding of interactions between functional guilds of soil fungi may significantly improve predictions of ecosystem responses to environmental change. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  15. 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.

  16. 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

  17. Above–belowground herbivore interactions in mixed plant communities are influenced by altered precipitation patterns

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2016-03-01

    Full Text Available Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralisation and uptake by neighbouring plants and influence plant–plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community composition. Little is known about how climate change may affect these interactions, but an important and timely question is how will grass–legume mixtures respond in a future with an increasing reliance on legume N mineralisation in terrestrial ecosystems. Using a model grass–legume mixture, this study investigated how simultaneous attack on lucerne (Medicago sativa by belowground weevils (Sitona discoideus and aboveground aphids (Acyrthosiphon pisum affected a neighbouring grass (Phalaris aquatica when subjected to drought, ambient and elevated precipitation. Feeding on rhizobial nodules by weevil larvae enhanced soil water retention under ambient and elevated precipitation, but only when aphids were absent. While drought decreased nodulation and root N content in lucerne, grass root and shoot chemistry were unaffected by changes in precipitation. However, plant communities containing weevils but not aphids showed increased grass height and N concentrations, most likely associated with the transfer of N from weevil-attacked lucerne plants containing more nodules and higher root N concentrations compared with insect-free plants. Drought decreased aphid abundance by 54% but increased total and some specific amino acid concentrations (glycine, lysine, methionine, tyrosine, cysteine, histidine, arginine, aspartate and glutamate, suggesting that aphid declines were being driven by other facets of drought (e.g. reduced phloem hydraulics. The presence of weevil larvae

  18. 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

  19. 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.

  20. Surveillance of C-Allocation in Microalgal Cells

    Directory of Open Access Journals (Sweden)

    Heiko Wagner

    2014-06-01

    Full Text Available When microalgae are exposed to changing environmental conditions, e.g., light-dark cycles or oscillations in nutrient availability (CO2, nitrogen, phosphate or silicate they respond with metabolic changes in the carbon allocation pattern. Short time regulations in the time range of few seconds to minutes can be mirrored best by mass spectroscopy based metabolomics. However, these snap shots do not reflect the alterations in the carbon flow to the cellular macromolecules like protein, carbohydrate or lipid. In this review it is shown how the combination of FTIR spectroscopy and Chla-in-vivo-fluorescence based electron transport rates can reveal changes in the metabolic flux rates of carbon during a shift of the environmental conditions. The review will demonstrate in which time range FTIR spectroscopy can deliver significant information and how FTIR spectroscopy data can synergistically support metabolome analysis by mass-spectroscopy.

  1. MtDNA metagenomics reveals large-scale invasion of belowground arthropod communities by introduced species.

    Science.gov (United States)

    Cicconardi, Francesco; Borges, Paulo A V; Strasberg, Dominique; Oromí, Pedro; López, Heriberto; Pérez-Delgado, Antonio J; Casquet, Juliane; Caujapé-Castells, Juli; Fernández-Palacios, José María; Thébaud, Christophe; Emerson, Brent C

    2017-06-01

    Using a series of standardized sampling plots within forest ecosystems in remote oceanic islands, we reveal fundamental differences between the structuring of aboveground and belowground arthropod biodiversity that are likely due to large-scale species introductions by humans. Species of beetle and spider were sampled almost exclusively from single islands, while soil-dwelling Collembola exhibited more than tenfold higher species sharing among islands. Comparison of Collembola mitochondrial metagenomic data to a database of more than 80 000 Collembola barcode sequences revealed almost 30% of sampled island species are genetically identical, or near identical, to individuals sampled from often very distant geographic regions of the world. Patterns of mtDNA relatedness among Collembola implicate human-mediated species introductions, with minimum estimates for the proportion of introduced species on the sampled islands ranging from 45% to 88%. Our results call for more attention to soil mesofauna to understand the global extent and ecological consequences of species introductions. © 2017 John Wiley & Sons Ltd.

  2. 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.

  3. Quantifying below-ground nitrogen of legumes: Optimizing procedures for 15N shoot-labelling

    International Nuclear Information System (INIS)

    Khan, D.F.; Peoples, M.B.; Herridge, D.F.

    2003-01-01

    Quantifying below-ground nitrogen (N) of legumes is fundamental to understanding their effects on soil mineral N fertility and on the N economies of following or companion crops in legume-based rotations. Methodologies based on 15 N-labelling of whole plants with subsequent measurement of 15 N in recovered plant parts and in the root-zone soil have proved promising. We report four glasshouse experiments with objectives to develop appropriate protocols for in situ 15 N labelling of four pulses, faba bean (Vicia faba), chickpea (Cicer arietinum), mung bean (Vigna radiata) and pigeon pea (Cajanus cajan). Treatments included 15 N-urea concentration, feeding technique, leaflet/petiole position, and frequency of feeding. Nitrogen- 15 -labelling via the leaf-flap was best for faba bean, mung and pigeon pea, whilst petiole feeding was best for chickpea, in all cases using 0.2-mL volumes of 0.5% urea (98 atom% 15 N excess). The implications of uneven enrichment of the nodulated roots because of effects of the 15 N-depleted nodules when calculating root-derived N in soil are discussed. (author)

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. Legitimate Allocation of Public Healthcare

    DEFF Research Database (Denmark)

    Lippert-Rasmussen, Kasper; Lauridsen, Sigurd

    2009-01-01

    Citizens' consent to political decisions is often regarded as a necessary condition of political legitimacy. Consequently, legitimate allocation of healthcare has seemed almost unattainable in contemporary pluralistic societies. The problem is that citizens do not agree on any single principle...... governing priorities among groups of patients. The Accountability for Reasonableness (A4R) framework suggests an ingenious solution to this problem of moral disagreement. Rather than advocating any substantive distributive principle, its advocates propose a feasible set of conditions, which, if met...... by decision makers at the institutional level, provide, so it is promised, legitimate decisions. While we agree that A4R represents an important contribution to the priority-setting debate, we challenge the framework in two respects. First, we argue that A4R, and more specifically the relevance condition of A...

  10. Theory of stable allocations II

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2015-01-01

    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. Shapley provided the fundamental theoretical contribution to this field of research, whereas Roth, a professor at the Harvard University in Boston, developed and upgraded these theoretical investigations by applying them to the American market of medical doctors. Namely, their research helps explain the market processes at work, for instance, when doctors are assigned to hospitals, students to schools and human organs for transplant to recipients.

  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. 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....

  13. Recovery of carbon and nutrient pools in a northern forested wetland 11 years after harvesting and site preparation

    Science.gov (United States)

    Carl C. Trettin; Martin F. Jurgensen; Margaret R. Gale; James W. McLaughlin

    2011-01-01

    We measured the change in above- and below-ground carbon and nutrient pools 11 years after the harvesting and site preparation of a histic-mineral soil wetland forest in the Upper Peninsula of Michigan. The original stand of black spruce (Picea mariana), jack pine (Pinus banksiana) and tamarack (Larix laricina) was whole-tree harvested, and three post-harvest...

  14. 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

  15. 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

  16. 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

  17. Belowground induction by Delia radicum or phytohormones affect aboveground herbivore communities on field-grown broccoli

    Directory of Open Access Journals (Sweden)

    Sandra Prisca Pierre

    2013-08-01

    Full Text Available Induced plant defence in response to phytophagous insects is a well described phenomenon. However, so far little is known about the effect of induced plant responses on subsequently colonizing herbivores in the field. Broccoli plants were induced in the belowground compartment using (i infestation by the root-herbivore Delia radicum, (ii root application of jasmonic acid (JA or (iii root application of salicylic acid (SA. The abundance of D. radicum and six aboveground herbivores displaying contrasting levels of host specialisation were surveyed for five weeks. Our study showed that the response of herbivores was found to differ from one another, depending on the herbivore species, its degree of specialisation and the root treatment. The abundance of the root herbivore D. radicum and particularly the number of emerging adults was decreased by both phytohormone treatments, while the number of D. radicum eggs was increased on conspecific infested plants. The root infestation exhibited moderate effects on the aboveground community. The abundance of the aphid Brevicoryne brassicae was strongly increased on D. radicum infested plants, but the other species were not impacted. Root hormone applications exhibited a strong effect on the abundance of specialist foliar herbivores. A higher number of B. brassicae and Pieris brassicae and a lower number of Plutella xylostella were found on JA treated plants. On SA treated plants we observed a decrease of the abundance of B. brassicae, Pi. rapae and P. xylostella. Surprisingly, generalist species, Mamestra brassicae and Myzus persicae were not affected by root induction treatments. Finally, root treatments had no significant effect on either glucosinolate profiles of the heads or on plant quality parameters. These results are discussed from the perspective of below- aboveground interactions and adaptations of phytophagous insects to induced plant responses according to their trophic specialisation level.

  18. 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.

  19. 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.

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

    DEFF Research Database (Denmark)

    Reinsch, Sabine

    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...... 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...

  1. Credit allocation for research institutes

    Science.gov (United States)

    Wang, J.-P.; Guo, Q.; Yang, K.; Han, J.-T.; Liu, J.-G.

    2017-05-01

    It is a challenging work to assess research performance of multiple institutes. Considering that it is unfair to average the credit to the institutes which is in the different order from a paper, in this paper, we present a credit allocation method (CAM) with a weighted order coefficient for multiple institutes. The results for the APS dataset with 18987 institutes show that top-ranked institutes obtained by the CAM method correspond to well-known universities or research labs with high reputation in physics. Moreover, we evaluate the performance of the CAM method when citation links are added or rewired randomly quantified by the Kendall's Tau and Jaccard index. The experimental results indicate that the CAM method has better performance in robustness compared with the total number of citations (TC) method and Shen's method. Finally, we give the first 20 Chinese universities in physics obtained by the CAM method. However, this method is valid for any other branch of sciences, not just for physics. The proposed method also provides universities and policy makers an effective tool to quantify and balance the academic performance of university.

  2. 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.

  3. Resource allocation based on cost efficiency

    DEFF Research Database (Denmark)

    Dehnokhalaji, Akram; Ghiyasi, Mojtaba; Korhonen, Pekka

    2017-01-01

    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...... examples and an empirical illustration are also provided....

  4. 'Unconscionable and irrational' SAPS human resource allocation ...

    African Journals Online (AJOL)

    These areas also suffer among the highest rates of murder and serious violent crime in the province. The allocation of human resources to policing impinges on various constitutional rights. Given the inequity and irrationality apparent in the allocation of police personnel, the Khayelitsha Commission recommended that this ...

  5. Nash Social Welfare in Multiagent Resource Allocation

    NARCIS (Netherlands)

    S. Ramezani (Sara); U. Endriss; E. David; E.H. Gerding (Enrico); D. Sarne; O. Shehory (Onn)

    2010-01-01

    htmlabstractWe 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

  6. 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

  7. 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

  8. Optimal Allocation in Stratified Randomized Response Model

    Directory of Open Access Journals (Sweden)

    Javid Shabbir

    2005-07-01

    Full Text Available A Warner (1965 randomized response model based on stratification is used to determine the allocation of samples. Both linear and log-linear cost functions are discussed under uni and double stratification. It observed that by using a log-linear cost function, one can get better allocations.

  9. 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....

  10. A cost-efficient method to assess carbon stocks in tropical peat soil

    Science.gov (United States)

    Warren, M. W.; Kauffman, J. B.; Murdiyarso, D.; Anshari, G.; Hergoualc'h, K.; Kurnianto, S.; Purbopuspito, J.; Gusmayanti, E.; Afifudin, M.; Rahajoe, J.; Alhamd, L.; Limin, S.; Iswandi, A.

    2012-11-01

    Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m-3; Cd) as a function of bulk density (gC cm-3; Bd), which can be used to rapidly estimate belowground carbon storage using Bd measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (Cd = Bd × 495.14 + 5.41, R2 = 0.93, n = 151) for soils with organic C content > 40%. As organic C content decreases, the relationship between Cd and Bd becomes less predictable as soil texture becomes an important determinant of Cd. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm-3, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation Cd = Bd × 468.76 + 5.82, with R2 = 0.95 and n = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease Cd estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%.

  11. Optimal allocation of reviewers for peer feedback

    DEFF Research Database (Denmark)

    Wind, David Kofoed; Jensen, Ulf Aslak; Jørgensen, Rasmus Malthe

    2017-01-01

    to submissions in such a way that all submissions receive feedback of similar quality and that we are able to significantly outperform simple random allocation of reviewers. Additionally we investigate the effect of pre-allocating reviews in comparison to allocating reviewers live during the review process......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...... 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...

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. Soil Respiration in Tibetan Alpine Grasslands: Belowground Biomass and Soil Moisture, but Not Soil Temperature, Best Explain the Large-Scale Patterns

    Science.gov (United States)

    Geng, Yan; Wang, Yonghui; Yang, Kuo; Wang, Shaopeng; Zeng, Hui; Baumann, Frank; Kuehn, Peter; Scholten, Thomas; He, Jin-Sheng

    2012-01-01

    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 CO2 m−2 s−1, ranging from 0.39 to 12.88 µmol CO2 m−2 s−1, with average daily mean Rs of 2.01 and 5.49 µmol CO2 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. PMID:22509373

  17. Soil respiration in Tibetan alpine grasslands: belowground biomass and soil moisture, but not soil temperature, best explain the large-scale patterns.

    Science.gov (United States)

    Geng, Yan; Wang, Yonghui; Yang, Kuo; Wang, Shaopeng; Zeng, Hui; Baumann, Frank; Kuehn, Peter; Scholten, Thomas; He, Jin-Sheng

    2012-01-01

    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.

  18. 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

  19. The importance of aboveground-belowground interactions on the evolution and maintenance of variation in plant defence traits

    Directory of Open Access Journals (Sweden)

    Moniek evan Geem

    2013-11-01

    Full Text Available 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 compartments. Less is known about genetic variation in plant traits as this applies to an above- belowground framework. For instance, although the field of genetic variation in aboveground plant traits on community-level interactions is well developed, most studies have ignored genetic variation in plant traits – such as defence - that may have evolved in response to pressures from the combined effects of above- and below ground interactions from antagonists and mutualists. Here, we discuss gaps in our understanding of genetic variation in plant- and consumer-related traits as they relate to aboveground and belowground multitrophic interactions. When metabolic resources are limiting, then multiple attack by antagonists in both domains may lead to trade-offs in where these resources are optimally invested. 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.

  20. Modelling Plant and Soil Nitrogen Feedbacks Affecting Forest Carbon Gain at High CO2

    Science.gov (United States)

    McMurtrie, R. E.; Norby, R. J.; Franklin, O.; Pepper, D. A.

    2007-12-01

    Short-term, direct effects of elevated atmospheric CO2 concentrations on plant carbon gain are relatively well understood. There is considerable uncertainty, however, about longer-term effects, which are influenced by various plant and ecosystem feedbacks. A key feedback in terrestrial ecosystems occurs through changes in plant carbon (C) allocation patterns. For instance, if high CO2 were to increase C allocation to roots, then plants may experience positive feedback through improved plant nutrition. A second type of feedback, associated with decomposition of soil-organic matter, may reduce soil-nutrient availability at high CO2. This paper will consider mechanistic models of both feedbacks. Effects of high CO2 on plant C allocation will be investigated using a simple model of forest net primary production (NPP) that incorporates the primary mechanisms of plant carbon and nitrogen (N) balance. The model called MATE (Model Any Terrestrial Ecosystem) includes an equation for annual C balance that depends on light- saturated photosynthetic rate and therefore on [CO2], and an equation for N balance incorporating an expression for N uptake as a function of root mass. The C-N model is applied to a Free Air CO2 Exchange (FACE) experiment at Oak Ridge National Laboratory (ORNL) in Tennessee, USA, where closed-canopy, monoculture stands of the deciduous hardwood sweetgum ( Liquidambar styraciflua) have been growing at [CO2] of 375 and 550 ppm for ten years. Features of this experiment are that the annual NPP response to elevated CO2 has averaged approximately 25% over seven years, but that annual fine-root production has almost doubled on average, with especially large increases in later years of the experiment (Norby et al. 2006). The model provides a simple graphical approach for analysing effects of elevated CO2 and N supply on leaf/root/wood C allocation and productivity. It simulates increases in NPP and fine-root production at the ORNL FACE site that are consistent

  1. 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

  2. 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...

  3. 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...

  4. Carbon Storage in Wetlands and Lakes of the Eastern US

    Science.gov (United States)

    Renik, Byrdie; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

    2001-01-01

    Carbon stored underground may participate in a positive feedback with climate warming, as higher temperatures accelerate decomposition reactions and hence CO2 release. Assessing how below-ground carbon storage varies with modern climate and paleoclimate will advance understanding of this feedback in two ways. First, it will estimate the sensitivity of carbon storage to temperature and precipitation changes. Second, it will help quantify the size of carbon stocks available for the feedback, by indicating how current regional climate differences affect carbon storage. Whereas many studies of below-ground carbon storage concentrate on soils, this investigation focuses on the saturated and primarily organic material stored in wetlands and lake sediments. This study surveys research done on organic sediment depth and organic content at 50-100 sites in the eastern U.S., integrating our own research with the work of others. Storage depth is evaluated for sediments from the past 10,000 years, a date reflected in pollen profiles. Organic content is measured chiefly by loss-on-ignition (101). These variables are compared to characteristics of the sites such as latitude, altitude, and vegetation as well as local climate. Preliminary results suggest a strong relationship between latitude and depth of organic material stored over the last 10,000 years, with more accumulation in the northeastern US than the southeastern US. Linking the percent organic matter to actual carbon content is in progress with wetlands from Black Rock Forest and Alpine Swamp.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil.

    Science.gov (United States)

    Schroth, M H; Eugster, W; Gómez, K E; Gonzalez-Gil, G; Niklaus, P A; Oester, P

    2012-05-01

    Landfills are a major anthropogenic source of the greenhouse gas methane (CH(4)). However, much of the CH(4) produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH(4) fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH(4) ingress (loading) from the waste body at selected locations. Fluxes of CH(4) into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH(4) concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH(4) fluxes and CH(4) loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH(4) oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH(4) emissions from the test section (daily mean up to ∼91,500μmolm(-2)d(-1)), whereas flux-chamber measurements and CH(4) concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH(4) (uptake up to -380μmolm(-2)d(-1)) during the experimental period. Methane concentration profiles also indicated strong variability in CH(4) loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v(max)∼13mmolL(-1)(soil air)h(-1)) at a location with substantial CH(4) loading. Our results provide a basis to assess spatial and temporal variability of CH(4) dynamics in the complex terrain of a landfill-cover soil. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Integrating plant carbon dynamics with mutualism ecology.

    Science.gov (United States)

    Pringle, Elizabeth G

    2016-04-01

    Plants reward microbial and animal mutualists with carbohydrates to obtain nutrients, defense, pollination, and dispersal. Under a fixed carbon budget, plants must allocate carbon to their mutualists at the expense of allocation to growth, reproduction, or storage. Such carbon trade-offs are indirectly expressed when a plant exhibits reduced growth or fecundity in the presence of its mutualist. Because carbon regulates the costs of all plant mutualisms, carbon dynamics are a common platform for integrating these costs in the face of ecological complexity and context dependence. The ecophysiology of whole-plant carbon allocation could thus elucidate the ecology and evolution of plant mutualisms. If mutualisms are costly to plants, then they must be important but frequently underestimated sinks in the terrestrial carbon cycle. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

  11. Detecting Below-Ground Processes, Diversity, and Ecosystem Function in a Savanna Ecosystem Using Spectroscopy Across Different Vegetation Layers

    Science.gov (United States)

    Cavender-Bares, J.; Schweiger, A. K.; Madritch, M. D.; Gamon, J. A.; Hobbie, S. E.; Montgomery, R.; Townsend, P. A.

    2017-12-01

    Above-and below-ground plant traits are important for substrate input to the rhizosphere. The substrate composition of the rhizosphere, in turn, affects the diversity of soil organisms, influences soil biochemistry, and water content, and resource availability for plant growth. This has substantial consequences for ecosystem functions, such as above-ground productivity and stability. Above-ground plant chemical and structural traits can be linked to the characteristics of other plant organs, including roots. Airborne imaging spectroscopy has been successfully used to model and predict chemical and structural traits of the above-ground vegetation. However, remotely sensed images capture, almost exclusively, signals from the top of the canopy, providing limited direct information about understory vegetation. Here, we use a data set collected in a savanna ecosystem consisting of spectral measurements gathered at the leaf, the whole plant, and vegetation canopy level to test for hypothesized linkages between above- and below-ground processes that influence root biomass, soil biochemistry, and the diversity of the soil community. In this environment, consisting of herbaceous vegetation intermixed with shrubs and trees growing at variable densities, we investigate the contribution of different vegetation strata to soil characteristics and test the ability of imaging spectroscopy to detect these in plant communities with contrasting vertical structure.

  12. Below-ground plant–fungus network topology is not congruent with above-ground plant–animal network topology

    Science.gov (United States)

    Toju, Hirokazu; Guimarães, Paulo R.; Olesen, Jens M.; Thompson, John N.

    2015-01-01

    In nature, plants and their pollinating and/or seed-dispersing animals form complex interaction networks. The commonly observed pattern of links between specialists and generalists in these networks has been predicted to promote species coexistence. Plants also build highly species-rich mutualistic networks below ground with root-associated fungi, and the structure of these plant–fungus networks may also affect terrestrial community processes. By compiling high-throughput DNA sequencing data sets of the symbiosis of plants and their root-associated fungi from three localities along a latitudinal gradient, we uncovered the entire network architecture of these interactions under contrasting environmental conditions. Each network included more than 30 plant species and hundreds of mycorrhizal and endophytic fungi belonging to diverse phylogenetic groups. The results were consistent with the notion that processes shaping host-plant specialization of fungal species generate a unique linkage pattern that strongly contrasts with the pattern of above-ground plant–partner networks. Specifically, plant–fungus networks lacked a “nested” architecture, which has been considered to promote species coexistence in plant–partner networks. Rather, the below-ground networks had a conspicuous “antinested” topology. Our findings lead to the working hypothesis that terrestrial plant community dynamics are likely determined by the balance between above-ground and below-ground webs of interspecific interactions. PMID:26601279

  13. Systemic above- and belowground cross talk: hormone-based responses triggered by Heterodera schachtii and shoot herbivores in Arabidopsis thaliana

    Science.gov (United States)

    Kammerhofer, Nina; Egger, Barbara; Dobrev, Petre; Vankova, Radomira; Hofmann, Julia; Schausberger, Peter; Wieczorek, Krzysztof

    2015-01-01

    Above- and belowground plant parts are simultaneously attacked by different pests and pathogens. The host mediates these interactions and physiologically reacts, e.g. with local and systemic alterations of endogenous hormone levels coupled with coordinated transcriptional changes. This in turn affects attractiveness and susceptibility of the plant to subsequent attackers. Here, the model plant Arabidopsis thaliana is used to study stress hormone-based systemic responses triggered by simultaneous root parasitism by the cyst nematode Heterodera schachtii and shoot herbivory by the thrips Frankliniella occidentalis and the spider mite Tetranychus urticae. First, HPLC/MS and quantitative reverse transcriptase PCR are used to show that nematode parasitism strongly affects stress hormone levels and expression of hormone marker genes in shoots. Previous nematode infection is then demonstrated to affect the behavioural and life history performance of both arthropods. While thrips explicitly avoid nematode-infected plants, spider mites prefer them. In addition, the life history performance of T. urticae is significantly enhanced by nematode infection. Finally, systemic changes triggered by shoot-feeding F. occidentalis but not T. urticae are shown to make the roots more attractive for H. schachtii. This work emphasises the importance of above- and belowground signalling and contributes to a better understanding of plant systemic defence mechanisms against plant-parasitic nematodes. PMID:26324462

  14. Drought as a modifier of interaction between adult beech and spruce - impacts on tree water use, C budgets and biotic interactions above- and belowground

    Science.gov (United States)

    Grams, Thorsten

    2017-04-01

    photoassimilates, remained unaffected. The link between photosynthesis and stem cellulose (DBH) was assessed based on natural abundance of delta13C and delta18O. Under drought, mixing of recent photoassimilates with older carbohydrates during phloem transport significantly affected isotopic signatures of transported sucrose, diminishing the impact of drought. A quantitative relationship of this mixing effect (i.e. uncoupling of photosynthetic fractionation at the leaf level and isotopic signatures in stem cellulose) was established. Belowground, a distinct decline in fine root biomass, in particular in spruce, was observed. Along that line, repeated summer drought affected species composition of associated ECM fungi in both species. In particular, changes of ECM exploration types (i.e. contact/short-distance vs. long distance) may be related to C shortage of trees. Along the natural precipitation gradient (PGR), basal area increment of tree stems (DBH) was related to 13C discrimination in tree rings. Carbon isotope signatures proved to be a more sensible indicator of tree responses to drought that BAI. Sensitivity of trees was significantly affected by growth conditions, i.e. growth in mono- vs. mixed culture. Higher drought resistance was displayed by spruce on drier sites (i.e. habituation effect) and, conversely, by beech on moist sites, in particular when grown in mixture with spruce.

  15. 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.

  16. Spatial Allocator for air quality modeling

    Science.gov (United States)

    The Spatial Allocator is a set of tools that helps users manipulate and generate data files related to emissions and air quality modeling without requiring the use of a commercial Geographic Information System.

  17. U.S. Army Recruiter Allocation Model

    National Research Council Canada - National Scie