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Sample records for eastern spruce structural

  1. Characterization of eastern US spruce-fir soils. Book chapter

    SciTech Connect

    Fernandez, I.J.

    1992-01-01

    The spruce-fir forest of the eastern United States encompasses a diverse range of edaphic conditions due to differences in surficial geology, mineralogy, elevation, and climate. This chapter describes the characteristics of soils supporting eastern spruce-fir ecosystems, including soil properties that are important in understanding forest function and the consequences of atmospheric deposition to forested ecosystems. Chapter 1 describes the silvical characteristics of the spruce-fir forest. The Spruce-Fir Research Cooperative included six intensive study sites; five were high-elevation research sites located from western North Carolina to New Hampshire, with one low-elevation site in Maine. Information gained from research at these sites, and other relevant research from these regions, provides the basis for this description of eastern U. S. spruce-fir soils.

  2. AmeriFlux CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce

    SciTech Connect

    Margolis, Hank A.

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce. Site Description - 49.69247° N / 74.34204° W, elevation of 387 mm, 90 - 100 yr old Black Spruce, Jack Pine, feather moss

  3. Impact of eastern dwarf mistletoe (Arceuthobium pusillum) infection on the needles of red spruce (Picea rubens) and white spruce (Picea glauca): oxygen exchange, morphology and composition.

    PubMed

    Reblin, Jaret S; Logan, Barry A; Tissue, David T

    2006-10-01

    Eastern dwarf mistletoe (Arceuthobium pusillum Peck) is a hemiparasitic angiosperm that infects white spruce (Picea glauca (Moench) Voss) and red spruce (P. rubens Sarg.) in northeastern North America. The effects of mistletoe infection differ substantially between white and red spruce, with white spruce suffering greater infection-induced mortality. In the present study, we sought to determine the role that species-specific differences in needle-scale responses to parasitism may play in the observed differences in the effect of infection on host tree health. Based on the measurements made, the most apparent effect of parasitism was a reduction in needle size distal to infections. The magnitude of this reduction was greater in white spruce than in red spruce. Eastern dwarf mistletoe was a sink for host photosynthate in red spruce and white spruce; however, there were no adjustments in needle photosynthetic capacities in either host to accommodate the added sink demands of the parasite. Needle total nonstructural carbohydrate concentrations (TNC) were also unaltered by infection. Red spruce needles had higher TNC concentrations despite having lower overall photosynthetic capacities, suggesting that red spruce may be more sink limited and therefore better able to satisfy the added sink demands of parasitic infection. However, if carbon availability limits the growth of the mistletoe, one may expect that the extent of the parasitic infection would be greater in red spruce. Yet in the field, the extent of infection is generally greater in white spruce. Taken together, these results suggest that dwarf mistletoe may not substantially perturb the carbon balance of either host spruce species and that species-specific differences in needle-scale responses to the parasite cannot explain the contrasting effects of infection on white spruce and red spruce.

  4. Availability of Ectomycorrhizal Fungi to Black Spruce above the Present Treeline in Eastern Labrador

    PubMed Central

    Reithmeier, Laura; Kernaghan, Gavin

    2013-01-01

    Ectomycorrhizal fungi (ECMF) are an important biotic factor in the survival of conifer seedlings under stressful conditions and therefore have the potential to facilitate conifer establishment into alpine and tundra habitats. In order to assess patterns of ectomycorrhizal availability and community structure above treeline, we conducted soil bioassays in which Picea mariana (black spruce) seedlings were grown in field-collected soils under controlled conditions. Soils were collected from distinct alpine habitats, each dominated by a different ectomycorrhizal host shrub: Betula glandulosa, Arctostaphylos alpina or Salix herbacaea. Within each habitat, half of the soils collected contained roots of ectomycorrhizal shrubs (host+) and the other half were free of host plants (host−). Forest and glacial moraine soils were also included for comparison. Fungi forming ectomycorrhizae during the bioassays were identified by DNA sequencing. Our results indicate that ECMF capable of colonizing black spruce are widespread above the current tree line in Eastern Labrador and that the level of available inoculum has a significant influence on the growth of seedlings under controlled conditions. Many of the host− soils possessed appreciable levels of ectomycorrhizal inoculum, likely in the form of spore banks. Inoculum levels in these soils may be influenced by spore production from neighboring soils where ectomycorrhizal shrubs are present. Under predicted temperature increases, ectomycorrhizal inoculum in soils with host shrubs as well as in nearby soils without host shrubs have the potential to facilitate conifer establishment above the present tree line. PMID:24204858

  5. Paradigms in Eastern Spruce Budworm (Lepidoptera: Tortricidae) Population Ecology: A Century of Debate.

    PubMed

    Pureswaran, Deepa S; Johns, Rob; Heard, Stephen B; Quiring, Dan

    2016-09-01

    Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Multiple Equilibria, with warm weather conditions releasing low-density populations from the regulatory control of natural enemies. Dispersal from outbreak foci, or "epicenters," was seen as causing widespread outbreaks that eventually collapsed following resource depletion. However, in the 1980s, following the re-analysis of data from the 1940s outbreak in New Brunswick, this interpretation was challenged. The alternative Oscillatory Hypothesis proposed that budworm population dynamics were governed by a second-order density-dependent process, with oscillations being driven by natural enemy-victim interactions. Under this hypothesis, weather and resource availability contribute to secondary fluctuations around the main oscillation, and weather and moth dispersal serve to synchronize population cycles regionally. Intensive, independent population studies during the peak and declining phases of the 1980s outbreak supported the principal tenet of the Oscillatory Hypothesis, but concluded that host plant quality played a more important role than this hypothesis proposed. More recent research on the early phase of spruce budworm cycles suggests that mate-finding and natural-enemy-driven Allee effects in low-density populations might be overcome by immigration of moths, which can facilitate the onset of outbreaks. Even more recent research has supported components of all three hypotheses attempting to explain spruce budworm dynamics. In the midst of a new rising outbreak (2006-present), we discuss the evolution of debates surrounding these hypotheses from a historic perspective

  6. Paradigms in Eastern Spruce Budworm (Lepidoptera: Tortricidae) Population Ecology: A Century of Debate.

    PubMed

    Pureswaran, Deepa S; Johns, Rob; Heard, Stephen B; Quiring, Dan

    2016-12-01

    Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Multiple Equilibria, with warm weather conditions releasing low-density populations from the regulatory control of natural enemies. Dispersal from outbreak foci, or "epicenters," was seen as causing widespread outbreaks that eventually collapsed following resource depletion. However, in the 1980s, following the re-analysis of data from the 1940s outbreak in New Brunswick, this interpretation was challenged. The alternative Oscillatory Hypothesis proposed that budworm population dynamics were governed by a second-order density-dependent process, with oscillations being driven by natural enemy-victim interactions. Under this hypothesis, weather and resource availability contribute to secondary fluctuations around the main oscillation, and weather and moth dispersal serve to synchronize population cycles regionally. Intensive, independent population studies during the peak and declining phases of the 1980s outbreak supported the principal tenet of the Oscillatory Hypothesis, but concluded that host plant quality played a more important role than this hypothesis proposed. More recent research on the early phase of spruce budworm cycles suggests that mate-finding and natural-enemy-driven Allee effects in low-density populations might be overcome by immigration of moths, which can facilitate the onset of outbreaks. Even more recent research has supported components of all three hypotheses attempting to explain spruce budworm dynamics. In the midst of a new rising outbreak (2006-present), we discuss the evolution of debates surrounding these hypotheses from a historic perspective

  7. AmeriFlux CA-Qcu Quebec - Eastern Boreal, Black Spruce/Jack Pine Cutover

    DOE Data Explorer

    Margolis, Hank A. [Université Laval

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-Qcu Quebec - Eastern Boreal, Black Spruce/Jack Pine Cutover. Site Description - The ground is gently rolling with a weak slope (<5%). In mesic areas (designated as well to moderately well drained areas, according to the Canadian System of Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1983)), the soil is a ferro-humic to humic podzol covered by an organic layer having an average depth of 26 cm (Fig. 1). In humid areas, the soil is organic (imperfectly to poorly drained) with an average organic layer of 125 cm. Mesic areas accounted for approximately 75% of the total surface area of the footprint and humid areas accounted for 25%. Full-time continuous measurements eneded in 2011. Intermittent measurements are on-going as resources permit.

  8. Detection of single and mixed covert baculovirus infections in eastern spruce budworm, Choristoneura fumiferana populations.

    PubMed

    Kemp, Elizabeth M; Woodward, David T; Cory, Jenny S

    2011-07-01

    We surveyed for covert baculovirus infections in the eastern spruce budworm, Choristoneura fumiferana (Clemens) and compared the prevalence of virus detected in a laboratory and a field population. DNA was extracted from budworm adults and then PCR with degenerate primers was used to identify individuals carrying baculovirus DNA. Multiplex PCR was then applied to the positive samples to distinguish between the multiple baculovirus types that could potentially be found in C. fumiferana populations. Covert infections were found in both the laboratory and the field population of C. fumiferana, although the frequency of infection and the composition of viruses found were very different. Overall 28% of insects from the laboratory population were positive for baculovirus DNA. Individual adults supported both single and mixed covert infections with CfMNPV plus CfDEFNPV, CfDEFNPV plus a GV and mixtures of all three viruses together. However, the majority of insects supported single virus infections, and surprisingly this virus was CfDEFNPV, a virus that is reported not to have per os activity in C. fumiferana larvae. Insects from field populations showed a very different pattern; 70.5% of individuals were baculovirus positive and all of these were positive for CfDEFNPV only.

  9. Total and pyrogenic carbon stocks in black spruce forest floors from eastern Canada

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, Laure; Quideau, Sylvie; MacKenzie, M. Derek; Munson, Alison; Boiffin, Juliette; Bernard, Guy; Wasylishen, Roderick

    2016-04-01

    In boreal forests, pyrogenic carbon (PyC), a by-product of recurrent wildfires, is an important component of the global soil C pool, although precise assessment of boreal PyC stock is scarce. In this study including 14 fire sites spreading over 600 km in the Quebec province, our aim was to better estimate total C stock and PyC stock in forest floors of Eastern Canada boreal forests. We also investigated the environmental conditions controlling the stocks and characterized the composition of the various forest floor layers. We analyzed the forest floor samples that were collected from mesic black spruce sites recently affected by fire (3-5 years) using elemental analysis and solid state 13C nuclear magnetic resonance (NMR) spectroscopy. PyC content was further estimated using a molecular mixing model on the 13C NMR data. Total C stock in forest floors averaged 5.7 ± 2.9 kg C/m2 and PyC stock 0.6 ± 0.3 kg C/m2. Total C stock was under control of the position in the landscape, with a greater accumulation of organic material on northern aspects and lower slope positions. In addition, total stock was significantly higher in spruce-dominated forest floors than in stands where jack pine was dominant. The PyC stock was significantly related to the atomic H/C ratio (R2 = 0.84) of the different organic layers. 13C NMR spectroscopy revealed a large increase in aromatic carbon in the deepest forest floor layer (humified H horizon) at the organic-mineral soil interface. The majority of the PyC stock was located in this horizon and had been formed during past high severity fires rather than during the most recent fire event. Conversely, the superficial "fresh" PyC layer, produced by early-season wildfires in 2005-2007, had NMR spectra fairly similar to unburned forest floors and comparatively low PyC stocks.

  10. Soil-mediated effects of atmospheric deposition on eastern US spruce-fir forests. Book chapter

    SciTech Connect

    Johnson, D.W.; Fernandez, I.J.

    1992-01-01

    The coincident observation of Waldsterben in Germany and red spruce decline in the northeastern U.S. has naturally led to some speculation that similar mechanisms may be involved. In the German situation, soil-mediated hypotheses played (and still play) a major role; namely, soil acidification and aluminum toxicity and base cation deficiencies. In the red spruce case, there has been much concern that cation deficiencies and/or aluminum toxicity may also play a major role. The purpose of this chapter is to: (1) review some of the basic properties of soils, nutrition, and nutrient cycling in spruce-fir and fir ecosystems, both in the polluted and in the relatively unpolluted regions of the U.S. and Canada, and (2) to evaluate several soil acidity-related hypotheses for red spruce decline.

  11. Impact of eastern dwarf mistletoe (Arceuthobium pusillum) on host white spruce (Picea glauca) development, growth and performance across multiple scales.

    PubMed

    Logan, Barry A; Reblin, Jaret S; Zonana, David M; Dunlavey, Ryan F; Hricko, Carolyn R; Hall, Adam W; Schmiege, Stephanie C; Butschek, Ross A; Duran, Kristy L; Emery, R J Neil; Kurepin, Leonid V; Lewis, James D; Pharis, Richard P; Phillips, Nathan G; Tissue, David T

    2013-04-01

    Infection by eastern dwarf mistletoe (Arceuthobium pusillum) modifies needle and branch morphology and hastens white spruce (Picea glauca) mortality. We examined potential causal mechanisms and assessed the impacts of infection-induced alterations to host development and performance across scales ranging from needle hormone contents to bole expansion. Needles on infected branches (IBs) possessed higher total cytokinin (CK) and lower abscisic acid contents than needles on uninfected branches (UBs). IBs exhibited greater xylem growth than same-aged UBs, which is consistent with the promotive effect of CKs on vascular differentiation and organ sink strength. Elevated CK content may also explain the dense secondary and tertiary branching observed at the site of infection, i.e. the formation of 'witches' brooms' with significantly lower light capture efficiencies. Observed hormone perturbations were consistent with higher rates of transpiration, lower water use efficiencies (WUEs) and more negative needle carbon isotope ratios observed for IBs. Observed reductions in needle size allowed IBs to compensate for reduced hydraulic conductivity. Severe infections resulted in dramatically decreased diameter growth of the bole. It seems likely that the modifications to host hormone contents by eastern dwarf mistletoe infection led white spruce trees to dedicate a disproportionate fraction of their photoassimilate and other resources to self-shaded branches with low WUE. This would have decreased the potential for fixed carbon accumulation, generating a decline in the whole-tree resource pool. As mistletoe infections grew in size and the number of IBs increased, this burden was manifested as increasingly greater reductions in bole growth.

  12. BVOC emission in Norway spruce: the effect of stand structure, high temperature and ozone levels.

    NASA Astrophysics Data System (ADS)

    Pallozzi, Emanuele; Guidolotti, Gabriele; Večeřová, Kristýna; Esposito, Raffaela; Lusini, Ilaria; Juráň, Stanislav; Urban, Otmar; Calfapietra, Carlo

    2015-04-01

    Norway spruce (Picea abies L.) is a widely distributed conifer species in the boreal zone and mountain areas of central Europe and is a moderate emitter of volatile organic compounds (BVOC). Although the vaporization and diffusion processes from resin ducts were generally considered to be the main processes for monoterpene emissions in conifers, recently it has been showed that a significant portion (up to one third) of monoterpene emissions of Norway spruce can originate from novel biosynthesis, thus depending on photosynthetic processes. For this reason, both biosynthesis and emission are strongly influenced by the environment and the stand structure. They increase with both increasing light and temperature during the warmer periods, although those are the periods with the higher ozone concentration that usually act as an inhibitor of both assimilation and isoprenoids synthesis and emission. On the other hand, stand structure can play an important role, because the photosynthetic capacity is influenced by temperature and light conditions through the canopy. In order to assess the effects of stand structure, temperature and ozone on isoprenoids emission of Norway spruce we carried out field and laboratory experiments. In the experimental field campaigns we measured: assimilation and BVOC emission from needles of sun and shade layers within the canopy of the spruce forest present at the Bily Kriz experimental research site (Moravian-Silesian Beskydy Mountains, 49° 33' N, 18° 32' E, NE of Czech Republic, 908 m a.s.l.). Moreover in the same layers we measured continuously concentration of BVOCs in the air using a PTR-TOF-MS. In laboratory we analyzed the effects of short-term exposure to high temperature and high ozone concentrations on branches of spruce trees collected at the Bily Kriz experimental research site. Preliminary results show that in Norway spruce both stand structure and environmental conditions influenced the gas exchange and BVOC emission rates

  13. Response of aluminum solubility to elevated nitrification in soil of a red spruce stand in eastern Maine

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.

    1997-01-01

    Elevated concentrations of soluble Al can impair tree growth and be toxic to aquatic biota, but effects of acidic deposition on Al solubility in forest soils are only partially understood because of complex interactions with H+ and organic matter. We therefore evaluated Al solubility in two red spruce stands in eastern Maine, one of which received dry (NH4)2SO4 at a rate of 1800 equiv ha-1 yr-1 during 19891995. Samples of soil (Spodosol Oa and Bh horizons) and soil solution were collected on five dates from 1992 to 1995. The treatment elevated nitrification, causing an increase in acid input that led to inorganic Al concentrations of greater than 60 ??mol L-1 in both the Oa and Bh horizons. Solubility of Al was also lower in the Bh horizon of the treated stand than in the reference stand, a response related to higher DOC concentrations in the treated stand. Concentrations of CuCl2 and pyrophosphate-extractable Al were higher in the Oa horizon of the treated watershed than the reference stand, a result of accelerated weathering of mineral particles caused by lower solution pH in the treated stand (3.47) than in the reference stand (3.69). Dissolved Al concentrations in these soils are the result of complex mechanisms through which mineral matter, organic matter, and pH interact to control Al solubility; mechanisms that are not incorporated in current Al solubility models.

  14. SABATH methyltransferases from white spruce (Picea glauca): gene cloning, functional characterization and structural analysis.

    PubMed

    Zhao, Nan; Boyle, Brian; Duval, Isabelle; Ferrer, Jean-Luc; Lin, Hong; Seguin, Armand; MacKay, John; Chen, Feng

    2009-07-01

    Known members of the plant SABATH family of methyltransferases have important biological functions by methylating hormones, signalling molecules and other metabolites. While all previously characterized SABATH genes were isolated from angiosperms, in this article, we report on the isolation and functional characterization of SABATH genes from white spruce (Picea glauca [Moench] Voss), a gymnosperm. Through EST database search, three genes that encode proteins significantly homologous to known SABATH proteins were identified from white spruce. They were named PgSABATH1, PgSABATH2 and PgSABATH3, respectively. Full length cDNAs of these three genes were cloned and expressed in Escherichia coli. The E. coli-expressed recombinant proteins were tested for methyltransferase activity with a large number of compounds. While no activity was detected for PgSABATH2 and PgSABATH3, PgSABATH1 displayed the highest level of catalytic activity with indole-3-acetic acid (IAA). PgSABATH1 was, therefore, renamed PgIAMT1. Under steady-state conditions, PgIAMT1 exhibited apparent Km values of 18.2 microM for IAA. Homology-based structural modelling of PgIAMT1 revealed that the active site of PgIAMT1 is highly similar to other characterized IAMTs from angiosperms. PgIAMT1 showed expression in multiple tissues, with the highest level of expression detected in embryonic tissues. During somatic embryo maturation, a significant reduction in PgIAMT1 transcript levels was observed when developing cotyledons become apparent which is indicative of mature embryos. The biological roles of white spruce SABATH genes, especially those of PgIAMT1, and the evolution of the SABATH family are discussed.

  15. Structure and Carbon Distribution of Well- and Poorly-Drained Black Spruce Fire Chronosequences

    NASA Astrophysics Data System (ADS)

    Wang, C.; Bond-Lamberty, B.; Gower, S. T.

    2002-12-01

    The objectives of this study were to: (1) examine structure changes along a boreal black spruce (Picea mariana (Mill.) BSP) fire chronosequence in northern Manitoba, Canada; (2) quantify temporal dynamics in C content across the chronosequence; and (3) compare the C distribution for these stands on contrasting soil drainages. The experimental design was a well-drained (dry) and poorly-drained (wet) black spruce fire chronosequences comprised of seven stands that burned between 1998 and 1870. Tree species diversity was greater in the younger stands, and by 71 years after fire black spruce comprised >88% and 83% of total basal area for the dry and wet stands, respectively. Feather moss replaced sphagnum during succession in the dry stands, whereas there were no clear patterns in the wet chronosequence. Total vegetation C content (aboveground + belowground) increased with forest succession, ranging from 1.3 to 83.3 t C ha-1 for the dry stands and 0.6 to 37.4 t C ha-1 for the wet stands. Mean annual aboveground C accumulation rates (Δ CA) peaked in the 71- and 36-year-old dry and wet stands, respectively. Overstory and live moss C contents increased with stand age. The total root : shoot ratio was fairly consistent (0.235 +/- 0.046) after 37 years following fire. The basal area, vegetation C content, and Δ CA were significantly greater (α = 0.05) in the dry than wet stands, but the C contents in bryophyte and forest floor were significantly less in the dry stands. Our results emphasize the need to incorporate disturbance and soil drainage in large-scale boreal forest C models.

  16. Investigation of changes in structure and thermodynamic of spruce budworm antifreeze protein under subfreezing temperature

    NASA Astrophysics Data System (ADS)

    Nguyen, Hung; Le, Ly

    2017-01-01

    The aim of this theoretical work is to investigate of the changes in structure and thermodynamics of spruce budworm antifreeze protein (sbAFP) at low temperatures by using molecular dynamics simulation. The aqueous solution will form ice crystal network under the vaguely hexagonal shape at low temperature and fully represented the characteristics of hydrophobic interaction. Like ice crystal network, the cyclohexane region (including cyclohexane molecules) have enough of the characteristics of hydrophobic interaction. Therefore, in this research the cyclohexane region will be used as a representation of ice crystal network to investigate the interactions of sbAFP and ice crystal network at low temperature. The activity of sbAFP in subfreezing environment, therefore, can be clearly observed via the changes of the hydrophobic (cyclohexane region) and hydrophilic (water region) interactions. The obtained results from total energies, hydrogen bond lifetime correlation C(t), radial distribution function, mean square deviation and snapshots of sbAFP complexes indicated that sbAFP has some special changes in structure and interaction with water and cyclohexane regions at 278 K, as being transition temperature point of water molecules in sbAFP complex at low temperatures, which is more structured and support the experimental observation that the sbAFP complex becomes more rigid as the temperature is lowered.

  17. Investigation of changes in structure and thermodynamic of spruce budworm antifreeze protein under subfreezing temperature

    PubMed Central

    Nguyen, Hung; Le, Ly

    2017-01-01

    The aim of this theoretical work is to investigate of the changes in structure and thermodynamics of spruce budworm antifreeze protein (sbAFP) at low temperatures by using molecular dynamics simulation. The aqueous solution will form ice crystal network under the vaguely hexagonal shape at low temperature and fully represented the characteristics of hydrophobic interaction. Like ice crystal network, the cyclohexane region (including cyclohexane molecules) have enough of the characteristics of hydrophobic interaction. Therefore, in this research the cyclohexane region will be used as a representation of ice crystal network to investigate the interactions of sbAFP and ice crystal network at low temperature. The activity of sbAFP in subfreezing environment, therefore, can be clearly observed via the changes of the hydrophobic (cyclohexane region) and hydrophilic (water region) interactions. The obtained results from total energies, hydrogen bond lifetime correlation C(t), radial distribution function, mean square deviation and snapshots of sbAFP complexes indicated that sbAFP has some special changes in structure and interaction with water and cyclohexane regions at 278 K, as being transition temperature point of water molecules in sbAFP complex at low temperatures, which is more structured and support the experimental observation that the sbAFP complex becomes more rigid as the temperature is lowered. PMID:28106056

  18. The effects of partial cutting on stand structure and growth of western hemlock-Sitka spruce stands in southeast Alaska

    USGS Publications Warehouse

    Deal, R.L.; Tappeiner, J.C.

    2002-01-01

    The effects of partial cutting on species composition, new and residual-tree cohorts, tree size distribution, and tree growth was evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12-96 years ago, when 16-96% of the former stand basal area was removed. Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effects on tree species composition. The establishment of new-tree cohorts was positively related to the proportion of basal-area cut. The current stand basal area, tree species composition, and stand growth were significantly related to trees left after harvest (p < 0.001). Trees that were 20-80 cm dbh at the time of cutting had the greatest tree-diameter and basal-area growth and contributed the most to stand growth. Diameter growth of Sitka spruce and western hemlock was similar, and the proportion of stand basal-area growth between species was consistent for different cutting intensities. Concerns about changing tree species composition, lack of spruce regeneration, and greatly reduced stand growth and vigor with partial cuts were largely unsubstantiated. Silvicultural systems based on partial cutting can provide rapidly growing trees for timber production while maintaining complex stand structures with mixtures of spruce and hemlock trees similar to oldgrowth stands.

  19. Hoverfly (syrphidae) communities respond to varying structural retention after harvesting in canadian peatland black spruce forests.

    PubMed

    Deans, A M; Smith, S M; Malcolm, J R; Crins, W J; Bellocq, M I

    2007-04-01

    Variable retention harvesting (VRH), in which trees are removed at variable intensity and spatial configuration across the landscape, retains greater forest structural heterogeneity than traditional clear-cut harvesting and is being recommended as an alternative for sustainable management of the boreal forest. Little is known about its effects on forest fauna; thus, we studied the influence of one type of VRH (harvesting with advanced regeneration [HARP]) on the Syrphidae (Diptera) community in northern Ontario forests of peatland black spruce (Picea mariana). We examined the effects of varying structural retention (from unharvested through partial retention to clear-cut) on syrphid species richness and abundance, and abundance of functional assemblages. Greater species richness and population abundances were found generally in harvested than in unharvested forests. Overall species richness and the abundance of four species (Platycheirus rosarum, Toxomerus marginatus, Xylota annulifera, and X. tuberculata) and larval predators were all higher in both clear-cut sites and those with structural retention than in unharvested sites. Similarly, overall species richness and the abundance of nine species were higher in clear-cut than in unharvested sites. Species responses are discussed in an ecological context. Differences among the levels of forest retention harvesting were relatively minor compared with those of the clear-cut and unharvested area, suggesting that local habitat characteristics may play a more important role in determining the syrphid community than the landscape configuration. However, a landscape level effect was evident, suggesting that syrphids may be useful in reflecting changes in stand structure at the landscape scale.

  20. Diurnal changes in the dielectric properties and water status of eastern hemlock and red spruce from Howland, ME

    NASA Technical Reports Server (NTRS)

    Salas, W. A.; Ranson, K. J.; Rock, B. N.; Moss, D. M.

    1991-01-01

    The diurnal characteristics of microwave dielectric properties and water potential of two conifer species were investigated in July and September, 1990. P-band and C-band radial dielectric profiles of hemlock and red spruce, as well as hemlock diurnal water potential and dielectric profiles, are presented. The resulting radial dielectric profiles matched the regions of the functional sapwood (water transport component of the active xylem) in both species such that the sapwood was characterized by a higher dielectric than the bark and heartwood tissues. This is probably due to characteristic differences in the water content of each tissue. As the hemlocks progressed through their diurnal water potential pattern, the dielectric profile remained static until mid-afternoon. As the tension in the water column relaxed (2 to 3 bars) the dielectric constant decreased by 30 to 40 percent. There are several possible explanations for this phenomenon, and these may relate to the dependency of the dielectric measurements on temperature, salinity, and volumetric water content.

  1. Hydraulic and mechanical properties of young Norway spruce clones related to growth and wood structure.

    PubMed

    Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo

    2007-08-01

    Stem segments of eight five-year-old Norway spruce (Picea abies (L.) Karst.) clones differing in growth characteristics were tested for maximum specific hydraulic conductivity (k(s100)), vulnerability to cavitation and behavior under mechanical stress. The vulnerability of the clones to cavitation was assessed by measuring the applied air pressure required to cause 12 and 50% loss of conductivity (Psi(12), Psi(50)) and the percent loss of conductivity at 4 MPa applied air pressure (PLC(4MPa)). The bending strength and stiffness and the axial compression strength and stiffness of the same stem segments were measured to characterize wood mechanical properties. Growth ring width, wood density, latewood percentage, lumen diameter, cell wall thickness, tracheid length and pit dimensions of earlywood cells, spiral grain and microfibril angles were examined to identify structure-function relationships. High k(s100) was strongly and positively related to spiral grain angle, which corresponded positively to tracheid length and pit dimensions. Spiral grain may reduce flow resistance of the bordered pits of the first earlywood tracheids, which are characterized by rounded tips and an equal distribution of pits along the entire length. Wood density was unrelated to hydraulic vulnerability parameters. Traits associated with higher hydraulic vulnerability were long tracheids, high latewood percentage and thick earlywood cell walls. The positive relationship between earlywood cell wall thickness and vulnerability to cavitation suggest that air seeding through the margo of bordered pits may occur in earlywood. There was a positive phenotypic and genotypic relationship between k(s100) and PLC(4MPa), and both parameters were positively related to tree growth rate. Variability in mechanical properties depended mostly on wood density, but also on the amount of compression wood. Accordingly, hydraulic conductivity and mechanical strength or stiffness showed no tradeoff.

  2. Effects of warming on the structure and function of a boreal black spruce forest

    SciTech Connect

    Stith T.Gower

    2010-03-03

    A strong argument can be made that there is a greater need to study the effect of warming on boreal forests more than on any other terrestrial biome. Boreal forests, the second largest forest biome, are predicted to experience the greatest warming of any forest biome in the world, but a process-based understanding of how warming will affect the structure and function of this economically and ecologically important forest biome is lacking. The effects of warming on species composition, canopy structure and biogeochemical cycles are likely to be complex; elucidating the underlying mechanisms will require long-term whole-ecosystem manipulation to capture all the complex feedbacks (Shaver et al. 2000, Rustad et al. 2001, Stromgren 2001). The DOE Program for Ecosystem Research funded a three year project (2002-2005) to use replicated heated chambers on soil warming plots in northern Manitoba to examine the direct effects of whole-ecosystem warming. We are nearing completion of our first growing season of measurements (fall 2004). In spite of the unforeseen difficulty of installing the heating cable, our heating and irrigation systems worked extremely well, maintaining environmental conditions within 5-10% of the specified design 99% of the time. Preliminary data from these systems, all designed and built by our laboratory at the University of Wisconsin, support our overall hypothesis that warming will increase the carbon sink strength of upland boreal black spruce forests. I request an additional three years of funding to continue addressing the original objectives: (1) Examine the effect of warming on phenology of overstory, understory and bryophyte strata. Sap flux systems and dendrometer bands, monitored by data loggers, will be used to quantify changes in phenology and water use. (2) Quantify the effects of warming on nitrogen and water use by overstory, understory and bryophytes. (3) Compare effects of warming on autotrophic respiration and above- and belowground

  3. Elicitor-Induced Spruce Stress Lignin (Structural Similarity to Early Developmental Lignins).

    PubMed Central

    Lange, B. M.; Lapierre, C.; Sandermann, H.

    1995-01-01

    Suspension cultures of Picea abies (L.) Karst released polymeric material into the culture medium when treated with an elicitor preparation from the spruce needle pathogen Rhizosphaera kalkhoffii. The presence of lignin (about 35%, w/w) was demonstrated by phloroglucinol/HCI reactivity and quantitation with thioglycolic acid. Carbohydrate (about 14%, w/w) and protein (about 32%, w/w) were also detected. Amino acid analysis revealed that hydroxyproline and proline predominated. Thioacidolysis and subsequent Raney nickel desulfurization allowed the analysis of lignin-building units and interunit bonds. Compared with spruce wood lignin, an approximately 20-fold higher relative amount of p-hydroxyphenyl units was determined. A high content of p-hydroxyphenyl units is typical for certain developmental lignins, such as conifer compression wood and middle lamella lignins, as well as all induced cell culture lignins so far analyzed. Cross-linkages of the pinoresinol type ([beta]-[beta]) in the excreted cell culture lignin were markedly increased, whereas [beta]-1 interunit linkages were decreased relative to spruce wood lignin. The amount and nature of cross-linkages were shown to be intermediate between those in wood lignin and in enzymatically prepared lignins. In summary, the elicitor-induced stress lignin was excreted as a lignin-extensin complex that closely resembled early developmental lignins. PMID:12228544

  4. Can nutrient limitations explain low and declining white spruce growth near the Arctic treeline in the eastern Brooks Range, Alaska?

    NASA Astrophysics Data System (ADS)

    Ellison, S.; Sullivan, P. F.

    2014-12-01

    The position of the Arctic treeline is of critical importance for global carbon cycling and surface energy budgets. However, controls on tree growth at treeline remain uncertain. In the Alaskan Brooks Range, 20th century warming has caused varying growth responses among treeline trees, with trees in the west responding positively, while trees in the east have responded negatively. The prevailing explanation of this trend ascribes the negative growth response to warming-induced drought stress in the eastern Brooks Range. However, recent measurements of carbon isotope discrimination in tree rings, xylem sap flow and needle gas exchange suggest that drought stress cannot explain these regional growth declines. Additionally, evidence from the western Brooks Range suggests that nutrient availability, rather than drought stress, may be the proximate control on tree growth. In this study, we investigated the hypothesis that low and declining growth of eastern Brooks Range trees is due to low and declining soil nutrient availability, which may continue to decrease with climate change as soils become drier and microbial activity declines. We compared microclimate, tree performance, and a wide range of proxies for soil nutrient availability in four watersheds along a west-east transect in the Brooks Range during the growing seasons of 2013 and 2014. We hypothesized that soil nutrient availability would track closely with the strong west-east precipitation gradient, with higher rainfall and greater soil nutrient availability in the western Brooks Range. We expected to find that soil water contents in the west are near optimum for nitrogen mineralization, while those in the east are below optimum. Needle nitrogen concentration, net photosynthesis, branch extension growth, and growth in the main stem are expected to decline with the hypothesized decrease in soil nutrient availability. The results of our study will elucidate the current controls on growth of trees near the

  5. Subsurface structure of the eastern Arkoma basin

    SciTech Connect

    Vanarsdale, R.B. ); Schweig, E.S. III )

    1990-07-01

    Analysis of 425 km of seismic reflection data in the eastern Arkoma basin reveals a structure and history quite different from those previously reported for the Arkoma basin. The eastern Arkoma basin has three structural styles that formed in the following chronological order: deep, steep normal faults; shallow listric normal faults; and thrust faults. The origin of the structural styles and the Paleozoic history of the eastern Arkoma basin may be summarized as follows. Late Proterozoic or Early Cambrian rifting was followed by deposition of Cambrian through Upper Mississippian strata on a passive plate margin. The Mississippian-Pennsylvanian boundary marks a time of major down-to-the-south normal faulting with coincident folding of the footwall blocks and truncation of the faulted and folded terrain by a pre-Morrowan (Mississippian-Pennsylvanian) unconformity. The unconformity slopes southward and steepens locally across the erosionally truncated footwall blocks. During the Pennsylvanian, down-to-the-south listric normal faults cut the Atokan and Morrowan sections and merged with, but did not displace, the steeper segments of the sub-Morrowan unconformity. Surface folds north of the Ross Creek thrust are rollover anticlines overlying these listric normal faults. Major deformation in the eastern Arkoma basin terminated with emplacement of the Ross Creek thrust in the Late Pennsylvanian. 4 figs., 1 tab.

  6. Edaphic Selection Pressures as Drivers of Contrasting White Spruce Ectomycorrhizal Fungal Community Structure and Diversity in the Canadian Boreal Forest of Abitibi-Témiscamingue Region

    PubMed Central

    Nadeau, Martin B.; P. Khasa, Damase

    2016-01-01

    Little is known about edaphic selection pressures as drivers of contrasting white spruce ectomycorrhizal fungal community structure and diversity in the Canadian boreal forest. We hypothesized that community composition differs among the four sites sampled–nursery, mining site, forest edge, and natural forest. Ectomycorrhizal (ECM) fungal community structure and diversity was studied at the four locations with soil fertility gradient through morpho-molecular and phylogenetic analyses in relationships with rhizospheric soil chemical properties. 41 different species were identified. Mining site had a significantly different species composition than the surrounding environments. Soil pH and percentage of roots colonized by ECM fungi increased while soil P, N, Fe, C, K, Mg, Al, Ca, and Na contents declined across the soil fertility gradient: nursery → natural forest → forest edge → mining site. Contrary to the preference of acid soils by ECM fungi, a few ecologically adapted to high pH, poor soil chemical fertility, and low organic matter content colonize white spruce roots on the non-acidogenic mining site, allowing natural regeneration of white spruce seedlings. Other ECM fungi are adapted to high fertigation level of commercial nursery. This study clearly shows the contrasting difference in white spruce ectomycorrhizal fungal community structure and diversity driven by edaphic selection pressures. PMID:27835688

  7. Crustal Structure in Central-Eastern Greenland

    NASA Astrophysics Data System (ADS)

    Shulgin, A.; Thybo, H.

    2013-12-01

    We present the seismic structure in the interior of Greenland based on the first measurements by the seismic refraction/wide angle reflection method. Previous seismic surveys have only been carried out offshore and near the coast of Greenland, where the crustal structure is affected by oceanic break-up and may not be representative of the interior of the island. Acquisition of geophysical data onshore Greenland is logistically complicated by the presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The EW-trending profile extends 310 km inland from the approximate edge of the stable ice cap near Scoresby Sund across the centre of the ice cap. The planned extension of the profile by use of OBSs and air gun shooting in Scoresbysund Fjord to the east coast of Greenland was unfortunately cancelled, because navigation was prevented by ice drift. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 100 kg at 35-85 m depth in individual boreholes. Two-dimensional velocity model based on forward ray tracing and tomography modelling shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western part to 40 km in the eastern part of the profile. Earlier studies show that crustal thickness further decreases eastward to ca. 30 km below the fjord system, but details of the changes are unknown. Relatively high lower crustal velocities (Vp 6.8 - 7.3) in the western part of the TopoGreenland profile may indicate past collision tectonics or may be related or to the passage of the Iceland mantle plume. The origin of the pronounced circum-Atlantic mountain ranges in Norway and eastern Greenland, which have

  8. Geologic and structural map of eastern Asia

    SciTech Connect

    Letouzey, J.; Sage, L.

    1986-07-01

    A synthesis of the onshore and offshore geologic data of eastern Asia, prepared by the Institut Francais du Petrole (IFP), has allowed the construction of geologic and structural maps for this region. These maps include three color sheets (scale = 1:2.5 million) and three plates of geologic and structural cross sections. Located between lat. 4/sup 0/ and 35/sup 0/N, and long. 106/sup 0/ and 132/sup 0/E, the maps cover the following geographic areas: East and South China Sea, Sulu Sea, West Philippine basin and onshore neighboring terrains, Kyushu and Ryukyu Islands, the China margin, Taiwan Island, Vietnam, North West Borneo, and the Philippines. The maps synthesize seismic interpretations, oil well data, geologic work in south Japan, Taiwan, Borneo, and the Philippines, and recent data published between 1976 and 1985. Twenty-four geologic cross sections (scale = 1:1.25 million, vertical exaggeration x 6) intersect ocean margins, important basins, and the different structural domains. They are based on seismic profiles, well data, and available onshore and offshore geologic data. These cross sections show basement composition and structures, different tectonic and sedimentary domains, and the structure and thickness of different sedimentary deposits (such as age, unconformities, and geologic structures). Maps and cross sections will be published in early 1987.

  9. Occurrence of Cystosporogenes sp. (Protozoa, Microsporidia) in a multi-species insect production facility and its elimination from a colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae).

    PubMed

    van Frankenhuyzen, Kees; Ebling, Peter; McCron, Bob; Ladd, Tim; Gauthier, Debbie; Vossbrinck, Charles

    2004-09-01

    We have isolated a microsporidium from a laboratory colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae). Light and electron microscopic investigations showed that gross pathology and ultrastructure of our isolate are similar to those described for Cystosporogenes legeri from the European grape vine moth, Lobesia botrana. Comparative phylogenetic analysis of the small subunit rDNA using maximum likelihood, maximum parsimony, and neighbour joining distance methods revealed perfect homology with the C. legeri sequence. The microsporidian was infectious to other Choristoneura species, as well as Malacosoma disstria, Lymantria dispar, and Lambdina fiscellaria. Incubation of infected egg masses at 41 degrees C for 20 min followed by 30 min in 33% formaldehyde did not reduce disease incidence in larval offspring. Exposure of one or two generations to fumagillin at 6000 ppm or higher eliminated infection in adult moths, but also reduced colony fitness. A clean colony was established by conducting individual matings and selecting disease-free offspring.

  10. Specific impacts of beech and Norway spruce on the structure and diversity of the rhizosphere and soil microbial communities

    PubMed Central

    Uroz, S.; Oger, P.; Tisserand, E.; Cébron, A.; Turpault, M.-P.; Buée, M.; De Boer, W.; Leveau, J. H. J.; Frey-Klett, P.

    2016-01-01

    The impacts of plant species on the microbial communities and physico-chemical characteristics of soil are well documented for many herbs, grasses and legumes but much less so for tree species. Here, we investigate by rRNA and ITS amplicon sequencing the diversity of microorganisms from the three domains of life (Archaea, Bacteria and Eukaryota:Fungi) in soil samples taken from the forest experimental site of Breuil-Chenue (France). We discovered significant differences in the abundance, composition and structure of the microbial communities associated with two phylogenetically distant tree species of the same age, deciduous European beech (Fagus sylvatica) and coniferous Norway spruce (Picea abies Karst), planted in the same soil. Our results suggest a significant effect of tree species on soil microbiota though in different ways for each of the three microbial groups. Fungal and archaeal community structures and compositions are mainly determined according to tree species, whereas bacterial communities differ to a great degree between rhizosphere and bulk soils, regardless of the tree species. These results were confirmed by quantitative PCR, which revealed significant enrichment of specific bacterial genera, such as Burkholderia and Collimonas, known for their ability to weather minerals within the tree root vicinity. PMID:27302652

  11. Red spruce dynamics in an old southern Appalachian forest

    USGS Publications Warehouse

    Busing, R.T.

    2004-01-01

    By the late 1980s the composition and structure of forest stands in the southern Appalachian spruce-fir zone were altered by insect infestations to Fraser fir. The response of red spruce, the sole remaining coniferous forest dominant, to this disturbance was followed over twenty years (1983-2003) in an old spruce-fir forest at Mt. Collins, Great Smoky Mountains National Park. Although diameter growth of canopy red spruce (>30 cm dbh) at six plot sites was considerable (mean 10-yr increment 2.1 cm; 1993-2003), red spruce mortality increased sharply (mean 4% yr-1; 1993-2003). Wind-related mortality of canopy red spruce was substantial after the loss of Fraser fir from the canopy circa 1985 (>70% of the dead spruce had broken or uprooted boles; 1983-2003). Wind damage to red spruce was observed at most plot sites, but it was most pronounced on exposed topographic positions, where canopy gap expansion was extensive. The elevated mortality of red spruce at Mt. Collins was not associated with reduced diameter growth. Altered canopy structure has left large red spruce vulnerable to high winds. With the loss of canopy fir and the subsequent increase in mortality of canopy spruce, total live basal area has declined to about half of its pre-disturbance level.

  12. High Resolution Velocity Structure in Eastern Turkey

    SciTech Connect

    Pasyanos, M; Gok, R; Zor, E; Walter, W

    2004-09-03

    We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver functions using iterative time-domain deconvolution technique and surface wave group velocity dispersion curves between 10-100 sec. We are making surface wave dispersion measurements at the ETSE stations and have incorporated them into a regional group velocity model. Preliminary results indicate a strong trend in the long period group velocity in the northeast. This indicates slow upper mantle velocities in the region consistent with Pn, Sn and receiver function results. We started with both the 1-D model that is obtained with the 12 tones dam explosion shot data recorded by ETSE network and the existing receiver function

  13. High Resolution Velocity Structure in Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Pasyanos, M. E.; Gok, R.; Zor, E.; Walter, W. R.

    2004-12-01

    We investigate the crust and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet, forming a complex tectonic regime. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provide a unique opportunity for studying the high resolution velocity structure of the region. Zor et al. (2003) found an average 46 km thick crust in the Anatolian plateau using a six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver functions alone, however, may result in an apparent depth-velocity trade-off [Ammon et al., 1990]. In order to improve upon this velocity model, we have combined the receiver functions with surface wave data using the joint inversion method of Julia et al. (2000). In this technique, the two sets of observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. The receiver functions are calculated using an iterative time-domain deconvolution technique. We also consider azimuthal changes in the receiver functions and have stacked them into different groups accordingly. We are improving our surface wave model by making Love and Rayleigh dispersion measurements at the ETSE stations and incorporating them into a regional group velocity model for periods between 10 and 100 seconds. Preliminary results indicate a strong trend in the long period group velocities toward the northeast, indicating slow upper mantle velocities in the area consistent with Pn, Sn and receiver function results. Starting models used for the joint inversions include both a 1-D model from a 12-ton dam shot recorded by ETSE [Gurbuz et al., 2004] and

  14. Identifying the pollen of an extinct spruce species in the Late Quaternary sediments of the Tunica Hills region, south-eastern United States

    USGS Publications Warehouse

    Luke Mander,; Jacklyn Rodriguez,; Pietra G. Mueller,; Jackson, Stephen T.; Surangi W. Punyasena,

    2014-01-01

    Late Quaternary fluvial deposits in the Tunica Hills region of Louisiana and Mississippi are rich in spruce macrofossils of the extinct species Picea critchfieldii, the one recognized plant extinction of the Late Quaternary. However, the morphology of P. critchfieldii pollen is unknown, presenting a barrier to the interpretation of pollen spectra from the last glacial of North America. To address this issue, we undertook a morphometric study of Picea pollen from Tunica Hills. Morphometric data, together with qualitative observations of pollen morphology using Apotome fluorescence microscopy, indicate that Picea pollen from Tunica Hills is morphologically distinct from the pollen of P. glauca, P. mariana and P. rubens. Measurements of grain length, corpus width and corpus height indicate that Picea pollen from Tunica Hills is larger than the pollen of P. mariana and P. rubens, and is slightly larger than P. glauca pollen. We argue that the morphologically distinctive Tunica Hills Picea pollen was probably produced by the extinct spruce species P. critchfieldii. These morphological differences could be used to identify P. critchfieldii in existing and newly collected pollen records, which would refine its paleoecologic and biogeographic history and clarify the nature and timing of its extinction in the Late Quaternary.

  15. A high-resolution reference genetic map positioning 8.8 K genes for the conifer white spruce: structural genomics implications and correspondence with physical distance.

    PubMed

    Pavy, Nathalie; Lamothe, Manuel; Pelgas, Betty; Gagnon, France; Birol, Inanç; Bohlmann, Joerg; Mackay, John; Isabel, Nathalie; Bousquet, Jean

    2017-04-01

    Over the last decade, extensive genetic and genomic resources have been developed for the conifer white spruce (Picea glauca, Pinaceae), which has one of the largest plant genomes (20 Gbp). Draft genome sequences of white spruce and other conifers have recently been produced, but dense genetic maps are needed to comprehend genome macrostructure, delineate regions involved in quantitative traits, complement functional genomic investigations, and assist the assembly of fragmented genomic sequences. A greatly expanded P. glauca composite linkage map was generated from a set of 1976 full-sib progeny, with the positioning of 8793 expressed genes. Regions with significant low or high gene density were identified. Gene family members tended to be mapped on the same chromosomes, with tandemly arrayed genes significantly biased towards specific functional classes. The map was integrated with transcriptome data surveyed across eight tissues. In total, 69 clusters of co-expressed and co-localising genes were identified. A high level of synteny was found with pine genetic maps, which should facilitate the transfer of structural information in the Pinaceae. Although the current white spruce genome sequence remains highly fragmented, dozens of scaffolds encompassing more than one mapped gene were identified. From these, the relationship between genetic and physical distances was examined and the genome-wide recombination rate was found to be much smaller than most estimates reported for angiosperm genomes. This gene linkage map shall assist the large-scale assembly of the next-generation white spruce genome sequence and provide a reference resource for the conifer genomics community.

  16. Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

    PubMed Central

    Bače, Radek; Svoboda, Miroslav; Janda, Pavel; Morrissey, Robert C.; Wild, Jan; Clear, Jennifer L.; Čada, Vojtěch; Donato, Daniel C.

    2015-01-01

    Background Severe canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand. Methods Two stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover. Results Post-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand’s height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights. Conclusion These findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural

  17. Eastern Boundary Effects on General Circulation Structure

    NASA Technical Reports Server (NTRS)

    Dewar, William K.

    1997-01-01

    My NASA proposal included plans to examine the dynamics of the eastern oceanic boundary, with a view towards those processes important to the interior. Several relevant tasks have been completed and either have appeared or will appear soon in the refereed literature.

  18. Genetic structure of Sakhalin spruce (Picea glehnii) in northern Japan and adjacent regions revealed by nuclear microsatellites and mitochondrial gene sequences.

    PubMed

    Aizawa, Mineaki; Yoshimaru, Hiroshi; Takahashi, Makoto; Kawahara, Takayuki; Sugita, Hisashi; Saito, Hideyuki; Sabirov, Renat N

    2015-01-01

    The genetic structure of Sakhalin spruce (Picea glehnii) was studied across the natural range of the species, including two small isolated populations in south Sakhalin and Hayachine, by using six microsatellite loci and maternally inherited mitochondrial gene sequences. We also analyzed P. jezoensis, a sympatric spruce in the range. Genetic diversity of P. glehnii was higher in central Hokkaido and the lowest in the Hayachine. Bayesian clustering and principal coordinate analysis by using the microsatellites indicated that the Hayachine was clearly distinct from other populations, implying that it had undergone strong genetic drift since the last glacial period. P. glehnii harbored four mitochondrial haplotypes, two of which were shared with P. jezoensis. One of the two was observed without geographical concentration, suggesting its derivation from ancestral polymorphism. Another was observed in south Sakhalin and in P. jezoensis across Sakhalin. The Bayesian clustering--by using four microsatellite loci, including P. jezoensis populations--indicated unambiguous species delimitation, but with possible admixture of P. jezoensis genes into P. glehnii in south Sakhalin, where P. glehnii is abundantly overwhelmed by P. jezoensis; this might explain the occurrence of introgression of the haplotype of P. jezoensis into P. glehnii.

  19. Ambient seismic noise tomography and structure of eastern North America

    NASA Astrophysics Data System (ADS)

    Liang, Chuntao; Langston, Charles A.

    2008-03-01

    The time derivative of cross-correlation functions (CCF) of ambient noise fields recorded by two stations can be approximated as the Green's Function (GF) between the stations. The CCFs are thus used as Peudo-GFs (dominated by surface waves) to invert for group velocity structure in eastern North America. Stations from two regional networks deployed to monitor the New Madrid Seismic Zone and eastern Tennessee seismic zone, together with stations of the US National Seismic Network, greatly improve tomographic ray coverage. The short period (T = 5 s) group velocity map shows strong correlations with the depth to Precambrian basement. Many subtle local structures can be clearly identified from the velocity map, including the Ozark uplift, Cincinnati Arch, Nashville Dome and the Blue Ridge province of the Appalachians showing relatively high group velocity. The long period (T = 15 s) group velocity map shows strong correlations with regional geology. Ancient rift basins, such as the Mid-Continent Rift (MCR) system, the Reelfoot rift, the Oklahoma Aulacogen and the Eastern Continent Rift, are associated with low velocity belts along their rift axes. We also find that all major seismic zones in eastern North America, such as the New Madrid seismic zone, Eastern Tennessee seismic zone as well as Ouachita Orogen seismic zone, are approximately located at transition zones separating velocity highs and lows. This observation suggests that those seismic zones may reflect the reactivation of ancient faults associated with continental rift and collision zones.

  20. Structural changes in the vascular bundles of light-exposed and shaded spruce needles suffering from Mg deficiency and ozone pollution.

    PubMed

    Boxler-Baldoma, Carmen; Lütz, Cornelius; Heumann, Hans-Günther; Siefermann-Harms, Dorothea

    2006-02-01

    The correlation between structural changes of the vascular bundles and needle yellowing was examined for needles of damaged spruce (Picea abies (L.) Karst.) growing at a Mg-deficient and ozone polluted mountain site in the Central Black Forest (840m a.s.l.). In the previous year's sun-exposed needles, the following sequence of events was observed: (1) rapid needle yellowing, (2) hypertrophy and anomalous divisions of cambium cells, (3) phloem collapse, and, (4) production of atypical xylem tracheids. Under defined shade (reduction of the photosynthetically active photon flux density of the ambient light by 85-90%), the needles remained green, while the phloem collapsed completely within the first 6 weeks of shading; subsequently, a reversal of the collapse was observed. Under both light conditions, the content of Mg not bound to chlorophyll (Mg(free)) was in the range of 0.1 mg g(-1) needle dry matter, and hardly changed throughout the investigation period. After Mg fertilization, the Mg(free) level of the previous year's needles increased to 0.2 mg g(-1) dry matter, the light-exposed needles remained green, and the vascular bundles developed no anomalies. The data show that the rapid needle yellowing of ozone-exposed Mg-deficient needles did not depend on the collapse of the phloem. Mg deficiency played a key role in the development of anomalous vascular bundles under light, and also appears to explain the transient changes in sieve cell structure under shade. The role of Mg deficiency, rather than ozone pollution, in the damage of the sieve cells was confirmed in a long-term ozone exposure experiment with young clonal spruce growing under defined conditions.

  1. Structure, production and resource use in some old-growth spruce/fir forests in the front range of the Rocky Mountains, USA

    USGS Publications Warehouse

    Binkley, D.; Olsson, U.; Rochelle, R.; Stohlgren, T.; Nikolov, N.

    2003-01-01

    Old-growth forests of Engelmann spruce (Picea engelmannii Parry ex. Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) dominate much of the landscape of the Rocky Mountains. We characterized the structure, biomass and production of 18 old-growth (200-450-year-old) spruce/fir forests in Rocky Mountain National Park, Colorado, as well as the stand-level supply and use of light and nitrogen. Stands were chosen to span a broad range of elevation, aspect, and topography. Aboveground tree biomass in these old-growth forests averaged 253 Mg/ha (range 130-488 Mg/ha), with aboveground net primary production of 3700 kg ha-1 yr-1 (range from 2700 to 5200 kg ha-1 yr-1). Within stands, trees >35 cm in diameter accounted for 70% of aboveground biomass, but trees <35 cm contributed 70% of the production of woody biomass. Differences in slope and aspect among sites resulted in a range of incoming light from 58 to 74 TJ ha-1 yr-1, and tree canopies intercepted an average of 71% of incoming light (range 50-90%). Aboveground net primary production (ANPP) of trees did not relate to the supply of light or N, but ANPP correlated strongly with the amount of light and N used (r2 = 0.45-0.54, P < 0.01). Uptake of 1 kg of N was associated with about 260 kg of ANPP, and one TJ of intercepted shortwave radiation produced about 78 kg of ANPP. Across these old-growth stands, stands with greater biomass showed higher rates of both ANPP and resource use; variation in aboveground biomass was associated with 24% of the variation in N use (P = 0.04), 44% of the light use (P = 0.003), and 45% of the ANPP (P = 0.002). ?? 2002 Elsevier Science B.V. All rights reserved.

  2. Full Genome of Phialocephala scopiformis DAOMC 229536, a Fungal Endophyte of Spruce Producing the Potent Anti-Insectan Compound Rugulosin

    PubMed Central

    Frasz, Samantha L.; Seifert, Keith A.; Miller, J. David; Mondo, Stephen J.; LaButti, Kurt; Lipzen, Anna; Dockter, Rhyan B.; Kennedy, Megan C.; Grigoriev, Igor V.; Spatafora, Joseph W.

    2016-01-01

    We present the full genome of Phialocephala scopiformis DAOMC 229536 (Helotiales, Ascomycota), a foliar endophyte of white spruce from eastern Quebec. DAOMC 229536 produces the anti-insectan compound rugulosin, which inhibits a devastating forestry pest, the spruce budworm. This genome will enable fungal genotyping and host-endophyte evolutionary genomics in inoculated trees. PMID:26950333

  3. New interpretation of the deep mantle structure beneath eastern China

    NASA Astrophysics Data System (ADS)

    Ma, Pengfei; Liu, Shaofeng; Lin, Chengfa; Yao, Xiang

    2016-04-01

    Recent study of high resolution seismic tomography presents a large mass of high velocity abnormality beneath eastern China near the phase change depth, expanding more than 1600km-wide in East-west cross-section across the North China plate. This structure high is generally believed to be the subducted slab of Pacific plate beneath the Eurasia continent, while its origin and dynamic effect on the Cenozoic tectonic evolution of eastern China remain to be controversial. We developed a subduction-driven geodynamic mantle convection model that honors a set of global plate reconstruction data since 230Ma to help understand the formation and evolution of mantle structure beneath eastern China. The assimilation of plate kinematics, continuous evolving plate margin, asymmetric subduction zone, and paleo seafloor age data enables the spatial and temporal consistency between the geologic data and the mantle convection model, and guarantees the conservation of the buoyancy flux across the lithosphere and subducted slabs. Our model achieved a first order approximation between predictions and the observed data. Interestingly, the model suggests that the slab material stagnated above discontinuity didn't form until 15Ma, much later than previous expected, and the fast abnormality in the mid-mantle further west in the tomographic image is interpreted to be the remnants of the Mesozoic Izanagi subduction. Moreover, detailed analysis suggests that the accelerated subduction of Philippine Sea plate beneath Eurasia plate along the Ryukyu Trench and Nankai Trough since 15Ma may largely contribute to extending feature above 670km discontinuity. The long distance expansion of the slab material in the East-west direction may be an illusion caused by the approximate spatial perpendicularity between the cross-section and the subduction direction of the Philippine Sea plate. Our model emphasizes the necessity of the re-examination on the geophysical observation and its tectonic and

  4. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions.

    PubMed

    Landry, Mathieu; Comeau, André M; Derome, Nicolas; Cusson, Michel; Levesque, Roger C

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota.

  5. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions

    PubMed Central

    Landry, Mathieu; Comeau, André M.; Derome, Nicolas; Cusson, Michel; Levesque, Roger C.

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota. PMID:26636571

  6. Cell Structural Changes in the Needles of Norway Spruce Exposed to Long‐term Ozone and Drought

    PubMed Central

    KIVIMÄENPÄÄ, MINNA; SUTINEN, SIRKKA; KARLSSON, PER ERIK; SELLDÉN, GUN

    2003-01-01

    Effects of ozone and/or drought on Norway spruce needles were studied using light microscopy and electron microscopy. Saplings were exposed to ozone in open‐top chambers during 1992–1995 and also to drought in the late summers of 1993–1995. Samples from current and previous year needles were collected five times during 1995. Ozone increased the numbers of peroxisomes and mitochondria, which suggests that defence mechanisms against oxidative stress were active. The results from peroxisomes suggest that the oxidative stress was more pronounced in the upper side of the needles, and those from mitochondria that defence was more active in the younger needle generation. Possibly due to the good nitrogen status and the active defence, no ozone‐specific chloroplast alterations were seen. At the end of the season, older needles from ozone treatments had smaller central vacuoles compared with other needles. Cytoplasmic vacuoles around the nucleus were increased by ozone in the beginning of the experiment, and did not increase towards the end of the season as in the controls. These results from vacuoles may indicate that ozone affected the osmotic properties of the cells. Decreased number and underdevelopment of sclerenchyma cells and proliferation of tonoplast were related to nutrient imbalance, which was enhanced by drought. Larger vascular cylinders and more effective starch accumulation before and after the drought periods compensated for the reduced water status. Numbers of peroxisomes and mitochondria were increased in the drought‐exposed needles before the onset of drought treatments of the study year, i.e. these changes were memory effects. Interactions between ozone and drought were few. PMID:14576076

  7. Investigation of upper crustal structure beneath eastern Java

    NASA Astrophysics Data System (ADS)

    Martha, Agustya Adi; Widiyantoro, Sri; Cummnins, Phil; Saygin, Erdinc; Masturyono

    2016-05-01

    The complexity of geology structure in eastern Java causes this region has many potential resources as much as the disasters. Therefore, the East Java province represents an interesting area to be explored, especially regarding its upper crustal structure. To investigate this structure, we employ the Ambient Noise Tomography (ANT) method. We have used seismic waveform data from 25 Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 26 portable seismographs installed for 2 to 8 weeks. Inter-station cross-correlation produces more than 800 Rayleigh wave components, which depict the structure beneath eastern Java. Based on the checkerboard resolution test, we found that the optimal grid size is 0.25ox0.25o. Our inversion results for the periods of 1 to 10 s indicate a good agreement with geological and Bouguer anomaly maps. Rembang high depression, most of the southern mountains zone, the northern part of Rembang zone and the central part of the Madura Island, the area of high gravity anomaly and areas dominated with igneous rocks are associated with high velocity zones. On the other hand, Kendeng zone and most of the basin in the Rembang zone are associated with low velocity zones.

  8. Structure and shale gas production patterns from eastern Kentucky field

    SciTech Connect

    Shumaker, R.C.

    1987-09-01

    Computer-derived subsurface structure, isopach, and gas-flow maps, based on 4000 drillers logs, have been generated for eastern Kentucky under a project sponsored by the Gas Research Institute. Structure maps show low-relief flextures related to basement structure. Some structures have been mapped at the surface, others have not. Highest final open-flow (fof) of shale gas from wells in Martin County follow a structural low between (basement) anticlines. From there, elevated gas flows (fof) extend westward along the Warfield monocline to Floyd County where the high flow (fof) trend extends southward along the Floyd County channel. In Knott County, the number of wells with high gas flow (fof) decreases abruptly. The center of highest gas flow (fof) in Floyd County spreads eastward to Pike County, forming a triangular shaped area of high production (fof). The center of highest gas flow (fof) is in an area where possible (basement) structure trends intersect and where low-relief surface folds (probably detached structure) were mapped and shown on the 1922 version of the Floyd County structure map. Modern regional maps, based on geophysical logs from widely spaced wells, do not define the low-relief structures that have been useful in predicting gas flow trends. Detailed maps based on drillers logs can be misleading unless carefully edited. Comparative analysis of high gas flows (fof) and 10-year cumulative production figures in a small area confirms that there is a relationship between gas flow (fof) values and long-term cumulative production.

  9. Profiling functions of ectomycorrhizal diversity and root structuring in seedlings of Norway spruce (Picea abies) with fast- and slow-growing phenotypes.

    PubMed

    Velmala, Sannakajsa M; Rajala, Tiina; Heinonsalo, Jussi; Taylor, Andy F S; Pennanen, Taina

    2014-01-01

    We studied the role of taxonomical and functional ectomycorrhizal (ECM) fungal diversity in root formation and nutrient uptake by Norway spruce (Picea abies) seedlings with fast- and slow-growing phenotypes. Seedlings were grown with an increasing ECM fungal diversity gradient from one to four species and sampled before aboveground growth differences between the two phenotypes were apparent. ECM fungal colonization patterns were determined and functional diversity was assayed via measurements of potential enzyme activities of eight exoenzymes probably involved in nutrient mobilization. Phenotypes did not vary in their receptiveness to different ECM fungal species. However, seedlings of slow-growing phenotypes had higher fine-root density and thus more condensed root systems than fast-growing seedlings, but the potential enzyme activities of ectomycorrhizas did not differ qualitatively or quantitatively. ECM species richness increased host nutrient acquisition potential by diversifying the exoenzyme palette. Needle nitrogen content correlated positively with high chitinase activity of ectomycorrhizas. Rather than fast- and slow-growing phenotypes exhibiting differing receptiveness to ECM fungi, our results suggest that distinctions in fine-root structuring and in the belowground growth strategy already apparent at early stages of seedling development may explain later growth differences between fast- and slow-growing families.

  10. Lagged cumulative spruce budworm defoliation affects the risk of fire ignition in Ontario, Canada.

    PubMed

    James, Patrick M A; Robert, Louis-Etienne; Wotton, B Mike; Martell, David L; Fleming, Richard A

    2017-03-01

    Detailed understanding of forest disturbance interactions is needed for effective forecasting, modelling, and management. Insect outbreaks are a significant forest disturbance that alters forest structure as well as the distribution and connectivity of combustible fuels at broad spatial scales. The effect of insect outbreaks on fire activity is an important but contentious issue with significant policy consequences. The eastern spruce budworm (Choristoneura fumiferana) is a native defoliating insect in eastern North America whose periodic outbreaks create large patches of dead fir and spruce trees. Of particular concern to fire and forest managers is whether these patches represent an increased fire risk, if so, for how long, and how the relationship between defoliation and fire risk varies through space and time. Previous work suggests a temporary increase in flammability in budworm-killed forests, but regional and seasonal variability in these relationships has not been examined. Using an extensive database on historical lightning-caused fire ignitions and spruce budworm defoliation between 1963 and 2000, we assess the relative importance of cumulative defoliation and fire weather on the probability of ignition in Ontario, Canada. We modeled fire ignition using a generalized additive logistic regression model that accounts for temporal autocorrelation in fire weather. We compared two ecoregions in eastern Ontario (Abitibi Plains) and western Ontario (Lake of the Woods) that differ in terms of climate, geomorphology, and forest composition. We found that defoliation has the potential to both increase and decrease the probability of ignition depending on the time scale, ecoregion, and season examined. Most importantly, we found that lagged spruce budworm defoliation (8-10 yr) increases the risk of fire ignition whereas recent defoliation (1 yr) can decrease this risk. We also found that historical defoliation has a greater influence on ignition risk during the

  11. SPRUCE experiment data infrastructure

    NASA Astrophysics Data System (ADS)

    Krassovski, M.; Hanson, P. J.; Boden, T.; Riggs, J.; Nettles, W. R.; Hook, L. A.

    2013-12-01

    The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL), USA has provided scientific data management support for the US Department of Energy and international climate change science since 1982. Among the many data activities CDIAC performs are design and implementation of the data systems. One current example is the data system and network for SPRUCE experiment. The SPRUCE experiment (http://mnspruce.ornl.gov) is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. Experimental work in the 8.1-ha S1 bog will be a climate change manipulation focusing on the combined responses to multiple levels of warming at ambient or elevated CO2 (eCO2) levels. The experiment provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, the cycling and release of CO2 and CH4 to the atmosphere). The manipulation will evaluate the response of the existing biological communities to a range of warming levels from ambient to +9°C, provided via large, modified open-top chambers. The ambient and +9°C warming treatments will also be conducted at eCO2 (in the range of 800 to 900 ppm). Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. SPRUCE provides wide range continuous and discrete measurements. To successfully manage SPRUCE data flow

  12. Climate-Induced Mortality of Spruce Stands in Belarus

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-01-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  13. Climate-induced mortality of spruce stands in Belarus

    NASA Astrophysics Data System (ADS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-12-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  14. Vertical fine structure observations in the eastern equatorial Pacific

    SciTech Connect

    Hayes, S.P.

    1981-11-20

    Measurements of vertical displacement and horizontal velocity finestructure near the equator at 110/sup 0/W in the eastern Pacific Ocean are reported. Profiles were scaled to a constant Bruent-Vaeisaelae frequency ocean (N/sub 0/ = 1 cph) in accordance with a WKBJ approximation. A total of 57 CTD casts between 3/sup 0/N and 3/sup 0/S taken during five cruises in 1979 were analyzed. Results show an equatorial enhancement of vertical displacement is similar variance for vertical wavelengths longer than 50 sdbar (stretched decibars). This enhancement is similar to that which has been reported at 125/sup 0/W and 179/sup 0/E. Difference between locations can be accounted for by the observed temporal variability at 110/sup 0/W. Coherence between vertical displacement profiles separated in time by dealys of 2 hours to 120 hour indicate that the high wave number structures were largely associated with time scales of 4 days and less. Meridionally, vertical structures longer than 300 sdbar were coherent within 50 km of the equator. We interpret this vertical displacement fine structure enhancement as high wave number equatorially trapped inertial-gravity waves. The velocity fine structure measurements in July 1979 also indicate equatorially enhanced horizontal kinetic energy for vertical wave lengths longer than 100 sdbar. The velocity structures persisted over the 56 hour of measurement and appeared to have longer time scales than the vertical displacements. Meridional energy measurement and appeared to have longer time scales than the vertical displacements. Meridional energy exceeded zonal energy; however, the two components were coherent. We interpret these velocity structures as inertial-gravity waves which were produced off the equator and are propagating through the equatorial region.

  15. Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles

    USGS Publications Warehouse

    Matsuoka, S.M.; Handel, C.M.; Ruthrauff, D.R.

    2001-01-01

    We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

  16. 1. 20472009 SPRUCE ST. RUNS FROM LEFT TO RIGHT. SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. 2047-2009 SPRUCE ST. RUNS FROM LEFT TO RIGHT. SOUTH (FRONT) FACADES. VIEW LOOKING NORTHEAST - Spruce Street Area Study, 2009-2045 Spruce Street (Houses), Spruce Street, north side, Philadelphia, Philadelphia County, PA

  17. Structural Model of the Tucupita Field, Eastern Venezuela Basin

    NASA Astrophysics Data System (ADS)

    Arteaga, L. A.

    2013-05-01

    The Tucupita Field has an area of 73,51 Km2, is located between the states of Monagas and Delta Amacuro, geologically is located at the greater Temblador area in the Eastern Venezuela Basin, where the Oficina Formation's sands represent the main hydrocarbons reservoirs. From the results of the seismic reprocessing realized by Fusion Petroleum Technologies, Inc., the structural model of this field was done as initial step to the geocellular model of the Oficina-40 Reservoir, which was defined as a Faulted Relay Ramp, where the normal faults are dominant with NE-SW orientation Introduction The Tucupita Field is a mature oilfield at the greater Temblador area, however most of the wells were completed in the upper sands, therefore the main study is focused in the geological characterization of the Oficina-40 Reservoir's lower sands, starting by the structural model Previous Studies 1. Proyecto Tucupita 3D The seismic data of the Tucupita Field were adquired in 1996 by Western Atlas of Venezuela for the Benton Vinccler Company. The UTM coordinates of the wells used in this project, have been taken to make this geological model 2. Soporte Geofísico Integrado The seismic project Tucupita was processed by Fusion Petroleum Technologies Inc., in Houston and consisted of reprocessing and pre-stack migration in time (PSTM) and pre-stack migration in depth (PSDM), this data belong to the Petrodelta Company Based on the regional stratigraphy, were validated the "picks" to make the structural sections to support research with hard data. After, it proceeded to interpret the structural style of the field from the seismic amplitude cube. Then, it was done the faults modelling and the stratigraphic horizons to carry out the geocellular model Three structural sections were realized, which was interpreted like a faulted monocline, whose peak is located southward, where justly the wells are located. The contact oil-water was interpreted to -5648'. Echelon faults were interpreted in a

  18. Fire severity unaffected by spruce beetle outbreak in spruce-fir forests in southwestern Colorado.

    PubMed

    Andrus, Robert A; Veblen, Thomas T; Harvey, Brian J; Hart, Sarah J

    2016-04-01

    Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB; Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennis Kirby) infestation on subsequent fire severity in subalpine Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests. In Colorado, the annual area infested by spruce beetle outbreaks is rapidly rising, while MPB outbreaks are subsiding; therefore understanding this relationship is of growing importance. We collected extensive field data in subalpine forests in the eastern San Juan Mountains, southwestern Colorado, USA, to investigate whether a gray-stage (< 5 yr from outbreak to time of fire) spruce beetle infestation affected fire severity. Contrary to the expectation that bark beetle infestation alters subsequent fire severity, correlation and multivariate generalized linear regression analysis revealed no influence of pre-fire spruce beetle severity on nearly all field or remotely sensed measurements of fire severity. Findings were consistent across moderate and extreme burning conditions. In comparison to severity of the pre-fire beetle outbreak, we found that topography, pre-outbreak basal area, and weather conditions exerted a stronger effect on fire severity. Our finding that beetle infestation did not alter fire severity is consistent with previous retrospective studies examining fire activity following other bark beetle outbreaks and reiterates the overriding influence of climate that creates conditions conducive to large, high-severity fires in the subalpine zone of Colorado

  19. Evolution of volcanism around the eastern sector of Mt. Etna, inland and offshore, in the structural framework of eastern Sicily

    NASA Astrophysics Data System (ADS)

    Patané, Giuseppe; Agostino, Ivan; La Delfa, Santo; Leonardi, Riccardo

    2009-04-01

    The authors highlight a new perspective to understanding the volcanism in the Mt. Etna eastern sector, inland and offshore, based on original studies of the sea floor off the Ionian coast of Etna by means of various direct surveying methods (underwater explorations) and indirect ones (bathymetric reconstructions using echosounders). They also propose a new interpretation of geophysical, geochemical and structural surveys carried out over the last two decades. Results show that eastern Etnean sector's volcanism extends as far as the Ionian Sea, to a maximum distance from the coast of probably about 20 km. In their opinion, the absence of outcropping apparatuses in the lower eastern flank of Etna is due to these apparatuses being buried by a large detritic formation ("Chiancone") due to the dismantling of the Ancient Alkaline Centres (AAC) localised to the West. The authors consider the structures highlighted by the study of the Digital Elevation Model (DEM) of the Ionian sea floor and by the Multibeam analysis (Marani et al., 2004. From Seafloor to Deep Mantle: Architecture of the Tyrrhenian Backarc Basin, vol. 44. Mem. Descr. Carta Geol. Ital. pp. 1-2) to be of a volcanic nature. This hypothesis opens up a new field of study within the evolution of the eastern Etnean edge's volcanism, inland and offshore, in the last 500 Ky and would further confirm the eruptive axes migration from East to West.

  20. Growth declines in red spruce

    SciTech Connect

    McLaughlin, S.B. ); Adams, H.S. )

    1987-10-01

    In this letter, the authors take issue with Zedaker, Hyink, and Smith who have indicated that observed red spruce growth declines can be expected based on growth trends for even-aged stands of red spruce as documented in Meyer (1929). Recently, an examination was made of stand stocking levels at 750 sites where red spruce were cored and neither the rate of growth decline nor the extent of mortality were found to be related to stand stocking levels or previous disturbance history. The authors conclude that the Meyer data do not represent an appropriate model for stand dynamics of old-growth, high-elevation stands and no not adequately explain the growth declines observed at many of those sites.

  1. Structure and tectonic setting of the eastern Tehachapi Range, California

    SciTech Connect

    Wood, D.J.; Saleeby, J.B.; Silver, L.T. . Division of Geological and Planetary Sciences)

    1993-04-01

    In the easternmost Tehachapi mountains a moderately SE dipping fault zone with an irregular trace juxtaposes high grade ductilely deformed footwall gneisses against a cataclastically deformed granitic hanging wall complex from Tehachapi Valley to the Garlock FZ. The fault zone exhibits evidence of both ductile and brittle deformation. Moderately SE plunging stretching lineations and sense of shear indicators in the footwall suggest normal displacement and the sole of the hanging wall consists of a chloritic breccia. The footwall consists of garnet-amphibolite grade orthogneiss, paragneiss, and marble, locally protomylonitic, folded into presently SW vergent isoclinal folds with a penetrative, NW trending, moderately NE dipping foliation. This gneiss complex hosts a 0.2 to 0.8 km wide, NW tending, shallow NE dipping ductile shear zone, called here the eastern Tehachapi shear zone (ETSZ). The ETSZ appears to post-date much of the isoclinal folding in the gneisses. The ETSZ is inferred to continue north of Tehachapi valley (Ross, 1989) where it steepens and swings to a more northerly trend into the Lake Isabella region where it has been called the proto-Kern Canyon fault zone. A post ETSZ deformation refolded the gneisses into open, upright folds with moderately NE plunging axes. Juxtaposition of the gneisses and the cataclastically deformed granitic hanging wall rocks occurred during and/or after this post ETSZ folding event. In the structurally lowest levels of the gneiss complex exposed along the Garlock fault, quartz diorite orthogneiss becomes increasingly deformed downward with an NE striking, moderately NW dipping mylonitic fabric. The youngest deformation in the areas is a series of WNW trending, regional scale antiforms and synforms which exert a first order control on the topography of the region.

  2. Clinal variation at phenology-related genes in spruce: parallel evolution in FTL2 and Gigantea?

    PubMed

    Chen, Jun; Tsuda, Yoshiaki; Stocks, Michael; Källman, Thomas; Xu, Nannan; Kärkkäinen, Katri; Huotari, Tea; Semerikov, Vladimir L; Vendramin, Giovanni G; Lascoux, Martin

    2014-07-01

    Parallel clines in different species, or in different geographical regions of the same species, are an important source of information on the genetic basis of local adaptation. We recently detected latitudinal clines in SNPs frequencies and gene expression of candidate genes for growth cessation in Scandinavian populations of Norway spruce (Picea abies). Here we test whether the same clines are also present in Siberian spruce (P. obovata), a close relative of Norway spruce with a different Quaternary history. We sequenced nine candidate genes and 27 control loci and genotyped 14 SSR loci in six populations of P. obovata located along the Yenisei river from latitude 56°N to latitude 67°N. In contrast to Scandinavian Norway spruce that both departs from the standard neutral model (SNM) and shows a clear population structure, Siberian spruce populations along the Yenisei do not depart from the SNM and are genetically unstructured. Nonetheless, as in Norway spruce, growth cessation is significantly clinal. Polymorphisms in photoperiodic (FTL2) and circadian clock (Gigantea, GI, PRR3) genes also show significant clinal variation and/or evidence of local selection. In GI, one of the variants is the same as in Norway spruce. Finally, a strong cline in gene expression is observed for FTL2, but not for GI. These results, together with recent physiological studies, confirm the key role played by FTL2 and circadian clock genes in the control of growth cessation in spruce species and suggest the presence of parallel adaptation in these two species.

  3. Social Structure and Social Change in Eastern Europe.

    ERIC Educational Resources Information Center

    Fischer, George; Schenkel, Walter

    This specialized bibliography of scholarly writings since 1945 on Eastern Europe covers the countries of Albania, Bulgaria, Czechoslovakia, Greece, Hungary, Poland, Romania, and Yugoslavia. Distinct entries number about 700 and cover works published in English in the United States and Great Britain and also sources in French and German published…

  4. ASSOCIATIONS OF EASTERN REDCEDAR AND COMMUNITY STRUCTURE OF SMALL MAMMALS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianas), a native but invasive species in the Great Plains, has been associated with several changes in ecosystem function. It can lead to a reduction in herbaceous biomass in the canopy zone, alter species composition, and...

  5. Growth declines in red spruce

    SciTech Connect

    Zedaker, S.M.; Hyink, D.M.; Smith, D.W.

    1987-01-01

    Over the past two decades second-growth red spruce stands in the Northeast have demonstrated declines in radial increment. Some observers are implicating air pollution as a primary cause of the declines, based on recently acquired increment cores from dominant trees. Various forms of air pollution (O/sub 3/, NO/sub x/, SO/sub 2/, and trace metals) are known to reduce growth and development of tree species, but few studies have provided concrete evidence of regional pollution-caused declines in forest ecosystems. Recently published evidence of a synchronous, consistent, and unprecedented regional decline in red spruce should be weighed against the realization that radial increment in red spruce declines naturally as stands age. Separating anthropogenic stress-caused growth patterns from natural stand dynamics requires an in-depth knowledge of forest growth and yield, tree silvics, and forest ecosystem processes. Detailed analyses of growth by stand characteristics - site index, density, elevation, stand history - will be necessary to implicate air pollution as a primary cause of red spruce decline.

  6. The Crustal Structure and Seismicity of Eastern Venezuela

    NASA Astrophysics Data System (ADS)

    Schmitz, M.; Martins, A.; Sobiesiak, M.; Alvarado, L.; Vasquez, R.

    2001-12-01

    Eastern Venezuela is characterized by a moderate to high seismicity, evidenced recently by the 1997 Cariaco earthquake located on the El Pilar Fault, a right lateral strike slip fault which marks the plate boundary between the Caribbean and South-American plates in this region. Recently, the seismic activity seems to migrate towards the zone of subduction of the Lesser Antilles in the northeast, where a mb 6.0 earthquake occurred in October 2000 at 120 km of depth. Periodical changes in the seismic activity are related to the interaction of the stress fields of the strike-slip and the subduction regimes. The seismic activity decreases rapidly towards to the south with some disperse events on the northern edge of the Guayana Shield, related to the Guri fault system. The crustal models used in the region are derived from the information generated by the national seismological network since 1982 and by microseismicity studies in northeastern Venezuela, coinciding in a crustal thickness of about 35 km in depth. Results of seismic refraction measurements for the region were obtained during field campains in 1998 (ECOGUAY) for the Guayana Shield and the Cariaco sedimentary basin and in 2001 (ECCO) for the Oriental Basin. The total crustal thickness decreases from about 45 km on the northern edge of the Guayana Shield to some 36 km close to El Tigre in the center of the Oriental Basin. The average crustal velocity decreases in the same sense from 6.5 to 5.8 km/s. In the Cariaco sedimentary basin a young sedimentary cover of 1 km thickness with a seismic velocity of 2 km/s was derived. Towards the northern limit of the South-American plate, no deep seismic refraction data are available up to now. The improvement of the crustal models used in that region would constitute a step forward in the analysis of the seismic hazard. Seismic refraction studies funded by CONICIT S1-97002996 and S1-2000000685 projects and PDVSA (additional drilling and blasting), recording equipment

  7. Deep structure of Eastern part of Bandung Basin based on 2D resistivity structure

    NASA Astrophysics Data System (ADS)

    Harja, Asep

    2013-09-01

    Bandung basin is an intramontane basin located in West Java, extending from west to east along 35 km and north to south along 15 km distance, with elevation of 660-680 m. The plain in the eastern part is the basin center with lake deposit as primary sediment filling the basin. Investigation of the subsurface structure and thickness of the basin is the main topic in this research. Beside the deeper structure of the basin, the shallow structure is also very important to be revealed since human activities are concentrated in this part. The latter is supposed to explain phenomenon related to the flood and drought that frequently occur in the area. Controlled-source audio-frequency magneto telluric (CSAMT) is a highly effective electromagnetic (EM) method to deploy in this area. Its robustness toward electromagnetic noises related to human and industrial activities particularly in the eastern part of the basin is the strong point of this method. It uses a grounded horizontal electric dipole as artificial source of electromagnetic signal that ensures data with a high signal to noise (S/N) ratio. This method is capable to map subsurface resistivity structure with high sensitivity to resistivity contras and deeper penetration. 1D inversion scheme was used to the far-field component of CSAMT data (plane wave assumption) in order to obtain resistivity cross-sections that are more suitable with the basin's structure complexity. The results show that until the depth of more than 200 m, no high resistivity structure is found. This unlikely indicated the presence of volcanic rocks beneath the area. The subsurface resistivity distribution is dominated by tens of Om, indicating that the basement comprises deep marine sediment. In addition, clay lens are also indicated in the resulting resistivity structure. Based on 2D view of resistivity cross-sections based 1D inverted and 2D inversion, it is found that a low resistivity elongation extends in southeast-northwest direction at

  8. Effects of Artificial Defoliation of Pines on the Structure and Physiology of the Soil Fungal Community of a Mixed Pine-Spruce Forest

    PubMed Central

    Cullings, Ken; Raleigh, Christopher; New, Michael H.; Henson, Joan

    2005-01-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems. PMID:15812031

  9. Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest.

    PubMed

    Cullings, Ken; Raleigh, Christopher; New, Michael H; Henson, Joan

    2005-04-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

  10. Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest

    NASA Technical Reports Server (NTRS)

    Cullings, Ken; Raleigh, Christopher; New, Michael H.; Henson, Joan

    2005-01-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

  11. Improved white spruce (Picea glauca) genome assemblies and annotation of large gene families of conifer terpenoid and phenolic defense metabolism.

    PubMed

    Warren, René L; Keeling, Christopher I; Yuen, Macaire Man Saint; Raymond, Anthony; Taylor, Greg A; Vandervalk, Benjamin P; Mohamadi, Hamid; Paulino, Daniel; Chiu, Readman; Jackman, Shaun D; Robertson, Gordon; Yang, Chen; Boyle, Brian; Hoffmann, Margarete; Weigel, Detlef; Nelson, David R; Ritland, Carol; Isabel, Nathalie; Jaquish, Barry; Yanchuk, Alvin; Bousquet, Jean; Jones, Steven J M; MacKay, John; Birol, Inanc; Bohlmann, Joerg

    2015-07-01

    White spruce (Picea glauca), a gymnosperm tree, has been established as one of the models for conifer genomics. We describe the draft genome assemblies of two white spruce genotypes, PG29 and WS77111, innovative tools for the assembly of very large genomes, and the conifer genomics resources developed in this process. The two white spruce genotypes originate from distant geographic regions of western (PG29) and eastern (WS77111) North America, and represent elite trees in two Canadian tree-breeding programs. We present an update (V3 and V4) for a previously reported PG29 V2 draft genome assembly and introduce a second white spruce genome assembly for genotype WS77111. Assemblies of the PG29 and WS77111 genomes confirm the reconstructed white spruce genome size in the 20 Gbp range, and show broad synteny. Using the PG29 V3 assembly and additional white spruce genomics and transcriptomics resources, we performed MAKER-P annotation and meticulous expert annotation of very large gene families of conifer defense metabolism, the terpene synthases and cytochrome P450s. We also comprehensively annotated the white spruce mevalonate, methylerythritol phosphate and phenylpropanoid pathways. These analyses highlighted the large extent of gene and pseudogene duplications in a conifer genome, in particular for genes of secondary (i.e. specialized) metabolism, and the potential for gain and loss of function for defense and adaptation.

  12. Wave speed structure of the eastern North American margin

    NASA Astrophysics Data System (ADS)

    Savage, B.; Covellone, B. M.; Shen, Y.

    2017-02-01

    The eastern North American margin (ENAM) is the result of nearly a billion years of continental collision and rifting. To the west of this margin lies thick continental lithosphere of the North American craton, and to the east is oceanic lithosphere in the Atlantic. The substantial changes in lithosphere thickness at this boundary are thought to drive asthenosphere upwelling along the edge of the continent. Through iterative, full-waveform, ambient noise tomography, we observe a heterogeneous low wave speed margin along the continent in the upper mantle. Multiple low wave speed features imaged within the margin are consistent with asthenospeheric upwelling due to edge-driven convection. Also within the margin are high wave speed anomalies that maybe the remnants of eclogitic delamination of the Appalachian crustal root, which contribute to convection at the margin. Edge driven, small-scale convection keeps the margin weak and thus controls the large scale plate tectonic patterns and the crustal deformation. The imaged mantle wave speed anomalies, interpreted as edge-driven convection, correlate with and may increase the likelihood of damaging earthquakes in the eastern portion of North America.

  13. Red spruce physiology and growth in response to elevated CO[sub 2], water stress and nutrient limitations

    SciTech Connect

    Samuelson, L.J.

    1992-01-01

    Spruce-fir ecosystems of the eastern United States interest scientists because of reported changes in population growth. This research examined the growth and physical responses of red spruce seedlings (Picea rubens Sarg.) to change in atmospheric CO[sub 2], water and nutrient availability to determine the response of this species to potential climatic changes. Red spruce seedlings were grown from seed for 1 year in ambient (374 ppm) or elevated (713 ppm) CO[sub 2] in combination with low or high soil fertility treatment, and well-watered or water-stressed conditions. Red spruce seedlings grown with limited nutrient and water availability increased growth in elevated CO[sub 2] as did seedlings grown with high soil fertility treatment and ample water. At 12 months of age, elevated CO[sub 2]-grown seedlings had greater dry weight, height, diameter and specific leaf weight than ambient CO[sub 2[minus

  14. Space sequestration below ground in old-growth spruce-beech forests-signs for facilitation?

    PubMed

    Bolte, Andreas; Kampf, Friederike; Hilbrig, Lutz

    2013-01-01

    Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

  15. Space sequestration below ground in old-growth spruce-beech forests—signs for facilitation?

    PubMed Central

    Bolte, Andreas; Kampf, Friederike; Hilbrig, Lutz

    2013-01-01

    Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area. PMID:24009616

  16. Organic matter characteristics in boreal forest soils under stands of silver birch, Norway spruce, and Norway spruce with a mixture of silver birch

    NASA Astrophysics Data System (ADS)

    Smolander, A.; Kitunen, V.

    2012-04-01

    The aim was to study how tree species and a tree species mixture affect microbial C and N transformations and two major plant secondary compound groups, terpenes and phenolic compounds in soil. The study site was a tree-species experiment in middle-eastern part of Finland containing plots of 43-year-old silver birch, Norway spruce and Norway spruce with a mixture of silver birch (22 and 37 % birch of the total stem number). Soil was podzol and humus type mor. Samples were taken from the organic layer. C and N in the microbial biomass, rates of C mineralization (CO2 evolution), net N mineralization and nitrification, and concentrations of total water-soluble phenolic compounds, condensed tannins and different kind of terpenes were measured. Amounts of C and N in the microbial biomass and the rates of C mineralization and net N mineralization were all lower under spruce than birch, and particularly net N mineralization was stimulated by birch mixture. Concentrations of total water-soluble phenolic compounds were on a similar level, irrespective of tree species. However, there were less low-molecular-weight phenolics and more high-molecular-weight phenolics under spruce than birch. Concentrations of condensed tannins and both sesqui- and diterpenes were all higher under spruce than birch but the concentrations of triterpenes were similar in all soils. The difference between tree species was greatest with monoterpenes which were measured from both organic layer and soil atmosphere: high concentrations under spruce and negligible under birch. Birch mixture tended to decrease the concentrations of condensed tannins and mono-, sesqui- and diterpenes.

  17. Cenozoic contractional reactivation of Mesozoic extensional structures in the Eastern Cordillera of Colombia

    NASA Astrophysics Data System (ADS)

    Mora, AndréS.; Parra, Mauricio; Strecker, Manfred R.; Kammer, Andreas; Dimaté, Cristina; RodríGuez, Fernando

    2006-04-01

    The Eastern Cordillera of Colombia is key to understanding the role of inherited basement anisotropies in the evolution of active noncollisional mountain belts. In particular, the Rio Blanco-Guatiquía region of the Eastern Cordillera is exemplary in displaying a variety of phenomena that document the importance of the orientation, geometry, and segmentation of preorogenic anisotropies. We document the first unambiguous evidence that extensional basement structures played an important role in determining the locus of deformation during contractional reactivation in the Eastern Cordillera. Detailed structural field mapping and analysis of industry seismic reflection profiles have helped to identify the inherited San Juanito, Naranjal, and Servitá normal faults and associated transfer faults as important structures that were inverted during the Cenozoic Andean orogeny. Apparently, the more internal faults in the former rift basin were not properly oriented for an efficient reactivation in contraction. However, these faults have a fundamental role as strain risers, as folding is concentrated west of them. In contrast, reactivated normal faults such as the more external Servitá fault are responsible for uplifting the eastern flank of the Eastern Cordillera. In addition, these structures are adjacent and intimately linked to the development of thin-skinned faults farther east. In part, the superimposed compression in this prestrained extensional region is compensated by lateral escape. The dominant presence of basement involved buckling and thrusting, and the restricted development of thin-skinned thrusting in this inversion orogen makes the Eastern Cordillera a close analog to the intraplate Atlas Mountains of Morocco and other inverted sectors of the Andean orogen farther south.

  18. SPRUCE experiment data infrastructure development

    NASA Astrophysics Data System (ADS)

    Krassovski, Misha

    2013-04-01

    The SPRUCE experiment (http://mnspruce.ornl.gov) is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. It is an ecosystem considered especially vulnerable to climate change, and anticipated to be near its tipping point with respect to climate change. Responses to warming and interactions with increased atmospheric CO2 concentration are anticipated to have important feedbacks on the atmosphere and climate, because of the high carbon stocks harbored by such ecosystems. Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL) provides data management support for the SPRUCE experiment including data infrastructure design, development, long-term storage and dissemination. This presentation is going to show how the whole data infrastructure was designed, discuss major problems that are common for remote observational systems and unique for this particular implementation. It will demonstrate the dataflow starting from the sensors and ending at the archiving/distribution points, discuss types of hardware and software used, and examine considerations that were used to choose them.

  19. SPRUCE: Spruce and Peatland Responses under Climatic and Environmental Change

    DOE Data Explorer

    SPRUCE is an experiment to assess the response of northern peatland ecosystems to increases in temperature and exposures to elevated atmospheric CO2 concentrations. It is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. It is an ecosystem considered especially vulnerable to climate change, and anticipated to be near its tipping point with respect to climate change. Responses to warming and interactions with increased atmospheric CO2 concentration are anticipated to have important feedbacks on the atmosphere and climate, because of the high carbon stocks harbored by such ecosystems.[copied from http://mnspruce.ornl.gov/] While some data files are restricted to access by project members only, others are available for public download now, even as research is being actively conducted.

  20. Structural framework across the Bastar craton - the Eastern Ghats Granulite Belt interface: Implications for making of eastern Gondwana

    NASA Astrophysics Data System (ADS)

    Patole, Vishal; Nasipuri, Pritam

    2015-04-01

    The transformation of palaeo-continents involve breakup, dispersal and reassembly of cratonic blocks by collisional suturing that develop a network of orogenic (mobile) belts around the periphery of the stable cratons. During the collision, partial melting of the different crustal blocks produces migmatites at the craton-mobile belt interface. Thus, migmatites at the craton-mobile belt contact can provide valuable information regarding the pressure-temperature conditions of the melting of lower crust during supercontinent building processes. In this contribution, we document the structural framework across the Bastar craton- Eastern Ghats Granulite Belt (EGGB) interface that developed during the accretion of EGGB over Bastar craton. Near Bhawanipatna, Orissa, Eastern India, the granulites of the mobile belt are juxtaposed against the granitic rocks of the Bastar craton. Away from the contact domain, the cratonic granite is non-migmatitic and blasto-porphyritic in nature that gradually transforms to migmatitic variety towards the contact domain. In the non-migmatitic variety, the E-W trending stromatic leucozomes and biotite-hornblende rich fabric (S1) wraps around recrystallized K-feldspar augens. In the migmatitic variety towards the contact domain, NNE-SSW trending diatexite leucozomes (S2) are prominent and the intensity of melting and tightness of folding increases towards the contact domain. Structural measurements indicate that the S1 fabric is folded with the development of NNE-SSW axial plane with easterly plunging fold axis (50 -> 050N). To correlate the geological history of EGGB in the context of supercontinent reconstruction, the existence of a cratonic block consisting of India - Madagascar - Sri Lanka - Enderby Land-Kalahari ("IMSLEK") from 3000 Ma upto 750 Ma has been invoked by several authors. The apparent continuity of the Grenvillian metamorphic orogen along the East Antarctica-Australia-India margin has been taken as conclusive evidence for the

  1. Virulence structure of the eastern U.S. wheat powdery mildew population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the population structure of wheat powdery mildew in the eastern 2 U.S., and the most recent report on virulence in this pathogen population involved isolates 3 collected in 1993-94. In the present study, wheat leaves naturally infected with powdery mildew 4 were collected from ...

  2. The Social Consequences of Postcommunist Structural Change: An Analysis of Suicide Trends in Eastern Europe

    ERIC Educational Resources Information Center

    Minagawa, Yuka

    2013-01-01

    Guided by Durkheim's classic theory of suicide, this article examines suicide trends and determinants in Eastern European countries for the period of 1989-2006, with particular attention given to the association between postcommunist social change and suicide mortality. I find that countries characterized by more drastic structural change…

  3. The extent and meaning of hybridization and introgression between Siberian spruce (Picea obovata) and Norway spruce (Picea abies): cryptic refugia as stepping stones to the west?

    PubMed

    Tsuda, Yoshiaki; Chen, Jun; Stocks, Michael; Källman, Thomas; Sønstebø, Jørn Henrik; Parducci, Laura; Semerikov, Vladimir; Sperisen, Christoph; Politov, Dmitry; Ronkainen, Tiina; Väliranta, Minna; Vendramin, Giovanni Giuseppe; Tollefsrud, Mari Mette; Lascoux, Martin

    2016-06-01

    Boreal species were repeatedly exposed to ice ages and went through cycles of contraction and expansion while sister species alternated periods of contact and isolation. The resulting genetic structure is consequently complex, and demographic inferences are intrinsically challenging. The range of Norway spruce (Picea abies) and Siberian spruce (Picea obovata) covers most of northern Eurasia; yet their geographical limits and histories remain poorly understood. To delineate the hybrid zone between the two species and reconstruct their joint demographic history, we analysed variation at nuclear SSR and mitochondrial DNA in 102 and 88 populations, respectively. The dynamics of the hybrid zone was analysed with approximate Bayesian computation (ABC) followed by posterior predictive structure plot reconstruction and the presence of barriers across the range tested with estimated effective migration surfaces. To estimate the divergence time between the two species, nuclear sequences from two well-separated populations of each species were analysed with ABC. Two main barriers divide the range of the two species: one corresponds to the hybrid zone between them, and the other separates the southern and northern domains of Norway spruce. The hybrid zone is centred on the Urals, but the genetic impact of Siberian spruce extends further west. The joint distribution of mitochondrial and nuclear variation indicates an introgression of mitochondrial DNA from Norway spruce into Siberian spruce. Overall, our data reveal a demographic history where the two species interacted frequently and where migrants originating from the Urals and the West Siberian Plain recolonized northern Russia and Scandinavia using scattered refugial populations of Norway spruce as stepping stones towards the west.

  4. Stand and landscape level effects of a major outbreak of spruce beetles on forest vegetation in the Copper River Basin, Alaska

    USGS Publications Warehouse

    Allen, J.L.; Wesser, S.; Markon, C.J.; Winterberger, K.C.

    2006-01-01

    From 1989 to 2003, a widespread outbreak of spruce beetles (Dendroctonus rufipennis) in the Copper River Basin, Alaska, infested over 275,000 ha of forests in the region. During 1997 and 1998, we measured forest vegetation structure and composition on one hundred and thirty-six 20-m ?? 20-m plots to assess both the immediate stand and landscape level effects of the spruce beetle infestation. A photo-interpreted vegetation and infestation map was produced using color-infrared aerial photography at a scale of 1:40,000. We used linear regression to quantify the effects of the outbreak on forest structure and composition. White spruce (Picea glauca) canopy cover and basal area of medium-to-large trees [???15 cm diameter-at-breast height (1.3 m, dbh)] were reduced linearly as the number of trees attacked by spruce beetles increased. Black spruce (Picea mariana) and small diameter white spruce (<15 cm dbh) were infrequently attacked and killed by spruce beetles. This selective attack of mature white spruce reduced structural complexity of stands to earlier stages of succession and caused mixed tree species stands to lose their white spruce and become more homogeneous in overstory composition. Using the resulting regressions, we developed a transition matrix to describe changes in vegetation types under varying levels of spruce beetle infestations, and applied the model to the vegetation map. Prior to the outbreak, our study area was composed primarily of stands of mixed white and black spruce (29% of area) and pure white spruce (25%). However, the selective attack on white spruce caused many of these stands to transition to black spruce dominated stands (73% increase in area) or shrublands (26% increase in area). The post-infestation landscape was thereby composed of more even distributions of shrubland and white, black, and mixed spruce communities (17-22% of study area). Changes in the cover and composition of understory vegetation were less evident in this study

  5. Turbulence parameter inside and above a tall spruce site

    NASA Astrophysics Data System (ADS)

    Biermann, T.; Staudt, K.; Serafimovich, A.; Foken, T.

    2009-04-01

    In the EGER (ExchanGE processes in mountainous Regions) project, different physical, chemical and biological processes in the soil-vegetation-boundary-layer system were investigated. Field experiments were performed at the BayCEER research site Waldstein/Weidenbrunnen, a spruce site located in the Fichtelgebirge Mountains in North-Eastern Bavaria, which are challenging for their heterogeneity and orographically structured terrain. Turbulence structure, advection, flux gradients of meteorological and chemical quantities were observed within the first intensive observation period (IOP 1) in September and October 2007. Observations of turbulence structure were obtained by a vertical profile of sonic anemometers covering all parts of the forest up to the lower part of the roughness sub layer. Field observations are complemented by simulations of ACASA model (Advanced Canopy-Atmosphere-Soil Algorithm). Integral turbulence characteristics, the normalized standard deviation of a turbulent quantity, can be used to describe the structure of turbulence. A comparison between measured and predicted values shows whether turbulence is fully developed or not and is therefore used in quality assessment. For this quality control and as an input for models, when measurements are not available, parameterizations for profiles are needed. Since there is no uniform theory for those parameterizations inside a forest available, different approaches were tested with data collected during the EGER IOP1. In order to parameterize the integral turbulence characteristics of the wind components inside the roughness sub layer a dimensionless height ζ = hc L-1 should be used instead of ζ = z L-1, which is used above short vegetation. Profiles of integral turbulence characteristics from different ecosystems show that the decrease inside the roughness sub layer is similar but that parameterizations of profiles can not be generalized due to different stand structures. Selecting the profiles of the

  6. Clinal Variation at Phenology-Related Genes in Spruce: Parallel Evolution in FTL2 and Gigantea?

    PubMed Central

    Chen, Jun; Tsuda, Yoshiaki; Stocks, Michael; Källman, Thomas; Xu, Nannan; Kärkkäinen, Katri; Huotari, Tea; Semerikov, Vladimir L.; Vendramin, Giovanni G.; Lascoux, Martin

    2014-01-01

    Parallel clines in different species, or in different geographical regions of the same species, are an important source of information on the genetic basis of local adaptation. We recently detected latitudinal clines in SNPs frequencies and gene expression of candidate genes for growth cessation in Scandinavian populations of Norway spruce (Picea abies). Here we test whether the same clines are also present in Siberian spruce (P. obovata), a close relative of Norway spruce with a different Quaternary history. We sequenced nine candidate genes and 27 control loci and genotyped 14 SSR loci in six populations of P. obovata located along the Yenisei river from latitude 56°N to latitude 67°N. In contrast to Scandinavian Norway spruce that both departs from the standard neutral model (SNM) and shows a clear population structure, Siberian spruce populations along the Yenisei do not depart from the SNM and are genetically unstructured. Nonetheless, as in Norway spruce, growth cessation is significantly clinal. Polymorphisms in photoperiodic (FTL2) and circadian clock (Gigantea, GI, PRR3) genes also show significant clinal variation and/or evidence of local selection. In GI, one of the variants is the same as in Norway spruce. Finally, a strong cline in gene expression is observed for FTL2, but not for GI. These results, together with recent physiological studies, confirm the key role played by FTL2 and circadian clock genes in the control of growth cessation in spruce species and suggest the presence of parallel adaptation in these two species. PMID:24814465

  7. Image crustal structure of eastern Oklahoma City with TOMODD

    NASA Astrophysics Data System (ADS)

    Chen, C.; Holland, A. A.; Keller, R. G.

    2012-12-01

    There has been a dramatic increase in earthquake activity in Oklahoma since 2009. This dramatic increase was also matched by a marked increase in the number of operating seismic stations within the region. The additional stations include the Earthscope Transportable Arrays and temporary stations provided by the U. S. Geological Survey. The additional seismic stations and earthquakes provide the ability to do local travel time tomography of the crust within the region. For this study we are focusing on the area near the Jones earthquake swarm, that occurred just east of Oklahoma City, and the M5.6, November 2011 Prague earthquake. Major structures are already known in the area, but little is known about crustal structure below the top of the Precambrian basement. We used regionally available and temporary seismic stations along with more than 2000 earthquakes within the region to develop a 3D tomographic model of the crust using TOMODD. The major structures within the area are the Nemaha Ridge, Wilzetta Fault, and Seminole Uplift, and they and other structures as well are expressed within the tomographic model. We are working on determining the resolution and interpretation of the tomographic images.

  8. Integrating remote sensing and magnetic data for structural geology investigation in pegmatite areas in eastern Afghanistan

    NASA Astrophysics Data System (ADS)

    Salehi, Ratib; Saadi, Nureddin M.; Khalil, Ahmed; Watanabe, Koichiro

    2015-01-01

    This study used an integrated approach to investigate pegmatite areas in eastern Afghanistan. The analysis of surface data, including a digital elevation model (DEM), and Landsat Enhanced Thematic Mapper Plus (ETM+) images, was combined with airborne magnetic data to better understand three-dimensional geology in the area. The ETM+ and DEM data were used to map geological structures at the surface, which indicate that the area consists of two main fault systems that trend NNE and E-W. The two trends represent the remnants of reactivated structures that formed under the stress regimes generated during the tectonic evolution of eastern Afghanistan. Magnetic data indicate an NE-SW trending basin. A two-dimensional schematic model shows that the basin gradually deepens toward the SW with depths to the magnetic basement ranging between 2 and 11.5 km. The integration of the results gave new insight into the tectonic evolution and structure patterns near the pegmatites area.

  9. Hierarchical analysis of genetic structure in the habitat-specialist Eastern Sand Darter (Ammocrypta pellucida).

    PubMed

    Ginson, Robert; Walter, Ryan P; Mandrak, Nicholas E; Beneteau, Courtney L; Heath, Daniel D

    2015-02-01

    Quantifying spatial genetic structure can reveal the relative influences of contemporary and historic factors underlying localized and regional patterns of genetic diversity and gene flow - important considerations for the development of effective conservation efforts. Using 10 polymorphic microsatellite loci, we characterize genetic variation among populations across the range of the Eastern Sand Darter (Ammocrypta pellucida), a small riverine percid that is highly dependent on sandy substrate microhabitats. We tested for fine scale, regional, and historic patterns of genetic structure. As expected, significant differentiation was detected among rivers within drainages and among drainages. At finer scales, an unexpected lack of within-river genetic structure among fragmented sandy microhabitats suggests that stratified dispersal resulting from unstable sand bar habitat degradation (natural and anthropogenic) may preclude substantial genetic differentiation within rivers. Among-drainage genetic structure indicates that postglacial (14 kya) drainage connectivity continues to influence contemporary genetic structure among Eastern Sand Darter populations in southern Ontario. These results provide an unexpected contrast to other benthic riverine fish in the Great Lakes drainage and suggest that habitat-specific fishes, such as the Eastern Sand Darter, can evolve dispersal strategies that overcome fragmented and temporally unstable habitats.

  10. Mantle Structures between Guatemala and the Eastern USArray

    NASA Astrophysics Data System (ADS)

    Chu, R.; Helmberger, D. V.; Wei, S.

    2015-12-01

    While cratons are stable features based on their ages, they apparently can be disturbed by flattened slabs and hidden hotspots. When these slabs break up they provide a host of volatiles which interact with the old lithosphere producing complicated structures. These have been imaged by a host of techniques involving modeling regional waveforms and an assortment of tomography models. Here we test these models against a deep March 25th, 2013 Guatemala event at a depth of 190 km, which produced an excellent set of TA record sections that provide dense sampling of the structure, spanning the ranges from 15 to 35 degrees. Because the structure in the southern Gulf of Mexico is uncertain, we first concentrated on deriving a pure-path model for this region. Both P and SH triplication data is well sampled by stations located in Florida from 13 degrees and beyond. The best fitting model is modified from the SH model ATL (Grand and Helmberger, 1984) with a P-model in Zhao and Helmberger (1993). These models contain a high-velocity lid structure along with a low-velocity gradient at depth. This allows the up-going S wave (direct) to remain the first arrival traveling in the fast lid to beyond 180 degrees. The modeling of the direct S along with the diving phases and depth phase triplications, pP, sP, sS allows for a well constrained model. This model ATLm and the earlier craton model CR along with mixture of the two are tested with the Cut-and-Paste (CAP) code on whole 3 component records. Over large paths of data produced by the southern US support the so-called X-phase arrivals which are produced by a 300 km transition. This feature breas down at large distance (>25 degree) along a northwest-southeast boundary. Data at larger distances indicate a complexity in the 660 transition which appears to be caused by a fast slab located at the top of the lower mantle. Variation in the EF-CD branches of pP and sP display changes of up to 5 s and sS up to 10 s, associated with the

  11. Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

    USGS Publications Warehouse

    Poag, C.W.

    2005-01-01

    This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. ?? 2005 Geological Society of America.

  12. Reconstructing the landscape structure of the Lena-Angara interfluve (south part of Eastern Siberia)

    NASA Astrophysics Data System (ADS)

    Atutova, Zhanna

    2015-04-01

    Historical-geographical reconstructions of the landscape structure of territories developed in the remote past constitute the necessary element in the chain of research into the dynamics and the degree of transformation of geosystems caused by the influence of the natural regularities and anthropogenic factors. The objective of this study is to determine the specific features of the territory of the Lena-Angara interfluve in the late 19th - early 20th centuries in the interest of a subsequent different-time comparative analysis of the landscape situation. An analysis of the features inherent in the functioning of the geosystems of the Lena-Angara interfluve was made by using, as an example, an elevated plateau with the sources of the Kuda river as well as of the Ilga and Kuda rivers. The relief is represented by a tableland with narrow crests of the watersheds, heavily dissected by a dense network of the valleys of rivers. The denudation processes created planate table-shaped elevations and plateaus whose range of absolute altitudes varies between 400 and 1000 m. The analysis of the landscape structure showed that the study territory was the home for mountain-taiga dark-coniferous and deciduous classes of facies. Larch, spruce-larch and, in places, pine-larch subshrub-grass-moss forests grew within the basins of the Ilga and Kulenga rivers. The watershed spaces of the Ilga-Kuda interfluve, and also the slopes of the upper reaches of the Kuda river were occupied by Siberian stone pine and larch-spruce subshrub-moss groups of facies. In spite of the ubiquitous occurrence of taiga-forest ranges, most of them transformed to derivative groups of facies. Forest fires gave impetus to a widespread occurrence of coniferous/small-leaved complexes in burned-over areas. The study area was poorly populated at the period under investigation; therefore, cultivated lands occupied very small territories. The upper reaches of the Kulenga river included small tracts of arable land

  13. Structural interpretation of seismic reflection data from eastern Salt Range and Potwar Plateau, Pakistan

    SciTech Connect

    Pennock, E.S.; Lillie, R.J.; Zaman, A.S.H.; Yousaf, M.

    1989-07-01

    Approximately 1600 km of seismic reflection profiles from the eastern Salt Range and Potwar Plateau (SR/PP) of Pakistan is integrated with available magnetostratigraphic, surface geologic, and well data to classify structural styles, determine the timing of deformation, and estimate the amount of telescoping of the sedimentary cover. The eastern SR/PP are similar to other fold-and-thrust belts underlain by evaporites in that (1) it is part of a zone of overthrusting that extends considerably farther over the Himalayan foreland than adjacent areas not underlain by evaporites, (2) the overall thrust wedge has a narrow cross-sectional taper, (3) structures verge toward the hinterland as well as toward the foreland, and (4) fold trends are long and continuous, consisting of tight salt-cored anticlines separated by broad synclines. 11 figures, 1 table.

  14. Factors affecting spruce establishment and recruitment near western treeline, Alaska

    NASA Astrophysics Data System (ADS)

    Miller, A. E.; Sherriff, R.; Wilson, T. L.

    2015-12-01

    Regional warming and increases in tree growth are contributing to increased productivity near the western forest margin in Alaska. The effects of warming on seedling recruitment has received little attention, in spite of forecasted forest expansion near western treeline. Here, we used stand structure and environmental data from white spruce (Picea glauca) stands (n = 95) sampled across a longitudinal gradient to explore factors influencing white spruce growth, establishment and recruitment in southwest Alaska. Using tree-ring chronologies developed from a subset of the plots (n = 30), we estimated establishment dates and basal area increment (BAI) for trees of all age classes across a range of site conditions. We used GLMs (generalized linear models) to explore the relationship between tree growth and temperature in undisturbed, low elevation sites along the gradient, using BAI averaged over the years 1975-2000. In addition, we examined the relationship between growing degree days (GDD) and seedling establishment over the previous three decades. We used total counts of live seedlings, saplings and live and dead trees, representing four cohorts, to evaluate whether geospatial, climate, and measured plot covariates predicted abundance of the different size classes. We hypothesized that the relationship between abundance and longitude would vary by size class, and that this relationship would be mediated by growing season temperature. We found that mean BAI for trees in undisturbed, low elevation sites increased with July maximum temperature, and that the slope of the relationship with temperature changed with longitude (interaction significant with 90% confidence). White spruce establishment was positively associated with longer summers and/or greater heat accumulation, as inferred from GDD. Seedling, sapling and tree abundance were also positively correlated with temperature across the study area. The response to longitude was mixed, with smaller size classes

  15. White Spruce Regeneration Following a Major Spruce Beetle Outbreak in Forests on the Kenai Peninsula, Alaska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Between 1987 and 2000, a spruce beetle (Dendroctonus rufipennis) epidemic infested 1.19 million hectares of spruce (Picea spp.) forests in Alaska, killing most of the large diameter trees. We evaluated whether these forests would recover to their pre-outbreak density, and determined the site conditi...

  16. Fertilization Affects Branching Pattern in Norway Spruce

    NASA Astrophysics Data System (ADS)

    Palmroth, S.; Stenberg, P.; Smolander, H.

    2001-12-01

    The increase in stand productivity from fertilization can be attributed to an increase in photosynthetic capacity, and a faster accumulation of leaf area index (LAI). Differences in the steady-state LAI are likely to reflect differences in PAR interception and/or conversion efficiency at shoot and leaf level. Furthermore, shoots ability to export carbohydrates to developing buds could be the mechanism responsible for light dependent branching. Within-canopy distribution of PAR and leaf area form the core in process-based models that are used to assess impacts of changes in the environment on production and resource use efficiency of forest stands. However, feedback between structure and radiation environment is not often incorporated in the models. We studied the relationships between light availability, shoot structure and branching pattern in Norway spruce (Picea abies (L.) Karst.) at a long-term fertilization experiment at Flakaliden research area in northern Sweden. Sampling of shoots was designed to cover the variation in canopy exposure within the live crown zone, where current shoots were still found. Canopy openness was used as a measure of the light availability at the shoot?s position. Our data showed that, at similar canopy openness, shoots of fertilized trees were longer and the number and total length of daughters were higher than in control trees. Fertilization increased the steady-state LAI and resulted in a deeper canopy, i.e. foliage is produced and survive at much lower light levels.

  17. Growth strategy of Norway spruce under air elevated [CO2

    NASA Astrophysics Data System (ADS)

    Pokorny, R.; Urban, O.; Holisova, P.; Sprtova, M.; Sigut, L.; Slipkova, R.

    2012-04-01

    Plants will respond to globally increasing atmospheric CO2 concentration ([CO2]) by acclimation or adaptation at physiological and morphological levels. Considering the temporal onset, physiological responses may be categorized as short-term and morphological ones as long-term responses. The degree of plant growth responses, including cell division and cell expansion, is highly variable. It depends mainly on the specie's genetic predisposition, environment, mineral nutrition status, duration of CO2 enrichment, and/or synergetic effects of other stresses. Elevated [CO2] causes changes in tissue anatomy, quantity, size, shape and spatial orientation and can result in altered sink strength. Since, there are many experimental facilities for the investigation of elevated [CO2] effects on trees: i) closed systems or open top chambers (OTCs), ii) semi-open systems (for example glass domes with adjustable lamella windows - DAWs), and iii) free-air [CO2] enrichments (FACE); the results are still unsatisfactory due to: i) relatively short-term duration of experiments, ii) cultivation of young plants with different growth strategy comparing to old ones, iii) plant cultivation under artificial soil and weather conditions, and iv) in non-representative stand structure. In this contribution we are discussing the physiological and morphological responses of Norway spruce trees cultivated in DAWs during eight consecutive growing seasons in the context with other results from Norway spruce cultivation under air-elevated [CO2] conditions. On the level of physiological responses, we discuss the changes in the rate of CO2 assimilation, assimilation capacity, photorespiration, dark respiration, stomatal conductance, water potential and transpiration, and the sensitivity of these physiological processes to temperature. On the level of morphological responses, we discuss the changes in bud and growth phenology, needle and shoot morphology, architecture of crown and root system, wood

  18. Black spruce growth forms as a record of a changing winter environment at treeline, Quebec, Canada

    SciTech Connect

    Lavoie, C.; Payette, S. )

    1992-02-01

    The environmental conditions prevailing at treeline in subarctic Quebec have been reconstructed over the past 400 yr through a comparative analysis of tree rings and growth forms of black spruce (Picea mariana (Mill.) B.S.P.). Because black spruce growth forms are closely associated with the winter environment, they are a direct response to conditions of low temperature and windblown snow abrasion affecting living tissues at the snow-air interface. The age structure of supranival shoot populations was closely associated with periods of higher stem survival in winter most likely under snowier and windless conditions. Spruce growth on slopes and in the valley revealed periods of low tree-ring growth between 1601 and 1663 and between 1700 and 1904, respectively. A long-lasting period of low radial growth 1697 and 1939 prevailed in the hilltop site. During the 20th century, spruce height increased from 0.8 to 1.6 m on slopes and in the valley, while the basal level of abrasion from windblown snow increased from 0.1 to 0.5 m, suggesting an increasing trend towards warmer and snowier conditions. Abraded spruces growing during the Little Ice Age (1570-1880) were replaced by symmetrical trees during the 20th century. Supranival skirted and whorled spruces which dominated on the hilltop site during the 16th century reverted to infranival cushion and mat growth forms during the Little Ice Age. These stunted spruces were unable to recover during the recent warming because of their inability to catch enough drifting snow to allow vertical growth.

  19. Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

    NASA Astrophysics Data System (ADS)

    Sun, Weijia; Kennett, B. L. N.

    2016-04-01

    The Pn and Sn residuals from regional events provide strong constraints on the structure and lithological characteristics of the uppermost mantle beneath eastern China and its surroundings. With the dense Chinese Digital Seismic Network in eastern China, separate Pn and Sn tomographic inversions have been exploited to obtain P and S velocities at a resolution of 2° × 2° or better. The patterns of P velocities are quite consistent with the S velocities at depth of 50 and 60 km, but the amplitude of P wave speed anomalies are a little larger than those of S wave speed. The low P wave speed, high S wave speed, and low Vp/Vs ratio beneath the northern part of Ordos Basin are related to upwelling hot material. Abrupt changes in material properties are indicated from the rapid variations in the Vp/Vs ratio.

  20. Crustal structure beneath western and eastern Iceland from surface waves and receiver functions

    USGS Publications Warehouse

    Du, Z.; Foulger, G.R.; Julian, B.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.

    2002-01-01

    We determine the crustal structures beneath 14 broad-band seismic stations, deployed in western, eastern, central and southern Iceland, using surface wave dispersion curves and receiver functions. We implement a method to invert receiver functions using constraints obtained from genetic algorithm inversion of surface waves. Our final models satisfy both data sets. The thickness of the upper crust, as defined by the velocity horizon Vs = 3.7 km s-1, is fairly uniform at ???6.5-9 km beneath the Tertiary intraplate areas of western and eastern Iceland, and unusually thick at 11 km beneath station HOT22 in the far south of Iceland. The depth to the base of the lower crust, as defined by the velocity horizon Vs = 4.1 km s-1 is ???20-26 km in western Iceland and ???27-33 km in eastern Iceland. These results agree with those of explosion profiles that detect a thinner crust beneath western Iceland than beneath eastern Iceland. An earlier report of a substantial low-velocity zone beneath the Middle Volcanic Zone in the lower crust is confirmed by a similar observation beneath an additional station there. As was found in previous receiver function studies, the most reliable feature of the results is the clear division into an upper sequence that is a few kilometres thick where velocity gradients are high, and a lower, thicker sequence where velocity gradients are low. The transition to typical mantle velocities is variable, and may range from being very gradational to being relatively sharp and clear. A clear Moho, by any definition, is rarely seen, and there is thus uncertainty in estimates of the thickness of the crust in many areas. Although a great deal of seismic data are now available constraining the structures of the crust and upper mantle beneath Iceland, their geological nature is not well understood.

  1. Structural and tectonic evolution of the eastern Cayman Trough (Caribbean Sea) from seismic reflection data

    SciTech Connect

    Leroy, S.; Mauffret, A.; Pubellier, M.

    1996-02-01

    The eastern Cayman Trough preserves a record of the Late Cretaceous to Paleogene Caribbean history that is largely affected by Neogene strike-slip tectonics of the current plate boundary. We conducted an analysis of seismic data within the eastern Cayman Trough, based upon single and multi-channel seismic reflection profiles collected during the Seacarib II cruise in 1987 and the Casis cruise in 1992. These data show that the basement of the eastern Cayman Trough can be divided into four domains from east to west, with distinct morphologic and sedimentary character and inferred older to younger ages: (1) a province of rifted Mesozoic continental crust exhibiting seven parallel horst blocks striking northeast-southwest; (2) a continent-ocean transition between provinces 1 and 3 that exhibits seamounts, small hills, and sedimentary basins; (3) an Eocene oceanic crust with rough basement but smoother relief than the rifted crust; basement trends are roughly north-south and oblique to the northwest trend in domain 1, and (4) the northern Jamaica slope, which forms an east-west-trending slope, with northward-dipping strata that flank the three deeper water domains of the Cayman Trough. The domains are interpreted to be the product of the Eocene east-west opening of the Cayman Trough as a pull-apart basin in a left-lateral strike-slip setting. Closure of the 1100 km of Eocene and younger oceanic crust of the Cayman Trough places the fault-block province adjacent to the Belize margin of Central America. A Neogene phase of transpression has reactivated structures in the four domains, along with on-land structures described by previous authors in Jamaica. The proximity of the eastern margin of the Cayman Trough to petroliferous, continental rocks in Central America suggests an improved possibility of hydrocarbon potential. Unfortunately, sediment thicknesses of less than 1 km probably are not conducive to hydrocarbon formation.

  2. 9. LOOKING NORTH ON SPRUCE STREET, SHOWING MILLWRIGHT SHOP, FITTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NORTH ON SPRUCE STREET, SHOWING MILLWRIGHT SHOP, FITTING SHOP, ADMINISTRATION BUILDING AND ERECTING SHOP - UNION WORKS IN BACKGROUND. - Rogers Locomotive & Machine Works, Spruce & Market Streets, Paterson, Passaic County, NJ

  3. Software and Systems Producibility Collaboration and Experimentation Environment (SPRUCE)

    DTIC Science & Technology

    2014-04-01

    SOFTWARE AND SYSTEMS PRODUCIBILITY COLLABORATION AND EXPERIMENTATION ENVIRONMENT ( SPRUCE ) LOCKHEED MARTIN ADVANCED TECHNOLOGY LABORATORIES APRIL...PRODUCIBILITY COLLABORATION AND EXPERIMENTATION ENVIRONMENT ( SPRUCE ) 5a. CONTRACT NUMBER FA8750-08-C-0064 5b. GRANT NUMBER N/A 5c. PROGRAM...Environment ( SPRUCE ) project program execution during Phases 2, 3, and 4 spanning the period from April 2008 to September 2013. The SPRUCE was intended to

  4. Tectonic inversion in the Wandel Sea Basin: A new structural model of Kilen (eastern North Greenland)

    NASA Astrophysics Data System (ADS)

    Svennevig, Kristian; Guarnieri, Pierpaolo; Stemmerik, Lars

    2016-12-01

    The seminunatak Kilen in eastern North Greenland, with its complexly deformed Carboniferous-Cretaceous strata, is a key area to understand the tectonic history of the transform plate boundary between eastern North Greenland and Svalbard. Detailed 3-D geological mapping from oblique photogrammetry along with limited ground fieldwork and interpretation of previously published data forms the basis for a new structural model of Kilen. Previous structural models interpreted rhombic-shaped fault patterns as the evidence for strike-slip tectonics. These structures are here interpreted to be the result of a post-Coniacian NE-SW extension with NW-SE trending normal faults followed by later, N-S compression of presumable Paleocene-Eocene age, folding the faults passively and suggesting the presence of a basal detachment. Furthermore, two thrust sheets have been distinguished on Kilen: a lower Kilen Thrust Sheet and an upper Hondal Elv Thrust Sheet separated by a subhorizontal fault: the Central Detachment. The style of deformation and the structures described are interpreted as the result of Paleocene-Eocene N-S directed compression resulting in basin inversion with strike-slip faults only having minor status. This indicates that the Greenland margin as exposed on Kilen and the conjugate Svalbard margin in the West Spitsbergen fold-and-thrust belt are more similar than previously anticipated.

  5. Phylogeography of spruce beetles (Dendroctonus rufipennis Kirby) (Curculionidae: Scolytinae) in North America.

    PubMed

    Maroja, Luana S; Bogdanowicz, Steven M; Wallin, Kimberly F; Raffa, Kenneth F; Harrison, Richard G

    2007-06-01

    Tree-feeding insects that are widespread in north temperate regions are excellent models for studying how past glaciations have impacted differentiation and speciation. We used mitochondrial DNA (mtDNA) sequences and allele frequencies at nine microsatellite loci to examine genetic population structure across the current range of the spruce beetle (Dendroctonus rufipennis), an economically important insect in North America. Two major haplotype groups occur across northern North America, from Newfoundland to Alaska, on white spruce (Picea glauca), and a third distinctive haplotype group occurs throughout the Rocky Mountains on Engelmann spruce (Picea engelmannii). The two mtDNA lineages found in northern populations are 3-4% divergent from each other and from the lineages found in the Rocky Mountains. Analyses of microsatellite data also suggest the existence of major population groupings associated with different geographical regions. In the Pacific Northwest, concordant contact zones for genetically distinct populations of spruce beetles and their principal hosts appear to reflect recent secondary contact. Although we could detect no evidence of historical mtDNA gene flow between allopatric population groups, patterns of variation in the Pacific Northwest suggest recent hybridization and introgression. Together with the pollen record for spruce, they also suggest that beetles have spread from at least three glacial refugia. A minimum estimate of divergence time between the Rocky Mountain and northern populations was 1.7 Myr (million years), presumably reflecting the combined effects of isolation during multiple glacial cycles.

  6. Microbial communities in the litter of middle taiga bilberry-spruce forests

    NASA Astrophysics Data System (ADS)

    Sizonenko, T. A.; Zagirova, S. V.; Khabibullina, F. M.

    2010-10-01

    The structure of the microbial communities in the litters of middle-taiga bilberry-spruce forests was studied. It was found that ammonifying and oligonitrophilic microorganisms predominate in these communities. Two maximums in the population density of the microorganisms were observed in June and August. The number of microorganisms increased in the direction from the spruce trunks to the periphery of the crowns. The species composition of the micromycetes in the litters under the spruce crowns and within the intercrown spaces differed. The maximum population density of the fungi was found in the litter under the periphery of the spruce crowns, whereas the maximum diversity of the micromycetes was observed within the intercrown spaces. The Trichoderma, Trichosporiella, Penicillium, Paecilomyces, and Chaetomium genera were most abundant in the litters of the bilberry spruce forests. The Penicillium genus had the maximum abundance during the entire growing period, and the amount of Mycelia sterilia increased in the fall. The maximum diversity of the fungi was observed in May and June.

  7. Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola).

    PubMed

    Bodare, Sofia; Stocks, Michael; Yang, Jeng-Chuann; Lascoux, Martin

    2013-09-01

    Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long-term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3-0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false-positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4-8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin.

  8. Structurally controlled 'teleconnection' of large-scale mass wasting (Eastern Alps)

    NASA Astrophysics Data System (ADS)

    Ostermann, Marc; Sanders, Diethard

    2015-04-01

    In the Brenner Pass area (Eastern Alps) , closely ahead of the most northward outlier ('nose') of the Southern-Alpine continental indenter, abundant deep-seated gravitational slope deformations and a cluster of five post-glacial rockslides are present. The indenter of roughly triangular shape formed during Neogene collision of the Southern-Alpine basement with the Eastern-Alpine nappe stack. Compression by the indenter activated a N-S striking, roughly W-E extensional fault northward of the nose of the indenter (Brenner-normal fault; BNF), and lengthened the Eastern-Alpine edifice along a set of major strike-slip faults. These fault zones display high seismicity, and are the preferred locus of catastrophic rapid slope failures (rockslides, rock avalanches) and deep-seated gravitational slope deformations. The seismotectonic stress field, earthquake activity, and structural data all indicate that the South-Alpine indenter still - or again - exerts compression; in consequence, the northward adjacent Eastern Alps are subject mainly to extension and strike-slip. For the rockslides in the Brenner Pass area, and for the deep-seated gravitational slope deformations, the fault zones combined with high seismic activity predispose massive slope failures. Structural data and earthquakes mainly record ~W-E extension within an Eastern Alpine basement block (Oetztal-Stubai basement complex) in the hangingwall of the BNF. In the Northern Calcareous Alps NW of the Oetztal-Stubai basement complex, dextral faults provide defacement scars for large rockfalls and rockslides. Towards the West, these dextral faults merge into a NNW-SSE striking sinistral fault zone that, in turn, displays high seismic activity and is the locus of another rockslide cluster (Fern Pass cluster; Prager et al., 2008). By its kinematics dictated by the South-Alpine indenter, the relatively rigid Oetztal-Stubai basement block relays faulting and associated mass-wasting over a N-S distance of more than 60

  9. 2-D modelling of the anticlinal structures and structural development of the eastern fold belt of the Bengal Basin, Bangladesh

    NASA Astrophysics Data System (ADS)

    Sikder, Arif Mohiuddin; Alam, M. Mustafa

    2003-02-01

    Structural architecture of the Bengal Basin has been strongly controlled by the collision pattern of the Indian plate with the Burma and Tibetan plates. The eastern fold belt (EFB) of the basin, comprising a series of north-south-trending curvilinear anticlines and synclines, represents a fold-and-thrust belt that constitutes the westward continuation of Arakan-Chin fold system of the Indo-Burman Ranges. The present study is mainly concerned with the 2-D modelling of the anticlinal structures in order to develop an understanding about the process-response relationships between the structural style and tectonic evolution of the eastern fold belt. The dominant fold-generating mechanism is believed to be the east-west-directed compressional force arising from oblique subduction of the Indian plate beneath the Burma plate that resulted in the growth of fault-propagation folds above a detachment or decollement at depth, giving rise to the Neogene accretionary prism complex development. A prominent feature of the region is the major east-dipping thrusts separating successive accretionary wedges. In seismic sections, evidence for several phases of compressional deformation suggests that multiphase stress conditions were responsible for the structural expression of the fold belt. Deep seismic sections reveal that the base of folding is characterized by a low-interval velocity horizon that represents a detachment separating the upper folded zone from the lower, seismically coherent, nearly unfolded zone. This detachment coincides with the undercompacted pressured shale unit, which is thought to have played an important role in the structural development of the eastern fold belt. Clay mineralogical analysis reveals the presence of a low-density shale horizon within the dense and thick shale sequence that is thought to be an undercompacted pressured shale during the geological past, and was responsible for the initiation of decollement and incipient diapirism involving thin

  10. Early Mesozoic structural evolution of the eastern West Qinling, northwest China

    NASA Astrophysics Data System (ADS)

    Wu, Guo-Li; Meng, Qing-Ren; Duan, Liang; Li, Lin

    2014-09-01

    This paper aims to reconstruct Early Mesozoic structural development of the eastern West Qinling by integrating structural and geochronologic analyses. The results show that the eastern West Qinling experienced two-phase deformations, separated by a period of tectonic quiescence. Large-scale south-directed displacement of thrust sheets in association with folding characterized the first-phase deformation in Late Triassic time, leading to the formation of the West Qinling fold-and-thrust belt that is composed primarily of Paleozoic-Triassic strata. This fold-and-thrust belt is in general south-convexing arc-shaped, with an accumulated south-directed displacement being over 100 km. The folding and thrusting ended up during the Norian of the Late Triassic Epoch and were immediately followed by widespread granite intrusions. Marked uplift and erosion occurred in the Early Jurassic, resulting in exhumation of the Late Triassic granites. Transpressional deformation took place in the eastern West Qinling in the Middle Jurassic on account of occurrences of strike-slip faulting and refolding. In the easternmost part of the West Qinling exists a Permian-Triassic turbidite wedge that is bordered by a right-slip fault on the northeast and by a left-slip fault on the south, indicating a westward movement that was accommodated by slip faulting. It is argued that collision of the North and South China blocks was responsible for formation of the West Qinling fold-and-thrust belt in the Late Triassic, whereas Middle Jurassic transgression is considered as the result of westward extrusion of Permian-Triassic turbiditic materials from the East Qinling owing to renewed intracontinental convergence between the North and South China blocks. A tectonic model is advanced for Early Mesozoic tectonic development of the West Qinling.

  11. Structural lineaments in the basement rocks of the central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Kamel, A. F.

    The Egyptian basement rocks outcrop in Eastern Desert, southern Sinai and southwestern Desert. The rocks belong to Precambrian and consist of igneous and metamorphic rocks which are characterized by crystalline character. Not much work has been done on the tectonics and structure of the basement rocks in Eastern Desert. The present work is a photogeological interpretation of the structural lineaments representing dykes, faults and joints in central Eastern Desert to differentiate between igneous and metamorphic rocks. The photogeological interpretation was carried out using normal aerial photographs scale 1:40 000 and photomosaics scale 50 000. The main trends of lineaments in the studied area are: E-W, ENE-WSW and WNW-ESE, constituting 58.4% of the total length and 54.5% of the total number. Correlating the structural lineaments in igneous rocks of Gebel El Bakriya locality with those in the metamorphic rocks of Gebel Abu Mireiwa shows that there is a marked difference between the two types. Lineaments in igneous rocks are elongated and widely spaced while those in metamorphic rocks are short and closely spaced. The different trends of joints in igneous rocks can be arranged as follows: WNW>E-W>NW>NNW>ENE>NE>N-S>NNE while the different trends of lineaments in metamorphic rocks can be arranged as follows: E-W>ENE>WNW>NW>NNW>NE>N-S>NNE. Comparison between the structural contour maps constructed for the total length of all lineaments and those representing joints in igneous and metamorphic rocks indicates that igneous rocks have lower density of lineaments than metamorphic rocks. The total length of all lineaments in Gebel El Bakriya amounts to 375 km, while lineaments representing joints have a total length of 150 km. In the metamorphic rocks of Gebel Abu Mireiwa, the total length of all lineaments is 425 km and those representing joints have a total length of 175 km. It was found that there is a relationship between the structural lineaments and radioactivity of

  12. Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

    NASA Astrophysics Data System (ADS)

    Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

    2017-01-01

    Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

  13. Seismotectonic characteristics of the northernmost Longitudinal Valley, eastern Taiwan: Structural development of a vanishing suture

    NASA Astrophysics Data System (ADS)

    Shyu, J. Bruce H.; Chen, Chun-Fu; Wu, Yih-Min

    2016-12-01

    The Longitudinal Valley in eastern Taiwan is generally considered as the suture of the collision between the Philippine Sea and the Eurasian plates, and has attracted numerous geologic and seismologic studies. In the northernmost part of the valley, however, constraints on how structures develop as the suture turns into the Ryukyu subduction system offshore are still very limited. Therefore, we analyzed relocated seismicity distributions and focal mechanisms of earthquake sequences, together with tectonic geomorphic investigations to further understand the seismotectonic characteristics of this area. In our seismologic observations, we found two previously unidentified reverse faults in the northernmost part of the Longitudinal Valley suture. One is an E-W striking, south-dipping reverse fault near the Liwu River fan delta, and the other is a N-S striking, east-dipping reverse fault near the eastern Central Range front. Both these structures connect with a detachment at 10 km deep, and may connect with each other to form a curved structural system. The Meilun fault, a well-known active structure that ruptured in a M7.3 earthquake in October 1951, is not seismically active in the past two decades, and may just be part of a secondary branch of the major structural system. In the northernmost part of the Longitudinal Valley suture, we propose that as the Coastal Range bedrocks subduct northward beneath the Eurasian plate with the Philippine Sea plate, the shallow sediments of the Longitudinal Valley, being a buoyant block, do not subduct, but overthrust northward and westward instead.

  14. Crustal structure beneath the eastern Nepal Himalayas and southern Tibet from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Neupane, Arjun Sharma

    The Himalayas are the results of continental collision between the Indian plate and the Eurasian plate and serve as a natural site to study the physical causes and process of mountain building. The crustal structure beneath the Himalayas has been subject to numerous geophysical studies and the variation in the velocity structure across the Himalayan region suggests significant differences in the crustal structure between the southern and northern portion in that region. In this research, a P receiver function analysis has been conducted on data collected for 14 years (2000-2014) from 211 different stations in Eastern Nepal and Southern Tibet, to better understand the seismic velocity structure in the region. The stations cover a large area encompassing the south eastern plains of Nepal, Lesser and Greater Himalayas and the Southern Tibetan Plateau and provide an excellent geometry for seismic structure research. Following the rotation of the two horizontal components to the radial and transverse components and the time iterative deconvolution to obtain the receiver functions the H-K stacking method of Zhu and Kanamori(Zhu and Kanamori, 2000) has been used to convert the time domain receiver functions into H-K domain and obtain the values of crustal thickness and the ratio of the P and S wave velocities. The main trend in the receiver function analysis across the Himalaya from our study reflects the deepening of the moho from about 40 km beneath southern Nepal in the foothills of the Himalaya to about 80 km in southern Tibet. A locally steeper moho deep is obtained in the high range of Himalayas.

  15. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    PubMed

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position.

  16. Mantle transition zone thinning beneath eastern Africa: Evidence for a whole-mantle superplume structure

    NASA Astrophysics Data System (ADS)

    Mulibo, Gabriel D.; Nyblade, Andrew A.

    2013-07-01

    to S conversions from the 410 and 660 km discontinuities observed in receiver function stacks reveal a mantle transition zone that is ~30-40 km thinner than the global average in a region ~200-400 km wide extending in a SW-NE direction from central Zambia, across Tanzania and into Kenya. The thinning of the transition zone indicates a ~190-300 K thermal anomaly in the same location where seismic tomography models suggest that the lower mantle African superplume structure connects to thermally perturbed upper mantle beneath eastern Africa. This finding provides compelling evidence for the existence of a continuous thermal structure extending from the core-mantle boundary to the surface associated with the African superplume.

  17. A Contribution to the Understanding of the Regional Seismic Structure in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Di Luccio, F.; Thio, H.; Pino, N.

    2001-12-01

    Regional earthquakes recorded by two digital broadband stations (BGIO and KEG) located in the Eastern Mediterranean have been analyzed in order to study the seismic structure in this region. The area consists of different tectonic provinces, which complicate the modeling of the seismic wave propagation. We have modeled the Pnl arrivals using the FK-integration technique (Saikia, 1994) along different paths at the two stations, at several distances, ranging from 400 to 1500 km. Comparing the synthetics obtained by using several models compiled by other authors, we have constructed a velocity model, considering the informations deriving from group velocity distribution, in order to determine the finer structure in the analyzed paths. The model has been perturbed by trial and error until a compressional velocity profile has been found producing the shape of the observed waveforms. The crustal thickness, upper mantle P-wave velocity and 410-km discontinuity determine the shape of the observed waveform portions.

  18. The structure of the Ishtar Terra central and eastern parts and some tectonic problems of Venus

    NASA Technical Reports Server (NTRS)

    Bazilevskiy, A. T.

    1986-01-01

    Moving from the Maxwell Montes to the eastern edge of Ishtar Terra there is a gradual shift in submeridional meandering folded ranges in the western section of the area to straight intersecting disjunctive systems of connected faults and sublatitudinal shifts. These disjunctive systems evidently transform older structures; the major axis of the stresses created by them is primarily oriented sublatitudinally. Relative to younger structures, in the western they occupy a higher hypsometric position. The reason for the formation of this entire system may be a large astenospheric flow wihch rise in the region of Lakashmi Planum and Maxwell Montes and which spreads and plunges in an easterly direction, taking with it deformed blocks of the lithosphere.

  19. Canopy gap dynamics of second-growth red spruce-northern hardwood stands in West Virginia

    USGS Publications Warehouse

    Rentch, J.S.; Schuler, T.M.; Nowacki, G.J.; Beane, N.R.; Ford, W.M.

    2010-01-01

    Forest restoration requires an understanding of the natural disturbance regime of the target community and estimates of the historic range of variability of ecosystem components (composition, structure, and disturbance processes). Management prescriptions that support specific restoration activities should be consistent with these parameters. In this study, we describe gap-phase dynamics of even-aged, second-growth red spruce-northern hardwood stands in West Virginia that have been significantly degraded following early Twentieth Century harvesting and wildfire. In the current stage of stand development, gaps tended to be small, with mean canopy gap and extended canopy gap sizes of 53.4m2 and 199.3m2, respectively, and a canopy turnover rate of 1.4%year-1. The majority of gaps resulted from the death of one or two trees. American beech snags were the most frequent gap maker, partially due to the elevated presence of beech-bark disease in the study area. Gaps ranged in age from 1 to 28 years, had a mean of 13 years, and were unimodal in distribution. We projected red spruce to be the eventual gap filler in approximately 40% of the gaps. However, we estimated that most average-sized gaps will close within 15-20 years before red spruce canopy ascension is projected (30-60 years). Accordingly, many understory red spruce will require more than one overhead release - an observation verified by the tree-ring record and consistent with red spruce life history characteristics. Based on our observations, silvicultural prescriptions that include overhead release treatments such as thinning from above or small gap creation through selection harvesting could be an appropriate activity to foster red spruce restoration in the central Appalachians. ?? 2010 Elsevier B.V.

  20. Negative feedbacks on bark beetle outbreaks: widespread and severe spruce beetle infestation restricts subsequent infestation.

    PubMed

    Hart, Sarah J; Veblen, Thomas T; Mietkiewicz, Nathan; Kulakowski, Dominik

    2015-01-01

    Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced a severe landscape-scale spruce beetle infestation in the 1940s. We hypothesized that drought and warm temperatures would promote infestation, whereas small diameter and non-host trees, which may reflect past disturbance by spruce beetles, would inhibit infestation. Across the Southern Rocky Mountains, we found that climate and forest structure interacted to drive the 2000s infestation. Within the Flat Tops study area we found that stands infested in the 1940s were composed of higher proportions of small diameter and non-host trees ca. 60 years later. In this area, the 2000s infestation was constrained by a paucity of large diameter host trees (> 23 cm at diameter breast height), not climate. This suggests that there has not been sufficient time for trees to grow large enough to become susceptible to infestation. Concordantly, we found no overlap between areas affected by the 1940s infestation and the current infestation. These results show a severe spruce beetle infestation, which results in the depletion of susceptible hosts, can create a landscape template reducing the potential for future infestations.

  1. Influence of Mesozoic age structure on Miocene tectonic development in NE Anzoategui, Eastern Venezuela Basin

    SciTech Connect

    Sadler, P.; White, S.

    1996-08-01

    Structure within and surrounding the Quiamare-La Ceiba region, Eastern Venezuela Basin, is dominated by two major thrust fault systems. They were generated during Early-Middle Miocene time in response to oblique convergence of the Caribbean and South American plates. They are. respectively, the SE vergent NE-SW oriented Anaco fault system, and the SSE vergent ENE-WSW oriented Pirital fault system. The major structural feature associated with each fault system is a basement cored ramp anticline. New seismic data provides evidence that contributes to a better understanding of the sequence of tectonic development within and surrounding the Quiamare-La Ceiba region. Compressional structures in both the hanging wall and the footwall of the Pirital fault system appear to be inverted normal faults, that were previously active during Mesozoic time along the northern South America passive margin. A conjugate set of strike-slip faults is also present. They are oriented NNW-SSE, parallel to the Urica lineation, and SSW-NNE, respectively. A Mesozoic origin for these faults is suggested. Post-compressional relaxation during Plio-Pleistocene time resulted in the development of shallow, small scale normal faults. These normal faults appear to be localized by structural adjustments along the strike-slip fault sets. Existing oil and gas production within the Quiamare-La Ceiba region is from localized structural closures. Strike-slip faults dissect the prevailing structural grain, and may provide an additional hydrocarbon trapping mechanism.

  2. Structural and thermochronological evidence for Paleogene basement-involved shortening in the axial Eastern Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Saylor, Joel E.; Horton, Brian K.; Stockli, Daniel F.; Mora, Andrés; Corredor, Jaime

    2012-11-01

    Although most recent studies regard the northern Andes primarily as a low-shortening inversion orogen, new mapping and thermochronology along the paired basement-involved Floresta massif and Floresta basin in the axial Eastern Cordillera of Colombia suggest major Paleogene shortening in a ramp-flat fold-thrust belt. Field mapping indicates that the hanging wall of the east-directed Soápaga fault system contains a series of upright thrust sheets with flat-on-flat cutoff relationships and a deformed footwall characterized by a complex triangle zone. These geometries necessitate roughly east-west shortening exceeding that of a previously mapped overturned hanging wall anticline and disharmonic footwall folds. Zircon (U-Th)/He (ZHe) ages indicate exhumation-induced cooling of the Soápaga hanging wall through the ˜180 °C closure temperature at 31-25 Ma. This cooling postdated documented shortening to the west and predated shortening to the east, suggesting an eastward progression of Paleogene deformation. Synorogenic Oligocene footwall strata of the Floresta basin contain distal fine-grained sediments and lack growth strata or Oligocene detrital ZHe ages, suggesting relatively high heave along the Soápaga fault system. These results are consistent with a rapidly eastward-propagating, basement-involved fold-thrust belt with ramp-flat structures that accommodated tens of km of shortening. Long-term stasis of the deformation front on the eastern and western flanks of the Eastern Cordillera due to localization of Neogene shortening along Mesozoic rift-bounding normal faults indicates a shift in deformational style in late Oligocene-early Miocene time. This geometric and temporal framework implies: 1) a total shortening in the northern Andes exceeding most current estimates; 2) Paleogene deformation in the Eastern Cordillera marked by rapid advances of the deformation front along a ramp-flat thrust system; and 3) focused Neogene reactivation (inversion) of master rift

  3. Structural studies of TiO2/wood coatings prepared by hydrothermal deposition of rutile particles from TiCl4 aqueous solutions on spruce (Picea Abies) wood

    NASA Astrophysics Data System (ADS)

    Pori, Pavel; Vilčnik, Aljaž; Petrič, Marko; Sever Škapin, Andrijana; Mihelčič, Mohor; Šurca Vuk, Angela; Novak, Urban; Orel, Boris

    2016-05-01

    A low temperature approach was developed for the deposition of rutile TiO2 particles on a wood surface by hydrolysis of TiCl4 in aqueous solutions acidified with HCl, and crystallization at 75 and 90 °C (1 h). Prior to hydrothermal treatment, Picea Abies wood was first soaked in a 0.5 mmol/l aqueous solution containing anionic surfactant sodium dodecyl sulphate (SDS, Sigma Aldrich) for 2 h at 80 °C. The crystal structure of the hydrothermally made rutile particles was determined with XRD, while the morphology of the deposited TiO2 particles and their distribution in the wood were examined with SEM and EDX measurements. The penetration and amount of deposited rutile particles could be modified by changing the deposition conditions. Thicker layers were obtained from more concentrated aqueous TiCl4 solutions with and without added HCl, and with longer deposition times and higher temperatures of the hydrothermal treatment. The interaction of TiO2 particles with hemicellulose and lignin in wood was established from infrared attenuated total reflection (FT-IR ATR) and Raman spectra measurements, from which the spectra of wood were subtracted. Analysis of the subtraction spectra showed the presence of titania particles on the wood surface, revealing also the establishment of TiO2-wood coordinative bonds of titanium ions with hemicellulose and lignin. The red frequency shift of the OH stretching modes suggested interaction of the TiO2 particles with water molecules of wood. TiO2 deposited on wood treated with SDS became hydrophobic (water contact angles (WCA) of 150°), contrasting the properties of untreated wood with a deposited TiO2 particle coating, which remained hydrophilic.

  4. Patterns of population structure for inshore bottlenose dolphins along the eastern United States.

    PubMed

    Richards, Vincent P; Greig, Thomas W; Fair, Patricia A; McCulloch, Stephen D; Politz, Christine; Natoli, Ada; Driscoll, Carlos A; Hoelzel, A Rus; David, Victor; Bossart, Gregory D; Lopez, Jose V

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline.

  5. Patterns of Population Structure for Inshore Bottlenose Dolphins along the Eastern United States

    PubMed Central

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline. PMID:24129993

  6. Carbon sequestration by young Norway spruce monoculture

    NASA Astrophysics Data System (ADS)

    Pokorny, R.; Rajsnerova, P.; Kubásek, J.

    2012-04-01

    Many studies have been focused on allometry, wood-mass inventory, carbon (C) sequestration, and biomass expansion factors as the first step for the evaluation of C sinks of different plant ecosystems. To identify and quantify these terrestrial C sinks, and evaluate CO2 human-induced emissions on the other hand, information for C balance accounting (for impletion of commitment to Kyoto protocol) are currently highly needed. Temperate forest ecosystems have recently been identified as important C sink. Carbon sink might be associated with environmental changes (elevated [CO2], air temperature, N deposition etc.) and large areas of managed fast-growing young forests. Norway spruce (Pice abies L. Karst) is the dominant tree species (35%) in Central European forests. It covers 55 % of the total forested area in the Czech Republic, mostly at high altitudes. In this contribution we present C sequestration by young (30-35 year-old) Norway spruce monocultures in highland (650-700 m a.s.l., AT- mean annual temperature: 6.9 ° C; P- annual amount of precipitation: 700 mm; GL- growing season duration: 150 days) and mountain (850-900 m a.s.l.; AT of 5.5 ° C; P of 1300 mm; and GL of 120 days) areas and an effect of a different type of thinning. However, the similar stem diameter at the breast height and biomass proportions among above-ground tree organs were obtained in the both localities; the trees highly differ in their height, above-ground organ's biomass values and total above ground biomass, particularly in stem. On the total mean tree biomass needle, branch and stem biomass participated by 22 %, 24 % and 54 % in highland, and by 19 %, 23 % and 58 % in mountain area, respectively. Silvicultural management affects mainly structure, density, and tree species composition of the stand. Therefore, dendrometric parameters of a tree resulted from genotype, growth conditions and from management history as well. Low type of thinning (LT; common in highland) stimulates rather tree

  7. Intra-annual variability of anatomical structure and delta(13)C values within tree rings of spruce and pine in alpine, temperate and boreal Europe.

    PubMed

    Vaganov, Eugene A; Schulze, Ernst-Detlef; Skomarkova, Marina V; Knohl, Alexander; Brand, Willi A; Roscher, Christiane

    2009-10-01

    Tree-ring width, wood density, anatomical structure and (13)C/(12)C ratios expressed as delta(13)C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, delta(13)C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, cell-wall thickness, cell-wall area and cell-lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained <20% of the variation in tree-ring width and wood density over consecutive years, while 29-58% of the variation in tree-ring width were explained by autocorrelation between tree rings. An intensive study of tree rings between 1999 and 2003 revealed that tree ring width and delta(13)C-values of whole wood were significantly correlated with length of the growing season, net radiation and vapor pressure deficit. The delta(13)C-values were not correlated with precipitation or temperature. A highly significant correlation was also found between delta(13)C of the early wood of one year and the late wood of the previous year, indicating a carry-over effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the delta(13)C between late wood and early wood. The results are interpreted in the context of the biochemistry

  8. Intra-annual variability of anatomical structure and δ13C values within tree rings of spruce and pine in alpine, temperate and boreal Europe

    PubMed Central

    Vaganov, Eugene A.; Skomarkova, Marina V.; Knohl, Alexander; Brand, Willi A.; Roscher, Christiane

    2009-01-01

    Tree-ring width, wood density, anatomical structure and 13C/12C ratios expressed as δ13C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, δ13C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, cell-wall thickness, cell-wall area and cell-lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained <20% of the variation in tree-ring width and wood density over consecutive years, while 29–58% of the variation in tree-ring width were explained by autocorrelation between tree rings. An intensive study of tree rings between 1999 and 2003 revealed that tree ring width and δ13C-values of whole wood were significantly correlated with length of the growing season, net radiation and vapor pressure deficit. The δ13C-values were not correlated with precipitation or temperature. A highly significant correlation was also found between δ13C of the early wood of one year and the late wood of the previous year, indicating a carry-over effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the δ13C between late wood and early wood. The results are interpreted in the context of the biochemistry of wood formation and its linkage

  9. Climate-mediated changes in zooplankton community structure for the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Eisner, Lisa B.; Napp, Jeffrey M.; Mier, Kathryn L.; Pinchuk, Alexei I.; Andrews, Alexander G.

    2014-11-01

    Zooplankton are critical to energy transfer between higher and lower trophic levels in the eastern Bering Sea ecosystem. Previous studies from the southeastern Bering Sea shelf documented substantial differences in zooplankton taxa in the Middle and Inner Shelf Domains between warm and cold years. Our investigation expands this analysis into the northern Bering Sea and the south Outer Domain, looking at zooplankton community structure during a period of climate-mediated, large-scale change. Elevated air temperatures in the early 2000s resulted in regional warming and low sea-ice extent in the southern shelf whereas the late 2000s were characterized by cold winters, extensive spring sea ice, and a well-developed pool of cold water over the entire Middle Domain. The abundance of large zooplankton taxa such as Calanus spp. (C. marshallae and C. glacialis), and Parasagitta elegans, increased from warm to cold periods, while the abundance of gelatinous zooplankton (Cnidaria) and small taxa decreased. Biomass followed the same trends as abundance, except that the biomass of small taxa in the southeastern Bering Sea remained constant due to changes in abundance of small copepod taxa (increases in Acartia spp. and Pseudocalanus spp. and decreases in Oithona spp.). Statistically significant changes in zooplankton community structure and individual species were greatest in the Middle Domain, but were evident in all shelf domains, and in both the northern and southern portions of the eastern shelf. Changes in community structure did not occur abruptly during the transition from warm to cold, but seemed to begin gradually and build as the influence of the sea ice and cold water temperatures persisted. The change occurred one year earlier in the northern than the southern Middle Shelf. These and previous observations demonstrate that lower trophic levels within the eastern Bering Sea respond to climate-mediated changes on a variety of time scales, including those shorter than

  10. Shallow crustal structure of eastern-central Trans-Mexican Volcanic Belt.

    NASA Astrophysics Data System (ADS)

    Campos-Enriquez, J. O.; Ramón, V. M.; Lermo-Samaniego, J.

    2015-12-01

    Central-eastern Trans-Mexican Volcanic Belt (TMVB) is featured by large basins (i.e., Toluca, Mexico, Puebla-Tlaxcala, Libres-Oriental). It has been supposed that major crustal faults limit these basins. Sierra de Las Cruces range separates the Toluca and Mexico basins. The Sierra Nevada range separates Mexico basin from the Puebla-Tlaxcala basin. Based in gravity and seismic data we inferred the Toluca basin is constituted by the Ixtlahuaca sub-basin, to the north, and the Toluca sub-basin to the south, which are separated by a relative structural high. The Toluca depression is more symmetric and bounded by sub-vertical faults. In particular its eastern master fault controlled the emplacement of Sierra de Las Cruces range. Easternmost Acambay graben constitutes the northern and deepest part of the Ixtlahuaca depression. The Toluca-Ixtlahuaca basin is inside the Taxco-San Miguel de Allende fault system, and limited to the west by the Guerrero terrane which continues beneath the TMVB up to the Acambay graben. Mexico basin basement occupies an intermediate position and featured by a relative structural high to the north-east, as established by previous studies. This relative structural high is limited to the west by the north-south Mixhuca trough, while to the south it is bounded by the east-west Copilco-Xochimilco-Chalco sub-basin. The Puebla-Tlaxcala basin basement is the shallowest of these 3 tectonic depressions. In general, features (i.e., depth) and relationship between these basins, from west to east, are controlled by the regional behavior of the Sierra Madre Oriental fold and thrust belt basement (i.e., Oaxaca Complex?). This study indicates that an active east-west regional fault system limits to the south the TMVB (from the Nevado de Toluca volcano through the Popocatepetl volcano and eastward along southern Puebla-Tlaxcala basin). The Tenango and La Pera fault systems constituting the western part of this regional fault system coincide with northern

  11. Lenticular stretch structures in eastern Nevada - possible trapping mechanism in supposed graben

    SciTech Connect

    Walker, C.T.; Dennis, J.G.; Lumsden, W.W.

    1986-04-01

    Eastern Nevada is widely recognized as a region of tectonic extension. The dominant structures are generally agreed to be low-dipping, younger over older faults and steeper listric faults that are responsible for the basins (grabens) and ranges (horsts). In the Schell Creek-Duck Creek Range, east of Ely, and in the White Pine Range, southwest of Ely, small lenticular structures bounded by tectonic discontinuities can be clearly seen in the field. These lenticular units, or stretch structures, range in length from a few meters to more than 200 m. All lenticular stretch structures that can be clearly seen in the field are stratigraphically restricted; the stretched formations are the Eureka Quartzite, the Pilot Shale, the Joana Limestone, and the Chainman Shale. Still larger stretch structures, which may include several formations, are inferred, and the authors suggest that extension has created lenticular structures at all scales. The Duck Creek and Schell Creek Ranges east of Ely consist mostly of Devonian and older rocks. They are separated by a topographically lower area containing mostly Mississippian and Pennsylvanian rocks. This structure, which separates the ranges, has been referred to as a graben, but field evidence suggests that it is a large-scale lenticular stretch structure. Unlike a true graben, the structure does not extend downward. For example, in several places within the supposed graben, Cambrian and Ordovician rocks project through a cover of Carboniferous Chainman Shale and Ely Limestone, suggesting the Chainman-Ely is a thin sheet underlain by Cambrian-Ordovician rocks. Accordingly, they suggest that extension in the Duck Creek-Schell Creek Ranges stretched the formations into lenticular bodies. Between the Duck Creek and Schell Creek Ranges, the Cambrian-Ordovician is attenuated, and the resulting tectonic depression is occupied by a lenticular mass of Carboniferous rocks.

  12. Structure of the lithosphere beneath the Eastern Alps (southern sector of the TRANSALP transect)

    NASA Astrophysics Data System (ADS)

    Castellarin, Alberto; Nicolich, Rinaldo; Fantoni, Roberto; Cantelli, Luigi; Sella, Mattia; Selli, Luigi

    2006-02-01

    supported by any significant uplifting of the Dolomites. The total average uplift of the Dolomites during the Neogene appears to be 6-7 times smaller than that recognized in the TW. Markedly the northward dip of the PL, reaching a depth of approximately 20 km, is proposed in our interpretation; finally, the Adriatic upper crustal evolution points to the late post-collision change in the tectonic grow-up of the Eastern Alps orogenic chain. The tectonic accretion of the northern frontal zone of the Eastern and Central Alps was interrupted from the Late Miocene (Serravallian-Tortonian) onward, as documented by the Molasse basin evolution. On the contrary, the structural nucleation along the S-vergent tectonic belt of the eastern Southern Alps ( Montello-Friuli thrust belt) severely continued during the Messinian and the Plio-Pleistocene. This structural evolution can be considered to be consistent with the deep under-thrusting and wedge indentation of the Adriatic lithosphere underneath the southern side of the Eastern Alps thrust-and-fold belt. Similarly, the significance of the magmatic activity for the construction of the Southern Alps crust and for its mechanical and geological differentiation, which qualified the evolution of the thrust-and-fold belt, is highlighted, starting with the Permian-Triassic magmatism and progressing with the Paleogene occurrences along the Periadriatic Lineament and in the Venetian Magmatic Province (Lessini-Euganei Hills).

  13. Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

    PubMed Central

    Malyarenko, Timofey V.; Malyarenko (Vishchuk), Olesya S.; Ivanchina, Natalia V.; Kalinovsky, Anatoly I.; Popov, Roman S.; Kicha, Alla A.

    2015-01-01

    Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway. PMID:26193286

  14. Seismic imaging of shallow reflectors in the eastern Kapuskasing structural zone, with correction of crossdip attitudes

    NASA Astrophysics Data System (ADS)

    Kim, Jisoo; Moon, Wooil M.; Percival, John A.; West, F. G.

    1992-10-01

    Cascaded processes of crossdip correction and residual statics are tested and applied in the reprocessing of regional data from LITHOPROBE Kapuskasing Transect line 2. The objective was to improve seismic imaging of shallow, gently dipping reflectors in the eastern Kapuskasing structural zone, a thrusted slice of Archean middle to lower crust. This focusing strategy proved to be very effective in improving the image of the reflected energy and in identifying a set of conformally dipping reflectors whose true crossdip is estimated to be approximately 17 deg NW. The estimated crossdip for a reflective, compositionally layered zone and for the basal thrust, the Ivanhoe Lake Fault zone, support the previously estimated average dip of 15-20 deg.

  15. Compositional and structural constraints on the geologic history of eastern Tharsis Rise, Mars

    NASA Astrophysics Data System (ADS)

    Viviano-Beck, C. E.; Murchie, S. L.; Beck, A. W.; Dohm, J. M.

    2017-03-01

    Identification and mapping of distinct compositional units using high-resolution orbital imagery of the walls of Valles Marineris, Mars, provide key structural and environmental constraints on the geologic history of the eastern Tharsis Rise. Our results corroborate an overall vertical structure of the upper crust consistent with that inferred from previous studies. An upper unit spectrally consistent with basalt that has variable thickness is overlain on an early to possibly pre-Noachian substrate. The pre-/early-Noachian material is heterogeneous, dominated by low-calcium pyroxene-rich material but ranging locally from feldspathic to and olivine-rich. Aqueous alteration of pre-/early-Noachian rock to dominantly Fe/Mg-smectite is widespread and observed along the chasma walls from -4 to 1 km. However phyllosilicates outcrop discontinuously, suggesting that they were emplaced via impact excavation of even older altered material, or formed by non-uniform alteration driven by impact- or magma-related hydrothermal activity. A distinct, higher-temperature alteration assemblage identified by the presence of chlorite, zeolite, and associated carbonate (+/-serpentine) occurs on both the north and south walls of eastern Coprates Chasma in a confined longitudinal band, where the eastern margin of the Thaumasia Plateau intersects Valles Marineris. These secondary minerals are concentrated within a heavily fractured band exposed at a regional tectonic boundary along the margin of the Thaumasia Plateau, and likely record a regional zone of elevated crustal heat flow and fluid circulation. The generally north-south trending band exhibiting this distinct assemblage serves as a tracer for tectonic deformation; its continuity across Valles Marineris is incongruous with previously suggested lateral slip along the margin of a 'megaslide', and constrains left-lateral transtensional faulting to less than ∼25-50 km. Mapping of compositionally distinct outcrops to the west also

  16. Third year effects of cloudwater and ozone on red spruce seedlings

    SciTech Connect

    Pier, P.A.; Thornton, F.C.; McDuffie, C. Jr. )

    1991-05-01

    The reduction in growth of high elevation red spruce in the eastern US has been attributed in part to greater exposure to atmospheric pollution which occurs at high elevation. The authors objective was to evaluate the impact of ambient ozone and cloudwater deposition on the growth of red spruce seedlings at a high elevation site. Potted native and Phyton-grown (Phyton Technologies) red spruce seedlings were exposed in open-top field chambers at Whitetop Mountain, Virginia (elevation 1,680) for the third season to treatments of: (1) exclusion of clouds and 50% reduction in ambient O{sub 3} (COE), (2) O{sub 3} with clouds excluded (CO), (3) exposure to clouds and O{sub 3}, as control chambers (CC), and (4) open plots (AA). Plant biomass components and diameter increment growth for both seedling types were not affected by treatments. Photosynthesis was not enhanced by removal of cloudwater and O{sub 3}. Respiration (R{sub d}) generally was not affected by treatments; however, R{sub d} in native seedling needles of previous year and two-year previous growth was significantly greater in CC than CO and COE on several sampling dates, indicating that cloudwater and O{sub 3} may be causing higher R{sub d}.

  17. Structural and petrologic evolution of the Lihue basin and eastern Kauai, Hawaii

    USGS Publications Warehouse

    Reiners, P.W.; Nelson, B.K.; Izuka, S.K.

    1999-01-01

    The topography of the eastern part of the Hawaiian island of Kauai is dominated by the Lihue basin, a large (???110 km2) semicircular depression bounded by steep cliffs and partly filled by late rejuvenated-stage (or post-erosional stage) volcanic material. As with other large, semicircular basins on ocean-island volcanoes, the subsurface geology and origin (e.g., structural collapse vs. fluvial erosion) of the Lihue basin are poorly understood. New analyses of samples collected from eastern Kauai and drill holes within the basin document several important features of the late-stage geologic evolution of Kauai. First, thick (>300 m) sequences of rejuvenated-stage Koloa Volcanics in the Lihue basin show systematic, basin-wide geochemical trends of increasingly incompatible elements with time, indicating a gradual decrease in the extent of partial melting of mantle sources with time. Second, beneath the rejuvenated-stage volcanics in the basin, a thin layer of postshield alkalic stage lavas (e.g., hawaiites and mugearites) overlies older shield-stage tholeiitic lavas of the Napali Member, indicating that the Lihue basin formed by structural collapse, not fluvial erosion. Third, a large (???2-5 km3) matrix-supported breccia, interpreted as deposits of one or more debris flows, is within the rejuvenated-stage volcanics throughout the basin, and correlates with surficial exposures of the Palikea Breccia west of the basin. Isotopic compositions of the bulk breccia are similar to those of tholeiites from the east side of Kauai, and distinct from those of west Kauai tholeiites. Clasts within the breccia are dominantly hawaiite and alkali gabbro. The source region of the breccia in the steep cliffs and highlands of the central massif to the west of the basin must contain magmatic products of an extensive postshield alkalic stage, including hawaiite flows and one or more large intrusive bodies or ponded sequences of alkali gabbro.

  18. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales.

    PubMed

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M; Kinze, Carl; Lockyer, Christina H; Vighi, Morgana; Aguilar, Alex

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ(18)O) in the inorganic component (hydroxyapatite), and nitrogen and carbon isotope ratios (δ(15)N: δ(13)C) in the organic component (primarily collagenous). We found significant differences between Denmark and NW Spain in δ(15)N and δ(18)O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ(15)N, δ(13)C and δ(18)O values in the period up to age 20, and in the ontogenetic variation of δ(15)N and δ(18)O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted.

  19. Crustal structure of the Central-Eastern Greenland: results from the TopoGreenland refraction profile

    NASA Astrophysics Data System (ADS)

    Shulgin, Alexey; Thybo, Hans

    2014-05-01

    Until present, seismic surveys have only been carried out offshore and near the coasts of Greenland, where the crustal structure is affected by oceanic break-up. We present the deep seismic structure of the crust of the interior of Greenland, based on the new and the only existing so far seismic refraction/wide-angle reflection profile. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass, made acquisition of geophysical data logistically complicated. The profile extends 310 km inland in E-W direction from the approximate edge of the stable ice cap near the Scoresby Sund across the center of the ice cap. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 125 kg at 35-85 m depth in individual boreholes. Given that the data acquisition was affected by the thick ice sheet, we questioned the quality of seismic records in such experiment setup. We have developed an automatic routine to check the amplitudes and spectra of the selected seismic phases and to check the differences/challenges in making seismic experiments on ice and the effects of ice on data interpretation. Using tomographic inversion and forward ray tracing modelling we have obtained the two-dimensional velocity model down to a 50 km depth. The model shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western part of the profile to 40 km in its eastern part. Relatively high lower crustal velocities (Vp 6.8 - 7.3 km/s) in the western part of the TopoGreenland profile may result from past collision tectonics or, alternatively, may be related to the speculated passage of the Iceland mantle plume. Comparison of our results

  20. Geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Texas

    USGS Publications Warehouse

    Clark, Allan K.; Pedraza, Diana E.; Morris, Robert R.

    2013-01-01

    By using data that were compiled and collected for this study and previous studies, a revised map was constructed depicting the geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Tex. The map also shows the interpreted structural dip directions and interpreted location of a structural low (trough) in the area known as the Knippa Gap.

  1. Lithospheric structure beneath Eastern Africa from joint inversion of receiver functions and Rayleigh wave velocities

    NASA Astrophysics Data System (ADS)

    Dugda, Mulugeta Tuji

    Crust and upper mantle structure beneath eastern Africa has been investigated using receiver functions and surface wave dispersion measurements to understand the impact of the hotspot tectonism found there on the lithospheric structure of the region. In the first part of this thesis, I applied H-kappa stacking of receiver functions, and a joint inversion of receiver functions and Rayleigh wave group velocities to determine the crustal parameters under Djibouti. The two methods give consistent results. The crust beneath the GEOSCOPE station ATD has a thickness of 23+/-1.5 km and a Poisson's ratio of 0.31+/-0.02. Previous studies give crustal thickness beneath Djibouti to be between 8 and 10 km. I found it necessary to reinterprete refraction profiles for Djibouti from a previous study. The crustal structure obtained for ATD is similar to adjacent crustal structure in many other parts of central and eastern Afar. The high Poisson's ratio and Vp throughout most of the crust indicate a mafic composition, suggesting that the crust in Afar consists predominantly of new igneous rock emplaced during the late synrift stage where extension is accommodated within magmatic segments by diking. In the second part of this thesis, the seismic velocity structure of the crust and upper mantle beneath Ethiopia and Djibouti has been investigated by jointly inverting receiver functions and Rayleigh wave group velocities to obtain new constraints on the thermal structure of the lithosphere. Crustal structure from the joint inversion for Ethiopia and Djibouti is similar to previously published models. Beneath the Main Ethiopian Rift (MER) and Afar, the lithospheric mantle has a maximum shear wave velocity of 4.1-4.2 km/s and extends to a depth of at most 50 km. In comparison to the lithosphere away from the East African Rift System in Tanzania, where the lid extends to depths of ˜100-125 km and has a maximum shear velocity of 4.6 km/s, the mantle lithosphere under the Ethiopian Plateau

  2. Cloning and characterization of a Gasp homolog from the spruce budworm, Choristoneura fumiferana, and its putative role in cuticle formation.

    PubMed

    Nisole, A; Stewart, D; Bowman, S; Zhang, D; Krell, P J; Doucet, D; Cusson, M

    2010-10-01

    Proteins that are capable of binding chitin play essential roles in the synthesis and structural integrity of the insect cuticle and peritrophic matrix. In the course of developing expressed sequence tag (EST) libraries for the eastern spruce budworm, Choristoneura fumiferana, we identified an abundant cDNA encoding a homolog of the Drosophila "gasp" gene (Gene Analogous to Small Peritrophins). For the present work, we undertook the characterization of this new homolog, CfGasp, in an effort to identify its role during larval development. As shown for DmGasp, the C. fumiferana homolog was found to contain three type-2 chitin-binding domains (CBDs), which were also found in Gasp orthologs retrieved from GenBank. In a phylogenetic analysis, these Gasp proteins formed a tight cluster, distinct from the midgut-specific peritrophins with which they share the cysteine-containing CBDs so far considered absent from cuticular proteins. However, unlike what has been shown for peritrophins, CfGasp transcript levels were low in larval midguts and most abundant in epidermis, while they were low in trachea and ovaries. Transcript levels increased during larval molts in a pattern similar to that observed for exocuticular proteins in other insects. In addition, the recombinant protein was shown to be capable of binding chitin. Altogether, these results suggest a structural role for CfGasp in exocuticle formation.

  3. Structural pattern and emplacement mechanism of the Neka Valley nappe complex, eastern Alborz, Iran

    NASA Astrophysics Data System (ADS)

    Nabavi, Seyed Tohid; Rahimi-Chakdel, Aziz; Khademi, Mohsen

    2016-12-01

    The Neka Valley nappe complex is exposed in the south of Gorgan County in the eastern Alborz fold-and-thrust belt. We use the results of a regional survey of the structural data and their patterns to interpret the mechanisms that emplaced the unmetamorphosed nappes in the foreland fold-and-thrust belt of the Alborz Mountains. Most of the strain magnitudes are low in the study area but increase slightly towards what are probably their proximal ends. Strain ellipsoid is dominantly oblate with XY aligned along and across the belt (or the nappe complex). The average kinematic vorticity number, W k = 0.6 which indicates most of the strain partitioning resulted in a general shear. Most of Flinn's k values and α (the stretch along the shear plane) values are lower than 1. Structural indicators such as orthogonal extensional joints, pinch-and-swell structures, anastomosing cleavages, and listric normal and growth faults developed by push from the rear. Large-scale thrust complexes with opposed-dips such as triangle zones (as well as k and α-values <1) are compatible with the shear flow diverging distally and streamlines expected of the rear compression emplacement mechanism. Together with a later minor brittle deformation, these major ductile strains appears to provide a general model suitable for the emplacement of the nappes studied in a thin-skinned fold-and-thrust belt where the sedimentary cover strata shortened and imbricated in the upper crust.

  4. The structure of the Africa-Anatolia plate boundary in the eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Vidal, Neus; Alvarez-Marrón, Joaquina; Klaeschen, Dirk

    2000-08-01

    New marine deep seismic reflection data from south of Cyprus to the Syrian coast provide images of the upper crustal structure of the Cyprean Arc indicating that the deformation is partitioned along strike-slip fault systems distributed over a wide zone, rather than forming a sharp plate boundary between African and Anatolian plates. Three major submarine strike-slip fault systems, tens of kilometers in length, are mapped, which follow bathymetric features and merge together toward the east. These structures exhibit the three-dimensional characteristics typical of strike-slip deformation zones throughout the seven pre-stack depth-migrated sections, including several sets of positive flower structures forming bathymetric ridges, and the intervening contemporaneous subbasins. Beneath the Plio-Quaternary sediments (500 m thick) that are blanketing the whole area and that reflect only the main surface traces of the fault systems, the subbasins are of varied dimensions and have rapid lateral changes in the thickness of the sedimentary fill. They include two major unconformities that have been correlated throughout the data marked by the M and K reflections. The M reflection is well imaged above varied thickness of Messinian evaporites, and the K reflection commonly appears at the base of syntectonic Tertiary age sediments. Within the eastern Cyprean Arc the K reflection corresponds to the basement-cover contact, indicating that the strike-slip tectonic scenario may have been active since the uppermost Cretaceous or lowermost Paleogene times to present. The active deformation front of the Alpine belt in the eastern Mediterranean corresponds to a strike-slip fault system that forms a 110° arc and coincides at the southern slope of the Hecateaus Rise, continuing along the Latakia Ridge to the Syrian coast. The mapped structures fit within a general kinematic framework of left-lateral transcurrent deformation that transfers slip from the subduction zone southwest of Cyprus

  5. Boreal peatland margins as repository sites of long-term natural disturbances of balsam fir/spruce forests

    NASA Astrophysics Data System (ADS)

    Lavoie, Martin; Filion, Louise; Robert, Élisabeth C.

    2009-05-01

    A multidisciplinary, high-resolution paleoecological study (Lepidoptera and plant remains, macroscopic charcoal, pollen) was conducted on a 4000-yr peat monolith extracted from the margin of an ombrotrophic peatland on Anticosti Island (Gulf of St. Lawrence, eastern Canada) to reconstruct the long-term natural disturbances (insect outbreaks, forest fires) of a balsam fir/spruce forest. We hypothesized that an activity of insect defoliators (spruce budworm, hemlock looper) was the main disturbance factor of conifer forests during the Late Holocene. The earliest remains of spruce budworm and hemlock looper were found ca. 3220 and 2350 cal yr BP, respectively. Peaks of insect head capsules occurred from ca. 1640 to ca. 625 cal yr BP. Low balsam fir pollen concentrations during this period suggest a lengthy episode (˜ 1000 yr) of high insect activity, resulting in extensive fir dieback and mortality. The long-term dynamics of the pristine balsam fir/spruce forests were mainly governed by the activity of insect defoliators. The limited extent and possibly the low occurrence of forest fires in the maritime environment of Anticosti Island allowed the development of mature coniferous stands propitious for insect infestations. Insect head capsules appeared to be a useful and effective tool for establishing insect presence and activity during the Holocene.

  6. Trophic size-structure of sailfish Istiophorus platypterus in eastern Taiwan estimated by stable isotope analysis.

    PubMed

    Tsai, C-N; Chiang, W-C; Sun, C-L; Shao, K-T; Chen, S-Y; Yeh, S-Z

    2014-02-01

    To examine trophic dynamics over different size classes, an isotopic study of sailfish Istiophorus platypterus life-history stages was carried out. Samples were collected from eastern Taiwan and the South China Sea during April 2009 and February 2012. A total of 263 samples (111-245 cm, lower jaw fork length, LLJFL ) were examined for changes in trophic structure in relation to LLJFL by using stable isotope analysis of carbon (δ(13) C) and nitrogen (δ(15) N). The δ(15) N values for I. platypterus ranged from 7·51 to 14·19‰ (mean ± s.d. = 12·06 ± 1·16‰) and the δ(13) C values ranged from -22·04 to -15·48‰ (mean ± s.d. = -17·62 ± 1·10‰). The δ(15) N values were positively dependent on LLJFL (r(2)  = 0·377), whereas δ(13) C were negatively dependent on LLJFL (r(2)  = 0·063). There were significantly different seasonal changes in nitrogen and carbon isotopic concentration, but no significant differences in concentrations between eastern Taiwan and the South China Sea were reported. The trophic level (TL ) of each LLJFL class was correlated, starting from 2·84 TL for size class I (LLJFL  < 140 cm) and reaching 5·03 TL for size class VI (LLJFL > 221 cm). The mean ± s.d. TL was 4·43 ± 0·19 for all samples. The results reveal that I. platypterus occupies a wide range of trophic levels and different size classes occupy different trophic positions in the pelagic ecosystem.

  7. Stem analysis of a long-lived black spruce clone at treeline

    SciTech Connect

    Payette, S.; Delwaide, A.; Morneau, C.; Lavoie, C. )

    1994-02-01

    Because of its ability to layer and to produce different phenotypes, black spruce (Picea mariana [Mill.] BSP.) develops a complex clonal structure ensuring its survival and longevity. Here we report tree stem development and demise of a black spruce clone at treeline over the last 500 yr. Since the 16th century, the apical meristems of the clonal spruce experienced three periods of stem development associated with brief warmings and two periods of stem decline corresponding to known cold spells of the Little Ice Age. Ortet development was particularly vigorous in the 16th century, while the two layered stems slowly developed in the late 17th century and in the 20th century, respectively. Stem decline appeared as a progressive process lasting for several decades in the form of a basipetal death-gradient along the bole amplified by the above/below snow-pack position. Stem elongation was possibly facilitated by lesser winter-snow abrasion and/or thicker snowpack. Clonal stem development may have important implications for spruce spread in the arctic tundra in a warmer world. 26 refs. 2 figs.

  8. The uppermost mantle shear wave velocity structure of eastern Africa from Rayleigh wave tomography: constraints on rift evolution

    NASA Astrophysics Data System (ADS)

    O'Donnell, J. P.; Adams, A.; Nyblade, A. A.; Mulibo, G. D.; Tugume, F.

    2013-08-01

    An expanded model of the 3-D shear wave velocity structure of the uppermost mantle beneath eastern Africa has been developed using earthquakes recorded by the AfricaArray East African Seismic Experiment in conjunction with data from permanent stations and previously deployed temporary stations. The combined data set comprises 331 earthquakes recorded on a total of 95 seismic stations spanning Kenya, Uganda, Tanzania, Zambia and Malawi. In this study, data from 149 earthquakes were used to determine fundamental-mode Rayleigh wave phase velocities at periods ranging from 20 to 182 s using the two-plane wave method, and then combined with the similarly processed published measurements and inverted for a 3-D shear wave velocity model of the uppermost mantle. New features in the model include (1) a low-velocity region in western Zambia, (2) a high-velocity region in eastern Zambia, (3) a low-velocity region in eastern Tanzania and (4) low-velocity regions beneath the Lake Malawi rift. When considered in conjunction with mapped seismicity, these results support a secondary western rift branch striking southwestwards from Lake Tanganyika, likely exploiting the relatively weak lithosphere of the southern Kibaran Belt between the Bangweulu Block and the Congo Craton. We estimate a lithospheric thickness of ˜150-200 km for the substantial fast shear wave anomaly imaged in eastern Zambia, which may be a southward subsurface extension of the Bangweulu Block. The low-velocity region in eastern Tanzania suggests that the eastern rift branch trends southeastwards offshore eastern Tanzania coincident with the purported location of the northern margin of the proposed Ruvuma microplate. Pronounced velocity lows along the Lake Malawi rift are found beneath the northern and southern ends of the lake, but not beneath the central portion of the lake.

  9. On the formation of lignin polysaccharide networks in Norway spruce.

    PubMed

    Oinonen, Petri; Zhang, Liming; Lawoko, Martin; Henriksson, Gunnar

    2015-03-01

    In this study we were mirroring suggested in vivo phenomena of lignin-hemicellulose complex formation in vitro, by cross-linking Norway spruce (Picea abies) galactoglucomannans, xylans and lignin moieties to high molecular weight complexes by laccase treatment. We were able to observe the oxidation and cross-linking of non-condensed guaiacyl-type phenolic moieties attached to both of the hemicelluloses by (31)P NMR and size-exclusion chromatography. We suggest that hemicelluloses-lignin complexes form covalently linked structural units during the early stages of lignification via radical enzymatic cross-linking catalyzed by laccase. This work shows that the hemicellulose molecules in wood are covalently linked to two or more lignin units thereby making them suited for forming network structures.

  10. Top or Bottom-Heavy? Observational Constraints on the Vertical Structure of the Eastern Pacific ITCZ

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Huaman, L.

    2015-12-01

    The Intertropical Convergence Zone (ITCZ) is a key component of the eastern Pacific ocean-atmosphere system and its variability on seasonal to inter-annual and longer time scales. This feature is generally misrepresented in climate models, which show an excessively strong branch south of the equator. On the other hand, there is debate on what is the structure of the ITCZ in nature, particularly whether the latent heating and vertical velocity profiles are top or bottom-heavy. This knowledge is probably key to validate and improve the models. Most methods for estimating the vertical structure of the rate of latent heating
rely on profiles from field campaigns in other regions, combined with convective/stratiform fractions from the TRMM satellite.
In this study we use the precipitation profiles from the TRMM Precipitation Radar (PR), with approximations to the moisture conservation equation and the first law of thermodynamic, to directly estimate the vertical profiles of latent heating and vertical air velocity, respectively, in the ITCZ for the period 1998-2010. Due to limitations in the PR sensitivity and the inability to quantify solid precipitation, our results are restricted to the layer between the altitudes of 2 and 2.75 km. Nevertheless, we show that our results provide a strong constraint on the profiles and help determine which of the other estimates are more realistic. Our preliminary results for the northern hemisphere ITCZ in austral winter/spring are closer to the top-heavy estimations using TRMM-based algorithms (CSH, SLH and PRH) than to the bottom-heavy atmospheric reanalysis (ERA Interim and NCEP-NCAR), providing indirect evidence for a top-heavy profile. However, using the meridional wind measurements during the EPIC field campaign we find evidence that shallow ascent does exist below 2 km, consistent with the previously reported shallow meridional circulation but not as strong as the Reanalysis products indicate. Thus, our results support the

  11. Insights into Symbiont Population Structure among Three Vestimentiferan Tubeworm Host Species at Eastern Pacific Spreading Centers

    PubMed Central

    Juniper, S. Kim

    2016-01-01

    ABSTRACT The symbiotic relationship between vestimentiferan tubeworms and their intracellular chemosynthetic bacteria is one of the more noteworthy examples of adaptation to deep-sea hydrothermal vent environments. The tubeworm symbionts have never been cultured in the laboratory. Nucleotide sequences from the small subunit rRNA gene suggest that the intracellular symbionts of the eastern Pacific vent tubeworms Oasisia alvinae, Riftia pachyptila, Tevnia jerichonana, and Ridgeia piscesae belong to the same phylotype of gammaproteobacteria, “Candidatus Endoriftia persephone.” Comparisons of symbiont genomes between the East Pacific Rise tubeworms R. pachyptila and T. jerichonana confirmed that these two hosts share the same symbionts. Two Ridgeia symbiont genomes were assembled from trophosome metagenomes from worms collected from the Juan de Fuca Ridge (one and five individuals, respectively). We compared these assemblies to those of the sequenced Riftia and Tevnia symbionts. Pangenome composition, genome-wide comparisons of the nucleotide sequences, and pairwise comparisons of 2,313 orthologous genes indicated that “Ca. Endoriftia persephone” symbionts are structured on large geographical scales but also on smaller scales and possibly through host specificity. IMPORTANCE Remarkably, the intracellular symbionts of four to six species of eastern Pacific vent tubeworms all belong to the same phylotype of gammaproteobacteria, “Candidatus Endoriftia persephone.” Understanding the structure, dynamism, and interconnectivity of “Ca. Endoriftia persephone” populations is important to advancing our knowledge of the ecology and evolution of their host worms, which are often keystone species in vent communities. In this paper, we present the first genomes for symbionts associated with the species R. piscesae, from the Juan de Fuca Ridge. We then combine these genomes with published symbiont genomes from the East Pacific Rise tubeworms R. pachyptila and T

  12. Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods.

    PubMed

    Burbrink, Frank T; McKelvy, Alexander D; Pyron, R Alexander; Myers, Edward A

    2015-11-22

    Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities.

  13. Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods

    PubMed Central

    Burbrink, Frank T.; McKelvy, Alexander D.; Pyron, R. Alexander; Myers, Edward A.

    2015-01-01

    Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities. PMID:26609083

  14. Parallel and lineage-specific molecular adaptation to climate in boreal black spruce.

    PubMed

    Prunier, Julien; Gérardi, Sébastien; Laroche, Jérôme; Beaulieu, Jean; Bousquet, Jean

    2012-09-01

    In response to selective pressure, adaptation may follow different genetic pathways throughout the natural range of a species due to historical differentiation in standing genetic variation. Using 41 populations of black spruce (Picea mariana), the objectives of this study were to identify adaptive genetic polymorphisms related to temperature and precipitation variation across the transcontinental range of the species, and to evaluate the potential influence of historical events on their geographic distribution. Population structure was first inferred using 50 control nuclear markers. Then, 47 candidate gene SNPs identified in previous genome scans were tested for relationship with climatic factors using an F(ST) -based outlier method and regressions between allele frequencies and climatic variations. Two main intraspecific lineages related to glacial vicariance were detected at the transcontinental scale. Within-lineage analyses of allele frequencies allowed the identification of 23 candidate SNPs significantly related to precipitation and/or temperature variation, among which seven were common to both lineages, eight were specific to the eastern lineage and eight were specific to the western lineage. The implication of these candidate SNPs in adaptive processes was further supported by gene functional annotations. Multiple evidences indicated that the occurrence of lineage-specific adaptive SNPs was better explained by selection acting on historically differentiated gene pools rather than differential selection due to heterogeneity of interacting environmental factors and pleiotropic effects. Taken together, these findings suggest that standing genetic variation of potentially adaptive nature has been modified by historical events, hence affecting the outcome of recent selection and leading to different adaptive routes between intraspecific lineages.

  15. Significant role of structural fractures in Ren-Qiu buried-block oil field, eastern China

    SciTech Connect

    Fei, Q.; Xie-Pei, W.

    1983-03-01

    Ren-qui oil field is in a buried block of Sinian (upper Proterozoic) rocks located in the Ji-zhong depression of the western Bohai Bay basin in eastern China. The main reservoir consists of Sinian dolomite rocks. It is a fault block with a large growth fault on the west side which trends north-northeast with throws of up to 1 km (0.6 mi) or more. The source rocks for the oil are Paleogene age and overlie the Sinian dolomite rocks. The structural fractures are the main factor forming the reservoir of the buried-block oil field. Three structural lines, trending northeast, north-northeast, and northwest, form the regional netted fracture system. The north-northeast growth fault controlled the structural development of the buried block. The block was raised and eroded before the Tertiary sediments were deposited. In the Eocene Epoch, the Ji-zhong depression subsided, but the deposition, faulting, and related uplift of the block happened synchronously as the block was gradually submerged. At the same time, several horizontal and vertical karst zones were formed by the karst water along the netted structural fractures. The Eocene oil source rocks lapped onto the block and so the buried block, with many developed karst fractures, was surrounded by a great thickness of source rocks. As the growth fault developed, the height of the block was increased from 400 m (1300 ft) before the Oligocene to 1300 m (4250 ft) after. As the petroleum was generated, it migrated immediately into the karst fractures of the buried block along the growth fault. The karst-fractured block reservoir has an 800-m (2600-ft) high oil-bearing closure and good connections developed between the karst fractures.

  16. Seismic velocity structure and earthquake relocation for the magmatic system beneath Long Valley Caldera, eastern California

    NASA Astrophysics Data System (ADS)

    Lin, Guoqing

    2015-04-01

    A new three-dimensional (3-D) seismic velocity model and high-precision location catalog for earthquakes between 1984 and 2014 are presented for Long Valley Caldera and its adjacent fault zones in eastern California. The simul2000 tomography algorithm is applied to derive the 3-D Vp and Vp/Vs models using first-arrivals of 1004 composite earthquakes obtained from the original seismic data at the Northern California Earthquake Data Center. The resulting Vp model reflects geological structures and agrees with previous local tomographic studies. The simultaneously resolved Vp/Vs model is a major contribution of this study providing an important complement to the Vp model for the interpretation of structural heterogeneities and physical properties in the study area. The caldera is dominated by low Vp anomalies at shallow depths due to postcaldera fill. High Vp and low Vp/Vs values are resolved from the surface to ~ 3.4 km depth beneath the center of the caldera, corresponding to the structural uplift of the Resurgent Dome. An aseismic body with low Vp and high Vp/Vs anomalies at 4.2-6.2 km depth below the surface is consistent with the location of partial melt suggested by previous studies based on Vp models only and the inflation source locations based on geodetic modeling. The Sierran crystalline rocks outside the caldera are generally characterized with high Vp and low Vp/Vs values. The newly resolved velocity model improves absolute location accuracy for the seismicity in the study area and ultimately provides the basis for a high-precision earthquake catalog based on similar-event cluster analysis and waveform cross-correlation data. The fine-scale velocity structure and precise earthquake relocations are useful for investigating magma sources, seismicity and stress interaction and other seismological studies in Long Valley.

  17. Soft sediment deformation structures in the Lixian lacustrine sediments, eastern Tibetan Plateau and implications for postglacial seismic activity

    NASA Astrophysics Data System (ADS)

    Jiang, Hanchao; Zhong, Ning; Li, Yanhao; Xu, Hongyan; Yang, Huili; Peng, Xiaoping

    2016-10-01

    The eastern margin of the Tibetan Plateau is characterized by frequent earthquakes, which are closely associated with tectonic activity. To assess tectonic activity during the Late Pleistocene, we studied a well-exposed, 23-m-thick lacustrine sequence on the eastern margin of the plateau and found a variety of soft-sediment deformation (SSD) structures. Distributed in 24 stratigraphic levels, they comprise clastic dykes, ball-and-pillow structures, flame structures, clastic gravels, micro-faults, and slump folds. Most of the SSD structures indicate deformation mechanisms related to liquefaction and/or fluidization processes, most probably triggered by paleoseismic events. Given at least 4 historical earthquakes of M > 7 in the study area, most SSD structures in the Lixian lacustrine sequence indicate seismic events with M > 6 while simple flame structures point to some lower-magnitude earthquakes. OSL dating indicates that the sequence accumulated between 15.8 and 6.0 ka, giving a mean recurrence interval of 480 years for the 24 events, and demonstrating that lacustrine sediments in eastern Tibet have the potential to record a continuous seismic history on the centennial scale.

  18. Ancient trade routes shaped the genetic structure of horses in eastern Eurasia.

    PubMed

    Warmuth, Vera M; Campana, Michael G; Eriksson, Anders; Bower, Mim; Barker, Graeme; Manica, Andrea

    2013-11-01

    Animal exchange networks have been shown to play an important role in determining gene flow among domestic animal populations. The Silk Road is one of the oldest continuous exchange networks in human history, yet its effectiveness in facilitating animal exchange across large geographical distances and topographically challenging landscapes has never been explicitly studied. Horses are known to have been traded along the Silk Roads; however, extensive movement of horses in connection with other human activities may have obscured the genetic signature of the Silk Roads. To investigate the role of the Silk Roads in shaping the genetic structure of horses in eastern Eurasia, we analysed microsatellite genotyping data from 455 village horses sampled from 17 locations. Using least-cost path methods, we compared the performance of models containing the Silk Roads as corridors for gene flow with models containing single landscape features. We also determined whether the recent isolation of former Soviet Union countries from the rest of Eurasia has affected the genetic structure of our samples. The overall level of genetic differentiation was low, consistent with historically high levels of gene flow across the study region. The spatial genetic structure was characterized by a significant, albeit weak, pattern of isolation by distance across the continent with no evidence for the presence of distinct genetic clusters. Incorporating landscape features considerably improved the fit of the data; however, when we controlled for geographical distance, only the correlation between genetic differentiation and the Silk Roads remained significant, supporting the effectiveness of this ancient trade network in facilitating gene flow across large geographical distances in a topographically complex landscape.

  19. Habitat-independent spatial structure in populations of some forest birds in eastern North America.

    PubMed

    Ricklefs, Robert E

    2013-01-01

    The extent to which populations fill available ecological space is critical to evaluating niche-based theories of community assembly, but habitat suitability for populations is difficult to assess. The absence of a species from areas of otherwise suitable habitat might indicate localized species-specific influences, including biological interactions with competitors, consumers or pathogens, on local population persistence. I used Bray-Curtis ordination axis scores, based on the distributions of forest birds across census plots in eastern North America, as proxies of general features of habitat suitability to predict local abundances of each species of small land bird. I then applied spatial analysis to identify significant spatial structure (Moran's I) in residuals (positive or negative) from predicted local densities, which would indicate localized species-specific influences on population size. Fifty-eight of 79 species exhibited no significant spatial structure in residual abundances, indicating that the ordination axes reflect most of the spatial variation in environmental conditions and habitat characteristics that influence population distribution and density or that samples were too small to detect significant spatial variation. Twenty-one species exhibited significant habitat-independent spatial structure of residuals within distances of 100 km. Aggregations of residuals for these species were independently located, for the most part, and thus probably unrelated to general features of the environment that affect many species. Among factors considered as potential causes of spatial anomalies, positive density dependence (Allee effects), intraspecific social aggregation and area sensitivity in response to forest fragmentation find little support in this analysis. Because of the species-specific nature of these clustered residuals, specialized pathogens are potential candidates to drive spatial anomalies in host abundance.

  20. Main eddy vertical structures observed in the four major Eastern Boundary Upwelling Systems

    NASA Astrophysics Data System (ADS)

    Pegliasco, Cori; Chaigneau, Alexis; Morrow, Rosemary

    2015-09-01

    In the four major Eastern Boundary Upwelling Systems (EBUS), mesoscale eddies are known to modulate the biological productivity and transport near-coastal seawater properties toward the offshore ocean, however little is known about their main characteristics and vertical structure. This study combines 10 years of satellite-altimetry data and Argo float profiles of temperature and salinity, and our main goals are (i) to describe the main surface characteristics of long-lived eddies formed in each EBUS and their evolution, and (ii) to depict the main vertical structure of the eddy-types that coexist in these regions. A clustering analysis of the Argo profiles surfacing within the long-lived eddies of each EBUS allows us to determine the proportion of surface and subsurface-intensified eddies in each region, and to describe their vertical structure in terms of temperature, salinity and dynamic height anomalies. In the Peru-Chile Upwelling System, 55% of the sampled anticyclonic eddies (AEs) have subsurface-intensified maximum temperature and salinity anomalies below the seasonal pycnocline, whereas 88% of the cyclonic eddies (CEs) are surface-intensified. In the California Upwelling System, only 30% of the AEs are subsurface-intensified and all of the CEs show maximum anomalies above the pycnocline. In the Canary Upwelling System, ˜40% of the AEs and ˜60% of the CEs are subsurface-intensified with maximum anomalies extending down to 800 m depth. Finally, the Benguela Upwelling System tends to generate ˜40-50% of weak surface-intensified eddies and ˜50-60% of much stronger subsurface-intensified eddies with a clear geographical distribution. The mechanisms involved in the observed eddy vertical shapes are discussed.

  1. Contemporary genetic structure, phylogeography and past demographic processes of wild boar Sus scrofa population in Central and Eastern Europe.

    PubMed

    Kusza, Szilvia; Podgórski, Tomasz; Scandura, Massimo; Borowik, Tomasz; Jávor, András; Sidorovich, Vadim E; Bunevich, Aleksei N; Kolesnikov, Mikhail; Jędrzejewska, Bogumiła

    2014-01-01

    The wild boar (Sus scrofa) is one of the most widely distributed mammals in Europe. Its demography was affected by various events in the past and today populations are increasing throughout Europe. We examined genetic diversity, structure and population dynamics of wild boar in Central and Eastern Europe. MtDNA control region (664 bp) was sequenced in 254 wild boar from six countries (Poland, Hungary, Belarus, Ukraine, Moldova and the European part of Russia). We detected 16 haplotypes, all known from previous studies in Europe; 14 of them belonged to European 1 (E1) clade, including 13 haplotypes from E1-C and one from E1-A lineages. Two haplotypes belonged respectively to the East Asian and the Near Eastern clade. Both haplotypes were found in Russia and most probably originated from the documented translocations of wild boar. The studied populations showed moderate haplotype (0.714±0.023) and low nucleotide diversity (0.003±0.002). SAMOVA grouped the genetic structuring of Central and Eastern European wild boar into three subpopulations, comprising of: (1) north-eastern Belarus and the European part of Russia, (2) Poland, Ukraine, Moldova and most of Belarus, and (3) Hungary. The multimodal mismatch distribution, Fu's Fs index, Bayesian skyline plot and the high occurrence of shared haplotypes among populations did not suggest strong demographic fluctuations in wild boar numbers in the Holocene and pre-Holocene times. This study showed relatively weak genetic diversity and structure in Central and Eastern European wild boar populations and underlined gaps in our knowledge on the role of southern refugia and demographic processes shaping genetic diversity of wild boar in this part of Europe.

  2. The antifreeze potential of the spruce budworm thermal hysteresis protein.

    PubMed

    Tyshenko, M G; Doucet, D; Davies, P L; Walker, V K

    1997-09-01

    Antifreeze proteins (AFP) inhibit ice growth by surface adsorption that results in a depression of the freezing point below the melting point. The maximum level of this thermal hysteresis shown by the four structurally unrelated fish AFP is approximately 1.5 degrees C. In contrast, hemolymph and crude extracts from insects can have 5 degrees to 10 degrees C of thermal hysteresis. Based on the isolation, cloning, and expression of a thermal hysteresis protein (THP) from spruce budworm (Choristoneura fumiferana), the vastly greater activity is attributable to a 9 kDa protein. This novel, threonine- and cysteine-rich THP has striking effects on ice crystal morphology, both before and during freezing. It is also 10 to 30 times more active than any known fish AFP, offering the prospect of superior antifreeze properties in cryoprotective applications.

  3. Geology of the Plumtree area, Spruce Pine district, North Carolina

    USGS Publications Warehouse

    Brobst, Donald Albert

    1953-01-01

    This report describes the results of study and geologic mapping (1:12,000) in the 70-square-mile Plumtree area in the northeastern part of the Spruce Pine pegmatite district, on the Blue Ridge upland in western North Carolina. The district has been the chief domestic source of feldspar and sheet mica. The mining belt just west of the Blue Ridge Front trends northeast and is 25 miles long and 10 miles wide. The center of the Plumtree area lies 10 miles northeast of Spruce Pine pegmatite district, on the Blue Ridge upland in western North Carolina. The district has been the chief domestic source of feldspar and sheet mica. The mining belt just west of the Blue Ridge Front trends northeast and is 25 miles long and 10 miles wide. The center of the Plumtree area lies 10 miles northeast of Spruce Pine and includes parts of Mitchell and Avery Counties shown on the portions of the 7.5-minute Spruce Pine, Linville Falls, Newland, North Carolina, and Carvers Gap, North Carolina and Tennessee quadrangle. The topography varies from rugged mountains to rounded or flat topped hills near the entrenched, meandering master streams. Old erosion surfaces are approximately 600,1,100, 1,500, and 2,500 feet above the present master stream level. The area is in late youth or early maturity after rejuvenation.. The regionally metamorphosed rocks of the amophibolite facies form three mappable units: mica gneiss, mica schist, and hornblende rock. These rocks, perhaps of Precambrian age, are intimately interlayered with thicknesses of the individual layers ranging from less than one inch to several tons of feet. Field relationships and chemical data suggest that the mica (Carolina-type) rocks were derived from sandstones, graywackes, and shales and that the hornblende-rich (Roan-type) layers were derived from impure carbonate rocks. The igneous rocks include alaskite and associated pegmatite of early Paleozoic age (?), dunite and associated soapstone of a prepegmatite age, and a few diabasic

  4. Insect herbivory (Choristoneura fumiferana, Tortricidea) underlies tree population structure (Picea glauca, Pinaceae).

    PubMed

    Parent, Geneviève J; Giguère, Isabelle; Germanos, Gaby; Lamara, Mebarek; Bauce, Éric; MacKay, John J

    2017-02-16

    Variation in insect herbivory can lead to population structure in plant hosts as indicated by defence traits. In annual herbaceous, defence traits may vary between geographic areas but evidence of such patterns is lacking for long-lived species. This may result from the variety of selection pressures from herbivores, long distance gene flow, genome properties, and lack of research. We investigated the antagonistic interaction between white spruce (Picea glauca) and spruce budworm (SBW, Choristoneura fumiferana) the most devastating forest insect of eastern North America in common garden experiments. White spruces that are able to resist SBW attack were reported to accumulate the acetophenones piceol and pungenol constitutively in their foliage. We show that levels of these acetophenones and transcripts of the gene responsible for their release is highly heritable and that their accumulation is synchronized with the most devastating stage of SBW. Piceol and pungenol concentrations negatively correlate with rate of development in female SBW and follow a non-random geographic variation pattern that is partially explained by historical damage from SBW and temperature. Our results show that accumulation of acetophenones is an efficient resistance mechanism against SBW in white spruce and that insects can affect population structure of a long-lived plant.

  5. Insect herbivory (Choristoneura fumiferana, Tortricidea) underlies tree population structure (Picea glauca, Pinaceae)

    PubMed Central

    Parent, Geneviève J.; Giguère, Isabelle; Germanos, Gaby; Lamara, Mebarek; Bauce, Éric; MacKay, John J.

    2017-01-01

    Variation in insect herbivory can lead to population structure in plant hosts as indicated by defence traits. In annual herbaceous, defence traits may vary between geographic areas but evidence of such patterns is lacking for long-lived species. This may result from the variety of selection pressures from herbivores, long distance gene flow, genome properties, and lack of research. We investigated the antagonistic interaction between white spruce (Picea glauca) and spruce budworm (SBW, Choristoneura fumiferana) the most devastating forest insect of eastern North America in common garden experiments. White spruces that are able to resist SBW attack were reported to accumulate the acetophenones piceol and pungenol constitutively in their foliage. We show that levels of these acetophenones and transcripts of the gene responsible for their release is highly heritable and that their accumulation is synchronized with the most devastating stage of SBW. Piceol and pungenol concentrations negatively correlate with rate of development in female SBW and follow a non-random geographic variation pattern that is partially explained by historical damage from SBW and temperature. Our results show that accumulation of acetophenones is an efficient resistance mechanism against SBW in white spruce and that insects can affect population structure of a long-lived plant. PMID:28205578

  6. Influences of forest structure, climate and species composition on tree mortality across the eastern US.

    PubMed

    Lines, Emily R; Coomes, David A; Purves, Drew W

    2010-10-13

    Few studies have quantified regional variation in tree mortality, or explored whether species compositional changes or within-species variation are responsible for regional patterns, despite the fact that mortality has direct effects on the dynamics of woody biomass, species composition, stand structure, wood production and forest response to climate change. Using bayesian analysis of over 430,000 tree records from a large eastern US forest database we characterised tree mortality as a function of climate, soils, species and size (stem diameter). We found (1) mortality is U-shaped vs. stem diameter for all 21 species examined; (2) mortality is hump-shaped vs. plot basal area for most species; (3) geographical variation in mortality is substantial, and correlated with several environmental factors; and (4) individual species vary substantially from the combined average in the nature and magnitude of their mortality responses to environmental variation. Regional variation in mortality is therefore the product of variation in species composition combined with highly varied mortality-environment correlations within species. The results imply that variation in mortality is a crucial part of variation in the forest carbon cycle, such that including this variation in models of the global carbon cycle could significantly narrow uncertainty in climate change predictions.

  7. Adria-Europe crustal structure relationship in the Eastern Alps (project EASI)

    NASA Astrophysics Data System (ADS)

    Hetényi, György; Plomerová, Jaroslava; Bianchi, Irene; Kampfová Exnerová, Hana

    2016-04-01

    Project EASI is the first implemented Complementary Experiment within the AlpArray program (http://www.alparray.ethz.ch) and stands for Eastern Alpine Seismic Investigation. The seismological field experiment ran for one year, from Summer 2014 to Summer 2015, composed of 55 broadband stations deployed in zig-zag in a ca. 15 km-wide band along longitude 13.35°E, spanning 540 km from the Czech-German border to the Adriatic Sea. Here we present first results using P-to-S converted waves from teleseismic distances. The variation of Moho depth along the profile is analyzed and linked to the two colliding plates, Adria and Europe, as well as to the overlying lithospheric blocks of the Bohemian Massif. The suggested Moho "hole" between Adria and Europe is characterized. We investigate the anisotropic nature of the lower crust of both plates. We conclude on the structural relationship of Adria and Europe at the crustal level, and infer their respective positions at depth. Furthermore, preliminary S-to-P conversions illuminating the lithosphere-asthenosphere boundary test the significant depth variation of this boundary along the EASI transect and complement our receiver function study.

  8. Conductivity structure of the lithosphere-asthenosphere boundary beneath the eastern North American margin

    NASA Astrophysics Data System (ADS)

    Attias, Eric; Evans, Rob. L.; Naif, Samer; Elsenbeck, Jimmy; Key, Kerry

    2017-02-01

    Tectonic plate motion and mantle dynamics processes are heavily influenced by the characteristics of the lithosphere-asthenosphere boundary (LAB), yet this boundary remains enigmatic regarding its properties and geometry. The processes involved in rifting at passive margins result in substantial alteration of the lithosphere through the transition from continental to oceanic lithologies. Here we employ marine magnetotelluric (MT) data acquired along a ˜135 km long profile, offshore Martha's Vineyard, New England, USA, to image the electrical conductivity structure beneath the New England continental margin for the first time. We invert the data using two different MT 2-D inversion algorithms and present a series of models that are obtained using three different parameterizations: fully unconstrained, unconstrained with an imposed LAB discontinuity and a priori constrained lithosphere resistivity. This suite of models infers variability in the depth of the LAB, with an average depth of 115 km at the eastern North America passive margin. Models robustly detect a ˜350 Ωm lithospheric anomalous conductivity zone (LACZ) that extends vertically through the entire lithosphere. Our preferred conductivity model is consistent with regional P-to-S receiver function data, shear-wave velocity, gravity anomalies, and prominent geological features. We propose that the LACZ is indicative of paleolithospheric thinning, either resulting from kimberlite intrusions associated with rifting and the New England Great Meteor hot spot track, or from shear-driven localized deformation related to rifting.

  9. Detectability of temporal changes in fine structures near the inner core boundary beneath the eastern hemisphere

    NASA Astrophysics Data System (ADS)

    Yu, Wen-che

    2016-04-01

    The inner core boundary (ICB), where melting and solidification of the core occur, plays a crucial role in the dynamics of the Earth's interior. To probe temporal changes near the ICB beneath the eastern hemisphere, I analyze differential times of PKiKP (dt(PKiKP)), double differential times of PKiKP-PKPdf, and PKiKP coda waves from repeating earthquakes in the Southwest Pacific subduction zones. Most PKiKP differential times are within ±30 ms, comparable to inherent travel time uncertainties due to inter-event separations, and suggest no systematic changes as a function of calendar time. Double differential times measured between PKiKP codas and PKiKP main phases show promising temporal changes, with absolute values of time shifts of >50 ms for some observations. However, there are discrepancies among results from different seismographs in the same calendar time window. Negligible changes in PKiKP times, combined with changes in PKiKP coda wave times on 5 year timescales, favor a smooth inner core boundary with fine-scale structures present in the upper inner core. Differential times of PKiKP can be interpreted in the context of either melting based on translational convection, or growth based on thermochemical mantle-inner core coupling. Small dt(PKiKP) values with inherent uncertainties do not have sufficient resolution to distinguish the resultant longitudinal (melting) and latitudinal (growth) dependencies predicted on the basis of the two models on 5 year timescales.

  10. Another Look at the Eastern Banded Structure: A Stellar Debris Stream and a Possible Progenitor

    NASA Astrophysics Data System (ADS)

    Grillmair, C. J.

    2011-09-01

    Using the Sloan Digital Sky Survey Data Release 7, we re-examine the Eastern Banded Structure (EBS), a stellar debris stream first discovered in Data Release 5 and more recently detected in velocity space by Schlaufman et al. The visible portion of the stream is 18° long, lying roughly in the Galactic Anticenter direction and extending from Hydra to Cancer. At an estimated distance of 9.7 kpc, the stream is ≈170 pc across on the sky. The curvature of the stream implies a fairly eccentric box orbit that passes close to both the Galactic center and to the Sun, making it dynamically distinct from the nearby Monoceros, Anticenter, and GD-1 streams. Within the stream is a relatively strong, 2°-wide concentration of stars with a very similar color-magnitude distribution that we designate Hydra I. Given its prominence within the stream and its unusual morphology, we suggest that Hydra I is the last vestige of EBS's progenitor, possibly already unbound or in the final throes of tidal dissolution. Though both Hydra I and the EBS have a relatively high-velocity dispersion, given the comparatively narrow width of the stream and the high frequency of encounters with the bulge and massive constituents of the disk that such an eccentric orbit would entail, we suggest that the progenitor was likely a globular cluster and that both it and the stream have undergone significant heating over time.

  11. Geological structure of the deep eastern Mediterranean Sea (east of 25 Degrees E)

    SciTech Connect

    Montadert, L.; Sage, L.; Letouzey, J. )

    1988-08-01

    The deformation fronts of the Cyprus arc and the Mediterranean ridge, extending from the Turkey-Syria boundary to north Cyrenacia, are the southernmost superficial expression of the convergence between the Eurasian and African plates. They separate the Eastern Mediterranean deep basin into two different structural units: (1) A thrust belt, northward, with the presence of Cenozoic sedimentary basins which could be considered piggy-back basins (Iskenderun, Adana, Cilicia, and Antalya basins). These basins, filled by 4,000 to 6,000 m of Cenozoic sediments, lie on a substratum composed of south-vergent nappes emplaced between the Late Cretaceous and the late Miocene. (2) A foreland area, southward, where the thick Herodotus and Levantine sedimentary basins, relatively undeformed, lie on the passive and subsident African continental margin initiated during Late Triassic or early Liassic time. Due to the still-active collision between the thrust belt and the Erathosthenes seamount, Cyprus was uplifted and today represents the emerged part of the deformation front. During the Messinian, with the isolation of the Mediterranean Sea, evaporitic deposits including a salt layer (sometimes more than 2,000 m thick) were widely distributed into the Iskenderun, Cilicia, Antalya, Levantine, and Herodotus basins. In these basins, the Messinian sedimentation was directly controlled by basin topography.

  12. Thermocline Structure and ENSO Variability in the eastern equatorial Pacific during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Clark, S.; Koutavas, A.; Lynch-Stieglitz, J.; Rustic, G.

    2015-12-01

    The mean state and variability of the eastern equatorial Pacific (EEP) during the Last Glacial Maximum (LGM) are of great interest because of the region's role in the El Niño-Southern Oscillation (ENSO) and global climate. We investigated changes in thermocline structure between the Late Holocene (LH) and LGM with stable isotopes of planktonic foraminifera in sediment cores from the Galápagos. We measured δ18O in two species—Globigerinoides ruber, inhabiting the surface mixed layer, and Neogloboquadrina dutertrei, inhabiting the deep thermocline—in order to evaluate the vertical temperature contrast between the two species. We also measured δ18O of individual N. dutertrei from modern (late 20th century) and LGM sediments in order to assess thermocline temperature variability related to ENSO activity. Our data indicate a reduced vertical contrast in the upper ocean during the LGM, which is most consistent with a deeper thermocline and thicker mixed layer. Additionally, δ18O of individual N. dutertrei shells shows 2.5 times greater population variance in the LGM than in the modern sample. This large variance indicates that thermocline temperatures were more variable during the LGM than today, consistent with more active ENSO. Together, these results imply that the mean state of the EEP was characterized by a deeper thermocline and greater ENSO variability. The results further show the potential for reconstructing ENSO variability from deep-sea sediments of the EEP, where other geological archives of ENSO are currently extremely limited.

  13. SPRUCE Discovery Manual, 169 Investigations Indoors and Outdoors.

    ERIC Educational Resources Information Center

    Busch, Phyllis S.

    Contained are instructional materials developed by the Science Project Related to Upgrading Conservation Education ("SPRUCE"). It is designed for use with the SPRUCE "Discovery Box" and contains twenty-one sets of investigations based on the twenty-one packets of specimens in the box; three sets are recommended for each of…

  14. Invasive symbiont bearing (and other) foraminifera altering the community structure of eastern Mediterranean rocky reefs environments

    NASA Astrophysics Data System (ADS)

    Hyams-Kaphzan, Orit; Perelis Grossowicz, Lydia; Almogi-Labin, Ahuva

    2015-04-01

    The rocky reefs of the Israeli eastern Mediterranean shelf constitute a highly diverse marine ecosystem rich in macroalgae and calcareous organisms. The benthic foraminiferal community living in this ecosystem is rapidly changing due to massive invasion of symbiont bearing foraminifera (SBF) as well as other foraminiferal species of tropical origin. This trend facilitated by the ongoing increase in temperature enables more tropical species to adjust to the eastern Mediterranean habitats. In order to document the status of the benthic foraminiferal community structure rocky reefs at Akhziv (AK) and Carmel Head (CH), northern Israel were sampled by scuba diving. Different macroalgae species, including invasive ones, accommodating the live epiphytic benthic foraminifera were sampled twice a year at AK and in each season at CH in three depth intervals between 5-20 m, during 2013-4. The numerical abundance of the group ranges between 170-3500 #/10cc (wet macroalgae volume) without any significant difference in standing stocks within regions, water depths or macroalgae preference. In total 77 benthic foraminiferal species were identified 71 in CH and only 43 at AK. Species richness per site varied between 3 and 42 with higher values at CH. 25% of all species were aliens, mostly Lessepsian, that comprise on average 70% - 84% of the numerical abundance of AK and CH respectively. Cluster analysis using benthic foraminifera relative abundance data did not correlate with the different macroalgae species, water depths or seasonality, indicating that the foraminiferal community in the two regions is quite homogenous. Amphistegina lobifera a Lessepsian migrant is by far the most common species on the Israeli rocky reefs occurring in all samples and comprising 18-93% of the foraminiferal community. Heterostegina depressa behaves similarly to A. lobifera though it occurs in lower numbers. Pararotalia calcariformata, a recently arriving SBF occupies mainly shallow water sites at CH

  15. EFFECTS OF EASTERN REDCEDAR ON SMALL MAMMAL COMMUNITY STRUCTURE IN THE OKLAHOMA CROSSTIMBERS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianus), a native but invasive species in the Great Plains, has been associated with reduced herbaceous biomass in the canopy zone, altered plant species composition, and reduced understory light and soil water content. By ...

  16. Convection and Easterly Wave Structure Observed in the Eastern Pacific Warm-Pool during EPIC-2001

    NASA Technical Reports Server (NTRS)

    Peterson, Walter A.; Cifelli, R.; Boccippio, D.; Rutledge, S. A.; Fairall, C. W.; Arnold, James E. (Technical Monitor)

    2002-01-01

    During September-October 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC-2001) ITCZ field campaign focused on studies of deep convection in the warm-pool region of the East Pacific. In addition to the TAO mooring array, observational platforms deployed during the field phase included the NOAA ship RN Ronald H. Brown, the NSF ship RN Horizon, and the NOAA P-3 and NCAR C-130 aircraft. This study combines C-band Doppler radar, rawinsonde, and surface heat flux data collected aboard the RN Brown to describe ITCZ convective structure and rainfall statistics in the eastern Pacific as a function of 3-5 day easterly wave phase. Three distinct easterly wave passages occurred during EPIC-2001. Wind and thermodynamic data reveal that the wave trough axes exhibited positively correlated U and V winds and a slight westward phase tilt with height. A relatively strong (weak) northeasterly deep tropospheric shear followed the trough (ridge) axis. Temperature and humidity perturbations exhibited mid-to upper level cooling (warming) and drying (moistening) in the northerly (trough and southerly) phase. At low levels warming (cooling) occurred in the northerly (southerly) phase with little change in the relative humidity, though mixed layer mixing ratios were larger during the northerly phase. When composited, radar, sounding, lightning and surface heat flux observations suggest the following systematic behavior as a function of wave phase: approximately zero to one quarter wavelength ahead of (behind) the wave trough in northerly (southerly) flow, larger (smaller) CAPE, lower (higher) CIN, weaker (stronger) tropospheric shear, higher (lower) conditional mean rain rates, higher (lower) lightning flash densities, and more (less) robust convective vertical structure occurred. Latent and sensible heat fluxes reached a minimum in the northerly phase and then increased through the trough, reaching a peak during the ridge phase

  17. Three-dimensional structural evolution and kinematics of the Piedemonte Llanero, Central Llanos foothills, Eastern Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Egbue, Obi; Kellogg, James

    2012-11-01

    The Piedemonte Llanero is a wedge duplex zone in the Llanos foothills on the eastern flank of the Eastern Cordillera of Colombia. It is located northeast of the Cusiana and Cupiagua hydrocarbon fields. The area is characterized by a series of moderate to high-angle duplexes with east-southeast verging thin-skinned and thick-skinned tectonics. We present a structural model constrained by 2-D and 3-D seismic reflection data, surface geology, and well data. The structural analysis is based on backward modeling (kinematic restoration) and forward modeling using transfer-flexural slip and fault slip fold algorithms. The structures are significantly tighter in the northern segment compared to the southern segment of the overthrust trend. We estimate approximately 17 km of shortening in the northern duplex zone, and about 26 km total shortening for the southern duplex zone. We propose that thin-skinned in-sequence imbricate thrust stack deformation produced most of the shortening. The main Andean deformation (80% of the total shortening) commenced in the Piedemonte area about 6 Ma with rapid shortening and uplift in the area resulting in the development of an active-roof duplex structure as the cover was bulldozed forward by a horse block (Monterralo anticline) ramping up to a detachment at the base of C2, then ramping to the surface as the Yopal thrust. Later the horse blocks in the wedge rose, underthrusting the cover in a passive-roof duplex triangle zone. This was followed by an out-of-sequence Laramide-style thick-skinned basement-uplift of the range which produced much of the structural relief of the Eastern Cordillera. Cenozoic deformation in the Eastern Cordillera has been primarily range-normal, but has involved an increasing component of mountain-parallel right-lateral shear in the last 2 Ma.

  18. Population genetic structure of two columnar cacti with a patchy distribution in eastern Brazil.

    PubMed

    Moraes, Evandro M; Abreu, Aluana G; Andrade, Sónia C S; Sene, Fabio M; Solferini, Vera N

    2005-11-01

    The genetic variability and population genetic structure of six populations of Praecereus euchlorus and Pilosocereus machrisii were investigated. The genetic variability in single populations of Pilosocereus vilaboensis, Pilosocereus aureispinus, and Facheiroa squamosa was also examined. All of these cacti species have a patchy geographic distribution in which they are restricted to small areas of xeric habitats in eastern Brazil. An analysis of genetic structure was used to gain insights into the historical mechanisms responsible for the patchy distribution of P. euchlorus and P. machrisii. High genetic variability was found at the populational level in all species (P=58.9-92.8%, A(p)=2.34-3.33, H(e)=0.266-0.401), and did not support our expectations of low variability based on the small population size. Substantial inbreeding was detected within populations (F(IS)=0.370-0.623). In agreement with their insular distribution patterns, P. euchlorus and P. machrisii had a high genetic differentiation (F(ST)=0.484 and F(ST)=0.281, respectively), with no evidence of isolation by distance. Accordingly, estimates of gene flow (N(m)) calculated from F(ST) and private alleles were below the level of N(m)=1 in P. machrisii and P. euchlorus. These results favored historical fragmentation as the mechanism responsible for the patchy distribution of these two species. The genetic distance between P. machrisii and P. vilaboensis was not compatible with their taxonomic distinction, indicating a possible local speciation event in this genus, or the occurrence of introgression events.

  19. Paleogene strata of the Eastern Los Angeles basin, California: Paleogeography and constraints on neogene structural evolution

    USGS Publications Warehouse

    McCulloh, T.H.; Beyer, L.A.; Enrico, R.J.

    2000-01-01

    Post-Paleogene dextral slip of 8-9 km is demonstrated for the southeastern part of the Whittier fault zone in the eastern Los Angeles basin area of southern California. A linear axis of greatest thickness for the combined upper Paleocene and lower to lower-middle Eocene clastic formations intersects the fault zone and is offset by it to give the new measure. Fragmentary evidence hints that the Whittier structural zone may have exerted control on bathymetric-topographic relief and sedimentation even in latest Paleocene (ca. 54 Ma). A clear topographic influence was exerted by 20-17 Ma. Strike-slip and present deformational style is younger than ca. 8 Ma. Our Paleogene isopach map extends as far west as long 117??58'W and is a foundation for companion zonal maps of predominant lithology and depositional environments. Integration of new palynological data with published biostratigraphic results and both new and published lithologic and sedimentological interpretations support the zonal maps. Reconstruction of marine-nonmarine facies and fragmented basin margins yields a model for the northeastern corner of a Paleogene coastal basin. Palinspastic adjustment for the Neogene-Quaternary Whittier fault offset and a reasoned westerly extension of the northern edge of the basin model yield a reconstruction of Paleogene paleogeography-paleoceanography. Our reconstruction is based partly on the absence of both Paleocene and Eocene deposits beneath the unconformable base of the middle Miocene Topanga Group in a region nowhere less than 15 km wide between the Raymond-Sierra Madre-Cucamonga fault zone and the northern edge of the Paleocene basin. Thus, Paleogene strata of the Santa Monica Mountains could not have been offset from the northern extension of the Santa Ana Mountains by sinistral slip on those boundary faults. Structural rearrangements needed to accommodate the clockwise rotation of the western Transverse Ranges from the early Miocene starting position are thereby

  20. The vertical structure of the eastern Pacific ITCZs and associated circulation using the TRMM Precipitation Radar and in situ data

    NASA Astrophysics Data System (ADS)

    Huaman, L.; Takahashi, K.

    2016-08-01

    The atmospheric circulation associated with the eastern Pacific single and double ITCZs, particularly its vertical structure, is little known due to the sparce observations. Using precipitation profiles from the Tropical Rainfall Measure Mission (TRMM) Precipitation Radar, with approximations to the liquid water and energy budget equations, we estimated vertical profiles of latent heating and vertical velocity in the far eastern Pacific (95°W-85°W) ITCZs in the 800-730 hPa layer. We combined this with Eastern Pacific Investigation of Climate campaign (EPIC2001) and other in situ data to produce a preliminary characterization of the meridional-vertical circulation. We found evidence of a double-cell structure in boreal fall between the ITCZ and the equator, with both shallow and upper level peaks in vertical velocity. In spring, the flow poleward of the two ITCZs has a single-cell structure, although around the equator it shows some hints of the double cells. Reanalysis and satellite-based data are shown to be unreliable for describing the vertical structure of the circulation.

  1. The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

    NASA Astrophysics Data System (ADS)

    Mulibo, Gabriel D.; Nyblade, Andrew A.

    2013-08-01

    P and S relative arrival time residuals from teleseismic earthquakes recorded on over 60 temporary AfricaArray broadband seismic stations deployed in Uganda, Tanzania, and Zambia between 2007 and 2011 have been inverted, together with relative arrival time residuals from earthquakes recorded by previous deployments, for a tomographic image of mantle wave speed variations extending to a depth of 1200 km beneath eastern Africa. The image shows a low-wave speed anomaly (LWA) well developed at shallow depths (100-200 km) beneath the Eastern and Western branches of the Cenozoic East African rift system and northwestern Zambia, and a fast wave speed anomaly at depths ≤ 350 km beneath the central and northern parts of the East African Plateau and the eastern and central parts of Zambia. At depths ≥350 km the LWA is most prominent under the central and southern parts of the East African Plateau and dips to the southwest beneath northern Zambia, extending to a depth of at least 900 km. The amplitude of the LWA is consistent with a ˜150-300 K thermal perturbation, and its depth extent indicates that the African superplume, originally identified as a lower mantle anomaly, is likely a whole mantle structure. A superplume extending from the core-mantle boundary to the surface implies an origin for the Cenozoic extension, volcanism, and plateau uplift in eastern Africa rooted in the dynamics of the lower mantle.

  2. Space-time structure of the 2003 geomagnetic jerk at Mid-Eastern Asia

    NASA Astrophysics Data System (ADS)

    Ou, Jiaming; Du, Aimin; Xu, Wenyao; Yang, Dongmei

    2015-04-01

    The 2003 jerk has an abrupt change in the geomagnetic secular variation (SV), and was recognized as a local phenomenon of internal origin from the satellite observations (Olsen and Mandea, 2007). Notable strength of the 2003 jerk is located at Mid-Eastern Asia. The temporal and spatial features at this area are important to resolve the Earth's core fluid flow dynamics at local scale (e.g. Wardinski et al., 2008). We investigate the temporal-spatial development of the 2003 jerk in more detail at Mid-Eastern Asia with the ground-based observations and CHAOS-3 core field model. We select the data in the international geomagnetic quiet days to calculate the monthly means. In order to reduce the influence of the external field, we adopt a function comprising the terms associated with the indices of the geomagnetic activity, and the terms of the periodic signals on the observatory monthly means data (Stewart and Whaler, 1992). We then use an empirical AR-2 model to represent the internal field signals in the observatory data. The extreme detection is applied to identify the jerk in the SV time series. The onset time and the strength of the 2003 jerk are obtained through the detection for geomagnetic field component, X, Y and Z. The maximum of the strength of the 2003 jerk is located under the Indian mainland. The onset time of this jerk propagates approximately southeastward. Two jerks in 2001 and 2003 for the Z component are further compared and they are confirmed as independent processes. We suggest the jerk in 2001 identical to the well known 1999 jerk in Europe (Mandea et al., 2000). Our results reveal the fine structures of the 2003 jerk that corroborate the conclusions in previous studies. The larger scale time-spatial structure given by the AR-2 model constructed from ground observatory data (monthly values) is consistent with the results from the CHAOS-3 model. This structure can be applied for further inversion of the local core surface fluid flow motions

  3. Analyses of Great Smoky Mountain red spruce tree-ring data. Forest Service general technical report

    SciTech Connect

    Van Deusen, P.C.

    1988-05-01

    Contents include: Southern Appalachian Red Spruce--Fraser Fir Forests; A tree ring analysis of Red Spruce in the Southern Appalachian Mountains; Utilizing time series models and spatial analysis of forecast residuals for tree-ring analysis of Red Spruce; A fractal approach to analysis of tree-ring increments; Red Spruce Tree Ring Analysis using a Kalman Filter.

  4. Basement structural control on Cretaceous pull-apart basins of the central Eastern Egypt Desert

    NASA Astrophysics Data System (ADS)

    McCaffrey, K.; El Kazzaz, Y.; Holdsworth, B.

    2006-12-01

    The present-day Red Sea / Gulf of Suez rift system is attributed to extensional block faulting with along-axis segmentation into sub-basins with different dip polarities. The northwestern margin of the Red Sea - Gulf of Suez rift system is exposed for about 400 km along the northwestern Red Sea coast near Quseir to the tip of the Gulf of Suez at Suez City. This area contains elements of the pre-Red Sea structural pattern which has been viewed in similar terms as one of fault-related basin formation. Four distinct depocenters (sub-basins) separated by complex accommodation zones are present containing 500-700m thick section ranging in age from the Late Cretaceous to the Middle Eocene. Each sub-basin is asymmetric, bounded on one side by a major NW-trending border fault system with large throws (3-6 km in general) with a dominant strata dip direction toward the border fault system. These basins are arranged in en echelon patterns and now form separate elongated ridges surrounded by basement rocks. Our study of the tectonic evolution of the central eastern section of the Gulf of Suez rift and the Northwestern Red Sea has focused on the interaction of pre-existing basement fabrics with the pre-Red Sea structural development. The study involved analysis of LandsatTM images and aerial photographs integrated with results from reconnaissance geological mapping. Our provisional results indicate that the Gebel Um Hammad/Duwi and Hammadat sub-basins were sited in pull-apart structures created by dextral reactivation of E-W to ENE-WSW trending basement fault zones. We show how the basin-bounding fault systems, lower order normal faults and folds in both hangingwall sequences and in basement are compatible with a Late Cretaceous to Early Eocene strike-slip regime. In contrast, the main Red Sea Gulf of Suez rift shows no evidence for strike-slip influence with the main boundary faults cutting across basement fabrics, however, as pointed out by previous authors, rift segmentation

  5. [Richard Spruce, botanist-South America's explorer].

    PubMed

    Seaward, M R

    2000-01-01

    Between 1849 and 1864, the English botanist and explorer Richard Spruce carried out a detailed study of the Amazon flora and the costumes of the peoples who inhabited the region. To date a large part of the existing knowledge about several botanical families in the region stems from this scientist's efforts. His comprehensive interests, his detailed and precise descriptions were outstanding: nothing seems to have been left out of his scrutiny and recording aptitude. Not only was Spruce a remarkable botanist but he was also a distinctive anthropologist, linguist (he knew French, Spanish and Portuguese), geologist and geographer, as well as an acute sociological observer of the political systems and habits of the Amazonian and Andean trips in which has has been. He could thus make a considerable contribution to the understanding of indigenous beliefs and practices, as well as to the knowledge and uses of plants within the Amazonian context. Also important was his participation in the economic exploration of local species, particularly as regards the Hevea and the Cinchona genera.

  6. Orogenic structure of the Eastern Alps, Europe, from TRANSALP deep seismic reflection profiling

    NASA Astrophysics Data System (ADS)

    Lüschen, Ewald; Lammerer, Bernd; Gebrande, Helmut; Millahn, Karl; Nicolich, Rinaldo; Transalp Working Group

    2004-09-01

    The TRANSALP Group, comprising of partner institutions from Italy, Austria and Germany, acquired data on a 340 km long deep seismic reflection line crossing the Eastern Alps between Munich and Venice. Although the field work was split into four campaigns, between fall 1998 and summer 2001, the project gathered for the first time a continuous profile across the Alps using consistent field acquisition and data processing parameters. These sections span the orogen itself, at its broadest width, as well as the editor Fred Davey and the two adjacent basins. Vibroseis and explosion data, complementary in their depth penetration and resolution characteristics, were obtained along with wide-angle and teleseismic data. The profile shows a bi-vergent asymmetric structure of the crust beneath the Alpine axis which reaches a maximum thickness of 55 km, and 80-100 km long transcrustal ramps, the southward dipping 'Sub-Tauern-Ramp' and the northward-dipping 'Sub-Dolomites-Ramp'. Strongly reflective patterns of these ramps can be traced towards the north to the Inn Valley and towards the south to the Valsugana thrust belt, both of which show enhanced seismicity in the brittle upper crust. The seismic sections do not reveal any direct evidence for the presence of the Periadriatic Fault system, the presumed equivalent to the Insubric Line in the Western Alps. According to our new evolutionary model, the Sub-Tauern-Ramp is linked at depth with remnants of the subducted Penninic Ocean. The 'crocodile'-type model describes an upper/lower crustal decoupling and wedging of both the European and the Adriatic-African continents.

  7. Eastern Barents Sea: crustal structure of the craton-shelf transition.

    NASA Astrophysics Data System (ADS)

    Shulgin, Alexey; Mjelde, Rolf

    2015-04-01

    The former disputed area of the Barents Sea is a hot area for geophysical investigations, since little is known so far about its deep crustal structure, while the area is of a particular interest for hydrocarbon prospecting. Once the territorial disputes have been finally settled recently, a regional ocean bottom seismometer (OBS) survey was conducted in this area in summer 2012. The seismic line is a northeast-southwest trending profile located in the easternmost area of the Norwegian waters. The transect is approximately 600 km long and includes marine and onshore parts. The major part of the profile was recorded on the 38 OBS with an average spacing of 13 km. In addition, 80 land stations (with 1 km spacing) were deployed during the field campaign: 50 of them on the southern continuation of the marine profile, and 30 were deployed semi-parallel to the marine profile along the eastern coast of the Varanger Peninsula. We present the crustal model of the craton-shelf transition obtained from the seismic tomography and gravity modeling. The model shows the presence of six principally different crustal domains, which correlate with the near-surface observations. The interpretation of these changes along the profile links to the different tectonic settings along the profile. Presence of the large volumes of the underplated material is attributed to the rifting events on the shelf. The lateral variations in the seismic velocities in the onshore part of the transect is interpreted as a change from the typical cratonic crust to the continental type crust of the Varanger terrane. We also show the results of the ongoing work on the S-waves tomography modeling for the same profile. The combined interpretation of P and S data will provide additional details on the compositional differences between crustal domains and will give extra information on the origin of the underplating.

  8. Seismic velocity structure and seismotectonics of the eastern San Francisco Bay region, California

    USGS Publications Warehouse

    Hardebeck, J.L.; Michael, A.J.; Brocher, T.M.

    2007-01-01

    The Hayward Fault System is considered the most likely fault system in the San Francisco Bay Area, California, to produce a major earthquake in the next 30 years. To better understand this fault system, we use microseismicity to study its structure and kinematics. We present a new 3D seismic-velocity model for the eastern San Francisco Bay region, using microseismicity and controlled sources, which reveals a ???10% velocity contrast across the Hayward fault in the upper 10 km, with higher velocity in the Franciscan Complex to the west relative to the Great Valley Sequence to the east. This contrast is imaged more sharply in our localized model than in previous regional-scale models. Thick Cenozoic sedimentary basins, such as the Livermore basin, which may experience particularly strong shaking during an earthquake, are imaged in the model. The accurate earthquake locations and focal mechanisms obtained by using the 3D model allow us to study fault complexity and its implications for seismic hazard. The relocated hypocenters along the Hayward Fault in general are consistent with a near-vertical or steeply east-dipping fault zone. The southern Hayward fault merges smoothly with the Calaveras fault at depth, suggesting that large earthquakes may rupture across both faults. The use of the 3D velocity model reveals that most earthquakes along the Hayward fault have near-vertical strike-slip focal mechanisms, consistent with the large-scale orientation and sense of slip of the fault, with no evidence for zones of complex fracturing acting as barriers to earthquake rupture.

  9. Study of Reservoir Heterogencities and Structural Features Affecting Production in the Shallow Oil Zone, Eastern Elk Hills Area, California

    SciTech Connect

    Janice Gillespie

    2004-11-01

    Late Neogene (Plio-Pleistocene) shallow marine strata of the western Bakersfield Arch and Elk Hills produce hydrocarbons from several different reservoirs. This project focuses on the shallow marine deposits of the Gusher and Calitroleum reservoirs in the Lower Shallow Oil Zone (LSOZ). In the eastern part of the study area on the Bakersfield Arch at North and South Coles Levee field and in two wells in easternmost Elk Hills, the LSOZ reservoirs produce dry (predominantly methane) gas. In structurally higher locations in western Elk Hills, the LSOZ produces oil and associated gas. Gas analyses show that gas from the eastern LSOZ is bacterial and formed in place in the reservoirs, whereas gas associated with oil in the western part of the study area is thermogenic and migrated into the sands from deeper in the basin. Regional mapping shows that the gas-bearing LSOZ sands in the Coles Levee and easternmost Elk Hills area are sourced from the Sierra Nevada to the east whereas the oil-bearing sands in western Elk Hills appear to be sourced from the west. The eastern Elk Hills area occupied the basin depocenter, farthest from either source area. As a result, it collected mainly low-permeability offshore shale deposits. This sand-poor depocenter provides an effective barrier to the updip migration of gases from east to west. The role of small, listric normal faults as migration barriers is more ambiguous. Because our gas analyses show that the gas in the eastern LSOZ reservoirs is bacterial, it likely formed in-place near the reservoirs and did not have to migrate far. Therefore, the gas could have been generated after faulting and accumulated within the fault blocks as localized pools. However, bacterial gas is present in both the eastern AND western parts of Elk Hills in the Dry Gas Zone (DGZ) near the top of the stratigraphic section even though the measured fault displacement is greatest in this zone. Bacterial gas is not present in the west in the deeper LSOZ which

  10. Deep resistivity structure along the Longmen Mountain fault zone in the eastern Tibetan plateau of China

    NASA Astrophysics Data System (ADS)

    Wang, X.; Zhang, G.; Luo, W.; Luo, H.; Cai, X.; Zhou, Y.; Zhang, W.; Qin, Q.

    2012-12-01

    1.Introduction Many researchers (e.g.,Wang et al.,2009) have proposed the relevant knowledge of tectonic evolution and dynamic characteristics of the Longmen Mountain belt as well as the Songpan-Ganzi and Yangtze blocks in the past few decades, the knowledge of shallow thrust nappe tectonic along the belt has then been generally recognized. It's, however, still difficult to image the deep crust and mantle structures and reveal the dynamic mechanism of the crustal formation under the Longmen Mountain. In this study, we carried out the MT experiments along and across the Longmen mountain region and investigated the relationships between the crust structure and seismic activity basing on the latest MT geological results. 2. Field observations We conducted three MT experiment profiles in the eastern Tibetan Plateau. One is along the Mingshan-Guangyuan profile parallel with the structural direction, and another two profiles (Maqu-Gaoliangzhen and Luqu-Hechuan) perpendicular to the Longmen Mountain fault zone. In this study, we use the conventional magnetotelluric (MT) data combine with the long-period magnetotelluric (LMT) data to observe electromagnetic response. The MT and LMT data was observed by using the V8 instrument and LEMI-417, respectively. 3. Conclusion (1) According to the results of MT inversion, we find that the high concentration of stress process along the Songpan-Ganzi block and the Yangtze block colliding zone might result from the deep crust-mantle tough shear Zone of Longmen Mountain expanded to mid-upper crust, and finally leads to a new rupture. This could be one of the focal mechanisms of the Wenchuan earthquake (Ms 8.0) generating. The deep resistivity structure along the Longmen Mountain fault zone can be divided into southern,middle and northern segments from southwest to northeast. The total resistivity of southern segment is lower than the middle and northern portions. We suggest that the upper crust of the Longmen Mountain, south of Dayi

  11. Constrain the crust and upper mantle structure beneath the equatorial Eastern Pacific Rise from ambient noise and earthquake surface waves

    NASA Astrophysics Data System (ADS)

    Gao, C.; Yao, H.; Gouedard, P.; Collins, J. A.; McGuire, J. J.; van der Hilst, R.

    2012-12-01

    In this study we combine ambient noise and earthquake surface waves to jointly constrain the crust and upper mantle shear velocity structure beneath the equatorial eastern Pacific Rise using data from ocean bottom seismometers deployed in 2008. We measure the inter-station Rayleigh-wave phase velocity dispersion curves of the fundamental mode in the period band 2 - 30 s and the first higher mode in the period band 3 - 7 s from vertical component ambient noise cross-correlation functions. We also determine the inter-station phase velocity dispersion curves in the period band 20 - 100 s from an earthquake-based surface-wave two-station method. The average dispersion data from both ambient noise and earthquake surface waves are used to determine the average shear velocity structure in the crust and upper mantle using a global searching Neighborhood algorithm. Our results reveal a pronounced low velocity zone in the upper mantle with the shear wave speed as slow as 3.85 km/s beneath the equatorial eastern Pacific Rise, possibly caused by a combination of high temperature and the presence of partial melt beneath the mid-ocean ridges. We will also measure Love wave dispersion curves from transverse component ambient noise cross-correlation functions and earthquake surface waves. Together with Rayleigh-wave dispersion measurements, we will determine the radial anisotropy to constrain the deformation of the crust and upper mantle beneath the equatorial eastern Pacific Rise.

  12. Upper Mantle Discontinuity Structure Beneath the Western Atlantic Ocean and Eastern North America from SS Precursors

    NASA Astrophysics Data System (ADS)

    Schmerr, N. C.; Beghein, C.; Kostic, D.; Baldridge, A. M.; West, J. D.; Nittler, L. R.; Bull, A. L.; Montesi, L.; Byrne, P. K.; Hummer, D. R.; Plescia, J. B.; Elkins-Tanton, L. T.; Lekic, V.; Schmidt, B. E.; Elkins, L. J.; Cooper, C. M.; ten Kate, I. L.; Van Hinsbergen, D. J. J.; Parai, R.; Glass, J. B.; Ni, J.; Fuji, N.; McCubbin, F. M.; Michalski, J. R.; Zhao, C.; Arevalo, R. D., Jr.; Koelemeijer, P.; Courtier, A. M.; Dalton, H.; Waszek, L.; Bahamonde, J.; Schmerr, B.; Gilpin, N.; Rosenshein, E.; Mach, K.; Ostrach, L. R.; Caracas, R.; Craddock, R. A.; Moore-Driskell, M. M.; Du Frane, W. L.; Kellogg, L. H.

    2015-12-01

    Seismic discontinuities within the mantle arise from a wide range of mechanisms, including changes in mineralogy, major element composition, melt content, volatile abundance, anisotropy, or a combination of the above. In particular, the depth and sharpness of upper mantle discontinuities at 410 and 660 km depth are attributed to solid-state phase changes sensitive to both mantle temperature and composition, where regions of thermal heterogeneity produce topography and chemical heterogeneity changes the impedance contrast across the discontinuity. Seismic mapping of this topography and sharpness thus provides constraint on the thermal and compositional state of the mantle. The EarthScope USArray is providing unprecedented access to a wide variety of new regions previously undersampled by the SS precursors. This includes the boundary between the oceanic plate in the western Atlantic Ocean and continental margin of eastern North America. Here we use a seismic array approach to image the depth, sharpness, and topography of the upper mantle discontinuities, as well as other possible upper mantle reflectors beneath this region. This array approach utilizes seismic waves that reflect off the underside of a mantle discontinuity and arrive several hundred seconds prior to the SS seismic phase as precursory energy. In this study, we collected high-quality broadband data SS precursors data from shallow focus (< 30 km deep), mid-Atlantic ridge earthquakes recorded by USArray seismometers in Alaska. We generated 4th root vespagrams to enhance the SS precursors and determine how they sample the mantle. Our data show detection of localized structure on the discontinuity boundaries as well as additional horizons, such as the X-discontinuity and a potential reflection from a discontinuity near the depth of the lithosphere-asthenosphere boundary. These structures are related to the transition from predominantly old ocean lithosphere to underlying continental lithosphere, as while

  13. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps.

    PubMed

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-11-26

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E-W to WNW-ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE-SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P-T estimates yield high strain rates of 10(- 11) to 10(- 13) s(- 1), depending on the temperature (400-350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376-328 °C, and 306-132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial deformation

  14. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps☆

    PubMed Central

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-01-01

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E–W to WNW–ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE–SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P–T estimates yield high strain rates of 10− 11 to 10− 13 s− 1, depending on the temperature (400–350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376–328 °C, and 306–132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial

  15. Status of the spruce; Fir cooperative research program

    SciTech Connect

    Hertel, G.D.; Zarnoch, S.J.; Arre, T. ); Eager, C. ); Mohnen, V. ); MedLarz, S. )

    1987-01-01

    Aside from the mixed conifer forest in the San Bernadino National Forest near the Los Angeles Basin, the only significant visible decline and mortality of a U.S. forest possibly caused by regional air pollution is found in the high elevation spruce/fir forests of the Appalachians (VA, NC, TN, W VA), Adirondacks (NY), Green Mountains (VT), and the White Mountains (NH). In January, most of the scientists that have or are currently studying Spruce-Fir conditions met in Philadelphia. They came to a consensus on the regional condition of the Spruce-Fir forests. The results of that meeting are summarized.

  16. Gravity field and structure of the Sorong Fault Zone, eastern Indonesia

    NASA Astrophysics Data System (ADS)

    Sardjono

    Gravity surveys along coastlines of islands in the region Banggai-Sula, Eastern Sulawesi, Halmahera, Bacan and Obi were carried out as part of the Sorong Fault Zone Project. Results of the Surveys were integrated with gravity data previously acquired by other projects, including on-land gravity data from the Bird Head area Irian Jaya (Dow et al 1986), Seram Island (Milsom 1977), Buru Island (Oemar and Reminton 1993) and Central Sulawesi (Silver et al. 1983) as well as marine gravity information within and surrounding the Sorong Fault Zone (Bowin et al. 1980). Gravity expeditions of the Sorong Fault Zone Project also include measurements in Mayu Island and the island group of Talaud, situated further north in the Central Molucca Sea region. A total of one hundred and forty two gravity data were acquired in the region of Banggai-Sula islands, forty seven in eastern part of Central Sulawesi, about four hundred in Halmahera, Bacan and Obi, and seventy nine in Mayu and Talaud. Surveys in the eastern part of Central Sulawesi were carried out for the purpose of tieing the older gravity data obtained from Silver et al. (1983) and the more recent data of the Sorong Fault Zone Project. About one thousand thirty hundred and thirty gravity data were acquired as part of the Irian Jaya Geological Mapping Project (IJGMP) in the period of 1978-1983, a project commissioned by the Indonesian Geological Research and Development Centre (GRDC) and the Australian Bureau of Mineral Resources (BMR). The remoteness of the survey areas of the Sorong Fault Zone Project necessitated a careful planning for travel arrangements and provision of logistics. A wide range of magnitude of gravity field was observed in the Sorong Fault Zone, extending from values below -250 mGal recorded in the southern part of the Molucca Sea to values in excess of +320 mGal measured near to sea level in the coastal areas south of Mangole and north of Sulabesi, the two islands of the Sula Group. Steep gradients of

  17. A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce.

    PubMed

    Hammerbacher, Almuth; Schmidt, Axel; Wadke, Namita; Wright, Louwrance P; Schneider, Bernd; Bohlmann, Joerg; Brand, Willi A; Fenning, Trevor M; Gershenzon, Jonathan; Paetz, Christian

    2013-07-01

    Norway spruce (Picea abies) forests suffer periodic fatal attacks by the bark beetle Ips typographus and its fungal associate, Ceratocystis polonica. Norway spruce protects itself against fungal and bark beetle invasion by the production of terpenoid resins, but it is unclear whether resins or other defenses are effective against the fungus. We investigated stilbenes, a group of phenolic compounds found in Norway spruce bark with a diaryl-ethene skeleton with known antifungal properties. During C. polonica infection, stilbene biosynthesis was up-regulated, as evidenced by elevated transcript levels of stilbene synthase genes. However, stilbene concentrations actually declined during infection, and this was due to fungal metabolism. C. polonica converted stilbenes to ring-opened, deglycosylated, and dimeric products. Chromatographic separation of C. polonica protein extracts confirmed that these metabolites arose from specific fungal enzyme activities. Comparison of C. polonica strains showed that rapid conversion of host phenolics is associated with higher virulence. C. polonica is so well adapted to its host's chemical defenses that it is even able to use host phenolic compounds as its sole carbon source.

  18. Rift Structure along the Eastern Continental Margin of India - new constraints on style of breakup of the Indian landmass from the eastern Gondwanaland

    NASA Astrophysics Data System (ADS)

    Ismaiel, M.; Krishna, K. S.; Karlapati, S.; Mishra, J.; D, S.

    2015-12-01

    The Eastern Continental Margin of India (ECMI), a classical passive margin has evolved after breakup of the Indian landmass from the East Antarctica during the Early Cretaceous. Anomalous thick sediments and lack of cohesive magnetic signatures in the Bay of Bengal hampered delineation of rift-structure and age assignment for the continental breakup between India and East Antarctica. Further, absence of lithological and geochronological information and a few seismic profiles from the margin led to put forward several competing models for the rift initiation and evolution of the ECMI. Here, we analyze long streamer seismic reflection data and deep-water drill well information from the western Bay of Bengal to infer the buried rift structure, crustal architecture and stratigraphy along the ECMI. Following the structural pattern of the margin, the region is divided into four domains as decoupled, coupled, exhumed and oceanic, which in turn helped us to demarcate the variations in rift structure from south to north along the margin. The southern segment in the vicinity of Cauvery Basin consists of steep continental shelf associated with few major normal faults, which indicates that the segment was evolved as mix shear-rifted margin. The central segment off southern part of the Krishna-Godavari Basin is controlled by a series of fault-bounded half-graben structures and presence of thinned continental crust over the exhumed mantle body, revealing that the segment was formed under hyper-rifting process. While the northern segment extends up to Mahanadi Basin shows relatively less gradient continental slope with a few major faults, suggesting that the segment was evolved by hypo-extended process. Variable crustal architecture lying along the ECMI supports each segment of the margin formed in a specific rift process. A breakup unconformity considered as important geological constraint for completion of rift process between India and East Antarctica is clearly mapped on

  19. Structural Dimensions of Roma School Desegregation Policies in Central and Eastern Europe

    ERIC Educational Resources Information Center

    Rostas, Iulius; Kostka, Joanna

    2014-01-01

    Scrutiny of the socio-economic exclusion of the Roma in Central and Eastern Europe has brought attention to the widespread practice of school segregation of Romani children who are automatically placed in classes for the mentally disabled or shunted into separate and inferior schools and classrooms. It is now widely recognised that such practices…

  20. The Structural Disempowerment of Eastern European Migrant Farm Workers in Norwegian Agriculture

    ERIC Educational Resources Information Center

    Rye, Johan Fredrik; Andrzejewska, Joanna

    2010-01-01

    Since the 2004 EU enlargement established one European common labour market, a large number of Eastern Europeans have taken up seasonal employment as hired farm workers in Norwegian agriculture. Much attention in the public has been given to the potential for "social dumping" of these migrating workers, as they are considered prone to…

  1. Kinematics, crustal structure and seismotectonics of the subducting northernmost Luzon arc in eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Lee, Jian-Cheng; Chen, Chia-Yu; Chen, Rou-Fei; Chen, Yue-Gau; Chen, Horng-Yue

    2015-04-01

    The Coastal Range in eastern Taiwan belongs to the northernmost Luzon arc system, which sits on the western edge of the NW-moving Philippine Sea plates (PSP). As the PSP subducting and colliding with the Eurasian continental margin in Taiwan, the northern part of the Coastal Range provides a crucial key for better understand the geological structures and processes at tectonic transition from collision to subduction at plate corner. In this study, we conducted a dense network of GPS measurements at the northern tip of the Coastal Range and compiled available geological and geophysical information, including surface geomorphic features, geological structures, seismological data, seismic tomography, in order to provide insights on kinematics, crustal structure and seismotectonics of the transition from waning collision to subduction of the northern Luzon arc system and its vicinity. Regional short-term geodetic data, including GPS and levelling, and long-term thousand-year scale geological vertical rates indicate that the Coastal Range is going down toward the north, which we interpret it as being pulling down by the north- subduction PSP. Combing with the local GPS measurements carried out at the northern tip of the Longitudinal Valley, the plate suture, which shows a significant clockwise rotation at a rate of 33° M/yr, we interpret the tectonic escape of the northernmost Longitudinal Valley as being initiated locally by the northwest indentation of the Coastal Range, which pushed the northern Longitudinal Valley to move upward and eastward to form a 2-km-wide, 8-km-long, 100-m-high Milun Tableland. No significant deformation was observed across the surface trace of the major active Milun fault on the western side of the tableland, which has been ruptured during the 1951 M=7.1 Hualien earthquake, indicating that the Milun fault is now probably locked in the near surface. As for the crustal structure, we anticipate that there exists a fore-arc basement of the Luzon

  2. Low temperature thermochronology in the Eastern Alps: Implications for structural and topographic evolution

    PubMed Central

    Wölfler, Andreas; Stüwe, Kurt; Danišík, Martin; Evans, Noreen J.

    2012-01-01

    According to new apatite fission track, zircon- and apatite (U–Th)/He data, we constrain the near-surface history of the southeastern Tauern Window and adjacent Austrolapine units. The multi-system thermochronological data demonstrate that age-elevation correlations may lead to false implications about exhumation and cooling in the upper crust. We suggest that isothermal warping in the Penninic units that are in the position of a footwall, is due to uplift, erosion and the buildup of topography. Additionally we propose that exhumation rates in the Penninic units did not increase during the Middle Miocene, thus during the time of lateral extrusion. In contrast, exhumation rates of the Austroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this unit were not warped. The new zircon (U–Th)/He ages as well as zircon fission track ages from the literature document a Middle Miocene exhumation pulse which correlates with a period of enhanced sediment accumulation during that time. However, enhanced sedimentation- and exhumation rates at the Miocene/Pliocene boundary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for surface uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvious to explain surface uplift in the Eastern Alps. In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the Möll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik–Möll valley- and Mur–Mürz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg–Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc. PMID:27065501

  3. Low temperature thermochronology in the Eastern Alps: Implications for structural and topographic evolution.

    PubMed

    Wölfler, Andreas; Stüwe, Kurt; Danišík, Martin; Evans, Noreen J

    2012-05-14

    According to new apatite fission track, zircon- and apatite (U-Th)/He data, we constrain the near-surface history of the southeastern Tauern Window and adjacent Austrolapine units. The multi-system thermochronological data demonstrate that age-elevation correlations may lead to false implications about exhumation and cooling in the upper crust. We suggest that isothermal warping in the Penninic units that are in the position of a footwall, is due to uplift, erosion and the buildup of topography. Additionally we propose that exhumation rates in the Penninic units did not increase during the Middle Miocene, thus during the time of lateral extrusion. In contrast, exhumation rates of the Austroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this unit were not warped. The new zircon (U-Th)/He ages as well as zircon fission track ages from the literature document a Middle Miocene exhumation pulse which correlates with a period of enhanced sediment accumulation during that time. However, enhanced sedimentation- and exhumation rates at the Miocene/Pliocene boundary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for surface uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvious to explain surface uplift in the Eastern Alps. In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the Möll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik-Möll valley- and Mur-Mürz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg-Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc.

  4. Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Yan, En-Rong; Chen, Han Y. H.; Chang, Scott X.; Zhao, Yan-Tao; Yang, Xiao-Dong; Xu, Ming-Shan

    2016-08-01

    Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82 % of the variation in aboveground C storage, 55-59 % of the variation in stand structural diversity, and 0.1 to 9 % of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (β = 0.41), and a positive indirect effect via stand structural diversity (β = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (β = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and

  5. 20. GROVE OF TREES PINES, MULBERRY, JUNIPER, BLUE SPRUCE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. GROVE OF TREES -- PINES, MULBERRY, JUNIPER, BLUE SPRUCE -- TRANSPLANTED FROM NEW MEXICO MANZANO MOUNTAINS, WEST OF BUILDINGS 4 AND T-59, LOOKING NORTHWEST - U. S. Veterans Administration Medical Center, 2100 Ridgecrest Southeast, Albuquerque, Bernalillo County, NM

  6. 3. View from northeast corner, Canisteo and Spruce Streets. Photo ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View from northeast corner, Canisteo and Spruce Streets. Photo shows the garage area (Building #5) with sawtooth roofline and front elevation of Buildings #6 and #1. - Merrill Silk Mill, 233 Canisteo Street, Hornell, Steuben County, NY

  7. 36. Photocopied August 1978. SECTION III, LOOKING SOUTHWEST FROM SPRUCE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. Photocopied August 1978. SECTION III, LOOKING SOUTHWEST FROM SPRUCE STREET, JUNE 13, 1902, WITH TIMBER LINING ALMOST COMPLETED. (245) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  8. Diapause disruption with tebufenozide for early-instar control of the spruce budworm, Choristoneura fumiferana.

    PubMed

    Doucet, Daniel; Frisco, Caroline; Cusson, Michel; Bauce, Eric; Palli, Subba Reddy; Tomkins, Bill; Arif, Basil; Retnakaran, Arthur

    2007-08-01

    In North America, the eastern spruce budworm, Choristoneura fumiferana Clem., is an important coniferous pest against which tebufenozide has proven effective as a control product. By acting as an ecdysone agonist, tebufenozide can induce precocious moulting in late (fifth-sixth) instars but can also be carried over to the next generation owing to its persistence on foliage. The authors conducted laboratory experiments on first-instar larvae treated with tebufenozide dissolved in acetone. Larvae exposed to doses equal to or above 0.1 microg cm(-2) displayed precocious moulting in the second instar after hibernaculum spinning, which effectively disrupted diapause. Larger doses induced moulting in first instars. Evidence is provided that this dose-response difference is related to whether or not an effective dose of tebufenozide is ingested by the first instar prior to the peak of moulting hormone (20-hydroxyecdysone) in first instars. Doses ineffective to kill first instars are carried over to the second instar, where they induce a precocious moult. This type of response to tebufenozide is dependent on the presence of a moulting machinery (the EcR-USP receptor complex) that is ready for ecdysone transduction. Interestingly, ecdysone levels are low in second instars, as measured by a radioimmunoassay, which suggests that diapause in spruce budworm is maintained by a suppression of ecdysone production. Thus, diapause disruption by tebufenozide may well provide an alternative control strategy for this important pest.

  9. Pulpability of beetle-killed spruce. Forest Service research paper

    SciTech Connect

    Scott, G.M.; Bormett, D.W.; Sutherland, N.R.; Abubakr, S.; Lowell, E.

    1996-08-01

    Infestation of the Dendroctonus rufipennis beetle has resulted in large stands of dead and dying timber on the Kenai Peninsula in Alaska. Tests were conducted to evaluate the value of beetle-killed spruce as pulpwood. The results showed that live and dead spruce wood can be pulped effectively. The two least deteriorated classes and the most deteriorated class of logs had similar characteristics when pulped; the remaining class had somewhat poorer pulpability.

  10. Labeling Feral Spruce Budworm (Lepidoptera: Tortricidae) Populations With Rubidium.

    PubMed

    MacKinnon, Wayne; Eveleigh, Eldon; Silk, Peter; Forbes, Glen

    2016-04-01

    Rubidium (Rb) is a trace element that occurs naturally in low concentrations and is easily absorbed by plants, making it a useful tool for labeling insect defoliators, such as spruce budworm (Choristoneura fumiferana Clemens). Balsam fir trees (Abies balsamea (L.) Miller) injected with either 8 or 16 g per tree of rubidium chloride (RbCl) showed quick uptake and distribution throughout the crown, with no negative effects on tree shoot growth or spruce budworm survival and development. Adult spruce budworm that fed as larvae on trees injected with RbCl were clearly labeled, with significantly higher Rb concentrations than the background levels found in adults that fed as larvae on control trees. Rb concentrations in feral spruce budworm adults for both the 8 g (9 µg/g) and 16 g (25 µg/g) per tree treatments were at least five times lower than those in laboratory-reared adults on 1,000 µg/g RbCl diet (125 µg/g); survival, development, pupal weight, sex ratio, and mating status of spruce budworm were not adversely affected by Rb treatment. Egg masses laid by feral females that fed as larvae on Rb-labeled trees were also labeled with Rb. Injecting trees with RbCl is a viable technique for labeling feral spruce budworm populations to help distinguish local populations from immigrants to better evaluate the success of early intervention strategies such as mating disruption.

  11. Monoterpene emissions from bark beetle infested Engelmann spruce trees

    NASA Astrophysics Data System (ADS)

    Amin, Hardik S.; Russo, Rachel S.; Sive, Barkley; Richard Hoebeke, E.; Dodson, Craig; McCubbin, Ian B.; Gannet Hallar, A.; Huff Hartz, Kara E.

    2013-06-01

    Bark beetle infestation impacts the health of coniferous forests, which are an important source of volatile organic compounds (VOCs) to the atmosphere. The types and amounts of VOCs emitted from forests can influence secondary organic aerosol (SOA) formation and impact overall air quality. In this initial work, the impact of bark beetle infestation on SOA precursors from Engelmann spruce is assessed. The VOCs emitted from the trunk of infested and healthy spruce trees were sampled using both sorbent traps and evacuated canisters that were analyzed by gas chromatography/mass spectroscopy. The samples from the infested spruce tree suggest a nine-fold enhancement in the total VOC emissions. The dominant VOCs in the infested spruce trees were 3-carene, β-pinene, and α-pinene. The increase observed in VOCs sampled at the trunk of the infested spruce was consistent with increases observed at infested lodgepole pine trunks. However, the types and amounts of VOCs emitted from Engelmann spruce and lodgepole pine are different, which suggests that additional measures of VOC emissions are needed to characterize the impact of bark beetle infestation on VOC emissions and SOA precursors.

  12. Skate assemblage on the eastern Patagonian Shelf and Slope: structure, diversity and abundance.

    PubMed

    Arkhipkin, A; Brickle, P; Laptikhovsky, V; Pompert, J; Winter, A

    2012-04-01

    The eastern Patagonian Shelf and continental slope of the south-west Atlantic Ocean support a high biodiversity and abundance of skates. In this study, meso-scale differences in the assemblages, spatial and seasonal distributions of skates are revealed among six habitat zones of the eastern Patagonian Shelf characterized by distinctive oceanographic conditions. Most skates belonged to temperate fauna, and their abundance was much greater in habitats occupied by temperate waters (north-western outer shelf) or mixed waters (northern slope) than in habitats occupied by sub-Antarctic waters (SASW) (south-eastern outer shelf and southern slope). Sub-Antarctic skates were not abundant on the shelf even in habitats occupied by SASW, occurring mainly in deep areas of the lower continental slope. The majority of temperate skates migrated seasonally, shifting northward in winter and spreading southward with warming waters in summer. Most temperate species had two peaks in female maturity (mainly spring and autumn) and spawned in the same habitats where they fed. It is hypothesized that the high biodiversity and abundance of skates on the Patagonian Shelf and Slope are due to the practical absence of their natural competitors, flatfishes, which occupy similar eco-niches elsewhere.

  13. Orogen-perpendicular structures in the central Tasmanides and implications for the Paleozoic tectonic evolution of eastern Australia

    NASA Astrophysics Data System (ADS)

    Abdullah, Rashed; Rosenbaum, Gideon

    2017-01-01

    The curvilinear E-W structures of the southern Thomson Orogen are approximately orthogonal to the general N-S structural trend of the Tasmanides of eastern Australia. The origin of these orogen-perpendicular structures and their implications to tectonic reconstructions of eastern Gondwana are not fully understood. Here we use geophysical data to unravel the geometry, kinematics and possible timing of major structures along the boundary between the Thomson Orogen and the southern Tasmanides (Delamerian and Lachlan orogens). Aeromagnetic data from the southern Thomson Orogen show WNW, E-W and/or ENE trending structural grains, corresponding to relatively long wavelength linear geophysical anomalies. Kinematic analyses indicate strike-slip and transpressional deformation along these geophysically defined faults. Structural relationships indicate that faulting took place during the Benambran (Late Ordovician to Middle Silurian) and Tabberabberan (late Early to Middle Devonian) orogenies. However, some of the described crustal-scale structures may have developed in the Cambrian during the Delamerian Orogeny. Interpretation of deep seismic data shows that the crust of the southern Thomson Orogen is substantially thicker than the Lachlan Orogen crust, which is separated from the Thomson Orogen by the north-dipping Olepoloko Fault. A major lithospheric-scale change across this boundary is also indicated by a contrast in seismic velocities. Together with evidence for the occurrence of Delamerian deformation in both the Koonenberry Belt and northeastern Thomson Orogen, and a significant contrast in the width of the northern Tasmanides versus the southern Tasmanides, it appears that the southern Thomson Orogen may represent the locus of orogen-perpendicular segmentation, which may have occurred in response to along-strike plate boundary variations.

  14. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming.

    PubMed

    Girardin, Martin P; Hogg, Edward H; Bernier, Pierre Y; Kurz, Werner A; Guo, Xiao Jing; Cyr, Guillaume

    2016-02-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography, and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2 ], on the aboveground productivity of black spruce forests across Canada south of 60°N for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially explicit simulations of net primary productivity (NPP) and its drivers, and multivariate statistical modeling. We found that soil water availability is a significant driver of black spruce interannual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Interannual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on interannual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree-ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations.

  15. Climate-growth relationships for bog-grown black spruce in northern Minnesota

    SciTech Connect

    Vogel, K.J. )

    1993-06-01

    Black spruce (Picea mariana) tree-ring chronologies were derived for three bogs in northern Minnesota. Standard chronologies were highly intercorrelated (0.72 to 0.87). The ring-width variability attributable to a common signal ranged from 38.6 to 56.8 percent which is large for closed canopy eastern forests. These chronologies exhibited great serial correlation, therefore all chronologies were autoregressively modelled prior to climatic analyses. Each chronology was compared to monthly temperature and precipitation data from a nearby weather station. Strengths of linear relationships were measured by the product-moment correlation coefficient. May and August temperatures from the previous year and March precipitation of the current year were significantly correlated with ring-width indices. These data suggest that tree-ring chronologies from mid-continental peatlands may be a valuable, though presently ignored, source of paleoclimatic data.

  16. Structural differences between the western and eastern Qiongdongnan Basin: evidence of Indochina block extrusion and South China Sea seafloor spreading

    NASA Astrophysics Data System (ADS)

    Zhang, Cuimei; Wang, Zhenfeng; Sun, Zhipeng; Sun, Zhen; Liu, Jianbao; Wang, Zhangwen

    2013-12-01

    Located at the intersection between a NW-trending slip system and NE-trending rift system in the northern South China Sea, the Qiongdongnan Basin provides key clues for us to understand the proposed extrusion of the Indochina Block along with Red River Fault Zone and extensional margins. In this paper we for the first time systematically reveal the striking structural differences between the western and eastern sector of the Qiongdongnan Basin. Influenced by the NW-trending slip faults, the western Qiongdongnan Basin developed E-W-trending faults, and was subsequently inverted at 30-21 Ma. The eastern sector was dominated by faults with NE orientation before 30 Ma, and thereafter with various orientations from NE, to EW and NW during the period 30-21 Ma; rifting display composite symmetric graben instead of the composite half graben or asymmetric graben in the west. The deep and thermal structures in turn are invoked to account for such deformation differences. The lithosphere of the eastern Qiongdongnan Basin is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed and the faults varied with the basal plate boundary. However, the Southern and Northern Uplift area and middle of the central depression is located on normal lithosphere and formed half grabens or simple grabens. The lithosphere in the western sector is transitional from very hot to normal. Eventually, the Paleogene tectonic development of the Qiongdongnan Basin may be summarized into three stages with dominating influences, the retreat of the West Pacific subduction zone (44-36 Ma), slow Indochina block extrusion together with slab-pull of the Proto-South China Sea (36-30 Ma), rapid Indochina block extrusion together with the South China Sea seafloor spreading (30-21 Ma).

  17. Vertical and horizontal transport of energy and matter by coherent motions in a tall spruce canopy

    NASA Astrophysics Data System (ADS)

    Serafimovich, A.; Siebicke, L.; Foken, T.

    2009-04-01

    In a forested ecosystem low frequency coherent events contribute significantly to the budgets of momentum, heat and matter. In the frame of EGER (ExchanGE processes in mountainous Regions) project the contribution of coherent structures to the vertical and horizontal transfer of energy and matter in a tall spruce canopy was investigated. Two measuring campaigns were carried out in North-Eastern Bavaria at the Waldstein site in the Fichtelgebirge mountains. Observations of coherent structures were obtained by a vertical profile of sonic anemometers equipped with fast CO2 and H2O analyzers covering all parts of the forest up to the lower part of the roughness sub layer. In addition five small masts were set up in the trunk space of the forest and equipped with sonic anemometers, humidity and temperature sensors as well as CO2 analyzers. Combination of measurements done in vertical and horizontal directions allows us to investigate coherent structures, their temporal scales, their role in flux transport and vertical coupling between the subcanopy, canopy and air above the canopy level. To extract coherent structures from the turbulent time series, the technique based on the wavelet transform has been used. Conditional sampling analysis showed a domination of coherent structure signatures in vertical wind measurements with probable temporal scales in the order of 10 s to 30 s. The mean temporal scale of coherent structures detected in the trunk space of the forest was 30 - 40 s. The number of coherent structures detected at the slim and tall tower was found to be 40% less than the number of coherent structures detected at the heavy main tower. In contrast to the slim tower the main tower is more massive and was equipped with more instruments resulting for additional generation of turbulence. The Reynolds-averaged flux and flux contribution of coherent structures were derived using a triple decomposition for the detected and conditionally averaged time series, when

  18. Soil-solution chemistry in a low-elevation spruce-fir ecosystem, Howland, Maine

    USGS Publications Warehouse

    Fernandez, Ivan J.; Lawrence, Gregory B.; Son, Yowhan

    1995-01-01

    Soil solutions were collected monthly by tension and zero-tension lysimeters in a low-elevation red spruce stand in east-central Maine from May 1987 through December 1992. Soil solutions collected by Oa tension lysimeters had higher concentrations of most constituents than the Oa zero-tension lysimeters. In Oa horizon soil solutions growing season concentrations for SO4, Ca, and Mg averaged 57, 43, and 30 μmol L−1 in tension lysimeters, and 43, 28, and 19 μmol L−1 in zero-tension lysimeters, respectively. Because tension lysimeters remove water held by the soil at tensions up to 10 kPa, solutions are assumed to have more time to react with the soil compared to freely draining solutions collected by zero-tension lysimeters. Solutions collected in the Bs horizon by both types of collectors were similar which was attributed to the frequency of time periods when the water table was above the Bs lysimeters. Concentrations of SO4 and NO3 at this site were lower than concentrations reported for most other eastern U.S. spruce-fir sites, but base cation concentrations fell in the same range. Aluminum concentrations in this study were also lower than reported for other sites in the eastern U.S. and Ca/Al ratios did not suggest inhibition of Ca uptake by roots. Concentrations of SO4, Ca, K, and Cl decreased significantly in both the Oa and Bs horizons over the 56-month sampling period, which could reflect decreasing deposition rates for sulfur and base cations, climatic influences, or natural variation. A longer record of measured fluxes will be needed to adequately define temporal trends in solution chemistry and their causes.

  19. The Genetic Structure of Wild Orobanche cumana Wallr. (Orobanchaceae) Populations in Eastern Bulgaria Reflects Introgressions from Weedy Populations

    PubMed Central

    Pineda-Martos, Rocío; Pujadas-Salvà, Antonio J.; Fernández-Martínez, José M.; Stoyanov, Kiril; Pérez-Vich, Begoña

    2014-01-01

    Orobanche cumana is a holoparasitic plant naturally distributed from central Asia to south-eastern Europe, where it parasitizes wild Asteraceae species. It is also an important parasitic weed of sunflower crops. The objective of this research was to investigate genetic diversity, population structure, and virulence on sunflower of O. cumana populations parasitizing wild plants in eastern Bulgaria. Fresh tissue of eight O. cumana populations and mature seeds of four of them were collected in situ on wild hosts. Genetic diversity and population structure were studied with SSR markers and compared to weedy populations. Two main gene pools were identified in Bulgarian populations, with most of the populations having intermediate characteristics. Cross-inoculation experiments revealed that O. cumana populations collected on wild species possessed similar ability to parasitize sunflower to those collected on sunflower. The results were explained on the basis of an effective genetic exchange between populations parasitizing sunflower crops and those parasitizing wild species. The occurrence of bidirectional gene flow may have an impact on wild populations, as new physiological races continuously emerge in weedy populations. Also, genetic variability of wild populations may favour the ability of weedy populations to overcome sunflower resistance mechanisms. PMID:25143963

  20. STRUCTURAL AND HYDROGEOLOGIC APPLICATIONS OF REMOTE SENSING DATA, EASTERN YUCATAN PENINSULA, MEXICO.

    USGS Publications Warehouse

    Southworth, C. Scott; ,

    1984-01-01

    Landsat and Seasat satellite images and aerial photographs of eastern Yucatan Peninsula, Mexico, were analyzed to delineate geologic controls of ground water. Significant interpretation results include the delineation of linear topographic swales, interpreted as fractures, extending more than 50 km along strike from the previously known limit of the Holbox fracture system; the alignment of sink holes (cenotes) and inlets (caletas) on strike with existing faults and fracture systems; and the identification of tonal anomalies in Ingles Lagoon suggesting fresh-water discharge from a submarine spring.

  1. Mechanical properties of spruce wood cell walls by nanoindentation

    NASA Astrophysics Data System (ADS)

    Gindl, W.; Gupta, H. S.; Schöberl, T.; Lichtenegger, H. C.; Fratzl, P.

    2004-12-01

    In order to study the effects of structural variability, nanoindentation experiments were performed in Norway spruce cell walls with highly variable cellulose microfibril angle and lignin content. Contrary to hardness, which showed no statistically significant relationship with changing microfibril angle and lignin content, the elastic modulus of the secondary cell wall decreased significantly with increasing microfibril angle. While the elastic moduli of cell walls with large microfibril angle agreed well with published values, the elastic moduli of cell walls with small microfibril angle were clearly underestimated in nanoindentation measurements. Hardness measurements in the cell corner middle lamella allowed us to estimate the yield stress of the cell-wall matrix to be 0.34±0.16 GPa. Since the hardness of the secondary cell wall was statistically not different from the hardness of the cell corner middle lamella, irrespective of high variability in cellulose microfibril angle, it is proposed that compressive yielding of wood-cell walls is a matrix-dominated process.

  2. Restoration of the depression structure at the eastern part of central Kyushu, Japan by means of dislocation modeling

    NASA Astrophysics Data System (ADS)

    Kusumoto, Shigekazu; Takemura, Keiji; Fukuda, Yoichi; Takemoto, Shuzo

    1999-02-01

    We have attempted to restore a subsurface structure in the eastern part of central Kyushu, Japan, by combining fault motions which were modeled as dislocation planes embedded in an elastic isotropic half space. The simulated crustal deformation pattern was compared with the subsurface structures estimated from gravity anomalies and/or seismic prospecting. The modeling procedure successfully restored all tectonic basins in the area without any need for motive forces for uplift or subsidence. The results also suggest that two major tectonic events have occurred in this region. Those are (1) the formation of half-graben caused by north-south extension, and (2) the formation of the pull-apart basin caused by east-west compression.

  3. Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France

    PubMed Central

    Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs on behalf of CarbaFrEst Group, Christophe

    2015-01-01

    Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates’ clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised. PMID:26557115

  4. Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France.

    PubMed

    Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs On Behalf Of CarbaFrEst Group, Christophe

    2015-01-01

    Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates' clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised.

  5. 75 FR 39691 - Announcement To Extend the Recommended Determination Preparation Period for the Spruce No. 1...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Announcement To Extend the Recommended Determination Preparation Period for the Spruce No. 1... the Spruce No. 1 Proposed Determination or prepare a Recommended Determination within 30 days...

  6. Decline of red spruce in the Adirondacks, New York

    SciTech Connect

    Scott, J.T.; Siccama, T.G.; Johnson, A.H.; Breisch, A.R.

    1984-01-01

    Thirty-two stands in the spruce-fir forests of Whiteface Mountain in the Adirondacks, originally sampled from 1964-66, were resurveyed in 1982. From 10-25 Bitterlich points were used in each stand in 1982 to obtain an estimate of basal area per hectare. Data were summarized for low elevation (<900m) and high elevation (> or = 900m) forests. Red spruce declined by 40-60% in basal area for the low elevation forests and by 60-70% above 900m. Balsam fir decreased by 35% at high elevations, due to natural disturbance in several of the stands, but was unchanged when only undisturbed stands were considered. The decline of red spruce accounted for about three quarters of the total decrease in basal area for both the high- and low-elevation forests. Spruce seedling frequency for the high-elevation sample decreased by 80%, but was unchanged below 900m. The pattern of spruce decline in the Adirondacks is similar to findings for New England. The cause of the decline is speculative at the time.

  7. Mathematical Methods of Modelling the Morphology of Spruce Trees

    NASA Astrophysics Data System (ADS)

    Janoutová, Růžena; Novotný, Jan; Pivovarník, Marek; Zemek, František

    2014-05-01

    Radiative transfer (RT) models are simulation tools which can be used to quantify relationships between vegetation canopy properties and observed remotely sensed data. This study aims at creating a spruce tree growth model as a key input for use in RT models. The spruce tree model is built on data obtained from terrestrial laser scanning of spruce trees. Each tree model is unique. This uniqueness is achieved by using L-systems which are able to simulate natural randomness while complying with the given tree parameters. L-systems are established on a theory of grammar that enables rewriting a string of symbols according to specified rewriting rules. In practice, our tree models are generated in Blender visualization software, implementing an algorithm written in Python. The algorithm generates the basic parameters of the whole tree and then creates the parameters of the spruce trunk and initial branches. The parameters are generated randomly within a range that is calculated from measured data. Then each branch is grown on the basis of annual increments defined by field measurements. Tree needles are distributed with respect to the age of individual branches; therefore, the needles have different colors according to their age. Cones and faces are graphical representations of the spruce model. Branches are represented by cones and needles are represented by faces around the branches. The faces are transparent, thus simulating light transmittance in-between the needles. The whole model is highly computationally demanding, especially with respect to computer memory.

  8. Structural geometry in the eastern Pyrenees and western Gulf of Lion (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Mauffret, Alain; Durand de Grossouvre, Bernard; Tadeu Dos Reis, Antonio; Gorini, Christian; Nercessian, Alex

    2001-11-01

    We present new seismic data from the Gulf of Lion located east of the Pyrenees on the continental shelf of the Mediterranean Sea. The deep penetration LISA (Ligurian-Sardinia Sea) seismic lines, the shots of the LISA cruise recorded on land, and the high definition ELF seismic sections allow us to present a complete picture of the tectonics in this area from the surface to the Moho level, and also to document late Miocene-early Pliocene extensional tectonics in the area. Previous studies show a prominent thinning of the crust observed from the Pyrenees towards the Gulf of Lion. The Moho depth varies from 48 km beneath the Axial Range crust (thickened during the Pyrenean Eocene Orogeny) to 21 km below the Catalan Basin in the Gulf of Lion. This crustal thinning occurred mainly during the early Miocene extension of the Mediterranean Sea. Balanced reconstructed geological sections derived from reflection and refraction seismic data allow us to evaluate the stretching factors at the crustal level. A maximum extension of 25 km is computed for the Catalan Basin area. This extension is related to detachments that penetrate the crust as deep as 11 km to the base of the brittle crust. These intra basement detachments have been confused in the past with the Paleozoic acoustic basement. The detachments show a clear listric shape and the geometry of horst and grabens can be explained by a hanging wall and footwall configuration with isostatic rebound of the footwall. The uplift in the Eastern Pyrenees (Albères and Canigou Massifs), on the other hand, is related to the late Miocene-early Pliocene extension we mapped in the area. These elevated features, probably formed by isostatic rebound, are surrounded by deep basins such as the Roussillon and El Empordà depressions. A 1.7 km uplift during the late Miocene-early Pliocene is computed in the offshore part of the Albères Massif. The cause of this Late Miocene-early Pliocene extension is not well explained although an uplift

  9. Structural characteristic and origin of intra-continental fold belt in the eastern Sichuan basin, South China Block

    NASA Astrophysics Data System (ADS)

    Li, Chuanxin; He, Dengfa; Sun, Yanpeng; He, Jinyou; Jiang, Zaixing

    2015-11-01

    The fold-and-thrust belt in the eastern Sichuan basin is represented by a series of subparallel chevron anticlines. Under the orogenic tectonic setting within the South China Block in Meso-Cenozoic period and the influence of the multi-layer detachment fault, the deformation of the thrust belt exhibits remarkably layered and large-scale intracontinental thrusting structural characteristics. In this paper, we focus on the structural geometry and deformational mechanisms using the latest two-dimensional (2D) and three-dimensional (3D) seismic reflection data in combination with well and outcrop data. The multi-layer detachment faults, especially the upper gypsum-bearing detachment in the Middle Triassic Jialingjiang Formation and lower detachment with gypsum or shale in the Lower-Middle Cambrian system, directly control the deformational styles of the study area. Interpretation of seismic sections indicates that the fold-and-thrust belt has various deformational styles during folding, including fault-propagation fold, fault-bend fold, and detachment fold with box-fold or pop-up structural geometry. Regional location and structural boundaries play significant roles in controlling the deformational styles, and distinct differences exist among the different anticlines. The Huayingshan anticline located at the front of the thrust belt shows intense structural deformation with northwestward thrusting direction and a relatively weak opposite southeastward thrusting. In addition, the anticlines exhibit structural differences along strike and the fold-and-thrust belt in the northern segment is influenced by the North China Block.

  10. Experimental warming delays autumn senescence in a boreal spruce bog: Initial results from the SPRUCE experiment

    NASA Astrophysics Data System (ADS)

    Richardson, Andrew; Furze, Morgan; Aubrecht, Donald; Milliman, Thomas; Nettles, Robert; Krassovski, Misha; Hanson, Paul

    2016-04-01

    Phenology is considered one of the most robust indicators of the biological impacts of global change. In temperate and boreal regions, long-term data show that rising temperatures are advancing spring onset (e.g. budburst and flowering) and delaying autumn senescence (e.g. leaf coloration and leaf fall) in a wide range of ecosystems. While warm and cold temperatures, day length and insolation, precipitation and water availability, and other factors, have all been shown to influence plant phenology, the future response of phenology to rising temperatures and elevated CO2 still remains highly uncertain because of the challenges associated with conducting realistic manipulative experiments to simulate future environmental conditions. At the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) experiment in the north-central United States, experimental temperature (0 to +9° C above ambient) and CO2 (ambient and elevated) treatments are being applied to mature, and intact, Picea mariana-Sphagnum spp. bog communities in their native habitat through the use of ten large (approximately 12 m wide, 10 m high) open-topped enclosures. We are tracking vegetation green-up and senescence in these chambers, at both the individual and whole-community level, using repeat digital photography. Within each chamber, digital camera images are recorded every 30 minutes and uploaded to the PhenoCam (http://phenocam.sr.unh.edu) project web page, where they are displayed in near-real-time. Image processing is conducted nightly to extract quantitative measures of canopy color, which we characterize using Gcc, the green chromatic coordinate. Data from a camera mounted outside the chambers (since November 2014) indicate strong seasonal variation in Gcc for both evergreen shrubs and trees. Shrub Gcc rises steeply in May and June, and declines steeply in September and October. By comparison, tree Gcc rises gradually from March through June, and declines gradually from

  11. Blue whale population structure along the eastern South Pacific Ocean: evidence of more than one population.

    PubMed

    Torres-Florez, J P; Hucke-Gaete, R; LeDuc, R; Lang, A; Taylor, B; Pimper, L E; Bedriñana-Romano, L; Rosenbaum, H C; Figueroa, C C

    2014-12-01

    Blue whales (Balaenoptera musculus) were among the most intensively exploited species of whales in the world. As a consequence of this intense exploitation, blue whale sightings off the coast of Chile were uncommon by the end of the 20th century. In 2004, a feeding and nursing ground was reported in southern Chile (SCh). With the aim to investigate the genetic identity and relationship of these Chilean blue whales to those in other Southern Hemisphere areas, 60 biopsy samples were collected from blue whales in SCh between 2003 and 2009. These samples were genotyped at seven microsatellite loci and the mitochondrial control region was sequenced, allowing us to identify 52 individuals. To investigate the genetic identity of this suspected remnant population, we compared these 52 individuals to blue whales from Antarctica (ANT, n = 96), Northern Chile (NCh, n = 19) and the eastern tropical Pacific (ETP, n = 31). No significant differentiation in haplotype frequencies (mtDNA) or among genotypes (nDNA) was found between SCh, NCh and ETP, while significant differences were found between those three areas and Antarctica for both the mitochondrial and microsatellite analyses. Our results suggest at least two breeding population units or subspecies exist, which is also supported by other lines of evidence such as morphometrics and acoustics. The lack of differences detected between SCh/NCh/ETP areas supports the hypothesis that eastern South Pacific blue whales are using the ETP area as a possible breeding area. Considering the small population sizes previously reported for the SCh area, additional conservation measures and monitoring of this population should be developed and prioritized.

  12. Structure, Aboveground Biomass, and Soil Characterization of Avicennia marina in Eastern Mangrove Lagoon National Park, Abu Dhabi

    NASA Astrophysics Data System (ADS)

    Alsumaiti, Tareefa Saad Sultan

    Mangrove forests are national treasures of the United Arab Emirates (UAE) and other arid countries with limited forested areas. Mangroves form a crucial part of the coastal ecosystem and provide numerous benefits to society, economy, and especially the environment. Mangrove trees, specifically Avicennia marina, are studied in their native habitat in order to characterize their population structure, aboveground biomass, and soil properties. This study focused on Eastern Mangrove Lagoon National Park in Abu Dhabi, which was the first mangrove protected area to be designated in UAE. In situ measurements were collected to estimate Avicennia marina status, mortality rate (%), height (m), crown spread (m), stem number, diameter at breast height (cm), basal area (m), and aboveground biomass (t ha-1 ). Small-footprint aerial light detection and ranging (LIDAR) data acquired by UAE were processed to characterize mangrove canopy height and aboveground biomass density. This included extraction of LIDAR-derived height percentile statistics, segmentation of the forest into structurally homogenous units, and development of regression relationships between in situ reference and remote sensing data using a machine learning approach. An in situ soil survey was conducted to examine the soils' physical and chemical properties, fertility status, and organic matter. The data of soil survey were used to create soil maps to evaluate key characteristics of soils, and their influence on Avicennia marina in Eastern Mangrove Lagoon National Park. The results of this study provide new insights into Avicennia marina canopy population, structure, aboveground biomass, and soil properties in Abu Dhabi, as data in such arid environments is lacking. This valuable information can help in managing and preserving this unique ecosystem.

  13. Possible red spruce decline: Contributions of tree-ring analysis

    SciTech Connect

    Van Deusen, P.C. ); Reams, G.A. ); Cook, E.R. )

    1991-01-01

    Debate continues about the cause of apparent unprecedented decreases in ring width at all elevations, and increasing levels of mortality at high elevations, in red spruce (Picea rubens) stands in the northeastern United States. These growth and mortality trends are often used as evidence of red spruce decline, but the possibility remains that they may be occurring naturally. Two hypotheses are being used to explain the causes of red spruce growth reduction across its range and increased levels of standing dead at some high-elevation sites. This article summarizes the basic evidence used by advocates of these hypotheses and discusses the strengths of their arguments. The information presented is based primarily on tree-ring studies sponsored by the Forest Response Program, which is part of the National Acid Precipitation Assessment Program.

  14. Excess growing-season water limits lowland black spruce productivity

    NASA Astrophysics Data System (ADS)

    Dymond, S.; Kolka, R. K.; Bolstad, P. V.; Gill, K.; Curzon, M.; D'Amato, A. W.

    2015-12-01

    The annual growth of many tree species is limited by water availability, with growth increasing as water becomes less scarce. In lowland bogs of northern Minnesota, however, black spruce (Picea mariana) is often exposed to excess water via high water table elevations. These trees grow in thick deposits of organic mucky peat and often have shallow rooting systems to avoid the complete submersion of roots in water. While it is generally believed that black spruce decrease growth rates with rising water table elevations, this hypothesis has not been tested in situ. We used a unique, 50-year record of daily bog water table elevations at the Marcell Experimental Forest (MEF) in northern Minnesota to investigate the relationship between climate and black spruce productivity. Nine 1/20th ha circular plots were established in five different bogs and tree height, diameter-at-breast-height (DBH), and crown class were recorded. Additionally, two perpendicular cores were collected on all trees greater than 10 cm diameter-at-breast-height. Tree cores were sanded, mounted, cross-dated, and de-trended according to standard dendrochronological procedures. Ring width measurements were correlated with precipitation, temperature, and water table elevation using package BootRes in R to determine the climatic variables most associated with stand level productivity. Across the different plots, we found that early growing season water table elevation (May and June) was negatively correlated with both individual and stand-level black spruce growth (p < 0.01), while growth was positively correlated with March temperatures (p < 0.01). No significant relationships existed between black spruce growth and monthly precipitation. If summer water table elevations in these peatland ecosystems rise as is anticipated with more extreme precipitation events due to climate change, we could see an overall decrease in the stand level productivity of black spruce.

  15. Population structure of guppies in north-eastern Venezuela, the area of putative incipient speciation

    PubMed Central

    2014-01-01

    Background Geographic barriers to gene flow and divergence among populations in sexual traits are two important causes of genetic isolation which may lead to speciation. Genetic isolation may be facilitated if these two mechanisms act synergistically. The guppy from the Cumaná region (within the Cariaco drainage) of eastern Venezuela has been previously described as a case of incipient speciation driven by sexual selection, significantly differentiated in sexual colouration and body shape from the common guppy, Poecilia reticulata. The latter occurs widely in northern Venezuela, including the south-eastern side of Cordillera de la Costa, where it inhabits streams belonging to the San Juan drainage. Here, we present molecular and morphological analyses of differentiation among guppy populations in the Cariaco and San Juan drainages. Our analyses are based on a 953 bp long mtDNA fragment, a set of 15 microsatellites (519 fish from 20 populations), and four phenotypic traits. Results Both microsatellite and mtDNA data showed that guppies inhabiting the two drainages are characterised by a significant genetic differentiation, but a higher proportion of the genetic variance was distributed among populations within regions. Most guppies in the Cariaco drainage had mtDNA from a distinct lineage, but we also found evidence for widespread introgression of mtDNA from the San Juan drainage into the Cariaco drainage. Phenotypically, populations in the two regions differed significantly only in the number of black crescents. Phenotypic clustering did not support existence of two distinct groupings, but indicated a degree of distinctiveness of Central Cumaná (CC) population. However, CC population showed little differentiation at the neutral markers from the proximate populations within the Cariaco drainage. Conclusions Our findings are consistent with only partial genetic isolation between the two geographic regions and indicate that the geographic barrier of Cordillera de

  16. Genetic uniformity and the decline of red spruce

    SciTech Connect

    Not Available

    1989-05-01

    This brief note examines current research that suggests genetic uniformity as a cause of red spruce decline. Although acid rain and ozone have been implicated in the decline of the species, dieback has been observed evening areas where pollution is low. In addition, the dieback is not observed in other species. Researchers have analyzed the seeds of approximately 500 red spruce trees representing 13 boreal and Montane populations from southern Appalachia to Canada. Of 42 gene loci examined, on the average only 8% of the genes were heterozygousand only 31% were polymorphic.

  17. Influence of structural setting on sulphur isotopes in Archean orogenic gold deposits, Eastern Goldfields Province, Yilgarn, Western Australia

    NASA Astrophysics Data System (ADS)

    Hodkiewicz, P. F.; Groves, D. I.; Davidson, G. J.; Weinberg, R. F.; Hagemann, S. G.

    2009-02-01

    The published mean δ34S values of ore-related pyrites from orogenic gold deposits of the Eastern Goldfields Province, Yilgarn Craton lie between -4‰ and +4‰. As for orogenic gold deposits worldwide, most deposits have positive means and a restricted range of δ34S values, but some have negative means and wider ranges of δ34S values. Wall-rock carbonation and back-mixing of similar-source fluids with different fluid pathways can explain some of the more negative δ34S signatures. However, structural setting appears to be the most important factor controlling ore-fluid oxidation state and hence the distribution of δ34S values in gold-related pyrites. Shear-hosted deposits appear to have experienced fluid-dominated processes such as phase separation, whereas stockwork, vein-hosted or disseminated deposits formed under conditions of greater rock buffering. At Victory-Defiance, in particular, negative δ34S values are more common in gently dipping dilational structures, compared to more compressional steeply dipping structures. It appears most likely that fluid-pressure fluctuations during fault-valve cycles establish different fluid-flow regimes in structures with different orientations. Rapid fluid-pressure fluctuations in dilational structures during seismic activity can cause partitioning of reduced gas phases from the ore fluid during extreme phase separation and hence are an effective method of ore-fluid oxidation, leading to large, local fluctuations in oxidation state. It is thus not necessary to invoke mixing with oxidised magmatic fluids to explain δ34S signatures indicative of oxidation. In any case, available, robust geochronology in the Eastern Goldfields Province does not support the direct involvement of oxidised magmatic fluids from adjacent granitic intrusions in orogenic gold genesis. Thus, negative mean δ34S values and large variations in δ34S values of ore-related pyrites in world-class orogenic gold deposits are interpreted to result from

  18. Mother–offspring distances reflect sex differences in fine-scale genetic structure of eastern grey kangaroos

    PubMed Central

    King, Wendy J; Garant, Dany; Festa-Bianchet, Marco

    2015-01-01

    Natal dispersal affects life history and population biology and causes gene flow. In mammals, dispersal is usually male-biased so that females tend to be philopatric and surrounded by matrilineal kin, which may lead to preferential associations among female kin. Here we combine genetic analyses and behavioral observations to investigate spatial genetic structure and sex-biased dispersal patterns in a high-density population of mammals showing fission–fusion group dynamics. We studied eastern grey kangaroos (Macropus giganteus) over 2 years at Wilsons Promontory National Park, Australia, and found weak fine-scale genetic structure among adult females in both years but no structure among adult males. Immature male kangaroos moved away from their mothers at 18–25 months of age, while immature females remained near their mothers until older. A higher proportion of male (34%) than female (6%) subadults and young adults were observed to disperse, although median distances of detected dispersals were similar for both sexes. Adult females had overlapping ranges that were far wider than the maximum extent of spatial genetic structure found. Female kangaroos, although weakly philopatric, mostly encounter nonrelatives in fission–fusion groups at high density, and therefore kinship is unlikely to strongly affect sociality. PMID:26045958

  19. Eastern Aphrodite Terra on Venus - Characteristics, structure, and mode of origin

    NASA Technical Reports Server (NTRS)

    Crumpler, L. S.

    1990-01-01

    Altimetric and radar-image cross-strike discontinuities (CSDs) are found to cut across the nearly east-west strike of Eastern Aphrodite (EA) Terra, dividing or segmenting it into offset domains. Each of these domains is characterized by a discontinuous central chasma or trough. These features have been mapped in the altimetric and radar image data of EA on the basis of abrupt termination of riftlike central chasma, offset, and segmentation of the center highlands, and radar image discontinuities previously mapped in Western Aphrodite in terms of length, orientation, and influence on the central highlands and adjacent lowlands. It is concluded that EA displays a variety of geological and geophysical characteristics similar to those occuring at divergent boundaries. The surface map characteristics are the result of a great horizontal motion of the crust diverging from a well-defined linear region, a process that can occur whether the surface is part of a thick and strong plate detached from mantle convection or part of a thin and weak layer attached to a deep convective limb.

  20. Effectiveness of polyethylene sheeting in controlling spruce beetles ( coleoptera: scolytidae') in infested stacks of spruce firewood in Alaska. Forest Service research paper

    SciTech Connect

    Holsten, E.H.; Werner, R.A.

    1993-06-01

    The covering stacks of spruce firewood with either clear or black polyethylene sheeting does not raise log temperatures high enough to kill spruce beetle brood in the logs. Based on the results of the study, the authors do not recommend the use of polyethylene sheeting as a remedial measure for the reduction of spruce beetle brood in infested firewood or log decks in south-central Alaska.

  1. Paleoseismological analysis of an intraplate extensional structure: the Concud fault (Iberian Chain, eastern Spain)

    NASA Astrophysics Data System (ADS)

    Lafuente, P.; Arlegui, L. E.; Liesa, C. L.; Simón, J. L.

    2011-10-01

    The Concud fault is a 13.5 km long, NW-SE striking normal fault at the eastern Iberian Chain. Its recent (Late Pleistocene) slip history is characterized from mapping and trench analysis and discussed in the context of the accretion/incision history of the Alfambra River. The fault has been active since Late Pliocene times, with slip rates ranging from 0.07 to 0.33 mm/year that are consistent with its present-day geomorphologic expression. The most likely empirical correlation suggests that the associated paleoseisms have potential magnitudes close to 6.8, coseismic displacements of 2.0 m, and recurrence intervals from 6.1 to 28.9 ka. At least six paleoseismic events have been identified between 113 and 32 ka. The first three events (U to W) involved displacement along the major fault plane. The last three events (X to Z) encompassed downthrow and hanging-wall synthetic bending prompting fissure opening. This change is accompanied by a decrease in slip rate (from 0.63 to 0.08-0.17 mm/year) and has been attributed to activation of a synthetic blind fault at the hanging wall. The average coseismic displacement (1.9-2.0 m) and recurrence period (6.7-7.9 ka) inferred from this paleoseismic succession are within the ranges predicted from empirical correlation. Such paleoseismic activity contrasts with the moderate present-day seismicity of the area (maximum instrumental Mb = 4.4), which can be explained by the long recurrence interval that characterizes intraplate regions.

  2. Crustal structure of the eastern Qinling orogenic belt and implication for reactivation since the Cretaceous

    NASA Astrophysics Data System (ADS)

    Guo, Zhen; Chen, Y. John

    2016-06-01

    A high resolution crustal model of the eastern Qinling belt and central North China Craton (central NCC) is obtained along a N-S trending profile (corridor) by joint inversion of surface wave and receiver function. The NCC is one of the oldest cratons on Earth and the Qinling belt is the suture zone between the NCC and South China block (SCB). The Qinling belt is characterized by low crustal velocity (< 3.6 km/s) as well as low bulk Vp/Vs ratio (1.66-1.8), suggesting that the mid- to lower crust is predominantly felsic in composition, which could be the consequence of removal of mafic root by delamination in the past. The quartz-rich hence mechanically weak crust beneath the Qinling belt could be responsible for the strain focusing and significant reactivation since the Cretaceous. Beneath the central NCC, a 10 km thick high-velocity layer (3.9-4.1 km/s) is observed just above the Moho, consistent with the regional high bulk Vp/Vs ratio (> 1.8). The forward gravity modeling supports the presence of a high-density layer (3.05 g/cm3) at the base of the crust beneath the central NCC. We propose that the high velocity in the lowermost crust beneath the central NCC is most likely due to the repeated mafic underplating, which also results in high crustal Vp/Vs ratio and is responsible for the rapid crustal uplift during the late Mesozoic.

  3. Plasticity in variation of xylem and phloem cell characteristics of Norway spruce under different local conditions

    PubMed Central

    Gričar, Jožica; Prislan, Peter; de Luis, Martin; Gryc, Vladimír; Hacurová, Jana; Vavrčík, Hanuš; Čufar, Katarina

    2015-01-01

    There is limited information on intra-annual plasticity of secondary tissues of tree species growing under different environmental conditions. To increase the knowledge about the plasticity of secondary growth, which allows trees to adapt to specific local climatic regimes, we examined climate–radial growth relationships of Norway spruce [Picea abies (L.) H. Karst.] from three contrasting locations in the temperate climatic zone by analyzing tree-ring widths for the period 1932–2010, and cell characteristics in xylem and phloem increments formed in the years 2009–2011. Variation in the structure of xylem and phloem increments clearly shows that plasticity in seasonal dynamics of cambial cell production and cell differentiation exists on xylem and phloem sides. Anatomical characteristics of xylem and phloem cells are predominantly site-specific characteristics, because they varied among sites but were fairly uniform among years in trees from the same site. Xylem and phloem tissues formed in the first part of the growing season seemed to be more stable in structure, indicating their priority over latewood and late phloem for tree performance. Long-term climate and radial growth analyses revealed that growth was in general less dependent on precipitation than on temperature; however, growth sensitivity to local conditions differed among the sites. Only partial dependence of radial growth of spruce on climatic factors on the selected sites confirms its strategy to adapt the structure of wood and phloem increments to function optimally in local conditions. PMID:26442044

  4. Multi-scale variation in spatial heterogeneity for microbial community structure in an eastern Virginia agricultural field

    NASA Technical Reports Server (NTRS)

    Franklin, Rima B.; Mills, Aaron L.

    2003-01-01

    To better understand the distribution of soil microbial communities at multiple spatial scales, a survey was conducted to examine the spatial organization of community structure in a wheat field in eastern Virginia (USA). Nearly 200 soil samples were collected at a variety of separation distances ranging from 2.5 cm to 11 m. Whole-community DNA was extracted from each sample, and community structure was compared using amplified fragment length polymorphism (AFLP) DNA fingerprinting. Relative similarity was calculated between each pair of samples and compared using geostatistical variogram analysis to study autocorrelation as a function of separation distance. Spatial autocorrelation was found at scales ranging from 30 cm to more than 6 m, depending on the sampling extent considered. In some locations, up to four different correlation length scales were detected. The presence of nested scales of variability suggests that the environmental factors regulating the development of the communities in this soil may operate at different scales. Kriging was used to generate maps of the spatial organization of communities across the plot, and the results demonstrated that bacterial distributions can be highly structured, even within a habitat that appears relatively homogeneous at the plot and field scale. Different subsets of the microbial community were distributed differently across the plot, and this is thought to be due to the variable response of individual populations to spatial heterogeneity associated with soil properties. c2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

  5. Continuity of subsurface fault structure revealed by gravity anomaly: the eastern boundary fault zone of the Niigata plain, central Japan

    NASA Astrophysics Data System (ADS)

    Wada, Shigeki; Sawada, Akihiro; Hiramatsu, Yoshihiro; Matsumoto, Nayuta; Okada, Shinsuke; Tanaka, Toshiyuki; Honda, Ryo

    2017-01-01

    We have investigated gravity anomalies around the Niigata plain, which is a sedimentary basin in central Japan bounded by mountains, to examine the continuity of subsurface fault structures of a large fault zone—the eastern boundary fault zone of the Niigata plain (EBFZNP). The features of the Bouguer anomaly and its first horizontal and vertical derivatives clearly illustrate the EBFZNP. The steep first horizontal derivative and the zero isoline of the vertical derivative are clearly recognized along the entire EBFZNP over an area that shows no surface topographic features of an active fault. Two-dimensional density structure analyses also confirm a relationship between the two first derivatives and the subsurface fault structure. Therefore, we conclude that the length of the EBFZNP as an active fault extends to 56 km, which is longer than previously estimated. This length leads to an estimation of a moment magnitude of 7.4 of an expected earthquake from the EBFZNP.[Figure not available: see fulltext.

  6. Subsurface structure of the eastern edge of the Zagros basin as inferred from gravity and satellite data

    SciTech Connect

    Bushara, M.N.

    1995-09-01

    A data set of 10,505 points of land gravity measurements from southeast Iran obtained from the Bureau Gravimetrique International, combined with Landsat imagery, was used to investigate crustal and Cenozoic lithospheric structure. Interpretation of the Bouguer anomalies reveals three primary structural features. The Zagros Mountain belt is characterized by a progressive decrease in gravity values from -70 mGal near the Persian Gulf to -160 mGal over the structure zone between the Arabian margin and central Iran crustal blocks. The second feature is marked by a backward-L-shaped pair of anomalies that extends from the eastern peripheries of the Zagros basin and wraps around southern Iranian shores. These 15- to 20-km-deep source anomalies, with amplitudes of as much as 10 mGal, are interpreted as intrabasement intrusions demarcating an ancient rift axis. The shallow (6-8)km east-west-trending anomalies are perhaps interbasement uplifts bordered by reverse faults. The third structure, observed on both gravity and Landsat displays, a north-striking eastward-facing topographic escarpment, has a gravity gradient of 0.85 mGal/km, and is right laterally offset approximately 100 km, and is right laterally offset approximately 100 km by the Zagros main recent fault. A comparison of gravity features with surface structures on Thematic Mapper and Landsat Multi-spectral Scanner imagery indicates that a northeast-trending fault system is the result of post-Miocene pervasive transpressive stress coupled with clockwise rotation of underlying basement blocks following the collision of Arabia and Iran. Accommodation structures such as forced folds and {open_quotes}rabbit-ear{close_quotes} anticlines may develop over and on the flanks of the basement blocks, providing remigration and trapping mechanisms for new oil and gas plays.

  7. Impact of forest harvesting on trophic structure of eastern Canadian Boreal Shield lakes: insights from stable isotope analyses.

    PubMed

    Glaz, Patricia; Sirois, Pascal; Archambault, Philippe; Nozais, Christian

    2014-01-01

    Perturbations on ecosystems can have profound immediate effects and can, accordingly, greatly alter the natural community. Land-use such as forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. The objective of this study was to evaluate the impact of forest harvesting on trophic structure in eastern Canadian Boreal Shield lakes. We measured carbon and nitrogen stable isotopes values for aquatic primary producers, terrestrial detritus, benthic macroinvertebrates, zooplankton and brook trout (Salvelinus fontinalis) over a three-year period in eight eastern Boreal Shield lakes. Four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. Stable isotope mixing models showed leaf-litter to be the main food source for benthic primary consumers in both perturbed and unperturbed lakes, suggesting no logging impact on allochthonous subsidies to the littoral food web. Brook trout derived their food mainly from benthic predatory macroinvertebrates in unperturbed lakes. However, in perturbed lakes one year after harvesting, zooplankton appeared to be the main contributor to brook trout diet. This change in brook trout diet was mitigated two years after harvesting. Size-related diet shift were also observed for brook trout, indicating a diet shift related to size. Our study suggests that carbon from terrestrial habitat may be a significant contribution to the food web of oligotrophic Canadian Boreal Shield lakes. Forest harvesting did not have an impact on the diet of benthic primary consumers. On the other hand, brook trout diet composition was affected by logging with greater zooplankton contribution in perturbed lakes, possibly induced by darker-colored environment in these lakes one year after logging.

  8. Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific

    PubMed Central

    Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

    2014-01-01

    Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (FST = 0.08–0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary “graveyards”, serve as sources and recipients of diversity and provide a mechanism for further radiation. PMID:25540693

  9. Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific.

    PubMed

    Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

    2014-11-01

    Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (F ST = 0.08-0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary "graveyards", serve as sources and recipients of diversity and provide a mechanism for further radiation.

  10. A new name for the western spruce budworm (Lepidoptera: Tortricidae)?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There currently is considerable confusion as to the correct application of the name Choristoneura occidentalis. This name has historically been applied to the western spruce budworm, a serious forest pest in western North America. However, Razowski (2008) transferred Archips occidentalis into Choris...

  11. DNA methylome of the 20-gigabase Norway spruce genome

    PubMed Central

    Ausin, Israel; Feng, Suhua; Yu, Chaowei; Liu, Wanlu; Kuo, Hsuan Yu; Jacobsen, Elise L.; Zhai, Jixian; Gallego-Bartolome, Javier; Wang, Lin; Egertsdotter, Ulrika; Street, Nathaniel R.; Jacobsen, Steven E.; Wang, Haifeng

    2016-01-01

    DNA methylation plays important roles in many biological processes, such as silencing of transposable elements, imprinting, and regulating gene expression. Many studies of DNA methylation have shown its essential roles in angiosperms (flowering plants). However, few studies have examined the roles and patterns of DNA methylation in gymnosperms. Here, we present genome-wide high coverage single-base resolution methylation maps of Norway spruce (Picea abies) from both needles and somatic embryogenesis culture cells via whole genome bisulfite sequencing. On average, DNA methylation levels of CG and CHG of Norway spruce were higher than most other plants studied. CHH methylation was found at a relatively low level; however, at least one copy of most of the RNA-directed DNA methylation pathway genes was found in Norway spruce, and CHH methylation was correlated with levels of siRNAs. In comparison with needles, somatic embryogenesis culture cells that are used for clonally propagating spruce trees showed lower levels of CG and CHG methylation but higher level of CHH methylation, suggesting that like in other species, these culture cells show abnormal methylation patterns. PMID:27911846

  12. Wood Anatomy and Insect Defoliator Systems: Is there an anatomical response to sustained feeding by the western spruce budworm (Choristoneura occidentalis) on Douglas-fir (Pseudotusga menziesii)?

    NASA Astrophysics Data System (ADS)

    Axelson, Jodi; Gärtner, Holger; Alfaro, René; Smith, Dan

    2013-04-01

    The western spruce budworm (Choristoneura occidentalis Freeman) is the most widespread and destructive defoliator of coniferous forests in western North America, and has a long-term coexistence with its primary host tree, Douglas-fir (Pseudotsuga menziesii Franco). Western spruce budworm (WSB) outbreaks usually last for several years, and cause reductions in annual growth, stem defects, and regeneration delays. In British Columbia, the WSB is the second most damaging insect after the mountain pine beetle, and sustained and/or severe defoliation can result in the mortality of host trees. Numerous studies have used tree rings to reconstruct WSB outbreaks across long temporal scales, to evaluate losses in stand productivity, and examine isotope ratios. Although some studies have looked at the impacts of artificial defoliation on balsam fir in eastern North America, there has been no prior research on how WSB outbreaks affect the anatomical structure of the stem as described by intra-annual wood density and potential cell size variations. The objective of this study was to anatomically examine the response of Douglas-fir to sustained WSB outbreaks in two regions of southern British Columbia. We hypothesize that the anatomical intra-annual characteristics of the tree rings, such as cell wall thickness, latewood cell size, and/or lumen area changes during sustained WSB outbreaks. To test this hypothesis we sampled four permanent sample plots in coastal and dry interior sites, which had annually resolved defoliation data collected over a 7-12 year period. At each site diameter-at-breast height (cm), height (m), and crown position were recorded and three increment cores were extracted from 25 trees. Increment cores were prepared to permit anatomical and x-ray density analyses. For each tree, a 15µm thick micro section was cut from the radial plane. Digital images of the micro sections were captured and processed. In each annual ring, features such as cell lumen area (µm2

  13. Group velocity dispersion characteristics and one-dimensional regional shear velocity structure of the eastern Indian craton

    NASA Astrophysics Data System (ADS)

    Mandal, Prantik

    2017-02-01

    In the past three years, a semi-permanent network of fifteen 3-component broadband seismographs has become operational in the eastern Indian shield region occupying the Archean (∼2.5-3.6 Ga) Singhbhum-Odisha craton (SOC) and the Proterozoic (∼1.0-2.5 Ga) Chotanagpur Granitic Gneissic terrane (CGGT). The reliable and accurate broadband data for the recent 2015 Nepal earthquake sequence from 10 broadband stations of this network enabled us to estimate the group velocity dispersion characteristics and one-dimensional regional shear velocity structure of the region. First, we measure fundamental mode Rayleigh- and Love-wave group velocity dispersion curves in the period range of 7-70 s and then invert these curves to estimate the crustal and upper mantle structure below the eastern Indian craton (EIC). We observe that group velocities of Rayleigh and Love waves in SOC are relatively high in comparison to those of CGGT. This could be attributed to a relatively mafic-rich crust-mantle structure in SOC resulting from two episodes of magmatism associated with the 1.6 Ga Dalma and ∼117 Ma Rajmahal volcanisms. The best model for the EIC from the present study is found to be a two-layered crust, with a 14-km thick upper-crust (UC) of average shear velocity (Vs) of 3.0 km/s and a 26-km thick lower-crust (LC) of average Vs of 3.6 km/s. The present study detects a sharp drop in Vs (∼-2 to 3%) at 120-260 km depths, underlying the EIC, representing the probable seismic lithosphere-asthenosphere boundary (LAB) at 120 km depth. Such sharp fall in Vs below the LAB indicates a partially molten layer. Further, a geothermal gradient extrapolated from the surface heat flow shows that such a gradient would intercept the wet basalt solidus at 88-103 km depths, suggesting a 88-103 km thick thermal lithosphere below the EIC. This could also signal the presence of small amounts of partial melts. Thus, this 2-3% drop in Vs could be attributed to the presence of partial melts in the

  14. Crustal structure and magnetic lineation along two geo-traverses from western continental margin of India to Eastern Somali Basin, NW Indian Ocean

    NASA Astrophysics Data System (ADS)

    Chaubey, A. K.; Anshu, A.; Sreejith, K.; Pandey, A.

    2012-12-01

    Shipborne gravity and magnetic data along two parallel geo-traverses spanning from western continental margin of India to off Seychelles are used to delineate crustal structure and magnetic pattern of major structural features - western continental margin of India, Laxmi Basin, Laxmi Ridge, Arabian Basin, slow spreading Carlsberg Ridge and Eastern Somali Basin. The seismically constrained gravity models along the geo-traverses suggest considerable variation in crustal thickness - about 38 km on continental shelf of western India to about 4 km of the Eastern Somali Basin. The Eastern Somali Basin is characterized by thin oceanic crustal thickness (~3 to 4 km) as compared to its conjugate Arabian Basin where thickness varies from 5 to 6 km. The magnetic anomalies along the geo-traverse reveal three distinct zones: (i) a zone of relative high frequency short wavelength younger anomalies over the axial parts of the Carlsberg Ridge, (ii) a zone of well developed Early Tertiary magnetic anomalies in both the Arabian and Eastern Somali basins, and (iii) relative magnetic quiet zone, between the above two zones, representing a hiatus in spreading. Based on the results, we present a comparative analysis of crustal configuration and magnetic pattern of major structural features of the study area and discuss its tectonic evolution.

  15. Fracture tolerance of reaction wood (yew and spruce wood in the TR crack propagation system).

    PubMed

    Stanzl-Tschegg, Stefanie E; Keunecke, Daniel; Tschegg, Elmar K

    2011-07-01

    The fracture properties of spruce and yew were studied by in-situ loading in an environmental scanning microscope (ESEM). Loading was performed with a micro-wedge splitting device in the TR-crack propagation direction. The emphasis was laid on investigating the main mechanisms responsible for a fracture tolerant behavior with a focus on the reaction wood. The fracture mechanical results were correlated with the features of the surface structure observed by the ESEM technique, which allows loading and observation in a humid environment. Some important differences between the reaction wood and normal wood were found for both investigated wood species (spruce and yew), including the formation of cracks before loading (ascribed to residual stresses) and the change of fracture mode during crack propagation in the reaction wood. The higher crack propagation resistance was attributed mainly to the different cell (i.e. fiber) geometries (shape, cell wall thickness) and fiber angle to the load axis of the reaction wood, as basic structural features are responsible for more pronounced crack deflection and branching, thus leading to crack growth retardation. Fiber bridging was recognized as another crack growth retarding mechanism, which is effective in both wood species and especially pronounced in yew wood.

  16. Lithospheric Structure in Eastern Africa and the Arabian Plate from Joint Inversion of Surface Wave Dispersion Data and Receiver Functions

    NASA Astrophysics Data System (ADS)

    Dugda, M. T.; Nyblade, A. A.; Rodgers, A.; Al-Amri, A.; Julia, J.

    2006-12-01

    Lithospheric structure beneath Eastern Africa (Ethiopia, Kenya, and Djibouti) and the Arabian Shield and Platform has been investigated using a joint inversion of receiver functions and surface wave dispersion measurements from 10 to 175 s. Our models help to constrain the extent of modification made to the lithosphere in the region by hotspot tectonism. Most of the data for this study come from three major sources: the Ethiopia and Kenya Broadband Seismic Experiments which were carried out between 2000-2002 and 2001-2002, respectively, and data from the Saudi Arabia National Digital Seismic Network (KACST). We find that there is little or no seismic lid under the Main Ethiopian Rift and Afar. The results for the Ethiopian Plateau show that there has been thinning of the lithosphere by about ~30 40 km from typical Mozambique Belt lithosphere under Tanzania, which was reported to be up to 120 km thick, and that there has been a reduction in maximum shear wave velocity of the lid by about 7%. Replacement of the bottom of the former Mozambique Belt lithosphere by warm plume material with a partial erosion of the lithosphere can explain both the thinning of the lithosphere and the reduction of maximum velocity. Preliminary results suggest similar lithospheric structure beneath the Arabian Shield. The results from Kenya are similar to that of the results for the Mozambique Belt Lithosphere in Tanzania, showing 100-120 km thick lithosphere.

  17. Changes in soil microbial community structure following the abandonment of agricultural terraces in mountainous areas of Eastern Spain

    PubMed Central

    Zornoza, R.; Guerrero, C.; Mataix-Solera, J.; Scow, K.M.; Arcenegui, V.; Mataix-Beneyto, J.

    2012-01-01

    In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicular-arbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils. PMID:22291451

  18. The influence of habitat structure on genetic differentiation in red fox populations in north-eastern Poland.

    PubMed

    Mullins, Jacinta; McDevitt, Allan D; Kowalczyk, Rafał; Ruczyńska, Iwona; Górny, Marcin; Wójcik, Jan M

    2014-01-01

    The red fox (Vulpes vulpes) has the widest global distribution among terrestrial carnivore species, occupying most of the Northern Hemisphere in its native range. Because it carries diseases that can be transmitted to humans and domestic animals, it is important to gather information about their movements and dispersal in their natural habitat but it is difficult to do so at a broad scale with trapping and telemetry. In this study, we have described the genetic diversity and structure of red fox populations in six areas of north-eastern Poland, based on samples collected from 2002-2003. We tested 22 microsatellite loci isolated from the dog and the red fox genome to select a panel of nine polymorphic loci suitable for this study. Genetic differentiation between the six studied populations was low to moderate and analysis in Structure revealed a panmictic population in the region. Spatial autocorrelation among all individuals showed a pattern of decreasing relatedness with increasing distance and this was not significantly negative until 93 km, indicating a pattern of isolation-by-distance over a large area. However, there was no correlation between genetic distance and either Euclidean distance or least-cost path distance at the population level. There was a significant relationship between genetic distance and the proportion of large forests and water along the Euclidean distances. These types of habitats may influence dispersal paths taken by red foxes, which is useful information in terms of wildlife disease management.

  19. Changes in soil microbial community structure following the abandonment of agricultural terraces in mountainous areas of Eastern Spain.

    PubMed

    Zornoza, R; Guerrero, C; Mataix-Solera, J; Scow, K M; Arcenegui, V; Mataix-Beneyto, J

    2009-07-01

    In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicular-arbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils.

  20. Variation of Crustal Shear Velocity Structure Along the Eastern Lau Back-Arc Spreading Center Constrained By Seafloor Compliance

    NASA Astrophysics Data System (ADS)

    Zha, Y.; Webb, S. C.; Dunn, R. A.

    2014-12-01

    Measurements of seafloor compliance, the deformation under long period (typically 30-300 s) ocean wave forcing, are primarily sensitive to crustal shear velocity structure. We analyze seafloor compliance from data collected from a subset of 50 broadband Ocean Bottom Seismographs (OBS) deployed at the Eastern Lau spreading center (ELSC) from 2009 to 2010. The ELSC is a 400-km-long back-arc spreading center lying closely to the Tonga subduction trench in the southwestern Pacific. Seafloor morphology, crustal seismic structure and lava composition data show rapid variations along the ridge as the ridge migrates away from the volcanic arc front to the north, indicating a decreasing influence of the subducting slab. We calculate seafloor compliance functions by taking the spectral transfer function between the vertical displacement and pressure signal recorded by the 4-component OBSs, which are equipped with differential pressure gauges (DPGs). In the ridge perpendicular direction, compliance amplitude vary by more than an order of magnitude from the ridge crest to older seafloor covered by sediment. Along the spreading ridge, compliance measured from on-axis sites increases southwards, indicative of a decrease in the upper crustal shear velocity possibly due to increasing porosity and a thickening extrusive layer [Jacobs et al., 2007; Dunn et al., 2013]. We apply a Markov Chain Monte Carlo method to invert the compliance functions for crustal shear velocities at various locations along the ELSC.

  1. Daily precipitation and tropical moisture exports across the eastern United States: an application of archetypal analysis to identify spatiotemporal structure

    NASA Astrophysics Data System (ADS)

    Steinschneider, S.; Lall, U.

    2015-12-01

    This study examines the spatiotemporal variability of two sets of daily precipitation from the ERA-Interim reanalysis across the eastern United States between 1979-2013: 1) total precipitation, and 2) precipitation originating from tropical moisture exports (TMEs), which have been linked to extremes of midlatitude precipitation. We introduce archetypal analysis (AA) as a new method to decompose and characterize structures within the spatiotemporal climate data. AA is uniquely suited to identify extremal patterns and is a complementary method to Empirical Orthogonal Function (EOF) analysis. We provide a brief comparison between AA and EOF analysis and then examine the spatiotemporal variability, circulation anomalies, and sea surface temperature teleconnections associated with the archetypes of the two precipitation variables. Markovian structure, seasonal variability, and inter-annual trends in archetype occurrence are explored using nonparametric generalized linear models (GLMs). Results show that the modes of precipitation variability and their associated teleconnections are very similar between total and TME precipitation, suggesting that TMEs can help explain prevailing modes of total precipitation variability. Both total and TME precipitation shift longitudinally conditional on the phase of the Pacific Decadal Oscillation (PDO) and sea surface temperatures in the North Atlantic, and they are inhibited during strong, negative PDO and positive Atlantic Multidecadal Oscillation (AMO) regimes. The GLM analysis reveals distinct seasonal cycles and decadal trends in archetypes likely associated with the strength and position of the North Atlantic Subtropical High (NASH).

  2. Cloudwater and ozone effects upon high elevation red spruce: A summary of study results from Whitetop Mountain, Virginia

    SciTech Connect

    Thornton, F.C.; Joslin, J.D.; Pier, P.A.

    1994-11-01

    This paper integrates the results of a number of studies on the effects of cloudwater and ozone (O{sub 3}) on red spruce (Picea rubens Sarg.) seedlings, saplings, and mature trees at Whitetop Mountain, VA, over a 3-yr period. These investigations consisted of (1) seedling chamber exclusion studies, (2) mature tree branch chamber exclusion studies, and (3) field experiments comparing responses of seedlings, saplings, and mature trees. The studies included treatments that : (1) excluded clouds and O{sub 3} (COE), (2) excluded clouds and had ambient O{sub 3} (CE), and (3) exposed plants to both clouds and O{sub 3} either with (CC) or without (AA) chambers. Seedlings and mature branches in the various treatments were compared with respect to growth rates, gas exchange rates, foliar nutrition, and chlorophyll and wax content. Soil solution, throughfall, and foliar responses of mature trees near the summit, receiving differing amounts of cloud exposure (low cloud and high cloud sites) were also monitored. Ozone was found to have minimal effects on the parameters measured, whereas cloudwater exposure was found to have adverse effects on several response parameters. Chambered seedlings that were exposed to cloudwater (AA and CC), and mature trees at the high cloud site had significantly lower foliar Ca and Mg concentrations than their counterparts, which were protected from exposure (seedlings) or received low cloud exposure (mature). A 3 to 5{degrees}C increase in cold tolerance was also measured in seedlings form which cloudwater was excluded. These findings suggest that cloudwater-mediated effects are currently having a negative impact on the health of red spruce, and may be involved in red spruce decline in the eastern USA. 62 refs., 2 figs., 5 tabs.

  3. Structure and present-day compression in the offshore area between Alicante and Ibiza Island (Eastern Iberian Margin)

    NASA Astrophysics Data System (ADS)

    Maillard, Agnès; Mauffret, Alain

    2013-04-01

    This study deals with the structure and recent deformation of the Eastern Iberian margin, extending from basement to seafloor and including the south-western margin of the Valencia Basin, the Alicante Shelf, the Ibiza Channel and its southern margin descending into the Algerian Basin. This area underwent a complex tectonic evolution linked to the back-arc opening of the North-western Mediterranean and the concomitant contraction of the Betic belt due to the collision with blocks located between Africa and Europe. This Oligo-Miocene structural heritage gave rise to a complex and continuous deformation through times including Late Miocene post-orogenic extension and Pliocene to Quaternary compression in the western Balearic area and coeval extension in the Valencia basin. This study presents maps of the depth to basement and Base of the Pliocene, as well as bathymetry data and seismic lines, which provide a precise integrated 3D study of the offshore domain. It reveals a major reactivation of the area, represented by the N80 to N60 trending structures, small discontinuous folds and thrusts in the Ibiza Channel and a large flexure on the Alicante shelf. The structures are picked out by erosion surfaces or deposits linked to the Messinian Salinity Crisis (MSC). These markers are ubiquitous in the seismic sedimentary sequences and record the lateral and vertical deformation active from the Messinian Salinity Crisis to the Present. The contraction in the western Iberian margin and concomitant extension in the southern Valencia Basin are consistent with the regional stress field as determined from the focal mechanisms of offshore earthquakes or recent GPS measurements. The tectonic compression of the studied area casts doubt on the eventual propagation of the present-day compressive stress from the Algerian margin to the Western Balearic Promontory.

  4. Transverse zones controlling the structural evolution of the Zipaquira Anticline (Eastern Cordillera, Colombia): Regional implications

    NASA Astrophysics Data System (ADS)

    García, Helbert; Jiménez, Giovanny

    2016-08-01

    We report paleomagnetic, magnetic fabric and structural results from 21 sites collected in Cretaceous marine mudstones and Paleogene continental sandstones from the limbs, hinge and transverse zones of the Zipaquira Anticline (ZA). The ZA is an asymmetrical fold with one limb completely overturned by processes like gravity and salt tectonics, and marked by several axis curvatures. The ZA is controlled by at least two (2) transverse zones known as the Neusa and Zipaquira Transverse Zones (NTZ and ZTZ, respectively). Magnetic mineralogy methods were applied at different sites and the main carriers of the magnetic properties are paramagnetic components with some sites being controlled by hematite and magnetite. Magnetic fabric analysis shows rigid-body rotation for the back-limb in the ZA, while the forelimb is subjected to internal deformation. Structural and paleomagnetic data shows the influence of the NTZ and ZTZ in the evolution of the different structures like the ZA and the Zipaquira, Carupa, Rio Guandoque, Las Margaritas and Neusa faults, controlling several factors as vergence, extension, fold axis curvature and stratigraphic detatchment. Clockwise rotations unraveled a block segmentation following a discontinuos model caused by transverse zones and one site reported a counter clockwise rotation associated with a left-lateral strike slip component for transverse faults (e.g. the Neusa Fault). We propose that diverse transverse zones have been active since Paleogene times, playing an important role in the tectonic evolution of the Cundinamarca sub-basin and controlling the structural evolution of folds and faults with block segmentation and rotations.

  5. An unusual triangle structure associated with thrust front development in the thin-skinned Eastern Jura Mountains

    NASA Astrophysics Data System (ADS)

    Malz, Alexander; Madritsch, Herfried; Meier, Beat; Heuberger, Stefan; Kley, Jonas

    2014-05-01

    The Late Miocene to Early Pliocene Jura fold-and-thrust belt, stretching across northern Switzerland and eastern France, is a classical example of a thin-skinned foreland fold-and-thrust belt, its basal décollement being located in Mid- to Upper Triassic evaporites. The arcuate mountain range referred to as the Folded Jura is formed by mainly N-vergent thrusts and associated folds. In our study area, comprising the easternmost part of the thrust belt, the border between the Folded Jura and the non-detached autochthonous foreland (Tabular Jura) is not clearly defined. In most interpretations, the frontal thrust is taken to coincide with the northernmost anticline of the Folded Jura visible at the surface. Newly reprocessed, depth-migrated reflection seismic sections allow us to closer analyse the regional structural framework of the thrust front. Constant line-length and area cross section balancing techniques are applied to verify geometry of the interpreted structures. The best matching interpretation of the thin-skinned thrust belt front is a complex triangle structure, which traces an offset of the basal décollement by an inherited pre-exisiting normal fault that was previously associated with the border fault of a Late Paleozoic trough. This "unusual" triangle structure is defined by a number of (at least two) thrusts and backthrusts above each other associated with several secondary faults. The most characteristic feature of the fault zone is its low width with respect to the stratigraphic thickness influenced by the fault. The triangle structure shows a very uniform amount of shortening over much of its length. We interpret this uniform shortening to suggest that the configuration of the structure represents a maximum attainable, "saturated" amount of deformation achieved during an initial phase of Jura folding. To the west of our study area the triangle structure merges with the northernmost Jura anticline, which shows a conspicuous change in strike from

  6. 3D P-wave Velocity Structure Beneath the Eastern Canadian Shield and Northern Appalachian Region

    NASA Astrophysics Data System (ADS)

    Villemaire, M.; Darbyshire, F. A.; Bastow, I. D.

    2010-12-01

    Previous seismic studies of the upper mantle of the Canadian Shield have indicated some low-velocity anomalies within the cratonic lithosphere in the Abitibi-Grenville region. The lack of seismograph station coverage to the east and south-east of the studied area prevented definition of the 3D geometry of these anomalies. Adding new stations from the province of Quebec and from the northeastern United States allows us to carry out new studies of the P-wave velocity structure of the upper mantle, in order to better understand the complexity of the region and the interaction of the lithosphere with possible thermal anomalies in the underlying mantle. We analysed teleseismic P wave arrivals from almost 200 earthquakes, recorded at 45 stations deployed across the provinces of Quebec and Ontario and across the northeastern US. The relative arrival times of teleseismic P waves across the array were measured using the cross-correlation method of VanDecar & Crosson (1990). The travel time data were then inverted to estimate the 3D P-wave velocity structure beneath the region, using the least-squares tomographic inversion code of VanDecar (1991). The model shows some interesting features. We see a diffuse low-velocity structure beneath New-England that extends to at least 500 km depth, and that may be related to the Appalachian Mountain belt. There is also a linear low-velocity structure, flanked by higher velocities, perpendicular to the Grenville Front, and along the Ottawa Valley. We interpret this feature as a mantle signature of the Great Meteor Hotspot track. We have looked for systematic differences between the mantle underlying the Archean Superior craton and the Proterozoic Grenville Province but did not find a significant difference in the upper mantle. We investigate the role of thermal and compositional effects to interpret the velocity models and to relate the patterns of the anomalies to past and present tectonic structures.

  7. Structure and dynamics in the north Jizhong Depression, Bohai Bay Basin, Eastern China

    NASA Astrophysics Data System (ADS)

    Miao, Q.; Qi, J.; Zhang, J.

    2015-12-01

    Study of structural geology in the north Jizhong Depression, Bohai Bay has achieved great breakthroughs in recent years. However the studies of structure and dynamics still remain much controversy. Based on the 3D and partial 2D seismic data, combined with regional geology and well data, the characteristics of structures in the north Jizhong Deprssion are analyzed, the dynamics is discussed. Our analyses show that the Cenozoic structures in the north Jizhong Depression can be subdivided into extensional system and strike-slip system. Extensional system concludes series of normal faults and transfer faults. Normal faults are mainly trend NNE and NE. They control the Paleogene sediments in sub-depressions of hanging-wall, and bottom out into a sub-horizontal detachment zone in deep level shaped like listric. Transfer faults mainly adjust displacement of normal faults, yet some like Tongbozhen and Niutuozhen are transfer faults in Paleocene and Eocene but change to normal faults in Oligocene. Strike-slip system is predominantly consisted by sub-vertical right-lateral strike-slip faults such as Xin`anzhen and Maxi. From seismic profiles, Xin`anzhen and Maxi cut into basement but only influence the sediments of Ed of Paleogene and Lower Neogene. Based on the relation of sedimentary sequence and faults, the extensional system mainly develops from Paleocene to Late Oligocene, but strike-slip system predominantly develops from Late Oligocene to Miocene. From the superposed section of crustal structure and basin structure in Jizhong Depression, the Cenozoic sub-basin is just located on the thinner zones of crustal, corresponding with the location of mantle uplift. It indicates that the Paleogene development of Jizhong Depression is related to the horizontal tension caused by uplift of magma in mantle. The results illustrate that extensional deformation in Jizhong depression is caused by the uplift of magma. The right-lateral strike-slip deformation, same with Tancheng

  8. Effects of structural complexity enhancement on eastern red-backed salamander (Plethodon cinereus) populations in northern hardwood forests

    USGS Publications Warehouse

    McKenny, H.C.; Keeton, W.S.; Donovan, T.M.

    2006-01-01

    Managing for stand structural complexity in northern hardwood forests has been proposed as a method for promoting microhabitat characteristics important to eastern red-backed salamanders (Plethodon cinereus). We evaluated the effects of alternate, structure-based silvicultural systems on red-backed salamander populations at two research sites in northwestern Vermont. Treatments included two uneven-aged approaches (single-tree selection and group-selection) and one unconventional approach, termed "structural complexity enhancement" (SCE), that promotes development of late-successional structure, including elevated levels of coarse woody debris (CWD). Treatments were applied to 2 ha units and were replicated two to four times depending on treatment. We surveyed red-backed salamanders with a natural cover search method of transects nested within vegetation plots 1 year after logging. Abundance estimates corrected for detection probability were calculated from survey data with a binomial mixture model. Abundance estimates differed between study areas and were influenced by forest structural characteristics. Model selection was conducted using Akaike Information Criteria, corrected for over-dispersed data and small sample size (QAICc). We found no difference in abundance as a response to treatment as a whole, suggesting that all of the uneven-aged silvicultural systems evaluated can maintain salamander populations after harvest. However, abundance was tied to specific structural habitat attributes associated with study plots within treatments. The most parsimonious model of habitat covariates included site, relative density of overstory trees, and density of more-decayed and less-decayed downed CWD. Abundance responded positively to the density of downed, well-decayed CWD and negatively to the density of poorly decayed CWD and to overstory relative density. CWD volume was not a strong predictor of salamander abundance. We conclude that structural complexity enhancement

  9. Cenozoic structural history of selected areas in the eastern Great Basin, Nevada-Utah

    USGS Publications Warehouse

    Anderson, R. Ernest

    1983-01-01

    The Confusion Range structural trough (CRST) of west-central Utah predates the Oligocene rocks that are exposed along it. The northern part of the axial region of the CRST is complicated by structures that include reverse faults and associated folds, a large-amplitude mushroom fold, and belts of sharply flexed to overturned strata some of which are fault bounded. These structures, which also predate the Oligocene rocks, formed in a compressional regime that has been interpreted as resulting from thin-skinned gravitational gliding toward the axis of the CRST. Study of the sparse Tertiary rocks that are scattered along the axial region of the CRST reveals abundant evidence of Oligocene and younger deformation. The chief evidence includes (1) widespread Oligocene and Miocene coarse clastic rocks, many of which are conglomerates, that attest to local and distant tectonism, (2) faults that range from high-angle structures generally with less than 100 m of normal displacement to low-angle attenuation faults some of which may have large displacements, and (3) open asymmetric folds. Together with the distribution of sheet-form bodies of ash-flow tuffs, the Oligocene stratigraphic record allows for paleogeographic reconstruction of a lacustrine basin across what is now the northern Confusion Range and one or more basins in the southern part of the CRST. The basins are inferred to have been fault controlled by reactivation of previously formed faults or steep fold flanks. They may have been localized by differential vertical movements similar to those that produced the older systems of folds and faults. Parts of early formed basins were cannibalized as local syndepositional deformation took place in the axial region of the CRST. Both limbs of the CRST have been modified by folds that involve Oligocene rocks. Some of these folds appear to be genetically related to displacements on faults that bound them. They may record thin-skinned Neogene tectonic displacements toward the

  10. A terminal Pleistocene child cremation and residential structure from eastern Beringia.

    PubMed

    Potter, Ben A; Irish, Joel D; Reuther, Joshua D; Gelvin-Reymiller, Carol; Holliday, Vance T

    2011-02-25

    The dearth of human remains and residential sites has constrained inquiry into Beringian lifeways at the transition of the late Pleistocene-early Holocene. We report on human skeletal remains and a residential structure from central Alaska dated to ~11,500 calendar years ago. The remains are from a ~3-year-old child who was cremated in a pit within a semisubterranean house. The burial-cremation and house have exceptional integrity and preservation and exhibit similarities and differences to both Siberian Upper Paleolithic and North American Paleoindian features.

  11. Impacts of logging and wildfire on an upland black spruce community in northwestern Ontario.

    PubMed

    Johnston, M H; Elliott, J A

    1996-01-01

    Plant species composition and community structure were compared among four sites in an upland black spruce community in northwestern Ontario. One site had remained undisturbed since the 1930s and three had been disturbed by either logging, fire, or both logging and fire. Canonical correspondence ordination analyses indicated that herbaceous species composition and abundance differed among the disturbance types while differences in the shrub and tree strata were less pronounced. In the herb stratum Pleurozium schreberi, Ptilium crista-castrensis and Dicranum polysetum were in greatest abundance on the undisturbed forest site, while the wildfire and burned cutover sites were dominated by Epilobium angustifolium and Polytrichum juniperinum. The unburned harvested site was dominated by Epilobium angustifolium, Cornus canadensis and Pleurozium schreberi. Species richness was lower on the undisturbed site than on any of the disturbed sites while species diversity (H') and evenness (Hill's E5) were higher on the unburned harvested site than on the other sites. Results suggest that herb re-establishment is different among harvested and burned sites in upland black spruce communities and we hypothesize that differences in the characteristics of the disturbance were responsible, in particular, the impact of burning on nutrient availability. These differences need to be taken into account in determining the effects of these disturbances on biodiversity and long-term ecosystem management.

  12. Higher fine-scale genetic structure in peripheral than in core populations of a long-lived and mixed-mating conifer - eastern white cedar (Thuja occidentalis L.)

    PubMed Central

    2012-01-01

    Background Fine-scale or spatial genetic structure (SGS) is one of the key genetic characteristics of plant populations. Several evolutionary and ecological processes and population characteristics influence the level of SGS within plant populations. Higher fine-scale genetic structure may be expected in peripheral than core populations of long-lived forest trees, owing to the differences in the magnitude of operating evolutionary and ecological forces such as gene flow, genetic drift, effective population size and founder effects. We addressed this question using eastern white cedar (Thuja occidentalis) as a model species for declining to endangered long-lived tree species with mixed-mating system. Results We determined the SGS in two core and two peripheral populations of eastern white cedar from its Maritime Canadian eastern range using six nuclear microsatellite DNA markers. Significant SGS ranging from 15 m to 75 m distance classes was observed in the four studied populations. An analysis of combined four populations revealed significant positive SGS up to the 45 m distance class. The mean positive significant SGS observed in the peripheral populations was up to six times (up to 90 m) of that observed in the core populations (15 m). Spatial autocorrelation coefficients and correlograms of single and sub-sets of populations were statistically significant. The extent of within-population SGS was significantly negatively correlated with all genetic diversity parameters. Significant heterogeneity of within-population SGS was observed for 0-15 m and 61-90 m between core and peripheral populations. Average Sp, and gene flow distances were higher in peripheral (Sp = 0.023, σg = 135 m) than in core (Sp = 0.014, σg = 109 m) populations. However, the mean neighborhood size was higher in the core (Nb = 82) than in the peripheral (Nb = 48) populations. Conclusion Eastern white cedar populations have significant fine-scale genetic structure at short distances. Peripheral

  13. Vertical structure of aerosols, temperature, and moisture associated with an intense African dust event observed over the eastern Caribbean

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce; Prospero, Joseph M.; Jonsson, Haflidi H.; Kreidenweis, Sonia M.

    2013-05-01

    unusually intense African dust event affected a large area of the western Atlantic and eastern Caribbean in early April 2010. Measurements made east of Barbados from the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter research aircraft are used to characterize particle size distributions; vertical distributions of aerosols, temperature, and moisture; and processes leading to the observed stratification in the boundary layer. The vertical profiles of various aerosol characterizations were similar on both days and show three layers with distinct aerosol and thermodynamic characteristics: the Saharan Air Layer (SAL; ~2.2 km ± 500 m), a subcloud layer (SCL; surface to ~500 m), and an intermediate layer extending between them. The SAL and SCL display well-mixed aerosol and thermodynamic characteristics; but the most significant horizontal and vertical variations in aerosols and thermodynamics occur in the intermediate layer. The aerosol variability observed in the intermediate layer is likely associated with modification by shallow cumulus convection occurring sometime in the prior history of the air mass as it is advected across the Atlantic. A comparison of the thermodynamic structure observed in the event from its origin over Africa with that when it reached Barbados indicates that the lower part of the SAL was moistened by surface fluxes as the air mass was advected across the Atlantic. Mixing diagrams using aerosol concentrations and water vapor mixing ratios as conserved parameters provide insight into the vertical transports and mixing processes that may explain the observed aerosol and thermodynamic variability in each layer.

  14. The spatial structure of epidemic emergence: geographical aspects of poliomyelitis in north-eastern USA, July–October 1916

    PubMed Central

    Trevelyan, Barry; Cliff, Andrew D.

    2005-01-01

    Summary The great epidemic of poliomyelitis which swept New York City and surrounding territory in the summer of 1916 eclipsed all previous global experience of the disease. We draw on epidemiological information that is included in the seminal US Public Health Bulletin 91, ‘Epidemiologic studies of poliomyelitis in New York City and the northeastern United States during the year 1916’ (Washington DC, 1918), to re-examine the spatial structure of the epidemic. For the main phase of transmission of the epidemic, July–October 1916, it is shown that the maximum concentration of activity of poliomyelitis occurred within a 128-km radius of New York City. Although the integrity of the poliomyelitis cluster was maintained up to approximately 500 km from the metropolitan focus, the level and rate of propagation of disease declined with distance from the origin of the epidemic. Finally, it is shown that the geographical transmission of the epidemic in north-eastern USA probably followed a process of mixed contagious–hierarchical diffusion. PMID:16741560

  15. Magnetic Anomaly Modeling of Volcanic Structure and Stratigraphy - Socorro Island, Eastern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Urrutia-Fucugauchi, Jaime; Escorza-Reyes, Marisol; Pavon-Moreno, Julio; Perez-Cruz, Ligia; Sanchez-Zamora, Osvaldo

    2013-04-01

    Results of a magnetic survey of the volcanic structure of Socorro Island in the Revillagigedo Archipielago are presented. Socorro is part of a group of seamounts and oceanic islands built by volcanic activity at the northern end of the Mathematician ridge and intersection with the Clarion and Rivera fracture zones. Subaerial volcanic activity is characterized by alkaline and peralkaline compositions, marked by pre-, syn- and post-caldera phases of the Evermann volcano, and the Holocene mafic activity of the Lomas Coloradas. The magnetic survey conducted in the central-southern sector of the island permits to investigate the volcanic structure and subsurface stratigraphy. Regional fields for second- and third-degree polynomials show a magnetic low over the caldera, positive anomalies above the pre-caldera deposits and intermediate amplitude anomalies over Lomas Coloradas. Residual fields delineate the structural rim of the caldera, anomaly trends for the pre- and post-caldera deposits and a broad anomaly over Lomas Coloradas. Regional-residual anomalies, first vertical derivative, analytical upward and downward continuations, and forward four-layer modeling are used to construct the geophysical models. Rock magnetic properties were analyzed on samples collected at 24 different sites. Magnetic susceptibility showed wide range of variation from ~10 to ~500 10-3 SI, corresponding to the different lithologies from trachytes and glass-rich tuffs to alkali basalts. Data have been divided into groups with low, intermediate and high values. Rock magnetic analyses indicate that magnetite and titanomagnetites are the main magnetization carriers. Magnetic hysteresis loops indicate low coercivity minerals, with high saturation and remanent magnetizations and PSD domain states. Magnetic susceptibility versus temperature curves show irreversible behavior with Curie temperatures around 560-575 C, suggesting magnetite and Ti-poor titanomagnetites. Paleomagnetic directions

  16. ERTS-1 imagery of eastern Africa: A first look at the geological structure of selected areas

    NASA Technical Reports Server (NTRS)

    Mohr, P. A. (Principal Investigator)

    1972-01-01

    The author has identified the following significant results. Imagery of the African rift system resolves the major Cainozoic faults, zones of warping, and associated volcanism. It also clearly depicts the crystal grain of the Precambrian rocks where these are exposed. New structural features, or new properties of known features such as greater extent, continuity, and linearity are revealed by ERTS-1 imagery. This applies, for example, to the NE-SW fracture zones in Yemen, the Aswa mylonite zone at the northern end of the Western Rift, the Nandi fault of western Kenya, the linear faults of the Elgeyo escarpment in the Gregory Rift, and the hemibasins of warped Tertiary lavas on the Red Sea margin of Yemen, matching those of Ethiopian plateau-Afar margin. A tentative scheme is proposed, relating the effect on the pattern of Cainozoic faulting of the degree of obliquity to Precambrian structural trend. It is particularly noteworthy that, even where the Precambrian grain determines the rift faulting to be markedly oblique to the overall trend of the rift trough, for example, in central Lake Tanganyika, the width of the trough is not significantly increased. Some ground mapped lithological boundaries are obscure on ERTS-1 imagery.

  17. Structure of the eastern Seattle fault zone, Washington state: New insights from seismic reflection data

    USGS Publications Warehouse

    Liberty, L.M.; Pratt, T.L.

    2008-01-01

    We identify and characterize the active Seattle fault zone (SFZ) east of Lake Washington with newly acquired seismic reflection data. Our results focus on structures observed in the upper 1 km below the cities of Bellevue, Sammamish, Newcastle, and Fall City, Washington. The SFZ appears as a broad zone of faulting and folding at the southern boundary of the Seattle basin and north edge of the Seattle uplift. We interpret the Seattle fault as a thrust fault that accommodates north-south shortening by forming a fault-propagation fold with a forelimb breakthrough. The blind tip of the main fault forms a synclinal growth fold (deformation front) that extends at least 8 km east of Vasa Park (west side of Lake Sammamish) and defines the south edge of the Seattle basin. South of the deformation front is the forelimb break-through fault, which was exposed in a trench at Vasa Park. The Newcastle Hills anticline, a broad anticline forming the north part of the Seattle uplift east of Lake Washington, is interpreted to lie between the main blind strand of the Seattle fault and a backthrust. Our profiles, on the northern limb of this anticline, consistently image north-dipping strata. A structural model for the SFZ east of Lake Washington is consistent with about 8 km of slip on the upper part of the Seattle fault, but the amount of motion is only loosely constrained.

  18. Nesting ecology of boreal forest birds following a massive outbreak of spruce beetles

    USGS Publications Warehouse

    Matsuoka, S.M.; Handel, C.M.

    2007-01-01

    We studied breeding dark-eyed juncos (Junco hyemalis), yellow-rumped warblers (Dendroica coronata), and spruce-nesting birds from 1997 to 1998 among forests with different levels of spruce (Picea spp.) mortality following an outbreak of spruce beetles (Dendroctonus rufipennis) in Alaska, USA. We identified species using live and beetle-killed spruce for nest sites and monitored nests to determine how the outbreak influenced avian habitat selection and reproduction. We tested predictions that 1) nesting success of ground-nesting juncos would increase with spruce mortality due to proliferation of understory vegetation available to conceal nests from predators, 2) nesting success of canopy-nesting warblers would decrease with spruce mortality due to fewer live spruce in which to conceal nests, and 3) both species would alter nest-site selection in response to disturbance. Juncos did not benefit from changes in understory vegetation; nesting success in highly disturbed stands (46%) was comparable to that in undisturbed habitats throughout their range. In stands with low spruce mortality, nesting success of juncos was low (5%) and corresponded with high densities of red squirrels (Tamiasciurus hudsonicus). Yellow-rumped warblers nested exclusively in spruce, but success did not vary with spruce mortality. As disturbance increased, nesting warblers switched from selecting forest patches with high densities of live white spruce (Picea glauca) to patches with beetle-killed spruce. Warblers also placed nests in large-diameter live or beetle-killed spruce, depending on which was more abundant in the stand, with no differences in nesting success. Five of the 12 other species of spruce-nesting birds also used beetle-killed spruce as nest sites. Because beetle-killed spruce can remain standing for >50 years, even highly disturbed stands provide an important breeding resource for boreal forest birds. We recommend that boreal forest managers preserve uncut blocks of infested

  19. Neogene Structural History of Biak and the Biak Basin, Eastern Indonesia

    NASA Astrophysics Data System (ADS)

    Gold, D.; Hall, R.; Burgess, P.

    2014-12-01

    The Biak Basin is within a frontier region, located between the islands of Biak to the north and Yapen to the south in the Indonesian province of West Papua. The Biak Basin is underlain by a Paleogene basement sequence that originated in an intra-oceanic island arc, formed on the leading edge of the oceanic Pacific-Caroline Plate. The basin has a structural history that can be divided into three stages: 1) a compressional stage, 2) a rifting stage and 3) a strike-slip stage. The compressional stage occurred during the Early Miocene. Collision of the arc with the northern edge of the Australian continental margin caused folding and thrusting of the basement sequence which was uplifted and subaerially exposed resulting in a widespread unconformity that can be traced west through the western Bird's Head as far as Halmahera. Following this collision the Biak Basin was filled largely by carbonates from the Early Miocene. During the Middle-Late Miocene the Biak Basin underwent a period of rapid subsidence resulting from a period of rifting. Extension occurred as convergence of the Pacific Plate with the Australian margin produced a regional stress field in which the maximum compressive stress was orientated NE-SW and maximum tensional stress NW-SE. This tensional stress produced NE-SW striking horsts and grabens with a Paleogene basement overlain by Lower Miocene carbonates. A final stage involving strike-slip faulting occurred during the Pliocene-Pleistocene with the initiation of major regional faults such as those of the Yapen Fault Zone and Biak Array which bound the southern and northeastern margins of the basin respectively. The strike-slip faulting accommodated continued convergence between the Pacific and Australian plates and uplifted Miocene carbonates as pop-up structures now observed on Biak.There are parallels to the Biak Basin in basins within the Basin and Range Province of the western United States, in particular the Walker Lake Basin, Nevada and other

  20. The structure of phytoplankton communities in the eastern part of the Laptev Sea

    NASA Astrophysics Data System (ADS)

    Sukhanova, I. N.; Flint, M. V.; Georgieva, E. Ju.; Lange, E. K.; Kravchishina, M. D.; Demidov, A. B.; Nedospasov, A. A.; Polukhin, A. A.

    2017-01-01

    Studies have been performed on a transect along 130°30' E from the Lena River delta (71°60' N) to the continental slope and adjacent deepwater area (78°22' N) of the Laptev Sea in September 2015. The structure of phytoplankton communities has distinct latitudinal zoning. The southern part of the shelf (southward of 73°10' N), the most desalinated by riverine discharge, houses a phytoplankton community with a biomass of 175-840 mg/m2, domination of freshwater Aulacoseira diatoms, and significant contribution of green algae (both in abundance and biomass). The northern border for the distribution range of the southern complex of phytoplankton species lies between the 8 and 18 psu isohalines ( 73°10' N). The continental slope and deepwater areas of the Laptev Sea (north of 77°30' N), with a salinity of >27 psu in the upper mixed layer, are populated by the community prevalently composed of Chaetoceros and Rhizosolenia diatoms, very abundant in the Arctic, and dinoflagellates. The phytoplankton number in this area fall in the range of 430-1100 × 106 cell/m2, and the biomass, in the range of 3600 mg/m2. A moderate desalinating impact of the Lena River discharge is observed in the outer shelf area between 73°20' and 77°30' N; the salinity in the upper mixed layer is 18-24 psu. The phytocenosis in this area has a mosaic spatial structure with between-station variation in the shares of different alga groups in the community, cell number of 117-1200 × 106 cells/m2, and a biomass of 1600-3600 mg/m2. As is shown, local inflow of "fresh" nutrients to the euphotic layer in the fall season leads to mass growth of diatoms.

  1. Structure and evolution of the passive margin of the eastern tethys

    NASA Astrophysics Data System (ADS)

    Kazmin, V.; Ricou, L.-E.; Sbortshikov, I. M.

    1986-03-01

    An extensive passive margin was formed in the Triassic along the periphery of Arabia, including the Tauric carbonate platform. This event is related to the opening of the Mesozoic Tethys when a number of microcontinents split off from Gondwana. Triassic extension and continental rifting resulted in the formation of a structural pattern which is uniform from the Dinarides to Oman. It includes the following elements: (1) shelf, (2) continental slope, (3) deep basin probably with a floor of attenuated sialic crust, (4) inner carbonate platform. In the Jurassic-Cretaceous stable conditions prevailed, influenced only by eustatic oscillations of the sea level. Turbidites accumulated on the continental rise while cherts and radiolarites were deposited in the deep basins (Hawasina, Pichakun, Antalya, Pindus) below the CCD level. Sedimentation on the shelf was controlled by north-northeast transverse tectonic elements which also continued across the passive margin, dividing it into a number of segments. Collision with an island arc led to obduction of the oceanic crust, deformation of the passive margin and overthrusting of its sedimentary cover onto the Arabian shelf. Obduction and deformation lasted for about 10 m.y. and created a new tectonic pattern with concentric structural zones surrounding the Arabian promontory. These zones include: (1) the flysch basin—a remnant of the closing Tethys; (2) an uplift—a site of periodical emergence and erosion, corresponding to the frontal part of the ophiolitic nappes; (3) the Border furrow—a depocenter of low-energy calcareous marls, (4) the Arabian shield constantly emerged during the Tertiary. Tectonic deformation of these zones caused by the collision of Arabia with Eurasia began prior to the Early Miocene and it is still going on. Data on Afghanistan demonstrate that its central part (the Gelmend-Argandab and Kabul blocks) belonged during the Paleozoic and Early Mesozoic to the continental shelf of India.

  2. Crustal structure of the Hecataeus Rise (eastern Mediterranean) deduced by marine gravity and marine magnetic modelling

    NASA Astrophysics Data System (ADS)

    Dehghani, Ali

    2016-04-01

    In the year 2010 extensive geophysical researches were carried out in the area of Hecataeus Rise using the German research vessel Maria S. Merian. Beside the bathymetry, refraction and reflection seismic data, marine gravity and marine magnetic data were acquired during this cruise. The result of the research along one Wide-Angle reflection/refraction seismic line of this cruise is published 2015 by K. Welford et al.. Based on interpretation of reflection seismic and bathymetry data across the Hecataeus Rise, S. Reiche published 2015 the crustal structure and bathymetric features along some seismic profiles of this cruise. The focus of this work is to use the available sediments and crustal structures inferred by seismic information together with real marine gravity and marine magnetic data in order to produce gravity and magnetic 2-D models along all seismic profiles. While Welford et al. used the altimetry gravity data and magnetic data from EMAG3 database for their modelling, the real gravity and magnetic data measured exactly along the seismic profiles will be used in this work. The advantage of the real marine gravity and real marine magnetic data used for the modelling is that they have higher accuracy in the values as well as in the positions. Furthermore, Welford et al. calculated the gravity and Magnetic models along some seismic profiles, while in this work the result of gravity and magnetic modelling along all seismic profiles of this cruise will be presented. The marine gravity and marine magnetic data along all seismic profiles were recorded continuously. The accuracy of marine gravity data is about ± 1 mGal, while the accuracy of Marine magnetic data is in the range of ± 3 nT. The results of 2-D gravity and magnetic modelling will be presented and discussed in this work.

  3. Productivity of the spruce grouse in fragmented habitat at the edge of its range

    USGS Publications Warehouse

    Whitcomb, S.D.; O'Connell, A.F.; Servello, F.A.

    1996-01-01

    We measured productivity of the Spruce Grouse (Dendragapusc anadensicsa nadensis) in patchy black spruce (Picea mariana) habitat along the southeastern limit of its range in mid-coastal Maine. We captured grouse and attached necklace-mounted radio transmitters to hens prior to nesting. Of 19 females monitored, only 26% raised chicks to the late brood-rearing period. Predation was high on hens (37%) and five were killed before hatching eggs. Six (55%) entire broods were lost and only 30% of chicks survived to late summer. Production ( No. of chicks/female), an index of productivity, was < 1 and lower in Maine and Minnesota study areas in black spruce than areas dominated by jack pine (Pinus banksiana) or a mixture of jack pine and spruce with dense undergrowth. Where Spruce Grouse breed in patchy black spruce communities, immigration from neighboring populations or inter-patch movement by local individuals may be required to maintain viable populations.

  4. [Community stability for spruce-fir forest at different succession stages in Changbai Mountains, Northeast China].

    PubMed

    Zhang, Meng-tao; Zhang, Qing; Kang, Xin-gang; Yang, Ying-jun; Xu, Guang; Zhang, Li-xin

    2015-06-01

    Based on the analysis of three forest communities (polar-birch secondary forest, spruce-fir mixed forest, spruce-fir near pristine forest) in Changbai Mountains, a total of 22 factors of 5 indices, including the population regeneration, soil fertility (soil moisture and soli nutrient), woodland productivity and species diversity that reflected community characteristics were used to evaluate the stability of forest community succession at different stages by calculating subordinate function values of a model based on fuzzy mathematics. The results that the indices of population regeneration, soli nutrient, woodland productivity and species diversity were the highest in the spruce-fir mixed forest, and the indices of soil moisture were the highest in the spruce-fir near-pristine forest. The stability of three forest communities was in order of natural spruce-fir mixed forest > spruce-fir near pristine forest > polar-birch secondary forest.

  5. Genetic Diversity and Population Structure in Aromatic and Quality Rice (Oryza sativa L.) Landraces from North-Eastern India.

    PubMed

    Roy, Somnath; Banerjee, Amrita; Mawkhlieng, Bandapkuper; Misra, A K; Pattanayak, A; Harish, G D; Singh, S K; Ngachan, S V; Bansal, K C

    2015-01-01

    The North-eastern (NE) India, comprising of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, possess diverse array of locally adapted non-Basmati aromatic germplasm. The germplasm collections from this region could serve as valuable resources in breeding for abiotic stress tolerance, grain yield and cooking/eating quality. To utilize such collections, however, breeders need information about the extent and distribution of genetic diversity present within collections. In this study, we report the result of population genetic analysis of 107 aromatic and quality rice accessions collected from different parts of NE India, as well as classified these accessions in the context of a set of structured global rice cultivars. A total of 322 alleles were amplified by 40 simple sequence repeat (SSR) markers with an average of 8.03 alleles per locus. Average gene diversity was 0.67. Population structure analysis revealed that NE Indian aromatic rice can be subdivided into three genetically distinct population clusters: P1, joha rice accessions from Assam, tai rices from Mizoram and those from Sikkim; P2, aromatic rice accessions from Nagaland; and P3, chakhao rice germplasm from Manipur [corrected]. Pair-wise FST between three groups varied from 0.223 (P1 vs P2) to 0.453 (P2 vs P3). With reference to the global classification of rice cultivars, two major groups (Indica and Japonica) were identified in NE Indian germplasm. The aromatic accessions from Assam, Manipur and Sikkim were assigned to the Indica group, while the accessions from Nagaland exhibited close association with Japonica. The tai accessions of Mizoram along with few chakhao accessions collected from the hill districts of Manipur were identified as admixed. The results highlight the importance of regional genetic studies for understanding diversification of aromatic rice in India. The data also suggest that there is scope for exploiting the genetic diversity of aromatic and

  6. Population genetic structure of a three-host tick, Amblyomma dissimile, in eastern Venezuela.

    PubMed

    Lampo, M; Rangel, Y; Mata, A

    1998-12-01

    Patterns of genetic variation for the tick Amblyomma dissimile were analyzed from a total of 200 ticks collected on 12 toads (Bufo marinus), 14 snakes (Boa constrictor), and 8 lizards (Iguana iguana) at 11 localities. The analyses were performed on electrophoretic data from 8 isozyme loci. Mean heterozygosity per locus was 6% (+/-3.1) per population. Differences in allelic frequencies among ticks from different individual hosts were the major source of genetic variability in this study. Host species was a smaller source of genetic variation. Genetic distances between localities varied according to which host species was present in each locality, and these appeared to be related to the extent of habitat overlap between host species. The smallest genetic distances between samples from different host species were recorded for I. iguana and B. constrictor. In contrast, the genetic distances between tick samples from B. marinus and either of the reptile species were significantly larger than between tick samples from this amphibian species. Ecological variables or the geographic distance did not explain the local patterns of differentiation observed in A. dissimile. Major genetic differences between island and mainland sites (0.03702) suggested an association between genetic distances and geographic isolation. The consistency between patterns of genetic variation and those of host home range overlap suggests that host dispersion is the main force structuring the genetic variation within this tick species.

  7. Abundance, distribution and size structure of Diadema antillarum (Echinodermata: Diadematidae) in South Eastern Cuban coral reefs.

    PubMed

    Martín Blanco, F; González Sansón, G; Pina Amargós, F; Clero Alonso, L

    2010-06-01

    The 1983-1984 mass mortality event of Diadema antillarum affected more than 93% of the total Caribbean population. Although there are no records about the status of Diadema populations before and after die-off on Cuban reefs, anecdotal information suggests that populations were struck. We analyzed spatial variation in the abundance and size structure of D. antillarum in 22 reefs sites in Jardines de la Reina, from June 2004 to September 2005. Counts of Diadema were performed in five 30x2 m transects at each sampling site and sampling time, and test diameters were measured in September 2005 at the same fore reefs. Abundances were higher at reef crests (mean densities 0.08-2.18 ind./m2), while reef slope populations reached a maximum site level of 0.13 ind./m2 at only one site and showed values up to three orders of magnitude lower than those from reef crests. Highest abundance occurred at the west margin of major channels between keys where larval recruitment seems to be favored by local oceanographic features and facilitated by the abundance of Echinometra lucunter. The size frequency distribution of D. antillarum indicates that recruitment began to be noticeable three years before September 2005, suggesting these populations were depleted in the past and they are recovering now.

  8. Hyperspectral data for assessment of temporal changes in Norway spruce forest conditions in the mountainous region of the Czech Republic affected by long-term acidic deposition

    NASA Astrophysics Data System (ADS)

    Albrechtova, J.; Lhotakova, Z.; Misurec, J.; Kopackova, V.; Campbell, P. K. E.; Edwards-Jonasova, M.; Kupkova, L.; Cervena, L.; Potuckova, M.; Cudlin, P.

    2015-12-01

    The Ore Mts. located in the western part of the Czech Republic suffered during 1950's-1990´s heavy atmospheric pollution due to the mining activities and brown coal combustion. Acidic deposition in combination with harsh climatic conditions led there to large-scale forest decline. Although the load of SO2 has significantly decreased since 1991, tree damage was still visible in 1998 in terms of high defoliation or dead trees. Nowadays Norway spruce trees do not exhibit visible symptoms of damage but the full recovery of Norway spruce forests is not complete yet due to persisting adverse soil conditions. The temporal changes in the physiological status of Norway spruce forests in the Krušné Hory Mts. were evaluated using two sets of spectral images acquired in 1998 (ASAS) and in 2013 (APEX) and ground truth data (LAI, tree crown status, photosynthetic pigment contents, leaf spectral properties measured by spectroradiometer, soil properties - pH, contents of basic cations, heavy metals, etc.). Ground truth data were evaluated by unconstrained and constrained multivariate analyses using Canoco 5. The high resolution spectral images (ASAS and APEX) enabled the identification of a gradient of forest conditions and their comparison. In 1998 the stands exhibited different physiological status corresponding to the pollution gradient with healthier trees at the western part of the mountains. Analysis of the foliar chemistry in 2013 show a slight improvement of the Norway spruce physiological status in the eastern part of the mountains while the status of the western-located stands slightly worsened. In 2013 we also studied the differences in soil geochemical conditions, which appeared to be less favorable in the western part of the mountains characterized by a low base cation contents in the top organic horizon and a very low pH (pH<3).

  9. New constraints on the crustal structure in the eastern part of northern Baffin Bay

    NASA Astrophysics Data System (ADS)

    Reichert, C. J.; Damm, V.; Altenbernd, T.; Berglar, K.; Block, M.; Ehrhardt, A.; Schnabel, M.

    2010-12-01

    The northern Baffin Bay is a key area for testing plate kinematic models for the Paleocene-Eocene motion of Greenland relative to North America and to decipher the evolution of the thick sedimentary basins in this area. In summer 2010, a multidisciplinary marine geoscientific expedition focusing on the Greenland part of northern Baffin Bay was performed under the direction of the Federal Institute for Geosciences and Natural Resources Hannover, Germany in cooperation with the Alfred-Wegener Institute Bremerhaven. Using 70 days ship time onboard the German R/V Polarstern a comprehensive data set was acquired along profiles extending from the deep oceanic basin in the central part of North Baffin Bay onto the Greenland continental margin in an area which was bordered by the Kane Basin in the North and Disco Island in the South. By means of multi-channel seismic, wide angle seismic, gravimetric and magnetic methods the structural inventory of the crust in the NW Baffin Bay was investigated. Additionally, heat flow data and sediment cores were collected at selected positions along lines across the Greenland continental margin. The cores were extracted for geochemical and geomicrobiological analysis to be used for basin modeling and studying the hydrocarbon potential. Aeromagnetic data was acquired covering part of the marine survey area to investigate magnetic signatures of the oceanic crust and the continental margin. In our presentation we will give an overview of the first results of the expedition with special focus on multi-channel seismic data. With a total length of 3500 km, the initial interpretation of multi-channel seismic data shows that the West Greenland margin is a typical passive continental margin with large rotated basement blocks, listric faults facing mainly seaward, and deep syn-rift-basins in between. The most prominent reflector under the shelf and the slope probably indicates the transition from rifting to drifting and therefore the beginning of

  10. Group Velocity Tomography for Eastern Mexico and Crustal Structure for Tehuantepec Isthmus

    NASA Astrophysics Data System (ADS)

    Córdoba Montiel, F.; Iglesias, A.; Melgar, D.; Singh, S.; Perez-Campos, X.

    2013-05-01

    We use seismic noise records from the broadband network of the Mexican National Seismological Service (Servicio Sismológico Nacional) and from MASE and VEOX stations (two temporal seismic experiments) to compute the vertical-vertical component of noise cross correlations for station pairs. MASE (Mesoamerican Seismic Experiment) consisted of one hundred stations deployed along a profile perpendicular to the trench and starting in Acapulco,Gro. Mex. This experiment ran from December 2004 until May, 2007. Fifty of these stations were relocated in a N-S profile crossing the Tehuantepec Isthmus from the Gulf of Mexico to the Pacific coast. These stations were operated from July 2007 until February 2009 and this stage of the experiment was called VEOX (Veracruz-Oaxaca). From the cross correlation for each pair of stations, Rayleigh wave dispersion curves were computed which represents the average group velocity between stations pairs. Furthermore, regional earthquakes recorded by the stations, were used to compute Rayleigh wave dispersion curves, which represent the average group velocity between epicenter and station. This mixed set of group velocity measurements was inverted to obtain tomographic images in discrete periods (5-50 s). Resolution tests show that the better-covered regions are surrounding both temporal experiments. Good coverage is also achieved in the large area between both experiments. In order to find details of crustal structure in the Tehuantepec Isthmus we use a set of previously computed receiver functions (Melgar and Pérez-Campos, 2011), to perform a joint inversion together with local dispersion curves reconstructed from the tomographic images. Results show good agreement with previous results by Melgar and Pérez-Campos (2011).

  11. Fatty acids as biomarkers for food web structure in the eastern North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Behrens, J.; Aluwihare, L.; Stephens, B. M.

    2015-12-01

    Resulting from a NSF funded REU program at Scripps Institution of Oceanography in 2015, this research utilized gas chromatography-mass spectrometry (GC-MS) to analyze the fatty acid composition of suspended particulate organic matter (POM) and zooplankton (ZP; primarily copepods). Samples analyzed for this study were collected simultaneously from surface waters approximately 9 miles off the coast of San Diego in June 2015. I was testing the hypothesis that essential fatty acids in ZP should reflect their diet, in particular, distinguishing contributions from a microbial versus traditional food web. Food web structure in this region of the ocean has been shown to be sensitive to climate change on inter-annual and longer timescales. Thus, a proxy that identifies restructuring of food webs would be useful for examining the response of ocean ecosystems to future climate change. Lipids were extracted from ZP and POM using a modified Bligh and Dyer method with sonication. Following saponification free fatty acids and other lipids were further purified using column chromatography. Polar functional groups in lipids were then methylated prior to GC-MS analysis. In addition, 2-dimensional GCxGC with time of flight MS was used to distinguish polyunsaturated fatty acid isomers. My poster will present initial findings of shared fatty acids of zooplankton and POM suspended material from the Northern Pacific collection site. Further research will be focused on analyzing the hydrogen isotope composition of fatty acids in zooplankton and suspended DOM obtained at the collection site to further characterize and increase certainty on the role of microbes and phytoplankton in the region's food-web to distinguish prokaryotic and eukaryotic sources.

  12. 5. View from northwest corner, Spruce Street. Photo shows the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. View from northwest corner, Spruce Street. Photo shows the elevation of Buildings #6 and #1. Doors in the center of the buildings provide a passageway to the interior courtyard of the complex between Buildings #6, #5, #3, and #1. The photo illustrates the pilaster and corbeling of the walls. The photo also shows the coal hopper. - Merrill Silk Mill, 233 Canisteo Street, Hornell, Steuben County, NY

  13. Fish composition and assemblage structure in three Eastern English Channel macrotidal estuaries: A comparison with other French estuaries

    NASA Astrophysics Data System (ADS)

    Selleslagh, Jonathan; Amara, Rachid; Laffargue, Pascal; Lesourd, Sandric; Lepage, Mario; Girardin, Michel

    2009-01-01

    This study has analysed for the first time fish composition and assemblage structures of three small macrotidal estuaries of the Eastern English Channel (EEC) and has explored the influences of 19 biotic and abiotic variables on the fish assemblages. Fish from Canche, Authie and Somme estuaries were collected during spring (June 2006 and May 2007) and autumn (September 2006) along the estuarine gradients using a 1.5 m beam trawl. Using identical sampling protocols, the study also analysed and compared for the first time taxonomic and functional aspects of the fish assemblages in 15 estuaries located along the Atlantic and English Channel coasts. SIMPER analysis showed high similarities in fish assemblages in the three EEC estuaries and during either spring or autumn periods. However, intra-estuary similarities were relatively low, indicating that fish assemblage structures (species richnesses or abundances) were more variable within the estuary (salinity gradient) than between estuaries and/or seasons (spring vs autumn). Although numerous environmental variables were included in the study, only 47% of the variability observed in the fish distribution was explained. Fish spatial variations in the EEC estuaries are mostly driven by abiotic variables as opposed to biological interactions. As indicated by CCA, salinity and muddy sediments were the two most important factors structuring the fish assemblages. The macrobenthos being very abundant in the EEC estuaries (580-1121 ind. m -2), the availability of potential prey is probably not a limiting factor in the utilization of estuaries by fish. Contrary to the majority of French estuaries dominated by estuarine species (ES), the fish assemblages of the EEC estuaries are clearly dominated by marine migrant (MM) species (65% on average) with high abundance of juveniles (mostly young-of-the-year). Cluster and SIMPROF's analyses distinguished the functional structure of the 15 estuarine fish assemblages into different

  14. Ocean-continent-transition and oceanic ridge structural evolution (eastern Gulf of Aden): Implications for rift to seafloor spreading processes

    NASA Astrophysics Data System (ADS)

    D'Acremont, E.; Leroy, S. D.; Beslier, M.; Autin, J.; Watremez, L.; Maia, M. A.; Gente, P.

    2009-12-01

    The rifting between Arabia and Somalia, which started around 35 Ma ago, is followed by oceanic accretion from at least 17.6 Ma leading to the present Gulf of Aden. The transition between the thinned continental and the oceanic crusts is characterized, in space and time, by an ocean-continent transition (OCT). Here, we use bathymetry, gravity, seismic reflection and magnetism from the Encens-Sheba and Encens cruises in order to constrain the structure and segmentation of the conjugate OCT as well as the oceanic ridge between two main fracture zones (Alula-Fartak and Socotra-Hadbeen). The segmentation of the initial oceanic spreading centers seem directly related to the margin structure. Then, magmatic processes and kinematics change strongly influenced the evolution of the segmentation. The OCT and the oceanic domain can be divided into two distinct areas in the study area. The Eastern area is characterized by an extremely thin OCT and oceanic crusts (< 4km), a ~30 km wide and tectonized OCT with isolated continental blocks and short axial segments. In the western area, thicker OCT and oceanic crusts (>5km), a ~15 km wide OCT with a volcanic ridge, and a 6 km thick underplated mafic body in the northern margin suggest a high melt supply. The magmatic supply observed in the western domain is probably due to an off-axis thermal anomaly located below the southern flank of the Sheba ridge, at 75 km east of the major Alula-Fartak transform fault. This suggests that the OCT and the axial ridge morphology of this domain are perturbed by post-rift volcanism, which is due to a combination of the spreading rate, a thermal anomaly, and the cold edge effect of the Alula-Fartak transform fault. The presence of the inherited Mesozoic basins (Jezar-Qamar-Gardafui basin) located on this western domain can also explain, the difference in both the structure and the nature of the OCT between the two domains. The nature of the OCT could be either (or both) exhumed lower crust or

  15. Crustal seismic velocity structure from Eratosthenes Seamount to Hecataeus Rise across the Cyprus Arc, eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Welford, J. Kim; Hall, Jeremy; Hübscher, Christian; Reiche, Sönke; Louden, Keith

    2015-02-01

    Wide-angle reflection/refraction seismic profiles were recorded across the Cyprus Arc, the plate boundary between the African Plate and the Aegean-Anatolian microplate, from the Eratosthenes Seamount to the Hecataeus Rise immediately south of Cyprus. The resultant models were able to resolve detail of significant lateral velocity variations, though the deepest crust and Moho are not well resolved from the seismic data alone. Conclusions from the modelling suggest that (i) Eratosthenes Seamount consists of continental crust but exhibits a laterally variable velocity structure with a thicker middle crust and thinner lower crust to the northeast; (ii) the Hecataeus Rise has a thick sedimentary rock cover on an indeterminate crust (likely continental) and the crust is significantly thinner than Eratosthenes Seamount based on gravity modelling; (iii) high velocity basement blocks, coincident with highs in the magnetic field, occur in the deep water between Eratosthenes and Hecataeus, and are separated and bounded by deep low-velocity troughs and (iv) one of the high velocity blocks runs parallel to the Cyprus Arc, while the other two appear linked based on the magnetic data and run NW-SE, parallel to the margin of the Hecataeus Rise. The high velocity block beneath the edge of Eratosthenes Seamount is interpreted as an older magmatic intrusion while the linked high velocity blocks along Hecataeus Rise are interpreted as deformed remnant Tethyan oceanic crust or mafic intrusives from the NNW-SSE oriented transform margin marking the northern boundary of Eratosthenes Seamount. Eratosthenes Seamount, the northwestern limit of rifted continental crust from the Levant Margin, is part of a jagged rifted margin transected by transform faults on the northern edge of the lower African Plate that is being obliquely subducted under the Aegean-Anatolian upper plate. The thicker crust of Eratosthenes Seamount may be acting as an asperity on the subducting slab, locally locking up

  16. Decadal-Scale Variations in Eastern Pacific Thermocline Structure from Soledad Basin, Baja California

    NASA Astrophysics Data System (ADS)

    Levi, C.; van Geen, A.; Ortiz, J. D.; Zheng, Y.; Marchitto, T. M.; Dean, W. E.; Carriquiry, J.

    2004-12-01

    Soledad Basin, a semi-enclosed basin on the Pacific margin of southern Baja California at 25oN, is ideally located to document past variations of ocean/atmosphere interactions responding to the Pacific Decadal Oscillation (PDO) and the El Nino-Southern Oscillation (ENSO). Very high sedimentation rates (~108 cm/kyr; van Geen et al., Paleoceanography, v. 8, no. 4, 2003) combined with low bottow-water oxygen levels have prevented sediment bioturbation throughout the Holocene, setting the stage for high-resolution paleoclimatic reconstructions in this key climatic area. Current studies of this site focus on the combination of a 210Pb-dated multicore and 14C-dated gravity and piston cores. Available data include a 1-cm resolution diffuse spectral reflectance record, indicative of diagenetic processes linked to productivity (Ortiz et al., Geology, v. 32, no. 6, 2004) and Mg/Ca ratios for several planktonic foraminifera species. Mg/Ca results for two shallow-dwelling species in the multicore indicate little change in sea surface temperature (+/-1.1 deg C) over the mean value of 23 deg C observed over the past two centuries. In contrast, variations of Mg/Ca ratios for a deeper-dwelling species suggest considerably larger temperature variations of +/-1.8 deg C with respect to the mean value of 17.5 deg C at the depth habitat of this species. This suggests fluctuations in the temperature, and therefore nutrient content, of thermocline waters upwelling toward the surface at this site without any appreciable changes in upwelling. Periods of low subsurface temperatures in the water column inferred from Mg/Ca correspond to darker sediment bands, suggesting a connection between the structure of the thermocline, the supply of nutrients to the photic zone, and surface productivity. This interpretation is supported by elevated authigenic Mo concentrations in those same dark bands of 30-40 mg/kg. The presentation will include a comparison of these results with instrumental and other

  17. Structural patterns and tectonic history of the Bauer microplate, Eastern Tropical Pacific

    USGS Publications Warehouse

    Eakins, B.W.; Lonsdale, P.F.

    2003-01-01

    motion. Some structures of the Bauer microplate boundary, such as deep rift valleys and a broad zone of thrust-faulted lithosphere, are, however, similar to those observed around the smaller, active microplates. Analysis of how the Bauer microplate was captured when coupling to the Pacific plate was reduced invites speculation on why risecrest microplates eventually lose their independence. ?? Springer 2005.

  18. Nitrate Reductase of Primary Roots of Red Spruce Seedlings 1

    PubMed Central

    Yandow, Tim S.; Klein, Richard M.

    1986-01-01

    Nitrate reductase activity (NRA) was found in primary roots, but not in foliage of red spruce (Picea rubens Sarg.) seedlings. Nitrate induced NRA:NH4+ did not induce and slightly depressed NRA in older seedlings. Induction required 8 hours and, once induced, NRA decreased slowly in the absence of exogenous NO3−. Seedlings were grown in perlite with a complete nutrient solution containing NH4+ to limit NR induction. Established seedlings were stressed with nutrient solutions at pH 3, 4, or 5 supplemented with Cl− salts of Al, Cd, Pb, or Zn each at two concentrations. NRA in primary root tips was measured at 2, 14, 28, and 42 days. NRA induction was greatest at pH 3, and remained high during the period of study. NRA induction at pH 4 was lower. Metal ions suppressed NRA at pH 3 and 5, but enhanced NRA at pH 4. It is concluded that acidity and soluble metals in the root environment of red spruce are unlikely to be important factors in nitrogen transformations in red spruce roots. PMID:16664891

  19. Fertility of soils under spruce forests of the Khibiny Mountains

    NASA Astrophysics Data System (ADS)

    Orlova, M. A.; Lukina, N. V.; Smirnov, V. E.; Krasnov, D. A.; Kamaev, I. O.

    2012-06-01

    The development of fertility of soils on different parent rocks is considered for different types of spruce forests in the Khibiny Mountains. The spruce forests of Mts. Kuel'por, Vud'yavrchorr, Chil'mana, and Saami were the objects for the study. The results showed that the fertility level of the soils of the Khibiny Mountains was determined by the combined influence of the parent rock's composition and the vegetation. The differences in the soil properties are mainly explained by the composition of the parent rocks. The pod-burs differ from the podzols by the higher contents of organic matter, nitrogen, and available nutrients. The podzols are the most acid soils there. The podburs of Mt Kuel'por developing on base-rich parent rocks are the most fertile. The differences in the fertility of the soils on the intrabiogeocenotic (tessera) level are related to the vegetation. The soils of the spruce and tall-grass tesseras are richer in nitrogen, calcium, and manganese as compared to the soils of the dwarf shrub-green moss, low-grass-dwarf shrub-green moss, and tussock grass-dwarf shrub tesseras.

  20. Wood energy fuel cycle optimization in beech and spruce forests

    NASA Astrophysics Data System (ADS)

    Meyer, Nickolas K.; Mina, Marco

    2012-03-01

    A novel synergistic approach to reducing emissions from residential wood combustion (RWC) is presented. Wood energy fuel cycle optimization (FCO) aims to provide cleaner burning fuels through optimization of forestry and renewable energy management practices. In this work, beech and spruce forests of average and high quality were modelled and analysed to determine the volume of fuel wood and its associated bark fraction produced during typical forestry cycles. Two separate fuel wood bark production regimes were observed for beech trees, while only one production regime was observed for spruce. The single tree and stand models were combined with existing thinning parameters to replicate existing management practices. Utilizing estimates of initial seedling numbers and existing thinning patterns a dynamic model was formed that responded to changes in thinning practices. By varying the thinning parameters, this model enabled optimization of the forestry practices for the reduction of bark impurities in the fuel wood supply chain. Beech forestry cycles responded well to fuel cycle optimization with volume reductions of bark from fuel wood of between ˜10% and ˜20% for average and high quality forest stands. Spruce, on the other hand, was fairly insensitive to FCO with bark reductions of 0-5%. The responsiveness of beech to FCO further supports its status as the preferred RWC fuel in Switzerland. FCO could easily be extended beyond Switzerland and applied across continental Europe and North America.

  1. Active tectonics of the Devils Mountain Fault and related structures, northern Puget Lowland and eastern Strait of Juan de Fuca region, Pacific Northwest

    USGS Publications Warehouse

    Johnson, Samuel Y.; Dadisman, Shawn V.; Mosher, David C.; Blakely, Richard J.; Childs, Jonathan R.

    2001-01-01

    Information from marine high-resolution and conventional seismic-reflection surveys, aeromagnetic mapping, coastal exposures of Pleistocene strata, and lithologic logs of water wells is used to assess the active tectonics of the northern Puget Lowland and eastern Strait of Juan de Fuca region of the Pacific Northwest. These data indicate that the Devils Mountain Fault and the newly recognized Strawberry Point and Utsalady Point faults are active structures and represent potential earthquake sources.

  2. Hydraulic properties and inner structure of a relict rock glacier in the Eastern Alps, Austria

    NASA Astrophysics Data System (ADS)

    Pauritsch, Marcus; Winkler, Gerfried; Kellerer-Pirklbauer, Andreas; Birk, Steffen

    2013-04-01

    Water economic studies in 1990s documented the importance of the springs draining relict rock glaciers for water supply and human consumption as well as for the ecosystem in alpine catchments in the Niederen Tauern Range, Austria. Recent studies confirm the hydrologic importance and show that in the easternmost subunit, the Seckauer Tauern Range, more than 40% of the area above 2000 m a.s.l. and up to 20% of the area above 1500 m a.s.l. drain through relict rock glaciers. Thus, the hydraulic properties of these alpine aquifers are considered to be important controls on the hydrology of these areas. Nevertheless their hydraulic properties and their inner structure are still poorly understood. Our hydrogeological research is carried out at the Schöneben Rock Glacier, located in Seckauer Tauern Range, Austria. This rock glacier is presumably relict although patches of permafrost might exist particularly in the upper part of the landform. The rock glacier covers an area of 0.11 km² and drains a total catchment of 0.76 km² with a maximum elevation of 2282 m a.s.l.. The rock glacier consists predominantly of gneissic sediments (mainly coarse-grained, blocky at the surface) and extends from 1720 to 1905 m a.s.l.. Discharge of the rock glacier spring is recorded since 2002. Electrical conductivity and water temperature used as natural tracers are continuously monitored since 2008. Furthermore, a tracer test with simultaneous injection of the fluorescent dyes naphthionate and fluoresceine at two injection points (one close to the front and one close to the rooting zone of the rock glacier) was performed. Recession analysis of the spring hydrograph reveals similarities to the flow dynamics of karst springs. The results exhibit on the one hand a slow base flow recession indicating a high storage capacity and on the other hand sharp discharge peaks immediately after rainfall events referring to a high hydraulic conductivity. Applying different analytic runoff models, the

  3. Crustal and uppermost mantle structure of the eastern margin of the Yilgarn Craton (Australia) from passive seismic data

    NASA Astrophysics Data System (ADS)

    Sippl, Christian; Tkalčić, Hrvoje; Kennett, Brian; Spaggiari, Catherine; Gessner, Klaus

    2016-04-01

    The Yilgarn Craton in Western Australia is one of the largest units of Archean lithosphere on earth. Along its southern and southeastern margin, it is bounded by the Albany-Fraser Orogen (AFO), a Paleo- to Mesoproterozoic extensioal-accretionary orogen. In this contribution, we investigate the crustal and upper mantle structure of the AFO and adjacent regions using passive seismic data collected during the recent ALFREX experiment. Since the entire region has not been significantly reactivated since the Mesoproterozoic, the old signature of craton edge modification should have been well preserved until today. From November 2013 until January 2016, we operated a temporary passive seismic network consisting of 70 stations in the eastern Albany-Fraser Orogen. The array had an average station spacing of about 40 km and was designed to fill the gap between recently acquired active seismic profiles. We present results from the analysis of P receiver functions and ambient noise tomography using the ALFREX data. Receiver functions were used to derive a Moho depth map via H-K stacking, for direct imaging (common conversion point stacking) as well as joint inversion with surface wave dispersion data to derive 1D S-velocity profiles beneath the stations. The obtained receiver functions show a marked change of character from west to east across the array. Whereas they feature clear and sharp Moho phases for stations on the Yilgarn Craton, significantly more crustal complexity and fainter Moho phases are seen throughout the AFO. Crustal thickness increases from 36-39 km for the Yilgarn Craton to values between 42 and 48 km across the AFO, decreasing to around 40 km in the east. Ambient noise cross-correlations were used to derive maps of phase and group velocities of Rayleigh waves at periods between 1 and 30 seconds. A three-dimensional model of S wavespeeds throughout the area was then computed by pixelwise inversion of dispersion curves. Obtained S wavespeeds are generally

  4. Fire Severity Controlled Susceptibility to a 1940s Spruce Beetle Outbreak in Colorado, USA

    PubMed Central

    Kulakowski, Dominik; Veblen, Thomas T.; Bebi, Peter

    2016-01-01

    The frequency, magnitude, and size of forest disturbances are increasing globally. Much recent research has focused on how the occurrence of one disturbance may affect susceptibility to subsequent disturbances. While much has been learned about such linked disturbances, the strength of the interactions is likely to be contingent on the severity of disturbances as well as climatic conditions, both of which can affect disturbance intensity and tree resistance to disturbances. Subalpine forests in western Colorado were affected by extensive and severe wildfires in the late 19th century and an extensive and severe outbreak of spruce beetle (Dendroctonus rufipennis) in the 1940s. Previous research found that most, but not all, of the stands that burned and established following the late 19th century fires were not susceptible to the 1940s outbreak as beetles preferentially attack larger trees and stands in advanced stages of development. However, previous research also left open the possibility that some stands that burned and established following the 19th century fires may have been attacked during the 1940s outbreak. Understanding how strongly stand structure, as shaped by disturbances of varying severity, affected susceptibility to past outbreaks is important to provide a baseline for assessing the degree to which recent climate change may be relaxing the preferences of beetles for larger trees and for stands in latter stages of structural development and thereby changing the nature of linked disturbances. Here, dendroecological methods were used to study disturbance history and tree age of stands in the White River National Forest in Western Colorado that were identified in historical documents or remotely-sensed images as having burned in the 19th century and having been attacked by spruce beetle in the 1940s. Dendroecological reconstructions indicate that in young post-fire stands only old remnant trees that survived the otherwise stand-replacing fires were

  5. Crustal structure from the Hecataeus Rise to the Levantine Basin, eastern Mediterranean, from seismic refraction and gravity modelling

    NASA Astrophysics Data System (ADS)

    Welford, J. Kim; Hall, J.; Rahimi, A.; Reiche, S.; Hübscher, C.; Louden, K.

    2015-12-01

    In 2010, a wide-angle seismic reflection/refraction profile was acquired along the Hecataeus Rise, an area of shallow seabed immediately south of Cyprus in the eastern Mediterranean. The profile crossed from the Hecataeus Rise, through the Cyprus Arc to the Levantine Basin beyond. Due to the short length of the profile and the corresponding lack of deep ray coverage, velocity modelling was complemented by gravity modelling to gain constraints on deep crustal structure. The resultant model reveals velocities for the Hecataeus Rise that show no evidence of shallow ophiolites like those seen on mainland Cyprus, and the velocities are not diagnostic of a unique crustal affinity. Low-velocity sediments make up at least 7 km of the upper structure of Hecataeus Rise and these sediments overlie a two-layered crust. From the gravity modelling, the combined sediments and crust of Hecataeus Rise appear to be thinner than the Eratosthenes Seamount block to the southwest. A high-velocity lower crustal block is modelled under the seaward edge of Hecataeus Rise and, based on the gravity modelling, is inferred to extend landwards beneath the Rise. Similar high-velocity blocks were identified on the southwestern edge of Hecataeus Rise along nearby refraction lines and were interpreted as remnant Tethyan oceanic crust, foundered in the Cyprus Arc, along which subduction has ceased in this area. Given the thin two-layered crust beneath a thick accumulation of sediments modelled for Hecataeus Rise, we interpret that Hecataeus Rise represents a collage of oceanic fragments, accreted together within the failed subduction zone. Outboard of the crust of Hecataeus Rise, a 5-km deep low-velocity basin, possibly an accretionary wedge, is imaged that appears to correspond with the Cyprus Arc deformation zone imaged on both coincident and along-strike seismic reflection lines. A similar and wider feature is observed on seismic refraction lines to the west and combined, these may be revealing

  6. Crustal structure beneath the High Lava Plains of eastern Oregon and surrounding regions from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Eagar, Kevin C.; Fouch, Matthew J.; James, David E.; Carlson, Richard W.

    2011-02-01

    We analyze teleseismic P-to-S receiver functions to image crustal structure beneath the High Lava Plains (HLP) of eastern Oregon and surrounding regions. Coverage from 206 broadband seismic stations provides the first opportunity to resolve variations in crustal composition, thickness, and heterogeneity on scales of a few km in depth and tens of km laterally across the HLP region. We utilize both H - κ stacking and a new Gaussian-weighted common conversion point stacking technique. We find crust that is ≥40 km thick beneath the Cascades, Idaho Batholith, and Owyhee Plateau and thinner (˜31 km) crust beneath the HLP and northern Great Basin. Low Poisson's ratios of ˜0.240 characterize the granitic crust beneath the Idaho Batholith, while the Owyhee Plateau exhibits values of ˜0.270, typical of average continental crust. The Owyhee Plateau is a thick simple crustal block with distinct edges at depth. The western HLP exhibits high average values of 0.304, typical for regions of widespread basaltic volcanism. Combined with other geological and geophysical observations, the areas of abnormally high Poisson's ratios (˜0.320) and low-velocity zones in the crust beneath north-central and southern Oregon are consistent with the presence of partial melt on either side of the HLP trend, suggesting a central zone where crustal melts have drained to the surface, perhaps enabled by the Brothers Fault Zone. Thicker crust and an anomalous N-S band of low Poisson's ratios (˜0.252) skirting the Steens Mountain escarpment is consistent with residuum from a midcrustal magma source of the massive flood basalts, supporting the view of extensive mafic underplating and intraplating of the crust from Cenozoic volcanism.

  7. An integrated structural and geochemical study of fracture aperture growth in the Campito Formation of eastern California

    NASA Astrophysics Data System (ADS)

    Doungkaew, N.; Eichhubl, P.

    2015-12-01

    Processes of fracture formation control flow of fluid in the subsurface and the mechanical properties of the brittle crust. Understanding of fundamental fracture growth mechanisms is essential for understanding fracture formation and cementation in chemically reactive systems with implications for seismic and aseismic fault and fracture processes, migration of hydrocarbons, long-term CO2 storage, and geothermal energy production. A recent study on crack-seal veins in deeply buried sandstone of east Texas provided evidence for non-linear fracture growth, which is indicated by non-elliptical kinematic fracture aperture profiles. We hypothesize that similar non-linear fracture growth also occurs in other geologic settings, including under higher temperature where solution-precipitation reactions are kinetically favored. To test this hypothesis, we investigate processes of fracture growth in quartzitic sandstone of the Campito Formation, eastern California, by combining field structural observations, thin section petrography, and fluid inclusion microthermometry. Fracture aperture profile measurements of cemented opening-mode fractures show both elliptical and non-elliptical kinematic aperture profiles. In general, fractures that contain fibrous crack-seal cement have elliptical aperture profiles. Fractures filled with blocky cement have linear aperture profiles. Elliptical fracture aperture profiles are consistent with linear-elastic or plastic fracture mechanics. Linear aperture profiles may reflect aperture growth controlled by solution-precipitation creep, with the aperture distribution controlled by solution-precipitation kinetics. We hypothesize that synkinematic crack-seal cement preserves the elliptical aperture profiles of elastic fracture opening increments. Blocky cement, on the other hand, may form postkinematically relative to fracture opening, with fracture opening accommodated by continuous solution-precipitation creep.

  8. Genetic structure of red-handed howler monkey populations in the fragmented landscape of Eastern Brazilian Amazonia

    PubMed Central

    2010-01-01

    We genotyped 15 microsatellite loci in order to evaluate the effects of habitat fragmentation, caused by flooding of the Tucuruí reservoir, on the genetic structure of Alouatta belzebul in eastern Amazonia. The analysis included two populations sampled in 1984, representing both margins of the Tocantins river, and three populations sampled 18 years later. Minimal differences in the diversity levels between present-day (Ho = 0.62-0.69 and AR = 6.07-7.21) and pre-flooding (Ho = 0.60-0.62 and A R = 6.27-6.77) populations indicated there was no significant loss of genetic variability, possibly because of successful management strategies applied during the flooding. The changes observed were limited to shifts in the composition of alleles, which presumably reflect the admixture of subpopulations during flooding. Given this, there were significant differences in the Rst values (p = 0.05) in all but one between-site comparison. Both present-day and original populations showed a deficit of heterozygotes, which suggests that this may be typical of the species, at least at a local level, perhaps because of specific ecological characteristics. The relatively large number of private alleles recorded in all populations may be a consequence of the Wahlund effect resulting from population admixture or a process of expansion rather than the loss of rare alleles through genetic drift. Additionally, the levels of genetic variability observed in this study were higher than those reported for other species of Neotropical primates, suggesting good fitness levels in these A. belzebul populations. Regular genetic monitoring of remnant populations, especially on islands, should nevertheless be an integral component of long-term management strategies. PMID:21637590

  9. Genetic structure of red-handed howler monkey populations in the fragmented landscape of Eastern Brazilian Amazonia.

    PubMed

    Bastos, Heitor B; Gonçalves, Evonnildo C; Ferrari, Stephen F; Silva, Artur; Schneider, Maria Paula C

    2010-10-01

    We genotyped 15 microsatellite loci in order to evaluate the effects of habitat fragmentation, caused by flooding of the Tucuruí reservoir, on the genetic structure of Alouatta belzebul in eastern Amazonia. The analysis included two populations sampled in 1984, representing both margins of the Tocantins river, and three populations sampled 18 years later. Minimal differences in the diversity levels between present-day (Ho = 0.62-0.69 and A(R) = 6.07-7.21) and pre-flooding (Ho = 0.60-0.62 and A (R) = 6.27-6.77) populations indicated there was no significant loss of genetic variability, possibly because of successful management strategies applied during the flooding. The changes observed were limited to shifts in the composition of alleles, which presumably reflect the admixture of subpopulations during flooding. Given this, there were significant differences in the Rst values (p = 0.05) in all but one between-site comparison. Both present-day and original populations showed a deficit of heterozygotes, which suggests that this may be typical of the species, at least at a local level, perhaps because of specific ecological characteristics. The relatively large number of private alleles recorded in all populations may be a consequence of the Wahlund effect resulting from population admixture or a process of expansion rather than the loss of rare alleles through genetic drift. Additionally, the levels of genetic variability observed in this study were higher than those reported for other species of Neotropical primates, suggesting good fitness levels in these A. belzebul populations. Regular genetic monitoring of remnant populations, especially on islands, should nevertheless be an integral component of long-term management strategies.

  10. Using forensic microsatellites to decipher the genetic structure of linguistic and geographic isolates: A survey in the eastern Italian Alps.

    PubMed

    Montinaro, Francesco; Boschi, Ilaria; Trombetta, Federica; Merigioli, Sara; Anagnostou, Paolo; Battaggia, Cinzia; Capocasa, Marco; Crivellaro, Federica; Destro Bisol, Giovanni; Coia, Valentina

    2012-12-01

    The study of geographically and/or linguistically isolated populations could represent a potential area of interaction between population and forensic genetics. These investigations may be useful to evaluate the suitability of loci which have been selected using forensic criteria for bio-anthropological studies. At the same time, they give us an opportunity to evaluate the efficiency of forensic tools for parentage testing in groups with peculiar allele frequency profiles. Within the frame of a long-term project concerning Italian linguistic isolates, we studied 15 microsatellite loci (Identifiler kit) comprising the CODIS panel in 11 populations from the north-eastern Italian Alps (Veneto, Trentino and Friuli Venezia Giulia regions). All our analyses of inter-population differentiation highlight the genetic distinctiveness of most Alpine populations comparing them either to each other or with large and non-isolated Italian populations. Interestingly, we brought to light some aspects of population genetic structure which cannot be detected using unilinear polymorphisms. In fact, the analysis of genotypic disequilibrium between loci detected signals of population substructure when all the individuals of Alpine populations are pooled in a single group. Furthermore, despite the relatively low number of loci analyzed, genetic differentiation among Alpine populations was detected at individual level using a Bayesian method to cluster multilocus genotypes. Among the various populations studied, the four linguistic minorities (Fassa Valley, Luserna, Sappada and Sauris) showed the most pronounced diversity and signatures of a peculiar genetic ancestry. Finally, we show that database replacement may affect estimates of probability of paternity even when the local database is replaced by another based on populations which share a common genetic background but which differ in their demographic history. These findings point to the importance of considering the demographic and

  11. Cumulative potential hydrologic impacts of surface coal mining in the eastern Powder River structural basin, northeastern Wyoming

    USGS Publications Warehouse

    Martin, L.J.; Naftz, D.L.; Lowham, H.W.; Rankl, J.G.

    1988-01-01

    There are 16 existing and six proposed surface coal mines in the eastern Powder River structural basin of northeastern Wyoming. Coal mining companies predict water level declines of 5 ft or more in the Wasatch aquifer to extend form about 1,000 to about 2,000 ft beyond the mine pits. The predicted 5 ft water level decline in the Wyodak coal aquifer generally extends 4-8 mi beyond the lease areas. About 3,000 wells are in the area of potential cumulative water level declines resulting from all anticipated mining. Of these 3,000 wells, about 1,200 are outside the areas of anticipated mining: about 1,000 wells supply water for domestic or livestock uses, and about 200 wells supply water for municipal, industrial, irrigation, and miscellaneous uses. The 1,800 remaining wells are used by coal mining companies. Future surface coal mining probably will result in postmining groundwater of similar quality to that currently present in the study area. By use of geochemical modeling techniques, the results of a hypothetical reaction path exercise indicate the potential for marked improvements in postmining water quality because of chemical reactions as postmining groundwater with a large dissolved solids concentration (3,540 mg/L) moves into a coal aquifer with relatively small dissolved solids concentrations (910 mg/L). Results of the modeling exercise also indicate geochemical conditions that are most ideal for large decreases in dissolved solids concentrations in coal aquifers receiving recharge from a spoil aquifer. (Lantz-PTT)

  12. Effects of NaCl on responses of ectomycorrhizal black spruce (Picea mariana), white spruce (Picea glauca) and jack pine (Pinus banksiana) to fluoride.

    PubMed

    Calvo-Polanco, Mónica; Zwiazek, Janusz J; Jones, Melanie D; MacKinnon, Michael D

    2009-01-01

    Black spruce (Picea mariana), white spruce (Picea glauca) and jack pine (Pinus banksiana) were inoculated with Suillus tomentosus and subjected to potassium fluoride (1 mM KF and 5 mM KF) in the presence and absence of 60 mM NaCl. The NaCl and KF treatments reduced total dry weights in jack pine and black spruce seedlings, but they did not affect total dry weights in white spruce seedlings. The addition of 60 mM NaCl to KF treatment solutions alleviated fluoride-induced needle injury in ectomycorrhizal (ECM) black spruce and white spruce, but had little effect in jack pine seedlings. Both KF and 60 mM NaCl treatments reduced E values compared with non-treated control seedlings. However, with the exception of small reductions of K(r) by NaCl treatments in black spruce, the applied KF and NaCl treatments had little effect on K(r) in ECM plants. Chloride tissue concentrations in NaCl-treated plants were not affected by the presence of KF in treatment solutions. However, shoot F concentrations in ECM black spruce and white spruce treated with 5 mM KF + 60 mM NaCl were significantly reduced compared with the 5 mM KF treatment. The results point to a possible competitive inhibition of F transport by Cl. We also suggest that the possibility that aquaporins may be involved in the transmembrane transport of F should be further investigated.

  13. Evaluation of genetic variability in a small, insular population of spruce grouse

    USGS Publications Warehouse

    O'Connell, A.F.; Rhymer, J.; Keppie, D.M.; Svenson, K.L.; Paigan, B.J.

    2002-01-01

    Using microsatellite markers we determined genetic variability for two populations of spruce grouse in eastern North America, one on a coastal Maine island where breeding habitat is limited and highly fragmented, the other in central New Brunswick (NB), where suitable breeding habitat is generally contiguous across the region. We examined six markers for both populations and all were polymorphic. Although the number of alleles per locus and the proportion of unique alleles were lower in the island population, and probably a result of small sample.size, heterozygosity and a breeding coefficient (Fis) indicated slightly more variability in the island population. Deviation from Hardy-Weinberg equilibrium also was more evident in loci for the mainland population. Several traits previously documented in the island population: relatively long natal dispersal distances, reproductive success, territoriality, adult survival, and longevity support the maintenance of hetrerzygosity, at least in the short-term. Sample collection from two small (500 ha), separate areas in NB, and the predicted importance of immigration density to supplement this population demonstrate the need for behavioral and ecological information when interpreting genetic variation. We discuss the relevance of these issues with respect to genetic variability and viability.

  14. Disturbance and climatic effects on red spruce community dynamics at its southern continuous range margin

    PubMed Central

    2014-01-01

    Red spruce (Picea rubens) populations experienced a synchronous rangewide decline in growth and vigor starting in the 1960s, likely caused by climate change and a combination of environmental disturbances. However, it is not yet known if populations continue to decline or have recovered. Red spruce growing near its southern range margin in Massachusetts is a species of concern, in light of the vulnerability to climate change. This study uses population data from 17 permanent plots coupled with tree-ring data to examine radial growth rates, determine the growth-climate relationship, and document disturbance events. Red spruce at these plots ranged from 90 to 184 years old, and comprised 15 to 29 m2/ha basal area. Red spruce seedlings and saplings were common at plots with previously high overstory spruce abundance, indicating it could return to a more dominant position under favorable growing conditions. However, permanent plot measures over a 50 year time span did not indicate any consistent trends for changes in basal area or density for red spruce or other woody species. Climate data show that mean annual minimum, maximum, and summer temperatures have increased over the last 100 years. Dendroclimatological analyses indicated that red spruce growth was sensitive to both temperature and precipitation. Prior to the 1960s, spruce at these sites showed a positive response to precipitation; however after a multi-year drought in the 1960s showed an increasingly negative correlation with precipitation. There has been a negative growth response to regional warming, as spruce radial growth was mostly constrained by increasing temperatures, potentially coupled with the associated increasing drought-dress. I suggest the change in climate response is potentially due to a physiological threshold response to increasing temperatures, which may cause spruce to continue to decline or be lost from the lower elevation sites, while the high elevation sites has a persistent spruce

  15. Genetic structure and diversity of indigenous rice (Oryza sativa) varieties in the Eastern Himalayan region of Northeast India.

    PubMed

    Choudhury, Baharul; Khan, Mohamed Latif; Dayanandan, Selvadurai

    2013-12-01

    The Eastern Himalayan region of Northeast (NE) India is home to a large number of indigenous rice varieties, which may serve as a valuable genetic resource for future crop improvement to meet the ever-increasing demand for food production. However, these varieties are rapidly being lost due to changes in land-use and agricultural practices, which favor agronomically improved varieties. A detailed understanding of the genetic structure and diversity of indigenous rice varieties is crucial for efficient utilization of rice genetic resources and for developing suitable conservation strategies. To explore the genetic structure and diversity of rice varieties in NE India, we genotyped 300 individuals of 24 indigenous rice varieties representing sali, boro, jum and glutinous types, 5 agronomically improved varieties, and one wild rice species (O. rufipogon) using seven SSR markers. A total of 85 alleles and a very high level of gene diversity (0.776) were detected among the indigenous rice varieties of the region. Considerable level of genetic variation was found within indigenous varieties whereas improved varieties were monoporphic across all loci. The comparison of genetic diversity among different types of rice revealed that sali type possessed the highest gene diversity (0.747) followed by jum (0.627), glutinous (0.602) and boro (0.596) types of indigenous rice varieties, while the lowest diversity was detected in agronomically improved varieties (0.459). The AMOVA results showed that 66% of the variation was distributed among varieties indicating a very high level of genetic differentiation in rice varieties in the region. Two major genetically defined clusters corresponding to indica and japonica groups were detected in rice varieties of the region. Overall, traditionally cultivated indigenous rice varieties in NE India showed high levels of genetic diversity comparable to levels of genetic diversity reported from wild rice populations in various parts of the

  16. In vitro fungistatic effects of natural coniferous resin from Norway spruce (Picea abies).

    PubMed

    Rautio, M; Sipponen, A; Lohi, J; Lounatmaa, K; Koukila-Kähkölä, P; Laitinen, K

    2012-08-01

    Resins (rosin, pitch) are natural products of the coniferous trees and are antimicrobial against a wide range of microbes. The antifungal effectiveness of resin, purified from Norway spruce (Picea abies), was studied against human pathogenic fungi and yeasts with the agar plate diffusion tests and electron microscopy (EM). The fungistatic effect of these resin mixtures (resin salves) was tested against a set of Candida yeasts, dermatophytes, and opportunistic fungi. Transmission and scanning EM was done from samples of fungi (Trichophyton mentagrophytes). In agar diffusion tests, the resin was strongly antifungal against all dermatophytes tested, e.g., against all fungi of the genus Trichophyton, but it was not antifungal against the Candida yeasts or against the opportunistic fungi tested. According to EM, resin caused damages in the cell hyphae and cell wall structures. We conclude that, in the agar plate diffusion test, coniferous resins are strongly fungistatic against the dermatophytic fungi only.

  17. Hartig' net formation of Tricholoma vaccinum-spruce ectomycorrhiza in hydroponic cultures.

    PubMed

    Henke, Catarina; Jung, Elke-Martina; Kothe, Erika

    2015-12-01

    For re-forestation of metal-contaminated land, ectomycorrhizal trees may provide a solution. Hence, the study of the interaction is necessary to allow for comprehensive understanding of the mutually symbiotic features. On a structural level, hyphal mantle and the Hartig' net formed in the root apoplast are essential for plant protection and mycorrhizal functioning. As a model, we used the basidiomycete Tricholoma vaccinum and its host spruce (Picea abies). Using an optimized hydroponic cultivation system, both features could be visualized and lower stress response of the tree was obtained in non-challenged cultivation. Larger spaces in the apoplasts could be shown with high statistical significance. The easy accessibility will allow to address metal stress or molecular responses in both partners. Additionally, the proposed cultivation system will enable for other experimental applications like addressing flooding, biological interactions with helper bacteria, chemical signaling, or other biotic or abiotic challenges relevant in the natural habitat.

  18. Doctoring in Eastern Europe

    PubMed Central

    Wilde, Henry

    1983-01-01

    Health care in Eastern Europe has not achieved world standards nor the goals of planners of socialist societies. With luck, perseverance, bribes or good connections, it is possible to obtain good medical and surgical care in Eastern Europe for a major illness. Primary and even secondary care usually are substandard, however, and often completely unacceptable to most Western foreigners. The reasons for this are complex but mainly rooted in different attitudes of health workers towards their patients, poor physical plants, poor salary structures, inadequate advancement opportunities for health care workers, poor social status and professional recognition for nurses and almost complete isolation of the average primary care doctor from hospital medicine. PMID:6659504

  19. Accumulation of organic air constituents by plant surfaces. Spruce needles for monitoring airborne chlorinated hydrocarbons

    SciTech Connect

    Reischl, A.; Thoma, H.; Reissinger, M.; Hutzinger, O. )

    1988-10-01

    The needles of the spruce (Picea abies) were used to monitor ambient air for organic trace substances. Analyses of spruce needles in an industrialized area demonstrated that the concentrations of these substances were much higher than those in a nonindustrialized area.

  20. Numerical simulation of structural evolution from regional to local scale in the Outokumpu ore district, eastern Finland

    NASA Astrophysics Data System (ADS)

    Zhang, Yanhua; Sorjonen-Ward, Peter; Ord, Alison; Kontinen, Asko

    2015-04-01

    Numerical simulations of geological processes may be used in several ways. On the one hand there is an analytical, or forensic approach, analogous to geophysical inversion, to constrain boundary conditions and to demonstrate how a particular geological process or sequence of events is feasible, or even probable. Alternatively, or additionally, modeling of earth processes can be used in a predictive sense, where forward modeling of various scenarios representing different initial states and applied boundary conditions and processes can provide generic or specific insights - depending on model complexity - which may be applied to problems as diverse as geohazard risk assessment and mineral exploration. These two approaches are complementary, and either may be emphasized, depending on the degree of understanding or density of data in a given study area. Here we review how the results of modeling can be used to develop and test structural scenarios and hypotheses and how they can be integrated with new data sets, in this case, deep crustal and upper crustal high resolution reflection seismic data acquired in recent years in the Paleoproterozoic Outokumpu ore district in eastern Finland. A range of process models have been devised and run for the Outokumpu mineral system, including coupled convective reactive transport models, coupled thermomechanical models assessing thermal regimes in rifting, and coupled mechanical and fluid flow models, but here we focus on the results of mechanical modeling using the finite element code FLAC. Models designed at different scales have provided simple and plausible solutions that affirm the geometric and kinematic scenarios based on regional and mine-scale structural data. At regional scale, FLAC models effectively simulated the partitioning of deformation into NW-SE trending ductile shear zones and domains where coeval folding and thrusting have NE-trending axial trends. At a more detailed district scale, development of local

  1. Forceful emplacement of the Eureka Valley-Joshua Flat-Beer Creek composite pluton into a structural basin in eastern California; internal structure and wall rock deformation

    NASA Astrophysics Data System (ADS)

    Morgan, Sven; Law, Richard; de Saint Blanquat, Michel

    2013-11-01

    Anisotropy of Magnetic Susceptibility parameters have been analyzed at 311 locations in the Eureka Valley-Joshua Flat-Beer Creek (EJB) pluton of eastern California. The large amount of data has allowed for the AMS parameters to be contoured using techniques that both reveal map-scale trends and emphasize small-scale differences. The contour maps suggest that magnetic susceptibility is dominantly controlled by composition of the magma but may also be affected by emplacement-related strain as the magma chamber inflated and forced the wall rocks outward. Pluton construction involved two major pulses of different composition magmas that were emplaced sequentially but with overlapping periods of crystallization. The magmas initially intruded as sill-like bodies into a structural basin. The magnetic foliation of the pluton cuts across internal magmatic contacts on the map scale and is parallel to local contacts between the pluton and surrounding metasedimentary wall rocks. The magnetic fabric is similar in orientation and symmetry to intense flattening strains recorded in the aureole rocks. The metasedimentary wall rocks have been shortened between 60 and 70% and this strain magnitude is approximately equal on the west, south, and east margins of the pluton. Strain in the wall rocks is dominantly flattening and concentrated into a narrow (1 km wide) inner aureole. Mapping of bedding/cleavage intersection lineations south of the pluton indicates that the magma made room for itself by translating the wall rocks outward and rotating the already inward dipping wall rocks of the structural basin to sub-vertical. Stretching of the inner aureole around an expanding magma chamber was responsible for the intense shortening. Limited data on the Marble Canyon pluton to the south of the EJB pluton indicates a very similar emplacement process.

  2. Measuring spectral effects of calcium fertilization in the red spruce foliage

    NASA Astrophysics Data System (ADS)

    Kessler, W. R.; Rock, B. N.; Hallett, R. A.

    2007-12-01

    Acidic precipitation has altered biogeochemical cycles in the forests of the Northeastern U.S., and has lead to an interest in the decline symptomology of tree species affected as a result of these changes. For instance, in red spruce (Picea rubens Sarg.) stands, leaching losses of calcium (Ca) may hamper root uptake capacities, wood structural properties, and tolerance of low temperature. The Hubbard Brook Experimental Forest (HBEF) is currently the site of a long-term Ca investigation, where an entire watershed was fertilized with wollastonite (CaSiO3) at the rate of 0.12 kg ha-1 in 1999. Preliminary data confirm that Ca-treated spruce foliage is higher in total foliar Ca as compared to foliage from trees in a reference watershed. Total foliar Ca concentration, as well as that of a bound Ca-oxalate pool, increase with needle age class. In order to test the utility of hyperspectral instruments for differentiating conifer stands of varying Ca availability, we used a Visible/Infrared Intelligent Spectrometer to measure reflectance spectra of fresh red spruce needles from trees at both Ca-amended and reference sites. Needles from Ca-amended sites were characterized by higher percent reflectance of incident radiation. Differences in spectral indices of needle health were apparent mostly in mixed-needle-year boughs (MNY), as opposed to current-year (CY), or third-year (3Y) needle classes. The Ca-amended spectra of MNY boughs had an average green peak of 7.32 ± 0.29 percent, while reference samples had a green peak of 6.37 ± 0.20 percent. The Red-edge Inflection Point (REIP) of MNY boughs was lower in Ca-amended than in reference treatments, occurring at 725.7 ± 0.7 nm and 727.3 ± 0.6 nm, respectively. The ratio of simulated Landsat band measurements (TM 5/4) of Ca-treated MNY needles was 0.440 ± 0.007, while that of reference was 0.421 ± 0.008.

  3. Observations of oceanic crust and mantle structures at a deep ocean seismic array in the Eastern Mid Atlantic

    NASA Astrophysics Data System (ADS)

    Hannemann, Katrin; Krüger, Frank; Dahm, Torsten

    2016-04-01

    In 2011, twelve ocean bottom stations (OBS) were installed approximately 100 km North of the Gloria Fault during the DOCTAR project (Deep OCean Test ARray). This fault marks the plate boundary between the Eurasian and African plate in the North Eastern Mid Atlantic. The experiment took place in water depth of 4-6 km, 800 km West of the Portuguese coast. The stations were equipped with broad band seismometers which recorded for ten months. We employ P and S receiver functions (RF) to have a closer look at the structure of crust and mantle. The ocean is a quite noisy environment, therefore the number of usable events is low (around 20) compared to RF studies on land. We use several quality criteria (e.g. signal to noise ratio, relative spike position) to select proper processing parameters for the calculation of the RF and carefully reviewed all later on used RF. Despite the low number of events, the usage of an array of OBS with an aperture of 75 km allows us to investigate deeper discontinuities (e.g. in 410 and 660 km depth) compared to single station approaches which are usually employed for OBS. Furthermore, we increase the number of usable events by applying array methods. We use move out corrected and stacked RF to have a closer look at the mantle transition zone, and estimate average depth values for the Moho, the lithosphere asthenosphere boundary (LAB) and the base of the asthenosphere. The Moho lies at depth of 7 km, the LAB at approximately 50 km and the asthenosphere has an approximated thickness of 110 km. We observe a slight increase in the time difference of the mantle discontinuity conversion times compared to PREM. RF give just information regarding the impedance contrast at a discontinuity instead of velocities. We additionally use P wave polarization of teleseismic events to estimate absolute S velocities beneath the single stations. All in all, we use the information gained by the RF analysis, and the analysis of the P wave polarization to

  4. Integrated well log and 2-D seismic data interpretation to image the subsurface stratigraphy and structure in north-eastern Bornu (Chad) basin

    NASA Astrophysics Data System (ADS)

    Isyaku, Aminu A.; Rust, Derek; Teeuw, Richard; Whitworth, Malcolm

    2016-09-01

    Structural and stratigraphic mapping within the Bornu Basin in north east Nigeria was commonly carried out using traditional field geological methods. However, such traditional approaches remain inadequate in the semi-arid region characterised by topographically flat areas and lack of continuous bedrock outcrops that are mostly concealed beneath sand cover. Previous studies in the north-eastern part of the basin carried out using ditch cuttings from few wells and disconnected seismic data were largely inadequate and the resulting stratigraphic analyses were more often generalised. This paper presents an integrated structural and stratigraphic study of the basin using combined subsurface geophysical datasets. A Combined Log Pattern (CLP) method is a well log analysis, which utilises various well log data including gamma ray, resistivity, bulk density and sonic logs to identify lithology and stratigraphic boundaries of subsurface formations. This method is applied to constrain the subsurface stratigraphy of the north-eastern part of the Bornu Basin bordering the Lake Chad. In addition to qualitative combined well log analysis, the time-depth relationship of the sonic log and seismic data was quantitatively determined by tying a well with an intersecting seismic section to validate the stratigraphic facies horizons identified. Four well log facies and their environments of deposition were characterised from the combined well log analysis of the different log types. It is discovered that the Cretaceous basement structural features controlled the deposition of overlying formations in the basin. Without intact core data, the shallower wells were discovered to have bottomed over subsurface horst features while deeper wells penetrated into the basal facies contained mainly within the grabens. Main subsurface structural lineaments in the area include NW-SE, NE-SW and NNW-SSE trending faults, which mainly formed the horst and graben features. Some stratigraphic formations

  5. Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abdeen, Mamdouh M.; Greiling, Reinhard O.; Sadek, Mohamed F.; Hamad, Sayed S.

    2014-11-01

    In order to assess the Pan-African structural evolution from early orogenic fabrics through Najd wrenching to the latest orogenic collapse/extension, the authors used field work, aided by aerial photographs and satellite images. This work is complemented by the study of the anisotropy of the magnetic susceptibility (AMS, or magnetic fabric). The Pan-African rock associations of the Um Gheig-Kadabora area can be divided into a lower tier composed mainly of amphibolite-migmatite and granitoid gneisses, and an upper tier of ophiolitic rocks, metavolcanics and their related volcaniclastics, and molasse-type Hammamat sediments. Both these units are intruded by late orogenic granitoid plutons and dykes. The lower tier is exposed in a domal structure in the El Sibai area, the upper tier forms a series of weakly to highly deformed thrust units, called Pan-African Nappes here, which are dissected by high strain shear zones. According to their age, these rock units are divided here into early and late-orogenic. The early orogenic rock association is characterized by medium-high metamorphic grades. The late orogenic rock association is characterized by low metamorphic grade. The rocks in the upper tier form a series of low angle thrust sheets, which are bounded by NW-striking high angle shear zones related to the Najd Fault System. The early orogenic rocks show a polyphase structural evolution with early folds, thrusts, and strike-slip shear zones. The late orogenic rocks show a relatively weaker deformation. The latest intrusives studied here are the dykes dissecting the late orogenic Kadabora granite. In the present work magnetic fabric data document the deformational features in detail and assess the role of the Najd Fault System in the deformational evolution. A strong variation in volume susceptibility of various rocks, due to their variations in mineral composition, is observed. Lower values are in the range of 10-6 SI units for late-orogenic alkaline granite and the

  6. Population structure and gene flow of the Atlantic walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation.

    PubMed

    Andersen, L W; Born, E W; Gjertz, I; Wiig, O; Holm, L E; Bendixen, C

    1998-10-01

    The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow (Nm) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land-Svalbard population, which were connected by moderate gene flow.

  7. Effects of tsaoko (Fructus tsaoko) cultivating on tree diversity and canopy structure in the habitats of eastern hoolock gibbon (Hoolock leuconedys)

    PubMed Central

    Sheng-Dong, YUAN; Han-Lan, FEI; Shao-Han, ZHU; Liang-Wei, CUI; Huai-Sen, AI; Peng-Fei, FAN

    2014-01-01

    In this study, the quadrat method was used to study the effects of tsaoko (Fructus tsaoko) plantation on tree diversity and canopy structure of two natural habitats of eastern hoolock gibbon (Hoolock leuconedys): Nankang (characterized by extensive tsaoko plantation) and Banchang (relatively well reserved and without tsaoko plantation). Totally, 102 tree species from 25 families and 16 woody liana species from 10 families were recorded in Nankang, whereas 108 tree species from 30 families and 17 woody liana species from 12 families were recorded in Banchang. Although the tree species between two habitats is different, both habitats are characterized by enriched food resources for eastern hoolock gibbons, sharing similar dominant plant families. Due to tsaoko plantation, tree density proportion and diversity of forest layerⅠ (>20 m) in Nankang were both significantly decreased, but the tree density of layerⅡ (10−20 m) increased. Likewise, in conjunction with these behavioral observations, we also address potential impacts of tsaoko plantation on the behavior of eastern hoolock gibbon. PMID:24866494

  8. Effects of tsaoko (Fructus tsaoko) cultivating on tree diversity and canopy structure in the habitats of eastern hoolock gibbon (Hoolock leuconedys).

    PubMed

    Yuan, Sheng-Dong; Fei, Han-Lan; Zhu, Shao-Han; Cui, Liang-Wei; Ai, Huai-Sen; Fan, Peng-Fei

    2014-05-01

    In this study, the quadrat method was used to study the effects of tsaoko (Fructus tsaoko) plantation on tree diversity and canopy structure of two natural habitats of eastern hoolock gibbon (Hoolock leuconedys): Nankang (characterized by extensive tsaoko plantation) and Banchang (relatively well reserved and without tsaoko plantation). Totally, 102 tree species from 25 families and 16 woody liana species from 10 families were recorded in Nankang, whereas 108 tree species from 30 families and 17 woody liana species from 12 families were recorded in Banchang. Although the tree species between two habitats is different, both habitats are characterized by enriched food resources for eastern hoolock gibbons, sharing similar dominant plant families. Due to tsaoko plantation, tree density proportion and diversity of forest layerⅠ (>20 m) in Nankang were both significantly decreased, but the tree density of layerⅡ (10-20 m) increased. Likewise, in conjunction with these behavioral observations, we also address potential impacts of tsaoko plantation on the behavior of eastern hoolock gibbon.

  9. Eastern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this SeaWiFS image of eastern Alaska, the Aleutian Islands, Kodiak Island, Yukon and Tanana rivers are clearly visible. Also visible, but slightly hidden beneath the clouds, is a bloom in Bristol Bay. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  10. Structural evolution and Cenozoic tectonostratigraphy of the Cairo-Suez district, north Eastern Desert of Egypt: Field-structural data from Gebel Qattamiya-Gebel Um Reheiat area

    NASA Astrophysics Data System (ADS)

    Hagag, Wael

    2016-06-01

    Detailed field mapping reveals that continental rifting is strongly deforming the Gebel Qattamiya-Gebel Um Reheiat area and the entire Cairo-Suez district, in north Eastern Desert of Egypt. Rift-related structures are predominantly represented by E to WNW, NNW and NW oriented faults. The E to WNW oriented faults are small and build up the Gebel Qattamiya en echelon fault belt, whereas the faults trending NNW and NW establish a pervasive horst and graben structural style involving some rhomb-shape horsts as Gebel Qattamiya (GQRH), Gebel Um Reheiat (GURRH) and south Gebel Um Reheiat (SGURRH). Rock units of the Eocene succession and Oligocene sediments are well exposed and highly controlled by rift-related structures. Rifting was developed through two rift-phases; initial and major ones. The initial phase (a newly recognized phase in this contribution) has been occurred in Late Eocene (Priabonian), while the main phase was prevailing during Late Oligocene-Early Miocene time and is characterized by hydrothermal veins and basaltic eruptions. Continental transtension in the Cairo-Suez district, including the study area, was probably synchronous with a major tectonic stage (Pyrenean-Atlasic movement) of continental collision between African-Arabian and Eurasian plates in Late Eocene-Oligocene time. Field investigation suggests that the transfer of displacement (slip) from the Gulf of Suez proto-rift into the E-W oriented faults ''relays'' is an important mechanism, which helps to explain the current structural framework and tectonic evolution of the Cairo-Suez district. Reactivation of such faults with right-lateral divergent wrenching with NE-SW oriented extension deformed the Cairo-Suez district with several E-W oriented en echelon fault belts (e.g. Gebel Qattamiya fault belt in the study area). Thus the Cairo-Suez district represents an accommodation or transfer zone in northeastern Egypt, intercepting the ''far-field stresses'' from the Arabian-Nubian Shield, the Red

  11. A high-density genetic linkage map of a black spruce (Picea mariana) × red spruce (Picea rubens) interspecific hybrid.

    PubMed

    Kang, Bum-Yong; Major, John E; Rajora, Om P

    2011-02-01

    Genetic maps provide an important genomic resource of basic and applied significance. Spruce (Picea) has a very large genome size (between 0.85 × 1010 and 2.4 × 1010 bp; 8.5-24.0 pg/1C, a mean of 17.7 pg/1C ). We have constructed a near-saturated genetic linkage map for an interspecific backcross (BC1) hybrid of black spruce (BS; Picea mariana (Mill.) B.S.P.) and red spruce (RS; Picea rubens Sarg.), using selectively amplified microsatellite polymorphic loci (SAMPL) markers. A total of 2284 SAMPL markers were resolved using 31 SAMPL-MseI selective nucleotide primer combinations. Of these, 1216 SAMPL markers showing Mendelian segregation were mapped, whereas 1068 (46.8%) SAMPL fragments showed segregation distortion at α = 0.05. Maternal, paternal, and consensus maps consistently coalesced into 12 linkage groups, corresponding to the haploid chromosome number (1n = 1x = 12) of 12 in the genus Picea. The maternal BS map consisted of 814 markers distributed over 12 linkage groups, covering 1670 cM, with a mean map distance of 2.1 cM between adjacent markers. The paternal BS × RS map consisted of 773 markers distributed over 12 linkage groups, covering 1563 cM, with a mean map distance of 2.0 cM between adjacent markers. The consensus interspecific hybrid BC1 map consisted of 1216 markers distributed over 12 linkage groups, covering 1865 cM (98% genome coverage), with a mean map distance of 1.5 cM between adjacent markers. The genetic map reported here provides an important genomic resource in Picea, Pinaceae, and conifers.

  12. Inducibility of chemical defenses in Norway spruce bark is correlated with unsuccessful mass attacks by the spruce bark beetle.

    PubMed

    Schiebe, Christian; Hammerbacher, Almuth; Birgersson, Göran; Witzell, Johanna; Brodelius, Peter E; Gershenzon, Jonathan; Hansson, Bill S; Krokene, Paal; Schlyter, Fredrik

    2012-09-01

    Secondary attraction to aggregation pheromones plays a central role in the host colonization behavior of the European spruce bark beetle Ips typographus. However, it is largely unknown how the beetles pioneering an attack locate suitable host trees, and eventually accept or reject them. To find possible biomarkers for host choice by I. typographus, we analyzed the chemistry of 58 Norway spruce (Picea abies) trees that were subsequently either (1) successfully attacked and killed, (2) unsuccessfully attacked, or (3) left unattacked. The trees were sampled before the main beetle flight in a natural Norway spruce-dominated forest. No pheromones were used to attract beetles to the experimental trees. To test the trees' defense potential, each tree was treated in a local area with the defense hormone methyl jasmonate (MeJ), and treated and untreated bark were analyzed for 66 different compounds, including terpenes, phenolics and alkaloids. The chemistry of MeJ-treated bark correlated strongly with the success of I. typographus attack, revealing major chemical differences between killed trees and unsuccessfully attacked trees. Surviving trees produced significantly higher amounts of most of the 39 analyzed mono-, sesqui-, and diterpenes and of 4 of 20 phenolics. Alkaloids showed no clear pattern. Differences in untreated bark were less pronounced, where only 1,8-cineole and (-)-limonene were significantly higher in unsuccessfully attacked trees. Our results show that the potential of individual P. abies trees for inducing defense compounds upon I. typographus attack may partly determine tree resistance to this bark beetle by inhibiting its mass attack.

  13. Stratigraphy, structure and regional correlation of eastern Blue Ridge sequences in southern Virginia and northwestern North Carolina: an interim report from new USGS mapping

    USGS Publications Warehouse

    Carter, Mark W.; Merschat, Arthur J.

    2014-01-01

    The contact between eastern Blue Ridge stratified rocks above Mesoproterozoic basement rocks is mostly faulted (Gossan Lead and Red Valley). The Callaway fault juxtaposes Ashe and Lynchburg rocks above Wills Ridge Formation. Alligator Back Formation rocks overlie Ashe and Lynchburg rocks along the Rock Castle Creek fault, which juxtaposes rocks of different metamorphism. The fault separates major structural domains: rocks with one penetrative foliation in the footwall, and pin-striped recrystallized compositional layering, superposed penetrative foliations, and cleavage characterize the hanging wall. These relationships are ambiguous along strike to the southwest, where the Ashe and Alligator Back formations are recrystallized at higher metamorphic grades.

  14. Functional profile of black spruce wetlands in Alaska

    SciTech Connect

    Post, R.A.

    1996-09-01

    The profile describes the ecologic context and wetland functions of black spruce (Picea mariana) wetlands (BSWs) covering about 14 million ha of Alaska taiga. Ecologic descriptions include climate, permafrost, landforms, post-Pleistocene vegetation, fire, successional processes, black spruce community types and adaptations, and characteristics of BSWs. The profile describes human activities potentially affecting BSWs and identifies research literature and data gaps generally applicable to BSWs. Hydrologic, water quality, global biogeochemical, and ecologic functions of BSWs, as well as their socioeconomic uses, appear in the profile, along with potential functional indicators, expected sensitivities of functions to fill placement or weltand drainage, and potential mitigation strategies for impacts. Functional analysis separately considers ombrotrophic and minerotrophic BSWs where appropriate. Depending on trophic status, Alaska`s BSWs perform several low-magnitude hydrologic (groundwater discharge and recharge, flow regulation, and erosion control) and ecologic (nutrient export, nutrient cycling, and food-chain support) functions and several substantial water quality (sediment retention, nutrient transformation, nutrient uptake, and contaminant removal), global biogeochemical (carbon cycling and storage), and ecologic (avian and mammalian habitat) functions. BSWs also provide important socioeconomic uses: harvested of wetland-dependent fish, wildlife, and plant resources and active winter recreation.

  15. Dissolution of beech and spruce milled woods in LiCl/DMSO.

    PubMed

    Wang, Zhiguo; Yokoyama, Tomoya; Chang, Hou-Min; Matsumoto, Yuji

    2009-07-22

    A novel solvent system, lithium chloride/dimethyl sulfoxide (LiCl/DMSO), was developed for dissolving milled wood. This system completely dissolved beech and spruce milled woods prepared from the Wiley woods (coarse wood meals prepared by a Wiley mill) by 2 h planetary ball-milling under the milling conditions employed. The dependence of the structural change of lignin on the degree of milling was examined to evaluate the correlation between the dissolution and lignin structure. The nitrobenzene oxidation analyses showed that the 2 h milling caused almost no structural change in the aromatic part of lignin in the milled woods. The ozonation analyses suggested that the decrease of the erythro ratio [erythro/(erythro + threo)] obtained from beta-O-4 structure in lignin is only 0.35% after the 2 h milling. Although the yield decrease of the ozonation products was 9.8% after the 2 h milling, this value was fairly smaller than that after a longer time milling. When it is taken into consideration that the other solvent systems for dissolution of wood meal, which are proposed by Lu and Ralph, require 5 h of milling under the same milling conditions to dissolve the milled woods, it is safely stated that the LiCl/DMSO solvent system completely dissolves milled wood, the lignin of which is structurally less altered and, thus, is expected to provide an improved method for structural analysis of the entire lignin fraction in wood cell wall.

  16. Water masses, ocean fronts, and the structure of Antarctic seabird communities: Putting the eastern Bellingshausen Sea in perspective

    NASA Astrophysics Data System (ADS)

    Ribic, Christine A.; Ainley, David G.; Glenn Ford, R.; Fraser, William R.; Tynan, Cynthia T.; Woehler, Eric J.

    2011-07-01

    Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April-September) and summer (October-March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Adélie penguins ( Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group dominated

  17. Water masses, ocean fronts, and the structure of Antarctic seabird communities: putting the eastern Bellingshausen Sea in perspective

    USGS Publications Warehouse

    Ribic, Christine A.; Ainley, David G.; Ford, R. Glenn; Fraser, William R.; Tynan, Cynthia T.; Woehler, Eric J.

    2015-01-01

    Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April–September) and summer (October–March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Adélie penguins (Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group

  18. FAST TRACK COMMUNICATION: Growth melt asymmetry in ice crystals under the influence of spruce budworm antifreeze protein

    NASA Astrophysics Data System (ADS)

    Pertaya, Natalya; Celik, Yeliz; Di Prinzio, Carlos L.; Wettlaufer, J. S.; Davies, Peter L.; Braslavsky, Ido

    2007-10-01

    Here we describe studies of the crystallization behavior of ice in an aqueous solution of spruce budworm antifreeze protein (sbwAFP) at atmospheric pressure. SbwAFP is an ice binding protein with high thermal hysteresis activity, which helps protect Choristoneura fumiferana (spruce budworm) larvae from freezing as they overwinter in the spruce and fir forests of the north eastern United States and Canada. Different types of ice binding proteins have been found in many other species. They have a wide range of applications in cryomedicine and cryopreservation, as well as the potential to protect plants and vegetables from frost damage through genetic engineering. However, there is much to learn regarding the mechanism of action of ice binding proteins. In our experiments, a solution containing sbwAFP was rapidly frozen and then melted back, thereby allowing us to produce small single crystals. These maintained their hexagonal shapes during cooling within the thermal hysteresis gap. Melt-growth-melt sequences in low concentrations of sbwAFP reveal the same shape transitions as are found in pure ice crystals at low temperature (-22 °C) and high pressure (2000 bar) (Cahoon et al 2006 Phys. Rev. Lett. 96 255502) while both growth and melt shapes display faceted hexagonal morphology, they are rotated 30° relative to one another. Moreover, the initial melt shape and orientation is recovered in the sequence. To visualize the binding of sbwAFP to ice, we labeled the antifreeze protein with enhanced green fluorescent protein (eGFP) and observed the sbwAFP-GFP molecules directly on ice crystals using confocal microscopy. When cooling the ice crystals, facets form on the six primary prism planes (slowest growing planes) that are evenly decorated with sbwAFP-GFP. During melting, apparent facets form on secondary prism planes (fastest melting planes), leaving residual sbwAFP at the six corners of the hexagon. Thus, the same general growth-melt behavior of an apparently rotated

  19. New structural and seismological evidence and interpretation of a lithospheric-scale shear zone at the southern edge of the Ionian subduction system (central-eastern Sicily, Italy)

    NASA Astrophysics Data System (ADS)

    Barreca, G.; Scarfı, L.; Cannavò, F.; Koulakov, I.; Monaco, C.

    2016-06-01

    Geological, gravimetric, and seismological data from the central-eastern Sicily (Italy) provide evidences of a NW-SE oriented shear zone at the southern edge of the Ionian subduction system. This structure consists of a near 100 km long lithospheric-scale structural and seismic boundary. In the near-surface, it shows Plio-Pleistocene vertical-axis structural rotations, kilometer-scale topographic imprint, progressive wrenching, and large down-faulting. All these features, together with its location south-west of the subduction system, allow us to interpret the shear zone as the upper plate expression of an abandoned Subduction Transform Edge Propagator fault, working before slab detachment, currently reactivated by elastic rebound or mantle upwelling mechanism triggered by slab detachment, to form an incipient transform belt separating compartments characterized by different motion in the modern context of Africa-Europe convergence.

  20. Velocity structure from forward modeling of the eastern ridge-transform intersection area of the Clipperton Fracture Zone, East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Begnaud, Michael L.; McClain, James S.; Barth, Ginger A.; Orcutt, John A.; Harding, Alistair J.

    1997-04-01

    In the spring of 1994, we undertook an extensive geophysical study of the Clipperton Fracture Zone (FZ) on the fast spreading East Pacific Rise. The Clipperton Area Seismic Study to Investigate Compensation experiment (CLASSIC) included surveys to examine the deep structures associated with the fracture zone and adjacent northern ridge segment. In this paper, we report the results from five seismic profiles acquired over the eastern ridge-transform intersection (RTI), including profiles over the RTI high, the northern ridge segment, and the eastern transform region. The travel time data for crustal phases, Moho reflections, and mantle phases were modeled using two-dimensional ray tracing. Seismic profiles reveal that the crust is similar in thickness north and south of the Clipperton FZ, despite differences in axial topography that have previously been interpreted in terms of differences in magma supply. When compared to older crust, the northern ridge axis is characterized by lower seismic velocities and higher attenuation. In our model, a low-velocity zone exists beneath the ridge axis, probably associated with a zone of partial melt and/or very high temperatures. Within the transform zone, we find that the southeastern trough is underlain by nearly normal crustal structure. The crust is slightly thinner than the adjacent aseismic extension but not enough to compensate for the depths of the trough. Toward the RTI, the trough is replaced by an intersection high which appears underlain by a thickened crust, and a thicker upper crustal section. Both characteristics indicate that the intersection high is a volcanic feature produced by excess volcanism at the intersection. The volcanism acts to "fill in" the transform trough, creating the thicker crust that extends under the eastern aseismic extension of the transform. Our results show that the northern ridge segment, often identified as magma-starved, displays the crustal thickness and apparent signal attenuation

  1. Sperm whale population structure in the eastern and central North Pacific inferred by the use of single-nucleotide polymorphisms, microsatellites and mitochondrial DNA.

    PubMed

    Mesnick, Sarah L; Taylor, Barbara L; Archer, Frederick I; Martien, Karen K; Treviño, Sergio Escorza; Hancock-Hanser, Brittany L; Moreno Medina, Sandra Carolina; Pease, Victoria L; Robertson, Kelly M; Straley, Janice M; Baird, Robin W; Calambokidis, John; Schorr, Gregory S; Wade, Paul; Burkanov, Vladimir; Lunsford, Chris R; Rendell, Luke; Morin, Phillip A

    2011-03-01

    We use mitochondrial DNA (mtDNA) (400 bp), six microsatellites and 36 single-nucleotide polymorphisms (SNPs), 20 of which were linked, to investigate population structure of sperm whales (Physeter macrocephalus) in the eastern and central North Pacific. SNP markers, reproducible across technologies and laboratories, are ideal for long-term studies of globally distributed species such as sperm whales, a species of conservation concern because of both historical and contemporary impacts. We estimate genetic differentiation among three strata in the temperate to tropical waters where females are found: California Current, Hawai`i and the eastern tropical Pacific. We then consider how males on sub-Arctic foraging grounds assign to these strata. The California Current stratum was differentiated from both the other strata (P < 0.05) for mtDNA, microsatellites and SNPs, suggesting that the region supports a demographically independent population and providing the first indication that males may exhibit reproductive philopatry. Comparisons between the Hawai`i stratum and the eastern tropical Pacific stratum are not conclusive at this time. Comparisons with Alaska males were statistically significant, or nearly so, from all three strata and individuals showed mixed assignment to, and few exclusions from, the three potential source strata, suggesting widespread origin of males on sub-Arctic feeding grounds. We show that SNPs have sufficient power to detect population structure even when genetic differentiation is low. There is a need for better analytical methods for SNPs, especially when linked SNPs are used, but SNPs appear to be a valuable marker for long-term studies of globally dispersed and highly mobile species.

  2. Crust Uppermost Mantle Structure beneath Eastern Asia: Progress towards a Uniform, Tightly Constrained, High Resolution 3-D Model

    NASA Astrophysics Data System (ADS)

    Shen, W.; Ritzwoller, M. H.; Zheng, Y.; Lin, F. C.; Kim, Y.; Ning, J.; Kang, D.; Feng, L.; Wiens, D. A.

    2015-12-01

    In the past decade, large and dense seismic arrays have been deployed across much of eastern Asia (e.g., the "CEArray" and the "China Array" deployed by the China Earthquake Administration (CEA), the NECESS Array deployed collaboratively by China, Japan and the US, Korean Seismic Network, KNET and other networks in Japan, and historical PASSCAL installations), which have been used to produce increasingly well resolved models of the crust and uppermost mantle at different length scales. These models, however, do not cover eastern Asia uniformly. In this presentation, we report on an effort to generate a uniform high resolution 3-D model of the crust and uppermost mantle beneath eastern Asia using state-of-art surface wave and body wave inversion techniques. Highlights of this effort include: 1) We collect ambient noise cross-correlations using more than 1,800 seismic stations from multiple seismic arrays in this area and perform uniform surface wave tomography for the study area. 2) We collect P-wave receiver functions for over 1,000 stations and Rayleigh wave H/V ratio measurements for over 200 stations in this area. 3) We adopt a Bayesian Monte Carlo inversion to the Rayleigh wave dispersion maps and produce a uniform 3-D model with uncertainties of the crust and uppermost mantle. 4) In the areas where receiver functions and/or Rayleigh wave H/V ratios are collected, we replace the surface wave inversion by a joint inversion of surface waves and these seismic observables. The resulting model displays a great variety and considerable richness of geological and tectonic features in the crust and in the uppermost mantle which we summarize and discuss with focus on the relationship between the observed crustal variations and tectonic/geological boundaries and lithospheric modifications associated with volcanism in Northeast China.

  3. Combined structural interventions for gender equality and livelihood security: a critical review of the evidence from southern and eastern Africa and the implications for young people

    PubMed Central

    Gibbs, Andrew; Willan, Samantha; Misselhorn, Alison; Mangoma, Jaqualine

    2012-01-01

    Background Young people in southern and eastern Africa remain disproportionately vulnerable to HIV with gender inequalities and livelihood insecurities being key drivers of this. Behavioural HIV prevention interventions have had weak outcomes and a new generation of structural interventions have emerged seeking to challenge the wider drivers of the HIV epidemic, including gender inequalities and livelihood insecurities. Methods We searched key academic data bases to identify interventions that simultaneously sought to strengthen people's livelihoods and transform gender relationships that had been evaluated in southern and eastern Africa. Our initial search identified 468 articles. We manually reviewed these and identified nine interventions that met our criteria for inclusion. Results We clustered the nine interventions into three groups: microfinance and gender empowerment interventions; supporting greater participation of women and girls in primary and secondary education; and gender empowerment and financial literacy interventions. We summarise the strengths and limitations of these interventions, with a particular focus on what lessons may be learnt for young people (18–24). Conclusions Our review identified three major lessons for structural interventions that sought to transform gender relationships and strengthen livelihoods: 1) interventions have a narrow conceptualisation of livelihoods, 2) there is limited involvement of men and boys in such interventions, 3) studies have typically been done in stable populations. We discuss what this means for future interventions that target young people through these methods. PMID:22713350

  4. Structures controlling U and Th mineralisation in the Gebel Felat area of the south Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Kamel, Ahmed Farouk

    1997-05-01

    In the Eastern Desert of Egypt, younger granites host U and Th mineralisations which are concentrated along faults and joints. In particular, the Gebel Felat Pluton is characterised by a high level of radioactivity as shown by an aeroradiometric survey. The U content is 82 ppm and the Th content is 15 ppm in areas of high radioactivity. The rocks are cross-cut by two main sets of fractures trending east-west and northwest-southeast. The contour maps of these two trends can be correlated with the aeroradiometric map of the same area.

  5. Genetic structure of the date palm (Phoenix dactylifera) in the Old World reveals a strong differentiation between eastern and western populations

    PubMed Central

    Zehdi-Azouzi, Salwa; Cherif, Emira; Moussouni, Souhila; Gros-Balthazard, Muriel; Abbas Naqvi, Summar; Ludeña, Bertha; Castillo, Karina; Chabrillange, Nathalie; Bouguedoura, Nadia; Bennaceur, Malika; Si-Dehbi, Farida; Abdoulkader, Sabira; Daher, Abdourahman; Terral, Jean-Frederic; Santoni, Sylvain; Ballardini, Marco; Mercuri, Antonio; Ben Salah, Mohamed; Kadri, Karim; Othmani, Ahmed; Littardi, Claudio; Salhi-Hannachi, Amel; Pintaud, Jean-Christophe; Aberlenc-Bertossi, Frédérique

    2015-01-01

    Background and Aims Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecological value to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information on global genetic diversity and population structure. In order to contribute to the varietal improvement of date palms and to provide new insights on the influence of geographic origins and human activity on the genetic structure of the date palm, this study analysed the diversity of the species. Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat (SSR) markers and a plastid minisatellite. Key Results Using a Bayesian clustering approach, the date palm genotypes can be structured into two different gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second, termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also noted, which points at gene flows between eastern and western origins, mostly from east to west, following a human-mediated diffusion of the species. Conclusions This study assesses the distribution and level of genetic diversity of accessible date palm resources, provides new insights on the geographic origins and genetic history of the cultivated component of this species, and confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each gene pool. PMID

  6. Can we trace the eastern Gondwanan margin in Australia? New perspectives from transdimensional inversion of ambient noise for 3D shear velocity structure

    NASA Astrophysics Data System (ADS)

    Pilia, S.; Rawlinson, N.; Direen, N. G.

    2013-12-01

    Although the notion of Rodinia is quite well accepted in the geoscience community, the location and nature of the eastern continental margin of the Gondwana fragment in Australia is still vague and remains one of the most hotly debated topics in Australian geology. Moreover, most post-Rodinian reconstructions models choose not to tackle the ';Tasmanian challenge', and focus only on the tectonic evolution of mainland southeast Australia, thereby conveniently ignoring the wider tectonic implications of Tasmania's complex geological history. One of the chief limitations of the tectonic reconstructions in this region is a lack of information on Paleozoic (possibly Proterozoic) basement structures. Vast Mesozoic-Cainozoic sedimentary and volcanic cover sequences obscure older outcrops and limit the power of direct observational techniques. In response to these challenges, our effort is focused on ambient seismic noise for imaging 3D crustal shear velocity structure using surface waves, which is capable of illuminating basement structure beneath younger cover. The data used in this study is sourced from the WOMBAT transportable seismic array, which is compounded by around 650 stations spanning the majority of southeastern Australia, including Tasmania and several islands in Bass Strait. To produce the highest quality Green's functions, careful processing of the data has been performed, after which group velocity dispersion measurements have been carried out using a frequency-time analysis method on the symmetric component of the empirical Green's functions (EGFs). Group dispersion measurements from the EGFs have been inverted using a novel hierarchical, transdimensional, Bayesian algorithm to obtain Rayleigh-wave group velocity maps at different periods from 2 to 30 s. The new approach has several advantages in that the number and distribution of model parameters are implicitly controlled by the data, in which the noise is treated as unknown in the inversion. This

  7. Stilbene biosynthesis in the needles of spruce Picea jezoensis.

    PubMed

    Kiselev, K V; Grigorchuk, V P; Ogneva, Z V; Suprun, A R; Dubrovina, A S

    2016-11-01

    Stilbenes are valuable phenolic compounds that are synthesized in plants via the phenylpropanoid pathway where stilbene synthase (STS) directly catalyzes resveratrol or pinosylvin formation. Currently, there is a lack of information about the stilbene biosynthetic pathway in spruce (Picea). Resveratrol and piceatannol derivatives have been detected in the spruce bark, needles, and roots. We analyzed seasonal variation in stilbene spectrum and content in the needles of different ages of one tree of spruce Picea jezoensis. HPLC analysis revealed the presence of nine stilbenes: t- and cis-astringin, t- and cis-piceid, t- and cis-isorhapontin, and t-piceatannol were present in amounts of 0.01-6.07 mg/g of dry weight (DW), while t-isorhapontigenin and t-resveratrol were present in traces (0.001-0.312 μg/g DW). T-astringin prevailed over other stilbenoid compounds (66-86% of all stilbenes). The highest total stilbene content was detected in one-year-old needles collected in the autumn and spring (5.4-7.77 mg/g DW). We previously cloned and sequenced full-length cDNAs of the four STS transcripts (PjSTS1a, PjSTS1b, PjSTS2, and PjSTS3) of P. jezoensis. This study presents a detailed analysis of seasonal variations in PjSTS1a, 1b, 2, and 3 transcript levels in the needles of P. jezoensis of different ages using qRT-PCR. PjSTS1a and PjSTS1b transcription was higher in the needles collected in the autumn, spring, or summer than in the winter. PjSTS2 was actively transcribed in the needles of all ages collected in the winter, spring, and summer. PjSTS3 expression did not significantly change during the year and did not depend on the age of the needles. Therefore, the data show that high levels of the stilbene glucosides and PjSTS expression are present in the needles of P. jezoensis.

  8. Monoterpene emissions from Scots pine and Norwegian spruce

    SciTech Connect

    Janson, R.W. )

    1993-02-20

    Rates of monoterpene emissions from Scots pine (Pinus sylvestris) and Norwegian spruce (Picea abies) have been measured at four sites in Sweden with a dynamic flow chamber technique. Forest floor emissions have been made in the pine forest with the static chamber technique. The compounds [Delta][sup 3]-carene and [alpha]-pinene were the predominant terpenes emitted from the crown and floor of the Scots pine forest. Alpha-pinene was the main terpene emitted from Norwegian spruce at the sites in southern and central Sweden, while [Delta][sup 3]-carene was predominant at the northern site. Emission rates, normalized to temperature, were seen to vary diurnally with a maximum at midday, and seasonally with maxima in early May and October, and a summer maximum in June-July. The possible dependence of the emission rate on needle growth rate and other plant-physiological processes is discussed. A higher emission rate and different relative composition of the emission was seen to occur when the vegetation was wet, as compared to dry vegetation. The emission from the pine forest floor was seen to have a composition different from that of the crown and a seasonality of the rate similar to that of the crown. The ground emission could not be explained by sources in the litter or ground vegetation alone, and it is suggested that the root system of the trees is also an emission source. The emission rate from the pine forest floor was of the order of 30% of the crown emission. The July rate of emission from the crown of Scots pine, normalized to 20[degrees]C and averaged over four sites in Sweden, was 0.8 [plus minus] 0.4 [mu]g (gdw (grams dry weight) h)[sup [minus]1], and for Norwegian spruce, 0.5 [plus minus] 0.7 [mu]g(gdw h)[sup [minus]1]. It would seem that previous regional and global estimates of hydrocarbon fluxes to the atmosphere have used emission factors which are too high for boreal coniferous forests. 52 refs., 8 figs., 9 tabs.

  9. Black Carbon characterization in Quebec black spruce forests

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, L. N.; Wasylishen, R. E.; MacKenzie, M. D.; Quideau, S. A.

    2012-04-01

    Black carbon (BC), the solid carbonaceous residue of incomplete combustion, is a major by-product of wildfires in Quebec black spruce forests. Because of its estimated recalcitrance, it is considered a valuable pool in the global carbon cycle. However, BC characteristics, and more specifically its resistance to degradation depend on its conditions of formation. The objective of this study was to characterize BC chemical and physical properties under varying fire severities in order to assess its potential for recalcitrance as a passive carbon pool. Fresh BC samples from the forest floor were collected in 2010 from Quebec black spruce forests stands that had burnt 3-5 years prior. Fire severity was assessed at each sampling location and a total of 33 samples were selected to cover the range of severity encountered in these burnt forests. Samples were further analyzed for aromaticity and porosity using elemental and proximate analyses, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM) and surface area (SA) analysis. They were then compared to BC samples produced under controlled conditions in the laboratory (lab-BC). The 13C NMR spectra of the BC collected on low fire severity sites showed a distribution of total intensity between the different spectral regions very similar to those of unburnt fuels. They were generally dominated by a peak at 74 ppm indicative of cellulose. On the other hand, 13C NMR spectra obtained for BC from high fire severity sites were dominated by peaks from aromatic carbons. When compared to the lab-BC NMR spectra, we concluded that the temperature of formation for the 33 analyzed samples ranged between 75°C and 250°C and that pyrolysis conditions prevailed, which points towards BC formation by a smouldering fire. Atomic ratio values (H/C = [1.36-0.77]; O/C = [0.75-0.30]) decreased with increasing fire severity and were in agreement with the results from 13C NMR spectroscopy. Finally, the

  10. Seasonal variation of BVOC emissions from Norway spruce

    NASA Astrophysics Data System (ADS)

    Wang, Min; Schurgers, Guy; Ekberg, Anna; Arneth, Almut; Holst, Thomas

    2015-04-01

    Biogenic volatile organic compounds (BVOCs) are known as a source of secondary organic aerosols (SOA) due to their high reactivity in the atmosphere [1, 2]. Dominant boreal forest species (pine, spruce and birch) have been considered to be high monoterpene (MT) emitters [3, 4], and BVOC emissions and compound composition vary considerably under different temperature and light conditions through growing season [5, 6]. We characterize the canopy BVOC emissions variation from a Norway spruce dominated boreal forest in Central Sweden (Norunda, 60°05'N, 17°29'E). Air samples were taken during growing season (June to September 2013) from transparent dynamic branch chambers set up on Norway spruce at 20m agl. using a scaffolding tower. Air samples were collected every hour from the chamber with Tenax-TA adsorbent tubes and a pocket pump, and analyzed later by gas chromatography and a mass selective detector (GC-MS) to quantify trapped terpenoid compounds. Total terpenoids emission rates in August were found to be highest even though the highest average air temperature was observed in July. Isoprene could not be detected in any sample in June and in most samples from September, but during peak season. Emissions of Isoprene, MT and sesquiterpenes (SQT) showed a clear diurnal pattern in July and August with highest emissions at noon time, however, the composition of terpenoids was slightly changing among different months. The most complex chemical composition with 13 different MT species occurred in late July, while 9 SQT species occurred in the middle of August. However, the fraction of dominant MT species (Limonene, α-Pinene, β-Pinene and Camphene) of the total terpenoids emission was almost constant throughout the whole season from June to September except for β-Pinene which showed a higher fraction in August. References [1]M.Ehn et al., 2014, Nature, 506(7489), 476-479. [2]M.Kulmala et al., 2004, Atmos. Environ., 4, 557-562. [3]J.Rinne et al., 2005, Boreal Environ

  11. The Palaeoproterozoic Woodlands Formation of eastern Botswana-northwestern South Africa: lithostratigraphy and relationship with Transvaal Basin inversion structures

    NASA Astrophysics Data System (ADS)

    Eriksson, P. G.; Van Der Merwe, R.; Bumby, A. J.

    1998-11-01

    The Woodlands Formation (uppermost Pretoria Group) of eastern Botswana overlies thick quartzites of the Sengoma Formation (Magaliesberg Formation) and comprises a lower unit of interbedded mudrocks and fine-grained recrystallised quartzitic sandstones, succeeded by chaotic and very coarse-grained inferred slump deposits. Within the adjacent western region of South Africa, interbedded mudrocks and quartzitic sandstones stratigraphically overlying the Magaliesberg Formation are now assigned to the lower Woodlands Formation. Within the entire region, interference folding produced by northeast-southwest (F 1 and F 3) and northwest-southeast (F 2) compression, and concomitant faulting characterised inversion of the Pretoria Group basin. This deformation is of pre-Bushveld age and affected all units in the Pretoria Group, including the uppermost Silverton, Magaliesberg and Woodlands Formations, and intrusive Marico Hypabyssal Suite (pre-Bushveld) mafic sills. The Nietverdiend lobe of the Bushveld Complex, intrusive into this succession, was not similarly deformed. Movement along the major Mannyelanong Fault in the northwest of the study area post-dated Transvaal Basin inversion, after which the "upper Woodlands" chaotic slump deposits were formed. The latter must thus belong to a younger stratigraphical unit and is possibly analogous to apparently syntectonic sedimentary rocks (Otse Group) in the Otse Basin of eastern Botswana.

  12. Genetic signatures of natural selection in response to air pollution in red spruce (Picea rubens, Pinaceae).

    PubMed

    Bashalkhanov, Stanislav; Eckert, Andrew J; Rajora, Om P

    2013-12-01

    One of the most important drivers of local adaptation for forest trees is climate. Coupled to these patterns, however, are human-induced disturbances through habitat modification and pollution. The confounded effects of climate and disturbance have rarely been investigated with regard to selective pressure on forest trees. Here, we have developed and used a population genetic approach to search for signals of selection within a set of 36 candidate genes chosen for their putative effects on adaptation to climate and human-induced air pollution within five populations of red spruce (Picea rubens Sarg.), distributed across its natural range and air pollution gradient in eastern North America. Specifically, we used FST outlier and environmental correlation analyses to highlight a set of seven single nucleotide polymorphisms (SNPs) that were overly correlated with climate and levels of sulphate pollution after correcting for the confounding effects of population history. Use of three age cohorts within each population allowed the effects of climate and pollution to be separated temporally, as climate-related SNPs (n = 7) showed the strongest signals in the oldest cohort, while pollution-related SNPs (n = 3) showed the strongest signals in the youngest cohorts. These results highlight the usefulness of population genetic scans for the identification of putatively nonneutral evolution within genomes of nonmodel forest tree species, but also highlight the need for the development and application of robust methodologies to deal with the inherent multivariate nature of the genetic and ecological data used in these types of analyses.

  13. Combined fluorescence, reflectance, and ground measurements of a stressed Norway spruce forest for forest damage assessment

    NASA Technical Reports Server (NTRS)

    Banninger, C.

    1991-01-01

    The detection and monitoring of stress and damage in forested areas is of utmost importance to forest managers for planning purposes. Remote sensing are the most suitable means to obtain this information. This requires that remote sensing data employed in a forest survey be properly chosen and utilized for their ability to measure canopy spectral features directly related to key tree and canopy properties that are indicators of forest health and vitality. Plant reflectance in the visible to short wave IR regions (400 to 2500 nm) provides information on its biochemical, biophysical, and morphological make up, whereas plant fluorescence in the 400 to 750 nm region is more indicative of the capacity and functioning of its photosynthetic apparatus. A measure of both these spectral properties can be used to provide an accurate assessment of stress and damage within the forest canopy. Foliar chlorophyll and nitrogen are essential biochemical constituents required for the proper functioning and maintenance of a plant's biological processes. Chlorophyll-a is the prime reactive center for photosynthesis, by which a plant converts CO2 and H2O into necessary plant products. Nitrogen forms an important component of the amino-acids, enzymes, proteins, alkaloids, and cyanogenic compounds that make up a plant, including its pigments. Both chlorophyll and nitrogen have characteristic absorption features in the visible to short wave IR region. By measuring the wavelength position and depth of these features and the fluorescence response of the foliage, the health and vitality of a canopy can be ascertained. Examples for a stressed Norway spruce forest in south-eastern Austria are presented.

  14. The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub-green moss spruce forests

    NASA Astrophysics Data System (ADS)

    Orlova, M. A.; Lukina, N. V.; Smirnov, V. E.; Artemkina, N. A.

    2016-11-01

    Presently, among the works considering the influence of forest trees on soil properties, the idea that spruce ( Picea abies) promotes the acidification of soils predominates. The aim of this work is to assess the effects of spruce trees of different ages and Kraft classes on the acidity and content of available nutrient compounds in the soils under boreal dwarf shrub-green moss spruce forests by the example of forest soils in the Kola Peninsula. The soils are typical iron-illuvial podzols (Albic Rustic Podzols (Arenic)). Three probable ways of developing soils under spruce forests with the moss-dwarf shrub ground cover are considered. The soils under windfall-soil complexes of flat mesodepressions present the initial status. The acidity of organic soil horizons from the initial stage of mesodepression overgrowth to the formation of adult trees changed nonlinearly: the soil acidity reached its maximum under the 30-40-year-old trees and decreased under the trees older than 100 years. The contents of nitrogen and available nutrients increased. The acidity of the mineral soil horizons under the trees at the ages of 110-135 and 190-220 years was comparable, but higher than that under the 30-40-year-old trees. The differences in the strength and trends of the trees' effect on the soils are explained by the age of spruce trees and their belonging to different Kraft classes.

  15. Nature's patchwork: How water sources and soil salinity determine the distribution and structure of halophytic plant communities in arid environments of the Eastern Pamir.

    PubMed

    Mętrak, Monika; Chachulski, Łukasz; Navruzshoev, Dovutsho; Pawlikowski, Paweł; Rojan, Elżbieta; Sulwiński, Marcin; Suska-Malawska, Małgorzata

    2017-01-01

    The eastern part of the Pamir Mountains, located in Central Asia, is characterized by great climatic continentality and aridity. Wetlands developed in this hostile region are restricted to spring areas, terraces of shallow lakes or floodplains along rivers, and provide diversified ecosystem services e.g. as water reservoirs, refugia for rare species and pastures for domestic cattle. These ecosystems are particularly susceptible to climate changes, that in the Pamir Mountains result in increased temperatures, intense permafrost/glacial melt and alterations of precipitation patterns. Climatic changes affect pasture management in the mountains, causing overutilization of sites located at lower elevations. Thus, both climate and man-induced disturbances may violate the existing ecological equilibrium in high-mountain wetlands of the Eastern Pamir, posing a serious risk to their biodiversity and to food security of the local population. In this context, we sought to assess how environmental drivers (with special focus on soil features and potential water sources) shape the distribution and diversity of halophytic plant communities developed in valleys in the Eastern Pamir. This task was completed by means of a vegetation survey and comprehensive analyses of habitat conditions. The lake terraces and floodplains studied were covered by a repetitive mosaic of plant communities determined by differences in soil moisture and salinity. On lower, wetter sites, this patchwork was formed by Blysmus rufus dominated salt marshes, saline small sedge meadows and saline meadows with Kobresia royleana and Primula pamirica; and on drier, elevated sites, by endemic grasslands with Hordeum brevisubulatum and Puccinellia species and patches of xerohalophytic vegetation. Continuous instability of water sources and summer droughts occurring in the Pamir Mountains may lead to significant structural and functional transformations of described wetland ecosystems. Species more tolerant to

  16. Nature's patchwork: How water sources and soil salinity determine the distribution and structure of halophytic plant communities in arid environments of the Eastern Pamir

    PubMed Central

    Mętrak, Monika; Chachulski, Łukasz; Navruzshoev, Dovutsho; Pawlikowski, Paweł; Rojan, Elżbieta; Sulwiński, Marcin; Suska-Malawska, Małgorzata

    2017-01-01

    The eastern part of the Pamir Mountains, located in Central Asia, is characterized by great climatic continentality and aridity. Wetlands developed in this hostile region are restricted to spring areas, terraces of shallow lakes or floodplains along rivers, and provide diversified ecosystem services e.g. as water reservoirs, refugia for rare species and pastures for domestic cattle. These ecosystems are particularly susceptible to climate changes, that in the Pamir Mountains result in increased temperatures, intense permafrost/glacial melt and alterations of precipitation patterns. Climatic changes affect pasture management in the mountains, causing overutilization of sites located at lower elevations. Thus, both climate and man-induced disturbances may violate the existing ecological equilibrium in high-mountain wetlands of the Eastern Pamir, posing a serious risk to their biodiversity and to food security of the local population. In this context, we sought to assess how environmental drivers (with special focus on soil features and potential water sources) shape the distribution and diversity of halophytic plant communities developed in valleys in the Eastern Pamir. This task was completed by means of a vegetation survey and comprehensive analyses of habitat conditions. The lake terraces and floodplains studied were covered by a repetitive mosaic of plant communities determined by differences in soil moisture and salinity. On lower, wetter sites, this patchwork was formed by Blysmus rufus dominated salt marshes, saline small sedge meadows and saline meadows with Kobresia royleana and Primula pamirica; and on drier, elevated sites, by endemic grasslands with Hordeum brevisubulatum and Puccinellia species and patches of xerohalophytic vegetation. Continuous instability of water sources and summer droughts occurring in the Pamir Mountains may lead to significant structural and functional transformations of described wetland ecosystems. Species more tolerant to

  17. Crustal structure and rift tectonics across the Cauvery-Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Twinkle, D.; Rao, G. Srinivasa; Radhakrishna, M.; Murthy, K. S. R.

    2016-03-01

    The Cauvery-Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India-Sri Lanka-East Antarctica). In the present study, we carry out an integrated analysis of the potential field data across the basin to understand the crustal structure and the associated rift tectonics. The composite-magnetic anomaly map of the basin clearly shows the onshore-to-offshore structural continuity, and presence of several high-low trends related to either intrusive rocks or the faults. The Curie depth estimated from the spectral analysis of offshore magnetic anomaly data gave rise to 23 km in the offshore Cauvery-Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusive rocks that characterize the basin. The crustal models further reveal that the crust below southeast Indian shield margin is ˜36 km thick and thins down to as much as 13-16 km in the Ocean Continent Transition (OCT) region and increases to around 19-21 km towards deep oceanic areas of the basin. The faulted Moho geometry with maximum stretching in the Cauvery basin indicates shearing or low angle rifting at the time of breakup between India-Sri Lanka and the East Antarctica. However, the additional stretching observed in the Cauvery basin region could be ascribed to the subsequent rifting of Sri Lanka from India. The abnormal thinning of crust at the OCT is interpreted as the probable zone of emplaced Proto-Oceanic Crust (POC) rocks during the breakup. The derived crustal structure along with other geophysical data further reiterates sheared nature of the southern part of the ECMI.

  18. Surface Pollen Distribution from Alpine Vegetation in Eastern Tibet, China.

    PubMed

    Zhang, Yun; Kong, Zhaochen; Yang, Zhenjing; Wang, Li; Duan, Xiaohong

    2017-04-03

    We explore the relationship between modern pollen spectra and vegetation patterns in the Eastern Tibet, China in order to provide information on the representation of pollen taxa and improve the general knowledge of vertical pollen transport. Forty-two modern pollen samples collected in surface soil along two altitudinal transects allowed conclusions on vertical pollen dispersal from the alpine region of Dingqing County, Changdu district in Tibet. Discriminant analyses and detrended correspondence analysis (DCA) of 24 pollen taxa were used to further discuss the difference of modern pollen spectra in these alpine vegetation zones. The surface pollen assemblage is divided into three pollen zones, such as subalpine shrub meadow, montane coniferous forest and shrub steppe with sparse trees. Altitude and precipitation are two primary factors contributing to changes in surface pollen assemblage from alpine vegetation in the eastern Tibet. Large amounts of spruce pollen at higher elevations above the timberline might be introduced from lower elevations by upslope winds. Therefore, the interpretation of spruce pollen in the fossil record must take into account long distance upward wind transport. Moreover, the destruction of coniferous forest in the study area is well illustrated in the modern pollen rain.

  19. Nocardia aciditolerans sp. nov., isolated from a spruce forest soil.

    PubMed

    Golinska, Patrycja; Wang, Dylan; Goodfellow, Michael

    2013-05-01

    Actinomycetes growing on acidified starch-casein agar seeded with suspensions of litter and mineral soil from a spruce forest were provisionally assigned to the genus Nocardia based upon colonial properties. Representative isolates were found to grow optimally at pH 5.5, have chemotaxonomic and morphological features consistent with their assignment to the genus Nocardia and formed two closely related subclades in the Nocardia 16S rRNA gene tree. DNA:DNA relatedness assays showed that representatives of the subclades belong to a single genomic species. The isolates were distantly associated with their nearest phylogenetic neighbour, the type strain of Nocardia kruczakiae, and were distinguished readily from the latter based on phenotypic properties. On the basis of these data it is proposed that the isolates merit recognition as a new species, Nocardia aciditolerans sp. nov. The type strain is isolate CSCA68(T) (=KACC 17155(T) = NCIMB 14829(T) = DSM 45801(T)).

  20. Streptacidiphilus hamsterleyensis sp. nov., isolated from a spruce forest soil.

    PubMed

    Golinska, Patrycja; Kim, Byung-Yong; Dahm, Hanna; Goodfellow, Michael

    2013-12-01

    Three acidophilic actinobacteria, isolates LSCA2, FGG8 and HSCA14(T), recovered from spruce litter were examined using a polyphasic approach. Chemotaxonomic and morphological properties of the isolates were found to be consistent with their classification in the genus Streptacidiphilus. The isolates were shown to have identical 16S rRNA gene sequences and were most closely related to Streptacidiphilus neutrinimicus DSM 41755(T) (99.9 % similarity). However, DNA:DNA relatedness between isolate HSCA14(T) and the type strain of S. neutrinimicus was found to be low at 44.0 (±14.1) %. A combination of phenotypic features, including degradative and nutritional characteristics were shown to distinguish the isolates from their nearest phylogenetic neighbours. Data from this study show that the isolates form a novel species in the genus for which the name S. hamsterleyensis sp. nov. is proposed. The type strain is HSCA 14(T) (=DSM 45900(T) = KACC 17456(T) = NCIMB 14865(T)).

  1. Emission of volatile sulfur compounds from spruce trees

    SciTech Connect

    Rennenberg, H.; Huber, B.; Schroeder, P.; Stahl, K.; Haunold, W.; Georgil, H.W.; Slovik, S.; Pfanz, H. )

    1990-03-01

    Spruce (Picea abies L.) trees from the same clone were supplied with different, but low, amounts of plant available sulfate in the soil (9.7-18.1 milligrams per 100 grams of soil). Branches attached to the trees were enclosed in a dynamic gas exchange cuvette and analyzed for the emission of volatile sulfur compounds. Independent of the sulfate supply in the soil, H{sub 2}S was the predominant reduced sulfur compound continuously emitted from the branches with high rates during the day and low rates in the night. In the light, as well as in the dark, the rates of H{sub 2}S emission increased exponentially with increasing water vapor flux from the needles. Approximately 1 nanomole of H{sub 2}S was found to be emitted per mole of water. When stomata were closed completely, only minute emission of H{sub 2}S was observed. Apparently, H{sub 2}S emission from the needles is highly dependent on stromatal aperture, and permeation through the cuticle is negligible. In several experiments, small amounts of dimethylsulfide and carbonylsulfide were also detected in a portion of the samples. However, SO{sub 2} was the only sulfur compound consistently emitted from branches of spruce trees in addition to H{sub 2}S. Emission of SO{sub 2} mainly proceeded via an outburst starting before the beginning of the light period. The total amount of SO{sub 2} emitted from the needles during this outburst was correlated with the plant available sulfate in the soil. The diurnal changes in sulfur metabolism that may result in an outburst of SO{sub 2} are discussed.

  2. Yellowheaded spruce sawfly: Its ecology and management. Forest Service general technical report

    SciTech Connect

    Katovich, S.A.; McCullough, D.G.; Haack, R.A.

    1995-12-14

    The yellowheaded spruce sawfly (YHSS), Pikonema alaskensis (Rohwer), (Hymenoptera: Tenthredinidae), defoliates spruce, Picea sp., throughout the Northern United States and Canada. YHSS defoliation can result in substantial growth reduction and tree mortality. Young, open-grown trees, 3 to 18 feet in height and 5 to 9 years old, are more vulnerable to YHSS damage than are understory trees, older trees, or trees in dense stands. Young plantations and naturally regenerated stands of spruce YHSS defoliation, particularly in the Great Lakes region. Many Christmans trees, nursery stock, roadside and windbreak trees, and ornamental spruce are also damaged. Susceptibility to YHSS drops sharply once trees reach 10 to 12 years of age and stands reach the stage of crown closure.

  3. Physiological diagnosis of the health of spruce and fir at high elevations in the Southern Appalachians

    SciTech Connect

    McLaughlin, S.B.; Wullschleger, S.D.; Stone, A. )

    1994-06-01

    A sequence of field studies to evaluate causes of decreasing radial growth rates of red spruce at high elevations in the Great Smokey Mountains during the past 30 years has examined climatic signals, competition, xylem wood chemistry, soil chemistry, foliar nutrition and carbon allocation patterns. The resultant hypothesis that acid deposition alters red spruce growth through limiting calcium availability, and consequently net carbon assimilation, has now been tested in controlled greenhouse and field studies. Recent measurements of reduce respiration and increased photosynthesis of red spruce samplings in response to adding calcium in the field, provides additional evidence linking acid deposition to altered nutrition, physiology, and growth of red spruce. Initial data from physiological gradient analysis also support the occurrence of parallel elevational gradients in physiology of fraser fir.

  4. Red spruce decline in the northeastern US: hypotheses regarding the role of acid rain

    SciTech Connect

    Johnson, A.H.

    1983-11-01

    Red spruce have died in abnormal numbers in the high elevation forests of New York and New England during the past two decades while spruce in the southern Appalachians remain healthy. Investigations of insect damage, fungai pathogens, successional dynamics, competitive status, climate and weather patterns, and possible pollutant effects indicate that the decline was triggered by abiotic stress during the dry years of the 1960s. Tree response, as recorded in the pattern of annual rings, and the wide range of soil conditions in which spruce are declining, suggest drought or dry summers as key factors. Hypotheses regarding the role of acid deposition induced stress have been offered, but at present there is not evidence which clearly links acid deposition to spruce decline. Indirect effects of acid deposition on soils, direct effects of acid deposition on foliage, and interactions of acid deposition and drought stress are possible but unproven pathways by which acid deposition could be involved. 23 references, 6 figures, 1 table.

  5. Climate and red spruce growth and decline in the northern Appalachians

    PubMed Central

    Johnson, A. H.; Cook, E. R.; Siccama, T. G.

    1988-01-01

    Between the mid-1960s and mid-1980s, red spruce (Picea rubens Sarg.) died at unusual rates on the mountains of New York and western New England. We determined the relationship between standardized tree ring widths and monthly climate data for calibration and verification periods from 1856 to 1981 and found that after about 1960, there was a distinct shift in the temperature variables related to standardized ring widths in vigorous spruce. The beginning of widespread spruce mortality, regionwide growth decreases, and the shift in response to climate in the early 1960s corresponds to the onset of a decade of unusually cold winters and several consecutive years when severe winter damage was noted across the Northeast in this species. We suggest that the episodes of winter damage are an important initiating and synchronizing factor in the red spruce decline. PMID:16593962

  6. Complex postglacial recolonization inferred from population genetic structure of mottled sculpin Cottus bairdii in tributaries of eastern Lake Michigan, U.S.A.

    PubMed

    Homola, J J; Ruetz, C R; Kohler, S L; Thum, R A

    2016-11-01

    This study used analyses of the genetic structure of a non-game fish species, the mottled sculpin Cottus bairdii to hypothesize probable recolonization routes used by cottids and possibly other Laurentian Great Lakes fishes following glacial recession. Based on samples from 16 small streams in five major Lake Michigan, U.S.A., tributary basins, significant interpopulation differentiation was documented (overall FST = 0·235). Differentiation was complex, however, with unexpectedly high genetic similarity among basins as well as occasionally strong differentiation within basins, despite relatively close geographic proximity of populations. Genetic dissimilarities were identified between eastern and western populations within river basins, with similarities existing between eastern and western populations across basins. Given such patterns, recolonization is hypothesized to have occurred on three occasions from more than one glacial refugium, with a secondary vicariant event resulting from reduction in the water level of ancestral Lake Michigan. By studying the phylogeography of a small, non-game fish species, this study provides insight into recolonization dynamics of the region that could be difficult to infer from game species that are often broadly dispersed by humans.

  7. Accretionary prisms of the Sikhote-Alin Orogenic Belt: Composition, structure and significance for reconstruction of the geodynamic evolution of the eastern Asian margin

    NASA Astrophysics Data System (ADS)

    Kemkin, I. V.; Khanchuk, A. I.; Kemkina, R. A.

    2016-12-01

    We present overview for geological studies of the terranes of the Sikhote-Alin orogenic belt in the Russian Far East. The belt is formed by accretionary prisms with alternating tectonic packets of thrust-like slices which consist of complexly deformed marine (pelagic and hemipelagic deposits, as well as oceanic plateau and paleo-guyot fragments), marginal oceanic turbidites and chaotic (subduction mélange) formations. We reconstruct a stepwise history of accretion of paleo-oceanic crustal fragments of different ages, based on detailed lithological-biostratigraphic and structural analysis. We propose geodynamic model for evolution of the eastern margin of the paleo-Asian continent during the Mesozoic time by combining geological observations for the region with geological data for others terranes of the Sikhote-Alin Orogenic Belt. We recognize several principal Mesozoic geological processes that have led to formation of the continental crust at the eastern margin of Asia: (i) accretion of paleo-oceanic fragments to the continent margin during the subduction of the paleo-Pacific plate along the convergent margins, (ii) subsequent intense deformation of rocks of the accretionary prisms of the transform margin including folding and multiple thrusting which led to a multifold increase in thickness of sediments, (iii) formation of granitic-metamorphic complexes due to intrusion of the orogenic granites into the accretionary prisms.

  8. Influence of eastern hemlock (Tsuga canadensis L.) on fish community structure and function in headwater streams of the Delaware River basin

    USGS Publications Warehouse

    Ross, R.M.; Bennett, R.M.; Snyder, C.D.; Young, J.A.; Smith, D.R.; Lemarie, D.P.

    2003-01-01

    Hemlock (Tsuga canadensis) forest of the eastern U.S. are in decline due to invasion by the exotic insect hemlock woolly adelgid (Adelges tsugae). Aquatic biodiversity in hemlock ecosystems has not been documented; thus the true impact of the infestation cannot be assessed. We compared ichthyofaunal assemblages and trophic structure of streams draining hemlock and hardwood forests by sampling first- and second-order streams draining 14 paired hemlock and hardwood stands during base flows in July 1997 at the Delaware Water Gap National Recreation Area of Pennsylvania and New Jersey. Over 1400 fish of 15 species and 7 families were collected, but hemlock and hardwood streams individually harbored only one to four species. Brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were two to three times as prevalent in hemlock than hardwood streams. Insectivorous fishes occurred in significantly higher proportion in streams of hardwood (0.90) than hemlock (0.46) stands, while piscivores occurred more often in hemlock (0.85) than hardwood (0.54) stands. Functional (trophic) diversity of fishes in hemlock and second-order streams was numerically greater than that of hardwood and first-order streams. Species composition also differed by stream order and terrain type. Biodiversity is threatened at several levels within hemlock ecosystems at risk to the hemlock woolly adelgid in eastern U.S. forests.

  9. Inclination distributions and size measurements of hemlock and red spruce needles

    NASA Technical Reports Server (NTRS)

    Kimes, Daniel S.; Smith, J. A.

    1991-01-01

    Needle inclination angle distributions were plotted for 5 and 10 deg intervals for two hemlock trees and one red spruce. The distributions for the hemlock and spruce were similar, with the peak normal angle occurring between 10 and 20 deg. These distributions are between two theoretical (planophile and spherical) leaf angle distributions. The results can be used as an input to radiative transfer models that require a distribution of the orientation of the scattering elements of the canopy.

  10. AmeriFlux CA-Man Manitoba - Northern Old Black Spruce (former BOREAS Northern Study Area)

    SciTech Connect

    Amiro, Brian

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-Man Manitoba - Northern Old Black Spruce (former BOREAS Northern Study Area). Site Description - 55.880° N, 98.481° W, elevation of 259 m, Boreal coniferous: Black spruce; occasional larch present in poorly-drained areas. Groundcover is moss (feathermosses and Sphagnum), Labrador Tea, Vaccinium, and willows are a main component of the understory. It was established in 1993 as a BOREAS site.

  11. A spruce gene map infers ancient plant genome reshuffling and subsequent slow evolution in the gymnosperm lineage leading to extant conifers

    PubMed Central

    2012-01-01

    Background Seed plants are composed of angiosperms and gymnosperms, which diverged from each other around 300 million years ago. While much light has been shed on the mechanisms and rate of genome evolution in flowering plants, such knowledge remains conspicuously meagre for the gymnosperms. Conifers are key representatives of gymnosperms and the sheer size of their genomes represents a significant challenge for characterization, sequencing and assembling. Results To gain insight into the macro-organisation and long-term evolution of the conifer genome, we developed a genetic map involving 1,801 spruce genes. We designed a statistical approach based on kernel density estimation to analyse gene density and identified seven gene-rich isochors. Groups of co-localizing genes were also found that were transcriptionally co-regulated, indicative of functional clusters. Phylogenetic analyses of 157 gene families for which at least two duplicates were mapped on the spruce genome indicated that ancient gene duplicates shared by angiosperms and gymnosperms outnumbered conifer-specific duplicates by a ratio of eight to one. Ancient duplicates were much more translocated within and among spruce chromosomes than conifer-specific duplicates, which were mostly organised in tandem arrays. Both high synteny and collinearity were also observed between the genomes of spruce and pine, two conifers that diverged more than 100 million years ago. Conclusions Taken together, these results indicate that much genomic evolution has occurred in the seed plant lineage before the split between gymnosperms and angiosperms, and that the pace of evolution of the genome macro-structure has been much slower in the gymnosperm lineage leading to extent conifers than that seen for the same period of time in flowering plants. This trend is largely congruent with the contrasted rates of diversification and morphological evolution observed between these two groups of seed plants. PMID:23102090

  12. Distribution of long-range linkage disequilibrium and Tajima's D values in Scandinavian populations of Norway Spruce (Picea abies).

    PubMed

    Larsson, Hanna; Källman, Thomas; Gyllenstrand, Niclas; Lascoux, Martin

    2013-05-20

    The site frequency spectrum of mutations (SFS) and linkage disequilibrium (LD) are the two major sources of information in population genetics studies. In this study we focus on the levels of LD and the SFS and on the effect of sample size on summary statistics in 10 Scandinavian populations of Norway spruce. We found that previous estimates of a low level of LD were highly influenced by both sampling strategy and the fact that data from multiple loci were analyzed jointly. Estimates of LD were in fact heterogeneous across loci and increased within individual populations compared with the estimate from the total data. The variation in levels of LD among populations most likely reflects different demographic histories, although we were unable to detect population structure by using standard approaches. As in previous studies, we also found that the SFS-based test Tajima's D was highly sensitive to sample size, revealing that care should be taken to draw strong conclusions from this test when sample size is small. In conclusion, the results from this study are in line with recent studies in other conifers that have revealed a more complex and variable pattern of LD than earlier studies suggested and with studies in trees and humans that suggest that Tajima's D is sensitive to sample size. This has large consequences for the design of future association and population genetic studies in Norway spruce.

  13. Quantitative constraints on the lithospheric mantle discontinuity structure in eastern Canada from joint analysis of receiver function and surface wave data

    NASA Astrophysics Data System (ADS)

    Bailey, I. W.; Miller, M. S.; Darbyshire, F. A.

    2011-12-01

    Previous work has suggested that the Archean craton of central and eastern Canada contains a number of relict slabs, frozen in and radiating out from the center. This observation has been used to suggest that the craton's existence is due to the formation and dying out of ancient (~2 Ga) subduction zones at the craton edges in progressive Wilson cycles, leaving a chemically depleted and buoyant slab after each stage. Miller & Eaton (2010) used teleseismic S receiver functions to image a deep (200-260 km) sharp lithosphere-asthenosphere boundary and a number of negative polarity shallower, mid-lithospheric discontinuities. However, noise in the data and insufficient sampling from only 8 seismic stations meant that the discontinuities could only be interpreted using comparisons with results based on surface wave and heat flow analyses. To better understand the discontinuity structure across central and eastern Canada, we utilise data from a combination of 32 permanent and temporary broadband stations including those from the HuBLE experiment. From this extended dataset we attempt to constrain evidence for the observed discontinuities more quantitatively by combining both P and S receiver functions with Rayleigh wave phase velocity data in Monte Carlo based joint inversions for shear wave velocity structure. The crustal thickness and velocity is initially constrained by results from active source experiments and stacking of receiver functions. Our Monte Carlo approach allows us to investigate uncertainty in the Vp, density and attenuation parameters on the inferred Vs result and discontinuities, allowing for better constraints on recently reported internal structure of continental lithosphere in both Canada and other cratonic regions.

  14. Genetical genomics identifies the genetic architecture for growth and weevil resistance in spruce.

    PubMed

    Porth, Ilga; White, Richard; Jaquish, Barry; Alfaro, René; Ritland, Carol; Ritland, Kermit

    2012-01-01

    In plants, relationships between resistance to herbivorous insect pests and growth are typically controlled by complex interactions between genetically correlated traits. These relationships often result in tradeoffs in phenotypic expression. In this study we used genetical genomics to elucidate genetic relationships between tree growth and resistance to white pine terminal weevil (Pissodes strobi Peck.) in a pedigree population of interior spruce (Picea glauca, P. engelmannii and their hybrids) that was growing at Vernon, B.C. and segregating for weevil resistance. Genetical genomics uses genetic perturbations caused by allelic segregation in pedigrees to co-locate quantitative trait loci (QTLs) for gene expression and quantitative traits. Bark tissue of apical leaders from 188 trees was assayed for gene expression using a 21.8K spruce EST-spotted microarray; the same individuals were genotyped for 384 SNP markers for the genetic map. Many of the expression QTLs (eQTL) co-localized with resistance trait QTLs. For a composite resistance phenotype of six attack and oviposition traits, 149 positional candidate genes were identified. Resistance and growth QTLs also overlapped with eQTL hotspots along the genome suggesting that: 1) genetic pleiotropy of resistance and growth traits in interior spruce was substantial, and 2) master regulatory genes were important for weevil resistance in spruce. These results will enable future work on functional genetic studies of insect resistance in spruce, and provide valuable information about candidate genes for genetic improvement of spruce.

  15. Genetical Genomics Identifies the Genetic Architecture for Growth and Weevil Resistance in Spruce

    PubMed Central

    Porth, Ilga; White, Richard; Jaquish, Barry; Alfaro, René; Ritland, Carol; Ritland, Kermit

    2012-01-01

    In plants, relationships between resistance to herbivorous insect pests and growth are typically controlled by complex interactions between genetically correlated traits. These relationships often result in tradeoffs in phenotypic expression. In this study we used genetical genomics to elucidate genetic relationships between tree growth and resistance to white pine terminal weevil (Pissodes strobi Peck.) in a pedigree population of interior spruce (Picea glauca, P. engelmannii and their hybrids) that was growing at Vernon, B.C. and segregating for weevil resistance. Genetical genomics uses genetic perturbations caused by allelic segregation in pedigrees to co-locate quantitative trait loci (QTLs) for gene expression and quantitative traits. Bark tissue of apical leaders from 188 trees was assayed for gene expression using a 21.8K spruce EST-spotted microarray; the same individuals were genotyped for 384 SNP markers for the genetic map. Many of the expression QTLs (eQTL) co-localized with resistance trait QTLs. For a composite resistance phenotype of six attack and oviposition traits, 149 positional candidate genes were identified. Resistance and growth QTLs also overlapped with eQTL hotspots along the genome suggesting that: 1) genetic pleiotropy of resistance and growth traits in interior spruce was substantial, and 2) master regulatory genes were important for weevil resistance in spruce. These results will enable future work on functional genetic studies of insect resistance in spruce, and provide valuable information about candidate genes for genetic improvement of spruce. PMID:22973444

  16. Finders keepers, losers weepers - drought as a modifier of competition between European beech and Norway spruce -

    NASA Astrophysics Data System (ADS)

    Goisser, Michael; Blanck, Christian; Geppert, Uwe; Häberle, Karl-Heinz; Matyssek, Rainer; Grams, Thorsten E. E.

    2016-04-01

    Mixed stands of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) frequently reflect over-yielding, when compared to respective monospecific stands. Over-yielding is attributed to enhanced resource uptake efficiency through niche complementarity alleviating species competition. Under climate change, however, with severe and frequent summer drought, water limitation may become crucial in modifying the competitive interaction between neighboring beech and spruce trees. In view of the demands by silvicultural practice, basic knowledge from experimental field work about competitive versus facilitative interaction in maturing mixed beech-spruce forests is scarce. To this end, we investigate species-specific drought response including underlying mechanisms of species interaction in a maturing group-wise mixed beech-spruce forest, amongst 60 and 53 adult trees of beech and spruce, respectively (spruce 65 ± 2, beech 85 ± 4 years old). Severe and repeated experimental drought is being induced over several years through a stand-scale approach of rain throughfall exclusion (Kranzberg Forest Roof Experiment, KROOF). The experimental design comprises 6 roofed (E, automated, closing only during rain) and 6 control (C) plots with a total area of almost 1800 square meters. In 2015 minimum predawn potentials of -2.16 MPa and -2.26 MPa were reached in E for beech and spruce respectively. At the leaf level, spruce displayed high drought susceptibility reflected by a distinct decrease in both stomatal conductance and net CO2 uptake rate by more than 80% each, suggesting isohydric response. Beech rather displayed anisohydry indicated by less pronounced yet significant reduction of stomatal conductance and net CO2 uptake rate by more than 55% and 45%, respectively. Under the C regime, a negative species interaction effect on stomatal conductance was found in beech, contrasting with a positive effect in spruce. However, drought reversed the effect of

  17. Evidence of Variscan and Alpine tectonics in the structural and thermochronological record of the central Serbo-Macedonian Massif (south-eastern Serbia)

    NASA Astrophysics Data System (ADS)

    Antić, Milorad D.; Kounov, Alexandre; Trivić, Branislav; Spikings, Richard; Wetzel, Andreas

    2016-07-01

    The Serbo-Macedonian Massif (SMM) represents a composite crystalline belt within the Eastern European Alpine orogen, outcropping from the Pannonian basin in the north to the Aegean Sea in the south. The central parts of this massif (south-eastern Serbia) consist of the medium- to high-grade Lower Complex and the low-grade Vlasina Unit. Outcrop- and micro-scale ductile structures in this area document three major stages of ductile deformation. The earliest stage D1 is related to isoclinal folding, commonly preserved as up to decimetre-scale quartz-feldspar rootless fold hinges. D2 is associated with general south-eastward tectonic transport and refolding of earlier structures into recumbent metre- to kilometre-scale tight to isoclinal folds. Stages D1 and D2 could not be temporally separated and probably took place in close sequence. The age of these two ductile deformation stages was constrained to the Variscan orogeny based on indirect geological evidence (i.e. ca. 408-ca. 328). During this period, the SMM was involved in a transpressional amalgamation of the western and eastern parts of the Galatian super-terrane and subsequent collision with Laurussia. Outcrop-scale evidence of the final stage D3 is limited to spaced and crenulation cleavage, which are probably related to formation of large-scale open upright folds as reported previously. 40Ar/39Ar thermochronology was applied on hornblende, muscovite, and biotite samples in order to constrain the age of tectonothermal events and activity along major shear zones. These 40Ar/39Ar data reveal three major cooling episodes affecting the central SMM. Cooling below greenschist facies conditions in the western part of the Vlasina Unit took place in a post-orogenic setting (extensional or transtensional) in the early Permian (284 ± 1 Ma). The age of activity along the top-to-the-west shear zone formed within the orthogneiss in the Božica area of the Vlasina Unit was constrained to Middle Triassic (246 ± 1 Ma). This

  18. Modular organization of the white spruce (Picea glauca) transcriptome reveals functional organization and evolutionary signatures.

    PubMed

    Raherison, Elie S M; Giguère, Isabelle; Caron, Sébastien; Lamara, Mebarek; MacKay, John J

    2015-07-01

    Transcript profiling has shown the molecular bases of several biological processes in plants but few studies have developed an understanding of overall transcriptome variation. We investigated transcriptome structure in white spruce (Picea glauca), aiming to delineate its modular organization and associated functional and evolutionary attributes. Microarray analyses were used to: identify and functionally characterize groups of co-expressed genes; investigate expressional and functional diversity of vascular tissue preferential genes which were conserved among Picea species, and identify expression networks underlying wood formation. We classified 22 857 genes as variable (79%; 22 coexpression groups) or invariant (21%) by profiling across several vegetative tissues. Modular organization and complex transcriptome restructuring among vascular tissue preferential genes was revealed by their assignment to coexpression groups with partially overlapping profiles and partially distinct functions. Integrated analyses of tissue-based and temporally variable profiles identified secondary xylem gene networks, showed their remodelling over a growing season and identified PgNAC-7 (no apical meristerm (NAM), Arabidopsis transcription activation factor (ATAF) and cup-shaped cotyledon (CUC) transcription factor 007 in Picea glauca) as a major hub gene specific to earlywood formation. Reference profiling identified comprehensive, statistically robust coexpressed groups, revealing that modular organization underpins the evolutionary conservation of the transcriptome structure.

  19. Simultaneous Inversion of Interpolated Receiver Functions, Surface-wave Dispersion, and Gravity Observations for Lithospheric Structure Beneath the Eastern United States

    NASA Astrophysics Data System (ADS)

    Chai, C.; Ammon, C. J.; Maceira, M.; Herrmann, R. B.

    2015-12-01

    The unprecedented high-quality seismic data from Earthscope's Transportable Array provide us a great opportunity to investigate the subsurface structure beneath North America. Even with such a fine network, tightly constraining the 3D lithospheric structure is a challenge. Integrating complementary geophysical observations in simultaneous inversions has produced promising results. We have developed a receiver-function wavefield interpolation/smoothing method to enhance the complementariness of receiver functions and surface-wave dispersion. Combining information from adjacent seismic stations suppresses poorly sampled and difficult-to-interpret back-azimuthal variations and allows the stable extraction of the key features in the receiver-function wavefield. The interpolated receiver functions are inverted simultaneously with Rayleigh-wave phase and group velocities and Bouguer gravity observations to produce a robust estimate of the broad 3D shear-wave speed variations beneath the eastern United States. P-wave velocities and density variations are related to shear-speed using empirical velocity ratios and relations. We constrain the 3D variations to be laterally and vertically smooth. Application of the same methods to the western conterminous United States resulted in velocity images that are consistent with published models on the first order. With the completion of the Transportable Array deployment in the northeast US, the seismic dataset beneath the eastern U.S. region is complete. Preliminary inversions contain expected near-surface low shear-wave speeds associated with large basins and coastal regions and thicker crust beneath the interior compared with the coastal regions. Speeds in the upper mantle are generally typical, but the model includes several regions of relatively slow mantle beneath the northern Mississippi Embayment, the east coast, and beneath New England.

  20. Does the hydrodynamic, morphometric and sedimentary environment explain the structure of soft-bottom benthic assemblages in the Eastern Bay of Seine (English Channel)?

    NASA Astrophysics Data System (ADS)

    Dauvin, Jean-Claude; Lucas, Sabrina; Navon, Maxime; Lesourd, Sandric; Mear, Yann; Poizot, Emmanuel; Alizier, Sandrine

    2017-04-01

    It has been traditionally assumed that the distribution of the macrofauna is mainly related to the nature of the sediment and that the grain size plays a key role. Therefore in some cases such as in the coastal environment submitted to input of fine particles coming from land via estuary, the sediment is not the major factor explaining the spatial distribution of benthic species, assemblages and communities. In fact, sediment samples may not be representative of real life conditions of benthic organisms which are exposed to natural environment and three-dimensional structure of habitat and heterogeneity of sediments with several grain size classes. Based on data acquired in September 2008 and 2009 from the benthic sampling surveys in the eastern part of the Bay of Seine which is characterized by the dominance of heterometric sediment, the main aim of this paper is to study for the first time the existing link between the spatial distribution of the benthic species and assemblages and selected environmental variables such as sedimentary, hydrodynamic and morphometric data, to explain the real part of each abiotic factors in the spatio-temporal structuration of the benthic assemblages in this area at the mouth of the Seine estuary. Redundancy Analyses had permitted to distinguish six assemblages in relation to heterometry of the sediment; current speed, bathymetry and salinity. Generalized Linear Models permitted to explain between 30 and 89% of the variance within the chosen environmental factors. The species with a large distribution at the eastern part of the Bay of Seine were those showing the lowest percentage of explained variance while the species which were located in few stations were those showing the highest percentage of explained variance.

  1. Spatial variability in phytoplankton community structure along the eastern Arabian Sea during the onset of south-west monsoon

    NASA Astrophysics Data System (ADS)

    Ahmed, Ayaz; Kurian, Siby; Gauns, Mangesh; Chndrasekhararao, A. V.; Mulla, Amara; Naik, Bhagyashri; Naik, Hema; Naqvi, S. W. A.

    2016-05-01

    The Arabian Sea experiences moderate to weak upwelling along the south-west coast of India, which subsequently propagates towards the north. This causes variation in plankton community composition, which is addressed in the present study. Here we report the spatial variations in distribution of phytoplankton groups along the north-south transect in the eastern Arabian Sea based on marker pigments supported with flow-cytometric and microscopic analyses. 15 phytoplankton pigments were identified using High-performance liquid chromatography (HPLC) and the chemotaxonomic software (CHEMTAX) analysis associated these to seven major group of phytoplankton. The phytoplankton biomass, chlorophyll a (Chl a) was higher in southern stations with dominance of fucoxanthin whereas, divinyl chlorophyll a (divinyl Chl a), marker pigment of Prochlorococcus was present only in the northern region. Microscopic observation revealed the dominance of larger forms; diatoms (Chaetoceros coarctatum and Nitzschia sp.) and dinoflagellates (Scrippsiella sp., Oxytoxum nanum and Oxytoxum sp.) in the southern region. Furthermore, a study of plankton size distribution showed dominance of picoplankton (fpico) followed by nanoplankton (fnano) along the northern stations with comparatively higher microplankton (fmicro) in the south. This study clearly showed the influence of different environmental conditions on the phytoplankton community as reflected in dominance of diatoms in the southern (south of 12 °N) and that of picoplankton in the northern (north of 12 °N) region.

  2. Comparing modern and presettlement forest dynamics of a subboreal wilderness: does spruce budworm enhance fire risk?

    PubMed

    Sturtevant, Brian R; Miranda, Brian R; Shinneman, Douglas J; Gustafson, Eric J; Wolter, Peter T

    2012-06-01

    Insect disturbance is often thought to increase fire risk through enhanced fuel loadings, particularly in coniferous forest ecosystems. Yet insect disturbances also affect successional pathways and landscape structure that interact with fire disturbances (and vice-versa) over longer time scales. We applied a landscape succession and disturbance model (LANDIS-II) to evaluate the relative strength of interactions between spruce budworm (Choristoneura fumiferana) outbreaks and fire disturbances in the Boundary Waters Canoe Area (BWCA) in northern Minnesota (USA). Disturbance interactions were evaluated for two different scenarios: presettlement forests and fire regimes vs. contemporary forests and fire regimes. Forest composition under the contemporary scenario trended toward mixtures of deciduous species (primarily Betula papyrifera and Populus spp.) and shade-tolerant conifers (Picea mariana, Abies balsamea, Thuja occidentalis), with disturbances dominated by a combination of budworm defoliation and high-severity fires. The presettlement scenario retained comparatively more "big pines" (i.e., Pinus strobus, P. resinosa) and tamarack (L. laricina), and experienced less budworm disturbance and a comparatively less-severe fire regime. Spruce budworm disturbance decreased area burned and fire severity under both scenarios when averaged across the entire 300-year simulations. Contrary to past research, area burned and fire severity during outbreak decades were each similar to that observed in non-outbreak decades. Our analyses suggest budworm disturbances within forests of the BWCA have a comparatively weak effect on long-term forest composition due to a combination of characteristics. These include strict host specificity, fine-scaled patchiness created by defoliation damage, and advance regeneration of its primary host, balsam fir (A. balsamea) that allows its host to persist despite repeated disturbances. Understanding the nature of the three-way interaction between

  3. Comparing modern and presettlement forest dynamics of a subboreal wilderness: Does spruce budworm enhance fire risk?

    USGS Publications Warehouse

    Sturtevant, Brian R.; Miranda, Brian R.; Shinneman, Douglas J.; Gustafson, Eric J.; Wolter, Peter T.

    2012-01-01

    Insect disturbance is often thought to increase fire risk through enhanced fuel loadings, particularly in coniferous forest ecosystems. Yet insect disturbances also affect successional pathways and landscape structure that interact with fire disturbances (and vice-versa) over longer time scales. We applied a landscape succession and disturbance model (LANDIS-II) to evaluate the relative strength of interactions between spruce budworm (Choristoneura fumiferana) outbreaks and fire disturbances in the Boundary Waters Canoe Area (BWCA) in northern Minnesota (USA). Disturbance interactions were evaluated for two different scenarios: presettlement forests and fire regimes vs. contemporary forests and fire regimes. Forest composition under the contemporary scenario trended toward mixtures of deciduous species (primarily Betula papyrifera and Populus spp.) and shade-tolerant conifers (Picea mariana, Abies balsamea, Thuja occidentalis), with disturbances dominated by a combination of budworm defoliation and high-severity fires. The presettlement scenario retained comparatively more “big pines” (i.e., Pinus strobus, P. resinosa) and tamarack (L. laricina), and experienced less budworm disturbance and a comparatively less-severe fire regime. Spruce budworm disturbance decreased area burned and fire severity under both scenarios when averaged across the entire 300-year simulations. Contrary to past research, area burned and fire severity during outbreak decades were each similar to that observed in non-outbreak decades. Our analyses suggest budworm disturbances within forests of the BWCA have a comparatively weak effect on long-term forest composition due to a combination of characteristics. These include strict host specificity, fine-scaled patchiness created by defoliation damage, and advance regeneration of its primary host, balsam fir (A. balsamea) that allows its host to persist despite repeated disturbances. Understanding the nature of the three-way interaction

  4. Interspecific variation in resistance of two host tree species to spruce budworm

    NASA Astrophysics Data System (ADS)

    Fuentealba, Alvaro; Bauce, Éric

    2016-01-01

    Woody plants regularly sustain biomass losses to herbivorous insects. Consequently, they have developed various resistance mechanisms to cope with insect attack. However, these mechanisms of defense and how they are affected by resource availability are not well understood. The present study aimed at evaluating and comparing the natural resistance (antibiosis and tolerance) of balsam fir (Abies balsamea [L.] Mill.) and white spruce (Picea glauca [Moench) Voss] to spruce budworm, Choristoneura fumiferana (Clem.), and how drainage site quality as a component of resource availability affects the expression of resistance over time (6 years). Our results showed that there are differences in natural resistance between the two tree species to spruce budworm, but it was not significantly affected by drainage quality. Balsam fir exhibited higher foliar toxic secondary compounds concentrations than white spruce in all drainage classes, resulting in lower male pupal mass, survival and longer male developmental time. This, however, did not prevent spruce budworm from consuming more foliage in balsam fir than in white spruce. This response suggests that either natural levels of measured secondary compounds do not provide sufficient toxicity to reduce defoliation, or spruce budworm has developed compensatory mechanisms, which allow it to utilize food resources more efficiently or minimize the toxic effects that are produced by its host's defensive compounds. Larvae exhibited lower pupal mass and higher mortality in rapidly drained and subhygric sites. Drainage class also affected the amount of foliage destroyed but its impact varied over the years and was probably influenced by climatic variables. These results demonstrate the complexity of predicting the effect of resource availability on tree defenses, especially when other confounding environmental factors can affect tree resource allocation and utilization.

  5. Correlation by Rb-Sr geochronology of garnet growth histories from different structural levels within the Tauern Window, Eastern Alps

    SciTech Connect

    Christensen, John N.; Selverstone, Jane; Rosenfeld, John L.; Depaolo, Donald J.

    1993-06-01

    In order to evaluate rates of tectonometamorphic processes, growth rates of garnets from metamorphic rocks of the Tauern Window, Eastern Alps were measured using Rb-Sr isotopes. The garnet growth rates were determined from Rb-Sr isotopic zonation of single garnet crystals and the Rb-Sr isotopic compositions of their associated rock matrices. Garnets were analyzed from the Upper Schieferhulle (USH) and Lower Schieferhulle (LSH) within the Tauern Window. Two garnets from the USH grew at rates of 0.67(-0.13)+0.19 mm/million years and 0.88(-0.19)+0.34 mm/million years, respectively, indicating an average growth duration of 5.4 +- 1.7 million years. The duration of growth coupled with the amount of rotation recorded by inclusion trails in the USH garnets yields an average shear-strain rate during garnet growth of 2.7(-0.7)+1.2 x 10(-14) s-1 . Garnet growth in the sample from the USH occurred between 35.4 +- 0.6 and 30 +- 0.8 Ma. The garnet from the LSH grew at a rate of 0.23 +- 0.015 mm/mil lion years, between 62 +- 1.5 Ma and 30.2 +- 1.5 Ma. Contemporaneous cessation of garnet growth in both units at approximately 30 Ma is in accord with previous dating of the thermal peak of metamorphism in the Tauern Window. Correlation with previously published pressure-temperature paths for garnets from the USH and LSH yields approximate rates of burial, exhumation and heating during garnet growth. Assuming that these P - T paths are applicable to the garnets in this study, the contemporaneous exhumation rates recorded by garnet in the USH and LSH were approximately 4(-2)+3 mm/year and 2 +- 1 mm/year, respectively. [References: 34

  6. The spruce shoot gall midges (Diptera: Cecidomyiidae): Piceacecis, a new genus for a non-native pest of Norway spruce from Europe and its native American relative

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dasineura abietiperda (Henschel), a European pest of Norway spruce, Picea abies (Pinaceae), is reported as new to North America. Damage symptoms are illustrated and an outline of its biology is given. A new genus, Piceacecis Gagné is described to include it and its North American relative, Phytophag...

  7. Seismic velocity structure of the crust and shallow mantle of the Central and Eastern United States by seismic surface wave imaging

    USGS Publications Warehouse

    Pollitz, Fred; Mooney, Walter D.

    2016-01-01

    Seismic surface waves from the Transportable Array of EarthScope's USArray are used to estimate phase velocity structure of 18 to 125 s Rayleigh waves, then inverted to obtain three-dimensional crust and upper mantle structure of the Central and Eastern United States (CEUS) down to ∼200 km. The obtained lithosphere structure confirms previously imaged CEUS features, e.g., the low seismic-velocity signature of the Cambrian Reelfoot Rift and the very low velocity at >150 km depth below an Eocene volcanic center in northwestern Virginia. New features include high-velocity mantle stretching from the Archean Superior Craton well into the Proterozoic terranes and deep low-velocity zones in central Texas (associated with the late Cretaceous Travis and Uvalde volcanic fields) and beneath the South Georgia Rift (which contains Jurassic basalts). Hot spot tracks may be associated with several imaged low-velocity zones, particularly those close to the former rifted Laurentia margin.

  8. 2D magnetotelluric imaging of the Anqing-Guichi ore district, Yangtze metallogenic belt, eastern China: An insight into the crustal structure and tectonic units

    NASA Astrophysics Data System (ADS)

    Chen, Xiangbin; Yan, Jiayong

    2016-08-01

    Two parallel NW-trending magnetotelluric (MT) profiles were placed perpendicularly to the main structures of the Anqing-Guichi ore district, one of the seven ore districts in the middle-lower Yangtze River metallogenic belt of eastern China. In October-December 2013, the MT data acquisition was carried out at 117 sites with 0.5-1 km site spacing. The MT data has a good quality in the frequency range between 320 and 0.01 Hz. The dimensionality analysis and 2D resistivity inversion results indicate that: (1) the deep of the ore district with three-dimensional structural characteristics, but two-dimensional structural characteristics for shallow; (2) there is a clear correlation between resistivity and the main geological units of the ore district, as well as correlation with mapped surface faults; (3) the Gandan deep fault (GDF) and Jiangnan deep fault (JNF) extend from the surface to 10 km deep, with dip of NW45°, and dip angles larger than 60°. A series of NE-trending acidic intrusive rocks were controlled by the GDF.

  9. Spatial genetic analyses reveal cryptic population structure and migration patterns in a continuously harvested grey wolf (Canis lupus) population in north-eastern Europe.

    PubMed

    Hindrikson, Maris; Remm, Jaanus; Männil, Peep; Ozolins, Janis; Tammeleht, Egle; Saarma, Urmas

    2013-01-01

    Spatial genetics is a relatively new field in wildlife and conservation biology that is becoming an essential tool for unravelling the complexities of animal population processes, and for designing effective strategies for conservation and management. Conceptual and methodological developments in this field are therefore critical. Here we present two novel methodological approaches that further the analytical possibilities of STRUCTURE and DResD. Using these approaches we analyse structure and migrations in a grey wolf (Canislupus) population in north-eastern Europe. We genotyped 16 microsatellite loci in 166 individuals sampled from the wolf population in Estonia and Latvia that has been under strong and continuous hunting pressure for decades. Our analysis demonstrated that this relatively small wolf population is represented by four genetic groups. We also used a novel methodological approach that uses linear interpolation to statistically test the spatial separation of genetic groups. The new method, which is capable of using program STRUCTURE output, can be applied widely in population genetics to reveal both core areas and areas of low significance for genetic groups. We also used a recently developed spatially explicit individual-based method DResD, and applied it for the first time to microsatellite data, revealing a migration corridor and barriers, and several contact zones.

  10. Lateral extrusion of the northern Tibetan Plateau interpreted from seismic images, potential field data, and structural analysis of the eastern Kunlun fault

    NASA Astrophysics Data System (ADS)

    Xu, Xiao; Gao, Rui; Dong, Shuwen; Wang, Haiyan; Guo, Xiaoyu

    2017-01-01

    The extrusion model suggests that the India-Eurasia collision triggered lateral escape of the Tibetan Plateau via strike-slip faults from south to north. However, questions remain as to how the collision resulted in the different geological settings of northern Tibet. The area between the Haiyuan fault and the eastern Kunlun fault is ideal for investigating whether major strike-slip faults contributed to lateral extrusion of the plateau. This study uses a deep seismic profile spanning a 257 km transect, along with regional geologic, gravity, and magnetic data. Examining our results integrated with those of previous studies, we propose that the block between the Elashan and Riyueshan faults extruded southward under the background of a large-scale eastward extrusion of the Tibetan Plateau. According to regional tectonic events, the north-dipping intracrustal seismic reflectors that appear beneath the Western Qinling orogen are the remnants of the Indosinian Mianlue suture zone. The subduction of the Mianlue Ocean led to the underthrusting of South China beneath the Qinling orogen, similar to the process that occurred in the Western Kunlun Range and central Alps. As a result, the Moho was duplicated beneath the Western Qinling orogen. Southward extrusion resulted in the offset of the eastern Kunlun fault from the Diebu-Bailongjiang fault, which transferred part of the Western Qinling orogen to the Ruo'ergai basin and pulled the Ruo'ergai basin as well. Based on interpretations of structures and other evident features, we develop a kinematic model to specifically explain how the northern Tibetan Plateau between the Elashan and Riyueshan faults, located between the Haiyuan and Kunlun faults, accommodates southwesterly compression.

  11. Multi-scale integrated structural and aeromagnetic analysis to guide tectonic models: An example from the eastern Musgrave Province, Central Australia

    NASA Astrophysics Data System (ADS)

    Aitken, Alan R. A.; Betts, Peter G.

    2009-10-01

    In many polydeformed Precambrian provinces, the understanding of their tectonic history is limited by insufficient exposure, which leads to difficulty in developing links between local and regional architecture, and results in poorly constrained models of their regional-scale architecture. High-resolution aeromagnetic data allows interpretation and modelling at a scale comparable to structural mapping, and by integrating these methods, these links can be developed with high confidence. As an example, we integrate structural mapping, aeromagnetic data interpretation and 3D magnetic inversions in a multi-scale structural analysis of the polydeformed eastern Musgrave Province in central Australia. Deformation during the ca. 1200 Ma Musgravian Orogeny is characterised by an originally northeast-trending structural grain defined by shear zones and tight to isoclinal folds at all scales. 3D magnetic inversion models of syn-to-post Musgravian granites indicate that this structural grain is predominantly west dipping. This architecture suggests that a northeast-oriented fold and thrust belt developed as a result of northwest-southeast compression in central Australia during the Musgravian Orogeny. The next deformation event is characterised by an array of originally east-southeast trending shear zones that truncate and offset the Musgravian structural grain with apparent dextral displacements of up to 1 km. These shear zones are commonly co-located with mafic and granitic dykes, suggesting a dilational origin, and they are interpreted to have initiated under northeast-southwest extension during the ca. 1080 Ma Giles Event. The architecture of these two Mesoproterozoic events was later extensively overprinted by two deformation events during the Pan-African aged (ca. 550 Ma) Petermann Orogeny. The first is characterised by the widespread reactivation of Mesoproterozoic structures, resulting in a network of shear zones of variable orientation, and the second is characterised

  12. Geology of the Spruce Pine District, Avery, Mitchell, and Yancy Counties, North Carolina

    USGS Publications Warehouse

    Brobst, Donald Albert

    1962-01-01

    The Spruce Pine pegmatite district, a northeastward-trending belt 25 miles long and 10 miles wide, lies in parts of Avery, Mitchell, and Yancey Counties in the Blue Ridge Province of western North Carolina. The most abundant rocks in the district are interlayered mica and amphibole gneisses and schists, all of which are believed to be of Precambrian age. These rocks are cut by small bodies of dunite and associated rocks of Precambrian (?) age, large bodies of alaskite and associated pegmatite of early Paleozoic age, and basaltic and diabasic dikes and sills of Triassic (?) age. The rocks of the district have been weathered to saprolite that is locally 50 feet thick. The major structure in the area is a southwestward-plunging asymmetrical synclinorium that has its steeper limb on the northwest side. Feldspar, muscovite as sheet and scrap (ground) mica, and kaolin from the alaskite and associated pegmatite account for over 90 percent of the total mineral production of the district. Amounts of other pegmatite minerals, including quartz, beryl, columbite-tantalite, rare-earth and uranium minerals are an extremely small part of the mineral resources. Actual or potential products from other rocks are olivine, vermiculite, asbestos, talc, chromium and nickel, soapstone, mica schist, garnet, kyanite, dolomite marble, and construction materials.

  13. Predicting adaptive phenotypes from multilocus genotypes in Sitka spruce (Picea sitchensis) using random forest.

    PubMed

    Holliday, Jason A; Wang, Tongli; Aitken, Sally

    2012-09-01

    Climate is the primary driver of the distribution of tree species worldwide, and the potential for adaptive evolution will be an important factor determining the response of forests to anthropogenic climate change. Although association mapping has the potential to improve our understanding of the genomic underpinnings of climatically relevant traits, the utility of adaptive polymorphisms uncovered by such studies would be greatly enhanced by the development of integrated models that account for the phenotypic effects of multiple single-nucleotide polymorphisms (SNPs) and their interactions simultaneously. We previously reported the results of association mapping in the widespread conifer Sitka spruce (Picea sitchensis). In the current study we used the recursive partitioning algorithm 'Random Forest' to identify optimized combinations of SNPs to predict adaptive phenotypes. After adjusting for population structure, we were able to explain 37% and 30% of the phenotypic variation, respectively, in two locally adaptive traits--autumn budset timing and cold hardiness. For each trait, the leading five SNPs captured much of the phenotypic variation. To determine the role of epistasis in shaping these phenotypes, we also used a novel approach to quantify the strength and direction of pairwise interactions between SNPs and found such interactions to be common. Our results demonstrate the power of Random Forest to identify subsets of markers that are most important to climatic adaptation, and suggest that interactions among these loci may be widespread.

  14. Formalized classification of moss litters in swampy spruce forests of intermontane depressions of Kuznetsk Alatau

    NASA Astrophysics Data System (ADS)

    Efremova, T. T.; Avrova, A. F.; Efremov, S. P.

    2016-09-01

    The approaches of multivariate statistics have been used for the numerical classification of morphogenetic types of moss litters in swampy spruce forests according to their physicochemical properties (the ash content, decomposition degree, bulk density, pH, mass, and thickness). Three clusters of moss litters— peat, peaty, and high-ash peaty—have been specified. The functions of classification for identification of new objects have been calculated and evaluated. The degree of decomposition and the ash content are the main classification parameters of litters, though all other characteristics are also statistically significant. The final prediction accuracy of the assignment of a litter to a particular cluster is 86%. Two leading factors participating in the clustering of litters have been determined. The first factor—the degree of transformation of plant remains (quality)—specifies 49% of the total variance, and the second factor—the accumulation rate (quantity)— specifies 26% of the total variance. The morphogenetic structure and physicochemical properties of the clusters of moss litters are characterized.

  15. Conifer stored resources and resistance to a fungus associated with the spruce bark beetle Ips typographus.

    PubMed

    Lahr, Eleanor C; Krokene, Paal

    2013-01-01

    Bark beetles and associated fungi are among the greatest natural threats to conifers worldwide. Conifers have potent defenses, but resistance to beetles and fungal pathogens may be reduced if tree stored resources are consumed by fungi rather than used for tree defense. Here, we assessed the relationship between tree stored resources and resistance to Ceratocystis polonica, a phytopathogenic fungus vectored by the spruce bark beetle Ips typographus. We measured phloem and sapwood nitrogen, non-structural carbohydrates (NSC), and lipids before and after trees were attacked by I. typographus (vectoring C. polonica) or artificially inoculated with C. polonica alone. Tree resistance was assessed by measuring phloem lesions and the proportion of necrotic phloem around the tree's circumference following attack or inoculation. While initial resource concentrations were unrelated to tree resistance to C. polonica, over time, phloem NSC and sapwood lipids declined in the trees inoculated with C. polonica. Greater resource declines correlated with less resistant trees (trees with larger lesions or more necrotic phloem), suggesting that resource depletion may be caused by fungal consumption rather than tree resistance. Ips typographus may then benefit indirectly from reduced tree defenses caused by fungal resource uptake. Our research on tree stored resources represents a novel way of understanding bark beetle-fungal-conifer interactions.

  16. Hydraulic efficiency compromises compression strength perpendicular to the grain in Norway spruce trunkwood

    PubMed Central

    2011-01-01

    The aim of this study was to investigate bending stiffness and compression strength perpendicular to the grain of Norway spruce (Picea abies (L.) Karst.) trunkwood with different anatomical and hydraulic properties. Hydraulically less safe mature sapwood had bigger hydraulic lumen diameters and higher specific hydraulic conductivities than hydraulically safer juvenile wood. Bending stiffness (MOE) was higher, whereas radial compression strength lower in mature than in juvenile wood. A density-based tradeoff between MOE and hydraulic efficiency was apparent in mature wood only. Across cambial age, bending stiffness did not compromise hydraulic efficiency due to variation in latewood percent and because of the structural demands of the tree top (e.g. high flexibility). Radial compression strength compromised, however, hydraulic efficiency because it was extremely dependent on the characteristics of the “weakest” wood part, the highly conductive earlywood. An increase in conduit wall reinforcement of earlywood tracheids would be too costly for the tree. Increasing radial compression strength by modification of microfibril angles or ray cell number could result in a decrease of MOE, which would negatively affect the trunk’s capability to support the crown. We propose that radial compression strength could be an easily assessable and highly predictive parameter for the resistance against implosion or vulnerability to cavitation across conifer species, which should be topic of further studies. PMID:22058609

  17. Structural development of the central Kyrenia Range (north Cyprus) in its regional setting in the eastern Mediterranean region

    NASA Astrophysics Data System (ADS)

    Robertson, A. H. F.; Kinnaird, T. C.

    2016-01-01

    A detailed structural analysis of the Mesozoic-Cenozoic geological development of the central segment of the Kyrenia Range in its regional tectonic context is given here. The structural evidence comes from five structural traverses, outcrop observations, small-scale structures and related regional evidence. The majority of the structures are fault planes, of which a subordinate number exhibit slickenlines (fault plane data, n = 2688; with kinematics, n = 537). Additional kinematic data were obtained from C-S fabrics and folds. Small-scale structures in each stratigraphic unit were `backstripped' to reveal relative chronology. Synthesis of the structural information indicates three phases of convergence-related deformation: (1) Late Cretaceous, associated with greenschist facies metamorphism, followed by exhumation that was probably associated with WNW-ESE to ENE-WSW-trending high-angle faulting; (2) Mid-Eocene, associated with southward thrusting, coupled with ~N-S strike-slip (transfer faulting) and oblique faulting in an overall sinistral transpressive stress regime; (3) Late Miocene-earliest Pliocene, involving southward thrusting and folding, localised back-thrusting, extensive fault reactivation and large-scale segmentation of the range. Intense uplift of the Kyrenia Range took place during the Plio-Pleistocene, possibly related to the collision of the Eratosthenes Seamount with the Cyprus trench to the south of the island. The three main convergent phases relate to stages of northward subduction and diachronous continental collision affecting the northerly, active continental margin of the Southern Neotethys.

  18. Classifying black and white spruce pollen using layered machine learning.

    PubMed

    Punyasena, Surangi W; Tcheng, David K; Wesseln, Cassandra; Mueller, Pietra G

    2012-11-01

    Pollen is among the most ubiquitous of terrestrial fossils, preserving an extended record of vegetation change. However, this temporal continuity comes with a taxonomic tradeoff. Analytical methods that improve the taxonomic precision of pollen identifications would expand the research questions that could be addressed by pollen, in fields such as paleoecology, paleoclimatology, biostratigraphy, melissopalynology, and forensics. We developed a supervised, layered, instance-based machine-learning classification system that uses leave-one-out bias optimization and discriminates among small variations in pollen shape, size, and texture. We tested our system on black and white spruce, two paleoclimatically significant taxa in the North American Quaternary. We achieved > 93% grain-to-grain classification accuracies in a series of experiments with both fossil and reference material. More significantly, when applied to Quaternary samples, the learning system was able to replicate the count proportions of a human expert (R(2) = 0.78, P = 0.007), with one key difference - the machine achieved these ratios by including larger numbers of grains with low-confidence identifications. Our results demonstrate the capability of machine-learning systems to solve the most challenging palynological classification problem, the discrimination of congeneric species, extending the capabilities of the pollen analyst and improving the taxonomic resolution of the palynological record.

  19. Organellar Genomes of White Spruce (Picea glauca): Assembly and Annotation.

    PubMed

    Jackman, Shaun D; Warren, René L; Gibb, Ewan A; Vandervalk, Benjamin P; Mohamadi, Hamid; Chu, Justin; Raymond, Anthony; Pleasance, Stephen; Coope, Robin; Wildung, Mark R; Ritland, Carol E; Bousquet, Jean; Jones, Steven J M; Bohlmann, Joerg; Birol, Inanç

    2015-12-08

    The genome sequences of the plastid and mitochondrion of white spruce (Picea glauca) were assembled from whole-genome shotgun sequencing data using ABySS. The sequencing data contained reads from both the nuclear and organellar genomes, and reads of the organellar genomes were abundant in the data as each cell harbors hundreds of mitochondria and plastids. Hence, assembly of the 123-kb plastid and 5.9-Mb mitochondrial genomes were accomplished by analyzing data sets primarily representing low coverage of the nuclear genome. The assembled organellar genomes were annotated for their coding genes, ribosomal RNA, and transfer RNA. Transcript abundances of the mitochondrial genes were quantified in three developmental tissues and five mature tissues using data from RNA-seq experiments. C-to-U RNA editing was observed in the majority of mitochondrial genes, and in four genes, editing events were noted to modify ACG codons to create cryptic AUG start codons. The informatics methodology presented in this study should prove useful to assemble organellar genomes of other plant species using whole-genome shotgun sequencing data.

  20. Organellar Genomes of White Spruce (Picea glauca): Assembly and Annotation

    PubMed Central

    Jackman, Shaun D.; Warren, René L.; Gibb, Ewan A.; Vandervalk, Benjamin P.; Mohamadi, Hamid; Chu, Justin; Raymond, Anthony; Pleasance, Stephen; Coope, Robin; Wildung, Mark R.; Ritland, Carol E.; Bousquet, Jean; Jones, Steven J. M.; Bohlmann, Joerg; Birol, Inanç

    2016-01-01

    The genome sequences of the plastid and mitochondrion of white spruce (Picea glauca) were assembled from whole-genome shotgun sequencing data using ABySS. The sequencing data contained reads from both the nuclear and organellar genomes, and reads of the organellar genomes were abundant in the data as each cell harbors hundreds of mitochondria and plastids. Hence, assembly of the 123-kb plastid and 5.9-Mb mitochondrial genomes were accomplished by analyzing data sets primarily representing low coverage of the nuclear genome. The assembled organellar genomes were annotated for their coding genes, ribosomal RNA, and transfer RNA. Transcript abundances of the mitochondrial genes were quantified in three developmental tissues and five mature tissues using data from RNA-seq experiments. C-to-U RNA editing was observed in the majority of mitochondrial genes, and in four genes, editing events were noted to modify ACG codons to create cryptic AUG start codons. The informatics methodology presented in this study should prove useful to assemble organellar genomes of other plant species using whole-genome shotgun sequencing data. PMID:26645680

  1. Element levels in birch and spruce wood ashes: green energy?

    PubMed

    Reimann, Clemens; Ottesen, Rolf Tore; Andersson, Malin; Arnoldussen, Arnold; Koller, Friedrich; Englmaier, Peter

    2008-04-15

    Production of wood ash has increased strongly in the last ten years due to the increasing popularity of renewable and CO(2)-neutral heat and energy production via wood burning. Wood ashes are rich in many essential plant nutrients. In addition they are alkaline. The idea of using the waste ash as fertiliser in forests is appealing. However, wood is also known for its ability to strongly enrich certain heavy metals from the underlying soils, e.g. Cd, without any anthropogenic input. Concentrations of 26 chemical elements (Ag, As, Au, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sr, Ti, and Zn) in 40 samples each of birch and spruce wood ashes collected along a 120 km long transect in southern Norway are reported. The observed maximum concentrations are 1.3 wt.% Pb, 4.4 wt.% Zn and 203 mg/kg Cd in birch wood ashes. Wood ashes can thus contain very high heavy metal concentrations. Spreading wood ashes in a forest is a major anthropogenic interference with the natural biogeochemical cycles. As with the use of sewage sludge in agriculture the use of wood ashes in forests clearly needs regulation.

  2. Streptacidiphilus durhamensis sp. nov., isolated from a spruce forest soil.

    PubMed

    Golinska, Patrycja; Ahmed, Lina; Wang, Dylan; Goodfellow, Michael

    2013-08-01

    The taxonomic position of three acidophilic actinobacteria, strains FGG38, FGG39 and FSCA67(T), isolated from the fermentation litter layer of a spruce forest soil was established using a polyphasic approach. The strains were shown to have chemotaxonomic and morphological properties consistent with their classification in the genus Streptacidiphilus and formed a distinct phyletic line in the Streptacidiphilus 16S rRNA gene tree being most closely related to Streptacidiphilus albus DSM 41753(T) (99.4 % similarity). DNA:DNA relatedness data showed that isolate FSCA67(T) and the type strain of S. albus belonged to markedly distinct genomic species. The isolates had many phenotypic properties in common and were distinguished readily from their closest phylogenetic neighbours in the Streptacidiphilus gene tree using a broad range of these features. Based on the combined genotypic and phenotypic data the three isolates are considered to represent a new Streptacidiphilus species. The name Streptacidiphilus durhamensis sp. nov. is proposed for this taxon with isolate FSCA67(T) (=DSM 45796(T) = KACC 17154(T) = NCIMB 14828(T)) [corrected] as the type strain.

  3. Actinospica durhamensis sp. nov., isolated from a spruce forest soil.

    PubMed

    Golinska, Patrycja; Zucchi, Tiago Domingues; Silva, Leonardo; Dahm, Hanna; Goodfellow, Michael

    2015-08-01

    Seven acidophilic actinobacteria isolated from humus and mineral layers of a spruce forest soil were examined using a polyphasic approach. Chemotaxonomic properties of the isolates were found to be consistent with their classification in the genus Actinospica. The strains formed a distinct phyletic line in the Actinospica 16S rRNA gene tree being most closely related to Actinospica robiniae DSM 44927(T) (98.7-99.3 % similarity). DNA:DNA relatedness between isolate CSCA57(T) and the type strain of A. robiniae was found to be low at 40.8 (±6.6) %. The isolates were shown to have many phenotypic properties in common and were distinguished readily from the type strains of Actinospica acidiphila and A. robiniae using a range of phenotypic features. On the basis of these data the seven isolates were considered to represent a new species for which the name Actinospica durhamensis sp. nov. is proposed. The type strain of the species is CSCA 57(T) (=DSM 46820(T) = NCIMB 14953(T)).

  4. Expression of the β-glucosidase gene Pgβglu-1 underpins natural resistance of white spruce against spruce budworm

    PubMed Central

    Mageroy, Melissa H; Parent, Geneviève; Germanos, Gaby; Giguère, Isabelle; Delvas, Nathalie; Maaroufi, Halim; Bauce, Éric; Bohlmann, Joerg; Mackay, John J

    2015-01-01

    Periodic outbreaks of spruce budworm (SBW) affect large areas of ecologically and economically important conifer forests in North America, causing tree mortality and reduced forest productivity. Host resistance against SBW has been linked to growth phenology and the chemical composition of foliage, but the underlying molecular mechanisms and population variation are largely unknown. Using a genomics approach, we discovered a β-glucosidase gene, Pgβglu-1, whose expression levels and function underpin natural resistance to SBW in mature white spruce (Picea glauca) trees. In phenotypically resistant trees, Pgβglu-1 transcripts were up to 1000 times more abundant than in non-resistant trees and were highly enriched in foliage. The encoded PgβGLU-1 enzyme catalysed the cleavage of acetophenone sugar conjugates to release the aglycons piceol and pungenol. These aglycons were previously shown to be active against SBW. Levels of Pgβglu-1 transcripts and biologically active acetophenone aglycons were substantially different between resistant and non-resistant trees over time, were positively correlated with each other and were highly variable in a natural white spruce population. These results suggest that expression of Pgβglu-1 and accumulation of acetophenone aglycons is a constitutive defence mechanism in white spruce. The progeny of resistant trees had higher Pgβglu-1 gene expression than non-resistant progeny, indicating that the trait is heritable. With reported increases in the intensity of SBW outbreaks, influenced by climate, variation of Pgβglu-1 transcript expression, PgβGLU-1 enzyme activity and acetophenone accumulation may serve as resistance markers to better predict impacts of SBW in both managed and wild spruce populations. PMID:25302566

  5. Expression of the β-glucosidase gene Pgβglu-1 underpins natural resistance of white spruce against spruce budworm.

    PubMed

    Mageroy, Melissa H; Parent, Geneviève; Germanos, Gaby; Giguère, Isabelle; Delvas, Nathalie; Maaroufi, Halim; Bauce, Éric; Bohlmann, Joerg; Mackay, John J

    2015-01-01

    Periodic outbreaks of spruce budworm (SBW) affect large areas of ecologically and economically important conifer forests in North America, causing tree mortality and reduced forest productivity. Host resistance against SBW has been linked to growth phenology and the chemical composition of foliage, but the underlying molecular mechanisms and population variation are largely unknown. Using a genomics approach, we discovered a β-glucosidase gene, Pgβglu-1, whose expression levels and function underpin natural resistance to SBW in mature white spruce (Picea glauca) trees. In phenotypically resistant trees, Pgβglu-1 transcripts were up to 1000 times more abundant than in non-resistant trees and were highly enriched in foliage. The encoded PgβGLU-1 enzyme catalysed the cleavage of acetophenone sugar conjugates to release the aglycons piceol and pungenol. These aglycons were previously shown to be active against SBW. Levels of Pgβglu-1 transcripts and biologically active acetophenone aglycons were substantially different between resistant and non-resistant trees over time, were positively correlated with each other and were highly variable in a natural white spruce population. These results suggest that expression of Pgβglu-1 and accumulation of acetophenone aglycons is a constitutive defence mechanism in white spruce. The progeny of resistant trees had higher Pgβglu-1 gene expression than non-resistant progeny, indicating that the trait is heritable. With reported increases in the intensity of SBW outbreaks, influenced by climate, variation of Pgβglu-1 transcript expression, PgβGLU-1 enzyme activity and acetophenone accumulation may serve as resistance markers to better predict impacts of SBW in both managed and wild spruce populations.

  6. Sources of Respired Carbon in a Northern Minnesota Ombrotrophic Spruce Bog: Preliminary 14C Results from the SPRUCE Site.

    NASA Astrophysics Data System (ADS)

    Guilderson, T. P.; McNicol, G.; Machin, A.; Hanson, P. J.; McFarlane, K. J.; Osuna, J. L.; Pett-Ridge, J.; Singleton, M. J.

    2014-12-01

    A significant uncertainty in future land-surface carbon budgets is the response of wetlands to climate change. A corollary and related question is the future net climate (radiative) forcing impact from wetlands. Active wetlands emit both CO2 and CH4 to the atmosphere. CH4 is, over a few decades, a much more potent greenhouse gas than CO2. CO2 has a longer atmospheric lifetime and a longer 'tail' to its radiative influence. Whether wetlands are a net source or sink of atmospheric carbon under future climate change will depend on ecosystem response to rising temperatures and elevated CO2. The largest uncertainty in future wetland C-budgets, and their climate forcing is the stability of the large below-ground carbon stocks, often in the form of peat, and the partitioning of CO2 and CH4 released via ecosystem respiration. In advance of a long-term experimental warming and elevated CO2 manipulation at the DOE Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) site in the Marcell Experimental Forest, we have characterized the source of respired carbon used for both the production of CO2 and CH4. Samples were collected in early June, late July, and will be collected in early September from three large (~1.1 m2, ~0.5m3) chambers from the control plot, and two of the experimental plots selected for heating (+9°C, +4.5°C). Early June fluxes from the three chambers were ~5500 mgC-m-2-d-1 and ~16 mgC-m-2-d-1 for CO2 and CH4 respectively. Radiocarbon analysis of CO2 and CH4 indicate that the source for the respired carbon is for the most part recent, with most 14C values between 30 and 40‰ - i.e., carbon that was photosynthetically fixed in the last few years. In concert with rising air and ground temperatures fluxes in late July increased to ~6500 mgC-m-2-d-1 and ~86 mgC-m-2-d-1. Although deep-heating was initiated in mid to late June we hypothesize that the July respiration signal is dominated by the regular seasonal cycle of natural warming

  7. Foraging habitats of lactating northern fur seals are structured by thermocline depths and submesoscale fronts in the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Nordstrom, Chad A.; Battaile, Brian C.; Cotté, Cédric; Trites, Andrew W.

    2013-04-01

    The relationships between fine-scale oceanographic features, prey aggregations, and the foraging behavior of top predators are poorly understood. We investigated whether foraging patterns of lactating northern fur seals (Callorhinus ursinus) from two breeding colonies located in different oceanographic domains of the eastern Bering Sea (St. Paul Island—shelf; Bogoslof Island—oceanic) were a function of submesoscale oceanographic features. We tested this by tracking 87 lactating fur seals instrumented with bio-logging tags (44 St. Paul Island, 43 Bogoslof Island) during July-September, 2009. We identified probable foraging hotspots using first-passage time analysis and statistically linked individual areas of high-use to fine-scale oceanographic features using mixed-effects Cox-proportional hazard models. We found no overlap in foraging areas used by fur seals from the two islands, but a difference in the duration of their foraging trips—trips from St. Paul Island were twice as long (7.9 d average) and covered 3-times the distance (600 km average) compared to trips from Bogoslof Island. St. Paul fur seals also foraged at twice the scale (mean radius=12 km) of Bogoslof fur seals (6 km), which suggests that prey were more diffuse near St. Paul Island than prey near Bogoslof Island. Comparing first passage times with oceanographic covariates revealed that foraging hotspots were linked to thermocline depth and occurred near submesoscale surface fronts (eddies and filaments). St. Paul fur seals that mixed epipelagic (night) and benthic (day) dives primarily foraged on-shelf in areas with deeper thermoclines that may have concentrated prey closer to the ocean floor, while strictly epipelagic (night) foragers tended to use waters with shallower thermoclines that may have aggregated prey closer to the surface. Fur seals from Bogoslof Island foraged almost exclusively over the Bering Sea basin and appeared to hunt intensively along submesoscale fronts that may have

  8. Genetic Variation and Population Structure of American Mink Neovison vison from PCB-Contaminated and Non-Contaminated Locales in Eastern North America

    PubMed Central

    Wirgin, Isaac; Maceda, Lorraine; Waldman, John; Mayack, David T.

    2015-01-01

    American mink Neovison vison may be particularly vulnerable to toxicities of persistent contaminants such as PCBs because of their aquatic-based diet, position near the top of the food web, and small deme sizes. Furthermore, ranched mink are sensitive to reproductive toxicities of fish diets from PCB-polluted sites. The upper Hudson River is highly contaminated with PCBs and previous studies have shown elevated hepatic burdens of total and coplanar PCBs in mink collected near the river compared with those from more distant locales in New York and elsewhere. We hypothesized that bioaccumulation of PCBs in Hudson River mink has reduced their levels of genetic diversity or altered their genetic population structure. To address this, we conducted microsatellite DNA analysis on collections made in proximity to and from more distant locales in the Hudson River watershed, elsewhere in New York State, and at other sites in eastern North America including New Brunswick, four locales in Ontario, multiple drainages in Maine, and two ecoregions in Rhode Island. We did not find reduced genetic diversity at the individual or population levels in mink collected near (< 6 km) to PCB hotspots in the Hudson River nor evidence of altered population structure. Consistent with their distribution in small localized and isolated demes, we did find significant genetic population structure among many mink collections in New York State and elsewhere. Depending on the analytical approach used, genetically distinct populations numbered between 16 when using STRUCTURE to 19-20 when using Exact G tests, FST, or AMOVA analyses. Genetically distinct population units were found among major ecoregions and minor ecoregions in New York State, among different hydrologic subunits within the Hudson River watershed, among spatially separate locales in Ontario, and among most watersheds in Maine. However, despite this localization and potential heightened impact of stressors, genetic diversity and genetic

  9. Use of artificial trees to assess dry deposition in spruce stands

    NASA Astrophysics Data System (ADS)

    Dambrine, E.; Pollier, B.; Bonneau, M.; Ignatova, N.

    In order to quantify the contribution of dry deposition to net throughfall composition in spruce, plastic Christmas trees were set up next to real spruce trees of approximately similar height in clearings of the Strengbach catchment (Vosges Mountains, France). Bulk precipitation and throughfall chemistry under the artificial trees, the real spruce trees, and in 3 spruce stands aged 15, 35 and 90 yr were monitored for 8.5 months. Fluxes of base cations in net throughfall below plastic trees were, on average, 1.5 times higher (Ca, Mg), 1.3 times higher (Na) or close (K, Mn) to those in bulk precipitation. Ratios in net throughfall between the fluxes of Ca, Mg, K and Mn, on the one hand, and Na on the other hand, were considered as representative of the composition of dry deposition. Assuming that foliar leaching of Na was negligible, the ratio between Na fluxes in net throughfall under living and plastic canopies was used as a particle deposition index. Using this index, particulate deposition was computed for the real spruce trees in the clearings as well as in the 3 closed stands. Results confirmed that the Ca and Mg flux in net throughfall was mainly supplied by dry deposition whereas K and Mn originated from foliar leaching. The increase in net throughfall fluxes of Ca and Mg with stand age appeared mainly related to an increase in dry deposition.

  10. Transverse tectonic structural elements across Himalayan mountain front, eastern Arunachal Himalaya, India: Implication of superposed landform development on analysis of neotectonics

    NASA Astrophysics Data System (ADS)

    Bhakuni, S. S.; Luirei, Khayingshing; Kothyari, Girish Ch.; Imsong, Watinaro

    2017-04-01

    Structural and morphotectonic signatures in conjunction with the geomorphic indices are synthesised to trace the role of transverse tectonic features in shaping the landforms developed along the frontal part of the eastern Arunachal sub-Himalaya. Mountain front sinuosity (Smf) index values close to one are indicative of the active nature of the mountain front all along the eastern Arunachal Himalaya, which can be directly attributed to the regional uplift along the Himalayan Frontal Thrust (HFT). However, the mountain front is significantly sinusoidal around junctions between HFT/MBT (Main Boundary Thrust) and active transverse faults. The high values of stream length gradient (SL) and stream steepness (Ks) indices together with field evidence of fault scarps, offset of terraces, and deflection of streams are markers of neotectonic uplift along the thrusts and transverse faults. This reactivation of transverse faults has given rise to extensional basins leading to widening of the river courses, providing favourable sites for deposition of recent sediments. Tectonic interactions of these transverse faults with the Himalayan longitudinal thrusts (MBT/HFT) have segmented the mountain front marked with varying sinuosity. The net result is that a variety of tectonic landforms recognized along the mountain front can be tracked to the complex interactions among the transverse and longitudinal tectonic elements. Some distinctive examples are: in the eastern extremity of NE Himalaya across the Dibang River valley, the NW-SE trending mountain front is attenuated by the active Mishmi Thrust that has thrust the Mishmi crystalline complex directly over the alluvium of the Brahmaputra plains. The junction of the folded HFT and Mishmi Thrust shows a zone of brecciated and pulverized rocks along which transverse axial planar fracture cleavages exhibit neotectonic activities in a transverse fault zone coinciding with the Dibang River course. Similarly, the transverse faults cut the

  11. Diversity and three-dimensional structures of the alpha Mcr of the methanogenic Archaea from the anoxic region of Tucuruí Lake, in Eastern Brazilian Amazonia

    PubMed Central

    Santana, Priscila Bessa; Junior, Rubens Ghilardi; Alves, Claudio Nahum; Silva, Jeronimo Lameira; McCulloch, John Anthony; Schneider, Maria Paula Cruz; da Costa da Silva, Artur

    2012-01-01

    Methanogenic archaeans are organisms of considerable ecological and biotechnological interest that produce methane through a restricted metabolic pathway, which culminates in the reaction catalyzed by the Methyl-coenzyme M reductase (Mcr) enzyme, and results in the release of methane. Using a metagenomic approach, the gene of the α subunit of mcr (mcrα) was isolated from sediment sample from an anoxic zone, rich in decomposing organic material, obtained from the Tucuruí hydroelectric dam reservoir in eastern Brazilian Amazonia. The partial nucleotide sequences obtained were 83 to 95% similar to those available in databases, indicating a low diversity of archaeans in the reservoir. Two orders were identified - the Methanomicrobiales, and a unique Operational Taxonomic Unit (OTU) forming a clade with the Methanosarcinales according to low bootstrap values. Homology modeling was used to determine the three-dimensional (3D) structures, for this the partial nucleotide sequence of the mcrα were isolated and translated on their partial amino acid sequences. The 3D structures of the archaean Mcrα observed in the present study varied little, and presented approximately 70% identity in comparison with the Mcrα of Methanopyrus klanderi. The results demonstrated that the community of methanogenic archaeans of the anoxic C1 region of the Tucurui reservoir is relatively homogeneous. PMID:22481885

  12. [Prediction of photolysis half-lives of PCDD /Fs adsorbed on spruce needles optimized by genetic algorithm].

    PubMed

    Niu, Jun-feng; Yu, Gang; Han, Wen-ya

    2005-03-01

    Adopting quantum chemical parameters of PCDD/Fs computed with quantum chemical PM3 algorithm, quantitative structure-property relationship (QSPR) model, which could predict photolysis half-life (t1/2) of PCDD/Fs adsorbed to spruce [Picea abies (L.) Karst.] needle surfaces, is established using genetic algorithm (GA) algorithm. It is considered that the main factors affecting lg t1/2 of PCDD/Fs are the energy of the highest occupied molecular orbital (EHOMO), ELUMO - EHOMO and average molecular polarizability (alpha). The lg t1/2 values increase with the increasing of EHOMO and a. The relationship between the lg t1/2 values and ELUMO - EHOMO is a parabolic curve. The lg t1/2 values increase with the increasing of ELUMO - EHOMO when ELUMO - EHOMO > or = 7.847 and decrease with the increasing of when ELUMO - EHOMO < or = 7.847.

  13. Research aircraft observations of the mesoscale and microscale structure of a cold front over the eastern Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Bond, Nicholas A.; Shapiro, M. A.

    1991-01-01

    The structure of an oceanic cold front is described on the basis of research aircraft observations taken during the Ocean Storms field experiment. Synoptic and mesoscale analyses compare the structure of an upper-level jet-front system observed slightly downstream from the wind speed maximum to its structure in the upstream entrance region. Stratospheric potential vorticity and ozone were found within the frontal zone down to about 800 mb. Microscale analyses of the front near the sea surface were carried out for a portion of the front having the signature of a 'rope' cloud in satellite imagery. A narrow (less than 1 km) zone of upward motion (about 4 m/s) and of horizontal shear (about 0.01/s) characterized the front near the surface. Significant alongfront variability was found, including lateral displacements in the frontal zone where there were weaker updrafts.

  14. Stratigraphy, petrology, and structure of the Pingston terrane, Mount Hayes C-5 and C-6 quadrangles, eastern Alaska Range, Alaska

    NASA Astrophysics Data System (ADS)

    Nokleberg, W. J.; Schwab, C. E.; Miyaoka, R. T.; Buhrmaster, C. L.

    Recent field, petrologic, and structural studies of the Pingston terrane in the Mount Hayes C-5 and C-6 quandrangles reveal that in this area the terrane: (1) has a highly distinctive stratigraphy, age, petrology (relict textures, relict minerals, and metamorphic facies), and structure; and (2) differs markedly from that described in previous studies. These more recent studies indicate that the major rock types, in order of decreasing abundance, are meta-andesite, metadacite and metarhyodacite flows and (or) tuff, metabasalt, metagabbro, metavolcanic graywacke, metagray-wacke, metasiltstone, metaquartzite or metachert, and very sparse marble. The general petrography of the major rock units in the Pingston terrane is given.

  15. Delineating ecological regions in marine systems: Integrating physical structure and community composition to inform spatial management in the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Baker, Matthew R.; Hollowed, Anne B.

    2014-11-01

    Characterizing spatial structure and delineating meaningful spatial boundaries have useful applications to understanding regional dynamics in marine systems, and are integral to ecosystem approaches to fisheries management. Physical structure and drivers combine with biological responses and interactions to organize marine systems in unique ways at multiple scales. We apply multivariate statistical methods to define spatially coherent ecological units or ecoregions in the eastern Bering Sea. We also illustrate a practical approach to integrate data on species distribution, habitat structure and physical forcing mechanisms to distinguish areas with distinct biogeography as one means to define management units in large marine ecosystems. We use random forests to quantify the relative importance of habitat and environmental variables to the distribution of individual species, and to quantify shifts in multispecies assemblages or community composition along environmental gradients. Threshold shifts in community composition are used to identify regions with distinct physical and biological attributes, and to evaluate the relative importance of predictor variables to determining regional boundaries. Depth, bottom temperature and frontal boundaries were dominant factors delineating distinct biological communities in this system, with a latitudinal divide at approximately 60°N. Our results indicate that distinct climatic periods will shift habitat gradients and that dynamic physical variables such as temperature and stratification are important to understanding temporal stability of ecoregion boundaries. We note distinct distribution patterns among functional guilds and also evidence for resource partitioning among individual species within each guild. By integrating physical and biological data to determine spatial patterns in community composition, we partition ecosystems along ecologically significant gradients. This may provide a basis for defining spatial management

  16. Investigating Nitrous Oxide Fluxes along a Harvested Red Spruce Forest Chronosequence

    NASA Astrophysics Data System (ADS)

    Mahoney, Kristie; Kellman, Lisa

    2010-05-01

    Forest harvesting can alter soil physical, chemical and biological functioning, shifting the fluxes of greenhouse gases to the atmosphere on the scale of months to decades. Clearcut harvesting is a standard management practice in many temperate forest regions, yet our current understanding of how this alters the balance of production and consumption of nitrous oxide (N2O) in these soils is poorly understood and quantified. This study investigates soil N2O fluxes across a clearcut harvest red spruce forest chronosequence in eastern Canada with six post-harvest sites (stand ages 0 - 83 years) and one uncut control old growth (125+ yrs) forest site. Nitrous oxide surface fluxes along with soil temperature and moisture were measured biweekly through the growing season, and supplemented with laboratory based experiments designed to understand the controls of moisture, temperature and N-status upon harvested soil cores (1 year). Over the chronosequence, soils acted as a net sink during the 0 - 0.5 year period immediately following harvesting (-0.84 ± 0.80 ?g N2O-N/m2/hr), followed by a net source in stands aged 0.5 - 5 years (3.27 ± 1.50 ?g N2O-N/m2/hr), with fluxes declining to background control forest levels (0.17 ± 0.45 ?g N2O-N/m2/hr) within 20 years. Overall, high spatial and temporal variability in field fluxes were documented, with negative fluxes observed at all stands and comprising approximately 46% of the measured fluxes. Additionally, no significant correlations were observed between N2O fluxes and soil temperature and moisture in the field data. Post harvest fluxes measured in controlled laboratory experiments pointed to N availability as the major control upon flux magnitudes. Nitrogen amendments resulted in positive soil fluxes that increased with elevated temperature and under optimal moisture conditions. Under N-limiting conditions (no N amendments) however, enhanced sink activity was observed at elevated temperatures.

  17. Seasonal variation of nitrogen oxides, ozone and biogenic volatile organic compound concentrations and fluxes at Norway spruce forest

    NASA Astrophysics Data System (ADS)

    Juran, Stanislav; Vecerova, Kristyna; Holisova, Petra; Zapletal, Milos; Pallozzi, Emanuele; Guidolotti, Gabriele; Calfapietra, Carlo; Vecera, Zbynek; Cudlin, Pavel; Urban, Otmar

    2015-04-01

    Dynamics of nitrogen oxides (NOx) and ozone concentration and their depositions were investigated on the Norway spruce forest at Bily Kriz experimental station at the Silesian Beskydy Mountains (north-eastern part of the Czech Republic). Both NOx and ozone concentration and fluxes were modelled for the whole season and covering thus different climate conditions. Data were recorded for three consecutive years and therefore deeper analyses were performed. During the summer 2014 BVOC field campaign was carried out using proton-transfer-reaction-time-of-flight-mass-spectrometry (PTR-TOF, Ionicon Analytik GmbH, Innsbruck, Austria) and volatile organic compound of biogenic origin (BVOC) were measured at the different levels of tree canopies. By the same time BVOC were trapped into the Tenax tubes (Markes International Ltd., UK) and put afterwards for thermal desorption (Markes Unity System 2, Markes International Ltd., UK) to GS-MS analysis (TSQ Quntum XLS triple Quadrupole, Thermo Scientific, USA). Thus data of different levels of canopies together with different spectra of monoterpenes were obtained. Interesting comparison of both methods will be shown. It was the first BVOC field campaign using PTR technique at any of the forest in the Czech Republic. Highest fluxes and concentrations were recorded around the noon hours, represented particularly by monoterpenes, especially α-pinen and limonene. Other BVOCs than monoterpenes were negligible. Variation of fluxes between different canopies levels was observed, highlighting difference in shaded and sun exposed leaves. Sun leaves emitted up to 2.4 nmol m-2 s-1 of monoterpenes, while shaded leaves emitted only up to 0.6 nmol m-2 s-1 when measured under standard conditions (irradiance 1000 µmol m-2 s-1; temperature 30°C). We discuss here the importance of the most common Norway spruce tree forests in the Czech Republic in bi-directional exchanges of important secondary pollutant such as ozone and nitrogen oxides, their

  18. Ecological patterns, distribution and population structure of Prionace glauca (Chondrichthyes: Carcharhinidae) in the tropical-subtropical transition zone of the north-eastern Pacific.

    PubMed

    Vögler, Rodolfo; Beier, Emilio; Ortega-García, Sofía; Santana-Hernández, Heriberto; Valdez-Flores, J Javier

    2012-02-01

    Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994-96/2000-02) and in coastal oceanic waters (2003-2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles' aggregations and pregnant females towards coastal waters and the presence of adult males' aggregations towards oceanic waters. The species exhibited horizontal segregation by sex-size and vertical segregation by sex. Distribution of the sex-size groups at oceanic waters was seasonally affected by the latitude; however, at coastal oceanic waters mainly females were influenced by the longitude. Latitudinal changes on the horizontal distribution were coupled to the seasonal forward and backward of water masses through the study area. Adult males showed positive relationship with high temperatures and high-salinities waters (17.0°-20.0 °C; 34.2-34.4) although they were also detected in low-salinities waters. The distribution of juvenile males mainly occurred beyond low temperatures and low-salinities waters (14.0°-15.0 °C; 33.6-34.1), suggesting a wide tolerance of adult males to explore subartic and subtropical waters. At oceanic areas, adult females were aggregated towards latitudes <25.0°N, mainly associated to subtropical waters during summer. The distribution of juvenile females indicated its preference by lower temperatures and more saline waters. Presence of pregnant females suggests that the eastern tropical Pacific off México represents an ecological key region to the reproductive cycle of P. glauca.

  19. Simultaneous Inversion of Receiver Functions, Surface-wave Dispersion, and Gravity Observations for Lithospheric Structure Beneath the Central and Eastern United States

    NASA Astrophysics Data System (ADS)

    Chai, C.; Ammon, C. J.; Herrmann, R. B.

    2014-12-01

    In contrast with the western United States (US), the eastern US has been less a focus for detailed passive seismological imaging of the crust and upper mantle. However, in the last few years, the EarthScope-USArray Transportable Array has substantially increased the available high-quality observations that sample the "stable" regions of North America with a roughly uniform ~70km spacing. The result is an unprecedented opportunity to illuminate the subsurface and to explore how upper crustal phenomena relate to deeper crustal and upper mantle structure and processes, which likely exert some control on the regional tectonics. But even with such a fine network, tightly constraining the subsurface 3D geologic variations is a challenge. We combine the complementary sensitivities P-wave receiver functions, surface-wave dispersion, and wavenumber-filtered gravity variations to constrain lateral variations in shear-wave speed beneath the eastern US and southeastern Canada. The receiver-function wavefield is interpolated and smoothed to equalize the lateral sensitivity of the receiver functions and the surface-wave dispersion and to simplify the receiver functions. Combining information from adjacent stations through interpolation suppresses poorly sampled and difficult to interpret back-azimuthal variations and allows the stable extraction of the key features in the receiver-function wavefield. We use a hybrid 3D, multi-objective inversion that provides more constraints than individual inversions, and generally produces a more robust estimate of the subsurface structure. The subsurface model is parameterized with shear-wave speed (the primary sensitivity of the surface-wave dispersion and P-wave receiver functions) within one-degree cells that are modeled using 1D seismic calculations. We relate P-wave speed and density variations to shear-speed using velocity ratios and density-velocity relations and we constrain the 3D variations to be laterally and vertically smooth

  20. Recovery of aboveground plant biomass and productivity after fire in mesic and dry black spruce forests of interior Alaska

    USGS Publications Warehouse

    Mack, M.C.; Treseder, K.K.; Manies, K.L.; Harden, J.W.; Schuur, E.A.G.; Vogel, J.G.; Randerson, J.T.; Chapin, F. S.

    2008-01-01

    Plant biomass accumulation and productivity are important determinants of ecosystem carbon (C) balance during post-fire succession. In boreal black spruce (Picea mariana) forests near Delta Junction, Alaska, we quantified aboveground plant biomass and net primary productivity (ANPP) for 4 years after a 1999 wildfire in a well-drained (dry) site, and also across a dry and a moderately well-drained (mesic) chronosequence of sites that varied in time since fire (2 to ???116 years). Four years after fire, total biomass at the 1999 burn site had increased exponentially to 160 ?? 21 g m-2 (mean ?? 1SE) and vascular ANPP had recovered to 138 ?? 32 g m-2 y -1, which was not different than that of a nearby unburned stand (160 ?? 48 g m-2 y-1) that had similar pre-fire stand structure and understory composition. Production in the young site was dominated by re-sprouting graminoids, whereas production in the unburned site was dominated by black spruce. On the dry and mesic chronosequences, total biomass pools, including overstory and understory vascular and non-vascular plants, and lichens, increased logarithmically (dry) or linearly (mesic) with increasing site age, reaching a maximum of 2469 ?? 180 (dry) and 4008 ?? 233 g m-2 (mesic) in mature stands. Biomass differences were primarily due to higher tree density in the mesic sites because mass per tree was similar between sites. ANPP of vascular and non-vascular plants increased linearly over time in the mesic chronosequence to 335 ?? 68 g m-2 y -1 in the mature site, but in the dry chronosequence it peaked at 410 ?? 43 g m-2 y-1 in a 15-year-old stand dominated by deciduous trees and shrubs. Key factors regulating biomass accumulation and production in these ecosystems appear to be the abundance and composition of re-sprouting species early in succession, the abundance of deciduous trees and shrubs in intermediate aged stands, and the density of black spruce across all stand ages. A better understanding of the controls

  1. Hot water extraction and steam explosion as pretreatments for ethanol production from spruce bark.

    PubMed

    Kemppainen, Katariina; Inkinen, Jenni; Uusitalo, Jaana; Nakari-Setälä, Tiina; Siika-aho, Matti

    2012-08-01

    Spruce bark is a source of interesting polyphenolic compounds and also a potential but little studied feedstock for sugar route biorefinery processes. Enzymatic hydrolysis and fermentation of spruce bark sugars to ethanol were studied after three different pretreatments: steam explosion (SE), hot water extraction (HWE) at 80 °C, and sequential hot water extraction and steam explosion (HWE+SE), and the recovery of different components was determined during the pretreatments. The best steam explosion conditions were 5 min at 190 °C without acid catalyst based on the efficiency of enzymatic hydrolysis of the material. However, when pectinase was included in the enzyme mixture, the hydrolysis rate and yield of HWE bark was as good as that of SE and HWE+SE barks. Ethanol was produced efficiently with the yeast Saccharomyces cerevisiae from the pretreated and hydrolysed materials suggesting the suitability of spruce bark to various lignocellulosic ethanol process concepts.

  2. Enhanced ethylene emissions from red and Norway spruce exposed to acidic mists

    SciTech Connect

    Chen, Yimin; Wellburn, A.R. )

    1989-09-01

    Acidic cloudwater is believed to cause needle injury and to decrease winter hardiness in conifers. During simulations of these adverse conditions, rates of ethylene emissions from and levels of 1-aminocyclopropane-1-carboxylic acid (ACC) in both red and Norway spruce needles increased as a result of treatment with acidic mists but amounts of 1-malonyl(amino)cyclopropane-1-carboxylic acid remained unchanged. However, release of significant quantities of ethylene by another mechanism independent of ACC was also detected from brown needles. Application of exogenous plant growth regulators such as auxin, kinetic, abscisic acid and gibberellic acid (each 0.1 millimolar) had no obvious effects on the rates of basal or stress ethylene production from Norway spruce needles. The kinetics of ethylene formation by acidic mist-stressed needles suggest that there is no active inhibitive mechanism in spruce to prevent stress ethylene being released once ACC has been formed.

  3. Optimization of ultrasound-assisted extraction of polyphenols from spruce wood bark.

    PubMed

    Ghitescu, Roxana-Elena; Volf, Irina; Carausu, Constantin; Bühlmann, Ana-Maria; Gilca, Iulian Andrei; Popa, Valentin I

    2015-01-01

    Here we describe the ultrasound-assisted extraction of the phenolic compounds from spruce wood bark and present a straight-forward experimental planning method, allowing the optimisation of the process. The effect of ethanol concentration, temperature and extraction time were evaluated through a 3(2)·2 experimental planning. The efficiency of the extraction process was appreciated based on factorial ANOVA results. The maximum extraction yield of total polyphenols (13.232mg gallic acid equivalents (GAE)/g of spruce bark tested) was obtained using a process time of 60min, an extraction temperature of 54°C and a concentration of ethanol of 70% respectively. These results indicate that an important quantity of bioactive compounds can be extracted from spruce wood bark by ultrasound assisted extraction technology.

  4. Effects of ammonium on elemental nutrition of red spruce and indicator plants grown in acid soil

    SciTech Connect

    Hoelldampf, B.; Barker, A.V. )

    1993-01-01

    Decline of high elevation red spruce forests in the northeastern United States has been related to acid rain, particularly with respect to the deposition of nitrogenous materials. Ca and Mg deficiencies may be induced by input of air-borne nitrogenous nutrients into the forest ecosystem. This research investigated the effects of N nutrition on mineral nutrition of red spruce and radish, as an indicator plant, grown in acid forest soil. Red spruce and radishes in the greenhouse were treated with complete nutrient solutions with 15 mM N supplied as 0, 3.75, 7.5, 11.25, or 15 mM NH[sub 4][sup +] with the remainder being supplied as NO[sub 3][sup [minus

  5. Pollution control enhanced spruce growth in the "Black Triangle" near the Czech-Polish border.

    PubMed

    Kolář, Tomáš; Čermák, Petr; Oulehle, Filip; Trnka, Miroslav; Štěpánek, Petr; Cudlín, Pavel; Hruška, Jakub; Büntgen, Ulf; Rybníček, Michal

    2015-12-15

    Norway spruce (Picea abies (L.) Karst.) stands in certain areas of Central Europe have experienced substantial dieback since the 1970s. Understanding the reasons for this decline and reexamining the response of forests to acid deposition reduction remains challenging because of a lack of long and well-replicated tree-ring width chronologies. Here, spruce from a subalpine area heavily affected by acid deposition (from both sulfur and nitrogen compounds) is evaluated. Tree-ring width measurements from 98 trees between 1000 and 1350m above sea level (a.s.l.) reflected significant May-July temperature signals. Since the 1970s, acid deposition has reduced the growth-climate relationship. Efficient pollution control together with a warmer but not drier climate most likely caused the increased growth of spruce stands in this region, the so-called "Black Triangle," in the 1990s.

  6. Holocene occurrence of Lophodermium piceae, a black spruce needle endophyte and possible paleoindicator of boreal forest health

    NASA Astrophysics Data System (ADS)

    Jasinski, J. P. Paul; Payette, Serge

    2007-01-01

    Holocene occurrences of conifer needle endophytes have not previously been reported. We report the fossil remains of Lophodermium piceae (Fckl.) Hoehn., a fungal endophyte of black spruce ( Picea mariana (Mill.) B.S.P.) needles, in macrofossils dating back to 8000 cal yr BP. Spruce budworm head capsules and L. piceae remains were found preceding charcoal layers delineating the transformation of four spruce-moss forest sites to spruce-lichen woodland. As L. piceae is found solely on senescent needles, its increased presence during these transformation periods likely indicates that the forests were in decline due to the spruce budworm ( Choristoneura fumiferana (Clem.)) when they burned. Future paleoecological studies incorporating needle fungi observations could be used to investigate the historical occurrence of tree disease and the role of fungi in forest health and decline.

  7. Three-dimensional crustal structure of a craton rim: Preliminary results from passive seismic imaging of the eastern Albany-Fraser Orogen, Western Australia

    NASA Astrophysics Data System (ADS)

    Sippl, Christian; Tkalčić, Hrvoje; Kennett, Brian L. N.; Spaggiari, Catherine V.; Gessner, Klaus

    2014-05-01

    Western Australia consists of two Archaean cratons (Yilgarn and Pilbara) and a number of Proterozoic orogens surrounding them that attest to past continental collisions. While the former feature seismically fast crust of average thickness (around 35 km) and a usually well defined Moho overlying a thick mantle lithospheric keel, the latter have been significantly less well studied and appear to be less uniform in terms of their crustal architecture. Thicker crust and a more fuzzy Moho are two common characteristics of these belts. The Albany-Fraser orogen, situated at the south-eastern margin of the Yilgarn craton, has been interpreted as an old suture zone from the collision of the West Australian craton (Yilgarn and Pilbara already welded together) with the Mawson craton (southern Australia and part of Antarctica today). Newer evidence, however, might point at an original rift or backarc setting of the units. It is a complex amalgam of different structures that vary significantly along its strike, featuring heavily reworked parts of the outermost Yilgarn craton as well as younger units accreted or intruded significantly later. Two major deformation stages at 1345-1260 Ma and 1214-1140 Ma have been deduced for these, the first of which has been associated with the aforementioned collision/backarc rifting itself, while the second phase is commonly interpreted as intracratonic reworking due to a major thermal event. No large-scale tectonic overprint has occurred in the region since the second deformation phase, which means that the originally emplaced units have been unusually well preserved until the present day. However, surface outcrops of rocks are very rare, so that most knowledge about extent and geometric configuration of different rock suites comes from the interpretation of magnetic and gravity data. The eastern end of the Albany-Fraser orogen, in all likelihood corresponding to the Mawson craton's westernmost edge, is hidden beneath the limestones of the

  8. Methane fluxes on pristine, drained and restored boreal spruce swamps

    NASA Astrophysics Data System (ADS)

    Koskinen, Markku; Minkkinen, Kari; Nieminen, Mika; Maanavilja, Liisa; Tuittila, Eeva-Stiina

    2014-05-01

    Successful restoration of peatlands drained for forestry means that all the processes of pristine mires are present in the restored peatlands. Methanogen communities are usually disturbed by the lowering of water table by drainage and previous studies have found only slow recovery of methane emissions on restored peatlands. We made methane flux measurements on pristine, drained and restored conditions boreal spruce swamps. Restoration measures had taken place approximately 10 years before our measurement campaign. The measurement plots on the drained and restored sites included drainage ditches and the disturbed soil beside the ditch as well as the undisturbed mid-strip area. Water table was measured from wells near the flux measurement plots. Seven sites were sampled twice per month for one growing season with eight sampling plots grouped in four locations per site in total. The locations were placed on a line perpendicular to the mire edge on the pristine sites and a drainage ditch on the drained and restored sites. The highest mean water level was recorded on the restored sites, and the lowest on the drained sites. The restored sites showed high fluxes from all measurement plots. The fluxes from the pristine and drained sites were much smaller and did not differ significantly from each other. The highest fluxes were measured from the drainage ditches on both the drained and restored sites. The pristine sites showed high relative spatio-temporal variation in the flux, partly explained by changes in the water table level. No effect of measurement plot distance from the mire edge was discernible on the pristine sites.

  9. Biosynthesis of the major tetrahydroxystilbenes in spruce, astringin and isorhapontin, proceeds via resveratrol and is enhanced by fungal infection.

    PubMed

    Hammerbacher, Almuth; Ralph, Steven G; Bohlmann, Joerg; Fenning, Trevor M; Gershenzon, Jonathan; Schmidt, Axel

    2011-10-01

    Stilbenes are dibenzyl polyphenolic compounds produced in several unrelated plant families that appear to protect against various biotic and abiotic stresses. Stilbene biosynthesis has been well described in economically important plants, such as grape (Vitis vinifera), peanut (Arachis hypogaea), and pine (Pinus species). However, very little is known about the biosynthesis and ecological role of stilbenes in spruce (Picea), an important gymnosperm tree genus in temperate and boreal forests. To investigate the biosynthesis of stilbenes in spruce, we identified two similar stilbene synthase (STS) genes in Norway spruce (Picea abies), PaSTS1 and PaSTS2, which had orthologs with high sequence identity in sitka (Picea sitchensis) and white (Picea glauca) spruce. Despite the conservation of STS sequences in these three spruce species, they differed substantially from angiosperm STSs. Several types of in vitro and in vivo assays revealed that the P. abies STSs catalyze the condensation of p-coumaroyl-coenzyme A and three molecules of malonyl-coenzyme A to yield the trihydroxystilbene resveratrol but do not directly form the dominant spruce stilbenes, which are tetrahydroxylated. However, in transgenic Norway spruce overexpressing PaSTS1, significantly higher amounts of the tetrahydroxystilbene glycosides, astringin and isorhapontin, were produced. This result suggests that the first step of stilbene biosynthesis in spruce is the formation of resveratrol, which is further modified by hydroxylation, O-methylation, and O-glucosylation to yield astringin and isorhapontin. Inoculating spruce with fungal mycelium increased STS transcript abundance and tetrahydroxystilbene glycoside production. Extracts from STS-overexpressing lines significantly inhibited fungal growth in vitro compared with extracts from control lines, suggesting that spruce stilbenes have a role in antifungal defense.

  10. Subtle structural influences on coal thickness and distribution: Examples from the Lower Broas-Stockton coal (Middle Pennsylvanian), Eastern Kentucky Coal Field, USA

    USGS Publications Warehouse

    Greb, S.F.; Eble, C.F.; Hower, J.C.

    2005-01-01

    The Lower Broas-Stockton coal is a heavily mined coal of the Central Appalachian Basin. Coal thickness, distribution, composition, and stratigraphic position were compared with basement structure, gas and oil field trends, and sequence strat- igraphic and paleoclimate interpretations to better understand the geology of the Stockton coal bed in eastern Kentucky. The thickest coal occurs south of the Warfield structural trend and east of the Paint Creek Uplift, two basement-related structures. Along the Warfield trend, coal beds in the underlying Peach Orchard coal zone locally merge with the Stockton coal to form a seam more than 3 m thick. Other areas of thick coal occur in elongate trends. Two pairs of elongate, conjugate trends in Stockton coal thickness are interpreted as regional paleofractures that influenced paleotopography and groundwater during peat accumulation. Compositional group analyses indicate that the Stockton peat infilled depressions in the paleotopography as a topogenous to soligenous mire codominated by tree ferns and lycopsid trees. Flooding from adjacent paleochannels is indicated by partings and seam splits along the margins of the mineable coal body. One or more increments of low-vitrinite coal, dominated by tree ferns and shrubby, Densosporites-producing lycopsids occur at all sample sites. Similar assemblages have been previously used to identify ombrogenous, domed mire origins for Early and Middle Pennsylvanian coals in which ash yields were less than 10%. It is difficult, however, to reconcile ombrogenous conditions with the partings in the Stockton coal in this area. Low-ash, low-vitrinite increments may have been formed in topogenous to soligenous mires with periodic drying or water-table fluctuations, rather than widespread doming. This is consistent with interpretations of increasingly seasonal paleoclimates in the late Middle and Late Pennsylvanian and fracture-influenced groundwater conditions. ??2005 Geological Society of America.

  11. Micro-chemical and micro-structural investigation of archaeological bronze weapons from the Ayanis fortress (lake Van, Eastern Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Faraldi, F.; Çilingirǒglu, A.; Angelini, E.; Riccucci, C.; De Caro, T.; Batmaz, A.; Mezzi, A.; Caschera, D.; Cortese, B.

    2013-12-01

    Bronze weapons (VII cen BC) found during the archaeological excavation of the Ayanis fortress (lake Van, eastern Anatolia, Turkey) are investigated in order to determine their chemical composition and metallurgical features as well as to identify the micro-chemical and micro-structural nature of the corrosion products grown during long-term burial. Small fragments were sampled from the artefacts and analysed by means of the combined use of optical microscopy (OM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results show that the bronze artefacts have been manufactured by using alloys with a controlled and refined chemical composition demonstrating the high level metallurgical competence and skill of the Urartian craftsmen and artists. Furthermore, the micro-structural and metallurgical investigations evidence the presence of equiaxed grains in the matrix, indicating that the artefact were produced by repeated cycles of mechanical shaping and thermal annealing treatments to restore the alloy ductility. From the degradation point of view, the results show the structures and the chemical composition of the stratified corrosion layers (i.e. the patina) where the copper or tin depletion phenomenon is commonly observed with the surface enrichment of some elements coming from the burial soil, mainly Cl, which is related to the high concentration of chlorides in the Ayanis soil. The results reveal also that another source of degradation is the inter-granular corrosion phenomenon likely increased by the metallurgical features of the alloys caused by the high temperature manufacturing process that induces crystallisation and segregation phenomena along the grain boundaries.

  12. Mega-scale Moho relief and the structure of the lithosphere on the eastern flank of the Viking Graben, offshore southwestern Norway

    NASA Astrophysics Data System (ADS)

    Gabrielsen, Roy H.; Fossen, Haakon; Faleide, Jan Inge; Hurich, Charles A.

    2015-05-01

    The International Lithosphere Project deep reflection seismic survey in the Norwegian sector of the North Sea has been reprocessed, particularly focusing on the deep crust, the reflection Moho, and the upper mantle. The data display shifting reflection patterns of the crust and the upper mantle parallel to the eastern margin of the Viking Graben. In the upper crust, which is mainly seismically transparent by the processing techniques utilized here, large-scale structural features like detachment shear zones and master faults can be identified. Several of the major onshore faults and shear zones match seismic features in the seismic lines. Many of these structures acted as extensional shear zones in the Devonian. The middle crust is of variable reflectivity, whereas the lower crust is generally strongly reflective and is particularly so in the southern domain. The reflection Moho is identified throughout the study area but is of variable character. The presence of a S(E) dipping structure (Hardanger Moho Offset) that displaces the Moho by approximately 10 km, extends deep into the mantle (below the 50 km line depth), is positioned where the shallower Hardangerfjord Shear Zone, which flattens on the level of the middle crust, is situated. The Hardangerfjord Shear Zone/Hardanger Moho Offset-system coincides with change of the crustal thickness (depth to Moho), a change that also coincides with the transition from thin- to thick-skinned Caledonian deformation. Intramantle reflections are common in the study area, some of which are interpreted as shear zones, whereas others most likely represent magmatic intrusions.

  13. Influence of strain rate and temperature on the radial compression behavior of wet spruce

    SciTech Connect

    Uhmeier, A.; Salmen, L.

    1995-12-31

    In this study, the influences of moisture content, density, strain rate and temperature on the mechanical response of spruce compressed radially to 50% strain were investigated. Regression models were obtained for the plateau stress, energy absorption, plastic strain and reduction of plateau stress after the first compression. Temperature and strain rate had a great influence on the mechanical behaviour of spruce. It was found that lumen water had a significant effect on the deformation process at high strain rates. The reduction in plateau stress after one compression was about 30-55%, which might increase the collapsibility of the wood fibers.

  14. To reactivate or not to reactivate: nature and varied behavior of structural inheritance in the Proterozoic basement of the Eastern Colorado mineral belt over 1.7 billion years of earth history

    USGS Publications Warehouse

    Caine, Jonathan Saul; Ridley, John; Wessel, Zachary R.

    2010-01-01

    The eastern central Front Range of the Rocky Mountains in Colorado has long been a region of geologic interest because of Laramide-age hydrothermal polymetallic vein-related ores. The region is characterized by a well-exposed array of geologic structures associated with ductile and brittle deformation, which record crustal strain over 1.7 billion years of continental growth and evolution. The mineralized areas lie along a broad linear zone termed the Colorado Mineral Belt. This lineament has commonly been interpreted as following a fundamental boundary, such as a suture zone, in the North American Proterozoic crust that acted as a persistent zone of weakness localizing the emplacement of magmas and associated hydrothermal fluid flow. However, the details on the controls of the location, orientation, kinematics, density, permeability, and relative strength of various geological structures and their specific relationships to mineral deposit formation are not related to Proterozoic ancestry in a simple manner. The objectives of this field trip are to show key localities typical of the various types of structures present, show recently compiled and new data, offer alternative conceptual models, and foster dialogue. Topics to be discussed include: (1) structural history of the eastern Front Range; (2) characteristics, kinematics, orientations, and age of ductile and brittle structures and how they may or may not relate to one another and mineral deposit permeability; and (3) characteristics, localization, and evolution of the metal and non–metal-bearing hydrothermal systems in the eastern Colorado Mineral Belt.

  15. Structure of metavolcanic and metasedimentary rocks in the Matterhorn-Twin Peaks area, Saddlebag Lake pendant, eastern Sierra Nevada, California

    SciTech Connect

    Lahren, M.M.; Schweickert, R.A. . Dept. of Geological Sciences)

    1993-04-01

    Recent structural mapping shows that the rocks in the Matterhorn-Twin Peaks area comprise parts of seven east-dipping and east-facing thrust sheets. These sheets and their bounding thrusts all appear to dip beneath the structurally higher, Glenberry Lake thrust sheet, and are intruded discordantly in Spiller, Cattle, Horse canyons by the 86-Ma Cathedral Peak Granodiorite of the Tuolumne Intrusive Suite (TIS). The lowest exposed sheet contains rocks that probably correlate with the Upper Triassic and Lower Jurassic Koip sequence. The overlying six sheets contain a distinctive assemblage of metamorphosed calcareous sandstone, siltstone, mudstone, limestone, and interbedded silicic tuffs of the Horse Canyon sequence, possibly of Middle Jurassic age. Thrust faults expose mylonitic and schistose metavolcanic rocks, and the two lowest are marked by slices of periodotite up to several tens of meters in length. Locally, conglomerates with clasts of peridotite, quartzite, and metavolcanic rocks are associated with the peridotite slices. A sill-like body of granitic orthogneiss occurs along one of the thrusts. Stretching lineations in the most intensely deformed rocks plunge steeply to the east, suggesting dominantly dip slip displacement. The origin(s) of the peridotite slices are enigmatic, but the authors provisionally interpret the peridotite to have been intermittently exposed at the surface during thrusting, and the conglomerates to have been thrust-derived. Age of thrusting is unknown, but probably was between Middle Jurassic and Middle Cretaceous. The structure of this area argues against major deformation due to intrusion or return flow along the margins of the TIS.

  16. Studying Crust and Upper Mantle Structure in Eastern Canada with High-Resolution Teleseismic Receiver Function Analysis

    NASA Astrophysics Data System (ADS)

    Wang, B.; Darbyshire, F. A.; Gao, S. S.

    2012-12-01

    Teleseismic receiver function (RF) analysis is an important technique that is widely used in studying the Earth's crust and upper mantle structure. A critical step of this technique is the RF calculation which is an unstable deconvolution procedure. A spline-based RF calculation method is developed, and it is demonstrated that the stacked spline-based RFs have higher resolution than the stacked RFs calculated with the water-level spectral division and iterative deconvolution methods. The better RFs calculated with the spline method lead to improved determination of the optimal Moho depths and Vp/Vs ratios with greater resolution and clarity, albeit compatible optimal Moho depths and Vp/Vs ratios are obtained by employing all three RF calculation methods. In contrast to the iterative deconvolution and water-level spectral division methods, there is less extensive strap of high values on the H-k analysis image and the maximum peak is substantially sharper for the spline method. The broadband seismogram data are acquired at 9 stations of the UQAM / POLARIS Seismograph Network in Quebec in the Superior Province and Greenville Province of the Canadian Shield. Nice PmS converted phase is clearly seen for all the stations. The crustal thickness ranges from 32.5 km to 38.9 km, and the Vp/Vs ratio from 1.68 to 1.83. Several stations show excellent coherent signals of the converted phases on both the radial and tangential RFs over a range of backazimuthal variations. This would indicate evidence for intra-crustal and significant 3D and/or anisotropic structure. More detailed forward and inverse modeling of the lithospheric structure and comparison with other geological and geophysical data and information are in progress.

  17. A reconnaissance space sensing investigation of crustal structure for a strip from the eastern Sierra Nevada to the Colorado Plateau

    NASA Technical Reports Server (NTRS)

    Liggett, M. A.; Childs, J. F.

    1973-01-01

    The author has identified the following significant results. Research progress in applications of ERTS-1 MSS imagery to study of Basin-Range tectonics is summarized. Field reconnaissance of ERTS-1 image anomalies has resulted in recognition of previously unreported fault zones and regional structural control of volcanic and plutonic activity. Nimbus, Apollo 9, X-15, U-2, and SIAR imagery are discussed with specific applications, and methods of image enhancement and analysis employed in the research are summarized. Field areas studied and methods employed in geologic field work are outlined.

  18. Broadband Magnetotelluric Investigations of Crustal Resistivity Structure in North-Eastern Alberta: Implications for Engineered Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Liddell, M. V.; Unsworth, M. J.; Nieuwenhuis, G.

    2013-12-01

    Greenhouse gas emissions from hydrocarbon consumption produce profound changes in the global climate, and the implementation of alternative energy sources is needed. The oilsands industry in Alberta (Canada) is a major producer of greenhouse gases as natural gas is burnt to produce the heat required to extract and process bitumen. Geothermal energy could be utilized to provide this necessary heat and has the potential to reduce both financial costs and environmental impacts of the oilsands industry. In order to determine the geothermal potential the details of the reservoir must be understood. Conventional hydrothermal reservoirs have been detected using geophysical techniques such as magnetotellurics (MT) which measures the electrical conductivity of the Earth. However, in Northern Alberta the geothermal gradient is relatively low, and heat must be extracted from deep inside the basement rocks using Engineered Geothermal Systems (EGS) and therefore an alternative exploration technique is required. MT can be useful in this context as it can detect fracture zones and regions of elevated porosity. MT data were recorded near Fort McMurray with the goal of determining the geothermal potential by understanding the crustal resistivity structure beneath the Athabasca Oilsands. The MT data are being used to locate targets of significance for geothermal exploration such as regions of low resistivity in the basement rocks which can relate to in situ fluids or fracture zones which can facilitate efficient heat extraction or het transport. A total of 93 stations were collected ~500m apart on two profiles stretching 30 and 20km respectively. Signals were recorded using Phoenix Geophysics V5-2000 systems over frequency bands from 1000 to 0.001 Hz, corresponding to depths of penetration approximately 50m to 50km. Groom-Bailey tensor decomposition and phase tensor analysis shows a well defined geoelectric strike direction that varied along the profile from N60°E to N45

  19. Paleoseismology of the 1966 Varto Earthquake (Ms 6.8) and Structure of the Varto Fault Zone, Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Isik, V.; Caglayan, A.; Saber, R.; Yesilyurt, N.

    2014-12-01

    Turkey is a region of active faulting and contains several strike-slip fault zones, which have generated both historical and recent large earthquakes. Two active fault zones in Turkey, the North Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ), divide the area into the Anatolian micro-plate accommodating WSW-directed movement. The southeastern continuation of the NAFZ is often referred to the Varto Fault Zone (VFZ). The VFZ cuts mainly Pliocene volcano-sedimentary units and/or Quaternary deposits and is characterized by multiple fault strands and multiple, closely spaced, active seismogenic zones. Fault motions in the zone are primarily right-lateral, with a subordinate component of NNW-SSE shortening. Study area is Varto region in which indications of active faulting are very well preserved. We recognized three coseismic ruptures from five trench exposures. It is referred to these as events 1 (youngest) through 3 (oldest). The best evidence of event 3 comes from fault traces and its upward terminations. The major components of this fault are fault core and damage zone. The fault is not just one plane of discontinuity and bifurcates and creates additional slip surfaces, which propagate out of the plane of the original fault. Event 2 and event 1, referring to 1946 and 1966 earthquakes, are characterized primarily by discrete, regularly spaced normal faults with and 55-80 cm and 105-270 cm throws, respectively and geometry of growth strata. The VFZ in the study area include typical structures of strike-slip fault zone. It forms a number of parallel and slightly sub-parallel strands striking N50°-72°W including contractional and extensional brittle structures. Several meters to tens of meters wavelength active folds with ENE-WSW and WNW-ESE trending fold axis. These folds deform the Plio-Quaternary units and show classic asymmetry associated with both a south- and north-vergent fault propagation fold. Meso-scale normal faults are also well

  20. Crustal structure of the eastern Algerian continental margin and adjacent deep basin: implications for late Cenozoic geodynamic evolution of the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Bouyahiaoui, B.; Sage, F.; Abtout, A.; Klingelhoefer, F.; Yelles-Chaouche, K.; Schnürle, P.; Marok, A.; Déverchère, J.; Arab, M.; Galve, A.; Collot, J. Y.

    2015-06-01

    We determine the deep structure of the eastern Algerian basin and its southern margin in the Annaba region (easternmost Algeria), to better constrain the plate kinematic reconstruction in this region. This study is based on new geophysical data collected during the SPIRAL cruise in 2009, which included a wide-angle, 240-km-long, onshore-offshore seismic profile, multichannel seismic reflection lines and gravity and magnetic data, complemented by the available geophysical data for the study area. The analysis and modelling of the wide-angle seismic data including refracted and reflected arrival travel times, and integrated with the multichannel seismic reflection lines, reveal the detailed structure of an ocean-to-continent transition. In the deep basin, there is an ˜5.5-km-thick oceanic crust that is composed of two layers. The upper layer of the crust is defined by a high velocity gradient and P-wave velocities between 4.8 and 6.0 km s-1, from the top to the bottom. The lower crust is defined by a lower velocity gradient and P-wave velocity between 6.0 and 7.1 km s-1. The Poisson ratio in the lower crust deduced from S-wave modelling is 0.28, which indicates that the lower crust is composed mainly of gabbros. Below the continental edge, a typical continental crust with P-wave velocities between 5.2 and 7.0 km s-1, from the top to the bottom, shows a gradual seaward thinning of ˜15 km over an ˜35-km distance. This thinning is regularly distributed between the upper and lower crusts, and it characterizes a rifted margin, which has resulted from backarc extension at the rear of the Kabylian block, here represented by the Edough Massif at the shoreline. Above the continental basement, an ˜2-km-thick, pre-Messinian sediment layer with a complex internal structure is interpreted as allochthonous nappes of flysch backthrusted on the margin during the collision of Kabylia with the African margin. The crustal structure, moreover, provides evidence for Miocene

  1. A reconnaissance space sensing investigation of the crustal structure for a strip from the eastern Sierra Nevada to the Colorado Plateau: April 1971

    NASA Technical Reports Server (NTRS)

    Bechtold, I. C. (Principal Investigator); Liggett, M. A.

    1972-01-01

    The author has identified the following significant results. An area of anomalous linear topographic grain and color expressions was recognized in Apollo 9 and ERTS-1 imagery along the Colorado River of northwestern Arizona and southern Nevada. Field reconnaissance and analysis of U-2 photography has shown the anomaly to be a zone of north to north-northwest trending dike swarms and associated granitic plutons. The dikes vary in composition from rhyolite to diabase, with an average composition nearer rhyolite. Shearing and displacement of host rocks along dikes suggest dike emplacement along active fault zones. Post-dike deformation has resulted in shearing and complex normal faulting along a similar north-south trend. The epizonal plutonism and volcanism of this north-south belt appears to represent a structurally controlled volcanogenic province which ends abruptly in the vicinity of Lake Mead at a probable eastern extension of the Las Vegas Shear Zone. The magnitude and chronology of extensional faulting and plutonism recognized in the north-south zone, support the hypothesis that the Las Vegas Shear Zone is a transform fault separating two areas of crustal spreading.

  2. Change in atmospheric deposition during last half century and its impact on lichen community structure in Eastern Himalaya

    NASA Astrophysics Data System (ADS)

    Bajpai, Rajesh; Mishra, Seema; Dwivedi, Sanjay; Upreti, Dalip Kumar

    2016-08-01

    Climatic fluctuations largely affects species turnover and cause major shifts of terrestrial ecosystem. In the present study the five decade old herbarium specimens of lichens were compared with recent collection from Darjeeling district with respect to elements, PAHs accumulation and carbon isotope composition (δ13C) to explore the changes in climatic conditions and its impact on lichen flora. The δ13C has increased in recent specimens which is in contrast to the assumption that anthropogenic emission leads to δ13C depletion in air and increased carbon discrimination in flora. Study clearly demonstrated an increase in anthropogenic pollution and drastic decrease in precipitation while temperature showed abrupt changes during the past five decades resulting in significant change in lichen community structure. The Usneoid and Pertusorioid communities increased, while Physcioid and Cyanophycean decreased, drastically. Lobarian abolished from the study area, however, Calcicoid has been introduced in the recent past. Probably, post-industrial revolution, the abrupt changes in the environment has influenced CO2 diffusion and/C fixation of (lower) plants either as an adaptation strategy or due to toxicity of pollutants. Thus, the short term studies (≤5 decades) might reflect recent micro-environmental condition and lichen community structure can be used as model to study the global climate change.

  3. Change in atmospheric deposition during last half century and its impact on lichen community structure in Eastern Himalaya

    PubMed Central

    Bajpai, Rajesh; Mishra, Seema; Dwivedi, Sanjay; Upreti, Dalip Kumar

    2016-01-01

    Climatic fluctuations largely affects species turnover and cause major shifts of terrestrial ecosystem. In the present study the five decade old herbarium specimens of lichens were compared with recent collection from Darjeeling district with respect to elements, PAHs accumulation and carbon isotope composition (δ13C) to explore the changes in climatic conditions and its impact on lichen flora. Th