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Sample records for del musgo sphagnum

  1. VARIACIÓN DEL CONTENIDO DE AZÚCARES TOTALES Y AZÚCARES REDUCTORES EN EL MUSGO Pleurozium schreberi (HYLOCOMIACEAE BAJO CONDICIONES DE DÉFICIT HÍDRICO

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    LUIS CARLOS MONTENEGRO

    2012-09-01

    Full Text Available Los briófitos por su simplicidad estructural se ven expuestos a estrés hídrico con facilidad,por lo que presentan mecanismos fisiológicos y bioquímicos que les permita sobrevivir.En el presente trabajo se evaluó la variación del contenido de azúcares totales solubles yazúcares reductores en relación con el contenido hídrico relativo, en Pleurozium schrebericuando se enfrenta a contenidos hídricos bajos en el Páramo de Chingaza (Colombia ybajo condiciones simuladas de déficit hídrico en laboratorio. Se encontró que los azúcarestotales aumentan cuando la planta se deshidrata y vuelve a su contenido normal cuandoel musgo se rehidra, esto puede ser interpretado como un posible mecanismo de ajusteosmótico de la célula y osmoprotección del contenido celular y de la estructura celular.Los azúcares reductores no presentaron variación significativa, mostrando que losmonosacáridos no tienen una función protectora durante la deshidratación.

  2. MUSGOS COMO BIOINDICADORES DE METAIS PESADOS NO AMBIENTE

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    Eliane Ferreira de SOUZA

    2017-12-01

    Full Text Available Recentemente, inúmeras pesquisas envolvendo degradação ambiental oriunda das poluições atmosférica, terrestre e aquática, tem como foco o uso de animais ou vegetais, que apresentem respostas no sentido de controlar e indicar o nível de deterioração nos ambientes afetados por ações antrópicas. Dentre os organismos indicadores denominados biomonitores, estão os musgos do Filo Bryophyta responsáveis por respostas significativas frente aos impactos gerados pelo descarte indevido de substâncias, que contêm em sua composição metais pesados. Os metais pesados são considerados um dos principais poluentes que afetam os recursos naturais. Geralmente, os mesmos são oriundos de técnicas agrícolas ou mecanismos urbanos que produzem resíduos. Nesta linha, o presente estudo de revisão visa relacionar, principalmente, os efeitos da poluição dos recursos naturais a partir do uso de musgos como bioindicadores de traços metálicos no ambiente.

  3. AMENAZAS A LA CONSERVACIÓN DE LAS ESPECIES DE MUSGOS Y LÍQUENES EN COLOMBIA -UNA APROXIMACIÓN INICIAL

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    AGUIRRE-C. JAIME

    2007-12-01

    Full Text Available Las amenazas sobre las poblaciones naturales de musgos y líquenes se evaluaron con baseen particularidades de sus rasgos corológicos, en la calidad del hábitat y en las posibilidadesde transformación y aún de desaparición de porciones considerables del espacio físicoen las regiones naturales de Colombia. En la categorización del riesgo-amenaza, sesiguieron parcialmente los lineamientos metodológicos de la Unión Internacional parala Conservación de la Naturaleza (UICN incluyendo las categorías en peligro crítico(CR, en alto riesgo de extinción (EN, vulnerable (VU y casi amenazado (NT. Losresultados de esta aproximación inicial permitieron calificar bajo algún tipo de amenazaen sus poblaciones naturales a 388 especies de 145 géneros y 46 familias de musgos;Pottiaceae y Pilotrichaceae son las familias que tienen especies amenazadas en la mayoríade las regiones naturales y en los ramales cordilleranos. Según categorías de amenaza, enpeligro crítico (CR se calificaron a 125 especies; en peligro (EN a 21, como vulnerables(VU se calificaron a 173 especies y en la condición casi amenazado (NT a 69 especies.Sphagnaceae, Pilotrichaceae, Orthotrichaceae y Pottiaceae presentaron especies en todaslas categorías de amenaza. En la Amazonia hay 24 especies de musgos con algún tipo deamenazas y la categoría con mayor representación es vulnerable (VU con doce especies;en el Chocó biogeográfico 15 especies sufren algún tipo de amenaza y la categoría conmayor significancia es vulnerable (VU con siete especies. En la región Caribe, en elmacizo montañoso de la Sierra Nevada de Santa Marta 15 especies figuraron comoamenazadas y la condición más frecuente fue en estado crítico (CR con ocho especies.En el sistema montañoso (gradiente cordillerano se calificaron a 285 especies bajo algúntipo de amenaza; Pottiaceae, Pilotrichaceae, Sematophyllaceae e Hypnaceae presentaronespecies amenazadas a lo largo del gradiente altitudinal. En

  4. pH Lowering Ability of Sphagnum.

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    Glime, Janice M.; Li, Yenhung

    1998-01-01

    States that the ecological role of Sphagnum species in peatlands is enormous. Presents a cation exchange experiment and background information on the characteristics and economic importance of Sphagnum. Contains 42 references. (DDR)

  5. Ecophysiological adaptations of coexisting Sphagnum mosses

    OpenAIRE

    HÁJEK, Tomáš

    2008-01-01

    I studied ecological and physiological adaptations of peat misses (Sphagnum species) coexisting along the environmental gradients in mires. Production, decomposition, water relations, desiccation tolerance and nutrient economy of Sphagnum species were evaluates along the hummock-hollow gradient of water table, while the light adaptations were assessed in an open and forested mire

  6. Evaporation from a sphagnum moss surface

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    D.S. Nichols; J.M. Brown

    1980-01-01

    Peat cores, 45 cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss surface was greater than that from a free-water surface. Evaporation from the moss increased...

  7. Restoration techniques for Sphagnum-dominated peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Ferland, C.; Rochefort, L. [Laval University, Sainte-Foy, PQ (Canada). Department of Phytology

    1997-07-01

    After peat harvesting, peat mosses do not usually recolonize the abandoned site. The purpose of this study is to develop techniques for restoring peatlands. Sphagnum diaspores from natural peatlands were introduced to exploited peatlands. The influence of microrelief, of planting companion species with the Sphagnum, and of light phosphorus fertilization on establishment of a peat moss carpet are examined. The results show that Sphagnum diaspores can be reintroduced on bare peat surfaces. The restoration method is combined with techniques to improve substrata moisture conditions, such as creation of surface roughness and the use of companion plant species. 32 refs., 6 figs., 3 tabs.

  8. Sphagnum farming on cut-over bog in NW Germany: Long-term studies on Sphagnum growth

    OpenAIRE

    G. Gaudig; M. Krebs; H. Joosten

    2017-01-01

    Sphagnum farming allows sustainable and climate-friendly land use on bogs while producing a renewable substitute for peat in horticultural growing media. We studied Sphagnum productivity on an experimental Sphagnum culture established on a cut-over bog in Germany with strongly humified peat at the surface. Preparation of the site included levelling of the peat surface, construction of an irrigation system, spreading of Sphagnum papillosum fragments, covering them with straw, and finally rewet...

  9. Sphagnum moss disperses spores with vortex rings.

    Science.gov (United States)

    Whitaker, Dwight L; Edwards, Joan

    2010-07-23

    Sphagnum spores, which have low terminal velocities, are carried by turbulent wind currents to establish colonies many kilometers away. However, spores that are easily kept aloft are also rapidly decelerated in still air; thus, dispersal range depends strongly on release height. Vascular plants grow tall to lift spores into sufficient wind currents for dispersal, but nonvascular plants such as Sphagnum cannot grow sufficiently high. High-speed videos show that exploding capsules of Sphagnum generate vortex rings to efficiently carry spores high enough to be dispersed by turbulent air currents. Spores launched ballistically at similar speeds through still air would travel a few millimeters and not easily reach turbulent air. Vortex rings are used by animals; here, we report vortex rings generated by plants.

  10. Nitrogen deposition does not enhance Sphagnum decomposition.

    Science.gov (United States)

    Manninen, S; Kivimäki, S; Leith, I D; Leeson, S R; Sheppard, L J

    2016-11-15

    Long-term additions of nitrogen (N) to peatlands have altered bryophyte growth, species dominance, N content in peat and peat water, and often resulted in enhanced Sphagnum decomposition rate. However, these results have mainly been derived from experiments in which N was applied as ammonium nitrate (NH4NO3), neglecting the fact that in polluted areas, wet deposition may be dominated either by NO3(-) or NH4(+). We studied effects of elevated wet deposition of NO3(-) vs. NH4(+) alone (8 or 56kgNha(-1)yr(-1) over and above the background of 8kgNha(-1)yr(-1) for 5 to 11years) or combined with phosphorus (P) and potassium (K) on Sphagnum quality for decomposers, mass loss, and associated changes in hummock pore water in an ombrotrophic bog (Whim). Adding N, especially as NH4(+), increased N concentration in Sphagnum, but did not enhance mass loss from Sphagnum. Mass loss seemed to depend mainly on moss species and climatic factors. Only high applications of N affected hummock pore water chemistry, which varied considerably over time. Overall, C and N cycling in this N treated bog appeared to be decoupled. We conclude that moss species, seasonal and annual variation in climatic factors, direct negative effects of N (NH4(+) toxicity) on Sphagnum production, and indirect effects (increase in pH and changes in plant species dominance under elevated NO3(-) alone and with PK) drive Sphagnum decomposition and hummock C and N dynamics at Whim. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Growth of sphagnum: methods of measurement

    Energy Technology Data Exchange (ETDEWEB)

    Clymo, R S

    1970-01-01

    The results presented here show that the growth of sphagnum is at least comparable with other communities from the same area. It seems desirable to know more about the field microenvironment and about the response of the plants. It is not possible, for example, to account satisfactorily for such obvious features of bog topography as hummocks and pools.

  12. Sphagnum bogs of Kelantan, Peninsular Malaysia

    NARCIS (Netherlands)

    Yao, T.L.; Kamarudin, S.; Chew, M.Y.; Kiew, R.

    2009-01-01

    Sphagnum bog, a unique plant community for Peninsular Malaysia was encountered on Padang Ragut, Kelantan. Its topographical features and flora are described, and compared with padang and upper montane floras. It is postulated that the community is derived from upper montane forest and is the result

  13. [Methanotrophic bacteria of acid sphagnum bogs].

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    Dedysh, S N

    2002-01-01

    Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

  14. Sphagnum growth and ecophysiology during mire succession.

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    Laine, Anna M; Juurola, Eija; Hájek, Tomáš; Tuittila, Eeva-Stiina

    2011-12-01

    Sphagnum mosses are widespread in areas where mires exist and constitute a globally important carbon sink. Their ecophysiology is known to be related to the water level, but very little is currently known about the successional trend in Sphagnum. We hypothesized that moss species follow the known vascular plant growth strategy along the successional gradient (i.e., decrease in production and maximal photosynthesis while succession proceeds). To address this hypothesis, we studied links between the growth and related ecophysiological processes of Sphagnum mosses from a time-since-initiation chronosequence of five wetlands. We quantified the rates of increase in biomass and length of different Sphagnum species in relation to their CO(2) assimilation rates, their photosynthetic light reaction efficiencies, and their physiological states, as measured by the chlorophyll fluorescence method. In agreement with our hypothesis, increase in biomass and CO(2) exchange rate of Sphagnum mosses decreased along the successional gradient, following the tactics of more intensely studied vascular plants. Mosses at the young and old ends of the chronosequence showed indications of downregulation, measured as a low ratio between variable and maximum fluorescence (F(v)/F(m)). Our study divided the species into three groups; pioneer species, hollow species, and ombrotrophic hummock formers. The pioneer species S. fimbriatum is a ruderal plant that occurred at the first sites along the chronosequence, which were characterized by low stress but high disturbance. Hollow species are competitive plants that occurred at sites with low stress and low disturbance (i.e., in the wet depressions in the middle and at the old end of the chronosequence). Ombrotrophic hummock species are stress-tolerant plants that occurred at sites with high stress and low disturbance (i.e., at the old end of the chronosequence). The three groups along the mire successional gradient appeared to be somewhat analogous

  15. Symbiosis revisited : Phosphorus and acid buffering stimulate N2 fixation but not Sphagnum growth

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    Van Den Elzen, Eva; Kox, Martine A R; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S M; Ettwig, Katharina F.; Lamers, Leon P M

    2017-01-01

    In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands,

  16. Sphagnum farming on cut-over bog in NW Germany: Long-term studies on Sphagnum growth

    Directory of Open Access Journals (Sweden)

    G. Gaudig

    2017-05-01

    Full Text Available Sphagnum farming allows sustainable and climate-friendly land use on bogs while producing a renewable substitute for peat in horticultural growing media. We studied Sphagnum productivity on an experimental Sphagnum culture established on a cut-over bog in Germany with strongly humified peat at the surface. Preparation of the site included levelling of the peat surface, construction of an irrigation system, spreading of Sphagnum papillosum fragments, covering them with straw, and finally rewetting. Provided there was an adequate (95 % initial cover of Sphagnum fragments, the most relevant variables for Sphagnum productivity were found to be water supply and regular mowing of vascular plants. As long as sufficient water was supplied, the dry biomass accumulation of the established Sphagnum lawn remained high, reaching 3.7 t ha-1 yr-1 between 2007 and 2011. Annual dry Sphagnum biomass productivity over the period 2010–2011 was up to 6.9 t ha-1. During periods when high water table could not be maintained, substantial decomposition of the previously accumulated biomass occurred. After nine years the net accumulated dry mass per hectare was on average 19.5 t of pure Sphagnum and 0.7 t of subsurface vascular-plant biomass. Nitrogen deposition in the study region is apparently sufficient to support fast Sphagnum growth, whereas phosphorus and potassium may be limiting.

  17. Sphagnum farming in Germany – a review of progress

    OpenAIRE

    G. Gaudig; F. Fengler; M. Krebs; A. Prager; J. Schulz; S. Wichmann; H. Joosten

    2014-01-01

    In ombrotrophic, nutrient-poor peatlands, the cultivation of peatmoss (Sphagnum spp.) is a promising paludiculture option. Since 2001 we have been studying peatmoss cultivation (‘Sphagnum farming’) in greenhouse and field experiments, paying special attention to propagation, propagule storage, establishment, productivity and regeneration. Our studies show that Sphagnum farming in Germany may provide a sustainable high-quality alternative to fossil white peat as a raw material for horticultural...

  18. Sphagnum farming in Germany – a review of progress

    Directory of Open Access Journals (Sweden)

    G. Gaudig

    2014-02-01

    Full Text Available In ombrotrophic, nutrient-poor peatlands, the cultivation of peatmoss (Sphagnum spp. is a promising paludiculture option. Since 2001 we have been studying peatmoss cultivation (‘Sphagnum farming’ in greenhouse and field experiments, paying special attention to propagation, propagule storage, establishment, productivity and regeneration. Our studies show that Sphagnum farming in Germany may provide a sustainable high-quality alternative to fossil white peat as a raw material for horticultural growing media. Sphagnum farming is, furthermore, a climate-friendly and sustainable land use option for abandoned cut-over bogs and degraded bog grassland.

  19. Láminas para el Laboratorio de Botánica General (I): algas, hongos, hepáticas, musgos & helechos

    OpenAIRE

    Cubas, Paloma

    2012-01-01

    En esta primera parte de la obra, se presentan imágenes macroscópicas y microscópicas de algas, hongos, musgos, hepáticas y helechos, y de las estructuras básicas que los estudiantes de un curso de introducción a la botánica deben observar y saber interpretar. Las imágenes macroscópicas presentan detalles que se pueden ver fácilmente con una lupa binocular sencilla, y las de microscopía óptica se han obtenido con técnicas simples, montando preparaciones en agua, realizando cortes a mano alzad...

  20. A comparative study of lipids in Sphagnum species

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    Sinninghe Damsté, J.S.; Baas, M.; Pancost, R.D.; Geel, B. van

    2000-01-01

    The free lipid compositions of twelve species of Sphagnum were determined by capillary gas chromatography/mass spectrometry as part of a study to identify characteristic lipids for Sphagnum in peat bogs. Complex mixtures of lipids, comprised of C28 C29 sterols, C30 triterpenoids, C16 C30 fatty

  1. The Sphagnum microbiome: new insights from an ancient plant lineage

    Science.gov (United States)

    Joel E. Kostka; David J. Weston; Jennifer B. Glass; Erik A. Lilleskov; A. Jonathan Shaw; Merritt Turetsky

    2016-01-01

    Peat mosses of the genus Sphagnum play a major role in global carbon storage and dominate many northern peatland ecosystems, which are currently being subjected to some of the most rapid climate changes on Earth.Arapidly expanding database indicates that a diverse community of microorganisms is intimately associated with Sphagnum...

  2. Organellar phylogenomics of an emerging model system: Sphagnum (peatmoss).

    Science.gov (United States)

    Jonathan Shaw, A; Devos, Nicolas; Liu, Yang; Cox, Cymon J; Goffinet, Bernard; Flatberg, Kjell Ivar; Shaw, Blanka

    2016-08-01

    Sphagnum-dominated peatlands contain approx. 30 % of the terrestrial carbon pool in the form of partially decomposed plant material (peat), and, as a consequence, Sphagnum is currently a focus of studies on biogeochemistry and control of global climate. Sphagnum species differ in ecologically important traits that scale up to impact ecosystem function, and sequencing of the genome from selected Sphagnum species is currently underway. As an emerging model system, these resources for Sphagnum will facilitate linking nucleotide variation to plant functional traits, and through those traits to ecosystem processes. A solid phylogenetic framework for Sphagnum is crucial to comparative analyses of species-specific traits, but relationships among major clades within Sphagnum have been recalcitrant to resolution because the genus underwent a rapid radiation. Herein a well-supported hypothesis for phylogenetic relationships among major clades within Sphagnum based on organellar genome sequences (plastid, mitochondrial) is provided. We obtained nucleotide sequences (273 753 nucleotides in total) from the two organellar genomes from 38 species (including three outgroups). Phylogenetic analyses were conducted using a variety of methods applied to nucleotide and amino acid sequences. The Sphagnum phylogeny was rooted with sequences from the related Sphagnopsida genera, Eosphagnum and Flatbergium Phylogenetic analyses of the data converge on the following subgeneric relationships: (Rigida (((Subsecunda) (Cuspidata)) ((Sphagnum) (Acutifolia))). All relationships were strongly supported. Species in the two major clades (i.e. Subsecunda + Cuspidata and Sphagnum + Acutifolia), which include >90 % of all Sphagnum species, differ in ecological niches and these differences correlate with other functional traits that impact biogeochemical cycling. Mitochondrial intron presence/absence are variable among species and genera of the Sphagnopsida. Two new nomenclatural combinations are made

  3. Greenhouse gas balance of an establishing Sphagnum culture on a former bog grassland in Germany

    OpenAIRE

    A. Günther; G. Jurasinski; K. Albrecht; G. Gaudig; M. Krebs; S. Glatzel

    2017-01-01

    The cultivation of Sphagnum mosses on re-wetted peat bogs for use in horticulture is a new land use strategy. We provide the first greenhouse gas balances for a field-scale Sphagnum farming experiment on former bog grassland, in its establishment phase. Over two years we used closed chambers to make measurements of GHG exchange on production strips of Sphagnum palustre L. and Sphagnum papillosum Lindb. and on irrigation ditches. Methane fluxes of both Sphagnum species showed a significant dec...

  4. The Sphagnum microbiome: new insights from an ancient plant lineage.

    Science.gov (United States)

    Kostka, Joel E; Weston, David J; Glass, Jennifer B; Lilleskov, Erik A; Shaw, A Jonathan; Turetsky, Merritt R

    2016-07-01

    57 I. 57 II. 58 III. 59 IV. 59 V. 61 VI. 62 63 References 63 SUMMARY: Peat mosses of the genus Sphagnum play a major role in global carbon storage and dominate many northern peatland ecosystems, which are currently being subjected to some of the most rapid climate changes on Earth. A rapidly expanding database indicates that a diverse community of microorganisms is intimately associated with Sphagnum, inhabiting the tissues and surface of the plant. Here we summarize the current state of knowledge regarding the Sphagnum microbiome and provide a perspective for future research directions. Although the majority of the microbiome remains uncultivated and its metabolic capabilities uncharacterized, prokaryotes and fungi have the potential to act as mutualists, symbionts, or antagonists of Sphagnum. For example, methanotrophic and nitrogen-fixing bacteria may benefit the plant host by providing up to 20-30% of Sphagnum carbon and nitrogen, respectively. Next-generation sequencing approaches have enabled the detailed characterization of microbiome community composition in peat mosses. However, as with other ecologically or economically important plants, our knowledge of Sphagnum-microbiome associations is in its infancy. In order to attain a predictive understanding of the role of the microbiome in Sphagnum productivity and ecosystem function, the mechanisms of plant-microbiome interactions and the metabolic potential of constituent microbial populations must be revealed. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  5. Studies on sphagnum peat. III. A quantitative study on the carbohydrate constituents of sphagnum mosses and sphagnum peat

    Energy Technology Data Exchange (ETDEWEB)

    Theander, O

    1954-01-01

    A qualitative and a quantitative investigation of the carbohydrates in two sphagnum mosses and five samples of sphagnum peat of different age and degree of huminosity has been performed. The two mosses investigated showed no significant differences. Samples of very different age but with the same degree of physical huminosity were very similar, indicating that the chief changes occur at the top of the bog and/or are determined by the conditions at the start of the humification. The total amount of carbohydrates was about 90% of the organic material in the mosses and about 65% and 35% in peats with a degree of huminosity of 3-4 and 6-7 respectively. Of the constituent sugars, fructose which occurred in the mosses, was completely absent in the peat. Another sugar, which occurs in nature as a furanoside, arabinose, disappeared almost completely during the humification. The uronic acids and galactose decreased faster, while ylose and glucose decreased at about the same rate as the total carbohydrates. Mannose and probably also rhamnose are the most stable components and accumulate during the humification. The polysaccharides in mosses and peat seem to constitute a very complex mixture. The presence of a fructan in the living moss, of a polyuronide (pectin) and a large amount of more complex polysaccharides built up of galactose, xylose, rhamnose and uronic acids is indicated. The glucose, the most important constituent, probably occurs chiefly as cellulose, the presence of which has been demonstrated by other workers. Finally the behaviour of mannose during the humification indicates the presence of a stable mannan. There is no evidence of polysaccharides formed by microorganisms in the peat.

  6. Vortex rings from Sphagnum moss capsules

    Science.gov (United States)

    Whitaker, Dwight; Strassman, Sam; Cha, Jung; Chang, Emily; Guo, Xinyi; Edwards, Joan

    2010-11-01

    The capsules of Sphagnum moss use vortex rings to disperse spores to suitable habitats many kilometers away. Vortex rings are created by the sudden release of pressurized air when the capsule ruptures, and are an efficient way to carry the small spores with low terminal velocities to heights where they can be carried by turbulent wind currents. We will present our computational model of these explosions, which are carried out using a 2-D large eddy simulation (LES) on FLUENT. Our simulations can reproduce the observed motion of the spore clouds observed from moss capsules with high-speed videos, and we will discuss the roles of bursting pressure, cap mass, and capsule morphology on the formation and quality of vortex rings created by this plant.

  7. In vitro decomposition of Sphagnum by some microfungi resembles white rot of wood.

    Science.gov (United States)

    Rice, Adrianne V; Tsuneda, Akihiko; Currah, Randolph S

    2006-06-01

    The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs.

  8. High nitrogen availability reduces polyphenol content in Sphagnum peat.

    Science.gov (United States)

    Bragazza, Luca; Freeman, Chris

    2007-05-15

    Peat mosses of the genus Sphagnum constitute the bulk of living and dead biomass in bogs. These plants contain peculiar polyphenols which hamper litter peat decomposition through their inhibitory activity on microbial breakdown. In the light of the increasing availability of biologically active nitrogen in natural ecosystems, litter derived from Sphagnum mosses is an ideal substrate to test the potential effects of increased atmospheric nitrogen deposition on polyphenol content in litter peat. To this aim, we measured total nitrogen and soluble polyphenol concentration in Sphagnum litter peat collected in 11 European bogs under a chronic gradient of atmospheric nitrogen deposition. Our results demonstrate that increasing nitrogen concentration in Sphagnum litter, as a consequence of increased exogenous nitrogen availability, is accompanied by a decreasing concentration of polyphenols. This inverse relationship is consistent with reports that in Sphagnum mosses, polyphenol and protein biosynthesis compete for the same precursor. Our observation of modified Sphagnum litter chemistry under chronic nitrogen eutrophication has implications in the context of the global carbon balance, because a lower content of decay-inhibiting polyphenols would accelerate litter peat decomposition.

  9. Desiccation tolerance of Sphagnum revisited: a puzzle resolved.

    Science.gov (United States)

    Hájek, T; Vicherová, E

    2014-07-01

    As ecosystem engineers, Sphagnum mosses control their surroundings through water retention, acidification and peat accumulation. Because water retention avoids desiccation, sphagna are generally intolerant to drought; however, the literature on Sphagnum desiccation tolerance (DT) provides puzzling results, indicating the inducible nature of their DT. To test this, various Sphagnum species and other mesic bryophytes were hardened to drought by (i) slow drying; (ii) ABA application and (iii) chilling or frost. DT tolerance was assessed as recovery of chlorophyll fluorescence parameters after severe desiccation. We monitored the seasonal course of DT in bog bryophytes. Under laboratory conditions, following initial de-hardening, untreated Sphagnum shoots lacked DT; however, DT was induced by all hardening treatments except chilling, notably by slow drying, and in Sphagnum species of the section Cuspidata. In the field, sphagna in hollows and lawns developed DT several times during the growing season, responding to reduced precipitation and a lowered water table. Hummock and aquatic species developed DT only in late autumn, probably as a response to frost. Sphagnum protonemata failed to develop DT; hence, desiccation may limit Sphagnum establishment in drier habitats with suitable substrate chemistry. Desiccation avoiders among sphagna form compact hummocks or live submerged; thus, they do not develop DT in the field, lacking the initial desiccation experience, which is frequent in hollow and lawn habitats. We confirmed the morpho-physiological trade-off: in contrast to typical hollow sphagna, hummock species invest more resources in water retention (desiccation avoidance), while they have a lower ability to develop physiological DT. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  10. Brioflora del parque natural de la Albufera de Valencia

    OpenAIRE

    Gimeno, C.; Puche, Fernando

    1995-01-01

    [ES] Se ha confeccionado el catálogo de los táxones recolectados dentro de los límites del Parque Natural de la Albufera de Valencia, así como los citados en la bibliografía. Incluye un total de cuarenta y ocho briófitos de los cuales treinta y siete son musgos y once hepáticas. [EN] In this work a list of bryophytes from Albufera de Valencia Natural Park (SE Spain) is given, with 48 taxa, 37 mosses and 11 liverworts.

  11. Sphagnum moss as a growing media constituent: some effects of harvesting, processing and storage

    OpenAIRE

    S. Kumar

    2017-01-01

    The Sphagnum material used in horticulture so far has been harvested manually, and most of the available data about Sphagnum properties have been obtained from this material. A question that remains unanswered is how changes during harvesting and processing, as well as the use of mechanical methods, affect the important properties of Sphagnum moss as a growing media constituent. Some of the effects have been evaluated in Sphagnum farming projects in Germany during the past ten years, and are ...

  12. The importance of groundwater-derived carbon dioxide in the restoration of small Sphagnum bogs

    NARCIS (Netherlands)

    Patberg, Wouter; Baaijens, Gert Jan; Smolders, Alfons J. P.; Grootjans, Ab P.; Elzenga, J. Theo M.

    Essential for successful bog restoration is the reestablishment of Sphagnum mosses. High carbon dioxide availability has been shown to be of great importance for the growth of Sphagnum mosses. In well-developed Sphagnum bogs large amounts of carbon dioxide are produced by (an)aerobic decomposition

  13. Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

    Science.gov (United States)

    Walker, Anthony P.; Carter, Kelsey R.; Gu, Lianhong; Hanson, Paul J.; Malhotra, Avni; Norby, Richard J.; Sebestyen, Stephen D.; Wullschleger, Stan D.; Weston, David J.

    2017-05-01

    Sphagnum mosses are the keystone species of peatland ecosystems. With rapid rates of climate change occurring in high latitudes, vast reservoirs of carbon accumulated over millennia in peatland ecosystems are potentially vulnerable to rising temperature and changing precipitation. We investigate the seasonal drivers of Sphagnum gross primary production (GPP)—the entry point of carbon into wetland ecosystems. Continuous flux measurements and flux partitioning show a seasonal cycle of Sphagnum GPP that peaked in the late summer, well after the peak in photosynthetically active radiation. Wavelet analysis showed that water table height was the key driver of weekly variation in Sphagnum GPP in the early summer and that temperature was the primary driver of GPP in the late summer and autumn. Flux partitioning and a process-based model of Sphagnum photosynthesis demonstrated the likelihood of seasonally dynamic maximum rates of photosynthesis and a logistic relationship between the water table and photosynthesizing tissue area when the water table was at the Sphagnum surface. The model also suggested that variability in internal resistance to CO2 transport, a function of Sphagnum water content, had minimal effect on GPP. To accurately model Sphagnum GPP, we recommend the following: (1) understanding seasonal photosynthetic trait variation and its triggers in Sphagnum; (2) characterizing the interaction of Sphagnum photosynthesizing tissue area with water table height; (3) modeling Sphagnum as a "soil" layer for consistent simulation of water dynamics; and (4) measurement of Sphagnum "canopy" properties: extinction coefficient (k), clumping (Ω), and maximum stem area index (SAI).

  14. Evolution of niche preference in Sphagnum peat mosses.

    Science.gov (United States)

    Johnson, Matthew G; Granath, Gustaf; Tahvanainen, Teemu; Pouliot, Remy; Stenøien, Hans K; Rochefort, Line; Rydin, Håkan; Shaw, A Jonathan

    2015-01-01

    Peat mosses (Sphagnum) are ecosystem engineers-species in boreal peatlands simultaneously create and inhabit narrow habitat preferences along two microhabitat gradients: an ionic gradient and a hydrological hummock-hollow gradient. In this article, we demonstrate the connections between microhabitat preference and phylogeny in Sphagnum. Using a dataset of 39 species of Sphagnum, with an 18-locus DNA alignment and an ecological dataset encompassing three large published studies, we tested for phylogenetic signal and within-genus changes in evolutionary rate of eight niche descriptors and two multivariate niche gradients. We find little to no evidence for phylogenetic signal in most component descriptors of the ionic gradient, but interspecific variation along the hummock-hollow gradient shows considerable phylogenetic signal. We find support for a change in the rate of niche evolution within the genus-the hummock-forming subgenus Acutifolia has evolved along the multivariate hummock-hollow gradient faster than the hollow-inhabiting subgenus Cuspidata. Because peat mosses themselves create some of the ecological gradients constituting their own habitats, the classic microtopography of Sphagnum-dominated peatlands is maintained by evolutionary constraints and the biological properties of related Sphagnum species. The patterns of phylogenetic signal observed here will instruct future study on the role of functional traits in peatland growth and reconstruction. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  15. Detection, isolation, and characterization of acidophilic methanotrophs from Sphagnum mosses.

    Science.gov (United States)

    Kip, Nardy; Ouyang, Wenjing; van Winden, Julia; Raghoebarsing, Ashna; van Niftrik, Laura; Pol, Arjan; Pan, Yao; Bodrossy, Levente; van Donselaar, Elly G; Reichart, Gert-Jan; Jetten, Mike S M; Damsté, Jaap S Sinninghe; Op den Camp, Huub J M

    2011-08-15

    Sphagnum peatlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions. Yet little is known about the diversity and identity of the methanotrophs present in and on Sphagnum mosses of peatlands, and only a few isolates are known. The methanotrophic community in Sphagnum mosses, originating from a Dutch peat bog, was investigated using a pmoA microarray. A high biodiversity of both gamma- and alphaproteobacterial methanotrophs was found. With Sphagnum mosses as the inoculum, alpha- and gammaproteobacterial acidophilic methanotrophs were isolated using established and newly designed media. The 16S rRNA, pmoA, pxmA, and mmoX gene sequences showed that the alphaproteobacterial isolates belonged to the Methylocystis and Methylosinus genera. The Methylosinus species isolated are the first acid-tolerant members of this genus. Of the acidophilic gammaproteobacterial strains isolated, strain M5 was affiliated with the Methylomonas genus, and the other strain, M200, may represent a novel genus, most closely related to the genera Methylosoma and Methylovulum. So far, no acidophilic or acid-tolerant methanotrophs in the Gammaproteobacteria class are known. All strains showed the typical features of either type I or II methanotrophs and are, to the best of our knowledge, the first isolated (acidophilic or acid-tolerant) methanotrophs from Sphagnum mosses.

  16. Contrasting phylogeographic patterns in Sphagnum fimbriatum and Sphagnum squarrosum (Bryophyta, Sphagnopsida) in Europe.

    Science.gov (United States)

    Szövényi, Péter; Hock, Zsófia; Urmi, Edwin; Schneller, Jakob J

    2006-01-01

    The chloroplast phylogeography of two peat mosses (Sphagnum fimbriatum and Sphagnum squarrosum) with similar distributions but different life history characteristics was investigated in Europe. Our main aim was to test whether similar distributions reflect similar phylogeographic and phylodemographic processes. Accessions covering the European distributions of the species were collected and approx. 2000 bp of the chloroplast genome of each species was sequenced. Maximum parsimony, statistical parsimony and phylodemographic analyses were used to address the question of whether these species with similar distributions show evidence of similar phylogeographic and phylodemographic processes. The chloroplast haplotypes of the currently spreading species S. fimbriatum showed strong geographic structure, whereas those of S. squarrosum, which has stable historical population sizes, showed only very weak geographic affinity and were widely distributed. We hypothesize that S. fimbriatum survived the last glaciations along the Atlantic coast of Europe, whereas S. squarrosum had numerous, scattered refugia in Europe. The dominance of one haplotype of S. fimbriatum across almost all of Europe suggests rapid colonization after the last glacial maximum. We hypothesize that high colonizing ability is an inherent characteristic of the species and its recent expansion in Europe is a response to climate change.

  17. Antibacterial activity of sphagnum acid and other phenolic compounds found in Sphagnum papillosum against food-borne bacteria.

    Science.gov (United States)

    Mellegård, H; Stalheim, T; Hormazabal, V; Granum, P E; Hardy, S P

    2009-07-01

    To identify the phenolic compounds in the leaves of Sphagnum papillosum and examine their antibacterial activity at pH appropriate for the undissociated forms. Bacterial counts of overnight cultures showed that whilst growth of Staphylococcus aureus 50084 was impaired in the presence of milled leaves, the phenol-free fraction of holocellulose of S. papillosum had no bacteriostatic effect. Liquid chromatography-mass spectrometry analysis of an acetone-methanol extract of the leaves detected eight phenolic compounds. Antibacterial activity of the four dominating phenols specific to Sphagnum leaves, when assessed in vitro as minimal inhibitory concentrations (MICs), were generally >2.5 mg ml(-1). MIC values of the Sphagnum-specific compound 'sphagnum acid' [p-hydroxy-beta-(carboxymethyl)-cinnamic acid] were >5 mg ml(-1). No synergistic or antagonistic effects of the four dominating phenols were detected in plate assays. Sphagnum-derived phenolics exhibit antibacterial activity in vitro only at concentrations far in excess of those found in the leaves. We have both identified the phenolic compounds in S. papillosum and assessed their antibacterial activity. Our data indicate that phenolic compounds in isolation are not potent antibacterial agents and we question their potency against food-borne pathogens.

  18. Swift recovery of Sphagnum nutrient concentrations after excess supply.

    Science.gov (United States)

    Limpens, Juul; Heijmans, Monique M P D

    2008-08-01

    Although numerous studies have addressed the effects of increased N deposition on nutrient-poor environments such as raised bogs, few studies have dealt with to what extent, and on what time-scale, reductions in atmospheric N supply would lead to recovery of the ecosystems in question. Since a considerable part of the negative effects of elevated N deposition on raised bogs can be related to an imbalance in tissue nutrient concentrations of the dominant peat-former Sphagnum, changes in Sphagnum nutrient concentration after excess N supply may be used as an early indicator of ecosystem response. This study focuses on the N and P concentrations of Sphagnum magellanicum and Sphagnum fallax before, during and after a factorial fertilization experiment with N and P in two small peatlands subject to a background bulk deposition of 2 g N m(-2) year(-1). Three years of adding N (4.0 g N m(-2) year(-1)) increased the N concentration, and adding P (0.3 g P m(-2) year(-1)) increased the P concentration in Sphagnum relative to the control treatment at both sites. Fifteen months after the nutrient additions had ceased, N concentrations were similar to the control whereas P concentrations, although strongly reduced, were still slightly elevated. The changes in the N and P concentrations were accompanied by changes in the distribution of nutrients over the capitulum and the stem and were congruent with changes in translocation. Adding N reduced the stem P concentration, whereas adding P reduced the stem N concentration in favor of the capitulum. Sphagnum nutrient concentrations quickly respond to reductions in excess nutrient supply, indicating that a management policy aimed at reducing atmospheric nutrient input to bogs can yield results within a few years.

  19. Experiments on the effect of sphagnum on the pH of salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K T; Thompson, T G

    1936-01-01

    Addition of sphagnum to salt solutions produced marked increases in the concentrations of the hydrogen ions, as measured both electrometrically and colorimetrically. The greater the concentration of the salt solution, the greater the increase in hydrogen ion concentration upon the addition of sphagnum. With a given salt concentration, the hydrogen ion concentration increased with increase in quantity of sphagnum added. The divalent cations produced greater increases in the hydrogen concentration than the monovalent cations for equal weights of sphagnum. Divalent anions, while showing an increase in hydrogen ions, upon the addition of sphagnum were far less effective in increasing the hydrogen ion concentrations. Sphagnum may be a useful reagent for regulating the acidity of salt solutions for many types of scientific work. It seems probable that the adsorption of metallic and hydroxyl ions explains, at least in part, the acidity of the water of sphagnum bogs.

  20. The role of Sphagnum mosses in the methane cycling of a boreal mire.

    Science.gov (United States)

    Larmola, Tuula; Tuittila, Eeva-Stiina; Tiirola, Marja; Nykänen, Hannu; Martikainen, Pertti J; Yrjälä, Kim; Tuomivirta, Tero; Fritze, Hannu

    2010-08-01

    Peatlands are a major natural source of atmospheric methane (CH4). Emissions from Sphagnum-dominated mires are lower than those measured from other mire types. This observation may partly be due to methanotrophic (i.e., methane-consuming) bacteria associated with Sphagnum. Twenty-three of the 41 Sphagnum species in Finland can be found in the peatland at Lakkasuo. To better understand the Sphagnum-methanotroph system, we tested the following hypotheses: (1) all these Sphagnum species support methanotrophic bacteria; (2) water level is the key environmental determinant for differences in methanotrophy across habitats; (3) under dry conditions, Sphagnum species will not host methanotrophic bacteria; and (4) methanotrophs can move from one Sphagnum shoot to another in an aquatic environment. To address hypotheses 1 and 2, we measured the water table and CH4 oxidation for all Sphagnum species at Lakkasuo in 1-5 replicates for each species. Using this systematic approach, we included Sphagnum spp. with narrow and broad ecological tolerances. To estimate the potential contribution of CH4 to moss carbon, we measured the uptake of delta13C supplied as CH4 or as carbon dioxide dissolved in water. To test hypotheses 2-4, we transplanted inactive moss patches to active sites and measured their methanotroph communities before and after transplantation. All 23 Sphagnum species showed methanotrophic activity, confirming hypothesis 1. We found that water level was the key environmental factor regulating methanotrophy in Sphagnum (hypothesis 2). Mosses that previously exhibited no CH4 oxidation became active when transplanted to an environment in which the microbes in the control mosses were actively oxidizing CH4 (hypothesis 4). Newly active transplants possessed a Methylocystis signature also found in the control Sphagnum spp. Inactive transplants also supported a Methylocystis signature in common with active transplants and control mosses, which rejects hypothesis 3. Our

  1. Peatmoss (Sphagnum) diversification associated with Miocene Northern Hemisphere climatic cooling?

    Science.gov (United States)

    Shaw, A Jonathan; Devos, Nicolas; Cox, Cymon J; Boles, Sandra B; Shaw, Blanka; Buchanan, Alex M; Cave, Lynette; Seppelt, Rodney

    2010-06-01

    Global climate changes sometimes spark biological radiations that can feed back to effect significant ecological impacts. Northern Hemisphere peatlands dominated by living and dead peatmosses (Sphagnum) harbor almost 30% of the global soil carbon pool and have functioned as a net carbon sink throughout the Holocene, and probably since the late Tertiary. Before that time, northern latitudes were dominated by tropical and temperate plant groups and ecosystems. Phylogenetic analyses of mosses (phylum Bryophyta) based on nucleotide sequences from the plastid, mitochondrial, and nuclear genomes indicate that most species of Sphagnum are of recent origin (ca. Sphagnum species are not only well-adapted to boreal peatlands, they create the conditions that promote development of peatlands. The recent radiation that gave rise to extant diversity of peatmosses is temporally associated with Miocene climatic cooling in the Northern Hemisphere. The evolution of Sphagnum has had profound influences on global biogeochemistry because of the unique biochemical, physiological, and morphological features of these plants, both while alive and after death. 2010 Elsevier Inc. All rights reserved.

  2. Sphagnum distribution patterns along environmental gradients in Bulgaria

    Czech Academy of Sciences Publication Activity Database

    Hájková, Petra; Hájek, Michal

    2007-01-01

    Roč. 29, č. 1 (2007), s. 18-26 ISSN 0373-6687 Grant - others:GA AV ČR(CZ) KJB6163302 Institutional research plan: CEZ:AV0Z60050516 Keywords : Sphagnum * the Balkans * ecology Subject RIV: EF - Botanics Impact factor: 1.218, year: 2007

  3. The disappearance of Sphagnum imbricatum from Butterburn Flow, UK

    NARCIS (Netherlands)

    McClymont, E.L.; Mauquoy, D.; Yeloff, D.; Broekens, P.; van Geel, B.; Charman, D.J.; Pancost, R.D.; Chambers, F.M.; Evershed, R.P.

    2008-01-01

    The disappearance of the previously abundant moss species Sphagnum imbricatum has been investigated at Butterburn Flow, northern England, using organic geochemical, elemental, macrofossil, pollen and testate amoebae analyses. Variations in the assemblage of peat-forming plants were tracked using the

  4. Revival of Dutch Sphagnum bogs: a reasonable perspective?

    NARCIS (Netherlands)

    Tomassen, H.B.M.

    2004-01-01

    In the Netherlands, the area of raised bogs has been virtually lost during two millennia of human impact. Much effort has been invested in rewetting these cut-over bogs, but the recovery of Sphagnum-dominated vegetation often failed. The work presented includes research on the role of hydrochemistry

  5. The Sphagnum microbiome supports bog ecosystem functioning under extreme conditions.

    Science.gov (United States)

    Bragina, Anastasia; Oberauner-Wappis, Lisa; Zachow, Christin; Halwachs, Bettina; Thallinger, Gerhard G; Müller, Henry; Berg, Gabriele

    2014-09-01

    Sphagnum-dominated bogs represent a unique yet widely distributed type of terrestrial ecosystem and strongly contribute to global biosphere functioning. Sphagnum is colonized by highly diverse microbial communities, but less is known about their function. We identified a high functional diversity within the Sphagnum microbiome applying an Illumina-based metagenomic approach followed by de novo assembly and MG-RAST annotation. An interenvironmental comparison revealed that the Sphagnum microbiome harbours specific genetic features that distinguish it significantly from microbiomes of higher plants and peat soils. The differential traits especially support ecosystem functioning by a symbiotic lifestyle under poikilohydric and ombrotrophic conditions. To realise a plasticity-stability balance, we found abundant subsystems responsible to cope with oxidative and drought stresses, to exchange (mobile) genetic elements, and genes that encode for resistance to detrimental environmental factors, repair and self-controlling mechanisms. Multiple microbe-microbe and plant-microbe interactions were also found to play a crucial role as indicated by diverse genes necessary for biofilm formation, interaction via quorum sensing and nutrient exchange. A high proportion of genes involved in nitrogen cycle and recycling of organic material supported the role of bacteria for nutrient supply. 16S rDNA analysis indicated a higher structural diversity than that which had been previously detected using PCR-dependent techniques. Altogether, the diverse Sphagnum microbiome has the ability to support the life of the host plant and the entire ecosystem under changing environmental conditions. Beyond this, the moss microbiome presents a promising bio-resource for environmental biotechnology - with respect to novel enzymes or stress-protecting bacteria. © 2014 John Wiley & Sons Ltd.

  6. Effects of elevated atmospheric CO2 concentration and increased nitrogen deposition on growth and chemical composition of ombrotrophic Sphagnum balticum and oligo-mesotrophic Sphagnum papillosum

    NARCIS (Netherlands)

    Van der Heijden, E; Jauhiainen, J; Silvola, J; Vasander, H; Kuiper, PJC

    2000-01-01

    The ombrotrophic Sphagnum balticum (Russ.) C. Jens. and the oligo-mesotrophic Sphagnum papillosum Lindb. were grown at ambient (360 mu l l(-1)) and at elevated (720 mu l l(-1)) atmospheric CO2 concentrations and at different nitrogen deposition rates, varying between 0 and 30kg N ha(-1) yr(-1), The

  7. Preferential degradation of polyphenols from Sphagnum – 4-Isopropenylphenol as a proxy for past hydrological conditions in Sphagnum-dominated peat

    NARCIS (Netherlands)

    Schellekens, J.; Bindler, R.; Martinez Cortizas, A.; McClymont, E.L.; Abbott, G.D.; Biester, H.; Pontevedra Pombal, X.; Buurman, P.

    2015-01-01

    The net accumulation of remains of Sphagnum spp. is fundamental to the development of many peatlands. The effect of polyphenols from Sphagnum on decomposition processes is frequently cited but has barely been studied. The central area of the Rödmossamyran peatland (Sweden) is an open lawn that

  8. Sphagnum moss as a growing media constituent: some effects of harvesting, processing and storage

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2017-09-01

    Full Text Available The Sphagnum material used in horticulture so far has been harvested manually, and most of the available data about Sphagnum properties have been obtained from this material. A question that remains unanswered is how changes during harvesting and processing, as well as the use of mechanical methods, affect the important properties of Sphagnum moss as a growing media constituent. Some of the effects have been evaluated in Sphagnum farming projects in Germany during the past ten years, and are described in this article. Different possibilities for drying, screening and cleaning the Sphagnum material are described. The results obtained indicate that Sphagnum moss can be dried and processed using mechanical methods without negative impacts on its quality as a growing media constituent.

  9. Sphagnum growth in floating cultures: Effect of planting design

    Directory of Open Access Journals (Sweden)

    Y. Hoshi

    2017-11-01

    Full Text Available To establish rapid and stable Sphagnum growth, capitulum culture of a selected strain of S. palustre was carried out using a floating culture method. Four planting treatments were tested at mountain and urban sites in Kumamoto Prefecture on Kyushu Island, south-west Japan. Capitula were planted in colonies of different sizes on 30 cm square floating rafts, but with strict control of the number (75–77 of capitula per raft. The initial cover of live green Sphagnum ranged from 15 to 20 %. Growth of the colonies was followed throughout the growing season (April to November of 2008. After three months, green coverage rates reached 40–50 % in all planting treatments. At the end of the growing season, the highest Sphagnum cover (almost 90 % at the urban site was recorded in the planting treatment with eleven re-introduced colonies of seven capitula (‘11×7cap’, while the highest capitulum number and biomass (dry weight gain occurred in the ‘4×19cap’ planting treatment. Average stem elongation ranged from 5 cm to 7 cm in the ‘77×1cap’ and ‘4×19cap’planting treatments, respectively, indicating that the larger sized colony grew longer stems. However, contrary to expectation, the ‘4×19cap’planting treatment - which had the largest colony size - did not deliver the highest number of newly formed side shoots.

  10. Cell-wall polysaccharides play an important role in decay resistance of Sphagnum and actively depressed decomposition in vitro

    NARCIS (Netherlands)

    Hajek, T.; Ballance, S.; Limpens, J.; Verhoeven, J.T.A.; Zijlstra, M.J.

    2011-01-01

    Sphagnum-dominated peatlands head the list of ecosystems with the largest known reservoirs of organic carbon (C). The bulk of this C is stored in decomposition-resistant litter of one bryophyte genus: Sphagnum. Understanding how Sphagnum litter chemistry controls C mineralization is essential for

  11. The effect of temperature on growth and competition between Sphagnum species

    NARCIS (Netherlands)

    Breeuwer, A.J.G.; Heijmans, M.M.P.D.; Robroek, B.J.M.; Berendse, F.

    2008-01-01

    Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four

  12. Photosynthetic performance in Sphagnum transplanted along a latitudinal nitrogen deposition gradient

    NARCIS (Netherlands)

    Granath, G.; Strengbom, J.; Breeuwer, A.J.G.; Heijmans, M.M.P.D.; Berendse, F.; Rydin, H.

    2009-01-01

    Increased N deposition in Europe has affected mire ecosystems. However, knowledge on the physiological responses is poor. We measured photosynthetic responses to increasing N deposition in two peatmoss species (Sphagnum balticum and Sphagnum fuscum) from a 3-year, north-south transplant experiment

  13. Sphagnum re-introduction in degraded peatlands: the effects of aggregation, species and water table

    NARCIS (Netherlands)

    Robroek, B.J.M.; Ruijven, van J.; Schouten, M.G.C.; Breeuwer, A.J.G.; Crushell, P.H.; Berendse, F.; Limpens, J.

    2009-01-01

    In European peatlands which have been drained and cut-over in the past, re-vegetation often stagnates after the return of a species-poor Sphagnum community. Re-introduction of currently absent species may be a useful tool to restore a typical, and more diverse, Sphagnum vegetation and may ultimately

  14. Sphagnum mosses limit total carbon consumption during fire in Alaskan black spruce forests

    Science.gov (United States)

    G. Shetler; .R. Turetsky; E. Kane; E. Kasischke

    2008-01-01

    The high water retention of hummock-forming Sphagnum species minimizes soil moisture fluctuations and might protect forest floor organic matter from burning during wildfire. We hypothesized that Sphagnum cover reduces overall forest floor organic matter consumption during wildfire compared with other ground-layer vegetation. We...

  15. Greenhouse gas balance of an establishing Sphagnum culture on a former bog grassland in Germany

    Directory of Open Access Journals (Sweden)

    A. Günther

    2017-04-01

    Full Text Available The cultivation of Sphagnum mosses on re-wetted peat bogs for use in horticulture is a new land use strategy. We provide the first greenhouse gas balances for a field-scale Sphagnum farming experiment on former bog grassland, in its establishment phase. Over two years we used closed chambers to make measurements of GHG exchange on production strips of Sphagnum palustre L. and Sphagnum papillosum Lindb. and on irrigation ditches. Methane fluxes of both Sphagnum species showed a significant decrease over the study period. This trend was stronger for S. papillosum. In contrast, the estimated CO2 fluxes did not show a significant temporal trend over the study period. The production strips of both Sphagnum species were net GHG sinks of 5–9 t ha 1 a 1 (in CO2-equivalents during the establishment phase of the moss carpets. In comparison, the ditches were a CO2 source instead of a CO2 sink and emitted larger amounts of CH4, resulting in net GHG release of ~11 t ha 1 a 1 CO2-equivalents. We conclude that Sphagnum farming fields should be designed to minimise the area covered by irrigation ditches. Overall, Sphagnum farming on bogs has lower on-field GHG emissions than low-intensity agriculture.

  16. Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

    Science.gov (United States)

    Anthony P. Walker; Kelsey R. Carter; Lianhong Gu; Paul J. Hanson; Avni Malhotra; Richard J. Norby; Stephen D. Sebestyen; Stan D. Wullschleger; David J. Weston

    2017-01-01

    Sphagnum mosses are the keystone species of peatland ecosystems. With rapid rates of climate change occurring in high latitudes, vast reservoirs of carbon accumulated over millennia in peatland ecosystems are potentially vulnerable to rising temperature and changing precipitation. We investigate the seasonal drivers of Sphagnum...

  17. Mixing ratio and species affect the use of substrate-derived CO2 by Sphagnum

    NARCIS (Netherlands)

    Limpens, J.; Robroek, B.J.M.; Heijmans, M.M.P.D.; Tomassen, H.B.M.

    2008-01-01

    Question: Can mixing ratio and species affect the use of substrate-derived CO2 by Sphagnum? Location: Poor fen in south Sweden and greenhouse in Wageningen, The Netherlands. Methods: Two mixing ratios of Sphagnum cuspidatum and S. magellanicum were exposed to two levels of CO2 by pumping CO2

  18. Peatland restoration in Canada by the sphagnum moss layer transfer method

    Energy Technology Data Exchange (ETDEWEB)

    Rochefort, L.; Boismenu, C. [Laval Univ., Quebec City, PQ (Canada). Dept. de Phytologie, Peatland Ecology and Research Group; Quinty, F. [SNC-Lavalin, Montreal, PQ (Canada)

    2009-04-01

    This article described a peatland restoration approach that has received international recognition for restoring the ecological functions of cutover sphagnum dominated peatlands. The Peatland Ecology Research Group (PERG) conducted a long-term study at the Bois-des-Bel (BDB) peatland site in Quebec to restore plant composition to a peat accumulating ecosystem. The sphagnum moss layer transfer restoration method includes 5 obligatory steps and one optional. These include planning; surface preparation; plant collection and spreading; straw mulch spreading; blocking drainage ditches; and fertilization if needed. Variable moisture conditions throughout the restoration site contribute to the spatial variability in the development of the sphagnum layer. The site has been monitored each year since its restoration. sphagnum cover reached 60 per cent in the restored zone in 2005, a value close to the range of sphagnum cover found in natural sites. In addition, a new moss layer has developed with an average of 25 cm in thickness. 27 refs., 4 figs.

  19. Effects of bryophytes on succession from alkaline marsh to Sphagnum bog

    Energy Technology Data Exchange (ETDEWEB)

    Glime, J.M.; Wetzel, R.G.; Kennedy, B.J.

    1982-10-01

    The alkaline eastern marsh of Lawrence Lake, a marl lake in southwestern Michigan, was sampled by randomly placed line transects to determine the bryophyte cover and corresponding vascular plant zones. Cluster analysis indicated three distinct bryophyte zones which correspond with the recognized vascular plant zones. Mosses occupied over 50% of the surface in some areas. Invasion of Sphagnum, vertical zonation of the mosses on hummocks, zonation with distance from the lake, the abundance of non-Sphagnum moss hummocks, and the ability of the non-Sphagnum species to lower the pH of marsh water during laboratory incubations are evidence that non-Sphagnum mosses facilitate succession from alkaline marsh to Sphagnum bog.

  20. Investigations of the structure and function of bacterial communities associated with Sphagnum mosses.

    Science.gov (United States)

    Opelt, Katja; Chobot, Vladimir; Hadacek, Franz; Schönmann, Susan; Eberl, Leo; Berg, Gabriele

    2007-11-01

    High acidity, low temperature and extremely low concentration of nutrients form Sphagnum bogs into extreme habitats for organisms. Little is known about the bacteria associated with living Sphagnum plantlets, especially about their function for the host. Therefore, we analysed the endo- and ectophytic bacterial populations associated with two widely distributed Sphagnum species, Sphagnum magellanicum and Sphagnum fallax, by a multiphasic approach. The screening of 1222 isolates for antagonistic activity resulted in 326 active isolates. The bacterial communities harboured a high proportion of antifungal (26%) but a low proportion of antibacterial isolates (0.4%). Members of the genus Burkholderia (38%) were found to be the most dominant group of antagonistic bacteria. The finding that a large proportion (89%) of the antagonistic bacteria produced antifungal compounds may provide an explanation for the well-known antimicrobial activity of certain Sphagnum species. The secondary metabolites of the Sphagnum species themselves were analysed by HPLC-PDA. The different spectra of detected compounds may not only explain the antifungal activity but also the species specificity of the microbial communities. The latter was analysed using cultivation-independent single-stranded conformation polymorphism (SSCP) analysis. Using Burkholderia-specific primers we found a high diversity of Burkholderia isolates in the endophytic and ectophytic habitats of Sphagnum. Furthermore, a high diversity of nitrogen-fixing bacteria was detected by using nifH-specific primers, especially inside Sphagnum mosses. In conclusion, this study provides evidence that both Sphagnum species were colonized by characteristic bacterial populations, which appear to be important for pathogen defence and nitrogen fixation.

  1. Outstanding accumulation of Sphagnum palustre in central-southern Italy

    Science.gov (United States)

    Casella, Laura; Zaccone, Claudio

    2017-04-01

    Lake Fibreno is a site where some outstanding anomalies for the flora and vegetation of the wetlands of peninsular Italy are concentrated. Here one the southernmost European population of Sphagnum palustre occurs, and is restricted on the surface of a free-floating island, i.e., a round-shaped portion of fen (with a core of Sphagnum), erratically floating on the surface of a submerged sinkhole. Geological evidences point out the existence in the area of a large lacustrine basin since Late Pleistocene. The progressive filling of the lake, caused by changing in climatic conditions and neotectonic events, resulted in the formation of peat deposits in the area, following different depositional cycles in a swampy environment. So that, the studied free-floating island, probably originated around lake margins in the waterlogged area, was somehow isolated from the bank and started to float. Once the separation occurred, sedge peat stopped to accumulate, thus enhancing the role of S. palustre as the main peat-forming plant. The vegetation occurring at the moment of the isolation of the island was a coverage of Salix cinerea/Populus tremula stands below which cushions of moss and, in a lower extent, Thelypteris palustris/Equisetum palustre accumulated resulting in the formation of 2-3 meters of peat dominated by reeds and sedges. This vegetation has been partially degraded by grazing until 1970s, while in 1980s the lake became a nature reserve. Since then, the succession could resume in a spontaneous and natural way and it was possible for the vegetation to recover to natural dynamics and growing rate. The Sphagnum tussocks were measured in an empirical way at a distance of about 60 years after the last signaling and the result was a measurement of an accretion open to about 70 cm thick. Moreover, in a recent study, a 4-m deep peat core was collected from the centre of the island and results were surprising. In fact, 14C age dating, confirmed using 210Pb and 137Cs, showed

  2. Diversidad de musgos en ambientes degradados sujetos a restauración en el Parque Nacional Lago Puelo (Chubut, Argentina Moss diversity in degraded environments under restoring in the Lago Puelo National Park (Chubut, Argentina

    Directory of Open Access Journals (Sweden)

    ADRIANA E ROVERE

    2011-12-01

    Full Text Available La restauración ecológica es una disciplina que intenta recuperar atributos perdidos en un ecosistema (diversidad de especies, estructura y función. El objetivo de este trabajo fue evaluar la diversidad de musgos y sus formas de vida en tres ambientes con diferentes niveles de degradación y los sustratos en los que estos se desarrollan. El área de estudio corresponde a un sector que se está restaurando dentro de la Reserva Nacional Lago Puelo. En ella se encuentran tres ambientes distintos: (1 área remanente de bosque maduro de Nothofagus dombeyi, (2 bosque secundario de Austrocedrus chilensis, y (3 matorral dominado por especies exóticas. Se recorrió cada uno de los ambientes, registrando los sustratos con musgos, formas de vida y géneros. Los resultados evidencian una reducción de los sustratos disponibles y de las especies presentes conforme avanza el grado de alteración, desde el área de bosque maduro de N. dombeyi (9 sustratos: 17 géneros: 7 formas de vida, al sector de bosque secundario de A. chilensis (6 sustratos: 8 géneros: 5 formas de vida, siendo menor en el matorral dominado por especies exóticas (1 sustrato: 4 géneros: 3 formas de vida. Los musgos desempeñan funciones importantes en los ecosistemas, son fundamentales en el balance hídrico, pioneros en suelos inestables controlando la erosión y colonizando sitios alterados, sirven como hábitat y alimento para invertebrados, y también constituyen sitios propicios para la germinación de plantas vasculares. Si bien algunas especies leñosas ven afectada su germinación por la presencia de musgos, estos facilitan la germinación de otras especies arbóreas de los bosques templados. Los resultados podrían ser utilizados en restauración, ya sea recreando los sustratos ausentes o realizando traslado de sustratos con musgos, a fin de favorecer la recuperación de áreas boscosas degradadas considerando la biodiversidad original.Ecological restoration is a discipline

  3. CARACTERIZACIÓN DE LA COMUNIDAD DE MACROINVERTEBRADOS DE LA QUEBRADA PALOBLANCO DE LA CUENCA DEL RÍO OTÚN (RISARALDA, COLOMBIA)

    OpenAIRE

    ELEONORA BERNAL; DUBERNEY GARCÍA; MIGUEL A. NOVOA; ATTICUS PINZÓN

    2006-01-01

    Se realizó un estudio de las comunidades de macroinvertebrados presentes en la quebrada Paloblanco, ubicada en la cuenca del río Otún (Risaralda, Colombia). Los puntos de muestreo seleccionados corresponden a la cabecera y la zona cercana a la desembocadura en el río Otún, ambos con características geomorfológicas de corrientes de primer orden. En cada punto se colectaron los macroinvertebrados de las unidades funcionales hojarasca, epiliton, musgo y grava, junto con una muestra de deriva y f...

  4. Caracterización de la comunidad de macroinvertebrados de la Quebrada Paloblanco de la Cuenca del Río Otún (Risaralda, Colombia)

    OpenAIRE

    Eleonora Bernal Pinilla; Duberney García García; Miguel Adriano Novoa Bravo; Atticus Pinzón Rodríguez

    2006-01-01

    Se realizó un estudio de las comunidades de macroinvertebrados presentes en la quebrada Paloblanco, ubicada en la cuenca del río Otún (Risaralda, Colombia). Los puntos de muestreo seleccionados corresponden a la cabecera y la zona cercana a la desembocadura en el río Otún, ambos con características geomorfológicas de corrientes de primer orden. En cada punto se colectaron los macroinvertebrados de las unidades funcionales hojarasca, epiliton, musgo y grava, junto con una muestra de deriva y f...

  5. Characteristics of Eastern Canadian cultivated Sphagnum and potential use as a substitute for perlite and vermiculite in peat-based horticultural substrates

    OpenAIRE

    M. Aubé; M. Quenum; L.L. Ranasinghe

    2015-01-01

    Sphagnum cultivation on harvested peatlands to meet wetland restoration objectives could be an economically feasible activity since cultivated Sphagnum has potential horticultural applications. We compared the characteristics of cultivated Sphagnum from Shippagan (Canada) with those of non-cultivated Sphagnum products from Chile, New Zealand and Canada, and assessed its potential as a perlite and vermiculite substitute in horticultural peat-based substrates. Shippagan cultivated Sphagnum was ...

  6. Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands

    International Nuclear Information System (INIS)

    Granath, Gustaf; Limpens, Juul; Posch, Maximilian; Mücher, Sander; Vries, Wim de

    2014-01-01

    To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900–2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate. - Highlights: • We model the effect of N deposition combined with climate on production of Sphagnum between 1900 and 2050. • Spatially explicit projections are indicated on an updated European peatland distribution map. • Results stress the vulnerability of temperate Sphagnum peatlands to current and future N deposition. • Future impacts of N deposition on Sphagnum productivity likely depend more on climate change than on N deposition rate. - Temperate Sphagnum peatlands are vulnerable to current and future N deposition and current critical loads for peatlands are likely to hold under a future climate

  7. Sphagnum mosses harbour highly specific bacterial diversity during their whole lifecycle.

    Science.gov (United States)

    Bragina, Anastasia; Berg, Christian; Cardinale, Massimiliano; Shcherbakov, Andrey; Chebotar, Vladimir; Berg, Gabriele

    2012-04-01

    Knowledge about Sphagnum-associated microbial communities, their structure and their origin is important to understand and maintain climate-relevant Sphagnum-dominated bog ecosystems. We studied bacterial communities of two cosmopolitan Sphagnum species, which are well adapted to different abiotic parameters (Sphagnum magellanicum, which are strongly acidic and ombrotrophic, and Sphagnum fallax, which are weakly acidic and mesotrophic), in three Alpine bogs in Austria by a multifaceted approach. Great differences between bacterial fingerprints of both Sphagna were found independently from the site. This remarkable specificity was confirmed by a cloning and a deep sequencing approach. Besides the common Alphaproteobacteria, we found a discriminative spectrum of bacteria; although Gammaproteobacteria dominated S. magellanicum, S. fallax was mainly colonised by Verrucomicrobia and Planctomycetes. Using this information for fluorescent in situ hybridisation analyses, corresponding colonisation patterns for Alphaproteobacteria and Planctomycetes were detected. Bacterial colonies were found in high abundances inside the dead big hyalocytes, but they were always connected with the living chlorocytes. Using multivariate statistical analysis, the abiotic factors nutrient richness and pH were identified to modulate the composition of Sphagnum-specific bacterial communities. Interestingly, we found that the immense bacterial diversity was transferred via the sporophyte to the gametophyte, which can explain the high specificity of Sphagnum-associated bacteria over long distances. In contrast to higher plants, which acquire their bacteria mainly from the environment, mosses as the phylogenetically oldest land plants maintain their bacterial diversity within the whole lifecycle.

  8. A phylogenetic delimitation of the "Sphagnum subsecundum complex" (Sphagnaceae, Bryophyta).

    Science.gov (United States)

    Shaw, A Jonathan; Boles, Sandra; Shaw, Blanka

    2008-06-01

    A seemingly obvious but sometimes overlooked premise of any evolutionary analysis is delineating the group of taxa under study. This is especially problematic in some bryophyte groups because of morphological simplicity and convergence. This research applies information from nucleotide sequences for eight plastid and nuclear loci to delineate a group of northern hemisphere peat moss species, the so-called Sphagnum subsecundum complex, which includes species known to be gametophytically haploid or diploid (i.e., sporophytically diploid-tetraploid). Despite the fact that S. subsecundum and several species in the complex have been attributed disjunct ranges that include all major continents, phylogenetic analyses suggest that the group is actually restricted to Europe and eastern North America. Plants from western North America, from California to Alaska, which are morphologically similar to species of the S. subsecundum complex in eastern N. America and Europe, actually belong to a different deep clade within Sphagnum section Subsecunda. One species often considered part of the S. subsecundum complex, S. contortum, likely has a reticulate history involving species in the two deepest clades within section Subsecunda. Nucleotide sequences have a strong geographic structure across the section Subsecunda, but shallow tip clades suggest repeated long-distance dispersal in the section as well.

  9. Symbiosis revisited: phosphorus and acid buffering stimulate N2 fixation but not Sphagnum growth

    Science.gov (United States)

    van den Elzen, Eva; Kox, Martine A. R.; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S. M.; Ettwig, Katharina F.; Lamers, Leon P. M.

    2017-03-01

    In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands, are, however, highly variable, and experimental work on regulating factors that can mechanistically explain this variation is largely lacking. For two common fen species (Sphagnum palustre and S. squarrosum) from a high nitrogen deposition area (25 kg N ha-1 yr-1), we found that diazotrophic activity (as measured by 15 - 15N2 labeling) was still present at a rate of 40 nmol N gDW-1 h-1. This was surprising, given that nitrogen fixation is a costly process. We tested the effects of phosphorus availability and buffering capacity by bicarbonate-rich water, mimicking a field situation in fens with stronger groundwater or surface water influence, as potential regulators of nitrogen fixation rates and Sphagnum performance. We expected that the addition of phosphorus, being a limiting nutrient, would stimulate both diazotrophic activity and Sphagnum growth. We indeed found that nitrogen fixation rates were doubled. Plant performance, in contrast, did not increase. Raised bicarbonate levels also enhanced nitrogen fixation, but had a strong negative impact on Sphagnum performance. These results explain the higher nitrogen fixation rates reported for minerotrophic and more nutrient-rich peatlands. In addition, nitrogen fixation was found to strongly depend on light, with rates 10 times higher in light conditions suggesting high reliance on phototrophic organisms for carbon. The contrasting effects of phosphorus and bicarbonate on Sphagnum spp. and their diazotrophic communities reveal strong differences in the optimal niche for both partners with respect to conditions and resources. This suggests a trade-off for the symbiosis of nitrogen fixing microorganisms with their Sphagnum

  10. Effect of mechanical fragmentation of sphagnum on population density and structure of micromycete communities

    Science.gov (United States)

    Semenova, T. A.; Golovchenko, A. V.

    2017-07-01

    The population density and taxonomic structure of micromycetes were monitored for six months in a model experiment with natural and mechanically fragmented (fine and coarse) samples of sphagnum. Sphagnum fragmentation favored an increase in the number of micromycetes only during the first week of the experiment. On the average, the number of micromycetes in fine-fragmented samples was two times greater than that in the coarse-fragmented samples. The diversity of micromycetes increased in the fragmented samples of sphagnum owing to the activation of some species, which remained in the inactive state as spores in the peat before fragmentation.

  11. Reintroduction of Sphagnum into harvested peatlands: evaluation of various methods for protection against dessication

    Energy Technology Data Exchange (ETDEWEB)

    Rochefort, L.; Bastien, D.F. [Laval University, Sainte-Foy, PQ (Canada). Dept. of Phytology

    1998-09-01

    In order to restore peatlands after peat harvesting operations, Sphagnum diaspores were introduced in combination with 1) physical protection devices or 2) an irrigating system. The response of five Sphagnum species was investigated in relation to two types of peat substrates for two growing seasons. The physical protections consisting of plastic shade cloth (40% and 60% shade) improved the development of a greater number of capitula compared with control surfaces without protection or surfaces covered with a perforated polyethylene sheet. This stimulating effect could be caused by higher humidity created by a shale screen. Irrigation also enhanced the establishment success of Sphagnum but the effect was less successful than expected.

  12. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe

    Energy Technology Data Exchange (ETDEWEB)

    Jirousek, Martin, E-mail: machozrut@mail.muni.c [Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno (Czech Republic); Hajek, Michal [Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno (Czech Republic); Bragazza, Luca [WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Site Lausanne, Station 2, Case Postale 96, CH-1015 Lausanne (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), Laboratory of Ecological Systems - ECOS, Batiment GR, Station 2, CH-1015 Lausanne (Switzerland); Department of Biology and Evolution, University of Ferrara, Corso Ercole I d' Este 32, I-44100 Ferrara (Italy)

    2011-02-15

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m{sup -2} year{sup -1} in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. - Research highlights: Despite high atmopsheric nitrogen deposition, Sphagnum mosses still have rather low N:P ratio. Regional climate and landscape management can enhance P and K availability in bogs. Sphagnum species of the Cuspidata section were characterised by lower N:P ratio. - Regional climate and local forestry practices are expected to alter nutrient stoichiometry in Sphagnum mosses at high atmospheric N deposition in Central-East Europe.

  13. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe

    International Nuclear Information System (INIS)

    Jirousek, Martin; Hajek, Michal; Bragazza, Luca

    2011-01-01

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m -2 year -1 in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. - Research highlights: → Despite high atmopsheric nitrogen deposition, Sphagnum mosses still have rather low N:P ratio.→ Regional climate and landscape management can enhance P and K availability in bogs. → Sphagnum species of the Cuspidata section were characterised by lower N:P ratio. - Regional climate and local forestry practices are expected to alter nutrient stoichiometry in Sphagnum mosses at high atmospheric N deposition in Central-East Europe.

  14. Effect of repeated mowing to reduce graminoid plant cover on the moss carpet at a Sphagnum farm in North America

    Directory of Open Access Journals (Sweden)

    M. Guêné-Nanchen

    2017-09-01

    Full Text Available Sphagnum farming is defined as the sustainable production of non-decomposed Sphagnum biomass on a cyclical and renewable basis. In this article, the influence and necessity of mowing graminoid plants to optimise Sphagnum growth in Sphagnum farming basins are examined. Repeated mowing was applied to reduce graminoid plant cover at two different stages of the production cycle (one-year-old and seven-year-old Sphagnum moss carpet at the beginning of the experiment at an experimental Sphagnum farm in eastern Canada. Sphagnum growth (cover, biomass, moss layer thickness was measured after three years of mowing. In addition, a greenhouse experiment was carried out to determine whether there is a threshold for graminoid plant cover beyond which mowing becomes necessary. Sphagnum cover and biomass were not affected by repeated mowing, even if mowing reduced the cover of graminoid plants. Thus, it appears that mowing is unnecessary if the dominant vascular species is a graminoid plant such as Eriophorum angustifolium, which accumulates minimal amounts of litter. Furthermore, high cover of Eriophorum angustifolium (up to 85 % did not affect Sphagnum cover in a density-controlled greenhouse experiment. When the specific goal is Sphagnum fibre production, decisions about control of graminoid plants should be made after considering the cover, life form and litter accumulation potentials of the dominant graminoid species involved.

  15. New mosses records (Bryophyta for Goiás and Tocantins states, Brazil Ocorrências novas de musgos (Bryophyta para os Estados de Goiás e Tocantins, Brasil

    Directory of Open Access Journals (Sweden)

    Denilson Fernandes Peralta

    2008-09-01

    Full Text Available Sixty-five moss taxa are new records for Goiás and Tocantins States. Of these, 44 are new records (40 - Goiás; four - Tocantins and 23 are new sites in each of the states (19 -Goiás; four - Tocantins. Ptychostomum pallescens (Schleich. ex Schwägr. Spence and Philonotis fontana (Hedw. Brid. are new records for Brazil, and are illustrated.Após o estudo da coleção do herbário SP, foram encontradas 65 novas ocorrências de musgos para Goiás e Tocantins. Deste total, 44 táxons são primeiras referências (40 - Goiás e quatro - Tocantins e 23 táxons tiveram a distribuição geográfica ampliada em cada um dos estados (19 - Goiás e quatro - Tocantins. As espécies Ptychostomum pallescens (Schleich. ex Schwägr. Spence e Philonotis fontana (Hedw. Brid. são novas citações para o Brasil e apresentam ilustração.

  16. Seasonal pattern of metal bioaccumulation and their toxicity on Sphagnum squarrosum.

    Science.gov (United States)

    Saxena, Anuj

    2006-01-01

    Present study was undertaken as an attempt to study the effect of pollutants on biological responses of Sphagnum growing at Kainchi, Kumaon hills (Uttranchal). Sphagnum plants of almost identical size, collected from the marked sites of Kainchi in different seasons viz., monsoon, winter, summer and again in monsoon, were analysed for chlorophyll, protein, shoot length and nitrate reductase and peroxidase activities. Maximum chlorophyll, protein, shoots length and nitrate reductase activities were observed during the monsoon while minimum in summers. The abundance of Sphagnum and two other bryophytes, Marchantia and Plagiochasma was also higher in monsoon than in other seasons. The study also indicated that Sphagnum has more bioaccumulation and tolerance potential for heavy metals than Marchantia and Plagiochasma.

  17. CARACTERIZACIÓN DE LA COMUNIDAD DE MACROINVERTEBRADOS DE LA QUEBRADA PALOBLANCO DE LA CUENCA DEL RÍO OTÚN (RISARALDA, COLOMBIA) Characterization of the Macroinvertebrate Community of Paloblanco Gulch, Otun River Basin

    OpenAIRE

    ELEONORA BERNAL; DUBERNEY GARCÍA; MIGUEL A NOVOA; ATTICUS PINZÓN

    2006-01-01

    Se realizó un estudio de las comunidades de macroinvertebrados presentes en la quebrada Paloblanco, ubicada en la cuenca del río Otún (Risaralda, Colombia). Los puntos de muestreo seleccionados corresponden a la cabecera y la zona cercana a la desembocadura en el río Otún, ambos con características geomorfológicas de corrientes de primer orden. En cada punto se colectaron los macroinvertebrados de las unidades funcionales hojarasca, epiliton, musgo y grava, junto con una muestra de deriva y f...

  18. Response of Sphagnum fuscum to Nitrogen Deposition: A Case Study of Ombrogenous Peatlands in Alberta, Canada

    Science.gov (United States)

    Vitt, D.H.; Wieder, K.; Halsey, L.A.; Turetsky, M.

    2003-01-01

    Peatlands cover about 30% of northeastern Alberta and are ecosystems that are sensitive to nitrogen deposition. In polluted areas of the UK, high atmospheric N deposition (as a component of acid deposition) has been considered among the causes of Sphagnum decline in bogs (ombrogenous peatlands). In relatively unpolluted areas of western Canada and northern Sweden, short-term experimental studies have shown that Sphagnum responds quickly to nutrient loading, with uptake and retention of nitrogen and increased production. Here we examine the response of Sphagnum fuscum to enhanced nitrogen deposition generated during 34 years of oil sands mining through the determination of net primary production (NPP) and nitrogen concentrations in the upper peat column. We chose six continental bogs receiving differing atmospheric nitrogen loads (modeled using a CALPUFF 2D dispersion model). Sphagnum fuscum net primary production (NPP) at the high deposition site (Steepbank - mean of 600 g/m2; median of 486 g/m2) was over three times as high than at five other sites with lower N deposition. Additionally, production of S. fuscum may be influenced to some extent by distance of the moss surface from the water table. Across all sites, peat nitrogen concentrations are highest at the surface, decreasing in the top 3 cm with no significant change with increasing depth. We conclude that elevated N deposition at the Steepbank site has enhanced Sphagnum production. Increased N concentrations are evident only in the top 1-cm of the peat profile. Thus, 34 years after mine startup, increased N-deposition has increased net primary production of Sphagnum fuscum without causing elevated levels of nitrogen in the organic matter profile. A response to N-stress for Sphagnum fuscum is proposed at 14-34 kg ha-1 yr-1. A review of N-deposition values reveals a critical N-deposition value of between 14.8 and 15.7 kg ha -1 yr-1 for NPP of Sphagnum species.

  19. Interferences between Sphagnum and vascular plants: effects on plant community structure and peat formation

    OpenAIRE

    Malmer, Nils; Albinsson, C; Svensson, B M; Wallén, Bo

    2003-01-01

    The interference between vascular plants and peat mosses with respect to nitrogen and phosphorus was studied in a fertilization experiment and with respect to competition for light in a removal experiment in poor fens with either soligenous or topogenous hydrology using Narthecium ossifragum (L.) Huds. and three species of Sphagnum sect. Sphagnum as targets. Adding fertilizer either on the moss surface or below it confirmed the hypotheses of an asymmetric competition for nutrients, viz. that ...

  20. Factors controlling sulfur gas exchange in Sphagnum-dominated wetlands

    Science.gov (United States)

    Demello, William Zamboni; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Atmosphere-peatland exchange of reduced sulfur gases was determined seasonally in fen in NH, and in an artificially-acidified fen at the Experimental Lakes Area (ELA) in Canada. Dimethyl sulfide (DMS) dominated gas fluxes at rates as high as 400 nmol/m(sup -2)hr(sup -1). DMS fluxes measured using enclosures were much higher than those calculated using a stagnant-film model, suggesting that Sphagnum regulated efflux. Temperature controlled diel and seasonal variability in DMS emissions. Use of differing enclosure techniques indicated that vegetated peatlands consume atmospheric carbonyl sulfide. Sulfate amendments caused DMS and methane thiol concentrations in near-surface pore waters to increase rapidly, but fluxes of these gases to the atmosphere were not affected. However, emission data from sites experiencing large differences in rates of sulfate deposition from the atmosphere suggested that chronic elevated sulfate inputs enhance DMS emissions from northern wetlands.

  1. Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition.

    Science.gov (United States)

    Wiedermann, Magdalena M; Gunnarsson, Urban; Ericson, Lars; Nordin, Annika

    2009-01-01

    Here, it was investigated whether Sphagnum species have adjusted their nitrogen (N) uptake in response to the anthropogenic N deposition that has drastically altered N-limited ecosystems, including peatlands, worldwide. A lawn species, Sphagnum balticum, and a hummock species, Sphagnum fuscum, were collected from three peatlands along a gradient of N deposition (2, 8 and 12 kg N ha(-1) yr(-1)). The mosses were subjected to solutions containing a mixture of four N forms. In each solution one of these N forms was labeled with (15)N (namely (15)NH(+)(4), (15)NO(-)(3) and the amino acids [(15)N]alanine (Ala) and [(15)N]glutamic acid (Glu)). It was found that for both species most of the N taken up was from , followed by Ala, Glu, and very small amounts from NO(-)(3). At the highest N deposition site N uptake was reduced, but this did not prevent N accumulation as free amino acids in the Sphagnum tissues. The reduced N uptake may have been genetically selected for under the relatively short period with elevated N exposure from anthropogenic sources, or may have been the result of plasticity in the Sphagnum physiological response. The negligible Sphagnum NO(-)(3) uptake may make any NO(-)(3) deposited readily available to co-occurring vascular plants.

  2. Cell-wall polysaccharides play an important role in decay resistance of Sphagnum and actively depressed decomposition in vitro

    OpenAIRE

    Hajek, T.; Ballance, S.; Limpens, J.; Verhoeven, J.T.A.; Zijlstra, M.J.

    2011-01-01

    Sphagnum-dominated peatlands head the list of ecosystems with the largest known reservoirs of organic carbon (C). The bulk of this C is stored in decomposition-resistant litter of one bryophyte genus: Sphagnum. Understanding how Sphagnum litter chemistry controls C mineralization is essential for understanding potential interactions between environmental changes and C mineralization in peatlands. We aimed to separate the effects of phenolics from structural polysaccharides on decay of Sphagnu...

  3. Sphagnum restoration on degraded blanket and raised bogs in the UK using micropropagated source material: a review of progress

    Directory of Open Access Journals (Sweden)

    S.J.M Caporn

    2018-05-01

    Full Text Available There is a growing demand for a supply of Sphagnum to re-introduce to degraded peatlands. However, available supplies of Sphagnum of the desired species are often limited. We describe the propagation of Sphagnum from vegetative material in sterile tissue culture and the introduction of juvenile mosses into the field. Sphagnum produced in the laboratory in three different forms (beads, gel and plugs was introduced to different peatland surfaces on upland degraded blanket bog and lowland cut-over peatland in northern England. On degraded blanket bog, the establishment of mixed-species Sphagnum plugs was typically 99 % while the survival of beads was much lower, ranging from little above zero on bare eroding peat to a maximum of 12 % on stabilised peat surfaces. On lowland cut-over peatland, all trials took place on peat with an expanding cover of Eriophorum angustifolium and tested Sphagnum gel as well as beads and plugs. This work showed that survival and establishment of plugs was high (99 % and greater than for beads. Sphagnum gel reached a cover of 95 % in two years. The vegetative micropropagation of Sphagnum offers an effective source of Sphagnum for re-introduction to degraded peatlands.

  4. Three-genome mosses: complex double allopolyploid origins for triploid gametophytes in Sphagnum.

    Science.gov (United States)

    Karlin, Eric F; Boles, S B; Ricca, M; Temsch, E M; Greilhuber, J; Shaw, A J

    2009-04-01

    This paper documents the occurrence of allotriploidy (having three differentiated genomes) in gametophytes of two Southern Hemisphere Sphagnum species (S. australe, S. falcatulum). The pattern of microsatellite alleles indicates that both species are composed of a complex of allodiploid and allotriploid gametophytes, with the latter resulting from two allopolyploidization events. No haploid (n = x) gametophytes were found for either species. The ploidal levels suggested by the pattern of microsatellite alleles were confirmed by flow cytometry and Feulgen DNA image densitometry. For both S. australe and S. falcatulum, the respective allodiploid plants (or their ancestors) are one of the parent species of the allotriploid plants. This is the first report of triploidy in Sphagnum gametophytes occurring in nature and also the first report of the presence of three differentiated genomes in any bryophyte. It is also the first report of intersectional allopolyploidy in Sphagnum, with S. australe appearing to have parental species from Sphagnum sections Rigida and Sphagnum, and S. falcatulum having parental species from Sphagnum sections Cuspidata and Subsecunda. In both species, the allotriploid cytotypes were the most prevalent cytotype on the South Island of New Zealand. The pattern of microsatellite alleles shows the presence of two genetically distinct populations of allodiploid S. australe, possibly indicating multiple origins of polyploidy for that allodiploid cytotype. Morphological evidence is also highly indicative of recurrent polyploidy in the allotriploid cytotype of S. falcatulum. Allopolyploidy has clearly played a major evolutionary role in these two Southern Hemisphere taxa. This study, in conjunction with other recent research, indicates that allopolyploidy is a common, if not the predominant, form of polyploidy in Sphagnum.

  5. Similar diversity of Alphaproteobacteria and nitrogenase gene amplicons on two related Sphagnum mosses

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    Anastasia eBragina

    2012-01-01

    Full Text Available Sphagnum mosses represent a main component in ombrotrophic wetlands. They harbor a specific and diverse microbial community with essential functions for the host. To understand extend and degree of host specificity, Sphagnum fallax and S. angustifolium, two phylogenetically closely related species, which show distinct habitat preference with respect to the nutrient level, were analyzed by a multifaceted approach. Microbial fingerprints obtained by PCR-SSCP (single-strand conformation polymorphism using universal, group-specific and functional primers were highly similar. Similarity was confirmed for colonization patterns obtained by fluorescence in situ hybridization (FISH coupled with confocal laser scanning microscopy (CLSM: Alphaproteobacteria were the main colonizers inside the hyaline cells of Sphagnum leaves. A deeper survey of Alphaproteobacteria by 16S rRNA gene amplicon sequencing reveals a high diversity with Acidocella, Acidisphaera, Rhodopila and Phenylobacterium as major genera for both mosses. Pathogen defense and nitrogen fixation are important functions of Sphagnum-associated bacteria, which are fulfilled by microbial communities of both Sphagna in a similar way. NifH libraries of Sphagnum-associated microbial communities were characterized by high diversity and abundance of Alphaproteobacteria but contained also diverse amplicons of other taxa, e.g. Cyanobacteria, Geobacter and Spirochaeta. Statistically significant differences between the microbial communities of both Sphagnum species could not be discovered in any of the experimental approach. Our results show that the same close relationship, which exists between the physical, morphological and chemical characteristics of Sphagnum mosses and the ecology and function of bog ecosystems, also connects moss plantlets with their associated bacterial communities.

  6. Biological N2 fixation mainly controlled by Sphagnum tissue N:P ratio in ombrotrophic bogs

    Science.gov (United States)

    Zivkovic, Tatjana; Moore, Tim R.

    2017-04-01

    Most of the 18 Pg nitrogen (N) accumulated in northern nutrient-poor and Sphagnum-dominated peatlands (bogs and fens) can be attributed to N2-fixation by diazotrophs either associated with the live Sphagnum or non-symbiotically in the deeper peat such as through methane consumption close to the water table. Where atmospheric N deposition is low (Sphagnum, suggested by the increase in tissue N:P to >16. It is unclear how Sphagnum-hosted diazotrophic activity may be affected by N deposition and thus changes in N:P ratio. First, we investigated the effects of long-term addition of different sources of nitrogen (0, 1.6, 3.2 and 6.4 g N m-2 y-1as NH4Cl and NaNO3), and phosphorus (5 g P m-2 y-1as KH2PO4) on Sphagnum nutrient status (N, P and N:P ratio), net primary productivity (NPP) and Sphagnum-associated N2fixation at Mer Bleue, a temperate ombrotrophic bog. We show that N concentration in Sphagnum tissue increased with larger rates of N addition, with a stronger effect on Sphagnum from NH4 than NO3. The addition of P created a 3.5 fold increase in Sphagnum P content compared to controls. Sphagnum NPP decreased linearly with the rise in N:P ratio, while linear growth declined exponentially with increase in Sphagnum N content. Rates of N2-fixation determined in the laboratory significantly decreased in response to even the smallest addition of both N species. In contrast, the addition of P increased N2 fixation by up to 100 times compared to N treatments and up to 5-30 times compared to controls. The change in N2-fixation was best modeled by the N:P ratio, across all experimental treatments. Secondly, to test the role of N:P ratio on N2-fixation across a range of bogs, eight study sites along the latitudinal gradient from temperate, boreal to subarctic zone in eastern Canada were selected. From each bog, two predominant microptopographies, hummocks and hollows, were tested for both N2-fixation activity in the laboratory and Sphagnum tissue concentrations of N, P and N

  7. Tangled history of the European uses of Sphagnum moss and sphagnol.

    Science.gov (United States)

    Drobnik, Jacek; Stebel, Adam

    2017-09-14

    Sphagnum mosses and peat could have been utilized as wound dressings for centuries, however reliable data on this subject are ambiguous; sometimes even no distinction between peat moss (Sphagnum spp.) and peat is made or these terms become confused. The first scientific account on surgical use of peat comes from 1882: a peat digger who successfully, by himself and in the way unknown to the then medicine, cured an open fracture of his forearm with peat. The peat, and very soon the peat moss itself (which is the major constituent of peat) drew attention of the 19th-century surgeons. We search for reliable information on: (1) inspirations for Sphagnum usage for medical purposes and its beginnings in the 19th century, (2) substances or products named sphagnol and their connections with (1); (3) on the origin of this name, (4) and on the occurrence of this name in medical sources. We have identified and studied published sources on the uses of peat-based and Sphagnum-based preparations and products of any processing level (including herbal stock, distillate, isolated pure or impure active principle, or a mixture of such) in surgery, pharmacy or cosmetics. A special attention was paid to the name sphagnol, which appeared many a time, in more than one context since 1899. Source publications were critically analysed from the taxonomical, pharmacognostical and ethnopharmacological points of view. Gathered data were cross-checked with the modern knowledge of the biologically active principles of Sphagnum and the prospects of their medical use. The application of peat in surgery started 1882. The use of peat moss as dressings was developed in the 1880's. It returned to surgical practice during WW1. The name sphagnol has two meanings: (1) A chemical substance isolated from the cell walls of Sphagnum mosses in 1899. A post-1950 research showed it to be a mixture of phenols dominated by sphagnum acid. (2) A product of dry distillation of peat contains solid and liquid fractions

  8. Detection, Isolation, and Characterization of Acidophilic Methanotrophs from Sphagnum Mosses ▿ †

    Science.gov (United States)

    Kip, Nardy; Ouyang, Wenjing; van Winden, Julia; Raghoebarsing, Ashna; van Niftrik, Laura; Pol, Arjan; Pan, Yao; Bodrossy, Levente; van Donselaar, Elly G.; Reichart, Gert-Jan; Jetten, Mike S. M.; Sinninghe Damsté, Jaap S.; Op den Camp, Huub J. M.

    2011-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions. Yet little is known about the diversity and identity of the methanotrophs present in and on Sphagnum mosses of peatlands, and only a few isolates are known. The methanotrophic community in Sphagnum mosses, originating from a Dutch peat bog, was investigated using a pmoA microarray. A high biodiversity of both gamma- and alphaproteobacterial methanotrophs was found. With Sphagnum mosses as the inoculum, alpha- and gammaproteobacterial acidophilic methanotrophs were isolated using established and newly designed media. The 16S rRNA, pmoA, pxmA, and mmoX gene sequences showed that the alphaproteobacterial isolates belonged to the Methylocystis and Methylosinus genera. The Methylosinus species isolated are the first acid-tolerant members of this genus. Of the acidophilic gammaproteobacterial strains isolated, strain M5 was affiliated with the Methylomonas genus, and the other strain, M200, may represent a novel genus, most closely related to the genera Methylosoma and Methylovulum. So far, no acidophilic or acid-tolerant methanotrophs in the Gammaproteobacteria class are known. All strains showed the typical features of either type I or II methanotrophs and are, to the best of our knowledge, the first isolated (acidophilic or acid-tolerant) methanotrophs from Sphagnum mosses. PMID:21724892

  9. Holocene climate variability revealed by oxygen isotope analysis of Sphagnum cellulose from Walton Moss, northern England

    Science.gov (United States)

    Daley, T. J.; Barber, K. E.; Street-Perrott, F. A.; Loader, N. J.; Marshall, J. D.; Crowley, S. F.; Fisher, E. H.

    2010-07-01

    Stable isotope analyses of Sphagnum alpha-cellulose, precipitation and bog water from three sites across northwestern Europe (Raheenmore, Ireland, Walton Moss, northern England and Dosenmoor, northern Germany) over a total period of 26 months were used to investigate the nature of the climatic signal recorded by Sphagnum moss. The δ18O values of modern alpha-cellulose tracked precipitation more closely than bog water, with a mean isotopic fractionation factor αcellulose-precipitation of 1.0274 ± 0.001 (1 σ) (≈27‰). Sub-samples of isolated Sphagnum alpha-cellulose were subsequently analysed from core WLM22, Walton Moss, northern England yielding a Sphagnum-specific isotope record spanning the last 4300 years. The palaeo-record, calibrated using the modern data, provides evidence for large amplitude variations in the estimated oxygen isotope composition of precipitation during the mid- to late Holocene. Estimates of palaeotemperature change derived from statistical relationships between modern surface air temperatures and δ18O precipitation values for the British Isles give unrealistically large variation in comparison to proxies from other archives. We conclude that use of such relationships to calibrate mid-latitude palaeo-data must be undertaken with caution. The δ18O record from Sphagnum cellulose was highly correlated with a palaeoecologically-derived index of bog surface wetness (BSW), suggesting a common climatic driver.

  10. Interploidal hybridization and mating patterns in the Sphagnum subsecundum complex.

    Science.gov (United States)

    Ricca, M; Szövényi, P; Temsch, E M; Johnson, M G; Shaw, A J

    2011-08-01

    Polyploidization is thought to result in instant sympatric speciation, but several cases of hybrid zones between one of the parental species and its polyploid derivative have been documented. Previous work showed that diploid Sphagnum lescurii is an allopolyploid derived from the haploids S. lescurii (maternal progenitor) and S. subsecundum (paternal progenitor). Here, we report the results from analyses of a population where allodiploid and haploid S. lescurii co-occur and produce sporophytes. We tested (i) whether haploids and diploids form hybrid triploid sporophytes; (ii) how hybrid and nonhybrid sporophytes compare in fitness; (iii) whether hybrid sporophytes form viable spores; (iv) the ploidy of any viable gametophyte offspring from hybrid sporophytes; (v) the relative viability of sporelings derived from hybrid and nonhybrid sporophytes; and (vi) if interploidal hybridization results in introgression between the allopolyploid and its haploid progenitor. We found that triploid hybrid sporophytes do occur and are larger than nonhybrid sporophytes, but exhibit very low germination percentages and produce sporelings that develop more slowly than those from nonhybrid sporophytes. All sporophytes attached to haploid gametophytes were triploid and were sired by diploid males, but all sporophytes attached to diploid gametophytes were tetraploid. This asymmetric pattern of interploidal hybridization is related to an absence of haploid male gametophytes in the population. Surprisingly, all sporelings from triploid sporophytes were triploid, yet were genetically variable, suggesting some form of aberrant meiosis that warrants further study. There was limited (but some) evidence of introgression between allodiploid and haploid S. lescurii. © 2011 Blackwell Publishing Ltd.

  11. Nutrient additions in pristine Patagonian Sphagnum bog vegetation : can phosphorus addition alleviate (the effects of) increased nitrogen loads

    NARCIS (Netherlands)

    Fritz, C.; Dijk, G. van; Smolders, A.J.P.; Pancotto, V.A.; Elzenga, J.T.M.; Roelofs, J.G.M.; Grootjans, A.P.

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear

  12. Methanotrophic activity and diversity in different Sphagnum magellanicum dominated habitats in the southernmost peat bogs of Patagonia

    NARCIS (Netherlands)

    Kip, N.; Fritz, C.; Langelaan, E. S.; Pan, Y.; Bodrossy, L.; Pancotto, V.; Jetten, M. S. M.; Smolders, A. J. P.; den Camp, H. J. M. Op

    2012-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methanotrophs living inside the dead hyaline cells or on the Sphagnum mosses are able to act as a methane filter and thereby reduce methane emissions. We investigated in situ methane concentrations and the corresponding activity and

  13. Regeneration and vegetative propagation of Sphagnum palustre as factor of population stability

    Directory of Open Access Journals (Sweden)

    Dygna Sobotka

    2015-01-01

    Full Text Available The stability of the Sphagnum palustre populations on the meadows of the Kampinos National Park situated north-west of Warsaw was investigated in the period 1971-1974. Laboratory cultures were also started to establish the regenerative ability of various gametophyte parts of Sphagnum: the main stem, branches, leaves and spore germination. The green stems and apical branches of the plants showed the highest regeneration ability. Brown stems and white branches developed less intensively. Leaves showed no tendency to develop into new plants. Gametophores were found to form quicker and more effectively by way of regeneration than from spores. In natural conditions more intensive growth of branchings (new shoots from the apical and green parts of Sphagnum was also observed, whereas the brown parts did not exhibit this ability.

  14. Sphagnum can 'filter' N deposition, but effects on the plant and pore water depend on the N form.

    Science.gov (United States)

    Chiwa, Masaaki; Sheppard, Lucy J; Leith, Ian D; Leeson, Sarah R; Tang, Y Sim; Cape, J Neil

    2016-07-15

    The ability of Sphagnum moss to efficiently intercept atmospheric nitrogen (N) has been assumed to be vulnerable to increased N deposition. However, the proposed critical load (20kgNha(-1)yr(-1)) to exceed the capacity of the Sphagnum N filter has not been confirmed. A long-term (11years) and realistic N manipulation on Whim bog was used to study the N filter function of Sphagnum (Sphagnum capillifolium) in response to increased wet N deposition. On this ombrotrophic peatland where ambient deposition was 8kgNha(-1)yr(-1), an additional 8, 24, and 56kgNha(-1)yr(-1) of either ammonium (NH4(+)) or nitrate (NO3(-)) has been applied for 11years. Nutrient status of Sphagnum and pore water quality from the Sphagnum layer were assessed. The N filter function of Sphagnum was still active up to 32kgNha(-1)yr(-1) even after 11years. N saturation of Sphagnum and subsequent increases in dissolved inorganic N (DIN) concentration in pore water occurred only for 56kgNha(-1)yr(-1) of NH4(+) addition. These results indicate that the Sphagnum N filter is more resilient to wet N deposition than previously inferred. However, functionality will be more compromised when NH4(+) dominates wet deposition for high inputs (56kgNha(-1)yr(-1)). The N filter function in response to NO3(-) uptake increased the concentration of dissolved organic N (DON) and associated organic anions in pore water. NH4(+) uptake increased the concentration of base cations and hydrogen ions in pore water though ion exchange. The resilience of the Sphagnum N filter can explain the reported small magnitude of species change in the Whim bog ecosystem exposed to wet N deposition. However, changes in the leaching substances, arising from the assimilation of NO3(-) and NH4(+), may lead to species change. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-04-01

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

  16. Bioaccumulation and glutathione-mediated detoxification of copper and cadmium in Sphagnum squarrosum Crome Samml.

    Science.gov (United States)

    Saxena, Anuj; Saxena, Anjali

    2012-07-01

    Physiological and biochemical responses, metal bioaccumulation and tolerance potential of Sphagnum squarrosum Crome Samml. to Cu and Cd were studied to determine its bioindication and bioremediation potential. Results suggest that glutathione treatment increases the metal accumulation potential and plays a definite role in heavy metal scavenging. High abundance of Sphagnum in metal-rich sites strongly suggests its high metal tolerance capabilities. This experiment demonstrates that S. squarrosum is able to accumulate and tolerate a high amount of metals and feasibility of its application as bioindicator and remediator test species of metal-contaminated environment.

  17. Alternative substrates to the sphagnum moss in the acclimatization of arundina graminifolia “alba”(Orchidaceae)

    OpenAIRE

    Ana Paula Zandoná; Ricardo Tadeu de Faria; Alessandro Borini Lone; Rodrigo Thibes Hoshino

    2014-01-01

    The Arundina graminifolia, is popularly known as bamboo orchid, by having their stems quite extensive. It is widely used in the business landscape, with a very rustic plant. Sphagnum moss is the most widely used substrate in the acclimatization of orchids, but environmental issues have led to an increase in the search for alternative substrates. The objective of this study was to evaluate substrates that can replace all or part of the use of sphagnum moss on the acclimatization of A. graminif...

  18. Water flow in Sphagnum hummocks: Mesocosm measurements and modelling

    Science.gov (United States)

    Price, Jonathan S.; Whittington, Peter N.

    2010-02-01

    SummaryThe internal water fluxes within Sphagnum mosses critically affect the rate of evaporation and the wetness of the living upper few centimetres of moss (capitula) and the physiological processes (e.g. photosynthesis) that support them. To quantify water fluxes and stores in Sphagnum rubellum hummocks we used a 30 cm high column (mesocosm) of undisturbed hummock moss including the capitula, and applied a number of experiments to investigate (1) staged lowering (and raising) of the water table ( wt) with a manometer tube; (2) pumped seepage of about 0.7 cm d -1 to produce a wt drop of 1.5 cm day -1; and (3) evaporation averaging 3.2 mm d -1. Water content ( θ) at saturation ( θ s) was ˜0.9 cm 3 cm -3 for all depths. Residual water content ( θ r) was 0.2 cm 3 cm -3 at 5 cm depth, increasing to 0.47 cm 3 cm -3 at 25 cm depth. Hydraulic conductivity ( K) of the same top 5 cm layer ranged from 1.8 × 10 -3 m s -1 at θ s to 4 × 10 -8 m s -1 at θ r. By comparison K at 25 cm depth had a much more limited range from 2.3 × 10 -4 m s -1 at θ s to 1.1 × 10 -5 m s -1 at θ r. Staged wt lowering from -10 cm to -30 cm (no evaporation allowed) resulted in an abrupt change in θ that reached a stable value generally within an hour, indicating the responsiveness of moss to drainage. Staged increases also resulted in an abrupt rise in θ, but in some cases several days were required for θ to equilibrate. Pumped seepage resulted in a sequential decline of θ, requiring about 10 days for each layer to reach θ r after the water table dropped below the sensor at the respective depths. Evaporation resulted in a similar pattern of decline but took almost three times as long. The computer simulation Hydrus 1D was used to model the fluxes and provided a good fit for the staged lowering and pumped seepage experiments, but overestimated the water loss by evaporation. We believe the reason for this is that over the longer evaporation experiment, the monolith underwent

  19. Ion exchange in sphagnum and its relation to bog ecology

    Energy Technology Data Exchange (ETDEWEB)

    Clymo, R S

    1963-01-01

    In sphagnum cuspidatum unesterified polyuronic acids form 12 percent of the dry weight; in S. acutifolium 25 percent of the dry weight. A good correlation has been found for sphagna between the content of unesterified polyuronic acid and the cation exchange ability, and between cation exchange ability and height of normal habitat above the water table. Anion exchange ability in sphagna is less than 0.0026 m.eq./g. d.w. compared with about 1.2 m.eq./g. d.w. for cations at pH values above 7. In natural conditions the exchange sites are, however, only partly dissociated. The production of new plant material in a bog dependent on rainwater for nurients can be sufficient to maintain the pH below 4.5, but on other than H/sup +/ could be retained in exchangeable form. A greater proportion of polyvalent cations could be retained. The kinetics of cation exchange are consistent with a heterogeneous exchange phase containing regions of high charge density and regions with lower charge density. At equilibrium the proportions of different cations in the exchange phase are largely explicable by a Donnan distribution, but there are notable exceptions. Two estimates based on donnan distribution suggest that with low external pH and/or low cation concentration the apparent concentration of exchange sites may be 2-3 eq./l., falling with rise in pH and/or increase in cation concentration to 0.9 -1.5 eq./l. The apparent dissociation coefficient also varies in these conditions from 2 x 10/sup -3/ to 1 x 10/sup -4/.

  20. Characteristics of Eastern Canadian cultivated Sphagnum and potential use as a substitute for perlite and vermiculite in peat-based horticultural substrates

    Directory of Open Access Journals (Sweden)

    M. Aubé

    2015-03-01

    Full Text Available Sphagnum cultivation on harvested peatlands to meet wetland restoration objectives could be an economically feasible activity since cultivated Sphagnum has potential horticultural applications. We compared the characteristics of cultivated Sphagnum from Shippagan (Canada with those of non-cultivated Sphagnum products from Chile, New Zealand and Canada, and assessed its potential as a perlite and vermiculite substitute in horticultural peat-based substrates. Shippagan cultivated Sphagnum was shorter than the Chilean and New Zealand products with which it was compared, yet more similar to them than to the Canadian product currently on the market. Laboratory tests on physical properties and greenhouse growth trials indicated that 50–100 % of the perlite or vermiculite of a peat-based substrate can be successfully replaced with cultivated Sphagnum. Non-sieved coarsely shredded Sphagnum or the large (> 6.3 mm fragments of sieved coarsely shredded Sphagnum best replicated the aeration provided by perlite and vermiculite in the substrates that were tested. Decomposition tests and comparisons of changes in physical properties of substrates containing Sphagnum after six weeks of growth trials indicated that Sphagnum degradation leading to reduced substrate performance is not likely to be an issue. Therefore, cultivated Sphagnum has great potential as a substitute for perlite and vermiculite.

  1. Mosses as indicators of atmospheric metal deposition in an industrial area of southern Brazil Musgos como indicadores da deposição atmosférica de metais em uma área industrial do sul do Brasil

    Directory of Open Access Journals (Sweden)

    Aline Correa Mazzoni

    2012-09-01

    Full Text Available Caxias do Sul hosts the second largest metal-mechanic pole in Brazil, which increases the risk of atmospheric contamination. With the aim of identifying species that might be useful as indicators of atmospheric deposition of metals, 15 species of mosses from an urban and a rural setting were analyzed and compared with specimens deposited at the Herbarium of the Universidade de Caxias do Sul. Metal concentrations (Zn, Ni, Cd, Cr, Cu and Pb were determined using Atomic Absorption Spectrometry (AAS. The Mann-Whitney test indicated concentrations of Zn, Cu, Pb and Cr that were significantly different between the urban and rural areas. Additionally, Concentrations of Zn, Cd, Cu and Pb were significantly higher in recently collected samples. The species Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid. E. Britton, Helicodontium capillare (Hedw. A. Jaeger, Schlotheimia jamesonii (W.-Arnott Brid. and Meteorium deppei (Hornsch. ex Müll. Hal. Mitt. are potential biomonitors of atmospheric metal deposition.Caxias do Sul sedia o segundo maior pólo metal mecânico do Brasil, apresentando elevado risco de contaminação atmosférica. Com o objetivo de identificar espécies úteis como indicadoras da deposição atmosférica de metais, foram analisadas 15 espécies de musgos procedentes da zona urbana e da área rural e espécimens depositados no Herbário da Universidade de Caxias do Sul. Os metais (Zn, Ni, Cd, Cr, Cu e Pb foram determinados por meio de Espectrometria de Absorção Atômica (AAS. O Teste de Mann-Whitney indicou diferenças significativas nas concentrações de Zn, Cu, Pb e Cr entre as áreas urbana e rural. Um aumento significativo na presença de Zn, Cd, Cu e Pb foi evidenciado nas amostras recentes. As espécies Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid. E. Britton, Helicodontium capillare (Hedw. A. Jaeger, Schlotheimia jamesonii (W.-Arnott Brid. e Meteorium deppei (Hornsch. ex Müll. Hal. Mitt. são indicadas

  2. Clonal in vitro propagation of peat mosses (Sphagnum L.) as novel green resources for basic and applied research.

    Science.gov (United States)

    Beike, Anna K; Spagnuolo, Valeria; Lüth, Volker; Steinhart, Feray; Ramos-Gómez, Julia; Krebs, Matthias; Adamo, Paola; Rey-Asensio, Ana Isabel; Angel Fernández, J; Giordano, Simonetta; Decker, Eva L; Reski, Ralf

    As builders and major components of peatlands, Sphagnopsida (peat mosses) are very important organisms for ecosystems and world's climate. Nowadays many Sphagnum species as well as their habitats are largely protected, while their scientific and economic relevance remains considerable. Advanced methods of in vitro cultivation provide the potential to work in a sustainable way with peat mosses and address aspects of basic research as well as biotechnological and economical topics like biomonitoring or the production of renewable substrates for horticulture ( Sphagnum farming). Here, we describe the establishment of axenic in vitro cultures of the five peat moss species Sphagnum fimbriatum Wils. and Hook., Sphagnum magellanicum Brid., Sphagnum palustre L., Sphagnum rubellum Wils. and Sphagnum subnitens Russ. and Warnst. with specific focus on large-scale cultivation of S. palustre in bioreactors. Axenic, clonal cultures were established to produce high quantities of biomass under standardized laboratory conditions. For advanced production of S. palustre we tested different cultivation techniques, growth media and inocula, and analyzed the effects of tissue disruption. While cultivation on solid medium is suitable for long term storage, submerse cultivation in liquid medium yielded highest amounts of biomass. By addition of sucrose and ammonium nitrate we were able to increase the biomass by around 10- to 30-fold within 4 weeks. The morphology of in vitro-cultivated gametophores showed similar phenotypic characteristics compared to material from the field. Thus the tested culture techniques are suitable to produce S. palustre material for basic and applied research.

  3. Nutrient additions in pristine Patagonian Sphagnum bog vegetation: can phosphorus addition alleviate (the effects of) increased nitrogen loads.

    Science.gov (United States)

    Fritz, C; van Dijk, G; Smolders, A J P; Pancotto, V A; Elzenga, T J T M; Roelofs, J G M; Grootjans, A P

    2012-05-01

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear whether P-addition can alleviate physiological N-stress in Sphagnum plants. A 3-year fertilisation experiment was conducted in lawns of a pristine Sphagnum magellanicum bog in Patagonia, where competing vascular plants were practically absent. Background wet deposition of nitrogen was low (≈ 0.1-0.2 g · N · m(-2) · year(-1)). Nitrogen (4 g · N · m(-2) · year(-1)) and phosphorus (1 g · P · m(-2) · year(-1)) were applied, separately and in combination, six times during the growing season. P-addition substantially increased biomass production of Sphagnum. Nitrogen and phosphorus changed the morphology of Sphagnum mosses by enhancing height increment, but lowering moss stem density. In contrast to expectations, phosphorus failed to alleviate physiological stress imposed by excess nitrogen (e.g. amino acid accumulation, N-saturation and decline in photosynthetic rates). We conclude that despite improving growth conditions by P-addition, Sphagnum-bog ecosystems remain highly susceptible to nitrogen additions. Increased susceptibility to desiccation by nutrients may even worsen the negative effects of excess nitrogen especially in windy climates like in Patagonia. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe.

    Science.gov (United States)

    Jiroušek, Martin; Hájek, Michal; Bragazza, Luca

    2011-02-01

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m(-2) year(-1) in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Long-term interactive effects of N addition with P and K availability on N status of Sphagnum.

    Science.gov (United States)

    Chiwa, Masaaki; Sheppard, Lucy J; Leith, Ian D; Leeson, Sarah R; Tang, Y Sim; Neil Cape, J

    2018-06-01

    Little information exists concerning the long-term interactive effect of nitrogen (N) addition with phosphorus (P) and potassium (K) on Sphagnum N status. This study was conducted as part of a long-term N manipulation on Whim bog in south Scotland to evaluate the long-term alleviation effects of phosphorus (P) and potassium (K) on N saturation of Sphagnum (S. capillifolium). On this ombrotrophic peatland, where ambient deposition was 8 kg N ha -1 yr -1 , 56 kg N ha -1 yr -1 of either ammonium (NH 4 + , N red ) or nitrate (NO 3 - , N ox ) with and without P and K, were added over 11 years. Nutrient concentrations of Sphagnum stem and capitulum, and pore water quality of the Sphagnum layer were assessed. The N-saturated Sphagnum caused by long-term (11 years) and high doses (56 kg N ha -1 yr -1 ) of reduced N was not completely ameliorated by P and K addition; N concentrations in Sphagnum capitula for N red 56 PK were comparable with those for N red 56, although N concentrations in Sphagnum stems for N red 56 PK were lower than those for N red 56. While dissolved inorganic nitrogen (DIN) concentrations in pore water for N red 56 PK were not different from N red 56, they were lower for N ox 56 PK than for N ox 56 whose stage of N saturation had not advanced compared to N red 56. These results indicate that increasing P and K availability has only a limited amelioration effect on the N assimilation of Sphagnum at an advanced stage of N saturation. This study concluded that over the long-term P and K additions will not offset the N saturation of Sphagnum. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Response of a Sphagnum bog plant community to elevated CO2 and N supply

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Klees, H.; Visser, de W.; Berendse, F.

    2002-01-01

    The response of plant growth to rising CO2 levels appears to depend on nutrient availability, but it is not known whether the growth of bog plants reacts similarly. We therefore studied the effects of elevated CO2 in combination with N supply on the growth of Sphagnum mosses and vascular plants in

  7. Sphagnum mosses : Masters of efficient N-uptake while avoiding intoxication

    NARCIS (Netherlands)

    Fritz, Christian; Lamers, Leon P.M.; Riaz, Muhammed; van den Berg, Leon J.L.; Elzenga, Theo J.T.M.

    2014-01-01

    Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant

  8. Sphagnum modifies climate-change impacts on subarctic vascular bog plants.

    NARCIS (Netherlands)

    Dorrepaal, E.; Aerts, R.; Cornelissen, J.H.C.; van Logtestijn, R.S.P; Callaghan, T.V.

    2006-01-01

    1. Vascular plant growth forms in northern peatlands differ in their strategies to cope with the harsh climate, low nutrient availability and progressively increasing height of the Sphagnum carpet in which they grow. Climate change may therefore affect growth forms differentially, both directly and

  9. [Analysis of the bacterial community developing in the course of Sphagnum moss decomposition].

    Science.gov (United States)

    Kulichevskaia, I S; Belova, S E; Kevbrin, V V; Dedysh, S N; Zavarzin, G A

    2007-01-01

    Slow degradation of organic matter in acidic Sphagnum peat bogs suggests a limited activity of organotrophic microorganisms. Monitoring of the Sphagnum debris decomposition in a laboratory simulation experiment showed that this process was accompanied by a shift in the water color to brownish due to accumulation of humic substances and by the development of a specific bacterial community with a density of 2.4 x 10(7) cells ml(-1). About half of these organisms are metabolically active and detectable with rRNA-specific oligonucleotide probes. Molecular identification of the components of this microbial community showed the numerical dominance of bacteria affiliated with the phyla Alphaproteobacteria, Actinobacteria, and Phanctomycetes. The population sizes of Firmicutes and Bacteroidetes, which are believed to be the main agents of bacterially-mediated decomposition in eutrophic wetlands, were low. The numbers of planctomycetes increased at the final stage of Sphagnum decomposition. The representative isolates of Alphaproteobacteria were able to utilize galacturonic acid, the only low-molecular-weight organic compound detected in the water samples; the representatives of Planctomycetes were able to decompose some heteropolysaccharides, which points to the possible functional role of these groups of microorganisms in the community under study. Thus, the composition of the bacterial community responsible for Sphagnum decomposition in acidic and low-mineral oligotrophic conditions seems to be fundamentally different from that of the bacterial community which decomposes plant debris in eutrophic ecosystems at neutral pH.

  10. The trapping of fly-ash particles in the surface layers of Sphagnum-dominated peat

    International Nuclear Information System (INIS)

    Punning, J.-M.; Alliksaar, T.

    1997-01-01

    The movement of fly-ash particles in a sequence of Sphagnum moss was studied in laboratory experiments and field investigations. Fly ash was obtained from the electrostatic precipitators of the Estonian Thermal Power Plant operating on oil shale. The data obtained in the laboratory show that only 0.8% of particles, placed on the surface of a 6-10 cm thick Sphagnum layer, were washed out with water (700-750 mm) during the 241 days of the experiment. The majority of added particles were fixed in the upper part (90% in 1-3 cm) of the moss layer. A SEM study indicates that sorption is slightly species-dependent due to the micromorphological parameters of the Sphagnum species. The storage of particles by Sphagnum mosses allows the use of natural sequences to study the history of atmospheric pollution. The distribution of particles in the upper part of moss layers in Viru Bog (50 km east of Tallinn, North Estonia) shows good agreement with the known air pollution history in Tallinn. 13 refs., 6 figs., 2 tabs

  11. The interaction between epiphytic algae, a parasitic fungus and Sphagnum as affected by N. and P.

    NARCIS (Netherlands)

    Limpens, J.; Jeffrey, T.A.G.; Baar, J.; Berendse, F.; Zijlstra, J.D.

    2003-01-01

    We report the effects of fertilisation with N and P on the infection of Sphagnum by its fungal parasite Lyophyllum palustre, the expansion of epiphytic algae and the interaction between the latter two from 1998 to 2001. We added 40 kg N ha(-1) yr(-1) or 3 kg P ha(-1) yr(-1) in a full factorial

  12. Exploding a myth: the capsule dehiscence mechanism and the function of pseudostomata in Sphagnum.

    Science.gov (United States)

    Duckett, Jeffrey G; Pressel, Silvia; P'ng, Ken M Y; Renzaglia, Karen S

    2009-01-01

    The nineteenth century air-gun explanation for explosive spore discharge in Sphagnum has never been tested experimentally. Similarly, the function of the numerous stomata ubiquitous in the capsule walls has never been investigated. Both intact and pricked Sphagnum capsules, that were allowed to dry out, all dehisced over an 8-12 h period during which time the stomatal guard cells gradually collapsed and their potassium content, measured by X-ray microanalysis in a cryoscanning electron microscope, gradually increased. By contrast, guard cell potassium fell in water-stressed Arabidopsis. The pricking experiments demonstrate that the air-gun notion for explosive spore discharge in Sphagnum is inaccurate; differential shrinkage of the capsule walls causes popping off the rigid operculum. The absence of evidence for a potassium-regulating mechanism in the stomatal guard cells and their gradual collapse before spore discharge indicates that their sole role is facilitation of sporophyte desiccation that ultimately leads to capsule dehiscence. Our novel functional data on Sphagnum, when considered in relation to bryophyte phylogeny, suggest the possibility that stomata first appeared in land plants as structures that facilitated sporophyte drying out before spore discharge and only subsequently acquired their role in the regulation of gaseous exchange.

  13. Decomposition of Carex and Sphagnum litter in two mesotrophic fens differing in dominant plant species

    NARCIS (Netherlands)

    Scheffer, R.A.; Van Logtestijn, R. S P; Verhoeven, J. T A

    2001-01-01

    Peatlands can be classified into fens and bogs based on their hydrology. Development of fens to bogs is accompanied by the invasion of Sphagnum species. The purpose of this study was to determine how the decomposition process in fens is influenced by the transition from a vascular plant-dominated

  14. Ecohydrology of a Sphagnum peatland in transitional climate - an interdysciplinary study

    Science.gov (United States)

    Słowińska, S.; Słowiński, M.; Lamentowicz, M.; Skrzypek, G.

    2012-04-01

    Sphagnum peatlands of the Central Europe are regarded as the valuable and endangered habitats. Their existence depends on the complex climatic, hydrological, topographical and botanical conditions. Good understanding of peatlands' ecohydrology is crucial for the appropriate environmental management. Our long-term ecological study is focused on a poor fen located in Northern Poland - a unique floristic nature reserve and Nature 2000 area. Main aims of the research were to: a) understand an influence of the temperature and precipitation on the ground water, b) explain an impact of the local climate and the groundwater table level on testate amoebae communities, Sphagnum mosses growth and stable carbon, nitrogen and oxygen isotope compositions, c) use the neo- ecological data for the quantitative palaeoecological reconstructions. We have been conducting the monitoring of the growth of Sphagnum mosses in five plots. Vegetation was sampled three times during the growing season for the stable isotope and testate amoebae analyses (July, September and December 2009). Temperature of the air and acrotelm, air humidity, precipitation and groundwater table were recorded using automatic data loggers. Our research confirmed that even small fluctuation of temperature, precipitation and annual distribution of precipitation have a very strong impact on the hydrology of the peatland. Testate amoeba communities and stable isotopes from Sphagnum clearly indicated the hydrological response of the mire in the different parts of the peatland. The next step is a detailed seasonal study supported by the manipulative warming experiment.

  15. Response of Sphagnum species mixtures to increased temperature and nitrogen availability

    NARCIS (Netherlands)

    Breeuwer, A.J.G.; Heijmans, M.M.P.D.; Berendse, F.; Gleichman, J.M.; Robroek, B.J.M.; Limpens, J.

    2009-01-01

    To predict the role of ombrotrophic bogs as carbon sinks in the future, it is crucial to understand how Sphagnum vegetation in bogs will respond to global change. We performed a greenhouse experiment to study the effects of two temperature treatments (17.5 and 21.7°C) and two N addition treatments

  16. Expansion of Sphagnum fallax in bogs: striking the ballance between N and P availability

    NARCIS (Netherlands)

    Limpens, J.; Tomassen, H.B.M.; Berendse, F.

    2003-01-01

    Nitrogen deposition may cause shifts in the Sphagnum species composition of bogs, ultimately affecting the conservation value of these systems. We studied the effects of N and P on the expansion of S. fallax and S. flexuosum in bogs. We related historical census data of S. fallax, S. flexuosum, and

  17. Major and trace elements in Sphagnum moss from four southern German bogs, and comparison with available moss monitoring data

    OpenAIRE

    KEMPTER HEIKE; KRACHLER MICHAEL; SHOTYK W.; ZACCONE CLAUDIO

    2017-01-01

    In this paper, we present concentrations of an array of major and trace elements (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Rb, Sb, Sc, Sr, Th, Tl, U, V, Zn) in living Sphagnum mosses from four southern German bogs and compare them with moss monitoring data of the respective regions. To do this, Sphagnum mosses were collected in Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year la...

  18. Sphagnum mosses--masters of efficient N-uptake while avoiding intoxication.

    Science.gov (United States)

    Fritz, Christian; Lamers, Leon P M; Riaz, Muhammad; van den Berg, Leon J L; Elzenga, Theo J T M

    2014-01-01

    Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form ((15)N-ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5-6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands.

  19. Sphagnum Mosses - Masters of Efficient N-Uptake while Avoiding Intoxication

    Science.gov (United States)

    Fritz, Christian; Lamers, Leon P. M.; Riaz, Muhammad; van den Berg, Leon J. L.; Elzenga, Theo J. T. M.

    2014-01-01

    Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form (15N - ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5–6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands

  20. Physiological responses to nitrogen and sulphur addition and raised temperature in Sphagnum balticum.

    Science.gov (United States)

    Granath, Gustaf; Wiedermann, Magdalena M; Strengbom, Joachim

    2009-09-01

    Sphagnum, the main genus which forms boreal peat, is strongly affected by N and S deposition and raised temperature, but the physiological mechanisms behind the responses are largely unknown. We measured maximum photosynthetic rate (NP(max)), maximum efficiency of photosystem II [variable fluorescence (F (v))/maximum fluorescence yield (F (m))] and concentrations of N, C, chlorophyll and carotenoids as responses to N and S addition and increased temperature in Sphagnum balticum (a widespread species in the northern peatlands) in a 12-year factorial experiment. NP(max) did not differ between control (0.2 g N m(-2) year(-1)) and high N (3.0 g N m(-2) year(-1)), but was higher in the mid N treatment (1.5 g N m(-2) year(-1)). N, C, carotenoids and chlorophyll concentration increased in shoot apices after N addition. F (v)/F (m) did not differ between N treatments. Increased temperature (+3.6 degrees C) had a small negative effect on N concentration, but had no significant effect on NP(max) or F (v)/F (m). Addition of 2 g S m(-2) year(-1) showed a weak negative effect on NP(max) and F (v)/F (m). Our results suggest a unimodal response of NP(max) to N addition and tissue N concentration in S. balticum, with an optimum N concentration for photosynthetic rate of ~13 mg N g(-1). In conclusion, high S deposition may reduce photosynthetic capacity in Sphagnum, but the negative effects may be relaxed under high N availability. We suggest that previously reported negative effects on Sphagnum productivity under high N deposition are not related to negative effects on the photosynthetic apparatus, but differences in optimum N concentration among Sphagnum species may affect their competitive ability under different N deposition regimes.

  1. Metal and proton adsorption capacities of natural and cloned Sphagnum mosses.

    Science.gov (United States)

    Gonzalez, Aridane G; Pokrovsky, Oleg S; Beike, Anna K; Reski, Ralf; Di Palma, Anna; Adamo, Paola; Giordano, Simonetta; Angel Fernandez, J

    2016-01-01

    Terrestrial mosses are commonly used as bioindicators of atmospheric pollution. However, there is a lack of standardization of the biomonitoring preparation technique and the efficiency of metal adsorption by various moss species is poorly known. This is especially true for in vitro-cultivated moss clones, which are promising candidates for a standardized moss-bag technique. We studied the adsorption of copper and zinc on naturally grown Sphagnum peat moss in comparison with in vitro-cultivated Sphagnum palustre samples in order to provide their physico-chemical characterization and to test the possibility of using cloned peat mosses as bioindicators within the protocol of moss-bag technique. We demonstrate that in vitro-grown clones of S. palustre exhibit acid-base properties similar to those of naturally grown Sphagnum samples, whereas the zinc adsorption capacity of the clones is approx. twice higher than that of the samples from the field. At the same time, the field samples adsorbed 30-50% higher amount of Cu(2+) compared to that of the clones. This contrast may be related to fine differences in the bulk chemical composition, specific surface area, morphological features, type and abundance of binding sites at the cell surfaces and in the aqueous solution of natural and cloned Sphagnum. The clones exhibited much lower concentration of most metal pollutants in their tissues relative to the natural samples thus making the former better indicators of low metal loading. Overall, in vitro-produced clones of S. palustre can be considered as an adequate, environmentally benign substitution for protected natural Sphagnum sp. samples to be used in moss-bags for atmospheric monitoring. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Alternative substrates to the sphagnum moss in the acclimatization of arundina graminifolia “alba”(Orchidaceae

    Directory of Open Access Journals (Sweden)

    Ana Paula Zandoná

    2014-09-01

    Full Text Available The Arundina graminifolia, is popularly known as bamboo orchid, by having their stems quite extensive. It is widely used in the business landscape, with a very rustic plant. Sphagnum moss is the most widely used substrate in the acclimatization of orchids, but environmental issues have led to an increase in the search for alternative substrates. The objective of this study was to evaluate substrates that can replace all or part of the use of sphagnum moss on the acclimatization of A. graminifolia. The substrates used were: sphagnum moss, rice hulls, rice hulls + coir 1:1 (v / v sphagnum + carbonized rice husk, 1:1 (v / v. Seedlings were kept in a greenhouse and after seven months were evaluated for survival rate (%, shoot height (cm, average root length (cm, number of leaves and roots, dry leaves, pseudobulbs and roots (g and leaf area (mm2. Also evaluated were pH, conductivity (uS.cm-1, density (g.cm-3 and water holding capacity (mL.L-1 were evaluated. The results showed high levels of survival (80% and the number of leaves (4.3 grown plants in rice hulls + coconut fiber 1:1 (v / v. The same with respect to pH (5.9 within the optimal range of nutrient availability. It is concluded that the mixture of rice hulls + coconut fiber 1:1 (v / v, is a suitable substrate for plant growth A. graminifolia during the acclimatization phase, which may replace the sphagnum, and the use of carbonized rice husk alone unfeasible during this period.

  3. A Novel Framework for Quantifying past Methane Recycling by Sphagnum-Methanotroph Symbiosis Using Carbon and Hydrogen Isotope Ratios of Leaf Wax Biomarkers

    Science.gov (United States)

    Nichols, Jonathan E.; Isles, Peter D. F.; Peteet, Dorothy M.

    2014-01-01

    The concentration of atmospheric methane is strongly linked to variations in Earth's climate. Currently, we can directly reconstruct the total atmospheric concentration of methane, but not individual terms of the methane cycle. Northern wetlands, dominated by Sphagnum, are an important contributor of atmospheric methane, and we seek to understand the methane cycle in these systems. We present a novel method for quantifying the proportion of carbon Sphagnum assimilates from its methanotrophic symbionts using stable isotope ratios of leaf-wax biomarkers. Carbon isotope ratios of Sphagnum compounds are determined by two competing influences, water content and the isotope ratio of source carbon. We disentangled these effects using a combined hydrogen and carbon isotope approach. We constrained Sphagnum water content using the contrast between the hydrogen isotope ratios of Sphagnum and vascular plant biomarkers. We then used Sphagnum water content to calculate the carbon isotope ratio of Sphagnum's carbon pool. Using a mass balance equation, we calculated the proportion of recycled methane contributed to the Sphagnum carbon pool, 'PRM.' We quantified PRM in peat monoliths from three microhabitats in the Mer Bleue peatland complex. Modern studies have shown that water table depth and vegetation have strong influences on the peatland methane cycle on instrumental time scales. With this new approach, delta C-13 of Sphagnum compounds are now a useful tool for investigating the relationships among hydrology, vegetation, and methanotrophy in Sphagnum peatlands over the time scales of entire peatland sediment records, vital to our understanding of the global carbon cycle through the Late Glacial and Holocene.

  4. Validating modelled data on major and trace element deposition in southern Germany using Sphagnum moss

    Science.gov (United States)

    Kempter, Heike; Krachler, Michael; Shotyk, William; Zaccone, Claudio

    2017-10-01

    Sphagnum mosses were collected from four ombrotrophic bogs in two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year later, plant matter was harvested and productivity determined. Major and trace element concentrations (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sc, Sr, Th, Ti, Tl, U, V, Zn) were determined in acid digests using sector field ICP-MS. Up to 12 samples (40 × 40 cm) were collected per site, and 6-10 sites investigated per bog. Variation in element accumulation rates within a bog is mostly the result of the annual production rate of the Sphagnum mosses which masks not only the impact of site effects, such as microtopography and the presence of dwarf trees, but also local and regional conditions, including land use in the surrounding area, topography, etc. The difference in productivity between peat bogs results in distinctly higher element accumulation rates at the NBF bogs compared to those from OB for all studied elements. The comparison with the European Monitoring and Evaluation Program (EMEP; wet-only and total deposition) and Modelling of Air Pollutants and Ecosystem Impact (MAPESI; total deposition) data shows that accumulation rates obtained using Sphagnum are in the same range of published values for direct measurements of atmospheric deposition of As, Cd, Cu, Co, Pb, and V in both regions. The accordance is very dependent on how atmospheric deposition rates were obtained, as different models to calculate the deposition rates may yield different fluxes even for the same region. In future studies of atmospheric deposition of trace metals, both Sphagnum moss and deposition collectors have to be used on the same peat bog and results compared. Antimony, however, shows considerable discrepancy, because it is either under-estimated by Sphagnum moss or over-estimated by both atmospheric deposition

  5. Establishing Sphagnum cultures on bog grassland, cut-over bogs, and floating mats: procedures, costs and area potential in Germany

    Directory of Open Access Journals (Sweden)

    S. Wichmann

    2017-04-01

    Full Text Available Sphagnum biomass is valued as a high-quality constituent of horticultural growing media. The cultivation of Sphagnum (peatmoss was tested successfully on peat soil and on artificial mats floating on acidic water bodies. But whether Sphagnum farming is economically feasible is unclear. Drawing on experience gained during four research projects in Germany we compared the procedures, costs and area potential for establishing large-scale Sphagnum cultures. Establishment costs were clearly lower for soil-based cultivation (€8.35 m-2 to €12.80 m 2 than for water-based cultivation (€17.34 m-2 to €21.43 m-2. Relating costs to the predicted dry mass yield over the total cultivation time resulted in values of €1,723 t-1 on cut-over bog, €2,646 t-1 on former bog grassland, €9,625 t -1 on floating mats without pre-cultivation and €11,833 t-1 on pre-cultivated Sphagnum mats. The high production costs of the mats (without pre-cultivation 54 % and with pre-cultivation 63 % of total costs resulted in the highest overall costs. In the case of soil-based Sphagnum cultures, the costs of purchasing Sphagnum diaspores were most influential (on bog grassland 46 % and on cut-over bog 71 % of total costs. The lowest costs relate to cut-over bog because of the smaller effort required for site preparation compared to taking off the topsoil of former bog grassland and the limited costs for the assumed irrigation system. In the case of former bog grassland, the high investment costs for the project-specific automatic water management boosted the establishment costs. Taking into account potential savings on the irrigation system and the high area potential, bog grassland emerges as the most promising land category for Sphagnum farming in Germany.

  6. Relative importance of local habitat complexity and regional factors for assemblages of oribatid mites (Acari: Oribatida) in Sphagnum peat bogs.

    Science.gov (United States)

    Minor, M A; Ermilov, S G; Philippov, D A; Prokin, A A

    2016-11-01

    We investigated communities of oribatid mites in five peat bogs in the north-west of the East European plain. We aimed to determine the extent to which geographic factors (latitude, separation distance), local environment (Sphagnum moss species, ground water level, biogeochemistry) and local habitat complexity (diversity of vascular plants and bryophytes in the surrounding plant community) influence diversity and community composition of Oribatida. There was a significant north-to-south increase in Oribatida abundance. In the variance partitioning, spatial factors explained 33.1 % of variability in abundance across samples; none of the environmental factors were significant. Across all bogs, Oribatida species richness and community composition were similar in Sphagnum rubellum and Sphagnum magellanicum, but significantly different and less diverse in Sphagnum cuspidatum. Sphagnum microhabitat explained 52.2 % of variability in Oribatida species richness, whereas spatial variables explained only 8.7 %. There was no distance decay in community similarity between bogs with increased geographical distance. The environmental variables explained 34.9 % of the variance in community structure, with vascular plants diversity, bryophytes diversity, and ground water level all contributing significantly; spatial variables explained 15.1 % of the total variance. Overall, only 50 % of the Oribatida community variance was explained by the spatial structure and environmental variables. We discuss relative importance of spatial and local environmental factors, and make general inferences about the formation of fauna in Sphagnum bogs.

  7. Effect of crustose lichen on soil CO2 efflux in sphagnum moss regime of tundra, west Alaska

    Science.gov (United States)

    Kim, Y.; Park, S. J.; Suzuki, R.; Lee, B. Y.

    2017-12-01

    Increasing ambient temperatures across the Arctic have induced changes in plant extent and phenology, degradation of permafrost, snow depth and covered extent, decomposition of soil organic matter, and subsequently, soil carbon emission to the atmosphere. However, there is fully not understood on the effect of crustose lichen on soil CO2 emission to the atmosphere. Although the spores of lichen are spread by wind and animals, the crustose lichen is infected to the only sphagnum moss widely distributed in the Arctic, and is terminally killed the moss. Here, we report the research findings on the soil CO2 efflux-measurement with forced diffusion (FD) chamber system that is continuously monitored in sphagnum moss regime of west Alaska for the growing season of 2016. The environmental parameters (e.g., soil temperature and moisture) were measured at intact and infected sphagnum moss regime. The FD chamber is measured at an interval of 10-min and 30-min, which is not significant difference between both intervals (R2 = 0.94; n = 1360; RMSE = 0.043; p sphagnum moss, and 0.27(0.47), 0.45(0.17), 0.50(0.22), and 0.31(0.49) in intact sphagnum moss, respectively. This finding demonstrates that 1) soil CO2 in infected sphagnum moss is one of atmospheric CO2 source in June and July, and 2) soil CO2 efflux is not significant difference between both regimes for August and September of 2016.

  8. Estudios florísticos y ecológicos sobre las algas de agua dulce de turberas de Tierra del Fuego

    OpenAIRE

    Mataloni, María Gabriela

    1994-01-01

    En esta Tesis Doctoral se realizan diversas investigaciones florísticas y ecológicas sobre las algas de turberas de Sphagnum de la provincia de Tierra Fuego. Para ello se condijeron básicamente dos trabajos. en la primera parte se estudiaron ocho ojos de agua pertenecientes a siete turberas ubicadas en el sur de Tierra del Fuego. En cada una de ellas se muestrearon tanto el fitoplancton del agua libre como las algas que viven asociadas a Sphagnum a lo largo de un gradiente ambiental caracteri...

  9. Effect of fire on phosphorus forms in Sphagnum moss and peat soils of ombrotrophic bogs.

    Science.gov (United States)

    Wang, Guoping; Yu, Xiaofei; Bao, Kunshan; Xing, Wei; Gao, Chuanyu; Lin, Qianxin; Lu, Xianguo

    2015-01-01

    The effect of burning Sphagnum moss and peat on phosphorus forms was studied with controlled combustion in the laboratory. Two fire treatments, a light fire (250 °C) and a severe fire (600 °C), were performed in a muffle furnace with 1-h residence time to simulate the effects of different forest fire conditions. The results showed that fire burning Sphagnum moss and peat soils resulted in losses of organic phosphorus (Po), while inorganic phosphorus (Pi) concentrations increased. Burning significantly changed detailed phosphorus composition and availability, with severe fires destroying over 90% of organic phosphorus and increasing the availability of inorganic P by more than twofold. Our study suggest that, while decomposition processes in ombrotrophic bogs occur very slowly, rapid changes in the form and availability of phosphorus in vegetation and litter may occur as the result of forest fires on peat soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. [Effect of mechanical grinding of Sphagnum on the structure and physiological state of bacterial communities].

    Science.gov (United States)

    Dobrovol'skaya, T G; Golovchenko, A V; Yakushev, A V; Manucharova, N A; Yurchenko, E N

    2014-01-01

    The microcosm method was used to demonstrate an increase in bacterial numbers and drastic changes in the taxonomic structure of saprotrophic bacteria as a result of mechanical grinding of Sphagnum moss. Ekkrisotrophic agrobacteria predominant in untreated moss were replaced by hydrolytic bacteria. Molecular biological approaches revealed such specific hydrolytic bacteria as Janthinobacterium agaricum and Streptomyces purpurascens among the dominant taxa. The application of kinetic technique for determination of the physiological state of bacteria in situ revealed higher functional diversity of hydrolytic bacteria in ground moss than in untreated samples. A considerable decrease of the C/N ratio in ground samples of living Sphagnum incubated using the microcosm technique indicated decomposition of this substrate.

  11. The effect of elevated CO{sub 2} concentration on photosynthesis of Sphagnum fuscum

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J; Silvola, J [Joensuu Univ. (Finland). Dept. of Biology

    1997-12-31

    The objectives of the research were to measure photosynthesis of Sphagnum fuscum in long term exposure to four CO{sub 2} levels at semi-natural conditions, to find out if there is an acclimation of net photosynthesis into prevailing CO{sub 2} concentrations and to measure the moisture dependent net photosynthesis at various CO{sub 2} concentrations of samples grown at different CO{sub 2} concentrations

  12. The effect of elevated CO{sub 2} concentration on photosynthesis of Sphagnum fuscum

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J.; Silvola, J. [Joensuu Univ. (Finland). Dept. of Biology

    1996-12-31

    The objectives of the research were to measure photosynthesis of Sphagnum fuscum in long term exposure to four CO{sub 2} levels at semi-natural conditions, to find out if there is an acclimation of net photosynthesis into prevailing CO{sub 2} concentrations and to measure the moisture dependent net photosynthesis at various CO{sub 2} concentrations of samples grown at different CO{sub 2} concentrations

  13. Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

    International Nuclear Information System (INIS)

    Niemi, Riikka; Holopainen, Toini; Martikainen, Pertti J.; Silvola, Jouko

    2002-01-01

    Microcosms of a boreal peatland originating from an oligotrophic fen in Eastern Finland were fumigated under four ozone concentrations (0, 50, 100 and 150 ppb O 3 ) in laboratory growth chambers during two separate experiments (autumn and summer) for 4 and 6 weeks, respectively. Ozone effects on Sphagnum mosses and the fluxes of carbon dioxide and methane were evaluated. In both experiments, the three Sphagnum species studied showed only a few significant responses to ozone. In the autumn experiment, membrane permeability of S. angustifolium, measured as conductivity and magnesium leakage, was significantly higher under ozone fumigation (P=0.005 and 2 exchange during the 6-week-long summer experiment, but dark ecosystem respiration was transiently increased by ozone concentration of 100 ppb after 14 days of exposure (P<0.05). Fumigation with 100 ppb of ozone, however, more than doubled (P<0.05) methane emission from the peatland monoliths. Our results suggest that increasing tropospheric ozone concentration may cause substantial changes in the carbon gas cycling of boreal peatlands, even though these changes are not closely associated with the changes in Sphagnum vegetation

  14. Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands.

    Science.gov (United States)

    Granath, Gustaf; Limpens, Juul; Posch, Maximilian; Mücher, Sander; de Vries, Wim

    2014-04-01

    To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900-2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Radiocarbon dating of Sphagnum cellulose from Mohos peat bog, East Carpathians

    Science.gov (United States)

    Hubay, Katalin; Braun, Mihály; Harangi, Sándor; Palcsu, László; Túri, Marianna; Rinyu, László; Molnár, Mihály

    2015-04-01

    This work focuses on building a high-resolution age-depth model for quantitative paleoclimate study from the Mohos peat bog, East Carpathians. Peats are important archives for Quaternary science, because they preserve environmental changes. To study the chronology of peat profiles the key is in the precise coring and reliable dating. However, many studies dealing with coring and radiocarbon dating of peat deposits they often shown problems with the proper methods and material. With our novel coring technique we reached undisturbed and uncompressed peat cores from the Mohos bog. A 10 meter deep peat profile was drilled in 2012 using a modified technique of a piston corer. The core presents a continuous peat profile from the last 11.500 cal. yr BP. The chronology was based on AMS radiocarbon analyses of the separated Sphagnum samples from different depths of the profile. The peat samples were wet sieved (40-280 μm) to avoid contamination by rootlets. Dry Sphagnum samples for AMS dating were prepared using the classical acid-base-acid (ABA) method completed with an oxidative bleaching step to get clean cellulose. Sphagnum cellulose samples were converted to CO2 and later graphite and measured by EnvironMICADAS accelerator mass spectrometry (AMS) in Hertelendi Laboratory (Debrecen, Hungary). Fine peat accumulation rate changes (sections with lowest accumulation values) were observed along the profile. Based on the chronology in further studies we want to focus special intervals to investigate environmental changes in the Holocene. Key words: peat, radiocarbon, cellulose

  16. Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs.

    Science.gov (United States)

    Fisher; Graham; Graham

    1998-11-01

    Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996. Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone. Significant differences in both bacterial populations and water chemistry were observed between sites. pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC. Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake. Bacterial abundance also increased across sites of increasing DOC concentration and declining pH. Bacterial activities (rates of [3H]leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites. Results using these measures generally supported the trends observed in abundance, although high rates of [3H]leucine incorporation were recorded in the moat at one of the bogs. Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments.

  17. Sphagnum mosses as a microhabitat for invertebrates in acidified lakes and the colour adaptation and substrate preference in Leucorrhinia dubia (Odonata, Anisoptera)

    Energy Technology Data Exchange (ETDEWEB)

    Henrikson, B.-I. (Dept. of Zoology, Sect. of Animal Ecology, Univ. of Goeteborg, Goeteborg (Sweden))

    1993-01-01

    The increase of peat mosses, Sphagnum spp., in acidified lakes leads to a changed microhabitat structure for benthic invertebrates. The importance of this change was investigated for some benthic invertebrates. Comparisons between quantitative samples of Sphagnum and debris within the acidified Lake Stora Haestevatten, in the Lake Gaardsjoen catchment of SW Sweden, showed significantly higher abundances of Chironomidae, Ceratopogonidae, Odonata, Trichoptera, Cladocera and Argyroneta aquatica (Araneae) in Sphagnum. For chironomidae and Cladocera the differences were tenfold. Special reference was made to the libellulid Leucorrhinia dubia which is common in acid lakes. In a laboratory test, late instar larvae of L. dubia were shown to change colour to correspond to the brown and green colour of Sphagnum. This result was completed with a field test where larvae of L. dubia were significantly more common in Sphagnum of the same colour as the larvae. The ability to change colour may have an adaptive value when coexisting with visual predators. Small larvae were more prevalent in Sphagnum and they also showed a preference for this substrate in the laboratory test. Laboratory tests showed mediumsized larvae preferred Sphagnum. Larvae of L. dubia were more successful as predators on Asellus aquaticus in Sphagnum substrate than in debris in the laboratory test. Laboratory predation tests with notonecta glauca, Corixa dentipes, Acilius sulcatus, Hyphydrus ovatus and L. dubia showed that they could all feed on larvae of L. dubia. The complex habitat structure of Sphagnum is probably the reason for the high abundance of invertebrates since it may serve as both shelter against predation and as foraging sites. it is probably important as a key habitat for young instars of, for example, L. dubia. In lakes with large Sphagnum mats, L. dubia can coexist with fish. The expansion of Sphagnum due to acidification will probably benefit many acid-tolerant invertebrate species. (au)

  18. Light-stress avoidance mechanisms in a Sphagnum-dominated wet coastal Arctic tundra ecosystem in Alaska.

    Science.gov (United States)

    Zona, D; Oechel, Walter C; Richards, James H; Hastings, Steven; Kopetz, Irene; Ikawa, Hiroki; Oberbauer, Steven

    2011-03-01

    The Arctic experiences a high-radiation environment in the summer with 24-hour daylight for more than two months. Damage to plants and ecosystem metabolism can be muted by overcast conditions common in much of the Arctic. However, with climate change, extreme dry years and clearer skies could lead to the risk of increased photoxidation and photoinhibition in Arctic primary producers. Mosses, which often exceed the NPP of vascular plants in Arctic areas, are often understudied. As a result, the effect of specific environmental factors, including light, on these growth forms is poorly understood. Here, we investigated net ecosystem exchange (NEE) at the ecosystem scale, net Sphagnum CO2 exchange (NSE), and photoinhibition to better understand the impact of light on carbon exchange from a moss-dominated coastal tundra ecosystem during the summer season 2006. Sphagnum photosynthesis showed photoinhibition early in the season coupled with low ecosystem NEE. However, later in the season, Sphagnum maintained a significant CO2 uptake, probably for the development of subsurface moss layers protected from strong radiation. We suggest that the compact canopy structure of Sphagnum reduces light penetration to the subsurface layers of the moss mat and thereby protects the active photosynthetic tissues from damage. This stress avoidance mechanism allowed Sphagnum to constitute a significant percentage (up to 60%) of the ecosystem net daytime CO2 uptake at the end of the growing season despite the high levels of radiation experienced.

  19. Elevated atmospheric CO2 and increased nitrogen deposition : effects on C and N metabolism and growth of the peat moss Sphagnum recurvum P. Beauv. var. mucronatum (Russ.) Warnst

    NARCIS (Netherlands)

    van der Heijden, E; Verbeek, S.K.; Kuiper, P.J C

    Sphagnum bogs play an important role when considering the impacts of global change on global carbon and nitrogen cycles. Sphagnum recurvum P. Beauv. var. mucronatum (Russ.) was grown at 360 (ambient) and 700 mu L L-1 (elevated) atmospheric [CO2] in combination with different nitrogen deposition

  20. Environmental controls on δ13C variations of Sphagnum derived n-alkanes in the Dajiuhu peatland, central China

    Science.gov (United States)

    Huang, X.; Xue, J.; Wang, X.; WANG, H.; Meyers, P. A.; Qin, Y.; Gong, L.; Ding, W.

    2012-12-01

    Northern peatlands are one of the very important atmospheric carbon sinks and represent about 30% of the global soil organic carbon (Gorham, 1991). In peatland conditions, high water levels and consequent anoxia make them an important source of methane. A recent study revealed that methanotrophic bacteria growing on stems or in hyaline cells of Sphagnum can provide methane derived carbon for photosynthesis (Raghoebarsing et al., 2005). This interaction has been found to be globally prevalent in peat-moss ecosystems and can contribute up to 30% of carbon for Sphagnum photosynthesis (Kip et al., 2010). Due to the uptake of 13C-depleted methane-derived CO2 and the sensitivity of methane oxidizing bacteria to the surface wetness, the carbon isotopic signatures of Sphagnum derived lipids have the potential to be used as a proxy for the surface wetness in peatlands and hence as paleoclimate archives (Nichols et al., 2009). In this study, we report the δ13C variations of the Sphagnum derived n-C23 alkane in both fresh Sphagnum and surface peat samples in the Dajiuhu peatland, a small fen located in the Shennongjia forestry region, Hubei province, central China. The δ13C23 values of Sphagnum show a negative correlation with the water level, supporting the idea that that the carbon isotope fractionation of Sphagnum is mainly manifested by the diffusion resistance of CO2 in hyaline cells of Sphagnum. However, δ13C23 values of surface peats collected in Sphagnum dominated ecosystems display a positive relation with the water level when the water level is less than 30 cm. Such an inconsistency probably results from the higher potential for methane-oxidizing activity in the lower parts of Sphagnum in fen meadows. When the water level is higher than 30 cm, the influence of symbiotic methanotrophic bacteria on Sphagnum derived n-C23 alkane is weak or nearly absent. These findings provide direct evidence to support the hypothesis that the carbon isotopic signatures of Sphagnum

  1. The effect of temperature on growth and competition between Sphagnum species.

    Science.gov (United States)

    Breeuwer, Angela; Heijmans, Monique M P D; Robroek, Bjorn J M; Berendse, Frank

    2008-05-01

    Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4 degrees C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species.

  2. Effect of N deposition on tree amino acid concentrations in two Sphagnum species

    Energy Technology Data Exchange (ETDEWEB)

    Karsisto, M; Kitunen, V [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1997-12-31

    Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

  3. Effects of shading on relative competitive advantage of three species of Sphagnum

    Directory of Open Access Journals (Sweden)

    J.Z. Ma

    2015-06-01

    Full Text Available (1 Sphagnum is an important genus of bryophytes holding 10–15 % of the terrestrial carbon stock. With climate change a drier surface may increase the abundance of vascular plants on peatlands, so shading of Sphagnum may increase. Here we describe growth cabinet experiments to reveal the effects of shading on interactions among mixtures of three species: S. capillifolium, S. palustre (hummock species, and S. fallax (a hollow species. We measured the six traits: growth in length, growth as increase in dry mass, side-shoot production, nitrogen and carbon proportion of the capitulum dry mass, and C:N ratio in the capitulum. (2 Shading had no effect on biomass production or side-shoot production but increased height increment in all three species. It also increased the C and N proportions of total dry mass but decreased C:N ratio in the capitula. (3 Neighbours of a different species reduced biomass and side-shoot production in the two hummock species but had no effect on the hollow species. (4 All three species showed interaction between shading and neighbour in two or more plant traits. S. fallax showed competitive advantage over S. palustre in no-shading treatments and over S. capillifolium in moderate shading treatments. In addition, under deep shading, S. fallax showed a competitive advantage over both hummock species. A clear competitive hierarchy S. fallax>S. capillifolium>S. palustre emerged which was consistent with the hierarchy of side-shoot production. (5 The results suggest that all the species appear to tolerate deep shade (for a few months at least. In a shaded environment, especially under deeply shaded conditions, S. fallax retains its dominance in hollow habitats (if water availability is guaranteed by virtue of its advantage in side-shoot production. (6 If shading increases then the abundance of different Sphagnum species is likely to change.

  4. Spatial Genetic Structure of the Abundant and Widespread Peatmoss Sphagnum magellanicum Brid.

    Directory of Open Access Journals (Sweden)

    Magni Olsen Kyrkjeeide

    Full Text Available Spore-producing organisms have small dispersal units enabling them to become widespread across continents. However, barriers to gene flow and cryptic speciation may exist. The common, haploid peatmoss Sphagnum magellanicum occurs in both the Northern and Southern hemisphere, and is commonly used as a model in studies of peatland ecology and peatmoss physiology. Even though it will likely act as a rich source in functional genomics studies in years to come, surprisingly little is known about levels of genetic variability and structuring in this species. Here, we assess for the first time how genetic variation in S. magellanicum is spatially structured across its full distribution range (Northern Hemisphere and South America. The morphologically similar species S. alaskense was included for comparison. In total, 195 plants were genotyped at 15 microsatellite loci. Sequences from two plastid loci (trnG and trnL were obtained from 30 samples. Our results show that S. alaskense and almost all plants of S. magellanicum in the northern Pacific area are diploids and share the same gene pool. Haploid plants occur in South America, Europe, eastern North America, western North America, and southern Asia, and five genetically differentiated groups with different distribution ranges were found. Our results indicate that S. magellanicum consists of several distinct genetic groups, seemingly with little or no gene flow among them. Noteworthy, the geographical separation of diploids and haploids is strikingly similar to patterns found within other haploid Sphagnum species spanning the Northern Hemisphere. Our results confirm a genetic division between the Beringian and the Atlantic that seems to be a general pattern in Sphagnum taxa. The pattern of strong genetic population structuring throughout the distribution range of morphologically similar plants need to be considered in future functional genomic studies of S. magellanicum.

  5. Photosynthetic performance in Sphagnum transplanted along a latitudinal nitrogen deposition gradient.

    Science.gov (United States)

    Granath, Gustaf; Strengbom, Joachim; Breeuwer, Angela; Heijmans, Monique M P D; Berendse, Frank; Rydin, Håkan

    2009-04-01

    Increased N deposition in Europe has affected mire ecosystems. However, knowledge on the physiological responses is poor. We measured photosynthetic responses to increasing N deposition in two peatmoss species (Sphagnum balticum and Sphagnum fuscum) from a 3-year, north-south transplant experiment in northern Europe, covering a latitudinal N deposition gradient ranging from 0.28 g N m(-2) year(-1) in the north, to 1.49 g N m(-2) year(-1) in the south. The maximum photosynthetic rate (NP(max)) increased southwards, and was mainly explained by tissue N concentration, secondly by allocation of N to the photosynthesis, and to a lesser degree by modified photosystem II activity (variable fluorescence/maximum fluorescence yield). Although climatic factors may have contributed, these results were most likely attributable to an increase in N deposition southwards. For S. fuscum, photosynthetic rate continued to increase up to a deposition level of 1.49 g N m(-2) year(-1), but for S. balticum it seemed to level out at 1.14 g N m(-2) year(-1). The results for S. balticum suggested that transplants from different origin (with low or intermediate N deposition) respond differently to high N deposition. This indicates that Sphagnum species may be able to adapt or physiologically adjust to high N deposition. Our results also suggest that S. balticum might be more sensitive to N deposition than S. fuscum. Surprisingly, NP(max) was not (S. balticum), or only weakly (S. fuscum) correlated with biomass production, indicating that production is to a great extent is governed by factors other than the photosynthetic capacity.

  6. Unsaturated hydraulic properties of Sphagnum moss and peat reveal trimodal pore-size distributions

    Science.gov (United States)

    Weber, Tobias K. D.; Iden, Sascha C.; Durner, Wolfgang

    2017-01-01

    In ombrotrophic peatlands, the moisture content of the vadose zone (acrotelm) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Whether peatlands act as sinks or sources of atmospheric carbon thus relies on variably saturated flow processes. The Richards equation is the standard model for water flow in soils, but it is not clear whether it can be applied to simulate water flow in live Sphagnum moss. Transient laboratory evaporation experiments were conducted to observe evaporative water fluxes in the acrotelm, containing living Sphagnum moss, and a deeper layer containing decomposed moss peat. The experimental data were evaluated by inverse modeling using the Richards equation as process model for variably-saturated flow. It was tested whether water fluxes and time series of measured pressure heads during evaporation could be simulated. The results showed that the measurements could be matched very well providing the hydraulic properties are represented by a suitable model. For this, a trimodal parametrization of the underlying pore-size distribution was necessary which reflects three distinct pore systems of the Sphagnum constituted by inter-, intra-, and inner-plant water. While the traditional van Genuchten-Mualem model led to great discrepancies, the physically more comprehensive Peters-Durner-Iden model which accounts for capillary and noncapillary flow, led to a more consistent description of the observations. We conclude that the Richards equation is a valid process description for variably saturated moisture fluxes over a wide pressure range in peatlands supporting the conceptualization of the live moss as part of the vadose zone.

  7. Spatial Genetic Structure of the Abundant and Widespread Peatmoss Sphagnum magellanicum Brid.

    Science.gov (United States)

    Kyrkjeeide, Magni Olsen; Hassel, Kristian; Flatberg, Kjell Ivar; Shaw, A Jonathan; Yousefi, Narjes; Stenøien, Hans K

    2016-01-01

    Spore-producing organisms have small dispersal units enabling them to become widespread across continents. However, barriers to gene flow and cryptic speciation may exist. The common, haploid peatmoss Sphagnum magellanicum occurs in both the Northern and Southern hemisphere, and is commonly used as a model in studies of peatland ecology and peatmoss physiology. Even though it will likely act as a rich source in functional genomics studies in years to come, surprisingly little is known about levels of genetic variability and structuring in this species. Here, we assess for the first time how genetic variation in S. magellanicum is spatially structured across its full distribution range (Northern Hemisphere and South America). The morphologically similar species S. alaskense was included for comparison. In total, 195 plants were genotyped at 15 microsatellite loci. Sequences from two plastid loci (trnG and trnL) were obtained from 30 samples. Our results show that S. alaskense and almost all plants of S. magellanicum in the northern Pacific area are diploids and share the same gene pool. Haploid plants occur in South America, Europe, eastern North America, western North America, and southern Asia, and five genetically differentiated groups with different distribution ranges were found. Our results indicate that S. magellanicum consists of several distinct genetic groups, seemingly with little or no gene flow among them. Noteworthy, the geographical separation of diploids and haploids is strikingly similar to patterns found within other haploid Sphagnum species spanning the Northern Hemisphere. Our results confirm a genetic division between the Beringian and the Atlantic that seems to be a general pattern in Sphagnum taxa. The pattern of strong genetic population structuring throughout the distribution range of morphologically similar plants need to be considered in future functional genomic studies of S. magellanicum.

  8. The effect of temperature on growth and competition between Sphagnum species

    Science.gov (United States)

    Heijmans, Monique M. P. D.; Robroek, Bjorn J. M.; Berendse, Frank

    2008-01-01

    Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4°C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species. PMID:18283501

  9. Effect of N deposition on tree amino acid concentrations in two Sphagnum species

    Energy Technology Data Exchange (ETDEWEB)

    Karsisto, M.; Kitunen, V. [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

  10. Plant diversity affects GHG fluxes in an ecological engineering experiment in a disturbed Sphagnum peatland (La Guette, France)

    Science.gov (United States)

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

    2017-04-01

    Many Sphagnum peatlands are experiencing vegetation change caused mainly by hydrological disturbances. In the context of these direct and indirect modifications, greenhouse gases (GHG) fluxes are affected by peat oxygenation, changes in litter composition (and thus decomposition) and rhizospheric processes (such as root exudates). This could lead a C sink system to switch to a source. To restore peatland functioning, ecological engineering works can be undertaken. Our study site, La Guette peatland (central France) is invaded by Molinia caerulea because a drain at the output decreased the water table depth. It was shown that it functioned as a source of C. In 2014, hydrological works were undertaken: 8 dams were installed, ditches were dug perpendicular to the water flow and back-filled with a mixture of shales and bentonite. In addition, a biodiversity experiment with 2 identical experimental stations was implemented: "downstream", close to the hydraulic works (relatively wet), "upstream", (relatively dry), with types of 3 vegetation plot (2m x 2m, n=4): 1) "control": intact vegetation (Molinia caerulea, Erica tetralix), 2) "bare" peat: vegetation and 5cm of peat were removed, 3) "Sphagnum": bare peat+Sphagnum. Our study aims to assess the effect of the vegetation treatment on the GHG fluxes. CO2 (ecosystem respiration or ER, Gross Primary Production or GPP, and Net Ecosystem Exchange) and CH4 fluxes (manual accumulation chamber), air and soil temperature, water table level, soil moisture were measured. After 18 months, half of the surface of "bare" and "Sphagnum" plots were covered by vegetation (Eriophorum angustifolium, Rynchospora alba, Trichophorum cespitosum). With time, as succession unfolds in these 2 types of station, ER and GPP increased. The sensitivity of ER to temperature increased sharply in "bare" and "Sphagnum" plots with years and became higher than the sensitivity in "control" plots. GPP increased with the total vegetation percentage cover

  11. Mechanochemical treatment of amorphous carbon from brown sphagnum moss for the preparation of carbon nanotubes

    International Nuclear Information System (INIS)

    Onishchenko, D.V.

    2013-01-01

    Under consideration is the mechanism of multiwalled nanotubes formation during mechanical activation of amorphous carbon synthesized by pyrolysis of sphagnum moss. The formation of nanotubes has been shown to take place in the array of carbon particles. A complex study of the sorption characteristics of carbon nanotubes has been carried out. The dependence of the sorption capacity of carbon nanotubes on their storage time, as well as the effect of the process parameters of nanotubes formation on their ability for oxidative modification, is represented. (authors)

  12. The response of vegetation structure to active warming and precipitation reduction of the Sphagnum peatland

    Science.gov (United States)

    Łuców, Dominika; Basińska, Anna; Chojnicki, Bogdan; Gąbka, Maciej; Józefczyk, Damian; Juszczak, Radosław; Leśny, Jacek; Olejnik, Janusz; Reczuga, Monika; Samson, Mateusz; Silvennoinen, Hanna; Stróżecki, Marcin; Urbaniak, Marek; Zielińska, Małgorzata; Lamentowicz, Mariusz

    2017-04-01

    The recent climate change (e.g. increased temperature and decreased precipitation) is expected to affect biodiversity and vegetation structure of the European peatlands, as well as carbon fluxes. Our experimental study carried out in Western Poland, tests the hypothesis that the increased temperature, in particular in combination with rainfall reduction affects vegetation structure of the Sphagnum peatland, through changes in moss and vascular plants abundance. The innovative climate manipulation system was installed on the Rzecin peatland in 2014. The field site consists of four blocks: "drought" "warming and drought" "warming" and "control". The air and peat temperatures were increased in 2015 and 2016 by about 0.2 oC and 1.0 oC, respectively, using infrared radiators. Precipitation was reduced by automatic curtain operated only during the nights by about 37 % in both years. Data resulting from the analyses of digital pictures as well as Point Intercept method were used to identify changes in vegetation structure as a response to warming and drought. We observed increase in abundance of vascular plant and decrease in abundance of mosses during the very dry 2015 vegetation season. It appeared that Carex spp. (C. limosa and C. rostrata) abundance responded positively to warming, while Sphagnum spp. (S. angustifolium and S. teres) responded negatively. The "warming" block was characterized by an increase in abundance of Carex spp. by 8.3 % to 16.7 % and decreased abundance of Sphagnum spp. from 25 % to 19.4 %, whereas in the block of "warming and drought" 11.4 % to by 18.3 and 38 % to 26.9 %, respectively in the August 2015. However, we observed decrease in Sphagnum spp. abundance in the treatment with rainfall reduction in wetter 2016, and their increase in the control. Our results show how considerable changes in vegetation structure can be expected under the stress of warming and modified rainfall conditions, even after a short-term manipulation. However, it is

  13. Effects of volume change on the unsaturated hydraulic conductivity of Sphagnum moss

    Science.gov (United States)

    Golubev, V.; Whittington, P.

    2018-04-01

    Due to the non-vascular nature of Sphagnum mosses, the capitula (growing surface) of the moss must rely solely on capillary action to receive water from beneath. Moss subsides and swells in accordance with water table levels, an effect called "mire-breathing", which has been thought to be a self-preservation mechanism, although no systematic studies have been done to demonstrate exactly how volume change affects hydrophysical properties of moss. In this study, the unsaturated hydraulic conductivity (Kunsat) and water content of two different species of Sphagnum moss were measured at different compression rates, up to the maximum of 77%. The findings show that the Kunsat increases by up to an order of magnitude (10×) with compression up to a certain bulk density of the moss, after which higher levels of compression result in lowered unsaturated hydraulic conductivity. This was coupled with an increase in soil water retention with increased compression. The increase of the Kunsat with compression suggests that the mire-breathing effect should be considered a self-preservation mechanism to provide sufficient amount of water to growing moss in times of low water availability.

  14. Seasonal changes in Sphagnum peatland testate amoeba communities along a hydrological gradient.

    Science.gov (United States)

    Marcisz, Katarzyna; Lamentowicz, Lukasz; Słowińska, Sandra; Słowiński, Michał; Muszak, Witold; Lamentowicz, Mariusz

    2014-10-01

    Testate amoebae are an abundant and functionally important group of protists in peatlands, but little is known about the seasonal patterns of their communities. We investigated the relationships between testate amoeba diversity and community structure and water table depth and light conditions (shading vs. insolation) in a Sphagnum peatland in Northern Poland (Linje mire) in spring and summer 2010. We monitored the water table at five sites across the peatland and collected Sphagnum samples in lawn and hummock micro-sites around each piezometer, in spring (3 May) and mid-summer (6 August) 2010. Water table differed significantly between micro-sites and seasons (Kruskal-Wallis test, p=0.001). The community structure of testate amoebae differed significantly between spring and summer in both hummock and lawn micro-sites. We recorded a small, but significant drop in Shannon diversity, between spring and summer (1.76 vs. 1.72). Strongest correlations were found between testate amoeba communities and water table lowering and light conditions. The relative abundance of mixotrophic species Hyalosphenia papilio, Archerella flavum and of Euglypha ciliata was higher in the summer. Copyright © 2014 Elsevier GmbH. All rights reserved.

  15. Sphagnum peatland development at their southern climatic range in West Siberia: trends and peat accumulation patterns

    International Nuclear Information System (INIS)

    Peregon, Anna; Uchida, Masao; Shibata, Yasuyuki

    2007-01-01

    A region of western Siberia is vulnerable to the predicted climatic change which may induce an important modification to the carbon balance in wetland ecosystems. This study focuses on the evaluation of both the long-term and contemporary trends of peat (carbon) accumulation and its patterns at the southern climatic range of Sphagnum peatlands in western Siberia. Visible and physical features of peat and detailed reconstructions of successional change (or sediment stratigraphies) were analysed at two types of forest-peatland ecotones, which are situated close to each other but differ by topography and composition of their plant communities. Our results suggest that Siberian peatlands exhibit a general trend towards being a carbon sink rather than a source even at or near the southern limit of their distribution. Furthermore, two types of peat accumulation were detected in the study area, namely persistent and intermittent. As opposed to persistent peat accumulation, the intermittent one is characterized by the recurrent degradation of the upper peat layers at the marginal parts of raised bogs. Persistent peat accumulation is the case for the majority of Sphagnum peatlands under current climatic conditions. It might be assumed that more peat will accumulate under the 'increased precipitation' scenarios of global warming, although intermittent peat accumulation could result in the eventual drying that may change peatlands from carbon sinks to carbon sources

  16. North American origin and recent European establishments of the amphi-Atlantic peat moss Sphagnum angermanicum.

    Science.gov (United States)

    Stenøien, Hans K; Shaw, A Jonathan; Shaw, Blanka; Hassel, Kristian; Gunnarsson, Urban

    2011-04-01

    Genetic and morphological similarity between populations separated by large distances may be caused by frequent long-distance dispersal or retained ancestral polymorphism. The frequent lack of differentiation between disjunct conspecific moss populations on different continents has traditionally been explained by the latter model, and has been cited as evidence that many or most moss species are extremely ancient and slowly diverging. We have studied intercontinental differentiation in the amphi-Atlantic peat moss Sphagnum angermanicum using 23 microsatellite markers. Two major genetic clusters are found, both of which occur throughout the distributional range. Patterns of genetic structuring and overall migration patterns suggest that the species probably originated in North America, and seems to have been established twice in Northern Europe during the past 40,000 years. We conclude that similarity between S. angermanicum populations on different continents is not the result of ancient vicariance and subsequent stasis. Rather, the observed pattern can be explained by multiple long-distance dispersal over limited evolutionary time. The genetic similarity can also partly be explained by incomplete lineage sorting, but this appears to be caused by the short time since separation. Our study adds to a growing body of evidence suggesting that Sphagnum, constituting a significant part of northern hemisphere biodiversity, may be more evolutionary dynamic than previously assumed. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

  17. Effect of light Sphagnum peat on odour formation in the early stages of biowaste composting.

    Science.gov (United States)

    Kurola, Jukka M; Arnold, Mona; Kontro, Merja H; Talves, Matti; Romantschuk, Martin

    2010-05-01

    In the present study, we investigated the effects of two bulking materials, Sphagnum peat and pine wood chips, on the early stages of biowaste composting in two pilot-scale processes. Emphasis was placed on studying the formation conditions of malodorous compost gases in the initial phases of the processes. The results showed that gas emission leaving an open windrow and a closed drum composting system contained elevated concentrations of fermentative microbial metabolites when acid Sphagnum peat (pH 3.2) was used as a bulking material. Moreover, the gas emission of the peat amended drum composter contained a high concentration of odour (up to 450,000oum(-3) of air). The highest odour values in the outlet gas of peat amended composts coincided with the elevated concentrations of volatile organic compounds such as acetoin and buthanedion. We conclude that the acidifying qualities of composting substrates or bulking material may intensify odour emission from biowaste composts and prolong the early stages of the composting process. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  18. The use of Sphagnum cellulose oxygen isotope ratios in ombrotrophic peatlands as a proxy for paleoclimate.

    Science.gov (United States)

    Taylor, M.; Pendall, E.; Jackson, S.; Booth, R. K.; Nichols, J. E.; Huang, Y.

    2006-12-01

    Developing proxies for discerning paleoclimate that are independent of the pollen record can provide insight into various aspects of climate variability and improve confidence in the interpretation of climate-vegetation interactions. To date, proxies including plant macrofossils, humification indices, testate amoebae, and ratios of n-alkane abundances have been used to infer past climate variability from temperate ombrotrophic peatlands in upper Midwestern North America. These proxies are used to infer past changes in surface-moisture conditions, which in ombrotrophic peatlands is primarily a function of precipitation and temperature. This study investigates the potential uses of stable oxygen isotopes to complement hydrologic proxies. δ18O of surface water and Sphagnum moss cellulose from bogs throughout North America indicates a correlation between average growing season temperatures and δ18O-values. The existence of a modern temperature signal in moss cellulose suggests that δ18O-derived records will not only complement paleohydrological records, but also help assess relative changes in precipitation and temperature. Humification and testate amoebae data from two cores taken from Minden and Irwin Smith Bogs in central and northeastern Michigan have recorded several extreme drought events during the Holocene, including one at 1000 YBP. Comparison of δ18O-values of picked Sphagnum remains to down-core humification and testate amoebae data suggest good temporal correspondence, with the δ18O-values around 1000 YBP indicating a warmer growing season.

  19. Minor effects of long-term ozone exposure on boreal peatland species Eriophorum vaginatum and Sphagnum papillosum

    DEFF Research Database (Denmark)

    Mörsky, SK; Haapala, JK; Rinnan, Riikka

    2011-01-01

    The effects of long-term ozone fumigation on two common peatland plant species, a sedge Eriophorum vaginatum L. and a moss Sphagnum papillosum Lindb., were studied applying peatland microcosms. The peat cores with intact vegetation were cored from an oligotrophic pine fen and partially embedded...

  20. Fractionation of hydrogen, oxygen and carbon isotopes in n-alkanes and cellulose of three Sphagnum species

    NARCIS (Netherlands)

    Brader, A.V.; Winden, J.F.; Bohncke, S.J.P.; Beets, C.J.; Reichart, G.-J.; De Leeuw, J.W.

    2010-01-01

    Compound-specific isotope measurements of organic compounds are increasingly important in palaeoclimate reconstruction. Searching for more accurate peat-based palaeoenvironmental proxies, compound-specific fractionation of stable C, H and O isotopes of organic compounds synthesized by Sphagnum were

  1. Sphagnum-mediated successional pattern in the mixed mire in the Muránska planina Mts (Western Carpathians, Slovakia)

    Czech Academy of Sciences Publication Activity Database

    Hájková, P.; Hájek, Michal

    2004-01-01

    Roč. 59, č. 1 (2004), s. 65-74 ISSN 0006-3088 R&D Projects: GA AV ČR KSK6005114; GA ČR GA206/02/0568 Institutional research plan: CEZ:AV0Z6005908 Keywords : Sphagnum ecology * brown mosses * niche breadth Subject RIV: EF - Botanics Impact factor: 0.207, year: 2004

  2. Decreasing concentrations of metals in Sphagnum mosses in ombrotrophic mires of the Sudety mountains (SW Poland) since late 1980s.

    Science.gov (United States)

    Wojtuń, Bronisław; Samecka-Cymerman, Aleksandra; Kolon, Krzysztof; Kempers, Alexander J

    2013-06-01

    In this investigation we focus on the evaluation of changes in metal pollution between 1986 until 2011 by Sphagnum species as bioindicators in 100 km part of the Sudety mountains influenced by the former Black Triangle Region. Concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in various Sphagnum species all from ombrotrophic bogs in the Sudety mountains (SW Poland). The tested hypothesis was that overall improvements in pollution control in the former Black Triangle Region between 1986 until recent reduced the amount of metals deposited and accumulated by these plants. Concentrations of Cd, Cr, Cu, Fe, Pb and Zn in Sphagnum species were very high in 1986 indicating a heavy pollution of the examined bogs in this period, and significantly higher than in samples collected in 2011. The PCCA ordination showed the similar pattern in all bogs. In 2011 concentration of the Co was significantly higher in hollow species and concentration of Mn was significantly higher in those from hummocks. Differences between hollow/hummock sites were more important than species-specific abilities of Sphagnum mosses to accumulate metals. Species from hollows were better bioindicators of Co and those from hummocks were better bioindicators of Mn pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Effect of a temperature gradient on Sphagnum fallax and its associated living microbial communities: a study under controlled conditions.

    Science.gov (United States)

    Jassey, Vincent E J; Gilbert, Daniel; Binet, Philippe; Toussaint, Marie-Laure; Chiapusio, Geneviève

    2011-03-01

    Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.

  4. The sensitivity of Sphagnum to surface layer conditions in a re-wetted bog: a simulation study of water stress

    NARCIS (Netherlands)

    Schouwenaars, J.M.; Gosen, A.M.

    2007-01-01

    The behaviour of the water table in re-wetted bogs varies widely between different locations so that recolonising Sphagnum is vulnerable to water stress, especially when the water table is drawn down in summer. It is important to understand how physical site conditions influence the occurrence of

  5. Competition between Sphagnum magellanicum and Eriophorum angustifolium as affected by raised CO2 and increased N deposition

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Klees, H.; Berendse, F.

    2002-01-01

    The competition between peat mosses (Sphagnum) and vascular plants as affected by raised CO2 and increased N deposition was studied in a glasshouse experiment by exposing peat monoliths with monocultures and mixtures of Sphagnummagellanicum and Eriophorumangustifolium to ambient (350 ppmv) or raised

  6. The effects of water management on the CO2 uptake of Sphagnum moss in a reclaimed peatland

    Directory of Open Access Journals (Sweden)

    C.M. Brown

    2017-07-01

    Full Text Available To harvest Sphagnum on a cyclic basis and rapidly accumulate biomass, active water management is necessary. The goal of this study is to determine the hydrological conditions that will maximise CO2 uptake in Sphagnum farming basins following the moss-layer transfer technique. Plot CO2 uptake doubled from the first growing season to the second, but growth was not uniform across the site. Results indicate that the seasonal oscillations in water table (WT position were more important than actual WT position for estimating Sphagnum ground cover and CO2 uptake when the seasonal WT is shallow (< -25 cm. Plots with higher productivity had a WT range (seasonal maximum – minimum less than 15 cm, a WT position which did not fluctuate more than ± 7.5 cm, and a low WT standard deviation. Each basin was a CO2 source during the second growing season, and seasonal modelled NEE ranged from 107.1 to 266.8 g CO2 m-2. Decomposition from the straw mulch accounted for over half of seasonal respiration, and the site is expected to become a CO2 sink as the straw mulch decomposes and moss cover increases. This study highlights the importance of maintaining stable moisture conditions to increase Sphagnum growth and CO2 sink functions.

  7. Application of sphagnum peat, calcium carbonate and hydrated lime for immobilizing radioactive and hazardous contaminants in the subsurface

    International Nuclear Information System (INIS)

    Longmire, P.A.; Thomson, B.M.; Eller, P.G.; Barr, M.E.

    1991-01-01

    Batch experiments, mineralogical studies, and geochemical modeling were conducted to evaluate the effectiveness of sphagnum peat, calcium carbonate, and hydrated lime in removing dissolved concentrations of As, Mo, NO 3 , and U present in uranium-tailings pore water at Gunnison, Colorado. Amounts of As, Mo, and U removal by sphagnum peat, calcium carbonate, and hydrated lime at 5.0,2.5, and 2.5 wt.%, respectively, were typically above 97%. Nitrate removal ranged between 55 and 80%. Significant contaminant removal was achieved by sphagnum peat alone at pH 3.18. Results from base potentiometric titration and IR spectroscopy investigations suggest that U(VI) binds onto carboxylate and phenolate groups. Addition of 2.5 wt.% hydrated lime to the acidic tailings increased Mo concentrations by a factor of 2 under moderately alkaline conditions (pH 12). During neutralization of tailings-pore water, precipitation of ferric oxyhydroxides may provide additional removal of As, Mo, and U(VI) from solution through adsorption and coprecipitation processes. Sphagnum peat and other forms of solid organic matter effectively remove anthropogenic organic compounds from solution through hydrophobic sorption and partitioning processes

  8. Acidicapsa borealis gen. nov., sp. nov. and Acidicapsa ligni sp. nov., subdivision 1 Acidobacteria from Sphagnum peat and decaying wood

    NARCIS (Netherlands)

    Kulichevskaya, I.S.; Kostina, L.A.; Valášková, V.; Rijpstra, I.C.; Sinninghe Damsté, J.S.; De Boer, W.; Dedysh, S.N.

    2012-01-01

    Two strains of subdivision 1 Acidobacteria, namely the pink-pigmented bacterium KA1T and the colorless isolate WH120T, were obtained from acidic Sphagnum peat and wood under decay by the white-rot fungus Hyploma fasciculare, respectively. Cells of these isolates are Gram-negative, non-motile, short

  9. Singulisphaera rosea sp. nov., a planctomycete from acidic Sphagnum peat, and emended description of the genus Singulisphaera

    NARCIS (Netherlands)

    Kulichevskaya, I.S.; Detkova, E.N.; Bodelier, P.L.E.; Rijpstra, W.I.C.; Sinninghe Damsté, J.S.; Dedysh, S.N.

    2012-01-01

    A novel species, Singulisphaera rosea sp. nov., is proposed for aerobic, pink-pigmented, budding bacterium isolated from an acidic Sphagnum peat bog of northwestern Russia. This bacterium, designated strain S26T, has non-motile, spherical cells that occur singly, in pairs or in short chains and

  10. Phylogenetic or environmental control on the organo-chemical composition of Sphagnum mosses?

    Science.gov (United States)

    Limpens, Juul; Nilsson, Mats

    2014-05-01

    Decomposition of organic material is one of the key processes that determines the size of the soil-feedback to global warming, but it is also a process surrounded with one of the largest uncertainties, making understanding its mechanistic drivers of crucial importance. In organic soils decomposition is closely determined by the organo-chemical composition of the litter entering the soil. But what, in turn drives the organo-chemical composition? Is it an emergent feature of the environment the species producing the litter grow in, or is it an evolutionary trait that can be tracked through the species' phylogeny? We set out to answer this question for one of the most import peat-forming plants on earth: the genus Sphagnum. We sampled 18 Sphagnum species, about equally distributed over 6 sites spanning a wide range of environmental conditions: most species were collected at multiple sites. For all species we characterised the chemical composition, focussing on three functional chemistry groups: (i) mineral elements, (ii) carbohydrate polymers (iii) non-carbohydrate polymers (aromatic and aliphatic compounds) . For each group of compounds we used multivariate statistical techniques to derive the degree of variation explained by environment: (site, position within site) and phylogeny (sections within genus Sphagnum). We found that the variation in mineral element concentrations was mostly explained by environment, with the biggest differences in the concentrations of basic cat-ions calcium and magnesium. In contrast, the variation in carbohydrates was mostly explained by phylogeny, with clear associations between sections and monosaccharides. The monosaccharide rhamnose was associated with species from the Acutifolia section known for their poor degradability, whereas xylose and galactose were closely associated with degradable species from the Cuspidata section. The composition non-carbohydrate polymers took an intermediate position: both environment and phylogeny

  11. Late Holocene palaeohydrological changes in a Sphagnum peat bog from NW Romania based on testate amoebae

    Directory of Open Access Journals (Sweden)

    Andrei-Cosmin Diaconu

    2016-04-01

    Full Text Available This paper investigates the possibility of reconstructing the palaeohydrological changes in an active Sphagnum peat bog from north-western Romania using testate amoebae fauna and organic matter content determined by loss on ignition (LOI. In total 28 taxa of testate amoebae were identified of which 11 were frequent enough to present a remarkable ecological significance. Based on the relative abundance of these taxa nine zones were identified, crossing from very wet to dry climate conditions. The wet periods identified are characterized by taxa like Centropyxis cassis, Amphitrema flavum and Hyalosphenia papilio, while in the dry periods Difflugia pulex and Nebela militaris thrive. We showed that combining qualitative information regarding hydrological preferences with the quantitative percentage data from the fossil record it is possible to obtain information regarding major surface moisture changes from the peat bog surface. Furthermore we identified a link between distribution of testate amoebae assemblages, organic matter variation and minerogenic material.

  12. Mineral content in Sphagnum mosses from ombrotrophic bogs of southwestern Poland: pattern in species and elements

    Directory of Open Access Journals (Sweden)

    Bronisław Wojtuń

    2014-01-01

    Full Text Available Major elements (N, P, K, Ca, Mg, Na, Fe were analyzed in 11 Sphagnum species from ombrotrophic bogs in southwestern Poland. The material included species from wet to dry microsites. The highest levels of elements were recorded for S. lindbergii, whereas S. balticum and S. cuspidatum were poorest in elements. The microhabitat gradient from hummock to hollow species is clearly reflected by decreasing concentrations of Ca and Mg, and increasing concentration of Na. Phosphorus, K and N were much more enriched into moss tissues than the remaining elements. These three nutrients were also accumulated in the upper green parts of mosses, while the concentrations of Na and Fe were higher in the bottom brown parts. There were no differences in Ca and Mg between the green and brown segments.

  13. Cultivable mycobacteria in sphagnum vegetation of moors in South Sweden and coastal Norway.

    Science.gov (United States)

    Kazda, J; Müller, K; Irgens, L M

    1979-04-01

    Intact sphagnum vegetation from moors in south Sweden and coastal areas of west Norway contained cultivable mycobacteria in 32% and 30% of the specimens, respectively. This frequency of specimens is lower than the 50% previously found in the partly altered moors of northwestern Germany, but the Scandinavian moors contained a larger variety of species. On both intact and altered moors M. chelonei and M. sphagni sp. nov. were found, the latter a homologous group of 151 strains. In south Sweden the highest frequency was found in S. balticum, S. recurvum. S. tenellum and S. compactum & molle. (40-65%). In coastal Norway the highest frequency was found in S. rubellum (48%) which offers favourable conditions for the accumulation of solar energy due to the red brown colour in the upper parts. Combined with a high humidity in coastal Norway in summer, this may contribute to the growth of mesophilic mycobacteria. A significant affinity of M. chelonei to S. tenellum was stated.

  14. [Effects of shading on two Sphagnum species growth and their interactions].

    Science.gov (United States)

    Ma, Jin-Ze; Bu, Zhao-Jun; Zheng, Xing-Xing; Li, Shan-Lin; Zeng, Jing; Zhao, Gao-Lin

    2012-02-01

    Taking Sphagnum palustre and S. fallax as test materials, this paper studied their growth and interactions under shading. In monoculture, shading promoted the height growth of S. palustre markedly, but had no effect on the growth of S. fallax and the biomass and branching of S. palustre. In mixed culture, S. fallax suppressed the increase of biomass and branching of S. palustre, while S. palustre had no effects on S. fallax. With the increase of shading stress, the competition of neighbour on S. fallax intensified. When the stress increased further, neighbor effect on S. fallax tended to be positive. However, the effect of neighbour on S. palustre was always competitive and did not change with the increase of shading stress.

  15. Inhibitory effect of Sphagnum palustre extract and its bioactive compounds on aromatase activity

    Directory of Open Access Journals (Sweden)

    Hee Jeong Eom

    2016-09-01

    Full Text Available Sphagnum palustre (a moss has been traditionally used in Korea for the cure of several diseases such as cardiac pain and stroke. In this research, the inhibitory effect of S. palustre on aromatase (cytochrome P450 19, CYP19 activity was studied. [1β-3H] androstenedione was used as a substrate and incubated with S. palustre extract and recombinant human CYP19 in the presence of NADPH. S. palustre extract inhibited aromatase in a concentration-dependent manner (IC50 value: 36.4 ± 8.1 µg/mL. To elucidate the major compounds responsible for the aromatase inhibitory effects of S. palustre extract, nine compounds were isolated from the extract and tested for their inhibition of aromatase activity. Compounds 1, 6, and 7 displayed aromatase inhibition, while the inhibition by the other compounds was negligible.

  16. Net ecosystem exchange in a sedge-sphagnum fen at the South of West Siberia, Russia

    Science.gov (United States)

    Dyukarev, Egor

    2017-04-01

    The model of net ecosystem exchange was used to study the influence of different environmental factors and to calculate daily and growing season carbon budget for minerotrophic fen at South of West Siberia, Russia. Minerotrophic sedge-sphagnum fen occupies the central part of the Bakcharskoe bog. The model uses air and soil temperature, incoming photosynthetically active radiation, and leaf area index as the explanatory factors for gross primary production, heterotrophic and autotrophic respiration. The model coefficients were calibrated using data collected by automated soil CO2 flux system with clear long-term chamber. The studied ecosystem is a sink of carbon according to modelling and observation results. This study was supported by Russian Foundation for Basic Researches (grant numbers 16-07-01205 and 16-45-700562.

  17. Differences in response of two Sphagnum species to elevated CO2 and nitrogen input

    International Nuclear Information System (INIS)

    Jauhiainen, J.; Vasander, H.; Silvola, J.

    1992-01-01

    Cushions of Sphagnum fuscum and S. angustifolium were grown in the laboratory in four different CO 2 concentrations (350, 700, 1000 and 2000 ppm) and N deposition levels (0, 10, 30 and 100 kg/ha - 1 a - 1). The same N deposition levels were also applied in the field. CO 2 concentration increases both the shoot density and dry mass of S. fuscum but decreased the length increment. There was no net effect on production. For S. angustifolium, shoot density did not alter with elevated CO 2 concentration but the CO 2 induced increment in dry mass and length caused increased production. S. angustifolium suffered from nutrient deficiency on the 0kg/ha - 1 a - 1 treatment and S. fuscum had difficulties to survive at heaviest N load. No clear trends in length increment or cover was noticed in the field study during the first year

  18. Acidity of sphagnum and its relation to chalk and mineral salts

    Energy Technology Data Exchange (ETDEWEB)

    Skene, M

    1915-01-01

    In addition to the criticism and elucidation of various other points, the chief conclusions which may be drawn from the preceding pages are: (1) There is a variation in acidity and in sensitiveness to chalk between the different species of sphagnum. (2) There is a correlation between degree of acidity and degree of sensitiveness. (3) The connection between the two is indirect, not direct. (4) The sphagna thrive in acid solutions: the injurious effect of chalk, and of alkalies in general, is due to the substitution of an alkaline for an acid reaction. (5) Mineral solutions are generally physiologically harmless, but may be ecologically harmful. (6) The sphagna do actually utilize in growth bases held absorbed by the acid compounds of the cell-walls.

  19. Novel insights on the structure and composition of pseudostomata of Sphagnum.

    Science.gov (United States)

    Merced, Amelia

    2015-03-01

    The occurrence of stomata on sporophytes of mosses and hornworts is congruent with a single origin in land plants. Although true stomata are absent in early-divergent mosses, Sphagnum has specialized epidermal cells, pseudostomata, that partially separate but do not open to the inside. This research examined two competing hypotheses that explain the origin of pseudostomata: (1) they are modified stomata, or (2) they evolved from epidermal cells independently from stomata.• Capsule anatomy and ultrastructure of pseudostomata were studied using light and electron microscopy, including immunolocalization of pectins.• Cell walls in pseudostomata are thin, two-layered, and rich in pectins, similar to young moss stomata, including the presence of cuticle on exterior walls. Outer and ventral walls have a thick cuticle that suggests that initial separation of ventral walls involves cuticle deposition as in true stomata. Further mechanical separation between ventral walls does not form a pore and occurs as the capsule dries.• As in moss stomata, pseudostomata wall architecture and behavior facilitate capsule dehydration, shape change, and dehiscence, supporting a common function. The divergent structure and fate of pseudostomata may be explained by the retention of Sphagnum sporophytes within protective leaves until nearly mature. Ultrastructural and immunocytological data suggest that pseudostomata are related to stomata but do not conclusively support either hypothesis. Solving the relationship of early land plants is critical to understanding stomatal evolution. Pseudostomata are structurally and anatomically unique, but their relationship to true stomata remains to be determined. © 2015 Botanical Society of America, Inc.

  20. Bacterial populations and environmental factors controlling cellulose degradation in an acidic Sphagnum peat.

    Science.gov (United States)

    Pankratov, Timofey A; Ivanova, Anastasia O; Dedysh, Svetlana N; Liesack, Werner

    2011-07-01

    Northern peatlands represent a major global carbon store harbouring approximately one-third of the global reserves of soil organic carbon. A large proportion of these peatlands consists of acidic Sphagnum-dominated ombrotrophic bogs, which are characterized by extremely low rates of plant debris decomposition. The degradation of cellulose, the major component of Sphagnum-derived litter, was monitored in long-term incubation experiments with acidic (pH 4.0) peat extracts. This process was almost undetectable at 10°C and occurred at low rates at 20°C, while it was significantly accelerated at both temperature regimes by the addition of available nitrogen. Cellulose breakdown was only partially inhibited in the presence of cycloheximide, suggesting that bacteria participated in this process. We aimed to identify these bacteria by a combination of molecular and cultivation approaches and to determine the factors that limit their activity in situ. The indigenous bacterial community in peat was dominated by Alphaproteobacteria and Acidobacteria. The addition of cellulose induced a clear shift in the community structure towards an increase in the relative abundance of the Bacteroidetes. Increasing temperature and nitrogen availability resulted in a selective development of bacteria phylogenetically related to Cytophaga hutchinsonii (94-95% 16S rRNA gene sequence similarity), which densely colonized microfibrils of cellulose. Among isolates obtained from this community only some subdivision 1 Acidobacteria were capable of degrading cellulose, albeit at a very slow rate. These Acidobacteria represent indigenous cellulolytic members of the microbial community in acidic peat and are easily out-competed by Cytophaga-like bacteria under conditions of increased nitrogen availability. Members of the phylum Firmicutes, known to be key players in cellulose degradation in neutral habitats, were not detected in the cellulolytic community enriched at low pH. © 2011 Society for

  1. Atmospheric Pb and Ti accumulation rates from Sphagnum moss: dependence upon plant productivity.

    Science.gov (United States)

    Kempter, H; Krachler, M; Shotyk, W

    2010-07-15

    The accumulation rates of atmospheric Pb and Ti were obtained using the production rates of Sphagnum mosses collected in four ombrotrophic bogs from two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and one year later the production of plant matter was harvested. Metal concentrations were determined in acid digests using sector field ICP-MS employing well established analytical procedures. Up to 12 samples (40 x 40 cm) were collected per site, and 6-10 sites were investigated per bog. Variations within a given sampling site were in the range 2.3-4x for Pb concentrations, 1.8-2.5x for Ti concentrations, 3-8.3x for Pb/Ti, 5.6-7.8x for Pb accumulation rates, and 2.3-6.4x for Ti accumulation rates. However, the median values of these parameters for the sites (6-10 per bog) were quite consistent. The mosses from the bogs in NBF exhibited significantly greater productivity (187-202 g m(-2) a(-1)) compared to the OB peat bogs (71-91 g m(-2) a(-1)), and these differences had a pronounced effect on the Pb and Ti accumulation rates. Highly productive mosses showed no indication of a "dilution effect" of Pb or Ti concentrations, suggesting that more productive plants were simply able to accumulate more particles from the air. The median rates of net Pb accumulation by the mosses are in excellent agreement with the fluxes obtained by direct atmospheric measurements at nearby monitoring stations in both regions (EMEP and MAPESI data).

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

    Science.gov (United States)

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

    2013-03-01

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

  3. Cellulose and Lignin Carbon Isotope Signatures in Sphagnum Moss Reveal Complementary Environmental Properties

    Science.gov (United States)

    Loisel, J.; Nichols, J. E.; Kaiser, K.; Beilman, D. W.; Yu, Z.

    2016-12-01

    The carbon isotope signature (δ13C) of Sphagnum moss is increasingly used as a proxy for past surface wetness in peatlands. However, conflicting interpretations of these carbon isotope records have recently been published. While the water film hypothesis suggests that the presence of a thick (thin) water film around hollow (hummock) mosses leads to less (more) negative δ13C values, the carbon source hypothesis poses that a significant (insignificant) amount of CH4 assimilation by hollow (hummock) mosses leads to more (less) negative δ13C values. To evaluate these competing mechanisms and their impact on moss δ13C, we gathered 30 moss samples from 6 peatlands in southern Patagonia. Samples were collected along a strong hydrological gradient, from very dry hummocks (80 cm above water table depth) to submerged hollows (5 cm below water surface). These peat bogs have the advantage of being colonized by a single cosmopolitan moss species, Sphagnum magellanicum, limiting potential biases introduced by species-specific carbon discrimination. We measured δ13C from stem cellulose and leaf waxes on the same samples to quantify compound-specific carbon signatures. We found that stem cellulose and leaf-wax lipids were both strongly negatively correlated with moss water content, suggesting a primary role of water film thickness on carbon assimilation. In addition, isotopic fractionation during wax synthesis was greater than for cellulose. This offset decreases as conditions get drier, due to (i) a more effective carbon assimilation, or (ii) CH4 uptake through symbiosis with methanotrophic bacteria within the leaves of wet mosses. Biochemical analysis (carbohydrates, amino acids, hydrophenols, cutin acids) of surface moss are currently being conducted to characterize moss carbon allocation under different hydrological conditions. Overall, this modern calibration work should be of use for interpreting carbon isotope records from peatlands.

  4. High Throughput Sequencing to Detect Differences in Methanotrophic Methylococcaceae and Methylocystaceae in Surface Peat, Forest Soil, and Sphagnum Moss in Cranesville Swamp Preserve, West Virginia, USA

    Science.gov (United States)

    Lau, Evan; Nolan, Edward J.; Dillard, Zachary W.; Dague, Ryan D.; Semple, Amanda L.; Wentzell, Wendi L.

    2015-01-01

    Northern temperate forest soils and Sphagnum-dominated peatlands are a major source and sink of methane. In these ecosystems, methane is mainly oxidized by aerobic methanotrophic bacteria, which are typically found in aerated forest soils, surface peat, and Sphagnum moss. We contrasted methanotrophic bacterial diversity and abundances from the (i) organic horizon of forest soil; (ii) surface peat; and (iii) submerged Sphagnum moss from Cranesville Swamp Preserve, West Virginia, using multiplex sequencing of bacterial 16S rRNA (V3 region) gene amplicons. From ~1 million reads, >50,000 unique OTUs (Operational Taxonomic Units), 29 and 34 unique sequences were detected in the Methylococcaceae and Methylocystaceae, respectively, and 24 potential methanotrophs in the Beijerinckiaceae were also identified. Methylacidiphilum-like methanotrophs were not detected. Proteobacterial methanotrophic bacteria constitute Sphagnum moss) or co-occurred in both Sphagnum moss and peat. This study provides insights into the structure of methanotrophic communities in relationship to habitat type, and suggests that peat and Sphagnum moss can influence methanotroph community structure and biogeography. PMID:27682082

  5. Sphagnum physiology in the context of changing climate: emergent influences of genomics, modelling and host-microbiome interactions on understanding ecosystem function.

    Science.gov (United States)

    Weston, David J; Timm, Collin M; Walker, Anthony P; Gu, Lianhong; Muchero, Wellington; Schmutz, Jeremy; Shaw, A Jonathan; Tuskan, Gerald A; Warren, Jeffrey M; Wullschleger, Stan D

    2015-09-01

    Peatlands harbour more than one-third of terrestrial carbon leading to the argument that the bryophytes, as major components of peatland ecosystems, store more organic carbon in soils than any other collective plant taxa. Plants of the genus Sphagnum are important components of peatland ecosystems and are potentially vulnerable to changing climatic conditions. However, the response of Sphagnum to rising temperatures, elevated CO2 and shifts in local hydrology have yet to be fully characterized. In this review, we examine Sphagnum biology and ecology and explore the role of this group of keystone species and its associated microbiome in carbon and nitrogen cycling using literature review and model simulations. Several issues are highlighted including the consequences of a variable environment on plant-microbiome interactions, uncertainty associated with CO2 diffusion resistances and the relationship between fixed N and that partitioned to the photosynthetic apparatus. We note that the Sphagnum fallax genome is currently being sequenced and outline potential applications of population-level genomics and corresponding plant photosynthesis and microbial metabolic modelling techniques. We highlight Sphagnum as a model organism to explore ecosystem response to a changing climate and to define the role that Sphagnum can play at the intersection of physiology, genetics and functional genomics. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  6. Potential NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Wallen, B; Malmer, N [Lund Univ. (Sweden). Dept. of Plant Ecology

    1997-12-31

    The objective of this research is to test differences in NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species under laboratory conditions. The studied species represent two gradients: the minerotrophy-ombrotrophy (mire margin - mire expanse) gradient, and the hummock-hollow gradient. There are distinct differences in the uptake rate between various Sphagnum species and these differences seem to be due to both structural and environmental factors: (1) on individual basis the highest uptake rate is in species with large capitulum and high number of ion exchange sites i.e. lawn species, (2) on dry mass basis the most effective species are the hummock species though they have a low DM, (3) from the ecosystem point of view, hummock species with high number of shoots per unit area and high uptake rate on dry mass basis, are the most effective species in filtering available nitrogen. (1 ref.)

  7. Active moss biomonitoring of trace elements with Sphagnum girgensohnii moss bags in relation to atmospheric bulk deposition in Belgrade, Serbia

    International Nuclear Information System (INIS)

    Anicic, M.; Tasic, M.; Frontasyeva, M.V.; Tomasevic, M.; Rajsic, S.; Mijic, Z.; Popovic, A.

    2009-01-01

    Active biomonitoring with wet and dry moss bags was used to examine trace element atmospheric deposition in the urban area of Belgrade. The element accumulation capability of Sphagnum girgensohnii Russow was tested in relation to atmospheric bulk deposition. Moss bags were mounted for five 3-month periods (July 2005-October 2006) at three representative urban sites. For the same period monthly bulk atmospheric deposition samples were collected. The concentrations of Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb were determined by instrumental neutron activation analyses and atomic absorption spectrometry. Significant accumulation of most elements occurred in the exposed moss bags compared with the initial moss content. High correlations between the elements in moss and bulk deposits were found for V, Cu, As, and Ni. The enrichment factors of the elements for both types of monitor followed the same pattern at the corresponding sites. - Accumulated trace elements in the moss Sphagnum girgensohnii reflect atmospheric deposition

  8. Greenhouse gas exchange of rewetted bog peat extraction sites and a Sphagnum cultivation site in northwest Germany

    Science.gov (United States)

    Beyer, C.; Höper, H.

    2015-04-01

    During the last decades an increasing area of drained peatlands has been rewetted. Especially in Germany, rewetting is the principal treatment on cutover sites when peat extraction is finished. The objectives are bog restoration and the reduction of greenhouse gas (GHG) emissions. The first sites were rewetted in the 1980s. Thus, there is a good opportunity to study long-term effects of rewetting on greenhouse gas exchange, which has not been done so far on temperate cutover peatlands. Moreover, Sphagnum cultivating may become a new way to use cutover peatlands and agriculturally used peatlands as it permits the economical use of bogs under wet conditions. The climate impact of such measures has not been studied yet. We conducted a field study on the exchange of carbon dioxide, methane and nitrous oxide at three rewetted sites with a gradient from dry to wet conditions and at a Sphagnum cultivation site in NW Germany over the course of more than 2 years. Gas fluxes were measured using transparent and opaque closed chambers. The ecosystem respiration (CO2) and the net ecosystem exchange (CO2) were modelled at a high temporal resolution. Measured and modelled values fit very well together. Annually cumulated gas flux rates, net ecosystem carbon balances (NECB) and global warming potential (GWP) balances were determined. The annual net ecosystem exchange (CO2) varied strongly at the rewetted sites (from -201.7 ± 126.8 to 29.7± 112.7g CO2-C m-2 a-1) due to differing weather conditions, water levels and vegetation. The Sphagnum cultivation site was a sink of CO2 (-118.8 ± 48.1 and -78.6 ± 39.8 g CO2-C m-2 a-1). The annual CH4 balances ranged between 16.2 ± 2.2 and 24.2 ± 5.0g CH4-C m-2 a-1 at two inundated sites, while one rewetted site with a comparatively low water level and the Sphagnum farming site show CH4 fluxes close to 0. The net N2O fluxes were low and not significantly different between the four sites. The annual NECB was between -185.5 ± 126.9 and 49

  9. Greenhouse gas emissions from rewetted bog peat extraction sites and a Sphagnum cultivation site in Northwest Germany

    Science.gov (United States)

    Beyer, C.; Höper, H.

    2014-03-01

    During the last three decades, an increasing area of drained peatlands was rewetted. This was done with the objective to convert these sites from sources back to sinks or, at least, to much smaller sources of greenhouse gases (GHG). However, available data is still scarce, especially on the long-term climatic effects of rewetting of temperate bogs. Moreover, first field trials are established for Sphagnum cultivating (paludiculture) on wet bog sites and an assessment of the climate impact of such measures has not been studied yet. We conducted a field study on the exchange of carbon dioxide, methane and nitrous oxide at three rewetted sites with a gradient from dry to wet conditions and at a Sphagnum cultivation site in NW Germany over more than two years. Gas fluxes were measured using transparent and opaque closed chambers. The ecosystem respiration (CO2) and the net ecosystem exchange (CO2) were modelled in high time resolution using automatically monitored climate data. Measured and modelled values fit very well together (R2 between 0.88 and 0.98). Annually cumulated gas flux rates, net ecosystem carbon balances (NECB) and global warming potential (GWP) balances were determined. The annual net ecosystem exchange (CO2) varied strongly at the rewetted sites (from -201.7 ± 126.8 to 29.7 ± 112.7 g CO2-C m-2 a-1) due to different weather conditions, water level and vegetation. The Sphagnum cultivation site was a sink of CO2 (-118.8 ± 48.1 and -78.6 ± 39.8 g CO2-C m-2 a-1). The yearly CH4 balances ranged between 16.2 ± 2.2 and 24.2 ± 5.0 g CH4-C m-2 a-1 at two inundated sites, while one rewetted site with a comparatively low water level and the Sphagnum farming site show CH4 fluxes close to zero. The net N2O fluxes were low and not significantly different between the four sites. The annual NECB at the rewetted sites was between -183.8 ± 126.9 and 51.6 ± 112.8 g CO2-C m-2 a-1 and at the Sphagnum cultivating site -114.1 ± 48.1 and -75.3 ± 39.8 g CO2-C m-2 a-1

  10. Potential NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species

    Energy Technology Data Exchange (ETDEWEB)

    Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Wallen, B.; Malmer, N. [Lund Univ. (Sweden). Dept. of Plant Ecology

    1996-12-31

    The objective of this research is to test differences in NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species under laboratory conditions. The studied species represent two gradients: the minerotrophy-ombrotrophy (mire margin - mire expanse) gradient, and the hummock-hollow gradient. There are distinct differences in the uptake rate between various Sphagnum species and these differences seem to be due to both structural and environmental factors: (1) on individual basis the highest uptake rate is in species with large capitulum and high number of ion exchange sites i.e. lawn species, (2) on dry mass basis the most effective species are the hummock species though they have a low DM, (3) from the ecosystem point of view, hummock species with high number of shoots per unit area and high uptake rate on dry mass basis, are the most effective species in filtering available nitrogen. (1 ref.)

  11. The potential influence of short-term environmental variability on the composition of testate amoeba communities in Sphagnum peatlands.

    Science.gov (United States)

    Sullivan, Maura E; Booth, Robert K

    2011-07-01

    Testate amoebae are a group of moisture-sensitive, shell-producing protozoa that have been widely used as indicators of changes in mean water-table depth within oligotrophic peatlands. However, short-term environmental variability (i.e., sub-annual) also probably influences community composition. The objective of this study was to assess the potential influence of short-term environmental variability on the composition of testate amoeba communities in Sphagnum-dominated peatlands. Testate amoebae and environmental conditions, including hourly measurements of relative humidity within the upper centimeter of the peatland surface, were examined throughout the 2008 growing season at 72 microsites within 11 peatlands of Pennsylvania and Wisconsin, USA. Relationships among testate amoeba communities, vegetation, depth to water table, pH, and an index of short-term environmental variability (EVI), were examined using nonmetric multidimensional scaling and correlation analysis. Results suggest that EVI influences testate amoeba communities, with some taxa more abundant under highly variable conditions (e.g., Arcella discoides, Difflugia pulex, and Hyalosphenia subflava) and others more abundant when environmental conditions at the peatland surface were relatively stable (e.g., Archerella flavum and Bullinularia indica). The magnitude of environmental variability experienced at the peatland surface appears to be primarily controlled by vegetation composition and density. In particular, sites with dense Sphagnum cover had lower EVI values than sites with loose-growing Sphagnum or vegetation dominated by vascular plants and/or non-Sphagnum bryophytes. Our results suggest that more environmental information may be inferred from testate amoebae than previously recognized. Knowledge of relationships between testate amoebae and short-term environmental variability should lead to more detailed and refined environmental inferences.

  12. Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters.

    Science.gov (United States)

    Krachler, Regina; Krachler, Rudolf F; Wallner, Gabriele; Steier, Peter; El Abiead, Yasin; Wiesinger, Hubert; Jirsa, Franz; Keppler, Bernhard K

    2016-06-15

    Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a (59)Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16-24, 2014), the creeks that run through modified peatlands delivered 11-15μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350-470μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Size matters for violent discharge height and settling speed of Sphagnum spores: important attributes for dispersal potential.

    Science.gov (United States)

    Sundberg, Sebastian

    2010-02-01

    Initial release height and settling speed of diaspores are biologically controlled components which are key to modelling wind dispersal. Most Sphagnum (peat moss) species have explosive spore liberation. In this study, how capsule and spore sizes affect the height to which spores are propelled were measured, and how spore size and spore number of discharged particles relate to settling speed in the aspherical Sphagnum spores. Spore discharge and spore cloud development were filmed in a closed chamber (nine species). Measurements were taken from snapshots at three stages of cloud development. Settling speed of spores (14 species) and clusters were timed in a glass tube. The maximum discharge speed measured was 3.6 m s(-1). Spores reached a maximum height of 20 cm (average: 15 cm) above the capsule. The cloud dimensions at all stages were related positively to capsule size (R(2) = 0.58-0.65). Thus species with large shoots (because they have large capsules) have a dispersal advantage. Half of the spores were released as singles and the rest as clusters (usually two to four spores). Single spores settled at 0.84-1.86 cm s(-1), about 52 % slower than expected for spherical spores with the same diameters. Settling speed displayed a positive curvilinear relationship with spore size, close to predictions by Stokes' law for spherical spores with 68 % of the actual diameters. Light-coloured spores settled slower than dark spores. Settling speed of spore clusters agrees with earlier studies. Effective spore discharge and small, slowly settling spores appear particularly important for species in forested habitats. The spore discharge heights in Sphagnum are among the greatest for small, wind-dispersed propagules. The discharge heights and the slow settling of spores affect dispersal distances positively and may help to explain the wide distribution of most boreal Sphagnum species.

  14. Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome.

    Science.gov (United States)

    Müller, Christina A; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C A; Wellington, Elizabeth M H; Berg, Gabriele

    2015-08-01

    Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses: a meta-analysis.

    Science.gov (United States)

    Limpens, J; Granath, G; Gunnarsson, U; Aerts, R; Bayley, S; Bragazza, L; Bubier, J; Buttler, A; van den Berg, L J L; Francez, A-J; Gerdol, R; Grosvernier, P; Heijmans, M M P D; Hoosbeek, M R; Hotes, S; Ilomets, M; Leith, I; Mitchell, E A D; Moore, T; Nilsson, M B; Nordbakken, J-F; Rochefort, L; Rydin, H; Sheppard, L J; Thormann, M; Wiedermann, M M; Williams, B L; Xu, B

    2011-07-01

    Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased annual precipitation intensified the negative effects of N. The temperature effect was comparable to an experimental application of almost 4 g N m(-2)  yr(-1) for each 1°C increase. Our results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  16. Sensitivity of spectral indices to CO2 fluxes for several plant communities in a Sphagnum-dominated peatland

    International Nuclear Information System (INIS)

    Letendre, J.; Poulin, M.; Rochefort, L.

    2008-01-01

    A study was conducted in which the relationship between spectral indices and carbon dioxide (CO 2 ) fluxes was tested for different communities in a Sphagnum-dominated peatland. This paper focused on the remote sensing approach that was used to directly link spectral indices to CO 2 fluxes to highlight the potential of remote sensing for mapping the spatial distribution of CO 2 fluxes. Carbon exchange in these ecosystems has become an environmental concern since peatlands play a key role in the global carbon cycle. A portable climate-controlled chamber was used to measure fluxes while simultaneously recording reflectance with a hand-held spectroradiometer. A laboratory experiment was also conducted to find a water-related index that most correlated with Sphagnum water content in order to regulate the normalized difference vegetation index (NDVI) values obtained in the field. The laboratory experiment showed a strong correlation between Sphagnum water content and all spectral indices, notably the water index (WI), normalized difference water index (NDWI), and relative depth index (RDI). The water index was chosen to regulate NDVI values. This paper described the indices that were tested in the field for CO 2 flux estimations. NDVI alone was found to be a poor predictor of net ecosystem exchange. The relationship between CO 2 fluxes and narrow band chlorophyll indices was reasonably well adjusted. It was concluded that the chlorophyll indices may be the most promising for mapping the spatial distribution of CO 2 fluxes in the future. 62 refs., 2 tabs., 4 figs

  17. Assessing environmental attributes and effects of climate change on Sphagnum peatland distributions in North America using single- and multi-species models.

    Science.gov (United States)

    Oke, Tobi A; Hager, Heather A

    2017-01-01

    The fate of Northern peatlands under climate change is important because of their contribution to global carbon (C) storage. Peatlands are maintained via greater plant productivity (especially of Sphagnum species) than decomposition, and the processes involved are strongly mediated by climate. Although some studies predict that warming will relax constraints on decomposition, leading to decreased C sequestration, others predict increases in productivity and thus increases in C sequestration. We explored the lack of congruence between these predictions using single-species and integrated species distribution models as proxies for understanding the environmental correlates of North American Sphagnum peatland occurrence and how projected changes to the environment might influence these peatlands under climate change. Using Maximum entropy and BIOMOD modelling platforms, we generated single and integrated species distribution models for four common Sphagnum species in North America under current climate and a 2050 climate scenario projected by three general circulation models. We evaluated the environmental correlates of the models and explored the disparities in niche breadth, niche overlap, and climate suitability among current and future models. The models consistently show that Sphagnum peatland distribution is influenced by the balance between soil moisture deficit and temperature of the driest quarter-year. The models identify the east and west coasts of North America as the core climate space for Sphagnum peatland distribution. The models show that, at least in the immediate future, the area of suitable climate for Sphagnum peatland could expand. This result suggests that projected warming would be balanced effectively by the anticipated increase in precipitation, which would increase Sphagnum productivity.

  18. A new genus and new species of felt scales (Homoptera: Coccinea: Eriococcidae from Tierra del Fuego (Chile

    Directory of Open Access Journals (Sweden)

    Ilya A. Gavrilov-Zimin

    2016-10-01

    Full Text Available Telmatococcus igniumterrae gen. nov. et sp. nov. is described and illustrated based on the material collected from a sphagnum bog in the extreme southern part of South America (Tierra del Fuego. The new monotypic genus differs from all known genera of Eriococcidae in having short cylindrical truncated setae of the anal apparatus and pouches with numerous quinquelocular pores near the anal apparatus. The habitat of the new taxon is characterized.

  19. Molybdenum-based diazotrophy in a Sphagnum peatland in northern Minnesota.

    Science.gov (United States)

    Warren, Melissa J; Lin, Xueju; Gaby, John C; Kretz, Cecilia B; Kolton, Max; Morton, Peter L; Pett-Ridge, Jennifer; Weston, David J; Schadt, Christopher W; Kostka, Joel E; Glass, Jennifer B

    2017-06-30

    Microbial N 2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO 2 and susceptible to changing climate. The objectives of this study were: (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in a ombrotrophic Sphagnum -dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O 2 , CO 2 , CH 4 ) on potential rates of diazotrophy measured by acetylene (C 2 H 2 ) reduction and 15 N 2 incorporation. Molecular analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria ( Bradyrhizobiaceae and Beijerinckiaceae ). Despite higher dissolved vanadium (V; 11 nM) than molybdenum (Mo; 3 nM) in surface peat, a combination of metagenomic, amplicon sequencing and activity measurements indicated that Mo-containing nitrogenases dominate over the V-containing form. Acetylene reduction was only detected in surface peat exposed to light, with the highest rates observed in peat collected from hollows with the highest water content. Incorporation of 15 N 2 was suppressed 90% by O 2 and 55% by C 2 H 2 , and was unaffected by CH 4 and CO 2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C 2 H 2 -sensitive and C 2 H 2 -insensitive microbes that are more active at low O 2 and show similar activity at high and low CH 4 Importance Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum -dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process remain in question. Our findings indicate that oxygen levels and photosynthetic activity override low

  20. Modelling hydrological processes and dissolved organic carbon dynamics in a rehabilitated Sphagnum-dominated peatland

    Science.gov (United States)

    Bernard-Jannin, Léonard; Binet, Stéphane; Gogo, Sébastien; Leroy, Fabien; Perdereau, Laurent; Laggoun-Défarge, Fatima

    2017-04-01

    Sphagnum-dominated peatlands represent a global major stock of carbon (C). Dissolved organic carbon (DOC) exports through runoff and leaching could reduce their potential C sink function and impact downstream water quality. DOC production in peatlands is strongly controlled by the hydrology, especially water table depth (WTD). Therefore, disturbances such as drainage can lead to increase DOC exports by lowering the WTD. Hydrological restoration (e.g. rewetting) can be undertaken to restore peatland functioning with an impact on DOC exports. The objective of this study is to assess the impact of drainage and rewetting on hydrological processes and their interactions with DOC dynamics in a Sphagnum dominated peatland. A hydrological model has been applied to a drained peatland (La Guette, France) which experienced a rewetting action on February 2014 and where WTD has been recorded in four piezometers at a 15 min time step since 2009. In addition, DOC concentrations in the peatland have been measured 6 times a year since 2014. The hydrological model is a WTD dependent reservoir model composed by two reservoirs representing the micro and macro porosity of the peatland (Binet et al., 2013). A DOC production module in both reservoirs was implemented based on temperature and WTD. The model was calibrated against WTD and DOC concentrations for each piezometer. The results show that the WTD in the study area is strongly affected by local meteorological conditions that could hide the effect of the rewetting action. The preliminary results evidenced that an additional source of water, identified as groundwater supply originating from the surrounding sandy layer aquifer, is necessary to maintain the water balance, especially during wet years (NS>0.8). Finally, the DOC module was able to describe DOC concentrations measured in the peatland and could be used to assess the impact of rewetting on DOC dynamics at different locations and to identify the factors of control of DOC

  1. Acrotelm pedogenesis of a Sphagnum bog is reflected in effective unsaturated hydraulic properties

    Science.gov (United States)

    Weber, Tobias K. D.; Iden, Sascha C.; Durner, Wolfgang

    2017-04-01

    In ombrotrophic peatlands, the moisture content of the vadose zone (acrotelm) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Whether peatlands act as sinks or sources of atmospheric carbon thus relies on variably saturated flow processes. Modeling of these processes is crucial in assessing effects of changed environmental conditions on the future development of these ecosystems. The Richards equation (RE) is the standard model for water flow in soils, but it is not clear whether it can be applied to simulate water flow in live Sphagnum moss. To check the suitability of the RE to describe the water dynamics in drying moss and peat we conducted transient laboratory evaporation experiments on undisturbed samples from the entire acrotelm. The experimental data consisted of measured pressure heads in two depths and water fluxes, and were evaluated by inverse modelling using the RE as process model. The results showed that the measurements could be matched very well only if the soil hydraulic properties (SHPs) were represented by a suitable model. A successful parameterisation of the SHPs of the moss was based on pore-size distributions (PSD) which combine three distinct pore systems of the Sphagnum moss, reflecting an inter-, intra-, and inner-plant pore space. We had to extend the traditional van Genuchten-Mualem model to account for non-capillary water storage and flow to obtain consistent descriptions of the observations. For the deeper samples, the pedogenesis of the acrotelm, a process of compaction and biochemical degradation of the solid matrix, had considerably impact on the shape of the SHPs. The collapse of the inter-plant pores and their filling with smaller particles led gradually to bi-modal PSDs with increasing depth. This coincides with a homogenisation and a considerably reduction in horizontal variability of SHPs at greater depths. We conclude that the RE with adequate representation of SHPs is a valid process

  2. Effect of Water Content Components on Desiccation and Recovery in Sphagnum Mosses

    Science.gov (United States)

    Hájek, Tomáš; Beckett, Richard P.

    2008-01-01

    Background and Aims The basic parameters of water relations were measured in Sphagnum mosses. The relationships of these parameters to the photosynthetic response to desiccation and the ecology of these mosses were then tested. Methods The water relations parameters of six Sphagnum species (mosses typical of wet habitats) and Atrichum androgynum (a moss more typical of mesophytic conditions) were calculated from pressure–volume isotherms. Photosynthetic properties during and after moderate desiccation were monitored by chlorophyll fluorescence. Key Results When desiccated, the hummock-forming species S. fuscum and S. magellanicum lost more water before turgor started dropping than other sphagna inhabiting less exposed habitats (73 % compared with 56 % on average). Osmotic potentials at full turgor were similar in all species, with an average value of −1·1 MPa. Hummock sphagna had clearly more rigid cell walls than species of wet habitats (ε = 3·55 compared with 1·93 MPa). As a result, their chlorophyllous cells lost turgor at higher relative water contents (RWCs) than species of wet habitats (0·61 compared with 0·46) and at less negative osmotic potentials (–2·28 compared with −3·00 MPa). During drying, ΦPSII started declining earlier in hummock species (at an RWC of 0·65 compared with 0·44), and Fv/Fm behaved similarly. Compared with other species, hummock sphagna desiccated to −20 or −40 MPa recovered more completely after rehydration. Atrichum androgynum responded to desiccation similarly to hummock sphagna, suggesting that their desiccation tolerance may have a similar physiological basis. Conclusions Assuming a fixed rate of desiccation, the higher water-holding capacities of hummock sphagna will allow them to continue metabolism for longer than other species. While this could be viewed as a form of ‘desiccation avoidance’, hummock species also recover faster than other species during rehydration, suggesting that they have higher

  3. The effect of Sphagnum farming on the greenhouse gas balance of donor and propagation areas, irrigation polders and commercial cultivation sites

    Science.gov (United States)

    Oestmann, Jan; Tiemeyer, Bärbel

    2017-04-01

    Drainage of peatlands for agriculture, forestry and peat extraction turned these landscapes into hotspots of greenhouse gas emissions. Climate protection now fosters rewetting projects to restore the natural peatland function as a sink of atmospheric carbon. One possible way to combine ecological and economical goals is Sphagnum farming, i.e. the cultivation of Sphagnum mosses as high-quality substrates for horticulture. This project scientifically evaluates the attempt of commercial Sphagnum farming on former peat extraction sites in north-western Germany. The exchange of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) of the whole peatland-based production chain comprising a donor mire, a propagation area, an irrigation polder and a cultivation site will be determined in a high temporal resolution for two years using manual chambers. This will allow evaluating the greenhouse gas balance of Sphagnum farming sites in comparison to near-natural sites and the potential of Sphagnum farming for restoring drained peatlands to sinks of atmospheric carbon. The influence of different irrigation techniques will also be tested. Additionally, selected plots will be equipped with open top chambers in order to examine the greenhouse gas exchange under potential future climate change conditions. Finally, a 13C pulse labeling experiment will make it possible to trace the newly sequestered CO2 in biomass, soil, respiration and dissolved organic carbon.

  4. Development of a Waste Water Regenerative System - Using Sphagnum Moss Ion-exchange

    Science.gov (United States)

    McKeon, M.; Wheeler, R.; Leahy, Jj

    The use of inexpensive, light weight and regenerative systems in an enclosed environment is of great importance to sustained existence in such habitats as the International Space Station, Moon or even Mars. Many systems exist which utilise various synthetic ion exchangers to complete the process of waste water clean-up. These systems do have a very good exchange rate for cations but a very low exchange rate for anions. They also have a maximum capacity before they need regeneration. This research proposes a natural alternative to these synthetic ion-exchangers that utilises one of natures greatest ion-exchangers, that of Sphagnum Moss. Sphagna can be predominantly found in the nutrient poor environment of Raised Bogs, a type of isolated wetland with characteristic low pH and little interaction with the surrounding water table. All nutrients come from precipitation. The sphagna have developed as the bog's sponges, soaking up all available nutrients (both cation & anion) from the precipitation and eventually distributing them to the surrounding flora and fauna, through the water. The goal of this research is to use this ability in the processing of waste water from systems similar to isolated microgravity environments, to produce clean water for reuse in these environments. The nutrients taken up by the sphagna will also be utilised as a growth medium for cultivar growth, such as those selected for hydroponics' systems.

  5. The narrow endemic Norwegian peat moss Sphagnum troendelagicum originated before the last glacial maximum.

    Science.gov (United States)

    Stenøien, H K; Shaw, A J; Stengrundet, K; Flatberg, K I

    2011-02-01

    It is commonly found that individual hybrid, polyploid species originate recurrently and that many polyploid species originated relatively recently. It has been previously hypothesized that the extremely rare allopolyploid peat moss Sphagnum troendelagicum has originated multiple times, possibly after the last glacial maximum in Scandinavia. This conclusion was based on low linkage disequilibrium in anonymous genetic markers within natural populations, in which sexual reproduction has never been observed. Here we employ microsatellite markers and chloroplast DNA (cpDNA)-encoded trnG sequence data to test hypotheses concerning the origin and evolution of this species. We find that S. tenellum is the maternal progenitor and S. balticum is the paternal progenitor of S. troendelagicum. Using various Bayesian approaches, we estimate that S. troendelagicum originated before the Holocene but not before c. 80,000 years ago (median expected time since speciation 40 000 years before present). The observed lack of complete linkage disequilibrium in the genome of this species suggests cryptic sexual reproduction and recombination. Several lines of evidence suggest multiple origins for S. troendelagicum, but a single origin is supported by approximate Bayesian computation analyses. We hypothesize that S. troendelagicum originated in a peat-dominated refugium before last glacial maximum, and subsequently immigrated to central Norway by means of spore flow during the last thousands of years.

  6. Peatland succession induces a shift in the community composition of Sphagnum-associated active methanotrophs.

    Science.gov (United States)

    Putkinen, Anuliina; Larmola, Tuula; Tuomivirta, Tero; Siljanen, Henri M P; Bodrossy, Levente; Tuittila, Eeva-Stiina; Fritze, Hannu

    2014-06-01

    Sphagnum-associated methanotrophs (SAM) are an important sink for the methane (CH4) formed in boreal peatlands. We aimed to reveal how peatland succession, which entails a directional change in several environmental variables, affects SAM and their activity. Based on the pmoA microarray results, SAM community structure changes when a peatland develops from a minerotrophic fen to an ombrotrophic bog. Methanotroph subtypes Ia, Ib, and II showed slightly contrasting patterns during succession, suggesting differences in their ecological niche adaptation. Although the direct DNA-based analysis revealed a high diversity of type Ib and II methanotrophs throughout the studied peatland chronosequence, stable isotope probing (SIP) of the pmoA gene indicated they were active mainly during the later stages of succession. In contrast, type Ia methanotrophs showed active CH4 consumption in all analyzed samples. SIP-derived (13)C-labeled 16S rRNA gene clone libraries revealed a high diversity of SAM in every succession stage including some putative Methylocella/Methyloferula methanotrophs that are not detectable with the pmoA-based approach. In addition, a high diversity of 16S rRNA gene sequences likely representing cross-labeled nonmethanotrophs was discovered, including a significant proportion of Verrucomicrobia-related sequences. These results help to predict the effects of changing environmental conditions on SAM communities and activity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  7. Lateral extension in Sphagnum mires along the southern margin of the boreal region, Western Siberia

    International Nuclear Information System (INIS)

    Peregon, A; Uchida, M; Yamagata, Y

    2009-01-01

    Although recent studies have recognized Northern Eurasian ecosystems as an important carbon reservoir, little is known about the forest-peatland interactions in a boreal environment induced by ongoing climatic changes. This study focuses on the evaluation of both the long-term and contemporary trends of land-cover changes and rates of lateral extension of peat-accumulating wetlands toward the adjacent forests, estimated at the southern climatic range of the Sphagnum-dominated mires in Western Siberia. We used the radiocarbon dates and stratigraphy of peat sediments from seven peat cores, analyzed at two types of forest-peatland ecotones, which are located close to each other but differ by topography and composition of their plant communities. The rate of lateral extension was found in a wide range varying from 2.3 to 791.7 cm yr -1 . It was observed to be rapid during the initial stage of mire development, but to have slowed down over the last 2000-3000 yr. Our results, therefore, strongly contradict the concept of progressive peat accumulation throughout the late Holocene and contribute to our knowledge about ongoing land-cover change in the natural ecosystems of the Northern hemisphere.

  8. Abiotic reaction of iodate with sphagnum peat and other natural organic matter

    International Nuclear Information System (INIS)

    Steinberg, S.M.; Kimble, G.; Schmett, G.T.; Emerson, D.W.; Turner, M.F.; Rudin, M.

    2008-01-01

    Previous studies have shown that iodine (including 129 I) can be strongly retained in organic-rich surface soils and sediment and that a large fraction of soluble iodine may be associated with dissolved humic material. Iodate (IO 3 - ) reacts with natural organic matter (NOM) producing either hypoiodous acid (HIO) or I 2 as an intermediate. This intermediate is subsequently incorporated into the organic matter. Based on reactions of model compounds, we infer that iodine reacts with peat by aromatic substitution of hydrogen on phenolic constituents of the peat. Alternatively, the intermediate, HIO or I 2 , may be reduced to iodide (I - ). The pH (and temperature) dependence of the IO 3 - reaction (reduction) has been explored with sphagnum peat, alkali lignin, and several model compounds. The incorporation of iodine into NOM has been verified by pyrolysis gas chromatography/mass spectrometry (GC/MS). Model compound studies indicate that reduction of IO 3 - to HIO may result from reaction with hydroquinone (or semiquinone) moieties of the peat. (author)

  9. Mycobacterium minnesotense sp. nov., a photochromogenic bacterium isolated from sphagnum peat bogs.

    Science.gov (United States)

    Hannigan, Geoffrey D; Krivogorsky, Bogdana; Fordice, Daniel; Welch, Jacqueline B; Dahl, John L

    2013-01-01

    Several intermediate-growing, photochromogenic bacteria were isolated from sphagnum peat bogs in northern Minnesota, USA. Acid-fast staining and 16S rRNA gene sequence analysis placed these environmental isolates in the genus Mycobacterium, and colony morphologies and PCR restriction analysis patterns of the isolates were similar. Partial sequences of hsp65 and dnaJ1 from these isolates showed that Mycobacterium arupense ATCC BAA-1242(T) was the closest mycobacterial relative, and common biochemical characteristics and antibiotic susceptibilities existed between the isolates and M. arupense ATCC BAA-1242(T). However, compared to nonchromogenic M. arupense ATCC BAA-1242(T), the environmental isolates were photochromogenic, had a different mycolic acid profile and had reduced cell-surface hydrophobicity in liquid culture. The data reported here support the conclusion that the isolates are representatives of a novel mycobacterial species, for which the name Mycobacterium minnesotense sp. nov. is proposed. The type strain is DL49(T) (=DSM 45633(T) = JCM 17932(T) = NCCB 100399(T)).

  10. Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium.

    Science.gov (United States)

    Delaine, Maxence; Bernard, Nadine; Gilbert, Daniel; Recourt, Philippe; Armynot du Châtelet, Eric

    2017-06-01

    Testate amoebae are free-living shelled protists that build a wide range of shells with various sizes, shapes, and compositions. Recent studies showed that xenosomic testate amoebae shells could be indicators of atmospheric particulate matter (PM) deposition. However, no study has yet been conducted to assess the intra-specific mineral, organic, and biologic grain diversity of a single xenosomic species in a natural undisturbed environment. This study aims at providing new information about grain selection to develop the potential use of xenosomic testate amoebae shells as bioindicators of the multiple-origin mineral/organic diversity of their proximal environment. To fulfil these objectives, we analysed the shell content of 38 Bullinularia indica individuals, a single xenosomic testate amoeba species living in Sphagnum capillifolium, by scanning electron microscope (SEM) coupled with X-ray spectroscopy. The shells exhibited high diversities of mineral, organic, and biomineral grains, which confirms their capability to recycle xenosomes. Mineral grain diversity and size of B. indica matched those of the atmospheric natural mineral PM deposited in the peatbog. Calculation of grain size sorting revealed a discrete selection of grains agglutinated by B. indica. These results are a first step towards understanding the mechanisms of particle selection by xenosomic testate amoebae in natural conditions. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. The narrow endemic Norwegian peat moss Sphagnum troendelagicum originated before the last glacial maximum

    Science.gov (United States)

    Stenøien, H K; Shaw, A J; Stengrundet, K; Flatberg, K I

    2011-01-01

    It is commonly found that individual hybrid, polyploid species originate recurrently and that many polyploid species originated relatively recently. It has been previously hypothesized that the extremely rare allopolyploid peat moss Sphagnum troendelagicum has originated multiple times, possibly after the last glacial maximum in Scandinavia. This conclusion was based on low linkage disequilibrium in anonymous genetic markers within natural populations, in which sexual reproduction has never been observed. Here we employ microsatellite markers and chloroplast DNA (cpDNA)-encoded trnG sequence data to test hypotheses concerning the origin and evolution of this species. We find that S. tenellum is the maternal progenitor and S. balticum is the paternal progenitor of S. troendelagicum. Using various Bayesian approaches, we estimate that S. troendelagicum originated before the Holocene but not before c. 80 000 years ago (median expected time since speciation 40 000 years before present). The observed lack of complete linkage disequilibrium in the genome of this species suggests cryptic sexual reproduction and recombination. Several lines of evidence suggest multiple origins for S. troendelagicum, but a single origin is supported by approximate Bayesian computation analyses. We hypothesize that S. troendelagicum originated in a peat-dominated refugium before last glacial maximum, and subsequently immigrated to central Norway by means of spore flow during the last thousands of years. PMID:20717162

  12. Lateral extension in Sphagnum mires along the southern margin of the boreal region, Western Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Peregon, A; Uchida, M; Yamagata, Y, E-mail: anna.peregon@nies.go.j [Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

    2009-10-15

    Although recent studies have recognized Northern Eurasian ecosystems as an important carbon reservoir, little is known about the forest-peatland interactions in a boreal environment induced by ongoing climatic changes. This study focuses on the evaluation of both the long-term and contemporary trends of land-cover changes and rates of lateral extension of peat-accumulating wetlands toward the adjacent forests, estimated at the southern climatic range of the Sphagnum-dominated mires in Western Siberia. We used the radiocarbon dates and stratigraphy of peat sediments from seven peat cores, analyzed at two types of forest-peatland ecotones, which are located close to each other but differ by topography and composition of their plant communities. The rate of lateral extension was found in a wide range varying from 2.3 to 791.7 cm yr{sup -1}. It was observed to be rapid during the initial stage of mire development, but to have slowed down over the last 2000-3000 yr. Our results, therefore, strongly contradict the concept of progressive peat accumulation throughout the late Holocene and contribute to our knowledge about ongoing land-cover change in the natural ecosystems of the Northern hemisphere.

  13. Chromobacterium sphagni sp. nov., an insecticidal bacterium isolated from Sphagnum bogs.

    Science.gov (United States)

    Blackburn, Michael B; Farrar, Robert R; Sparks, Michael E; Kuhar, Daniel; Mitchell, Ashaki; Gundersen-Rindal, Dawn E

    2017-09-01

    Sixteen isolates of Gram-reaction-negative, motile, violet-pigmented bacteria were isolated from Sphagnum bogs in West Virginia and Maine, USA. 16S rRNA gene sequences and fatty acid analysis revealed a high degree of relatedness among the isolates, and genome sequencing of two isolates, IIBBL 14B-1T and IIBBL 37-2 (from West Virginia and Maine, respectively), revealed highly similar genomic sequences. The average nucleotide identity (gANI) calculated for these two isolates was found to be in excess of 99 %, but did not exceed 88 % when comparing either isolate with genomic sequences of Chromobacterium violaceum ATCC 12472T, C. haemolyticum DSM 19808T, C. piscinae ND17, C. subtsugae PRAA4-1T, C. vaccinii MWU205T or C. amazonense CBMAI 310T. Collectively, gANI and 16S rRNA gene sequence comparisons suggested that isolates IIBBL 14B-1T and IIBBL 37-2 were most closely related to C. subtsugae, but represented a distinct species. We propose the name Chromobacterium sphagni sp. nov. for this taxon; the type strain is IIBBL 14B-1T (=NRRL B-67130T=JCM 31882T).

  14. Abundance, diversity and depth distribution of Planctomycetes in northern Sphagnum-dominated wetlands

    Directory of Open Access Journals (Sweden)

    Svetlana N. Dedysh

    2012-01-01

    Full Text Available Members of the bacterial phylum Planctomycetes inhabit various aquatic and terrestrial environments. In this study, fluorescence in situ hybridization (FISH was applied to assess the abundance and depth distribution of these bacteria in nine different Sphagnum-dominated wetlands of Northern Russia. Planctomycetes were most abundant in the oxic part of peat bog profiles. The respective cell numbers were in the range 1.1-6.7×107 cells per gram of wet peat, comprising 2 to 14% of total bacterial cells and displaying linear correlation to the peat water pH. Most peatland sites showed a sharp decline of planctomycete abundance with depth, while in two particular sites this decline was followed by a second population maximum in an anoxic part of the bog profile. Oxic peat layers were dominated by representatives of the Isosphaera-Singulisphaera group, while anoxic part of the bog profile was inhabited mostly by Zavarzinella- and Pirellula-like planctomycetes. Phylogenetically related bacteria of the candidate division OP3 were detected in both oxic and anoxic peat with cell densities of 0.6-4.6×106 cells per gram of wet peat.

  15. Sensitivity of spectral indices to CO{sub 2} fluxes for several plant communities in a Sphagnum-dominated peatland

    Energy Technology Data Exchange (ETDEWEB)

    Letendre, J.; Poulin, M.; Rochefort, L. [Laval Univ., Quebec City, PQ (Canada). Dept. de Phytologie, Peatland Ecology and Research Group

    2008-07-01

    A study was conducted in which the relationship between spectral indices and carbon dioxide (CO{sub 2}) fluxes was tested for different communities in a Sphagnum-dominated peatland. This paper focused on the remote sensing approach that was used to directly link spectral indices to CO{sub 2} fluxes to highlight the potential of remote sensing for mapping the spatial distribution of CO{sub 2} fluxes. Carbon exchange in these ecosystems has become an environmental concern since peatlands play a key role in the global carbon cycle. A portable climate-controlled chamber was used to measure fluxes while simultaneously recording reflectance with a hand-held spectroradiometer. A laboratory experiment was also conducted to find a water-related index that most correlated with Sphagnum water content in order to regulate the normalized difference vegetation index (NDVI) values obtained in the field. The laboratory experiment showed a strong correlation between Sphagnum water content and all spectral indices, notably the water index (WI), normalized difference water index (NDWI), and relative depth index (RDI). The water index was chosen to regulate NDVI values. This paper described the indices that were tested in the field for CO{sub 2} flux estimations. NDVI alone was found to be a poor predictor of net ecosystem exchange. The relationship between CO{sub 2} fluxes and narrow band chlorophyll indices was reasonably well adjusted. It was concluded that the chlorophyll indices may be the most promising for mapping the spatial distribution of CO{sub 2} fluxes in the future. 62 refs., 2 tabs., 4 figs.

  16. Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters

    International Nuclear Information System (INIS)

    Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Steier, Peter; El Abiead, Yasin; Wiesinger, Hubert; Jirsa, Franz; Keppler, Bernhard K.

    2016-01-01

    Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a "5"9Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16–24, 2014), the creeks that run through modified peatlands delivered 11–15 μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350–470 μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. - Highlights: • We report that peat-bogs are sources of bio-available iron to marine algae. • This iron is effectively chelated with aquatic humic acids. • The radiocarbon age of the iron-carrying aquatic humic acids was up to 550 years. • Analysis was focused on mixing experiments of iron-rich creek water with seawater. • Drained peatlands with

  17. A comparison of PCR-based markers for the molecular identification of Sphagnum species of the section Acutifolia

    Directory of Open Access Journals (Sweden)

    Jakub Sawicki

    2011-07-01

    Full Text Available RAPDs, ISJs, ISSRs, ITS and katGs were applied to determine genetic relationships between common Sphagnum species of the section Acutifolia. Twenty populations were genotyped using ten ISJ primers, 12 pairs of katG primers, 10 ISSR and 10 RAPD primers, and a restriction analysis of ITS1 and ITS2. ISSR and katG markers revealed the greatest number of species-specific bands. An analysis of ITS1 and ITS2 regions with restriction enzymes also proved to be a highly effective tool for species identification.

  18. A new Cernosvitoviella species (Clitellata: Enchytraeidae) and its comparison with other Cernosvitoviella species from Sphagnum mires in Hungary.

    Science.gov (United States)

    Dózsa-Farkas, Klára; Csitári, Bianka; Felföldi, Tamás

    2017-04-18

    Results of a comparative investigation on five Cernosvitoviella species from Hungarian Sphagnum mires including their distribution and the description of a new species, Cernosvitoviella farkasi sp. n., are presented in this paper. Cernosvitoviella atrata, C. aggtelekiensis, C. crassoductus and C. farkasi sp. n. could be easily distinguished from each other based on both morphological and molecular taxonomic analyses. However, C. minor seems to be a species complex on the basis of these investigations, so it was referred as C. minor sensu lato. The status of the C. minor variants requires further studies.

  19. Net photosynthesis in Sphagnum mosses has increased in response to the last century's 100 ppm increase in atmospheric CO2

    Science.gov (United States)

    Serk, Henrik; Nilsson, Mats; Schleucher, Jurgen

    2017-04-01

    Peatlands store >25% of the global soil C pool, corresponding to 1/3 of the contemporary CO2-C in the atmosphere. The majority of the accumulated peat is made up by remains of Sphagnum peat mosses. Thus, understanding how various Sphagnum functional groups respond, and have responded, to increasing atmospheric CO2 and temperature constitutes a major challenge for our understanding of the role of peatlands under a changing climate. We have recently demonstrated (Ehlers et al., 2015, PNAS) that the abundance ratio of two deuterium isotopomers (molecules carrying D at specific intramolecular positions, here D6R/S) of photosynthetic glucose reflects the ratio of oxygenation to carboxylation metabolic fluxes at Rubisco. The photosynthetic glucose is prepared from various plant carbohydrates including cellulose. This finding has been established in CO2 manipulation experiments and observed in carbohydrate derived glucose isolated from herbarium samples of all investigated C-3 species. The isotopomer ratio is connected to specific enzymatic processes thus allowing for mechanistic implicit interpretations. Here we demonstrate a clear increase in net photosynthesis of Sphagnum fuscum in response to the increase of 100 ppm CO2 during the last century as deduced from analysis on S. fuscum remains from peat cores. The D6R/S ratio declines from bottom to top in peat cores, indicating CO2-driven reduction of photorespiration in contemporary moss biomass. In contrast to the hummock-forming S. fuscum, hollow-growing species, e.g. S. majus did not show this response or gave significantly weaker response, suggesting important ecological consequences of rising CO2 on peatland ecosystem services. We hypothesize that photosynthesis in hollow-growing species under water saturation is fully or partly disconnected from the atmospheric CO2 partial pressure and thus showing weaker or no response to increased atmospheric CO2. To further test the field observations we grow both hummock and

  20. Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters

    Energy Technology Data Exchange (ETDEWEB)

    Krachler, Regina, E-mail: regina.krachler@univie.ac.at [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Krachler, Rudolf F.; Wallner, Gabriele [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Steier, Peter [Isotope Research and Nuclear Physics, University of Vienna, Währingerstraße 17, 1090 Vienna (Austria); El Abiead, Yasin; Wiesinger, Hubert [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); University of Johannesburg, Department of Zoology, P. O. Box 524, Auckland Park 2006 (South Africa); Keppler, Bernhard K. [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria)

    2016-06-15

    Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a {sup 59}Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16–24, 2014), the creeks that run through modified peatlands delivered 11–15 μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350–470 μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. - Highlights: • We report that peat-bogs are sources of bio-available iron to marine algae. • This iron is effectively chelated with aquatic humic acids. • The radiocarbon age of the iron-carrying aquatic humic acids was up to 550 years. • Analysis was focused on mixing experiments of iron-rich creek water with seawater. • Drained

  1. Soil temperature synchronisation improves estimation of daily variation of ecosystem respiration in Sphagnum peatlands

    Science.gov (United States)

    D'Angelo, Benoît; Gogo, Sébastien; Le Moing, Franck; Jégou, Fabrice; Guimbaud, Christophe; Laggoun, Fatima

    2015-04-01

    Ecosystem respiration (ER) is a key process in the global C cycle and thus, plays an important role in the climate regulation. Peatlands contain a third of the world soil C in spite of their relatively low global area (3% of land area). Although these ecosystems represent potentially a significant source of C under global change, they are still not taken into account accordingly in global climatic models. Therefore, ER variations have to be accounted for, especially by estimating its dependence to temperature.s The relationship between ER and temperature often relies only on one soil temperature depth and the latter is generally taken in the first 10 centimetres. Previous studies showed that the temperature dependence of ER depends on the depth at which the temperature is recorded. The depth selection for temperature measurement is thus a predominant issue. A way to deal with this is to analyse the time-delay between ER and temperature. The aim of this work is to assess whether using synchronised data in models leads to a better ER daily variation estimation than using non-synchronised data. ER measurements were undertaken in 2013 in 4 Sphagnum peatlands across France: La Guette (N 47°19'44', E 2°17'04', 154m) in July, Landemarais (N 48°26'30', E -1°10'54', 145m) in August, Frasne (N 46°49'35', E 6°10'20', 836m) in September, and Bernadouze (N 42°48'09', E 1°25'24', 1500m) in October. A closed method chamber was used to measure ER hourly during 72 hours in each of the 4 replicates installed in each site. Average ER ranged from 1.75 μmol m-2 s-1 to 6.13 μmol m-2 s-1. A weather station was used to record meteorological data and soil temperature profiles (5, 10, 20 and 30 cm). Synchronised data were determined for each depth by selecting the time-delay leading to the best correlation between ER and soil temperature. The data were used to simulate ER according to commonly used equations: linear, exponential with Q10, Arrhenius, Lloyd and Taylor. Models

  2. Investigating the internal structure of four Azorean Sphagnum bogs using ground-penetrating radar

    Directory of Open Access Journals (Sweden)

    D. Pereira

    2017-08-01

    Full Text Available This study evaluates the applicability of ground penetrating radar (GPR as a technique for determining the thickness and internal structure of four peat deposits on Terceira Island (Azores archipelago, mid-Atlantic region. The peatlands studied are all Sphagnum mires located above 500 m a.s.l., but they differ hydrogenetically and in their degree of naturalness. Radargrams for all four bogs, obtained using both 100 MHz and 500 MHz GPR antennae, are presented and compared. The radargram data were validated against peat characteristics (bulk density, von Post H, US method obtained by direct sampling (‘open cores’ across the whole peat profile at each site. A scheme of ‘soft scoring’ for degree of naturalness (DN of the peatland was developed and used as an additional validation factor. The GPR data were positively correlated with DN, and relationships between GPR data, peat bulk density and degree of humification (H were also found. From the radargrams it was possible to distinguish the interface between the peat and the mineral substratum as well as some of the internal structure of the peat deposit, and thus to derive the total thickness of the peat deposit and (in some cases the thicknesses of its constituent layers. The first evaluation of the propagation velocity of electromagnetic waves in Azorean peat yielded a value of 0.04 m ns-1 for 100 MHz and 500 MHz radar antennae. For one of the study sites, the GPR data were analysed using GIS software to produce tridimensional models and thus to estimate the volumes of peat layers. This type of analysis has potential utility for quantifying some of the ecosystem services provided by peatlands.

  3. Inoculation of sphagnum-based soil substrate with entomopathogenic fungus Isaria fumosorosea (Hypocreales: Cordycipitaceae)

    Science.gov (United States)

    Zemek, Rostislav; Konopická, Jana; Bohatá, Andrea

    2018-04-01

    Convenient ecological alternative to broad-spectrum chemical pesticides is the utilization of natural enemies, like predators, parasitoids and microorganisms. A substantial number of microbial biopesticides based on entomopathogenic fungi have been developed worldwide since 1960s. Beauveria bassiana (Balsamo-Crivelli) Vuillemin, Metarhizium anisopliae (Metchnikoff) Sorokin, Isaria fumosorosea (Wize), and B. brongniartii (Saccardo) Petch are the most common species used in commercially produced mycopesticides. Besides direct biological pest control, these fungi could be also used in preventive application programs, particularly in ornamental or nursery plants to provide better control against pests. The aim of the present study was to investigate potential of pre-colonization of sphagnum-based soil substrate with I. fumosorosea strain CCM 8367 which was found earlier to be highly virulent against several pest species. We developed simple laboratory apparatus for application of fungal spore suspension into the substrate. Suspension was prepared from blastospores obtained by submerged cultivation on potato dextrose broth (PDB) medium using an orbital shaker. Inoculated substrate was placed into plastic bags and stored at constant temperature for six months. Every month, samples were analyzed for concentration of colony forming units (CFU) by elution and selective medium technique. The results showed that at 20°C the fungus successfully colonized the soil substrate and persisted there although the mean concentration slightly decreased from 5.89×104 to 2.76×104 CFU per milliliter of substrate during the experiment. Temperature 30°C had negative effect on survival of the fungus and is not recommended for long-term storage of pre-inoculated substrate. We can conclude that I. fumosorosea-colonized substrate can be convenient for preventive and permanent protection of various plants against soil-dwelling pests.

  4. CO2 and CH4 fluxes of contrasting pristine bogs in southern Patagonia (Tierra del Fuego, Argentina)

    Science.gov (United States)

    Münchberger, Wiebke; Blodau, Christian; Kleinebecker, Till; Pancotto, Veronica

    2015-04-01

    South Patagonian peatlands cover a wide range of the southern terrestrial area and thus are an important component of the terrestrial global carbon cycle. These extremely southern ecosystems have been accumulating organic material since the last glaciation up to now and are - in contrast to northern hemisphere bogs - virtually unaffected by human activities. So far, little attention has been given to these pristine ecosystems and great carbon reservoirs which will potentially be affected by climate change. We aim to fill the knowledge gap in the quantity of carbon released from these bogs and in what controls their fluxes. We study the temporal and spatial variability of carbon fluxes in two contrasting bog ecosystems in southern Patagonia, Tierra del Fuego. Sphagnum-dominated bog ecosystems in Tierra del Fuego are similar to the ones on the northern hemisphere, while cushion plant-dominated bogs can almost exclusively be found in southern Patagonia. These unique cushion plant-dominated bogs are found close to the coast and their occurrence changes gradually to Sphagnum-dominated bogs with increasing distance from the coast. We conduct closed chamber measurements and record relevant environmental variables for CO2 and CH4 fluxes during two austral vegetation periods from December to April. Chamber measurements are performed on microforms representing the main vegetation units of the studied bogs. Gas concentrations are measured with a fast analyzer (Los Gatos Ultraportable Greenhouse Gas Analyzer) allowing to accurately record CH4 fluxes in the ppm range. We present preliminary results of the carbon flux variability from south Patagonian peat bogs and give insights into their environmental controls. Carbon fluxes of these two bog types appear to be highly different. In contrast to Sphagnum-dominated bogs, cushion plant-dominated bogs release almost no CH4 while their CO2 flux in both, photosynthesis and respiration, can be twice as high as for Sphagnum

  5. Limitantes físicos y bióticos de la regeneración arbórea en matorrales sucesionales de la Isla Grande de Chiloé, Chile Physical and biotic constraints on tree regeneration in secondary shrublands of Chiloé Island, Chile

    Directory of Open Access Journals (Sweden)

    MARÍA F DÍAZ

    2007-03-01

    Full Text Available Los matorrales sucesionales establecidos después de la corta y quema de bosques son frecuentes en Chiloé y territorios continentales vecinos. Estos sitios son dominados por arbustos de Baccharis patagonica, musgos en cojín del género Sphagnum, plantas palustres y helechos. En estos sitios hemos registrado escasa o nula colonización arbórea (Successional shrublands created by clearcutting and burning of forests are frequent in Chiloé Island and surrounding mainland in southern Chile. These areas are characterized by seasonally waterlogged soils, and vegetation dominated by sedges, ferns and shrubs, such as Baccharis patagonica, with thick carpets of Sphagnum moss occupying the spaces between shrubs. Tree regeneration in these sites was shown to be sparse or completely lacking (< 0.3 seedlings m-2 compared with 7.2 seedlings m-2 in adjacent forests. Colonization of shade-intolerant, pioneer trees may be reduced underneath Baccharis due to crown shading and on top of Sphagnum cushions, because of unfavorable conditions for tree establishment, including low pH and soil water saturation. We evaluated differences in germination rates among pioneer tree species grown in an experimental soil moisture gradient. Seed germination percentage was low for Drimys winteri and Nothofagus nitida unrelated to humidity conditions but differed between substrates (moss vs. soil. Embothrium had higher germination and survivorship when growing on Sphagnum cushions. We also monitored seedling survival of two pioneer tree species (Embothrium coccineum and Drimys winteri transplanted directly under Baccharis shrubs, in open areas, or on moss patches. Even though survivorship of Embothrium and Drimys under Baccharis was < 40 %, in one of the study sites, there were no differences between treatments. Waterlogged soils would constraint tree regeneration on successional shrublands due to a lack of elevated substrates. However, the presence of Sphagnum cushions favors

  6. Estudio de las características del drenaje de un suelo orgánico del páramo de las papas, Cauca Study of characteristics of drainage conditions in an organic soil at paramo de las papas

    Directory of Open Access Journals (Sweden)

    Tafur Hermann Harold

    1990-12-01

    Full Text Available En la hacienda Los Andes, ubicada en el municipio de San Sebastián, departamento del Cauca, Colombia (2.700 m.s.n.m., se adelantó un estudio acerca de las características hidráulicas de sus suelos, determinados por un alto contenido de materia orgánica (suelos orgánicos. Se encontró que a pesar de la alta porosidad que puede presentar un suelo orgánico, su permeabilidad no necesariamente, responde directamente a esta característica, porque está dominada esencialmente por microporos. El mal drenaje de estos suelos (encharcamiento, está determinado por la alta capacidad de almacenamiento de agua de su vegetación natural, el musgo, el cual a su vez tiene baja transmisibilidad. Se describen los procesos mediante los cuales los agricultores adecuan los suelos para el uso agrícola.A study about the hydraulic characteristics of the organic soil in a farm located at Paramo de Las Papas (2700 m.a.s.l., Colombia, was carried out. It was found that permeability is not directly related with the high porosity of this type of soils. The present water logging is determined by the high water holding capacity of the surface vegetation, that is constitued by moss species, material that have a low transmisibility. In this paper, the proccess by which farmers reclaim the soils for cultivation, is described too.

  7. Dynamics of Viral Abundance and Diversity in a Sphagnum-Dominated Peatland: Temporal Fluctuations Prevail Over Habitat.

    Science.gov (United States)

    Ballaud, Flore; Dufresne, Alexis; Francez, André-Jean; Colombet, Jonathan; Sime-Ngando, Télesphore; Quaiser, Achim

    2015-01-01

    Viruses impact microbial activity and carbon cycling in various environments, but their diversity and ecological importance in Sphagnum-peatlands are unknown. Abundances of viral particles and prokaryotes were monitored bi-monthly at a fen and a bog at two different layers of the peat surface. Viral particle abundance ranged from 1.7 x 10(6) to 5.6 x 10(8) particles mL(-1), and did not differ between fen and bog but showed seasonal fluctuations. These fluctuations were positively correlated with prokaryote abundance and dissolved organic carbon, and negatively correlated with water-table height and dissolved oxygen. Using shotgun metagenomics we observed a shift in viral diversity between winter/spring and summer/autumn, indicating a seasonal succession of viral communities, mainly driven by weather-related environmental changes. Based on the seasonal asynchrony between viral and microbial diversity, we hypothesize a seasonal shift in the active microbial communities associated with a shift from lysogenic to lytic lifestyles. Our results suggest that temporal variations of environmental conditions rather than current habitat differences control the dynamics of virus-host interactions in Sphagnum-dominated peatlands.

  8. Sulphur, nitrogen and carbon content of Sphagnum capillifolium and Pseudevernia furfuracea exposed in bags in the Naples urban area

    International Nuclear Information System (INIS)

    Vingiani, S.; Adamo, P.; Giordano, S.

    2004-01-01

    The accumulation ability of the major elements sulphur, nitrogen and carbon by the moss Sphagnum capillifolium (Ehrh.) Hedw. and the lichen Pseudevernia furfuracea (L.) Zopf exposed in bags in Naples urban area,was investigated. Bags were exposed at the beginning of July 1999 and gathered in two subsequent moments: at the end of the dry season (after 10 weeks of exposure) and during the wet season (after 17 weeks of exposure), to include the effects of rainy conditions. Sulphur and N content of the lichen increased all over the exposure period, while the level of C did not change significantly either after 10 or 17 weeks of exposition. For the moss the S accumulation was limited to the dry period of exposure, whereas N and C content decreased with exposure. Results, in contrast with those obtained in a previous study on trace elements bioaccumulation [Adamo et al., Environmental Pollution, (2003) 122, 91-103], suggest that accumulation of gaseous pollutants is strongly influenced by biomonitor vitality and that lichen bags are a more reliable and effective tool for monitoring S, N and C atmospheric depositions in urban areas compared to moss bags, because of greater lichen resistance to dry and stressing conditions of urban environment. - The lichen Pseudevernia furfuracea is more effective than the moss Sphagnum capillifolium as S and N pollutants biomonitor

  9. Sphagnum mosses from 21 ombrotrophic bogs in the athabasca bituminous sands region show no significant atmospheric contamination of "heavy metals".

    Science.gov (United States)

    Shotyk, William; Belland, Rene; Duke, John; Kempter, Heike; Krachler, Michael; Noernberg, Tommy; Pelletier, Rick; Vile, Melanie A; Wieder, Kelman; Zaccone, Claudio; Zhang, Shuangquan

    2014-11-04

    Sphagnum moss was collected from 21 ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca bituminous sands in Alberta (AB). In comparison to contemporary Sphagnum moss from four bogs in rural locations of southern Germany (DE), the AB mosses yielded lower concentrations of Ag, Cd, Ni, Pb, Sb, and Tl, similar concentrations of Mo, but greater concentrations of Ba, Th, and V. Except for V, in comparison to the "cleanest", ancient peat samples ever tested from the northern hemisphere (ca. 6000-9000 years old), the concentrations of each of these metals in the AB mosses are within a factor of 3 of "natural, background" values. The concentrations of "heavy metals" in the mosses, however, are proportional to the concentration of Th (a conservative, lithophile element) and, therefore, contributed to the plants primarily in the form of mineral dust particles. Vanadium, the single most abundant trace metal in bitumen, is the only anomaly: in the AB mosses, V exceeds that of ancient peat by a factor of 6; it is therefore enriched in the mosses, relative to Th, by a factor of 2. In comparison to the surface layer of peat cores collected in recent years from across Canada, from British Columbia to New Brunswick, the Pb concentrations in the mosses from AB are far lower.

  10. Contrasting diversity of testate amoebae communities in Sphagnum and brown-moss dominated patches in relation to shell counts.

    Science.gov (United States)

    Lizoňová, Zuzana; Horsák, Michal

    2017-04-01

    Ecological studies of peatland testate amoebae are generally based on totals of 150 individuals per sample. However, the suitability of this standard has never been assessed for alkaline habitats such as spring fens. We explored the differences in testate amoeba diversity between Sphagnum and brown-moss microhabitats at a mire site with a highly diversified moss layer which reflects the small-scale heterogeneity in groundwater chemistry. Relationships between sampling efficiency and sample completeness were explored using individual-based species accumulation curves and the effort required to gain an extra species was assessed. Testate amoeba diversity differed substantially between microhabitats, with brown mosses hosting on average twice as many species and requiring greater shell totals to reach comparable sample analysis efficiency as for Sphagnum. Thus, for samples from alkaline conditions an increase in shell totals would be required and even an overall doubling up to 300 individuals might be considered for reliable community description. Our small-scale data are likely not robust enough to provide an ultimate solution for the optimization of shell totals. However, the results proved that testate amoebae communities from acidic and alkaline environments differ sharply in both species richness and composition and they might call for different methodological approaches. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. To what extent do food preferences explain the trophic position of heterotrophic and mixotrophic microbial consumers in a Sphagnum peatland?

    Science.gov (United States)

    Jassey, Vincent E J; Meyer, Caroline; Dupuy, Christine; Bernard, Nadine; Mitchell, Edward A D; Toussaint, Marie-Laure; Metian, Marc; Chatelain, Auriel P; Gilbert, Daniel

    2013-10-01

    Although microorganisms are the primary drivers of biogeochemical cycles, the structure and functioning of microbial food webs are poorly studied. This is the case in Sphagnum peatlands, where microbial communities play a key role in the global carbon cycle. Here, we explored the structure of the microbial food web from a Sphagnum peatland by analyzing (1) the density and biomass of different microbial functional groups, (2) the natural stable isotope (δ(13)C and δ(15)N) signatures of key microbial consumers (testate amoebae), and (3) the digestive vacuole contents of Hyalosphenia papilio, the dominant testate amoeba species in our system. Our results showed that the feeding type of testate amoeba species (bacterivory, algivory, or both) translates into their trophic position as assessed by isotopic signatures. Our study further demonstrates, for H. papilio, the energetic benefits of mixotrophy when the density of its preferential prey is low. Overall, our results show that testate amoebae occupy different trophic levels within the microbial food web, depending on their feeding behavior, the density of their food resources, and their metabolism (i.e., mixotrophy vs. heterotrophy). Combined analyses of predation, community structure, and stable isotopes now allow the structure of microbial food webs to be more completely described, which should lead to improved models of microbial community function.

  12. Origins, genetic structure, and systematics of the narrow endemic peatmosses (Sphagnum): S. guwassanense and S. triseriporum (Sphagnaceae).

    Science.gov (United States)

    Shaw, A Jonathan; Shaw, Blanka; Johnson, Matthew G; Higuchi, Masanobu; Arikawa, Tomotsugu; Ueno, Takeshi; Devos, Nicolas

    2013-06-01

    Sphagnum dominates vast expanses of wetland habitats throughout the northern hemisphere and species delimitation within the genus is important because floristic changes associated with a warming global climate may have measureable impacts on large-scale ecological processes. Most northern hemisphere peatmoss species (Sphagnum) have circumboreal ranges, but the Japanese species generally known as S. calymmatophyllum is endemic to Honshu Island. This prompted a population genetic and phylogenetic analysis to resolve the origin(s), population structure, and phylogenetic relationships of this morphologically variable species. • Sixty plants collected from Mt. Gassan and Mt. Hakkoda were genotyped for 12 microsatellite loci. Two plastid loci and three anonymous nuclear loci were sequenced in a subset of the plants, plus representatives from 10 closely related species. • Gametophytes exhibited fixed or nearly fixed heterozygosity at 9-10 of the 12 microsatellite loci. Two genetic groups were resolved by the microsatellite data, individuals showed no evidence of admixture, and the two groups of plants differ in morphology. They are heterozygous for different sets of alleles. The two taxa share plastid DNA sequences with two species that are common in Alaska. • Two taxa were distinguished: S. guwassanense and S. triseriporum. Both are allopolyploids; they originated independently from different but closely related progenitors. The maternal progenitor was likely either S. orientale or S. inexspectatum. The two allopolyploid taxa are heterozygous for (different) private microsatellite alleles, and one progenitor could be extinct.

  13. Nitrous oxide emission potentials of Burkholderia species isolated from the leaves of a boreal peat moss Sphagnum fuscum.

    Science.gov (United States)

    Nie, Yanxia; Li, Li; Wang, Mengcen; Tahvanainen, Teemu; Hashidoko, Yasuyuki

    2015-01-01

    Using a culture-based nitrous oxide (N2O) emission assay, three active N2O emitters were isolated from Sphagnum fuscum leaves and all identified as members of Burkholderia. These isolates showed N2O emission in the medium supplemented with [Formula: see text] but not with [Formula: see text], and Burkholderia sp. SF-E2 showed the most efficient N2O emission (0.20 μg·vial(-1)·day(-1)) at 1.0 mM KNO3. In Burkholderia sp. SF-E2, the optimum pH for N2O production was 5.0, close to that of the phyllosphere of Sphagnum mosses, while the optimum temperature was uniquely over 30 °C. The stimulating effect of additional 1.5 mM sucrose on N2O emission was ignorable, but Burkholderia sp. SF-E2 upon exposure to 100 mg·L(-1) E-caffeic acid showed uniquely 67-fold higher N2O emission. All of the three N2O emitters were negative in both acetylene inhibition assay and PCR assay for nosZ-detection, suggesting that N2O reductase or the gene itself is missing in the N2O-emitting Burkholderia.

  14. Mercury methylation in Sphagnum moss mats and its association with sulfate-reducing bacteria in an acidic Adirondack forest lake wetland.

    Science.gov (United States)

    Yu, Ri-Qing; Adatto, Isaac; Montesdeoca, Mario R; Driscoll, Charles T; Hines, Mark E; Barkay, Tamar

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum moss mat. Sphagnum, a bryophyte dominating boreal peatlands, and its associated microbial communities appear to play an important role in the production and accumulation of MeHg in high-latitude ecosystems. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  15. High specificity but contrasting biodiversity of Sphagnum-associated bacterial and plant communities in bog ecosystems independent of the geographical region.

    Science.gov (United States)

    Opelt, Katja; Berg, Christian; Schönmann, Susan; Eberl, Leo; Berg, Gabriele

    2007-10-01

    Mosses represent ecological niches that harbor a hitherto largely uncharacterized microbial diversity. To investigate which factors affect the biodiversity of bryophyte-associated bacteria, we analyzed the bacterial communities associated with two moss species, which exhibit different ecological behaviors and importance in bog ecosystems, Sphagnum magellanicum and Sphagnum fallax, from six temperate and boreal bogs in Germany and Norway. Furthermore, their surrounding plant communities were studied. Molecular analysis of bacterial communities was determined by single-strand conformation polymorphism (SSCP) analysis using eubacterial and genus-specific primers for the dominant genera Burkholderia and Serratia as well as by sequence analysis of a Burkholderia 16S rRNA gene clone library. Plant communities were analyzed by monitoring the abundance and composition of bryophyte and vascular plant species, and by determining ecological indicator values. Interestingly, we found a high degree of host specificity for associated bacterial and plant communities of both Sphagnum species independent of the geographical region. Calculation of diversity indices on the basis of SSCP gels showed that the S. fallax-associated communities displayed a statistically significant higher degree of diversity than those associated with S. magellanicum. In contrast, analyses of plant communities of Sphagnum-specific habitats resulted in a higher diversity of S. magellanicum-specific habitats for all six sites. The higher content of nutrients in the S. fallax-associated ecosystems can explain higher diversity of microorganisms.

  16. The Roles of Sphagnum and Cyperaceae in the Methane Cycle of an Ombrotrophic Bog Revealed by the Carbon Isotope Ratios of Leaf Waxes

    Science.gov (United States)

    Isles, P. D.; Nichols, J. E.; Peteet, D. M.; Kenna, T. C.

    2011-12-01

    Methane is a strong greenhouse gas, and the role of the terrestrial carbon cycle in the concentrations of atmospheric methane is poorly understood. What is clear, is that northern peatlands are a significant source of methane to the atmosphere. A recent discovery, and a topic of much scrutiny, has been the relationship between Sphagnum in peatlands and symbiotic methanotrophic bacteria. These bacteria oxidize methane produced at depth in peatlands before it is released to the atmosphere, contributing 13C-depleted CO2 to Sphagnum photosynthate. We seek to better understand the fate of methane produced in peatlands at depth, and the relationship between methane release from peatland surfaces and parameters such as temperature, moisture, and vegetation type. We compare carbon isotope ratios of leaf wax n-alkanes from sphagnum and vascular plants and major element chemistry at three different microhabitats, hummock, hollow, and sedge tussock, in Mer Bleue an ombrotrophic peatland near Ottowa, Ontario, Canada. We use these compound-specific carbon isotope measurements to constrain the amount of methane-derived CO2 incorporated by Sphagnum. We also compare our multiannually resolved down-core measurements to data from long-term monitoring of climate parameters and methane flux from the same microhabitats to ground-truth our sedimentary signature of methane with instrumental measurements.

  17. Freezing cytorrhysis and critical temperature thresholds for photosystem II in the peat moss Sphagnum capillifolium.

    Science.gov (United States)

    Buchner, Othmar; Neuner, Gilbert

    2010-07-01

    Leaflets of Sphagnum capillifolium were exposed to temperatures from -5 degrees C to +60 degrees C under controlled conditions while mounted on a microscope stage. The resultant cytological response to these temperature treatments was successfully monitored using a light and fluorescence microscope. In addition to the observable cytological changes during freezing cytorrhysis and heat exposure on the leaflets, the concomitant critical temperature thresholds for inactivation of photosystem II (PS II) were studied using a micro fibre optic and a chlorophyll fluorometer mounted to the microscope stage. Chlorophyllous cells of S. capillifolium showed extended freezing cytorrhysis immediately after ice nucleation at -1.1 degrees C in the water in which the leaflets were submersed during the measurement. The occurrence of freezing cytorrhysis, which was visually manifested by cell shrinkage, was highly dynamic and was completed within 2 s. A total reduction of the mean projected diameter of the chloroplast containing area during freezing cytorrhysis from 8.9 to 3.8 microm indicates a cell volume reduction of approximately -82%. Simultaneous measurement of chlorophyll fluorescence of PS II was possible even through the frozen water in which the leaf samples were submersed. Freezing cytorrhysis was accompanied by a sudden rise of basic chlorophyll fluorescence. The critical freezing temperature threshold of PS II was identical to the ice nucleation temperature (-1.1 degrees C). This is significantly above the temperature threshold at which frost damage to S. capillifolium leaflets occurs (-16.1 degrees C; LT(50)) which is higher than observed in most higher plants from the European Alps during summer. High temperature thresholds of PS II were 44.5 degrees C which is significantly below the heat tolerance of chlorophyllous cells (49.9 degrees C; LT(50)). It is demonstrated that light and fluorescence microscopic techniques combined with simultaneous chlorophyll fluorescence

  18. Active Sphagnum girgensohnii Russow Moss Biomonitoring of an Industrial Site in Romania: Temporal Variation in the Elemental Content.

    Science.gov (United States)

    Culicov, Otilia A; Zinicovscaia, Inga; Duliu, O G

    2016-05-01

    The moss-bag transplant technique was used to investigate the kinetics of the accumulation of 38 elements in Sphagnum girgensohni moss samples in the highly polluted municipality of Baia Mare, Romania. The moss samples collected from the unpolluted Vitosha Mountain Natural Reserve, Bulgaria, were analyzed after 1, 2, 3, and 4 months of exposure, respectively. The ANOVA method was used to assay the statistical significance of the observed changes in elemental content, as determined by neutron activation analysis. The content of Zn, Se, As, Ag, Cd, and Sb increased steadily, while that of physiologically active K and Cl, as well as Rb and Cs, decreased exponentially. The study showed that an adequate application of the moss transplant technique in an urban environment should consider the exposure time as a critical parameter, since particular elements are depleted in the moss at sites with high atmospheric loading of metals.

  19. Allo-allo-triploid Sphagnum × falcatulum: single individuals contain most of the Holantarctic diversity for ancestrally indicative markers.

    Science.gov (United States)

    Karlin, Eric F; Smouse, Peter E

    2017-08-01

    Allopolyploids exhibit both different levels and different patterns of genetic variation than are typical of diploids. However, scant attention has been given to the partitioning of allelic information and diversity in allopolyploids, particularly that among homeologous monoploid components of the hologenome. Sphagnum × falcatulum is a double allopolyploid peat moss that spans a considerable portion of the Holantarctic. With monoploid genomes from three ancestral species, this organism exhibits a complex evolutionary history involving serial inter-subgeneric allopolyploidizations. Studying populations from three disjunct regions [South Island (New Zealand); Tierra de Fuego archipelago (Chile, Argentina); Tasmania (Australia)], allelic information for five highly stable microsatellite markers that differed among the three (ancestral) monoploid genomes was examined. Using Shannon information and diversity measures, the holoploid information, as well as the information within and among the three component monoploid genomes, was partitioned into separate components for individuals within and among populations and regions, and those information components were then converted into corresponding diversity measures. The majority (76 %) of alleles detected across these five markers are most likely to have been captured by hybridization, but the information within each of the three monoploid genomes varied, suggesting a history of recurrent allopolyploidization between ancestral species containing different levels of genetic diversity. Information within individuals, equivalent to the information among monoploid genomes (for this dataset), was relatively stable, and represented 83 % of the grand total information across the Holantarctic, with both inter-regional and inter-population diversification each accounting for about 5 % of the total information. Sphagnum × falcatulum probably inherited the great majority of its genetic diversity at these markers by reticulation

  20. Denitrification at two nitrogen-polluted, ombrotrophic Sphagnum bogs in Central Europe: Insights from porewater N2O-isotope profiles

    Czech Academy of Sciences Publication Activity Database

    Novák, M.; Gebauer, G.; Thoma, M.; Curik, J.; Štěpánová, M.; Jacková, I.; Buzek, F.; Bárta, J.; Santrucková, H.; Fottová, D.; Kuběna, Aleš Antonín

    2015-01-01

    Roč. 81, č. 1 (2015), s. 48-57 ISSN 0038-0717 Grant - others:GA ČR(CZ) GAP504/12/1782 Institutional support: RVO:67985556 Keywords : Denitrification * Nitrogen isotopes * Nitrous oxide * Ombrotrophic bog * Porewater * Sphagnum * Wetland * Engineering controlled terms * Meteorological problems Subject RIV: DD - Geochemistry Impact factor: 4.152, year: 2015 http://library.utia.cas.cz/separaty/2015/E/kubena-0439538.pdf

  1. Abundant Trimethylornithine Lipids and Specific Gene Sequences Are Indicative of Planctomycete Importance at the Oxic/Anoxic Interface in Sphagnum-Dominated Northern Wetlands.

    Science.gov (United States)

    Moore, Eli K; Villanueva, Laura; Hopmans, Ellen C; Rijpstra, W Irene C; Mets, Anchelique; Dedysh, Svetlana N; Sinninghe Damsté, Jaap S

    2015-09-01

    Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses. Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine (TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomycete isolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) and molecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) in order to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout the profiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundance of planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliated with the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group. Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoye peat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mosse peat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundant TMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest that planctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and the change in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redox conditions at the oxic/anoxic interface. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. The distribution of {sup 137}Cs, K, Rb and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Vinichuk, M., E-mail: mykhailo.vinichuk@mark.slu.s [Department of Soil and Environment, Swedish University of Agricultural Sciences, SLU, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Department of Ecology, Zhytomyr State Technological University, 103 Chernyakhovsky Street, 10005 Zhytomyr (Ukraine); Johanson, K.J. [Department of Soil and Environment, Swedish University of Agricultural Sciences, SLU, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Rydin, H. [Department of Plant Ecology, Evolutionary Biology Centre, Uppsala University, Norbyvaegen 18D, SE-752 36 Uppsala (Sweden); Rosen, K. [Department of Soil and Environment, Swedish University of Agricultural Sciences, SLU, P.O. Box 7014, SE-750 07 Uppsala (Sweden)

    2010-02-15

    We record the distribution of {sup 137}Cs, K, Rb and Cs within individual Sphagnum plants (down to 20 cm depth) as well as {sup 137}Cs in vascular plants growing on a peatland in eastern central Sweden. In Calluna vulgaris{sup 137}Cs was mainly located within the green parts, whereas Andromeda polifolia, Eriophorum vaginatum and Vaccinium oxycoccos showed higher {sup 137}Cs activity in roots. Carex rostrata and Menyanthes trifoliata showed variable distribution of {sup 137}Cs within the plants. The patterns of {sup 137}Cs activity concentration distribution as well as K, Rb and Cs concentrations within individual Sphagnum plants were rather similar and were usually highest in the capitula and/or in the subapical segments and lowest in the lower dead segments, which suggests continuous relocation of those elements to the actively growing apical part. The {sup 137}Cs and K showed relatively weak correlations, especially in capitula and living green segments (0-10 cm) of the plant (r = 0.50). The strongest correlations were revealed between {sup 137}Cs and Rb (r = 0.89), and between {sup 137}Cs and stable Cs (r = 0.84). This suggests similarities between {sup 137}Cs and Rb in uptake and relocation within the Sphagnum, but that {sup 137}Cs differs from K.

  3. The distribution of 137Cs, K, Rb and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden

    International Nuclear Information System (INIS)

    Vinichuk, M.; Johanson, K.J.; Rydin, H.; Rosen, K.

    2010-01-01

    We record the distribution of 137 Cs, K, Rb and Cs within individual Sphagnum plants (down to 20 cm depth) as well as 137 Cs in vascular plants growing on a peatland in eastern central Sweden. In Calluna vulgaris 137 Cs was mainly located within the green parts, whereas Andromeda polifolia, Eriophorum vaginatum and Vaccinium oxycoccos showed higher 137 Cs activity in roots. Carex rostrata and Menyanthes trifoliata showed variable distribution of 137 Cs within the plants. The patterns of 137 Cs activity concentration distribution as well as K, Rb and Cs concentrations within individual Sphagnum plants were rather similar and were usually highest in the capitula and/or in the subapical segments and lowest in the lower dead segments, which suggests continuous relocation of those elements to the actively growing apical part. The 137 Cs and K showed relatively weak correlations, especially in capitula and living green segments (0-10 cm) of the plant (r = 0.50). The strongest correlations were revealed between 137 Cs and Rb (r = 0.89), and between 137 Cs and stable Cs (r = 0.84). This suggests similarities between 137 Cs and Rb in uptake and relocation within the Sphagnum, but that 137 Cs differs from K.

  4. Yeast communities in Sphagnum phyllosphere along the temperature-moisture ecocline in the boreal forest-swamp ecosystem and description of Candida sphagnicola sp. nov.

    Science.gov (United States)

    Kachalkin, Aleksey V; Yurkov, Andrey M

    2012-06-01

    The effects of the temperature-moisture factors on the phylloplane yeast communities inhabiting Sphagnum mosses were studied along the transition from a boreal forest to a swamp biotope at the Central Forest State Biosphere Reserve (Tver region, Russia). We tested the hypothesis that microclimatic parameters affect yeast community composition and structure even on a rather small spatial scale. Using a conventional plating technique we isolated and identified by molecular methods a total of 15 species of yeasts. Total yeast counts and species richness values did not depend on environmental factors, although yeast community composition and structure did. On average, Sphagnum in the swamp biotope supported a more evenly structured yeast community. Relative abundance of ascomycetous yeasts was significantly higher on swamp moss. Rhodotorula mucilaginosa dominated in the spruce forest and Cryptococcus magnus was more abundant in the swamp. Our study confirmed the low occurrence of tremellaceous yeasts in the Sphagnum phyllosphere. Of the few isolated ascomycetous yeast and yeast-like species, some were differentiated from hitherto known species in physiological tests and phylogenetic analyses. We describe one of them as Candida sphagnicola and designate KBP Y-3887(T) (=CBS 11774(T) = VKPM Y-3566(T) = MUCL 53590(T)) as the type strain. The new species was registered in MycoBank under MB 563443.

  5. The distribution of (137)Cs, K, Rb and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden.

    Science.gov (United States)

    Vinichuk, M; Johanson, K J; Rydin, H; Rosén, K

    2010-02-01

    We record the distribution of (137)Cs, K, Rb and Cs within individual Sphagnum plants (down to 20cm depth) as well as (137)Cs in vascular plants growing on a peatland in eastern central Sweden. In Calluna vulgaris(137)Cs was mainly located within the green parts, whereas Andromeda polifolia, Eriophorum vaginatum and Vaccinium oxycoccos showed higher (137)Cs activity in roots. Carex rostrata and Menyanthes trifoliata showed variable distribution of (137)Cs within the plants. The patterns of (137)Cs activity concentration distribution as well as K, Rb and Cs concentrations within individual Sphagnum plants were rather similar and were usually highest in the capitula and/or in the subapical segments and lowest in the lower dead segments, which suggests continuous relocation of those elements to the actively growing apical part. The (137)Cs and K showed relatively weak correlations, especially in capitula and living green segments (0-10cm) of the plant (r=0.50). The strongest correlations were revealed between (137)Cs and Rb (r=0.89), and between (137)Cs and stable Cs (r=0.84). This suggests similarities between (137)Cs and Rb in uptake and relocation within the Sphagnum, but that (137)Cs differs from K. Copyright 2009 Elsevier Ltd. All rights reserved.

  6. Flourish or flush: effects of simulated extreme rainfall events on Sphagnum-dwelling testate amoebae in a subarctic bog (Abisko, Sweden).

    Science.gov (United States)

    Tsyganov, Andrey N; Keuper, Frida; Aerts, Rien; Beyens, Louis

    2013-01-01

    Extreme precipitation events are recognised as important drivers of ecosystem responses to climate change and can considerably affect high-latitude ombrotrophic bogs. Therefore, understanding the relationships between increased rainfall and the biotic components of these ecosystems is necessary for an estimation of climate change impacts. We studied overall effects of increased magnitude, intensity and frequency of rainfall on assemblages of Sphagnum-dwelling testate amoebae in a field climate manipulation experiment located in a relatively dry subarctic bog (Abisko, Sweden). The effects of the treatment were estimated using abundance, species diversity and structure of living and empty shell assemblages of testate amoebae in living and decaying layers of Sphagnum. Our results show that increased rainfall reduced the mean abundance and species richness of living testate amoebae. Besides, the treatment affected species structure of both living and empty shell assemblages, reducing proportions of hydrophilous species. The effects are counterintuitive as increased precipitation-related substrate moisture was expected to have opposite effects on testate amoeba assemblages in relatively dry biotopes. Therefore, we conclude that other rainfall-related factors such as increased infiltration rates and frequency of environmental disturbances can also affect testate amoeba assemblages in Sphagnum and that hydrophilous species are particularly sensitive to variation in these environmental variables.

  7. Peces del Noroeste del Ecuador

    OpenAIRE

    Barriga, Ramiro

    1994-01-01

    La ictiofauna del occidente del Ecuador es poco conocida. Los peces del noroccidente son diferentes a los del suroccidente del Ecuador. 34 familias y 82 especies fueron colectadas que equivale al 11 % de las especies de peces continentales registradas en el Ecuador. Icteogeográficamente se sabe que la costa ecuatoriana posee dos provincias: la del Pacifico Norte y la del Guayas, se determinó que el límite de las dos provincias es el río Santiago ya que las especies del mencionado río so...

  8. Ebullition, Plant-Mediated Transport, and Subsurface Horizontal Water Flow Dominate Methane Transport in an Arctic Sphagnum Bog

    Science.gov (United States)

    Wehr, R. A.; McCalley, C. K.; Logan, T. A.; Chanton, J.; Crill, P. M.; Rich, V. I.; Saleska, S. R.

    2017-12-01

    Emission of the greenhouse gas methane from wetlands is of prime concern in the prediction of climate change - especially emission associated with thawing permafrost, which may drive a positive feedback loop of emission and warming. In addition to the biochemistry of methane production and consumption, wetland methane emission depends critically on the transport mechanisms by which methane moves through and out of the ecosystem. We therefore developed a model of methane biochemistry and transport for a sphagnum bog representing an intermediate permafrost thaw stage in Stordalen Mire, Sweden. In order to simultaneously reproduce measured profiles of both the concentrations and isotopic compositions of both methane and carbon dioxide in the peat pore water (Fig. 1) - as well as the surface methane emission - it was necessary for the model to include ebullition, plant-mediated transport via aerenchyma, and subsurface horizontal water flow. Diffusion of gas through the pore water was relatively unimportant. As a result, 90% of the produced methane escaped the wetland rather than being consumed by methanotrophic organisms in the near-surface pore water. Our model provides a comprehensive picture of methane emission from this bog site by quantifying the vertical profiles of: acetoclastic methanogenesis, hydrogenotrophic methanogenesis, methane oxidation, aerobic respiration, ebullition, plant-mediated transport, subsurface horizontal water flow, and diffusion.

  9. Microform-related community patterns of methane-cycling microbes in boreal Sphagnum bogs are site specific.

    Science.gov (United States)

    Juottonen, Heli; Kotiaho, Mirkka; Robinson, Devin; Merilä, Päivi; Fritze, Hannu; Tuittila, Eeva-Stiina

    2015-09-01

    Vegetation and water table are important regulators of methane emission in peatlands. Microform variation encompasses these factors in small-scale topographic gradients of dry hummocks, intermediate lawns and wet hollows. We examined methane production and oxidization among microforms in four boreal bogs that showed more variation of vegetation within a bog with microform than between the bogs. Potential methane production was low and differed among bogs but not consistently with microform. Methane oxidation followed water table position with microform, showing higher rates closer to surface in lawns and hollows than in hummocks. Methanogen community, analysed by mcrA terminal restriction fragment length polymorphism and dominated by Methanoregulaceae or 'Methanoflorentaceae', varied strongly with bog. The extent of microform-related variation of methanogens depended on the bog. Methanotrophs identified as Methylocystis spp. in pmoA denaturing gradient gel electrophoresis similarly showed effect of bog, and microform patterns were stronger within individual bogs. Our results suggest that methane-cycling microbes in boreal Sphagnum bogs with seemingly uniform environmental conditions may show strong site-dependent variation. The bog-intrinsic factor may be related to carbon availability but contrary to expectations appears to be unrelated to current surface vegetation, calling attention to the origin of carbon substrates for microbes in bogs. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. The rare peat moss Sphagnum wulfianum (Sphagnaceae) did not survive the last glacial period in northern European refugia.

    Science.gov (United States)

    Kyrkjeeide, Magni Olsen; Hassel, Kristian; Flatberg, Kjell I; Stenøien, Hans K

    2012-04-01

    Organisms may survive unfavorable conditions either by moving to more favorable areas by means of dispersal or by adapting to stressful environments. Pleistocene glacial periods represent extremely unfavorable conditions for the majority of life forms, especially sessile organisms. Many studies have revealed placements of refugial areas and postglacial colonization patterns of seed plants, but little is still known about areas of long-term survival and historical migration routes of bryophytes. Given overall differences in stress tolerance between seed plants and bryophytes, it is of interest to know whether bryophytes have survived periods of extreme climatic conditions better then seed plants in northern areas. The haploid and rarely spore-producing peat moss Sphagnum wulfianum is mostly found in areas that were covered by ice during the last glacial maximum. Twelve microsatellite markers were amplified from 43 populations (367 shoots) of this species, and data were analyzed using population genetic diversity statistics, Bayesian clustering methods, and coalescence-based inference tools to estimate historical and demographic parameters. Genetic diversity within populations was low, but populations were highly differentiated, with two main genetic clusters being recognized. The two main genetic groups have diverged quite recently in the Holocene, and the pattern of genetic variability and structuring gives no support for survival in Scandinavian refugia during the last glacial period in this species. The dispersal ability of this plant thus seems surprisingly high despite its infrequent spore production.

  11. Genotoxic effect of Pb and Cd on in vitro cultures of Sphagnum palustre: An evaluation by ISSR markers.

    Science.gov (United States)

    Sorrentino, Maria Cristina; Capozzi, Fiore; Giordano, Simonetta; Spagnuolo, Valeria

    2017-08-01

    In the present work, the genotoxic effect of cadmium and lead supplied in a laboratory trial, was investigated for the first time in the moss Sphagnum palustre, by ISSR molecular markers. A total of 169 reproducible bands were obtained with 12 primers, ten of which gave polymorphisms (i.e., appearance/disappearance of bands), indicating a clear genotoxic effect induced by the metals. Both metals induced a decrease of the genome template stability in a dose dependent manner. At concentration >10 -5 Cd also induced a general toxic effect in S. palustre, leading to chlorophyll degradation and moss death. Moreover, we followed the fate of supplied heavy metals into the moss tissue by SEM-EDX to see if they entered the cells. SEM-EDX observations on moss cultures treated with equimolar concentrations of the two metals showed that most Pb precipitated in form of particles on moss surface, while Cd did not aggregate in particles and was not found on moss surface. In light of these findings, we concluded that probably Pb induced a genotoxic effect at lower intracellular concentrations than Cd. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Project CLIMPEAT - Influence of global warming and drought on the carbon sequestration and biodiversity of Sphagnum peatlands

    Science.gov (United States)

    Lamentowicz, M.; Buttler, A.; Mitchell, E. A. D.; Chojnicki, B.; Słowińska, S.; Słowiński, M.

    2012-04-01

    Northern peatlands represent a globally significant pool of carbon and are subject to the highest rates of climate warming, and most of these peatlands are in continental settings. However, it is unclear if how fast peatlands respond to past and present changes in temperature and surface moisture in continental vs. oceanic climate settings. The CLIMPEAT project brings together scientists from Poland and Switzerland. Our goal is to assess the past and present vulnerability to climate change of Sphagnum peatland plant and microbial communities, peat organic matter transformations and carbon sequestration using a combination of field and mesocosm experiments simulating warming and water table changes and palaeoecological studies. Warming will be achieved using ITEX-type "Open-Top Chambers". The field studies are conducted in Poland, at the limit between oceanic and continental climates, and are part of a network of projects also including field experiments in the French Jura (sub-oceanic) and in Siberia (continental). We will calibrate the response of key biological (plants, testate amoebae) and geochemical (isotopic composition of organic compounds, organic matter changes) proxies to warming and water table changes and use these proxies to reconstruct climate changes during the last 1000 years.

  13. Mires and mire types of Peninsula Mitre, Tierra del Fuego, Argentina

    Directory of Open Access Journals (Sweden)

    A. Grootjans

    2014-01-01

    Full Text Available In 2007, a field visit by members of the International Mire Conservation Group (IMCG to the Atlantic coast of Peninsula Mitre (the easternmost part of Isla Grande de Tierra del Fuego, Argentina gathered information on mire diversity in this remote wild area with largely pristine mires. Our expedition showed that Peninsula Mitre hosts a wide variety of habitats across two exciting ecological gradients: (i a regional west–east gradient from Sphagnum magellanicum dominated mires in the west to Astelia pumila dominated mires in the east; and (ii a gradient from extremely acid to extremely carbonate rich mire types induced by local bedrock. The large variety of hydromorphological mire types comprises raised bogs, blanket bogs, sloping fens, string fens, flat fens and calcareous spring fens. In the Atlantic coastal area, the abundance of Sphagnum magellanicum in the ombrogenic systems decreases conspicuously from west to east with the species being almost absent in the east. However, the fossil record shows thick layers of Sphagnum peat close beneath mire surfaces everywhere, indicating that substantial hydrological and ecological changes have taken place in the recent past. We observed large scale erosion in the mires along the Atlantic coast. Locally, well-developed fen systems are present, including calcareous spring fens with active travertine (tufa deposition. The regional vegetation can be regarded as a parallel to that of boreal oceanic regions in the northern hemisphere. The mires and peatlands of the peninsula are of global significance. They are impressive, peculiar, extensive and largely pristine mires in a globally very rare climatic and biogeographical context embedded in a landscape with significant natural dynamics. The damaging impact of free-roaming cattle on the mires and upland vegetation is, however, conspicuous and needs urgent attention. Peninsula Mitre deserves the highest possible protection, e.g. as a provincial protected

  14. Growing season variability of net ecosystem CO2 exchange and evapotranspiration of a sphagnum mire in the broad-leaved forest zone of European Russia

    International Nuclear Information System (INIS)

    Olchev, A; Volkova, E; Karataeva, T; Novenko, E

    2013-01-01

    The spatial and temporal variability of net ecosystem exchange (NEE) of CO 2 and evapotranspiration (ET) of a karst-hole sphagnum peat mire situated at the boundary between broad-leaved and forest–steppe zones in the central part of European Russia in the Tula region was described using results from field measurements. NEE and ET were measured using a portable measuring system consisting of a transparent ventilated chamber combined with an infrared CO 2 /H 2 O analyzer, LI-840A (Li-Cor, USA) along a transect from the southern peripheral part of the mire to its center under sunny clear-sky weather conditions in the period from May to September of 2012 and in May 2013. The results of the field measurements showed significant spatial and temporal variability of NEE and ET that was mainly influenced by incoming solar radiation and ground water level. The seasonal patterns of NEE and ET within the mire were quite different. During the entire growing season the central part of the mire was a sink of CO 2 for the atmosphere. NEE reached maximal values in June–July (−6.8 ± 4.2 μmol m −2 s −1 ). The southern peripheral part of the mire, due to strong shading by the surrounding forest, was a sink of CO 2 for the atmosphere in June–July only. ET reached maximal values in the well-lighted central parts of the mire in May (0.34 ± 0.20 mm h −1 ) mainly because of high air and surface temperatures and the very wet upper peat horizon and sphagnum moss. Herbaceous species made the maximum contribution to the total gross primary production (GPP) in both the central and the peripheral parts of the mire. The contribution of sphagnum to the total GPP of these plant communities was relatively small and ranged on sunny days of July–August from −1.1 ± 1.1 mgC g −1 of dry weight (DW) per hour in the peripheral zone of the mire to −0.6 ± 0.2 mgC g −1 DW h −1 at the mire center. The sphagnum layer made the maximum contribution to total ET at the mire center (0

  15. The use of Sphagnum recurvum Pal. Beauv. as biological tests for determination of the level of pollution with fluorine compounds and sulphur dioxide in the environment

    Directory of Open Access Journals (Sweden)

    Maria Świeboda

    2014-01-01

    Full Text Available The green parts of the peat moss Sphagnum recurvum Pal. Beauv. were used as a biological test to evaluate the pollution level of the natural environment in the region of the aluminium works "Skawina" (Southern Poland with fluorine compounds and sulphur dioxide. The moss samples were placed in nylon nets and exposed to the polluted air for 6 weeks, then the fluorine and sulphur content in them was determined. The results demonstrated the usefulness of this method for the purpose of establishing the range of influence of the emitted industrial pollution.

  16. DNA molecular markers in mosses and their use for the characterization of a Sphagnum palustre clone, for its exploitation as a passive contaminant sensor

    OpenAIRE

    Crespo Pardo, David

    2015-01-01

    The control of the air quality is often assessed by the use of terrestrial mosses. However, due to the lack of standardization in the used techniques, the comparison between the available studies is difficult. My PhD thesis was related to the European project FP7-Mossclone. The aim of this project is the development of a standardized method for biomonitoring the level of atmospheric pollution through the use of a devitalized moss clone of Sphagnum palustre, using the moss bags technique. My p...

  17. Methylocapsa acidiphila gen. nov., sp. nov., a novel methane-oxidizing and dinitrogen-fixing acidophilic bacterium from Sphagnum bog.

    Science.gov (United States)

    Dedysh, Svetlana N; Khmelenina, Valentina N; Suzina, Natalia E; Trotsenko, Yuri A; Semrau, Jeremy D; Liesack, Werner; Tiedje, James M

    2002-01-01

    A novel genus and species, Methylocapsa acidiphila gen. nov., sp. nov., are proposed for a methane-oxidizing bacterium isolated from an acidic Sphagnum peat bog. This bacterium, designated strain B2T, represents aerobic, gram-negative, colourless, non-motile, curved coccoids that form conglomerates covered by an extracellular polysaccharide matrix. The cells use methane and methanol as sole sources of carbon and energy and utilize the serine pathway for carbon assimilation. Strain B2T is a moderately acidophilic organism with growth between pH 4.2 and 7.2 and at temperatures from 10 to 30 degrees C. The cells possess a well-developed system of intracytoplasmic membranes (ICM) packed in parallel on only one side of the cell membrane. This type of ICM structure represents a novel arrangement, which was termed type III. The resting cells are Azotobacter-type cysts. Strain B2T is capable of atmospheric nitrogen fixation; it possesses particulate methane monooxygenase and does not express soluble methane monooxygenase. The major phospholipid fatty acid is 18:1omega7c and the major phospholipids are phosphatidylglycerols. The G+C content of the DNA is 63.1 mol%. This bacterium belongs to the alpha-subclass of the Proteobacteria and is most closely related to the acidophilic methanotroph Methylocella palustris KT (97.3% 16S rDNA sequence similarity). However, the DNA-DNA hybridization value between strain B2T and Methylocella palustris K(T) is only 7%. Thus, strain B2T is proposed to comprise a novel genus and species, Methylocapsa acidiphila gen. nov., sp. nov. Strain B2T (= DSM 13967T = NCIMB 13765T) is the type strain.

  18. Changes in the aquatic moss Sphagnum denticulatum Brid. population abundance in a softwater lake over a period of three years

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    Józef Szmeja

    2011-01-01

    Full Text Available Changes in population abundance of submerged Sphagnum denticulatum Brid. were studied in an acidic and oligotrophic lake in NW Poland over three years. Individuals were counted in a moss carpet at a depth of 2.5 m on 4 experimental plots, 1 × 1 m each, every 30 days for 36 months using the SCUBA method. PAR intensity was seasonally variable (in winter higher than in summer. Changes in water pH, conductivity, HCO3- concentration, hydration and sediment pH were statistically insignificant (p > 0.05. In the summer of the second study year the moss carpet disappeared almost completely due to a massive bloom of filamentous green algae. Periods of growth, regression and regeneration were observed in the population. The stabilisation of population size took 24 months and followed the pattern: slight fluctuations, then rapid growth and repetition of slight fluctuations. The first stage lasted nine, the second four and the third nine months. These stages took place irrespective of seasons, temperature or PAR intensity. Each rapid increase in abundance lasted about 30 days, at PAR intensity >20% and water temperature ranging from 11 to 16oC (in winter, spring or autumn. The regression stage brought about by the algal bloom started in the second year (in summer and lasted six months (until the end of January in the third year. The population regeneration began in winter (in February, water temperature 3.0oC, PAR about 20%, ice cover 0.15 m and finished with the end of spring. The population of S. denticulatum shows a repetitive pattern of abundance variations, which is seriously disturbed in summer, especially after a warm spring, by a massive bloom of filamentous green algae.

  19. Isotope composition of bulk carbon in replicated Sphagnum peat cores from three central European high-elevation wetlands

    International Nuclear Information System (INIS)

    Novak, Martin; Zemanova, Leona; Jackova, Iva; Buzek, Frantisek; Adamova, Marie

    2009-01-01

    Several processes may contribute to systematic downcore trends in δ 13 C of bulk Sphagnum peat. Whereas changes in water availability during C assimilation may change δ 13 C values in both a negative and positive direction, other processes would always cause a uni-directional shift in δ 13 C. Selective preservation of isotopically light lignin C may lead to more negative δ 13 C values with an increasing depth and age of peat. Anthropogenic change toward lower δ 13 C of atmospheric CO 2 due to massive coal burning since the beginning of the Industrial Revolution would result in lower δ 13 C of the youngest past layers, and in higher δ 13 C of older peat layers. Emissions of low-δ 13 C methane from wetlands should result in a progressive enrichment of the residual peat substrate in the heavier isotope 13 C. Consequently, deeper peat would have higher δ 13 C. In a specific peat profile, the downcore trend in δ 13 C will be the result of an interplay between all these isotope-sensitive processes. Most Central European wetlands studied previously show a 13 C enrichment (i.e., higher δ 13 C values) with an increasing depth and age. Here we focus on sites which showed lower δ 13 C with an increasing depth and age when a single peat core was taken. Replication did not confirm this negative downcore δ 13 C shift. A positive downcore δ 13 C shift is more widespread than previously believed. We suggest that decreasing δ 13 C of atmospheric CO 2 and emissions of low-δ 13 C methane belong to the main controls of the downcore δ 13 C trends in young peat substrate. (author)

  20. Singulisphaera rosea sp. nov., a planctomycete from acidic Sphagnum peat, and emended description of the genus Singulisphaera.

    Science.gov (United States)

    Kulichevskaya, Irina S; Detkova, Ekaterina N; Bodelier, Paul L E; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; Dedysh, Svetlana N

    2012-01-01

    An aerobic, pink-pigmented, budding bacterium, designated strain S26(T), was isolated from an acidic Sphagnum peat bog of north-western Russia. Cells were non-motile and spherical, occurring singly, in pairs or in short chains, and were able to attach to surfaces by means of a holdfast material. Strain S26(T) was a moderately acidophilic, mesophilic organism capable of growth at pH 3.2-7.1 (optimum at pH 4.8-5.0) and at 4-33 °C (optimum at 20-26 °C). Most sugars, several organic acids and polyalcohols were the preferred growth substrates. The major fatty acids were C(16:0), C(18:1)ω9c and C(18:2)ω6c,12c. The major neutral lipids were n-C(31:9) hydrocarbon and squalene; the polar lipids were phosphatidylglycerol, phosphatidylcholine and components with an unknown structure. The DNA G+C content of strain S26(T) was 62.2 mol%. 16S rRNA gene sequence analysis showed that strain S26(T) is a member of the order Planctomycetales. Among taxonomically characterized representatives of this order, highest levels of 16S rRNA gene sequence similarity (95.1-95.2%) were observed with strains of the non-filamentous, peat-inhabiting planctomycete Singulisphaera acidiphila. Strain S26(T) could be differentiated from Singulisphaera acidiphila based on pigmentation, significant differences in substrate utilization patterns, greater tolerance of acidic conditions and the presence of C(16:1)ω9c. Based on the data presented, strain S26(T) is considered to represent a novel species of the genus Singulisphaera, for which the name Singulisphaera rosea sp. nov. is proposed; the type strain is S26(T) (=DSM 23044(T)=VKM B-2599(T)).

  1. Monitoring Heavy Metal Contents with Sphagnum Junghuhnianum Moss Bags in Relation to Traffic Volume in Wuxi, China

    Directory of Open Access Journals (Sweden)

    Rong Hu

    2018-02-01

    Full Text Available Despite its small size, a moss bag can reveal the different temporal and spatial deposition patterns of pollutants at a particular site; therefore, researchers can use moss bags to determine pollution sources and to put forward strategies for pollution control. Although the use of moss bags to monitor atmospheric pollution has been widely reported in Europe, there are few such empirical studies in China. Thus, in this study, bags containing the moss Sphagnum junghuhnianum were used to assess the concentrations of heavy metals (chromium (Cr, copper (Cu, lead (Pb, vanadium (V, and zinc (Zn at five sampling sites (four roads and a forest park during the summer and winter of 2012. According to the relative accumulation factor (RAF and contamination factor (CF results, pollution in winter was heavier than that in summer, and Cr was found to be the most contaminating, having the highest mean CF. There was a significant positive correlation (p < 0.05 between traffic volume and concentration for three heavy metals (Cr, Cu, and V in winter, whereas a significant positive correlation (p < 0.05 was observed between traffic volume and concentrations for four heavy metal elements (Cr, Pb, V, and Zn in summer, indicating a close relationship between heavy metal contents and traffic volume. Although there was substantial variation in the concentrations of the five heavy metals in the moss bags, significant correlations between heavy metals suggested that the contaminants originated from a common source, namely vehicle emissions. The results demonstrated that the four roads were subject to different degrees of pollution depending on the volume of traffic using each road. Therefore, the results of this study suggest that traffic volume is a major reason for heavy metal pollution.

  2. Nitrogen and sulphur deposition and the growth of Sphagnum fuscum in bogs of the Athabasca Oil Sands Region, Alberta

    Directory of Open Access Journals (Sweden)

    Melanie A. VILE

    2010-08-01

    Full Text Available One of the consequences of ongoing development of the oil sands reserve in the Athabasca Oil Sands Region (AOSR near Fort McMurray, Alberta, Canada (56° 39' N, 111° 13' W is an increase in emissions of nitrogen (N and sulphur (S, with an attendant increases in regional atmospheric N and S deposition. Regional land cover across northeastern Alberta is a mixture of Boreal Mixedwood, Boreal Highlands, and Subarctic areas. Peatlands occupy between 22 and 66% of these natural regions, and the land cover of bogs varies between 6.7% in the Mixedwood Region to 46% in the Subarctic Region. Ombrotrophic bog ecosystems may be especially sensitive to atmospheric deposition of N and S. Across 10 ombrotrophic bog sites in the AOSR over four years (2005– 2008, we found no evidence of elevated deposition of NH4 +-N, NO3 –-N, total inorganic nitrogen (TIN; NH4 +-N plus NO3 –-N, or SO4 2–-S, with values measured using ion exchange resin collectors averaging 0.61 ± 04, 0.20 ± 0.01, 0.81 ± 0.04, and 1.14 ± 0.06 kg ha–1 y–1, respectively. Vertical growth and net primary production of Sphagnum fuscum, an indicator of elevated deposition, did not differ consistently across sites, averaging 11.8 ± 0.2 mm y–1 and 234 ± 3.3 g m–2 y–1, respectively, over the four years. Neither vertical growth nor net primary production of S. fuscum was correlated with growing season atmospheric N or S deposition. Our data provide a valuable benchmark of background values for monitoring purposes in anticipation of increasing N and S deposition over a broader geographic region within the AOSR.

  3. Monitoring Heavy Metal Contents with Sphagnum Junghuhnianum Moss Bags in Relation to Traffic Volume in Wuxi, China.

    Science.gov (United States)

    Hu, Rong; Yan, Yun; Zhou, Xiaoli; Wang, Yanan; Fang, Yanming

    2018-02-22

    Despite its small size, a moss bag can reveal the different temporal and spatial deposition patterns of pollutants at a particular site; therefore, researchers can use moss bags to determine pollution sources and to put forward strategies for pollution control. Although the use of moss bags to monitor atmospheric pollution has been widely reported in Europe, there are few such empirical studies in China. Thus, in this study, bags containing the moss Sphagnum junghuhnianum were used to assess the concentrations of heavy metals (chromium (Cr), copper (Cu), lead (Pb), vanadium (V), and zinc (Zn)) at five sampling sites (four roads and a forest park) during the summer and winter of 2012. According to the relative accumulation factor (RAF) and contamination factor (CF) results, pollution in winter was heavier than that in summer, and Cr was found to be the most contaminating, having the highest mean CF. There was a significant positive correlation ( p heavy metals (Cr, Cu, and V) in winter, whereas a significant positive correlation ( p heavy metal elements (Cr, Pb, V, and Zn) in summer, indicating a close relationship between heavy metal contents and traffic volume. Although there was substantial variation in the concentrations of the five heavy metals in the moss bags, significant correlations between heavy metals suggested that the contaminants originated from a common source, namely vehicle emissions. The results demonstrated that the four roads were subject to different degrees of pollution depending on the volume of traffic using each road. Therefore, the results of this study suggest that traffic volume is a major reason for heavy metal pollution.

  4. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    NARCIS (Netherlands)

    Tsyganov, A.N.; Aerts, R.; Nijs, I.; Cornelissen, J.H.C.; Beyens, L.

    2012-01-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming,

  5. Response of sphagnum peatland testate amoebae to a 1-year transplantation experiment along an artificial hydrological gradient.

    Science.gov (United States)

    Marcisz, Katarzyna; Fournier, Bertrand; Gilbert, Daniel; Lamentowicz, Mariusz; Mitchell, Edward A D

    2014-05-01

    Peatland testate amoebae (TA) are well-established bioindicators for depth to water table (DWT), but effects of hydrological changes on TA communities have never been tested experimentally. We tested this in a field experiment by placing Sphagnum carpets (15 cm diameter) collected in hummock, lawn and pool microsites (origin) at three local conditions (dry, moist and wet) using trenches dug in a peatland. One series of samples was seeded with microorganism extract from all microsites. TA community were analysed at T0: 8-2008, T1: 5-2009 and T2: 8-2009. We analysed the data using conditional inference trees, principal response curves (PRC) and DWT inferred from TA communities using a transfer function used for paleoecological reconstruction. Density declined from T0 to T1 and then increased sharply by T2. Species richness, Simpson diversity and Simpson evenness were lower at T2 than at T0 and T1. Seeded communities had higher species richness in pool samples at T0. Pool samples tended to have higher density, lower species richness, Simpson diversity and Simpson Evenness than hummock and/or lawn samples until T1. In the PRC, the effect of origin was significant at T0 and T1, but the effect faded away by T2. Seeding effect was strongest at T1 and lowest vanished by T2. Local condition effect was strong but not in line with the wetness gradient at T1 but started to reflect it by T2. Likewise, TA-inferred DWT started to match the experimental conditions by T2, but more so in hummock and lawn samples than in pool samples. This study confirmed that TA responds to hydrological changes over a 1-year period. However, sensitivity of TA to hydrological fluctuations, and thus the accuracy of inferred DWT changes, was habitat specific, pool TA communities being least responsive to environmental changes. Lawns and hummocks may be thus better suited than pools for paleoecological reconstructions. This, however, contrasts with the higher prediction error and species' tolerance for

  6. Acidicapsa borealis gen. nov., sp. nov. and Acidicapsa ligni sp. nov., subdivision 1 Acidobacteria from Sphagnum peat and decaying wood.

    Science.gov (United States)

    Kulichevskaya, Irina S; Kostina, Lilia A; Valásková, Vendula; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; de Boer, Wietse; Dedysh, Svetlana N

    2012-07-01

    Two strains of subdivision 1 Acidobacteria, a pink-pigmented bacterium KA1(T) and a colourless isolate WH120(T), were obtained from acidic Sphagnum peat and wood under decay by the white-rot fungus Hyploma fasciculare, respectively. Cells of these isolates were Gram-negative-staining, non-motile, short rods, which were covered by large polysaccharide capsules and occurred singly, in pairs, or in short chains. Strains KA1(T) and WH120(T) were strictly aerobic mesophiles that grew between 10 and 33 °C, with an optimum at 22-28 °C. Both isolates developed under acidic conditions, but strain WH120(T) was more acidophilic (pH growth range 3.5-6.4; optimum, 4.0-4.5) than strain KA1(T) (pH growth range 3.5-7.3; optimum , 5.0-5.5). The preferred growth substrates were sugars. In addition, the wood-derived isolate WH120(T) grew on oxalate, lactate and xylan, while the peat-inhabiting acidobacterium strain KA1(T) utilized galacturonate, glucuronate and pectin. The major fatty acids were iso-C(15:0) and iso-C(17:1)ω8c; the cells also contained significant amounts of 13,16-dimethyl octacosanedioic acid. The quinone was MK-8. The DNA G+C contents of strains KA1(T) and WH120(T) were 54.1 and 51.7 mol%, respectively. Strains KA1(T) and WH120(T) displayed 97.8% 16S rRNA gene sequence similarity to each other. The closest recognized relatives were Acidobacterium capsulatum and Telmatobacter bradus (93.4-94.3% 16S rRNA gene sequence similarity). These species differed from strains KA1(T) and WH120(T) by their ability to grow under anoxic conditions, the absence of capsules, presence of cell motility and differing fatty acid composition. Based on these differences, the two new isolates are proposed as representing a novel genus, Acidicapsa gen. nov., and two novel species. Acidicapsa borealis gen. nov., sp. nov. is the type species for the new genus with strain KA1(T) (=DSM 23886(T)=LMG 25897(T)=VKM B-2678(T)) as the type strain. The name Acidicapsa ligni sp. nov. is proposed for

  7. Caracterización de la comunidad de macroinvertebrados de la Quebrada Paloblanco de la Cuenca del Río Otún (Risaralda, Colombia

    Directory of Open Access Journals (Sweden)

    Eleonora Bernal Pinilla

    2006-07-01

    Full Text Available Se realizó un estudio de las comunidades de macroinvertebrados presentes en la quebrada Paloblanco, ubicada en la cuenca del río Otún (Risaralda, Colombia. Los puntos de muestreo seleccionados corresponden a la cabecera y la zona cercana a la desembocadura en el río Otún, ambos con características geomorfológicas de corrientes de primer orden. En cada punto se colectaron los macroinvertebrados de las unidades funcionales hojarasca, epiliton, musgo y grava, junto con una muestra de deriva y fauna general (sin discriminar unidad funcional. Se encontraron 42 familias de Insecta, además de Acari, Annelida, Crustacea e Hirudinea. Igualmente se encontraron familias de presencia exclusiva en cada punto, mostrando diferencias en la composición de las comunidades. Los índices ecológicos empleados mostraron una mayor diversidad en punto bajo y diferencias entre algunas de las unidades funcionales, relacionados con el medio y los hábitos presentes. Para el análisis se tuvieron en cuenta los conceptos de continuo y zonación de los ríos. A pesar de tener condiciones de primer orden, existen variaciones a pequeña escala entre los puntos de muestreo, que están relacionadas con la intervención antrópica en la zona aledaña a punto bajo.

  8. [Optimization of a cake formulation with functional characteristics using resistant starch, Sphagnum magellanicum moss and deffated hazel nut flour (Gevuina avellana, Mol)].

    Science.gov (United States)

    Villarroel, Mario; Reyes, Carla; Hazbun, Julia; Karmelic, Julia

    2007-03-01

    Resistant starch (RS) Hi Maize 260, Sphagnum magellanicum Moss (SM) both natural resources rich in total dietary fiber, and defatted hazel nut flour (DHN) as protein resource were used in the development of a pastry product (queque) with functional characteristics. Taguchi methodology was utilized in the optimization process using the orthogonal array L934 with four control factors: RS, SM. DHN and Master Gluten 4000 (MG), 3 factor levels and 9 experimental trials. The best result of Sensory Quality (SQ) and signal to noise ratio (S/N) was obtained combining the minor levels of the independent variables. Main effect (average effects of factor) analysis and anova analysis showed that SM and DHN were the control factors with a significant influence (pcakes showed very good results when they were submitted to hedonic test with 100% of favorable consumer's opinions.

  9. Potencial del Agua del suelo

    Directory of Open Access Journals (Sweden)

    Bustamante Heliodoro

    1986-12-01

    Full Text Available La energía potencial del agua presenta diferencias de un punto del suelo a otro; esas diferencias son las que originan el movimiento del agua de acuerdo a la tendencia universal de la materia en el sentido de moverse de donde la energía potencial es mayor a donde dicha energía es menor. En el suelo el agua en consecuencia se mueve hacia donde su energía decrece hasta lograr su estado de equilibrio. Se desprende entonces que la cantidad de energía potencial absoluta contenida en el agua, no es importante por sí misma, sino por su relación con la energía en diferentes lugares dentro del suelo. El concepto Potencial de agua del suelo es un criterio para esta energía.

  10. del alcoholismo

    Directory of Open Access Journals (Sweden)

    Rodrigo Arias Duque

    2005-01-01

    Full Text Available Desde el punto de vista farmacológico, es importante comprender qué es el alcohol y cómo actúa en el organismo. No existe una causa simple, sino una interacción complicada de factores neuroquímicos, fisiológicos, psicológicos y sociales que originan y desarrollan esta grave enfermedad fármaco-dependiente. La acción psicofisiológica y farmacodinámica del alcohol es fundamentalmente depresiva, por la reducción de la transmisión sináptica en el sistema nervioso humano. Es un hecho conocido que el consumo excesivo de alcohol causa una disfunción aguda y crónica del cerebro, produciendo trastornos en el sistema nervioso central, presentando alteraciones en la memoria y en las funciones intelectuales como cálculo, comprensión y aprendizaje. A nivel hepático tiene lugar, en su mayoría, el metabolismo del alcohol, produciéndose un hígado graso alcohólico, aumentando el tamaño, terminando en necrosis e inflamación grave del hígado; esto se llama hepatitis alcohólica, y si se sigue consumiendo alcohol se desarrollará la cirrosis. El alcohol también ha estado relacionado con alteraciones del miocardio; se ha constatado en animales de experimentación sanos que tanto la velocidad de contracción del músculo cardiaco y su máxima tensión disminuyen en presencia del alcohol, como consecuencia, la fuerza de cada contracción y el aumento de presión en el ventrículo izquierdo son menores, perdiendo eficacia el corazón como bomba.

  11. Towards better understanding of the response of Sphagnum peatland to increased temperature and reduced precipitation in Central Europe

    Science.gov (United States)

    Juszczak, Radoslaw; Basińska, Anna; Chojnicki, Bogdan; Gąbka, Maciej; Hoffmann, Mathias; Józefczyk, Damian; Lamentowicz, Mariusz; Leśny, Jacek; Łuców, Dominika; Moni, Christophe; Reczuga, Monika; Samson, Mateusz; Silvennoinen, Hanna; Stróżecki, Marcin; Urbaniak, Marek; Zielińska, Małgorzata; Olejnik, Janusz

    2017-04-01

    With respect to climate change peatlands are highly vulnerable ecosystems. Especially a potential drying in future might result in a major carbon source and release to the atmosphere. We carried out a field climate manipulation experiment at Rzecin peatland in western Poland to assess how increased temperature and reduced precipitation may impact carbon balance, vegetation, microbes and water chemistry of the Sphagnum peatland. Here, we present results of measurements conducted in two contrasting years (417 mm and 678 mm of precipitation in very dry 2015 and wet 2016, respectively). The experimental design consists of four treatments, each one replicated three times (control, CO; simulated warming, W; prolonged drought, D and warming & drought, W+D). Increased temperatures (T) during the year were achieved by infrared heaters (400W × 4 per site, approx. 60 Wṡm-2 addition of LW radiation). Precipitation was reduced using an automatic curtain, covering the site during nighttime hours of the growth seasons. The manipulation experiment was successful during both years, increasing the air (30 cm height) and soil temperature (5 cm depth, sites W and D) by up to 0.2 oC and 1.0 oC, respectively. Precipitation was reduced to 37 % during both years. At W+D site the peat temperature was nearly two times higher than on W site indicating the impact of drought on T increase. To study the C exchange we developed an automatic mobile platform for measuring CO2/CH4/H2O fluxes (LGR) as well as 13CO2 and 13CH4 fluxes (PICARRO CRDS G2201-i). Measurements were performed, using dynamic ecosystem chambers (for NEE and Reco) and combined with simultaneous measurements of surface spectral properties. Flux calculation and gap filling was done according to Hoffmann et al. 2015. Methane emissions were significantly higher on manipulated plots than on CO (25 gCṡm-2yr-1) during both years, but only in the very dry 2015, CH4 fluxes were the highest on W+D site (33 gC gCṡm-2yr-1). Besides

  12. Culturas del Mundo

    DEFF Research Database (Denmark)

    Benwell, Ann Fenger; Costa, Alberto; Waehle, Espen

    2006-01-01

    ’Culturas del mundo. Colecciones del Museo Nacional de Dinamarca’ with Ann Fenger Benwell in Culturas del Mundo. Colecciones del Museo Nacional de Dinamarca, ed. Silvia Sauquet, Fundación "la Caixa", Barcelona 2006, pp. 31-39......’Culturas del mundo. Colecciones del Museo Nacional de Dinamarca’ with Ann Fenger Benwell in Culturas del Mundo. Colecciones del Museo Nacional de Dinamarca, ed. Silvia Sauquet, Fundación "la Caixa", Barcelona 2006, pp. 31-39...

  13. Caracterización florística e hidrológica de turberas de la Isla Grande de Chiloé, Chile Floristic and hydrological characterization of Chiloé Island peatlands, Chile

    Directory of Open Access Journals (Sweden)

    MARÍA F DÍAZ

    2008-12-01

    Full Text Available Las turberas son ecosistemas reconocidos mundialmente por actuar como grandes reservorios de agua dulce, afectando el clima y la hidrología local; por ser sumideros de carbono; por albergar especies únicas, contribuyendo así a la biodiversidad; y porque significan un recurso económico para la sociedad. La vegetación de las turberas es dominada por plantas que crecen a ras de suelo formando densas poblaciones, en especial musgos del género Sphagnum o plantas vasculares de la familia de las Ciperáceas o Juncáceas. Presentan altos niveles freáticos y una profunda capa de materia orgánica (turba bajo la capa viva de plantas. La tala y quema de bosques en sitios con drenaje pobre han generado un tipo de ecosistema similar a las turberas donde crece principalmente el musgo Sphagnum (turberas antropogénicas o "pomponales", pero donde la acumulación de turba aún es muy baja. Mientras las turberas naturales son utilizadas para la extracción de turba, en las turberas antropogénicas se cosecha el musgo vivo que se encuentra en la superficie. Las consecuencias ecológicas después de ambas actividades extractivas son distintas. El objetivo de este trabajo es hacer una comparación de la composición florística y de los niveles freáticos entre turberas naturales y antropogénicas. Fueron estudiadas turberas naturales y antropogénicas con y sin extracción de Sphagnum. Se registraron 74 taxa (ocho liqúenes, 19 briófitas y 47 de plantas vasculares. Las diferencias en composición florística nos permiten distinguir entre turberas naturales y antropogénicas. Los niveles freáticos también difieren entre sitios, siendo menos superficiales en turberas naturales y antropogénicas sin extracción, que en turberas antropogénicas con extracción de Sphagnum. Debido a la inexistencia de nieves eternas en la Isla de Chiloé, la alteración hidrológica de estos reservorios de agua dulce proveniente de las lluvias puede traer graves consecuencias

  14. Seasonal and inter-annual variation in the chlorophyll content of three co-existing Sphagnum species exceeds the effect of solar UV reduction in a subarctic peatland.

    Science.gov (United States)

    Hyyryläinen, Anna; Rautio, Pasi; Turunen, Minna; Huttunen, Satu

    2015-01-01

    We measured chlorophyll (chl) concentration and chl a/b ratio in Sphagnum balticum, S. jensenii, and S. lindbergii, sampled after 7 and 8 years of ultraviolet-B (UVB) and temperature manipulation in an open field experiment in Finnish Lapland (68°N). We used plastic filters with different transmittance of UVB radiation to manipulate the environmental conditions. The plants were exposed to (1) attenuated UVB and increased temperature, (2) ambient UVB and increased temperature and (3) ambient conditions. Chlorophyll was extracted from the capitula of the mosses and the content and a/b ratio were measured spectrophotometrically. Seasonal variation of chlorophyll concentration in the mosses was species specific. Temperature increase to 0.5-1 °C and/or attenuation of solar UVB radiation to ca. one fifth of the ambient (on average 12 vs. 59 uW/cm(2)) had little effect on the chlorophyll concentration or its seasonal variation. In the dominant S. lindbergii, UVB attenuation under increased temperature led to a transient decrease in chlorophyll concentration. Altogether, species-specific patterns of seasonal chlorophyll variation in the studied Sphagna were more pronounced than temperature and UVB treatment effects.

  15. PCA and multidimensional visualization techniques united to aid in the bioindication of elements from transplanted Sphagnum palustre moss exposed in the Gdańsk City area.

    Science.gov (United States)

    Astel, Aleksander; Astel, Karolina; Biziuk, Marek

    2008-01-01

    During the last decades, a technique for assessing atmospheric deposition of heavy elements was developed based on the principle that samples of moss are able to accumulate elements and airborne particles from rain, melting snow and dry deposition. Despite a broad interest in bioindication there are still ongoing works aimed at the preparation of a standard procedure allowing for a comparison of research carried out in various areas. This is why the comparison of living and dry moss of the same species and growth site seems to be interesting, logical and promising. A most reliable approach seems to be the application of bioindication connected with multivariate statistics and efficient visualization techniques in the interpretation of monitoring data. The aim of this study was: (i) to present cumulative properties of transplanted Sphagnum palustre moss with differentiation into dry and living biomaterial; (ii) to determine and geographically locate types of pollution sources responsible for a structure of the monitoring data set; (iii) to visualize geographical distribution of analytes in the Gdańsk metropolitan area and to identify the high-risk areas which can be targeted for environmental hazards and public health. A six month air pollution study based on Sphagnum palustre bioindication is presented and a simplified procedure of the experiment is given. The study area was located at the mouth of the Vistula River on the Baltic Sea, in Gdańsk City (Poland). Sphagnum palustre was selected for research because of its extraordinary morphological properties and its ease in being raised. The capability of dry and living moss to accumulate elements characteristic for anthropogenic and natural sources was shown by application of Principal Component Analysis. The high-risk areas and pollution profiles are detected and visualized using surface maps based on Kriging algorithm. The original selection of elements included all those that could be reliably determined by

  16. Combining short-term manipulative experiments with long-term palaeoecological investigations at high resolution to assess the response of Sphagnum peatlands to drought, fire and warming

    Directory of Open Access Journals (Sweden)

    M. Lamentowicz

    2016-09-01

    Full Text Available Northern hemisphere peatlands are substantial carbon stores. However, recent climate change and human impacts (e.g., drainage and atmospheric nutrient deposition may trigger the emission of their stored carbon to the atmosphere. Biodiversity losses are also an important consequence of those changes. Therefore, there is a need to recognise these processes in space and time. Global change experiments are often conducted to improve our understanding of the potential responses of various ecosystems to global warming and drought. Most of the experiments carried out in peatlands are focused on carbon balance and nitrogen deposition. Nevertheless, it is still unclear how fast peatlands respond to temperature changes and water-table lowering in the continental climate setting. This is important because continental regions account for a significant proportion of all northern hemisphere peatlands. A combination of short-term and long-term approaches in a single research project is especially helpful because it facilitates the correct interpretation of experimental data. Here we describe the CLIMPEAT project - a manipulative field experiment in a Sphagnum-dominated peatland supported by a high-resolution multi-proxy palaeoecological study. The design of the field experiment (e.g., treatments, methodology and biogeographical setting are presented. We suggest it is beneficial to support field experiments with an investigation of past environmental changes in the studied ecosystem, as human impacts during the past 300 years have already caused substantial changes in ecosystem functioning which may condition the response in experimental studies.

  17. Modelling and mapping trace element accumulation in Sphagnum peatlands at the European scale using a geomatic model of pollutant emissions dispersion.

    Science.gov (United States)

    Diaz-de-Quijano, Maria; Joly, Daniel; Gilbert, Daniel; Toussaint, Marie-Laure; Franchi, Marielle; Fallot, Jean-Michel; Bernard, Nadine

    2016-07-01

    Trace elements (TEs) transported by atmospheric fluxes can negatively impact isolated ecosystems. Modelling based on moss-borne TE accumulation makes tracking TE deposition in remote areas without monitoring stations possible. Using a single moss species from ombrotrophic hummock peatlands reinforces estimate quality. This study used a validated geomatic model of particulate matter dispersion to identify the origin of Cd, Zn, Pb and Cu accumulated in Sphagnum capillifolium and the distance transported from their emission sources. The residential and industrial sectors of particulate matter emissions showed the highest correlations with the TEs accumulated in S. capillifolium (0.28(Zn)-0.56(Cu)) and (0.27(Zn)-0.47(Cu), respectively). Distances of dispersion varied depending on the sector of emissions and the considered TE. The greatest transportation distances for mean emissions values were found in the industrial (10.6 km when correlating with all TEs) and roads sectors (13 km when correlating with Pb). The residential sector showed the shortest distances (3.6 km when correlating with Cu, Cd, and Zn). The model presented here is a new tool for evaluating the efficacy of air pollution abatement policies in non-monitored areas and provides high-resolution (200 × 200 m) maps of TE accumulation that make it possible to survey the potential impacts of TEs on isolated ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Kinetics and thermodynamics of adsorption of azinphosmethyl from aqueous solution onto pyrolyzed (at 600 deg. C) ocean peat moss (Sphagnum sp.)

    International Nuclear Information System (INIS)

    Aroguz, A.Z.

    2006-01-01

    The removal of azinphosmethyl from aqueous solution onto pyrolyzed ocean peat moss (Sphagnum sp.), as a residue, from the Rhode Island coast (USA), has been investigated at different temperatures and initial concentrations. The ocean peat moss had been pyrolyzed at 600 deg. C in nitrogen atmosphere before the adsorption process. The kinetic data obtained from batch studies have been analyzed using pseudo-first order kinetic model. The rate constants were evaluated at different temperatures. The thermodynamic parameters (ΔG o , ΔH o , ΔS o ) for the adsorption process were calculated and the results suggest that the nature of adsorption is endothermic and the process is spontaneous and favorable. The activation energy for adsorption process was estimated, about 18.3 kJ mol -1 . According to this value the adsorption of azinphosmethyl onto pyrolyzed ocean peat moss is in the range of physical adsorption. The experimental data have been modeled using Langmuir, Freundlich and Temkin isotherms. It was found that Langmuir and Freundlich isotherms give the best correlation with the experimental data

  19. The effects of quantitative fecundity in the haploid stage on reproductive success and diploid fitness in the aquatic peat moss Sphagnum macrophyllum.

    Science.gov (United States)

    Johnson, M G; Shaw, A J

    2016-06-01

    A major question in evolutionary biology is how mating patterns affect the fitness of offspring. However, in animals and seed plants it is virtually impossible to investigate the effects of specific gamete genotypes. In bryophytes, haploid gametophytes grow via clonal propagation and produce millions of genetically identical gametes throughout a population. The main goal of this research was to test whether gamete identity has an effect on the fitness of their diploid offspring in a population of the aquatic peat moss Sphagnum macrophyllum. We observed a heavily male-biased sex ratio in gametophyte plants (ramets) and in multilocus microsatellite genotypes (genets). There was a steeper relationship between mating success (number of different haploid mates) and fecundity (number of diploid offspring) for male genets compared with female genets. At the sporophyte level, we observed a weak effect of inbreeding on offspring fitness, but no effect of brood size (number of sporophytes per maternal ramet). Instead, the identities of the haploid male and haploid female parents were significant contributors to variance in fitness of sporophyte offspring in the population. Our results suggest that intrasexual gametophyte/gamete competition may play a role in determining mating success in this population.

  20. Sphagnum palustre clone vs native Pseudoscleropodium purum: A first trial in the field to validate the future of the moss bag technique.

    Science.gov (United States)

    Capozzi, F; Adamo, P; Di Palma, A; Aboal, J R; Bargagli, R; Fernandez, J A; Lopez Mahia, P; Reski, R; Tretiach, M; Spagnuolo, V; Giordano, S

    2017-06-01

    Although a large body of literature exists on the use of transplanted mosses for biomonitoring of air pollution, no article has addressed so far the use and the accumulation performance of a cloned moss for this purpose. In this work, a direct comparison of metal accumulation between bags filled with a Sphagnum palustre L. clone or with native Pseudoscleropodium purum Hedw., one of the most used moss species in biomonitoring surveys, was investigated. The test was performed in sites with different atmospheric contamination levels selected in urban, industrial, agricultural and background areas of Italy and Spain. Among the eighteen elements investigated, S. palustre was significantly enriched in 10 elements (Al, Ba, Cr, Cu, Fe, Hg, Pb, Sr, V and Zn), while P. purum was enriched only in 6 elements (Al, Ba, Cu, Hg, Pb and Sr), and had a consistently lower uptake capacity than S. palustre. The clone proved to be more sensitive in terms of metal uptake and showed a better performance as a bioaccumulator, providing a higher accumulation signal and allowing a finer distinction among the different land uses and levels of pollution. The excellent uptake performance of the S. palustre clone compared to the native P. purum and its low and stable baseline elemental content, evidenced in this work, are key features for the improvement of the moss bag approach and its large scale application. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Fire activity and hydrological dynamics in the past 5700 years reconstructed from Sphagnum peatlands along the oceanic-continental climatic gradient in northern Poland

    Science.gov (United States)

    Marcisz, Katarzyna; Gałka, Mariusz; Pietrala, Patryk; Miotk-Szpiganowicz, Grażyna; Obremska, Milena; Tobolski, Kazimierz; Lamentowicz, Mariusz

    2017-12-01

    Fire is a critical component of many ecosystems and, as predicted by various climate models, fire activity may increase significantly in the following years due to climate change. Therefore, knowledge about the past fire activity of various ecosystems is highly important for future nature conservation purposes. We present results of high-resolution investigation of fire activity and hydrological changes in northern Poland. We analyzed microscopic charcoal from three Sphagnum-dominated peatlands located on the south of Baltic, on the oceanic-continental (west-east) climatic gradient, and reconstructed the history of fire in the last 5700 years. We hypothesize that air circulation patterns are highly important for local fire activity, and that fire activity is more intensive in peatlands influenced by continental air masses. We have found out that forest fires have been occurring regularly since the past millennia and were linked to climatic conditions. We show that fire activity (related to climate and fuel availability) was significantly higher in sites dominated by continental climate (northeastern Poland) than in the site located under oceanic conditions (northwestern Poland)-microscopic charcoal influx was 13.3 times higher in the eastern study site of the gradient, compared to the western study site. Recorded fire activity patterns were different between the sites in a long timescale. Moreover, most of the recorded charcoal peaks occurred during high water tables. Rising human pressure has caused droughts and water table instability, and substantial increase in fire activity in the last 400 years.

  2. Rates and Controls of N2 Fixation in Sphagnum spp. along the Hydrological Gradient - Beaver Pond to Bog Transition at Mer Bleue, Ontario, Canada

    Science.gov (United States)

    Zivkovic, T.; Moore, T. R.

    2014-12-01

    Many northern bogs with low atmospheric N inputs acquire N only via N2-fixation. Little is known about rates and controls on N2-fixation in bogs. The aim of this study was to: 1) test the important ecological drivers for N2-fixation, 2) investigate seasonal and temporal patterns of N2 fixation, and 3) to estimate current N2-fixation rates at Mer Bleue bog. We used acetylene reduction assay (ARA) to measure N2-fixation from June-October 2013 and 2014 (currently ongoing field season) along a hydrological gradient (beaver pond, hollows and hummocks). The highest ARA rates in 2013 growing season occurred in the pond in floating Sphagnum cuspidatum mats (50.3 ± 12.9 μmol m-2 d-1 Mean ± Std Err) which were up to 2.5 times latger than the rates found in the hummock with the lowest water table depth throughout the season. Two rain events during the summer 2013 increased ARA rates in all plots by 1 to 4 times, suggesting that moisture availability may play a crucial role on N2 fixation potential in the field. We are currently investigating the role of moisture, temperature, PAR and nutrient content (N, phosphorous and metals) on ARA along the gradient. In addition, we are using 15N2 enrichment method to estimate N2 fixation rates and compare them to ARA method at Mer Bleue bog.

  3. Il dono del racconto

    DEFF Research Database (Denmark)

    Polito, Paola

    1998-01-01

    L'articolo indaga a vari livelli strutturali del romanzo "Il coraggio del pettirosso" (rete metaforica, dialogismo diegetico, dialogismo come fenomeno di voce, strategie discorsive messe in atto dalla voce narrante, stile colloquiale) la complessa realizzazione testuale del genere narrativo...

  4. Seasonal variations in CO2 and CH4 fluxes of four different plant compositions of a Sphagnum-dominated Alpine peat bog

    Science.gov (United States)

    Drollinger, Simon; Maier, Andreas; Karer, Jasmin; Glatzel, Stephan

    2017-04-01

    Peatlands are the only type of ecosystems which have the ability to accumulate significant amounts of carbon (C) under undisturbed conditions. The amount of C sequestered in peatlands depends on the balance between gross primary production, ecosystem respiration and decomposition of plant material. Sphagnum-dominated bogs possess the greatest peat accumulation potential of all peatlands, thus in turn, feature highest C release potentials. Many studies report about the C balances of undisturbed northern peat bogs, however, little is known about the effects of peatland degradation on the C balance between different plant compositions within peat bog ecosystems. Particularly in the Alpine region, where temperature increase during the last century has been almost twice as high as the global mean. The investigated peat bog is located in the inner Alpine Enns valley in the Eastern Alps, Austria (N 47˚ 34.873' E 14˚ 20.810'). It is a pine peat bog covered by Sphagnum mosses and a present extent of about 62 ha. Due to increasing differences in surface height of the peatland compared to the surrounding areas and related lowered water retention capacity attributed to the subsidence of the adjacent intensively managed meadows on deeply drained peat soils, the function of the peatland as a carbon sink is strongly endangered. Hence, the current mean water table depth of the central peat bog area is about -12 cm. To reveal differences in peatland-atmosphere C exchanges within the peatland ecosystem, we investigated CO2 and CH4 fluxes of four different vegetation compositions (PM1-PM4) at the treeless central peat bog area. PM1 is dominated by the graminoids Rhynchospora alba and Eriophorum vaginatum. PM2 is inhabited by small individuals (< 35 cm) of the conifer Pinus mugo, whereas PM3 is dominated by the ericaceous plant Calluna vulgaris. PM4 again is populated by Pinus mugo, but higher growing (35 - 60 cm) and with corresponding higher amount of biomass. Fluxes were measured

  5. Nebela jiuhuensis nov. sp. (Amoebozoa; Arcellinida; Hyalospheniidae): A New Member of the Nebela saccifera - equicalceus - ansata Group Described from Sphagnum Peatlands in South-Central China.

    Science.gov (United States)

    Qin, Yangmin; Man, Baiying; Kosakyan, Anush; Lara, Enrique; Gu, Yansheng; Wang, Hongmei; Mitchell, Edward A D

    2016-09-01

    Hyalospheniids are among the most common and conspicuous testate amoebae in high-latitude peatlands and forest humus. These testate amoebae were widely studied as bioindicators and are increasingly used as models in microbial biogeography. However, data on their diversity and ecology are still very unevenly distributed geographically: notably, data are lacking for low-latitude peatlands. We describe here a new species, Nebela jiuhuensis, from peatlands near the Middle Yangtze River reach of south-central China with characteristic morphology. The test (shell) has hollow horn-like lateral extensions also found in N. saccifera, N. equicalceus (=N. hippocrepis), and N. ansata, three large species restricted mostly to Sphagnum peatlands of Eastern North America. Mitochondrial cytochrome oxidase (COI) data confirm that N. jiuhuensis is closely related to the morphologically very similar North American species N. saccifera and more distantly to N. ansata within the N. penardiana group. These species are all found in wet mosses growing in poor fens. Earlier reports of morphologically similar specimens found in South Korea peatlands suggest that N. jiuhuensis may be distributed in comparable peatlands in Eastern Asia (China and Korea). The discovery of such a conspicuous new species in Chinese peatlands suggests that many new testate amoebae species are yet to be discovered, including potential regional endemics. Furthermore, human activities (e.g., drainage, agriculture, and pollution) have reduced the known habitat of N. jiuhuensis, which can thus be considered as locally endangered. We, therefore, suggest that this very conspicuous micro-organism with a probably limited geographical distribution and specific habitat requirement should be considered as a flagship species for microbial biogeography as well as local environmental conservation and management. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

  6. Local adaptations in bryophytes revisited: the genetic structure of the calcium-tolerant peatmoss Sphagnum warnstorfii along geographic and pH gradients

    Science.gov (United States)

    Mikulášková, Eva; Hájek, Michal; Veleba, Adam; Johnson, Matthew G; Hájek, Tomáš; Shaw, Jonathan A

    2015-01-01

    Bryophytes dominate some ecosystems despite their extraordinary sensitivity to habitat quality. Nevertheless, some species behave differently across various regions. The existence of local adaptations is questioned by a high dispersal ability, which is thought to redistribute genetic variability among populations. Although Sphagnum warnstorfii is an important ecosystem engineer in fen peatlands, the causes of its rather wide niche along the pH/calcium gradient are poorly understood. Here, we studied the genetic variability of its global populations, with a detailed focus on the wide pH/calcium gradient in Central Europe. Principal coordinates analysis of 12 polymorphic microsatellite loci revealed a significant gradient coinciding with water pH, but independent of geography; even samples from the same fens were clearly separated along this gradient. However, most of the genetic variations remained unexplained, possibly because of the introgression from phylogenetically allied species. This explanation is supported by the small heterogeneous cluster of samples that appeared when populations morphologically transitional to S. subnites, S. rubellum, or S. russowii were included into the analysis. Alternatively, this unexplained variation might be attributed to a legacy of glacial refugia with recently dissolved ecological and biogeographic consequences. Isolation by distance appeared at the smallest scale only (up to 43 km). Negative spatial correlations occurred more frequently, mainly at long distances (up to 950 km), implying a genetic similarity among samples which are very distant geographically. Our results confirm the high dispersal ability of peatmosses, but simultaneously suggested that their ability to cope with a high pH/calcium level is at least partially determined genetically, perhaps via specific physiological mechanisms or a hummock-forming ability. PMID:25628880

  7. A comparison of lead pollution record in Sphagnum peat with known historical Pb emission rates in the British isles and the Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Novak, M.; Erel, Y.; Zemanova, L.; Bottrell, S.H.; Adamova, M. [Czech Geological Survey, Prague (Czech Republic)

    2008-12-15

    Vertical Pb concentration gradients and isotope ratios (Pb-206/Pb-207, Pb-208/Pb-207) are reported for five Pb-210-dated Sphagnum peat profiles. The studied peat bogs are in the British Isles (Thorne Moors, England; Mull, Scotland; and Connemara, Eire) and central Europe (Ocean, northern Czech Republic: Rybarenska slat, southern Czech Republic). Both the U.K. and the Czech Republic experienced maximum Pb emissions from Ag-Pb smelting around 1880. Pb emissions from coal burning peaked in 1955 in the U.K, and in the 1980s in the Czech Republic. In both countries, use of alkyl-lead additives to gasoline resulted in large Pb emissions between 1950 and 2000. We hypothesized that peaks in Pb emissions from smelting, coal burning and gasoline burning, respectively, should be mirrored in the peat profiles. However, a more complicated pattern emerged. Maximum annual Pb accumulation rates occurred in 1870 at Ocean, 1940 at Thorne Moors, 1988 at Rybarenska slat, and 1990 at Mull and Connemara. Atmospheric Pb inputs decreased in the order Thorne Moors {ge} Ocean > Rybarenska slat > Mull > Connemara. The Ocean bog was unique in the central European region in that its maximum Pb pollution dated back to the 19th century and coincided with maximum Pb smelting at Freiberg and Pribram. In contrast, numerous previously studied sites showed no Pb accumulation maximum in the 19th century, but increasing pollution until the 1980s. It remains unclear why Ocean did not record the regional peak in Pb emissions caused by high coal and gasoline burning around 1980, while an array of nearby bogs studied previously did record the 1980 coal/gasoline peak, but no 1880 smelting peak. Mean Pb-206/Pb-207 ratios of potential pollution sources were 1.07 and 1.11 for gasoline, 1.17 and 1.17 for local ores, and 1.18 and 1.19 for coal in the U.K. and the Czech Republic, respectively.

  8. Informing innovative peatland conservation in light of palaeoecological evidence for the demise of Sphagnum imbricatum: the case of Oxenhope Moor, Yorkshire, UK

    Directory of Open Access Journals (Sweden)

    J. McCarroll

    2016-04-01

    Full Text Available Actively growing mires have high conservation value and the potential to sequester carbon. However, drainage, burning, overgrazing and atmospheric pollution have led to depauperation of native flora and loss of peat at many peatland sites. In order to counteract such degradation, palaeoecological techniques can be applied and the data then used to inform nature conservation practice. The present study exemplifies this approach and was conducted on degraded blanket mire in Yorkshire, UK, in collaboration with a field-based moorland restoration agency. High-resolution, multiproxy palaeoecological analyses on a peat core from Oxenhope Moor were used to reconstruct Holocene vegetation changes spanning approximately the last 7000 years. Humification, pollen, plant macrofossil and charcoal analyses show distinct changes in species composition and indicate their potential causes. Human-induced changes identified at 2100 cal. BP are most likely to reflect deliberate clearance by fire. Sphagnum imbricatum disappears and is subsequently replaced by S. papillosum at ca. 1000 cal. BP, possibly due to drier conditions and competition between the two species. Increased human activity is identified since the Industrial Revolution where monocots and Eriophorum vaginatum increase, interpreted as a result of managed burning. It is intended that the long-term ecological history of the site, derived using palaeoecological techniques, will be used to inform conservation practice and can help set feasible targets for restoration and conservation. Specifically, encouraging a species mix that has pre-19th century longevity is suggested, including the specific recommendation that translocation of S. imbricatum be explored experimentally at this site, with a view to ascertaining likely success elsewhere.

  9. del cambio

    Directory of Open Access Journals (Sweden)

    Alejandro Canales

    2006-01-01

    Full Text Available El artículo analiza las propuestas y los compromisos en materia de cobertura y de financiamiento en el periodo 2000-2006. En particular, revisa las modificaciones y los ajustes de los tres principales documentos en los que se expresaron las iniciativas: el de la Asociación Nacional de Universidades e Instituciones de Educación Superior, el del equipo de la transición y el programa sectorial. Los resultados muestran que las cifras de atención a la demanda educativa e inversión quedaron lejos de las metas autoimpuestas por el gobierno federal y que será necesario realizar mayores esfuerzos para atender tales desafíos.

  10. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    Science.gov (United States)

    Tsyganov, Andrey N; Aerts, Rien; Nijs, Ivan; Cornelissen, Johannes H C; Beyens, Louis

    2012-05-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Ecohydrological features of some contrasting mires in Tierra del Fuego, Argentina

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    A. Grootjans

    2010-01-01

    Full Text Available In November 2005, Tierra del Fuego (Argentina hosted the biennial conference and field excursion of the International Mire Conservation Group (IMCG. The group considered the vegetation, hydrology, peat stratigraphy and possible management options for about 20 mires which were visited during a seven-day excursion. We report here some field observations and measurements of electrical conductivity (EC25 in five mires which have been selected to encompass the most important ecohydrological features of the mires of Tierra del Fuego. Existing and new data on landscape topography and vegetation were combined in three-dimensional drawings. These drawings are actually conceptual models which could underpin further ecohydrological research, and proved to be very useful as a basis for discussions amongst conference participants about possible ecohydrological relationships. The mires that were studied developed under a wide range of climatic conditions and included fens and bogs. The bogs typically developed from lakes or fens and most are now dominated by Sphagnum magellanicum. This species forms large hummocks, and can invade weakly-buffered fens. Most of the mires were well preserved, but effects of human impact - such as road building and peat extraction - were also noticeable.

  12. La superaci??n del modelo del ??ngel del hogar:

    OpenAIRE

    Hurtado Mu??oz, M??nica

    2012-01-01

    La Tesis Doctoral titulada "La superaci??n del modelo del "??ngel del hogar". Recuperaci??n de la escritora Leonor Canalejas y Fustegueras (1869-1945)" aborda, en primer lugar, un an??lisis sociol??gico de las circunstancias que rodearon a la mujer espa??ola en el cambio de siglo en el ??mbito social y educativo, en un intento de esclarecer las caracter??sticas propias del contexto en el que la mujer accede a la intelectualidad en general y a la literatura en particular. Esta parte concluye q...

  13. Methylocystis bryophila sp. nov., a facultatively methanotrophic bacterium from acidic Sphagnum peat, and emended description of the genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993.

    Science.gov (United States)

    Belova, Svetlana E; Kulichevskaya, Irina S; Bodelier, Paul L E; Dedysh, Svetlana N

    2013-03-01

    A novel species is proposed for two facultatively methanotrophic representatives of the genus Methylocystis, strains H2s(T) and S284, which were isolated from an acidic (pH 4.3) Sphagnum peat-bog lake (Teufelssee, Germany) and an acidic (pH 3.8) peat bog (European North Russia), respectively. Cells of strains H2s(T) and S284 are aerobic, Gram-negative, non-motile, curved coccoids or short rods that contain an intracytoplasmic membrane system typical of type-II methanotrophs. They possess both a soluble and a particulate methane monooxygenase (MMO); the latter is represented by two isozymes, pMMO1 and pMMO2. The preferred growth substrates are methane and methanol. In the absence of C1 substrates, however, these methanotrophs are capable of slow growth on acetate. Atmospheric nitrogen is fixed by means of an aerotolerant nitrogenase. Strains H2s(T) and S284 grow between pH 4.2 and 7.6 (optimum pH 6.0-6.5) and at 8-37 °C (optimum 25-30 °C). The major fatty acids are C18 : 1ω8c, C18 : 1ω7c and C16 : 1ω7c; the major quinone is Q-8. The DNA G+C content is 62.0-62.3 mol%. Strains H2s(T) and S284 share identical 16S rRNA gene sequences, which displayed 96.6-97.3 % similarity to sequences of other taxonomically characterized members of the genus Methylocystis. Therefore, strains H2s(T) and S284 are classified as members of a novel species, for which the name Methylocystis bryophila sp. nov. is proposed; strain H2s(T) ( = DSM 21852(T)  = VKM B-2545(T)) is the type strain.

  14. Fimbriiglobus ruber gen. nov., sp. nov., a Gemmata-like planctomycete from Sphagnum peat bog and the proposal of Gemmataceae fam. nov.

    Science.gov (United States)

    Kulichevskaya, Irina S; Ivanova, Anastasia A; Baulina, Olga I; Rijpstra, W Irene C; Sinninghe Damsté, Jaap S; Dedysh, Svetlana N

    2017-02-01

    An aerobic, budding, dark pink to red-pigmented bacterium was isolated from an acidic boreal Sphagnum peat bog and designated strain SP5T. Cells of this strain were non-motile spheres that were uniformly covered with crateriform pits and fimbria, and tended to form aggregates during growth in liquid media. Strain SP5T was capable of growth between pH 4.0 and pH 6.8 (optimum at pH 5.5-6.0) and at temperatures between 10 and 30 °C (optimum at 20-25 °C). The preferred growth substrates were sugars and some heteropolysaccharides. The major fatty acids were C20 : 1ω9c, C16 : 1ω9c and C16 : 0, and the major polar lipid was trimethylornithine. Cells contained also significant amounts of bound (ω-1)OH-C30 : 1 fatty acid. The quinone was menaquinone-6, and the G+C content of the DNA was 60.7 mol%. Strain SP5T was a member of the order Planctomycetales and belonged to the phylogenetic lineage defined by the genus Gemmata. It displayed 88 and 89 % 16S rRNA gene sequence similarity to Gemmata obscuriglobusUQM 2246T and 'Gemmata massiliana' IIL30, 89 % to Zavarzinella formosa A10T and 86 % to Telmatocola sphagniphila SP2T. However, strain SP5T differed from members of these genera by cell morphology, substrate utilization pattern and fatty acid composition. Based on these data, the novel isolate should be considered as representing a novel species of a new genus of planctomycetes, for which the name Fimbriiglobus ruber gen. nov., sp. nov, is proposed. The type strain is SP5T (=LMG 29572T=VKM B-3045T). We also suggest the establishment of a novel family, Gemmataceaefam. nov., which includes the phylogenetically related genera Gemmata, Zavarzinella, Telmatocola and Fimbriiglobus.

  15. How do climate and human impact affect Sphagnum peatlands under oceanic-continental climatic conditions? 2000 years of fire and hydrological history of a bog in Northern Poland

    Science.gov (United States)

    Marcisz, Katarzyna; Tinner, Willy; Colombaroli, Daniele; Kołaczek, Piotr; Słowiński, Michał; Fiałkiewicz-Kozieł, Barbara; Lamentowicz, Mariusz

    2014-05-01

    Climate change affects many natural processes and the same applies to human impact For instance climate change and anthropogenic activities may cause increased fire activity or change peatland dynamics. Currently it is still unknown how Sphagnum peatlands in the oceanic-continental transition zone of Poland may respond to combined effects of heat waves, drought and fire. The aim of the study was to reconstruct the last 2000 years palaeohydrology and fire history at Linje bog in Northern Poland. The main task was to determine the drivers of fire episodes, particularly to identify climatic and anthropogenic forcing. A two-meter peat core was extracted and subsampled with a high resolution. Micro- and macroscopic charcoal analyses were applied to determine past fire activity and the results compared with palaeohydrological reconstructions based on testate amoeba analysis. Palynological human indicators were used to reconstruct human activity. A depth-age model including 20 14C dates was constructed to calculate peat accumulation rates and charcoal influx. We hypothesised that: 1) fire frequency in Northern Poland was determined by climatic conditions (combination of low precipitation and heat waves), as reflected in peatland water table, and that 2) past fire episodes in the last millennium were intensified by human activity. Furthermore climate may have influenced human activity over harvest success and the carrying capacity. Our study shows that fire was important for the studied ecosystem, however, its frequency has increased in the last millennium in concomitance with land use activities. Landscape humanization and vegetation opening were followed by a peatland drying during the Little Ice Age (from ca. AD 1380). Similarly to other palaeoecological studies from Poland, Linje peatland possessed an unstable hydrology during the Little Ice Age. Increased fire episodes appeared shortly before the Little Ice Age and most severe fires were present in the time when

  16. A comparison of lead pollution record in Sphagnum peat with known historical Pb emission rates in the British Isles and the Czech Republic

    Science.gov (United States)

    Novak, Martin; Erel, Yigal; Zemanova, Leona; Bottrell, Simon H.; Adamova, Marie

    Vertical Pb concentration gradients and isotope ratios ( 206Pb/ 207Pb, 208Pb/ 207Pb) are reported for five 210Pb-dated Sphagnum peat profiles. The studied peat bogs are in the British Isles (Thorne Moors, England; Mull, Scotland; and Connemara, Eire) and central Europe (Ocean, northern Czech Republic; Rybarenska slat, southern Czech Republic). Both the U.K. and the Czech Republic experienced maximum Pb emissions from Ag-Pb smelting around 1880. Pb emissions from coal burning peaked in 1955 in the U.K. and in the 1980s in the Czech Republic. In both countries, use of alkyl-lead additives to gasoline resulted in large Pb emissions between 1950 and 2000. We hypothesized that peaks in Pb emissions from smelting, coal burning and gasoline burning, respectively, should be mirrored in the peat profiles. However, a more complicated pattern emerged. Maximum annual Pb accumulation rates occurred in 1870 at Ocean, 1940 at Thorne Moors, 1988 at Rybarenska slat, and 1990 at Mull and Connemara. Atmospheric Pb inputs decreased in the order Thorne Moors ≥ Ocean > Rybarenska slat > Mull > Connemara. The Ocean bog was unique in the central European region in that its maximum Pb pollution dated back to the 19th century and coincided with maximum Pb smelting at Freiberg and Pribram. In contrast, numerous previously studied sites showed no Pb accumulation maximum in the 19th century, but increasing pollution until the 1980s. It remains unclear why Ocean did not record the regional peak in Pb emissions caused by high coal and gasoline burning around 1980, while an array of nearby bogs studied previously did record the 1980 coal/gasoline peak, but no 1880 smelting peak. Mean 206Pb/ 207Pb ratios of potential pollution sources were 1.07 and 1.11 for gasoline, 1.17 and 1.17 for local ores, and 1.18 and 1.19 for coal in the U.K. and the Czech Republic, respectively. The calculated percentages of gasoline-derived Pb in peat (≤55% for the British Isles and ≤63% for the Czech Republic

  17. Late-Holocene hydroclimate and atmospheric circulation variability in southern Patagonia: insights from triple stable isotopes (δ18O, δ13C, δD) of peat bog Sphagnum moss

    Science.gov (United States)

    Xia, Z.; Yu, Z.; Zheng, Y.; Loisel, J.; Huang, Y.

    2017-12-01

    The Southern Hemisphere Westerly Winds (SHWWs) exert important influences on regional and global climates, but their long-term behaviors and dynamics are still poorly understood but critical for projecting future changes. Here we present a 5,500-year record from a Sphagnum-dominated peat bog located on the lee side of the Andes at 54.2 °S in southern Patagonia—based on plant macrofossils, Sphagnum cellulose δ18O and δ13C, and lipid δD data—to document and understand the variability in hydroclimate and atmospheric circulation. There is a striking negative correlation between cellulose δ18O and the Southern Annular Mode (SAM) index over the last millennium; particularly the 2.5‰ negative shift of δ18O is concurrent with the observed positive trend in the SAM over the recent decades. The interval of Medieval Climate Anomaly (MCA, 850-600 yr BP) is characterized by a 2.5‰ negative shift of δ18O and low δ13C values, while the Little Ice Age (LIA, 500-300 yr BP) is characterized by a 2.5‰ positive shift of δ18O and high δ13C values. Furthermore, we find the largest negative shift of δ18O ( 3‰) at 2,300 yr BP, suggesting a significantly positive shift in the SAM. We interpret high Sphagnum abundance and high cellulose δ13C values to reflect great moss moisture conditions, while cellulose δ18O variations primarily reflect moisture sources and atmospheric circulation. During the positive phase of SAM (e.g., the MCA and recent decades), strengthened SHWWs enhance the rain-shadow effect, resulting in dry climate and 18O-depleted precipitation (low δ18O values) in the study region. During the negative phase of SAM (e.g., the LIA), weakened SHWWs reduce rain-shadow effect, resulting in wet climate and high δ18O values caused by increases in moisture contributions from the southerly and easterly flows that do not experience strong Rayleigh distillation process during air mass transports. Furthermore, coupling cellulose δ18O and lipid δD enables

  18. Acerca del moho

    Science.gov (United States)

    El moho forma parte del medio ambiente natural. Afuera del hogar, el moho juega un papel en la naturaleza al desintegrar materias organicas tales como las hojas que se han caido o los arboles muertos. El moho puede crecer adentro del hogar cuando las espor

  19. Del bit al qubit

    OpenAIRE

    Torras Font, Josep

    2011-01-01

    Aquest document pretén donar una visió del desenvolupament dels computadors electrònics i dels components que els han fet possibles. Dintre de les opcions de futur en computació, també intenta donar una visió de les bases en que es fonamenta la computació quàntica.

  20. Detection and enumeration of methanotrophs in acidic Sphagnum peat by 16S rRNA fluorescence in situ hybridization, including the use of newly developed oligonucleotide probes for Methylocella palustris.

    Science.gov (United States)

    Dedysh, S N; Derakshani, M; Liesack, W

    2001-10-01

    Two 16S rRNA-targeted oligonucleotide probes, Mcell-1026 and Mcell-181, were developed for specific detection of the acidophilic methanotroph Methylocella palustris using fluorescence in situ hybridization (FISH). The fluorescence signal of probe Mcell-181 was enhanced by its combined application with the oligonucleotide helper probe H158. Mcell-1026 and Mcell-181, as well as 16S rRNA oligonucleotide probes with reported group specificity for either type I methanotrophs (probes M-84 and M-705) or the Methylosinus/Methylocystis group of type II methanotrophs (probes MA-221 and M-450), were used in FISH to determine the abundance of distinct methanotroph groups in a Sphagnum peat sample of pH 4.2. M. palustris was enumerated at greater than 10(6) cells per g of peat (wet weight), while the detectable population size of type I methanotrophs was three orders of magnitude below the population level of M. palustris. The cell counts with probe MA-221 suggested that only 10(4) type II methanotrophs per g of peat (wet weight) were present, while the use of probe M-450 revealed more than 10(6) type II methanotroph cells per g of the same samples. This discrepancy was due to the fact that probe M-450 targets almost all currently known strains of Methylosinus and Methylocystis, whereas probe MA-221, originally described as group specific, does not detect a large proportion of Methylocystis strains. The total number of methanotrophic bacteria detected by FISH was 3.0 (+/-0.2) x 10(6) cells per g (wet weight) of peat. This was about 0.8% of the total bacterial cell number. Thus, our study clearly suggests that M. palustris and a defined population of Methylocystis spp. were the predominant methanotrophs detectable by FISH in an acidic Sphagnum peat bog.

  1. Dust is the dominant source of "heavy metals" to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta.

    Science.gov (United States)

    Shotyk, William; Bicalho, Beatriz; Cuss, Chad W; Duke, M John M; Noernberg, Tommy; Pelletier, Rick; Steinnes, Eiliv; Zaccone, Claudio

    2016-01-01

    Sphagnum fuscum was collected from twenty-five ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands (ABS) in northern Alberta (AB) in order to assess the extent of atmospheric contamination by trace elements. As a control, this moss species was also collected at a bog near Utikuma (UTK) in an undeveloped part of AB and 264km SW of the ABS region. For comparison, this moss was also collected in central AB, in the vicinity of the City of Edmonton which is approximately 500km to the south of the ABS region, from the Wagner Wetland which is 22km W of the City, from Seba Beach (ca. 90km W) and from Elk Island National Park (ca. 45km E). All of the moss samples were digested and trace elements concentrations determined using ICP-SMS at a commercial laboratory, with selected samples also analyzed using instrumental neutron activation analysis at the University of Alberta. The mosses from the ABS region yielded lower concentrations of Ag, As, Bi, Cd, Cu, Pb, Sb, Tl, and Zn compared to the moss from the Edmonton area. Concentrations of Ni and Mo in the mosses were comparable in these two regions, but V was more abundant in the ABS samples. Compared with the surface vegetation of eight peat cores collected in recent years from British Columbia, Ontario, Quebec and New Brunswick, the mean concentrations of Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl and Zn in the mosses from the ABS region are generally much lower. In fact, the concentrations of these trace elements in the samples from the ABS region are comparable to the corresponding values in forest moss from remote regions of central and northern Norway. Lithophile element concentrations (Ba, Be, Ga, Ge, Li, Sc, Th, Ti, Zr) explain most of the variation in trace metal concentrations in the moss samples. The mean concentrations of Th and Zr are greatest in the moss samples from the ABS region, reflecting dust inputs to the bogs from open pit mines, aggregate

  2. Substratos para o enraizamento de microestacas de mirtileiro cultivar georgiagem

    Directory of Open Access Journals (Sweden)

    Nara Cristina Ristow

    2012-03-01

    Full Text Available O objetivo do trabalho foi verificar a viabilidade e definir um substrato adequado para o enraizamento de microestaquia e o crescimento de mudas de mirtileiro cultivar Georgiagem. Foram avaliados diferentes substratos para a técnica de microestaquia mantida em condições de microambiente úmido, com temperatura e luz controladas. As microestacas foram acondicionadas em caixas de politereftalato de etileno, durante 48 dias. Os substratos turfa de musgo Sphagnum sp. e as misturas turfa + perlita, turfa + perlita + fibra de coco, turfa + perlita + serragem permitiram a obtenção de maior percentual de enraizamento.

  3. Algunas aclaraciones acerca del conocimiento del singular.

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    Carlos Llano Cifuentes

    2013-11-01

    Full Text Available Llano tries to explain the main purpose of El Conocimiento del Singular, showing how the individuals about which the book is concerned are basically human individuals: people as decision makers.

  4. Psicodrama del duelo.

    OpenAIRE

    José Antonio Espina Barrio; Marisol Filgueira Bouza

    1997-01-01

    La pérdida de rituales agrava y alarga la reacción del duelo. Se define el Psicodrama Antropológico y su intervención en el proceso del duelo. El Psicodrama Focal del Duelo es una psicoterapia breve centrada en el proceso de Duelo. Se comentan varios casos y resultados. Se concluye con un programa sencillo para el duelo en Atención Primaria.

  5. Fractura triple del complejo suspensorio del hombro

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    Eraclio Delgado Rifá

    2015-06-01

    Full Text Available El complejo suspensorio del hombro es una estructura sumamente importante, compuesta por un anillo de huesos y tejidos blandos. Las lesiones aisladas de este complejo anatómico son frecuentes y no afectan su estabilidad. La interrupción doble conduce a la inestabilidad de esta estructura y usualmente requiere tratamiento quirúrgico. La triple interrupción, por su parte, es sumamente rara y es encontrada en casos de trauma de alta energía a menudo en asociación con otras lesiones. Se presenta una triple lesión del complejo suspensorio del hombro en un paciente de 46 años de edad, con una fractura de la glenoides, del acromion tipo III de Kuhn y de la coracoides tipo II de Ogawa. En este caso, la fractura del acromion fue tratada con fijación percutánea con alambres de Kirschner, por tener asociado lesiones de partes blandas que contraindicaron la reducción abierta. La fractura de la glenoides y de la apófisis coracoides fueron tratadas conservadoramente. Después de 6 meses de evolución, el paciente tuvo un resultado funcional aceptable, con una abducción de 90 grados, los 30 grados de rotación externa y 70 de rotación interna, además asintomático y consolidación de todas las fracturas. A pesar de ser catalogada de una lesión grave del cinturón escapular y estar asociada a otras lesiones se obtuvo un resultado satisfactorio al final del tratamiento.

  6. Vigencia del Darwinismo

    OpenAIRE

    Lessa, Enrique P

    2009-01-01

    En este ensayo se presenta una revisión histórica del signifcado y legado del darwinismo, con énfasis en el último siglo. La principal conclusión es que la visión darwiniana de la evolución, con las modifcaciones requeridas para dar cuenta de los grandes desarrollos de la disciplina, se ha impuesto y mantiene vigencia en nuestros días. En particular, el papel del azar, la evolución como proceso de “descendencia con modifcación” a lo largo de diversas ramas del árbol de la vida, el pensamiento...

  7. La luz del origen del universo

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    Casas, Alberto

    2015-10-01

    Full Text Available Penzias and Wilson discovered the cosmic microwave background, a luminous echo of the Big Bang, in 1965. The amount of information encoded in this relic of the early universe is truly extraordinary. At present, the most precise data about the origin and structure of the universe comes from the study of this primordial light, the full potential of which has yet to be explored.En 1965 se descubrió el fondo de radiación de microondas, un eco luminoso de la Gran Explosión (Big Bang. La cantidad de información contenida en esta reliquia del universo primitivo es verdaderamente extraordinaria. En la actualidad los datos más precisos sobre el origen y estructura del universo provienen del estudio de esta luz primigenia, que aún no ha sido explorada en todo su potencial.

  8. Archivo del Duelo

    OpenAIRE

    Ferrera, Tamara

    2010-01-01

    Photos taken from the Archive of Mourning following the March 11 terrorist attacks El Archivo del Duelo. Creación de un archivo etnográfico de los Atentados del 11 de marzo en Madrid. Ministerio de Educación y Ciencia HUM2005-03490.

  9. Displasias del seno

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    Ernesto Andrade Valderrama

    1971-04-01

    Full Text Available En general, las Displasias no se presentan antes de la iniciación del estímulo Gonadal y tienden a desaparecer con el climaterio. Se definen entonces como las afecciones benignas del Seno, de origen endocrino.

  10. Estudios ecológicos en la Cordillera Oriental IV: Aspectos sinecológicos de la brioflora de los depósitos turbosos paramunos de los alrededores de Bogotá Estudios ecológicos en la Cordillera Oriental IV: Aspectos sinecológicos de la brioflora de los depósitos turbosos paramunos de los alrededores de Bogotá

    Directory of Open Access Journals (Sweden)

    Sánchez M. Roberto

    1989-09-01

    Full Text Available Mediante los lineamientos metodológicos de la escuela Zurich-Montpellier (Braun-Blanquet, 1979 se realizaron 102 levantamientos de la vegetación que se establece en los pantanos, turberas o depósitos turbosos de los páramos de los alrededores de Bogotá. En la caracterización de esta vegetación, los musgos y las hepáticas desempeñan un papel importante; varias especies de Sphagnum son dominantes en diferentes fases del proceso de sucesión sobre esos ambientes originados de cubetas y lagunas glaciares. EI sustrato es muy variable en su constitución y en las características físico-químicas; en general, prevalece un contenido alto de materia orgánica, aceptable cantidad de nitrógeno y valores reducidos de elementos como magnesio, calcio y potasio. En esta contribución se presenta una reseña a nivel regional de las características primordiales de los sitios investigados en cuanto al papel desempeñado por las especies de briófitas en la composición florística, y a las condiciones físico-químicas del sustrato. The vegetation established on" peat deposits "or marshes in the paramos around Bogota is treated following the Zurich-Montpellier system. 102 releves of vegetation were realized. Mosses and liverVllorths play an important role in the structure and floristic composition of this vegetation.  Several Sphagnum species are dominant in some steps of the sucession process from open water and small lake to marsh. The constitution of the substrate and its physical and chemical characteristics vary in the places investigated, but in general terms there is a high content of organic matter, fair content of nitrogen and low content of magnesium, calcium and potassium.  

  11. La crisi del diritto del lavoro

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    Alessandro Garilli

    2012-01-01

    Full Text Available Riassunto - L’Autore ripercorre in chiave critica l’evoluzione delle politiche legislative in materia di lavoro, alla luce dell’attuale fase di crisi economico finanziaria. Nell’esaminare i principali interventi normativi attuati da inizio secolo, l’Autore mette in evidenza le scelte di metodo e gli elementi di continuità che accomunano i vari provvedimenti, individuandoli nell’affannosa ricerca del punto di equilibrio tra flessibilità e garantismo. La riflessione si chiude con alcuni interrogativi sulle ultime linee di riforma del mercato del lavoro e con l’auspicio che, anche al cospetto delle imprescindibili ragioni dell’economia, il diritto del lavoro possa continuare a svolgere il proprio tradizionale ruolo di disciplina di tutela della persona.   Abstract - The author analyzes, with a critically oriented approach, the development of the employment law, in the light of the current economic and financial crisis. In examining the main regulatory measures implemented since the beginning of the century, the author highlights the methodological choices and the elements of continuity that unite the various measures, focusing them in a hard research of a point of balance between flexibility and security. The discussion concludes with some questions about the last lines of the reform of the labor market and with the hope that, even in the face of compelling reasons of economy, labor law can continue to play its traditional role of governing the protection of person.

  12. OBJETIVO DEL DESARROLLO DEL MILENIO 7

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    Margarita M. Pérez O.

    2013-10-01

    Full Text Available Los Objetivos de Desarrollo del Milenio, también conocidos como los Objetivos del Milenio, constituyeron las metas finales que aprobaron los dirigentes mundiales, 189 jefes de estado y de gobierno en la Cumbre del Milenio de las Naciones Unidas celebrada en Nueva York en el año 2000, en la cual los Estados miembros de la organización reafirmaron su compromiso de luchar por un mundo en el que el desarrollo sostenible y la eliminación de la pobreza tuvieran máxima prioridad1 . En la cumbre se definió la Declaración del Milenio, la cual detalla los objetivos, principios, valores, metas y acciones para erradicar la pobreza Mundial hacia el año 2015, todos ellos ratificados con alto interés y acción estratégica de carácter global, como marco para la medición de los progresos en materia de desarrollo.

  13. Elementos del sistema electoral del Congreso Mexicano

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    Aldo Medina García

    2013-08-01

    Full Text Available El presente artículo es un estudio de los componentes del sistema electoral, diseñado por el legislador mexicano para integrar al parlamento federal. Estudio desarrollado a sabiendas de la importancia que reviste el sistema electoral como un medio que permite a los ciudadanos convertir su voto expresado en las urnas en escaños a favor de determinado candidato o partido. En dicho análisis tomamos en cuenta la evolución constitucional del sistema electoral mexicano, la participación de las fuerzas minoritarias en la integración del Senado y de la Cámara de Diputados, la división que se hace del territorio en circunscripciones electorales, la barrera electoral que se fija a los partidos políticos para acceder a la representación en el Parlamento, la fórmula de asignación que se aplica a la votación obtenida, para finalmente concluir que el sistema electoral mexicano es esencialmente mayoritario aun cuando se vista de proporcional.

  14. Castillo del Real. Olocau

    OpenAIRE

    AUÑÓN VALLEJO, JONATAN

    2012-01-01

    El objetivo que se quiere alcanzar con este proyecto es el de realizar un estudio lo más cercano posible del Catillo del Real, de manera que se pueda conocer su origen, su evolución a lo largo de la historia, así como las diferentes técnicas y sistemas constructivos utilizados en su construcción. Auñón Vallejo, J. (2011). Castillo del Real. Olocau. http://hdl.handle.net/10251/14244. Archivo delegado

  15. La Representabilidad del Genocidio

    OpenAIRE

    Cardona González, Lorena

    2012-01-01

    El presente artículo intenta hacer una aproximación histórica y analítica al fenómeno del Genocidio, sus implicaciones sociales y culturales que dieron como resultado la reformulación analítica y conceptual de hechos que hasta entonces superaban el conocimiento y la moral humana. De este modo, se hace un trayecto histórico de la paulatina aparición del asesinato masivo como practica de Estado, enmarcado en las experiencias del genocidio armenio y el alemán. A su vez, se hace una mirada sobre ...

  16. Significado presente del CSIC

    OpenAIRE

    Garrido Gallardo, Miguel Angel

    2000-01-01

    Not available

    Este artículo, elaborado en 1999, ofrece una panorámica de la realidad del Consejo Superior de Investigaciones Científicas en la actualidad. Repasa su organización, su volumen de publicaciones, sus indicadores de productividad, su capacidad de obtener recursos y, en suma, su lugar en el conjunto del sistema español de Ciencia y Tecnología, considerado en sí mismo y en relación con la Universidad. Como conclusión del repaso de datos, se afirma que, aunque la fó...

  17. Tratamiento del pie equino

    OpenAIRE

    Robles, Fernanda

    2012-01-01

    El pie equino varo es una patología frecuente en los pacientes con Encefalopatía crónica no evolutiva (ECNE).Se observó que existe una mayor frecuencia en el sexo masculino. Se realizó un estudio descriptivo, comparativo y secundario, durante el periodo de septiembre del 2006 a septiembre del 2011, con un total de 125 pacientes con Ecne, de los cuales se encontraron 101 con pie equino varo congénito. Objetivo: observar los resultados obtenidos en la rehabilitación del pie equino, en niños de ...

  18. Del Pasadismo al Futurismo

    OpenAIRE

    Agudo-Martínez, M. J.

    2003-01-01

    Uno de los habituales prejuicios a la hora de abordar el análisis del movimiento futurista, al igual que sucede con el constructivismo, es la consideración del contexto político en el que se desarrollaron ambas vanguardias. Sin embargo, y dejando a un lado un enfoque del arte con finalidad política de signo diverso, habría que insistir en el hecho de que posiblemente sean tanto el futurismo italiano como el constructivismo ruso, los movimientos que con mayor entusiasmo se manifestaron, en un ...

  19. Preferencias del Turista

    Directory of Open Access Journals (Sweden)

    Jose Luis Leiva Olivencia

    2015-01-01

    Full Text Available Actualmente existen aplicaciones orientadas al turismo basadas en realidad aumentada, pero no integran técnicas de recomendación. Este articulo describe RAMCAT (Realidad Aumentada Móvil Contextual Aplicada al Turismo un modelo de guía turística, que recomienda puntos de interés, teniendo en cuenta factores como preferencias personales y atributos contextuales. Se presentan los componentes teóricos de la arquitectura propuesta, así como sus características, destacando la integración de diferentes sistemas de recomendación, que permiten añadir nuevos motores en el futuro. El articulo se centra en describir sus funcionalidades y el modulo correspondiente al sistema de recomendación basado en el perfil del turista. Otra característica importante del sistema propuesto es la retroalimentación del mismo mediante calificaciones del turista y su trazabilidad.

  20. Carta del Editor

    Directory of Open Access Journals (Sweden)

    Luis Eladio Proaño

    2015-01-01

    Full Text Available La millonaria contratación del futbolista David Beckham, un fenómeno del mercado, ha provocado cuestionamientos a los que se busca respuesta. Es tema de análisis el por qué el betseller "Harry Potter" ha causado tanta conmoción en la opinión pública. Respecto al periodista cibernético, se señalan los contornos del presente y atisban las posibilidades del futuro de esta nueva profesión. El tratamiento de los mitos de la prensa, los temores de la Ley mordaza venezolana y la brutalidad de los video juegos e Internet son temas de enorme interés. Se comenta las pocas veces que la prensa reflexiona sobre la comunicación corporal y la anorexia.

  1. Los muertos del Floreanismo

    Directory of Open Access Journals (Sweden)

    Enrique Ayala Mora

    2008-06-01

    Full Text Available El artículo analiza el crimen político durante las primeras décadas de vida de la República del Ecuador. Específicamente centra su estudio en el período dominado por la figura de Juan José Flores, primer presidente del Ecuador. La inestabilidad política, la precariedad de las alianzas entre las élites regionales, la crisis económica generada por las guerras de Independencia, las conspiraciones y la violencia que caracterizaron al período de surgimiento de las repúblicas andinas hicieron del crimen político un “vicio de nacimiento”. El asesinato del general Antonio José de Sucre, la muerte de los miembros de la sociedad El Quiteño Libre, el homicidio de Juan Otamendi, entre otros, hicieron patente esta característica.

  2. Niveles del aprendizaje organizacional

    OpenAIRE

    Garzón Castrillón, Manuel Alfonso

    2005-01-01

    En la propuesta de modelo de aprendizaje organizacional (AO), la segunda variable se denomina niveles del aprendizaje organizacional ; los niveles de aprendizaje que contemplamos para nuestra investigación son: individual, de equipo, organizacional e interorganizacional.

  3. La escritura del Yo

    Directory of Open Access Journals (Sweden)

    Patricio Landaeta Mardones

    2013-11-01

    Full Text Available Si la creación de una imagen fidedigna del mundo fue la condición de la conquista cognitiva y económica de la tierra, las imágenes mediáticas circulan hoy en día a la manera de un montaje que organiza los sujetos como elementos de un territorio. En esta presentación abordaremos el cruce entre estos dos hechos, entre la escritura del mundo y la de los sujetos, a partir de la idea de Fabulación para mostrar otra escritura del mundo y del yo, leyendo textos e imágenes de la Primera buena Corónica y Buen Gobierno de Felipe Guaman Poma de Ayala.

  4. Consideraciones alrededor del Libro del Almismo, el Libro del Pensar.

    Directory of Open Access Journals (Sweden)

    MartaLucía Tamayo Fernandez

    1999-12-01

    Full Text Available

    La doctora MarthaLucía Tamayo comparte muchas inquietudes alrededor del Libro del Almismo, el Libro del Pensar; de dónde salió ese nombre; de juntar en medicina y en genética a tres escritores como lo son Jorge Luis Borges, Macedonio Fernández y Julio Cortázar. Su conferencia dice así:

    El término almismo fue ideado por Macedonio Fernández porque defendía mucho el ensimismamiento y el pensamiento hacia el interior, mirar hacia adentro; cada uno somos un “sí mismo” que nos hace diferentes aunque al mismo tiempo podemos ser iguales. Todos tenemos esa parte interior que la medicina debe trabajar y que no puede olvidar.

    “El Libro del Almismo, el libro del pensar” nos lleva a replantear y a repensar un poco la medicina que queremos, una medicina vuelta a pensar.

    Quiero contarles la historia de cómo se llegó a este libro y por qué y para qué se sigue trabajando en estos temas: Después de mi internado y de un trabajo un poco triste de rural, volví al Instituto de Genética y a la Universidad Javeriana en donde encontré al doctor Bernal y un espacio que estaba buscando para esa medicina diferente que quería, con un grupo de personas que me permitía no sólo ver la medicina sino ver muchas otras cosas más; había espacio para la literatura, para Mafalda, para hablar de niños, de locos, había incluso tiempo para hablar de medicina dentro del golf, de carros antiguos y de todo eso fui aprendiendo.

    Eso era lo que estaba buscando. Una medicina que diera espacios diferentes, que fuera más humanizada. Rápidamente me ubiqué y me quedé! No me arrepiento en lo absoluto de haberme quedado porque fue, ha sido y sigue siendo, una experiencia enriquecedora, de muchas vivencias importantes. Sabía exactamente dónde estaba y sabía que había que seguir rápido y había que trabajar muchos aspectos de esa medicina que estábamos buscando y de esa genética especial.

    Rápidamente empezamos a trabajar

  5. Actualidad del relativismo cultural

    OpenAIRE

    Sánchez Durá, Nicolás

    2013-01-01

    Este ensayo tiene tres propósitos. En primer lugar, propone examinar las relaciones entre etnocentrismo y relativismo. El etnocentrismo puede tomar tres formas distintas: a saber, la de una universalidad impostada, la del exotismo y la de un particularismo narcisista exacerbado. El relativismo cultural es una postura que asume la inconmensurabilidad de los conceptos y valores que deben ser considerados como válidos dentro de las imágenes del mundo definidas. En segundo lugar, se argumenta que...

  6. el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Carlos Humberto Ortiz

    2007-01-01

    Full Text Available Este artículo se enfoca en la identi- ficación de aquellos factores estructurales que explican la pérdida de dinamismo económico de largo plazo en Colombia y, en particular, en el Valle del Cauca. Se examina la competitividad del Valle en relación con Colombia y con el resto del mundo. Se cuestiona la insistencia en una estrategia exportadora como dinamizadora del desarrollo económico. Se identifica que una gran parte de la población está excluida de los beneficios del desarrollo económico. Para construir un modelo de desarrollo que incluya a esta población se recomienda recuperar la senda de la industrialización, invertir en el capital humano (educación de alta calidad, salud, salubridad y nutrición, e invertir en infraestructura. La participación del Estado en estas inversiones sociales es necesaria para disminuir la desigualdad y aumentar el crecimiento económico.

  7. Espectroscopia del Cometa Halley

    Science.gov (United States)

    Naranjo, O.; Fuenmayor, F.; Ferrin, L.; Bulka, P.; Mendoza, C.

    1987-05-01

    Se reportan observaciones espectroscópicas del cometa Halley. Los espectros fueron tomados usando el espectrógrafo del telescopio reflector de 1 metro del Observatorio Nacional de Venezuela. Se utilizó óptica azul, con una red de difracción de 600 lineas/min, obteniéndose una dispersión de 74.2 A/mm y una resolución de 2.5 A, en el rango espectral de 3500 a 6500 A. Seis placas fueron tomadas con emulsión IIa-O y dos con IIa-D. Los tiempos de exposición fueron entre 10 y 150 minutos. El cometa se encontraba entre 0.70 y 1.04 UA del Sol, y entre 1.28 y 0.73 UA de la Tierra. Las emisiones más prominentes en el espectro, son las del CN, C2, y C3. Otras emisiones detectadas corresponden a CH, NH2 y Na. Los espectros muestran un fuerte continuo, indicando un contenido significativo de polvo. Se detectó mayor intensidad del contínuo, en la dirección anti solar, lo cual es evidencia de la cola de polvo.

  8. Inventario nacional del uso actual del agua

    OpenAIRE

    Oficina Nacional de Evaluación de Recursos Naturales

    1984-01-01

    Establece como se emplea el agua en el Perú, teniendo en cuenta el tipo de uso, consuntivo y no consuntivo, discriminando según sea el destino: agrícola, pecuario, poblacional,industrial, minero, energético y pesquero, así como su localización geográfica; ello con la finalidad de que sirva de información básica para la planificación del desarrollo.

  9. Gerencia del cuidado-gerencia del servicio

    Directory of Open Access Journals (Sweden)

    Marta Palmet Jiménez

    2016-01-01

    Full Text Available La gerencia de este siglo debe estar plenamente identificada con la administración para planear, organizar, decidir y obtener resultados definidos, evaluados y alcanzados a través de las personas. Para poder gerenciar el cuidado se debe saber administrar. El objetivo de enfermería es cuidar; el objetivo de la gerencia es la conducción de la producción de bienes o servicios en las organizaciones. La gerencia del cuidado implica: motivación, creatividad, responsabilidad y ética por parte del cuidador y de quien cuida, claridad de actitud frente al ser y al qué hacer por parte del cuidador. Se puede concluir que la gerencia (administración, el cuidado (producto de calidad, el servicio (valor intangible, querer servir son un trinomio que deben ir de la mano de manera integrada para el logro de los objetivos propuestos por la organización de salud y de enfermería.

  10. Determinantes del ingreso y del gasto corriente de los hogares

    OpenAIRE

    Muñoz C., Manuel

    2004-01-01

    Este ensayo de investigación empírica analiza los determinantes del ingreso y del gasto en los hogares colombianos. Utilizando un modelo del ciclo de vida con datos de la encuesta de hogares de 1994 y 1995, muestra que el comportamiento del ingreso está afectado principalmente por las características demográficas del hogar y los rasgos socio ocupacionales de sus miembros. El comportamiento del gasto está determinado ante todo por el ingreso y, en menor medida, por las características sociales...

  11. Las fluctuaciones del nivel del mar durante el Cuaternario

    OpenAIRE

    Pousa, Jorge Lorenzo; Isla, Federico Ignacio; Schnack, Enrique Jorge

    2002-01-01

    Los cambios del nivel del mar han ejercido una fuerte influencia en la evolución del planeta y en la historia de la humanidad. En una escala de tiempo geológico, las variaciones de los niveles oceánicos han dejado un registro ampliamente distribuido en la forma de depósitos sedimentarios. El descenso del nivel del mar durante la Ultima Glaciación, que alcanzó unos 120 metros hace 18.000 años, permitió la emergencia del estrecho de Bering y la migración humana desde Eurasia hacia América. Se e...

  12. La imagen del pase.

    Directory of Open Access Journals (Sweden)

    Hernando Bernal.

    1999-11-01

    Full Text Available A partir de un texto del poeta Octavio Paz llamado «La imagen», se busca proseguir la equivalencia entre las imágenes de la poesía y la función que ellas tienen para el poeta, y el fantasma fundamental y su función para el analizante que está en el momento del pase. Se parte de la idea de que la poesía busca entrar en el ser así como el psicoanálisis tiene como finalidad apuntar al corazón del ser del sujeto. Se hace entonces una distinción del concepto de «ser» para el psicoanálisis, haciendo alusión también al discurso de la filosofía. Esclarecido el sentido de lo que es el «ser» para el psicoanálisis, se aborda de lleno – entre otras cosas, relacionadas con la experiencia del pase específicamente- la equivalencia entre la definición que hace Octavio Paz de «La Imagen» y el momento del pase en el análisis de un sujeto, imagen que, al igual que el mito para la filosofía, las leyes para la ciencia y el matema para el psicoanálisis, se constituyen en los instrumentos con los que cada una de estas disciplinas horadan en lo real.

  13. del Estado Aragua

    Directory of Open Access Journals (Sweden)

    Joselys Cintia Zerpa

    2008-01-01

    Full Text Available Diagnostica la situación actual de los bienes que conforman al patrimonio histórico-cultural del Municipio Zamora, Estado Aragua, Venezuela. La Investigación es descriptiva y de campo, comprendió la elaboración de un inventario de los bienes inmuebles, festividades religiosas y manifestaciones artesanales del municipio. Se estudiaron la condición física y uso actual de estos bienes y los planes y proyectos existentes. Analizó el marco normativo que los rige. Se obtuvo la opinión de los representantes de organismos públicos relacionados con la actividad turística del Municipio, de los visitantes, cronistas e historiadores. Aportes: La mayoría de los bienes se encuentran en buen estado de conservación, Las manifestaciones culturales, festividades y la artesanía se desarrollan periódicamente pero no son aprovechadas turísticamente, Se determinó que existe un marco normativo para tales bienes y No existen propuestas actuales referentes a estos bienes. Se reflejó el interés de los sectores institucional y privado para la incorporación de estos bienes a la oferta turística del Municipio y del Estado

  14. APOSTILLAS ACERCA DEL POSTRABAJO

    Directory of Open Access Journals (Sweden)

    Arturo Torrecilla

    2000-01-01

    Full Text Available El más reciente debate en torno al postrabajo transforma la herencia de los dos ciclos que le precedieron desde los años setenta. El primero se correspondía con la crítica de la división social y técnica de labores informada por una filosofía de la alienación o bien por una rectificación de la arquitectónica marxista pero salvaguardando la promesa laborista del buen trabajo. El segundo ciclo hacía eco del rechazo a las cadenas de montaje fordistas y se abría al horizonte de la abolición del trabajo salarial, manteniendo sin embargo el abolengo del sujeto unitario de la historia. La presente escena asume una densidad mayor, producto del encuentro entre las nuevas tecnologías informacionales, las discusiones en el ámbito de la sociología y la antropología, de la tecnología y la ciencia, junto al dueto que inaugura el posmodernismo.

  15. Apostillas acerca del postrabajo

    Directory of Open Access Journals (Sweden)

    Arturo Torrecilla

    2000-04-01

    Full Text Available El más reciente debate en torno al postrabajo transforma la herencia de los dos ciclos que le precedieron desde los años setenta. El primero se correspondía con la crítica de la división social y técnica de labores informada por una filosofía de la alienación o bien por una rectificación de la arquitectónica marxista pero salvaguardando la promesa laborista del buen trabajo. El segundo ciclo hacía eco del rechazo a las cadenas de montaje fordistas y se abría al horizonte de la abolición del trabajo salarial, manteniendo sin embargo el abolengo del sujeto unitario de la historia. La presente escena asume una densidad mayor, producto del encuentro entre las nuevas tecnologías informacionales, las discusiones en el ámbito de la sociología y la antropología, de la tecnología y la ciencia, junto al dueto que inaugura el posmodernismo.

  16. La universidad del futuro

    Directory of Open Access Journals (Sweden)

    FERNANDO SANCÉN CONTRERAS

    2013-01-01

    Full Text Available El trabajo señala la necesidad de reconstruir la Universidad, dado el dinamismo que muestra la ciencia y la sociedad, pues trae consigo cambios sustanciales en la visión del mundo y en el aumento del poder del hombre sobre la naturaleza. Se analizan los supuestos epistemológicos de la universidad tradicional y se propone una nueva explicación del conocimiento humano, enfatizando el conocimiento científico. Postula una docencia fundada en las propiedades de la ciencia, cuyo método inductivo basado en los paradigmas vigentes: analítico, crítico, pragmático, ofrece una herramienta para la docencia, la investigación y la difusión de la cultura. Se propone una educación centrada en el sujeto que se hace a sí mismo (etopoiética y que insiste en el proceso de auto-creación del individuo y de la sociedad.

  17. Significado presente del CSIC

    Directory of Open Access Journals (Sweden)

    Garrido Gallardo, Miguel Angel

    2000-05-01

    Full Text Available Not available

    Este artículo, elaborado en 1999, ofrece una panorámica de la realidad del Consejo Superior de Investigaciones Científicas en la actualidad. Repasa su organización, su volumen de publicaciones, sus indicadores de productividad, su capacidad de obtener recursos y, en suma, su lugar en el conjunto del sistema español de Ciencia y Tecnología, considerado en sí mismo y en relación con la Universidad. Como conclusión del repaso de datos, se afirma que, aunque la fórmula del CSIC, como organismo nacional e interdisciplinario, no es la única posible, la organización del Estado de las Autonomías, así como la evaluación de los datos con que se cuenta, la hacen vivamente recomendable. No hay, pues, sino que seguir con su desarrollo.

  18. Dalt del tren

    Directory of Open Access Journals (Sweden)

    Jaume Subirana

    2001-11-01

    Full Text Available Ens consta que la saviesa popular hi toca més del que a aquest temps d’enquestes, telèfons mòbils i targetes de crèdit li ve de gust admetre, per això em fa gràcia, en veure la pausada però continuada intrusió de la cultura catalana a Internet, recordar les cançons de quan era petit: “Dalt del tren, tots anem-hi dalt del tren, hi ha lloc per tota la gent”, dèiem, i “El tren pinxo de Banyoles és el més bonic que hi ha, ple de llaunes i cassoles i barrets de capellà”. I resulta que per una vegada a la vida hem pujat, efectivament, dalt del tren que passava per l’estació de Catalunya i en cinc anys hem passat de gairebé res a prou pàgines amb un contingut, a més, apreciable i, sobretot, a un petit teixit de persones i institucions que han entès la importància de la revolució comunicativa que Internet representa i que hi teixeixen i projecten webs amb el convenciment dels conversos.

  19. Las carreras del futuro

    Directory of Open Access Journals (Sweden)

    Luis Piscoya Hermoza

    2011-07-01

    Full Text Available La primera década del siglo XXI ha estado signada por un énfasis en los estudiosde prospectiva, los mismos que, a partir de procesos de complejizacióny articulación de la sociedad planetaria como son la digitalización, el progresivodeterioro del medio ambiente, la necesidad del cambio de la matriz energéticay la globalización del mercado, han ensayado hipótesis para identificar lastendencias que se fortalecerán y profundizarán durante las próximas décadas.Desde el punto de vista metodológico, existen muchas maneras de clasificarlaspara conceptualizarlas y entenderlas mejor. Sin embargo, considerando lanaturaleza de esta edición nos proponemos enfocar directamente aquellas queestán estrechamente ligadas a la formación universitaria.Naturalmente, no pensamos que estamos ante tendencias inevitables en lamedida que epistemológicamente la creencia en leyes históricas deterministases insostenible y la práctica social nos muestra que la construcción del futuroes nuestra responsabilidad y siempre rebasa las mejores previsiones.

  20. Componente Cultura del Agua del PMGRH: plan de trabajo

    OpenAIRE

    Autoridad Nacional del Agua; Proyecto de Modernización de la Gestión de Recursos Hídricos

    2012-01-01

    Describe el plan de trabajo del Componente Cultura del Agua del Proyecto de Modernización de la Gestión de Recursos Hídricos (PMGRH) en relacion a dos aspectos estructurales del proyecto: 1. Mejora de la capacidad de la Gestión Integrada de Recursos Hídricos (GIRH) a nivel nacional y 2. Fortalecimiento de las capacidades de GIRH en las cuencas.

  1. En busca del concepto de gerencia del cuidado

    Directory of Open Access Journals (Sweden)

    Ligia Teresa Mora-Delgado

    2005-12-01

    Full Text Available Este articulo, presenta los conceptos de gerencia del cuidado de enfermería, desarrollado por las enfermeras profesionales que laboran en le Empresa social del estado Hospital Universitario Erasmo Meoz de las Ciudad de Cúcuta, desde su desempeño en la asistencia, administración y docencia. Se pretende además precisar los elementos gerenciales, sociales, humanísticos y éticos que deben hacer parte del concepto de gerencia del cuidado.

  2. LA PERSISTENCIA DEL SUBALTERNO

    Directory of Open Access Journals (Sweden)

    John Beverley

    2002-01-01

    Full Text Available Este trabajo es el texto literal de una ponencia presentada en un panel sobre los estudios culturales latinoamericanos en el congreso de LASA en 2001 en Washington DC. Representa la posición desarrollada en el trabajo colectivo del llamado Grupo de Estudios Subalternos Latinoamericano, desde nuestra fundación en 1992 hasta la disolución del grupo en 2001, que sirve como pretexto introductorio para la ponencia. Los otros participantes en el panel eran Walter Mignolo, representando los estudios poscoloniales, Néstor García Canclini y John Kraniauskas, representando los estudios culturales, y Nelly Richard representando la llamada crítica cultural. El trabajo dialoga y debate con cada una de estas posiciones respectivamente desde el punto de vista específico de los estudios subalternos. Concluye con un llamado a una crítica del saber académico en sí.

  3. Acalasia. Controversias del tratamiento

    OpenAIRE

    Restrepo P, Antonio J; Rey T, Mario H; Garzón O, Martín A; Farfán Q, Yesid A; Molano V, Juan C; Marulanda, Juan C; Lizarazo, Jorge I

    2007-01-01

    La acalasia es un desorden motor del esófago caracterizado por pérdida de la peristalsis esofágica con falta en la relajación o relajación incompleta del esfínter esofágico inferior (EEI) (1). La causa exacta de este trastorno es desconocida. Los síntomas más comunes son disfagia, regurgitación, pérdida de peso y dolor torácico (2). La manometría esofágica es el principal método diagnóstico, mostrando aperistalsis del cuerpo esofágico con aumento de la presión, falta de relajación o relajació...

  4. Procedimiento Del Triple Fin

    Directory of Open Access Journals (Sweden)

    Oscar L. Bellido Aguilera

    2008-01-01

    Full Text Available Presenta un procedimiento novedoso basado en un método dialéctico - sistémico - integrador, que facilita la precisión de los fines u objetivos más generales de un proceso de desarrollo comunitario o de otros procesos de cambio deseados (un proyecto sociocultural, una investigación social, un proceso de mejoramiento organizacional, etc.. Su importancia radica en que los fines, según Marx, son una guía que rige como una ley la actuación del hombre y determinarlos es parte esencial del planeamiento del cambio. Se trata de un asunto aparentemente simple, sin embargo, en la práctica es mucho más problemático de lo que comúnmente se cree.

  5. Efecto del silicio y plaguicidas en la fertilidad del suelo y rendimiento del arroz

    OpenAIRE

    Furcal-Beriguete, Parménides; Herrera-Barrantes, Alejandra

    2013-01-01

    Efecto del silicio y plaguicidas en la fertilidad del suelo y rendimiento del arroz. El objetivo de este trabajo fue evaluar el efecto del silicio en la fertilidad del suelo, la incidencia de enfermedades y plagas insectiles, el rendimiento y la calidad de granos del cultivo de arroz. El estudio se realizó en La Vega, Florencia, San Carlos, Costa Rica entre mayo y octubre en los años 2010 y 2011, en el mismo lote con la variedad CR 4477. Se establecieron cinco tratamientos: silicio al suelo, ...

  6. Storia del pensiero matematico

    CERN Document Server

    Kline, Morris

    1999-01-01

    Costruita con l'intento di presentare le idee oltre ai protagonisti della matematica, questa storia ha il duplice pregio dell'esaustività e della chiarezza. Essa prevede infatti vari livelli di lettura: lo specialista vi trova una messe di dati, fonti e spunti di ricerca, mentre lo studente ha a disposizione un formidabile strumento di consultazione e sintesi. L'arco temporale coperto è vasto: dalla Mesopotamia a Euclide, da Fibonacci all'invenzione del calcolo infinitesimale, da Gauss a Poincare, con un'appendice dedicata agli sviluppi piu recenti scritta appositamente per la prima edizione italiana del 1991, nei «Manuali» Einaudi.

  7. La escritura del quechua

    OpenAIRE

    Authier, Martine du

    2015-01-01

    La mayor fantasía ha acompañado siempre la transcripción del quechua. El primer intento de sistematización fue el sistema de la Paz, en 1953. Sin embargo, no existe en el comercio un diccionario satisfactorio en lo que se refiere al quechua del Cusco y, prácticamente, nada se edita en quechua, fuera de algunos trabajos antropológicos bilingües. Bajo la égida de la UNESCO, la Academia Peruana de la Lengua Quechua, que tiene su sede en el Cusco, ha colaborado en un diccionario de doce de los tr...

  8. El lenguaje del cerebro

    Directory of Open Access Journals (Sweden)

    Antonio Ibáñez Molina

    2011-04-01

    Full Text Available La introducción de nuevas técnicas de análisis de ritmos EEG en estudio de la comprensión del lenguaje permite explorar esta habilidad humana desde una perspectiva de integración de grupos de redes neuronales. Los ritmos de disparo neuronal que generan estos grupos pueden conectarse por sincronía formando unidades funcionales transitorias distribuidas en diversas áreas del cerebro. En esta revisión comentamos algunos de estos ritmos y su relación con el lenguaje.

  9. Plasticidad del sistema nervioso

    Directory of Open Access Journals (Sweden)

    L. M. Garcia-Segura

    1976-06-01

    Full Text Available En este trabajo se revisan los conocimientos más recientes sobre el fenómeno de la plasticidad del sistéma nervioso, tanto a nivel morfológico como a nivel fisiológico y molecular. Se estudian los cambios morfólogicos y fisiológicos de las neuronas frente a la experiencia. Tambien se considera la adaptación molecular del sistéma nervioso a la información que recibe como la base de todo tipo de plasticidad.

  10. Las causas del desempleo

    OpenAIRE

    García Balbás, Salomé

    2014-01-01

    En este documento vamos a tratar de dar respuesta a la siguiente pregunta: ¿cuáles son las causas del desempleo? Para ello realizaremos un repaso de las principales teorías económicas del desempleo llegando a la conclusión de que existe una causa fundamental que lo genera: la rigidez de los salarios a la baja. Consideramos el desempleo como la existencia de un exceso de oferta en el mercado de trabajo y haremos alusión, únicamente, a la existencia de desempleo involuntario. La exposición de l...

  11. Inventario del Archivo del conde de Bornos

    Directory of Open Access Journals (Sweden)

    Pedro Antonio Porras Arboledas

    1995-01-01

    Full Text Available Mi primer contacto con esta Casa se remonta a algunos años atrás, cuando me Mamó la atención un documento muy interesante, publicado a comienzos del presente siglo por el ilustre erudito ubetense don Alfredo Cazaban, por el que los Reyes Católicos hacían merced a su secretario y jefe de la artillería real durante la Guerra contra Granada, Francisco Ramírez de Madrid, personaje madrileño de origen cántabro, de una heredad en término de Jaén —el cortijo de Bornos— por sus grandes esfuerzos en la conquista de las plazas, hasta el momento inexpugnables, de Cambil y Alhabar. Posteriormente, al realizar un estudio sobre el régimen señorial en el Reino de Jaén, intenté localizar los archivos de las diferentes casas nobiliarias asentadas en esta provincia, gracias a lo cual pude saber que la documentación del Condado de Bornos se hallaba en Madrid, bien en la Biblioteca Nacional o en el Archivo Histórico, ya que el actual Conde, el Excmo. Sr. Don Ignacio Ramírez de Haro, así me lo comunicó en marzo de 1983.

  12. Peter A. Florschutz

    Directory of Open Access Journals (Sweden)

    Cleef Antoine M.

    1978-12-01

    Full Text Available El 25 de mayo de 1976 falleció inesperadamente, a la edad de53 años, Peter Arnold Florschütz, eminente briólogo y profesor deBotánica Sistemática en Utrecht (Holanda. Era bien conocido porsus estudios de los musgos de Surinam. Fue coautor del "Index Muscorum", miembro de la comisión de la Flora Neotrópica y tesorero del IAPT.

  13. Competencia Desarrollo del Pensamiento Creativo

    OpenAIRE

    Rodríguez, Eric; Miceli, Francisco; Tiburcio, Georgina; Gómez, Orlando

    2012-01-01

    1. ¿Qué significa la competencia Desarrollo del Pensamiento Creativo? 2. ¿Por qué es relevante que adquiera la competencia Desarrollo del Pensamiento Creativo en mi formación? 3. ¿Cómo aprendo la competencia Desarrollo del Pensamiento Creativo? 4. ¿Cómo aplico la competencia Desarrollo del Pensamiento Creativo? 5. ¿Cómo puedo autoevaluar mi competencia (con miras a un constante crecimiento)?

  14. Ruptura del projecte parental i disposició dels preembrions

    OpenAIRE

    Farnós Amorós, Esther

    2010-01-01

    La tesi doctoral "Ruptura del projecte parental i disposició dels preembrions" analitza els efectes del consentiment a les tècniques de reproducció assistida prestat en el marc d'un projecte parental. La tesi ofereix una resposta als conflictes que enfronten exesposos o exconvivents en relació al destí dels preembrions sobrants d'un cicle de fecundació "in vitro" iniciat durant la relació. Aquests conflictes constitueixen un grup de casos al voltant del qual no hi ha solucions legislatives qu...

  15. La equinoterapia en las distintas alteraciones del desarrollo del menor.

    OpenAIRE

    Chamorro González, Mireya

    2015-01-01

    La equinoterapia consiste en la utilización del caballo como un método terapéutico para rehabilitar a personas con discapacidad. Esta terapia es considerada una gran alternativa para aumentar el autoestima de los que sufren algún tipo de discapacidad, también a través de esta terapia se mejora y fortalece el estado emocional, así del mismo modo ayuda a mejorar la manera de desenvolverse en su entorno social. Esta terapia se realiza a través de la trasmisión del calor corporal del caballo, del...

  16. Gestión del riesgo del cambio (segunda parte)

    OpenAIRE

    Zorrilla Salgador, Juan Pablo

    2004-01-01

    Segunda parte del artículo acerca del uso de futuros sobre el tipo de cambio. Esta continuación abarca estrategias, definiciones, metodología y explicaciones sobre todo lo relacionado con el Ratio de cobertura de los futuros y la aparición del riesgo base.Segunda parte del artículo acerca del uso de futuros sobre el tipo de cambio. Esta continuación abarca estrategias, definiciones, metodología y explicaciones sobre todo lo relacionado con el Ratio de cobertura de los futuros y la aparición d...

  17. del's Proof

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 5. Gödel's Proof - Incompleteness Theorems. S M Srivastava. General Article Volume 12 Issue 5 May 2007 pp 71-84. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/012/05/0071-0084. Keywords.

  18. Marketing Mix del Software.

    Directory of Open Access Journals (Sweden)

    Yudith del Carmen Rodríguez Pérez

    2006-03-01

    Por ello, en este trabajo se define el concepto de producto software, se caracteriza al mismo y se exponen sus atributos de calidad. Además, se aborda la mezcla de marketing del software necesaria y diferente a la de otros productos para que este triunfe en el mercado.

  19. Gerencia del servicio

    OpenAIRE

    Nancy Peña Acosta

    1992-01-01

    Estamos en la era de la pirámide invertida donde el cliente es primero por lo que es fundamental incentivar la calidad desde abajo; hacer que el trabajador defina su misión, sienta que es parte de la compañía para que la satisfacción del negocio realizado sea de todos.

  20. El Juego del Juego

    OpenAIRE

    Carvalho, Nazaré Cristina

    2012-01-01

    DUVIGNAUD, Jean. El Juego del Juego. Santafé de Bogotá, Colômbia: Fondo de Cultura Econômica, 1997.The game gameDUVIGNAUD, Jean. The Game Game. Santafé de Bogotá, Colombia: Fondo de Cultura Econômica, 1997

  1. El helor del cuerpo

    OpenAIRE

    Sánchez-Biosca, Vicente

    1992-01-01

    Ensayo sobre las formas clásicas y modernas de la metamorfosis. En esta figura mitológica se advierte de manera privilegiada la entrada del imaginario científico, biológico y genético en el dominio de las construcciones literarias y cinematográficas.

  2. Carta del Editor

    Directory of Open Access Journals (Sweden)

    Luis Eladio Proaño

    2014-12-01

    Full Text Available La publicación se centra en temas como: Procesos electorales en México e Italia, se analizan los procesos comunicacionales y sus efectos; las infiltraciones de las agencias de seguridad en la actividad periodística en Europa; la radio y la televisión pública en los EE.UU. Para conocer cómo la prensa enfrenta los problemas críticos entre países, esta el caso de Uruguay y Argentina (discrepancia por la planta de procesamiento de papel y la contaminación del Río de La Plata. Otro artículo refiere la difícil relación entre los medios de comunicación y el gobierno de Chávez en Venezuela. Se aborda el caso brasileño para entender el crecimiento de los Observatorios de Medios; otro sobre el crecimiento del "periodismo confidencial" en la web y la prensa gratuita. Se estudia el impacto de la telenovela "pasión de gavilanes". Para quienes interese la penetración del Internet está: "Usos y competencias del weblog en las corporaciones" más otro sobre la lucha sorda que mantienen los gigantes de la autopista de la información Google y Yahoo.

  3. Punctualizaciones del CERN

    CERN Multimedia

    2002-01-01

    "Viene de la pagina anterior. Puntualizaciones del CERN. La valoracion que me merece la aprobacion en el Consejo de Ministros el 24 de mayo de un acuerdo de colaboracion entre el MCYT y el CERN para el proyecto de neutrinos al Gran Sasso es positiva" (1 page).

  4. Software del sistema osteomioarticular

    Directory of Open Access Journals (Sweden)

    Dianelys León Medina

    2015-06-01

    Full Text Available Introducción: la aplicación en la enseñanza de las Tecnologías de la Informática y las Comunicaciones, es una de las líneas que ha trazado el sistema de salud cubano en estudiantes de las ciencias médicas. La anatomía es una de las ciencias que integra la disciplina de Morfofisiología y para facilitar su comprensión resulta necesario el empleo de recursos y estrategias, entre los que puede figurar un software educativo. Objetivo: diseñar un software sobre la anatomía del sistema osteomioarticular de cabeza y cuello para los estudiantes de primer año de la carrera de Estomatología de Pinar del Río. Material y método: se realizó un estudio cualitativo. Para obtener los resultados se utilizó el método materialista dialéctico. Para la dialéctica del desarrollo del proceso estudiado se utilizaron los métodos teóricos, empíricos, el estudio profundo del tema, tipo de plataforma a utilizar y criterios de los especialistas. Para su procesamiento se utilizaron técnicas estadísticas descriptivas e inferenciales no paramétricas. Resultados: debido a la necesidad de fortalecer en los estudiantes las habilidades en la utilización de las tecnologías de la informática y las comunicaciones, se elaboró el software de la anatomía del sistema osteomioarticular de cabeza y cuello "Aprendiendo anatomía" mediante imágenes, videos y textos. Conclusiones: el software constituye un aporte al proceso enseñanza aprendizaje, el cual facilita el trabajo independiente y autopreparación mediante la interactividad con el contenido, retroalimentación y evaluación utilizando medios de enseñanza modernos, lo cual tributa al modo de actuación del futuro egresado.

  5. Historia deldel = History of Padel

    Directory of Open Access Journals (Sweden)

    Bernardino Javier Sánchez-Alcaraz Martínez

    2013-10-01

    Full Text Available El presente trabajo resume la historia del deporte deldel. Existen dos versiones sobre el origen deldel. La primera versión relaciona los antecedentes deldel con los de otros deportes de raqueta como el tenis o el bádminton, siendo su origen común el jeu de la paume francés. Posteriormente, surgen variantes en Estados Unidos como el Paddle Tennis y el Platform Tennis, siendo versiones reducidas del tenis, pero con elementos muy comunes al pádel actual. La segunda versión, aprobada por la Federación Internacional de Pádel, afirma que este deporte nació en México, en 1969, a través del empresario Enrique Corcuera.--------------------------------------------------------------------This research summarizes the history of paddle sport. There are two versions about the origin of paddle. The first version relates the history of paddle with other racket sports like tennis or badminton, and its common origin of the Jeu de Paume French. Later, in in the United States, appear two sports called Paddle Tennis and Platform Tennis, which are reduced versions of tennis sport, but these have lot of common characteristics with paddle. The second version, approved by the International Padel Federation, said the sport was born in Mexico in 1969, through the businessman Enrique Corcuera.

  6. Determinantes del ingreso y del gasto corriente de los hogares

    Directory of Open Access Journals (Sweden)

    Muñoz C., Manuel

    2004-06-01

    Full Text Available Este ensayo de investigación empírica analiza los determinantes del ingreso y del gasto en los hogares colombianos. Utilizando un modelo del ciclo de vida con datos de la encuesta de hogares de 1994 y 1995, muestra que el comportamiento del ingreso está afectado principalmente por las características demográficas del hogar y los rasgos socio ocupacionales de sus miembros. El comportamiento del gasto está determinado ante todo por el ingreso y, en menor medida, por las características sociales del hogar y el gasto de otros hogares con características similares. También examina la influencia de la incertidumbre acerca de los ingresos en el gasto de los hogares para comprobar si estos actúan con motivos de precaución.

  7. Estudio del CH interestelar

    Science.gov (United States)

    Olano, C.; Lemarchand, G.; Sanz, A. J.; Bava, J. A.

    El objetivo principal de este proyecto consiste en el estudio de la distribución y abundancia del CH en nubes interestelares a través de la observación de las líneas hiperfinas del CH en 3,3 GHz. El CH es una molécula de amplia distribución en el espacio interestelar y una de las pocas especies que han sido observadas tanto con técnicas de radio como ópticas. Desde el punto de vista tecnológico se ha desarrollado un cabezal de receptor que permitirá la realización de observaciones polarimétricas en la frecuencia de 3,3 GHz, con una temperatura del sistema de 60 K y un ancho de banda de 140 MHz, y que será instalado en el foco primario de la antena parabólica del IAR. El cabezal del receptor es capaz de detectar señales polarizadas, separando las componentes de polarización circular derecha e izquierda. Para tal fin el cabezal consta de dos ramas receptoras que amplificarán la señal y la trasladarán a una frecuencia más baja (frecuencia intermedia), permitiendo de esa forma un mejor transporte de la señal a la sala de control para su posterior procesamiento. El receptor además de tener características polarimétricas, podrá ser usado en el continuo y en la línea, utilizando las ventajas observacionales y de procesamiento de señal que actualmente posee el IAR.

  8. La pluridimensionalidad del rol del docente hospitalario

    Directory of Open Access Journals (Sweden)

    Marian Serradas Fonseca

    2015-07-01

    Full Text Available Este trabajo es el fruto de la observación y la investigación en la trayectoria personal y profesional de la autora dedicada a la educación de niños y niñas en situación de enfermedad u hospitalización. El objetivo de este ensayo es intentar definir de manera específica, el papel, tareas y competencias que el profesional del ámbito educativo tiene en la atención educativa hospitalaria; haciendo especial énfasis en la importancia de la formación de este profesional abogándose por una preparación que permita brindar una atención educativa de calidad a los niños y niñas en situación de enfermedad u hospitalizados.

  9. ABC del Ajedrez. I

    Directory of Open Access Journals (Sweden)

    Marisel Piñeiro Gomez

    2009-03-01

    Full Text Available La promoción del Ajedrez, su conocimiento y práctica por la población constituye uno de los programas de la Revolución, por tal motivo el presente trabajo está encaminado a proponer un material bibliográfico con variadas posiciones sobre el movimiento-captura de las piezas y los sistemas de notación para los masificadores de Ajedrez del municipio Pinar del Río. En esta investigación se utilizaron variados métodos: teóricos, empíricos y estadísticos, además, como método rector el dialéctico materialista. Constituye una novedad científica porque aporta un material bibliográfico que contiene: la composición,  disposición  e  identificación  del  tablero de  ajedrez;  identificación, colocación, movimiento y captura de las piezas de ajedrez; la promoción del Peón; el valor absoluto de las piezas; los sistemas de notación: descriptivo y algebraico. Se le incluyen más de trescientos gráficos, conceptos que son trabajados de lo simple a lo complejo de manera tal que el masificador de Ajedrez lo utilice en sus clases donde se viabilice el conocimiento gracias a las facilidades que le aporta el material; ofrece algoritmos que le guiarán a elaborar nuevas posiciones, los cuales son inexistentes para este propósito en otras bibliografías; su significación práctica radica en que proporciona, tanto al estudiantado como profesorado, ejercicios de ajedrez sencillos que les permitirá a los primeros para que les sirva en su comportamiento, y a los segundos utilizarlos en su auto preparación; el interés social se halla en que pueden ser utilizados por profesores, personal de apoyo a la docencia,  técnicos  del  INDER,  familiares  de  los  estudiantes  para  ayudarlos;  el interés educativo reside en que a través de esos ejercicios contribuimos al fortalecimiento de valores.

  10. Arco del milenio

    Directory of Open Access Journals (Sweden)

    Adell, Josep Mª

    2005-02-01

    the most significant stages in the erection of the Millennium Arch outside the Palacio de Congresos, venue for the 12th IBMAC.
    These pictures are divided into six chapters: Background, Components, Springline, Piers, Arch, Centring Erection and Removal, and Trimming.

    A lo largo de la historia, el Arco de fábrica ha sido el componente constructivo más característico de la Arquitectura y la Ingeniería desde que después de sus inicios etruscos en la época romana fuera desarrollado adelantándose con ello a la cultura helénica.
    El Arco, desde entonces, viene empleándose como una solución constructiva eficiente para cubrir espacios con materiales que no soportan tracciones. La originalidad técnica del Arco lo ha llevado a imponerse como símbolo de las hazañas bélicas como era el Arco de Triunfo.
    En el cambio de siglo y milenio en el que nos encontramos, un salto técnico fundamental se desvela en este Congreso, el Sistema de Albañilería Integral, que abre la posibilidad de ampliar el campo de aplicación de la albañilería con la incorporación del acero, a través de las perforaciones de las piezas, lográndose por fin armar en las tres direcciones del espacio cualquier muro de fábrica que se desee.
    El Arco del Milenio conmemoró el 12th IBMAC de Madrid, mostrando en él los avances técnicos que el Sistema de Albañilería Integral permite, al tratarse de un arco inclinado en el espacio y, por tanto, el primer arco de fábrica construido fuera de la vertical, mediante fábrica de Ladriflor aparejada a tizón, reforzada con barras y cercos.
    El Arco del Milenio, diseñado por J.M. Adell (Presidente del 12th IBMAC, parte de un cilindro de 14 m de diámetro, inclinado 30º sobre el terreno, y construido con fábrica de ladrillo de un pie de grueso, alternando una hilada de color amarillo de cada seis en rojo. El hueco deja un paso libre de 10 m de lado y 5,5 m de altura. La fábrica está armada regularmente por tendeles con cerchas cada

  11. Determinantes del trabajo infantil y la escolaridad: el caso del Valle del Cauca en Colombia

    Directory of Open Access Journals (Sweden)

    Sebastián Urueña Abadía

    2009-10-01

    Full Text Available Colombia, al igual que la mayoría de países latinoamericanos, consciente de las repercusiones sociales y económicas negativas del trabajo infantil, se ha comprometido en la lucha por la erradicación de este fenómeno. Prueba de ello es la ratificación por parte del gobierno colombiano en el año 2007, del Convenio 182 de la OIT sobre la Prohibición de las Peores Formas de Trabajo Infantil y la Acción Inmediata para su Eliminación. En el plano regional, como parte del Plan de Desarrollo del Departamento del Valle del Cauca 2008-2011, se está implementando actualmente una estrategia territorial de erradicación del trabajo infantil en sus 42 municipios. Considerando este panorama, este trabajo indaga cuáles son los determinantes del trabajo infantil y la escolaridad en el departamento del Valle a partir de los datos de la Encuesta Nacional de Calidad de Vida del año 2003. Para el análisis se emplea un modelo econométrico Probit Bivariado, que permite el estudio conjunto e interrelacionado de decisiones diferentes, en este caso la asistencia escolar y el trabajo.

  12. En defensa del indigenismo

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Huamán

    2011-05-01

    Full Text Available El indigenismo como movimiento literario, cultural, ideológico y políticoconstituye un hito, una referencia obligada de nuestra tradición culturaly literaria nacional. Su debate no se reduce ni limita a las primerasdécadas del siglo XX, etapa privilegiada en forma recurrente en los estudiosiniciales sobre esta corriente. Podemos afirmar, sin temor a equivocarnos,que no hay momento ni periodo, más o menos visible, en elque no se haya evaluado en forma crítica este acontecimiento, el mismoque ha resurgido con otras denominaciones o referencias (regionalismo,andinismo, mariateguismo, humalismo, etc., a lo largo de nuestro procesohistórico, pero imbuidas de la perspectiva inicial. El propósito deeste artículo es hacer una defensa del indigenismo contestando algunasposiciones contrarias como la de Mirko Lauer.

  13. RESPONSABILIDAD DEL ODONTOPEDIATRA

    OpenAIRE

    Guillen B., Celso

    2014-01-01

    La Responsabilidad de la atención del niño, requiere de una formación y preparación universitaria de la Segunda Especialidad en Odontopediatría para manejar organismos en proceso de crecimiento somático y psicológico. Es por eso que con el proceso de la ciencia se ha comprendido la importancia de la atención del niño desde que nace. Es así que se ha creado sistemas integrales de atención odontopediátrica durante los primeros años de vida, debido a la alta vulnerabilidad de contraer las enferm...

  14. Responsabilidad Constitucional del Gobierno

    Directory of Open Access Journals (Sweden)

    Francisco Zúñiga Urbina

    2006-01-01

    Full Text Available El artículo analiza la responsabilidad constitucional del Gobierno y sostiene que es jurídico-política, de lejano cuño penal y administrativo, y el procedimiento empleado para hacerla efectiva es la acusación en juicio político, que es un típico caso de "justicia política". A la responsabilidad constitucional se suman las responsabilidades civil y penal de Derecho Público del Presidente de la República y sus ministrosThis paper analyses constitutional responsibility of the government and sustains that it is political and juridical, of distant penal and administrative inspiration, and that the procedure used for persecution is impeachment in political trials, demonstrating a typical case of "political justice." Added to the constitutional responsibility of the government are the civil and penal responsibilities of the President and minister's public law

  15. Infecciones del tracto urinario

    Directory of Open Access Journals (Sweden)

    K. Andrés Wurgaft, Dr.

    2010-07-01

    Full Text Available La infección del tracto urinario (ITU, con sus múltiples presentaciones clínicas, está entre las enfermedades infecciosas más frecuentes, tanto en pacientes ambulatorios como hospitalizados. El uso del examen de orina completa y de urocultivo debe ser racional. La bacteriuria asintomática no debe ser buscada ni tratada, en parte porque esto favorece el desarrollo de bacterias resistentes a antibióticos. Distintos cuadros clínicos requieren de distintas duraciones de terapia antibiótica, y tanto el exceso de días de tratamiento como su falta deben evitarse. Se requiere investigación en la búsqueda de estrategias más efectivas para prevenir las ITU recurrentes y en el desarrollo de nuevos antibióticos orales para las ITU resistentes.

  16. Las cruces del olvido

    Directory of Open Access Journals (Sweden)

    Carla Fernandes

    2012-08-01

    Full Text Available Les tragiques événements du « mars paraguayen » ont signifié la disparition de l’espoir en la transition démocratique dans laquelle le pays s’était engagé depuis presque une dizaine d’années. Renée Ferrer, poète, dramaturge, auteur de plusieurs recueils de contes et de deux romans, consigne alors le témoignage poétique de ce drame national dans le recueil Las cruces del olvido (2001. Elle a auparavant publié d’autres textes qui peuvent rentrer dans la catégorie de la poésie sociale : c’est le cas en particulier de Viaje a destiempo (1989 dédié aux victimes de la dictature. Las cruces del olvido, dès son paratexte, insiste sur la fonction de témoignage que l’auteur souhaite assigner à ses vers et sur le rôle que ceux-ci peuvent jouer dans la transmission d’une mémoire collective. La voix d’un jeune disparu de ce « mars paraguayen », le dédoublement qu’il subit et travers lequel il évoque son entrée dans la mort et son absence du monde des vivants, rendent possible l’écriture de cette expérience de l’indicible qu’est la disparition.Los trágicos acontecimientos del «marzo paraguayo» significaron la desaparición de la esperanza en la transición democrática que el país está viviendo desde unos diez años. Renée Ferrer, poeta, dramaturga, autora de varios libros de cuentos y de dos novelas, escribe entonces el testimonio poético de ese drama nacional en su poemario Las cruces del olvido (2001. Ya había publicado antes textos que se pueden considerar como poesía social: es el caso de Viaje a destiempo (1989 dedicado a las víctimas de la dictadura. Desde el texto apertural, Las cruces del olvido potencia la función de testimonio que la autora desea conceder a sus versos y el papel que éstos pueden desempeñar en la transmisión de una memoria colectiva. La voz de un joven desaparecido del «marzo paraguayo», el desdoblamiento que sufre y a través del cual evoca su entrada en la

  17. Carta del editor

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    José Sánchez Gutiérrez

    2018-01-01

    Full Text Available La comunicación científica en México vive enormes retos ante la carrera de adaptar sus formas de comunicación a las nuevas tecnologías. No es tarea fácil convencerse de abandonar el papel y la imprenta para apostar por el código abierto. Sin embargo, esto es apremiante debido al retraso que se lleva en comparación con otras regiones.  Un reto muy evidente ha sido comprender el acceso abierto, reconociendo que este permite mayor visibilidad a la ciencia y que ayuda a evitar el plagio.  Razón por la que nos alegra que a partir del número 37, Mercados y Negocios cuenta con el ISSN electrónico, además del impreso

  18. Carta del Editor

    OpenAIRE

    Luis Eladio Proaño

    2015-01-01

    Henos aquí con un nuevo número de RIESED. Después de casi un año de ver la luz, y como lo anticipábamos en la carta del editor que acompañaba al número fundacional, hacer una revista electrónica no ha sido una tarea sencilla. Un año más tarde no podemos sino confirmar esa opinión.Gracias al decidido trabajo de los autores, revisores y miembros del equipo editorial hemos podido hacerlo. El proceso de revisión de los artículos ha merecido un cuidado, dedicación y tiempo especiales, que hicieron...

  19. Sonidos del Silencio

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    Luz Rodríguez Carranza

    2009-12-01

    Full Text Available La novela ha muerto, afirmaba Alberto Moravia, popularizada, anexada y banalizada por el cine, la televisión, la prensa, la sicología y la sociología. Para Carlos Fuentes en cambio - quien cita a Moravia en 1969 – « lo que ha muerto es sólo la forma burguesa de la novela, el realismo » (17. Basta un viaje rápido por la red para verificar, sin embargo, que la víctima goza de buena salud y que no está confinada en la cultura de masas o en las ciencias sociales : el modelo realista del siglo XIX – y particularmente la creación de tipos representativos de una época, sean éstos promediales o excepcionales - constituye aún la principal preocupación de los escritores y críticos literarios del siglo XXI.

  20. del consumidor mexicano

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    Nadia Huitzilin Jiménez Torres

    2013-01-01

    Full Text Available Pese a que el 80% de la población del mundo vive en mercados emergentes y países en desarrollo, como México, la investigación sobre el consumidor de estos países ha sido insuficiente. El objetivo de este estudio es determinar el perfil del consumidor mexicano en función de variables psicosociológicas como el etnocentrismo, la apertura cultural, el patriotismo, el colectivismo y las características demográficas. Con este propósito se recogió la información de una muestra de 274 consumidores, se realizaron un análisis factorial de sus principales componentes y un análisis cluster con el cual se aglomeró a los individuos en tres grupos con diferentes perfiles psicosociológicos y demográficos.

  1. del noroeste murciano

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    Ma. Luz Tudela Serrano

    2006-01-01

    Full Text Available En la Región de Murcia se está realizando un esfuerzo por aumentar la producción de energías renovables en cumplimiento de los objetivos de Kyoto establecidos para España. Paralelamente, la percepción social acerca de las mismas preocupa cada vez más. En este trabajo, los ciudadanos opinan ante la necesidad de promover el uso e implantación de energías renovables en varias poblaciones afectadas del noroeste. Emplazamientos idóneos, la conservación de los valores naturales y paisajísticos del entorno y las necesidades socioeconómicas de la zona se suman a un uso racional de estas energías y un desarrollo tecnológico paralelo para alcanzar un desarrollo sostenible.

  2. Lo siniestro del enigma.

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    Victoria Eugenia Diaz.

    1999-11-01

    Full Text Available En "El nacimiento de la filosofía griega", Giorgio Colli nos muestra una faceta tenebrosa del enigma. El dios Apolo, de naturaleza ilimitada, insondable, caprichosa, plantea al hombre enigmas que lo enfrentan con el sufrimiento y con la muerte. Allí, Edipo se confronta con enigmas enviados por el dios en los que se pone en juego su propia existencia. Tiempo después, en el transcurrir del siglo XX, reaparece una nueva forma de este dios arbitrario y arrogante: el desaparecedor de personas, ese inmoderado que impone moderación, borra con su acto un cuerpo, una imagen, un nombre, y formula un nuevo enigma siniestro que enfrenta otra vez al hombre con el dolor y con la muerte.

  3. Carta del Editor

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    Luis Eladio Proaño

    2015-01-01

    Full Text Available El aparecimiento del periodista digital y la educación superior en su formación, el cine indígena y la resistencia cultural, más los Grammy latinos, son temas protagónicos de este número. Se suman la prensa en el combate de piráticas corruptas, los errores de la comunicación del presidente URIBE en el referendo, el fútbol y las Relaciones Públicas en España, la libertad de prensa encarcelada, el Internet y la sociedad de la Información y México: profesiones emergentes para los comunicadores, completan la edición.

  4. Percepcion multisensorial del sabor

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    Charles Spence

    2010-12-01

    Full Text Available La investigación sobre la integración multisensorial de los estímulos auditivos, visuales y táctiles nos está ayudando a entender el funcionamiento de la percepción del sabor. Este conocimiento está teniendo ya un impacto sobre el diseño de alimentos y bebidas, desde los productos que compramos en un supermercado hasta aquellos que encontramos en los restaurantes con estrellas Michelin.

  5. Estado Nutricional del Yodo.

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    Hernando Vargas Uricoechea

    2015-06-01

    Full Text Available INTRODUCCIÓN: Los Desórdenes por Deficiencia de Yodo son un problema serio de salud pública, con cerca de 2 mil millones de personas a riesgo de padecerlos, pudiendo causar bocio neonatal, cretinismo, retardo mental, hipotiroidismo, entre otros. Estos desórdenes son aún prevalentes, y en algunos casos los esfuerzos para su erradicación se han traducido en aumento del riesgo de exceso poblacional de yodo y autoinmunidad tiroidea. En Colombia, se desconoce el estado real de yodo en la población. OBJETIVOS: Determinar la mediana de la yoduría en población escolar, y de los hábitos del consumo de sal, función y parámetros de autoinmunidad tiroidea, y cociente intelectual. MATERIALES Y MÉTODOS: Estudio basado en la comunidad, de corte transversal. Se evaluaron las variables sociodemográficas, la frecuencia de bocio y los niveles de TSH, anti-TPO, anti-Tg, anti-TSHR, yoduria, test de factor G de Cattell, y hábitos del consumo de sal. RESULTADOS: El consumo de sal promedio persona/día fue de 18,13 g. El 37,9% presentó bocio. 36,1% tenían un valor límite en el cociente intelectual. La mediana de yoduria fue de 510,3 μg/L. El 42,75% tuvo anti-TPO positivos, y el 2,87% anti-Tg positivos. El 10% presentó niveles de TSH elevados. CONCLUSIÓN: En escolares de zona urbana, hay un exceso en la mediana de yoduria, pudiendo explicarse por el alto consumo de sal. La alta prevalencia de autoinmunidad tiroidea y bocio, junto al alto nivel de la TSH, puede ser consecuencia del exceso en la ingesta de sal y de otros factores medioambientales/ hereditarios.

  6. El lenguaje del pensamiento

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    Alberto Andreu Marín

    2017-09-01

    Full Text Available ¿Somos capaces de interpretar las señales eléctricas que genera nuestro cerebro cuando estamos pensando? Lo que a priori parece ciencia ficción comienza a ser factible gracias a los avances recientes en técnicas de registro cerebral y en aprendizaje automático. Nos encontramos en el inicio de una nueva era en lo que al conocimiento del cerebro se refiere.

  7. Fundamentos del saber administrativo

    OpenAIRE

    Paola Podestá Correa; Juan Carlos Jurado Jurado

    2005-01-01

    El presente texto tiene por objetivo delimitar, de manera general, algunos de los conceptos más importantes del saber administrativo; en primera instancia, práctica administrativa y saber administrativo. Estos conceptos están ligados con los que en el texto se denominan fundamentos de la administración, estableciendo consensos sobre algunas expresiones comunes en el lenguaje administrativo, y contribuyendo a la comprensión de estos temas para los estudiantes de los primeros niv...

  8. Carta del Editor

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    Jorge Aguirre

    2015-01-01

    Full Text Available La crisis de la prensa Argentina a efecto del mal manejo de la economía y las finanzas, ocupa el tema central. Pasa revista a tres temas de actualidad: El aumento de cobertura y difusión de la prensa gratuita; los esfuerzos de los "viejos" diarios por cambiar de apariencia y el caso del diario estadounidense TODAY que hace veinte años dio un cambio revolucionario en la forma de hacer periodismo diario. Se analizan también temas como: el "carisma" de los líderes actuales, los acuerdos entre los medios de comunicación y el gobierno de México para la difusión de planes y programas oficiales y el rol de los medios en el proceso de establecimiento del ALCA. Agrega el tema controversial sobre la Ley de radiodifusión privada, vigente desde la época de la dictadura pinochetista. En este mismo campo de la Radio otro artículo señala las normas para "contar las noticias" con impacto e interés.

  9. Carta del Editor

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    Jorge Mantilla Jarrín

    2015-01-01

    Full Text Available En este número, el módulo Dibujos Animados, recoge las experiencias del primer curso realizado por el CIESPAL con apoyo de la UNICEF sobre la producción de programas educativos y culturales que utilizan este recurso como una opción comunicacional. Se trata de nuevas tecnologías aprovechadas en Cuba y que pueden ser aplicadas en nuestros países. El módulo relativo al medio ambiente habla del periodismo ecológico con importante desarrollo en América Latina, tema de actualidad que requiere preocupación por parte de los medios de comunicación. Incluye entrevistas a Gunter Grass y Jesús Polanco. Gabriel Alba adentra a los lectores en una novedosa forma de usar las computadoras. En el módulo Debate se trata la Economía, cultura y comunicación; La publicidad vía televisión, La evolución del merchandising en las novelas brasileñas ¿Exigir Ética solo al periodista?

  10. Los felinos del canciller

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    Marco Palacios

    1988-01-01

    Full Text Available En la introducción a una de las obras más influyentes de la historiografía colombiana de nuestros tiempos, el autor, Luis Ospina Vásquez, advierte ciertas dificultades inherentes al oficio de historiar la economía: "Otros aspectos del tema son difíciles de tratar por otros motivos: no se puede citar, entre las causas del difícil adelanto económico de cierta región nuestra, llamada por la generosidad de la naturaleza a una gran riqueza; el hecho de que en ella la política se haya reducido con frecuencia a una pugna entre grupos de hampones[...] Y en el supuesto de que se pudiera dar tratamiento adecuado a lo que, al fin y al cabo, es cosa tangible, no muy difícil de percibir y de describir, faltaría aun dar entrada a un elemento sumamente importante, pero este sí difícil de captar y de transmitir: la 'atmósfera', las 'atmósferas' sucesivas del país y sus regiones, elemento esencial en la historia de la evolución económica.

  11. El Museo del Oro

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    Efraín Sánchez Cabra

    2003-09-01

    Full Text Available El 22 de diciembre de 1939 el Banco de la República compró un objeto de oro de 777,7 gramos de peso y 23,5 centímetros de altura que dio origen al Museo del Oro. Era un poporo quimbaya, pieza maestra de la orfebrería prehispánica. Un objeto bello bello que levanta su bruñido vientre globular y su cuello coronado por cuatro cuerpos esféricos sobre una exquisita base de filigrana fundida, y parece flotar en un espacio propio. Quien lo contempla no puede menos que asombrarse, deleitarse y sentir admiración por sus artífices. Detrás de la compra del poporo había una clara preocupación oficial por proteger una riqueza que comenzaba a entenderse como parte del patrimonio nacional. Esta motivación se pone de manifiesto en una serie de documentos relativos a su adquisición.

  12. Llanto del adulto

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    Alegría Majluf

    2013-09-01

    Full Text Available Se presentan los resultados de un primer estudio transcultural del llanto del adulto que comprende 30 países, entre los que se encuentra el Perú. Vingerhoets et al. (1997 de la Universidad de Tilburg, Holanda, analizan las causas, tendencia y frecuencia del llanto, emociones y sentimientos que inducen al llanto, diferencias y similitudes entre los países y los sexos. Los autores encuentran que las mujeres tienden a llorar con más frecuencia e intensidad que los varones, advirtiendo que en algunos países las mujeres establecen mayor relación entre la tendencia al llanto y el ciclo menstrual que en otros. The results of a first cross-cultural study on adult crying in 30 countries including Peru are presented. Vingerhoets et al. (1997 from the University of Tilburg have analyzed motives, tendencies and frequency of crying, emotions and feelings that provoke crying, as well as differences and similarities among countries and sexes. Results show that women have a tendency to cry more frequently and intensively than men. It has also been noted that, in certain countries, there is a link between crying in women and their monthly period.

  13. Carta del Editor

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    Luis Eladio Proaño

    2015-01-01

    Full Text Available Artículo de fondo es un ejemplo de una campaña exitosa de Relaciones Públicas realizada para rescatar a Medellín para el turismo, ahora herida de muerte por el narcotráfico. Reinicia el tema sobre el cine, recordando el aniversario del nacimiento de Luis Buñuel. Y sobre el Nuevo Orden Internacional de la Información, Luis Ramiro Beltrán da respuesta a las múltiples interrogantes planteadas en la controversia surgida alrededor del tema. Se da a conocer cómo era el periódico de ayer, de hoy y del futuro frente al desafío de las nuevas tecnologías. Se señala el camino para hacer publicidad en Internet. El Internet y la radio nuevos actores para un mismo mercado. Y para los interesados en la investigación se trata cómo y cuándo hacer sondeos flash y se cierra con el lenguaje periodístico cuándo el dequeísmo es lícito.

  14. comportamiento del consumidor

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    Erico Rentería Pérez

    2006-01-01

    Full Text Available En este artículo se analiza el posicionamiento exitoso de los profesionales, particularmente los jóvenes, a partir de las nuevas realidades del mundo y del mercado laboral, así como la empleabilidad como constructo, estrategias posibles y, finalmente, una discusión sobre falacias y realidades de discursos sobre mercado de trabajo profesional. La reflexión se liga a dos investigaciones, y a redes de discusión en Brasil y Colombia, que reflexionan sobre las implicaciones y requerimientos estratégicos que marcan el ingreso o permanencia en el mercado de trabajo de profesionales jóvenes, y se reconoce que esto afecta a otros tipos de profesionales. La investigación de Rentería (2006ª sobre Empleabilidad arroja información sobre las dos primeras partes. La de Enríquez y Rentería (2006 sobre Estrategias de aprendizaje y empleabilidad informa sobre la tercera. Apoyan la discusión elementos de psicología y comportamiento del consumidor. Se discute la inclusión social y calidad de vida por el trabajo.

  15. Carta del Editor

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    Luis Eladio Proaño

    2015-01-01

    Full Text Available Abre la revista una retrospectiva de la crisis económica, política y social en la que se precipitó Argentina (2001-2002 y el tratamiento que dieron los medios a esta situación. En opinión se describe el significado de los nuevos paradigmas de Internet como: interactividad, personalidad, multimedialidad, hipertextualidad, actualización, abundancia y mediación. Responde a la cuestión de ¿cómo y cuándo en la prensa latinoamericana sigue imperando la prensa amarilla? Recoge en un artículo los factores que más inciden en el éxito o fracaso de una campaña política. Aborda la implantación de una nueva moneda única en la Unión Europea y sus incidencias. Destaca las consecuencias vividas por México tras el ataque terrorista del 11 de septiembre 2001 y analiza el tratamiento que los medios dan a las informaciones procedentes del Tercer Mundo en Europa. Contesta a la pregunta inquietante sobre las posibilidades del liberalismo económico para garantizar o contrarrestar la libertad de prensa y por último se aclara los mitos y realidades que se han tejido alrededor de Windows XP de Microsoft.

  16. Inestabilidad compleja del codo

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    Héctor Gabriel Díaz Carrillo

    2014-08-01

    Full Text Available La inestabilidad compleja del codo es de reciente descripción y controversial en sus resultados; es el estado que se deriva del daño estructural y funcional, producido por la incongruencia de las superficies articulares y las estructuras ligamentosas que estabilizan el codo. Se realizó un estudio descriptivo prospectivo, en el período comprendido entre enero de 2011 y abril de 2013, en una muestra no probabilística de ocho pacientes (diez codos, seleccionados según criterios de inclusión y exclusión. Los objetivos fundamentales del estudio fueron: la actualización de conocimientos para el manejo de la enfermedad y la caracterización de los resultados obtenidos en los afectados por esta dolencia que fueron operados en el Hospital Dr. Ernesto Guevara de la Serna de la provincia de Las Tunas. Se analizaron los datos mediante técnicas estadísticas descriptivas y se realizó la evaluación clínica y radiográfica de los lesionados. El tratamiento se ejecutó según los hallazgos y consistió en: reparación ligamentosa, actuación sobre las partes óseas dañadas y colocación de osteosíntesis diversas. La edad promedio fue de 39,2 años y predominó el sexo masculino. A todos se les practicó reparación ligamentosa, siete cupulectomías y seis aplicaciones de cerclajes anti-distractores. Existieron dos reluxaciones y una sepsis local. La amplitud de movimientos fue aceptable dentro del rango compatible, con una buena función ergonómica; de acuerdo a las comparaciones bibliográficas actualizadas que se realizaron. La fijación y reparación de los estabilizadores del codo brindan buenos resultados funcionales. La sistematización en el manejo de la enfermedad, la detección de complicaciones y el arsenal terapéutico disponible son factores a tener en cuenta

  17. Nuevos usos del cemento

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    Páez Balaca, A.

    1977-04-01

    Full Text Available In this article, the evolution of the different systems of transporting and storing submarine oil and its by-products (petroleum gas and natural gas, is dealt with stressing the importance of the use of concrete boats. Due to the high cost of oil pipelines, we have passed from tanks built on land to prestressed concrete tanks which can be berthed at great depths or anchored to the bottom to keep them afloat, it being possible to unmoor them for transferring them. Transporting and storing liquated gas leads US to see the advantages of prestressed concrete over steel, as the latter becomes brittle at low temperatures, whereas the former's strength increases. The different forms and possible sections are analyzed, stressing the great importance of the solution of the double concrete hull with pearlite insulation. Finally, a study is made of «light concretes », not the classical types used as thermal and acoustic insulation, but the semi-heavy ones made with expanded clay, high quality sand and P-450 cement, which technique is not yet as developed in Spain at might be wished.En este artículo se trata la evolución de los distintos sistemas de transporte y almacenamiento del petróleo submarino y sus derivados (gas de petróleo y gas natural, resaltando la importancia del uso de barcos de hormigón. Debido al gran coste de los oleoductos, se ha pasado de los tanques construidos en tierra firme a los depósitos de hormigón pretensado que pueden estar fondeados a gran profundidad o anclados al fondo para mantenerlos flotantes, existiendo la posibilidad de poder desamarrarlos para su traslado. El transporte y almacenamiento del gas licuado nos hace ver las ventajas del hormigón pretensado sobre el acero, pues éste se vuelve quebradizo a bajas temperaturas, mientras aquél aumenta su resistencia. Se analizan las diferentes formas y secciones posibles, destacando la gran importancia de la solución del doble casco de hormigón con

  18. Enfermedad Diverticular del Colon

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    Gonzalo López Escobar

    1991-06-01

    Full Text Available

    Los divertículos del colon han sido reconocidos por varios observadores desde hace más de un siglo, pero en su mayor parte se trataba de casos aislados, hoy se la considera como la enfermedad del siglo XX, la de la era moderna y de los países industrializados y de avanzada tecnología (5,18,33.

    Según el diccionario de la Real Academia Española (11, divertículo, del latín, diverticulum, quiere decir desviación de un camino; y desde el punto de vista anatómico, apéndice hueco y terminado en fondo de saco. (Gráfica No. 1.

    Goligher (17 lo define como la “posada al borde del camino, probablemente un lugar, a menudo, de mala reputación”.

    Historia

    Según Hackford (18, el proceso fué descrito brevemente por Littre a comienzos del siglo XVIII; pero se le atribuye a Cruveilhier la primera descripción como proceso patológico en 1849, quien, además, mencionó: “encontramos, no rara vez, en el sigmoide, entre las bandas de fibras musculares longitudinales, una serie de pequeños tumores piriformes oscuros, que están formados por hernias de la mucosa a través de brechas en la capa muscular” (17.

    Fleischman en 1815 hizo la primera observación de la enfermedad y empleó el término divertículo (45.

    Rokitansky en 1.849, habló de una enfermedad adquirida y consideró que su causa consistía en la constipación (45.

    Virchowen 1853 describió la perisigmoiditis (45.

    En 1859 Sidney Jones informó de una fístula colo-vesical debida a diverticulitis (5,45.

    Loomis en 1870 describe una peritonitis como resultante de una diverticulitis (45.

    En 1877 Ball describió la anatomía patológica de la enfermedad y presentó dos casos de fístula colovesical debidas a diverticulitis (9. Cripps en 1.888 popularizó la colostomía de desviación como tratamiento para la fístula colovesical(18...

  19. Max Weber o el enigma emocional del origen del capitalismo

    OpenAIRE

    EDUARDO BERICAT ALASTUEY

    2001-01-01

    Se analiza el trabajo clave de Max Weber, La ética protestante y el espíritu del capitalismo, desde la perspectiva de la Sociología de las Emociones. Aunque la inclusión de las emociones de los fenómenos sociales es clave para entender la idea de Weber sobre el dogma de la predestinación, los sociólogos han trivializado el papel de la emoción. Tras detallar la creencia de Weber en que el espíritu del capitalismo parte del conocimiento de que el destino del hombre está predeterminado (la ética...

  20. Sobre el significado del descubrimiento del gen FOXP2

    OpenAIRE

    Longa Martínez, Víctor Manuel

    2006-01-01

    El reciente descubrimiento del gen FOXP2 ha ofrecido la primera evidencia clara de la base genética del lenguaje, mostrando una correlación inequívoca desde la perspectiva genética entre una versión mutada de F0XP2 y los trastornos lingüísticos de diferente tipo sufridos por una familia inglesa, conocida como KE. El objetivo central del presente trabajo es discutir diferentes aspectos relacionados con tal descubrimiento; especialmente, la discusión del significado de FOXP2 con ...

  1. Competitividad sectorial internacional. Caso: sector del cuero y del calzado

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    Diana Carolina Villegas Álvarez

    2007-01-01

    Full Text Available El presente escrito se origina en un trabajo de investigación cuya pretensión fue indagar sobre el nivel de competitividad internacional (C.I, del sector del cuero y del calzado colombiano, mediante la aplicación de indicadores que, a partir de la información estadística de las variables de comercio exterior permiten establecer ciertas relaciones que dan cuenta de la importancia del producto en los mercados de los países de la Comunidad Andina de Naciones (CAN, seleccionados para la comparación.

  2. La impronta del nuevo mundo

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    Rodrigo Lagos Vergara

    1992-05-01

    Full Text Available Cuando nos aprontamos a conmemorar el quinto centenario del Nuevo Mundo, cabe hacer algunas reflexiones acerca de nuestro continente a la luz del lenguaje propio de las artes y la arquitectura a través del tiempo. Hablamos del Nuevo Mundo en la medida que aceptamos, por una parte, la concepción del nuevo espacio generado a partir del encuentro de dos culturas, la precolombina americana y la propiamente europea llegada principalmente a través de España, y, por otra parte, aceptando también que el nuevo continente resulta ser la pieza clave que ayuda definitivamente a configurar un nuevo cosmos que revela al mundo su otro extremo y aquella parte que manifiesta la totalidad en la certeza de que la tierra es un planeta.

  3. Efectos colaterales del voto preferente

    Directory of Open Access Journals (Sweden)

    Luis Diego Brenes Villalobos

    2012-07-01

    Full Text Available El artículo describe la multiplicidad de potenciales efectos que la implementación del voto preferente podría acarrear en el ordenamiento jurídico y el sistema de partidos. La primera parte del análisis se dirige a caracterizar y definir el voto preferencial. En segunda instancia, el estudio comprenderá la revista de los efectos colaterales del voto preferente como modalidad de votación.

  4. El movimiento del software libre

    OpenAIRE

    Prudencio Óscar Mochi Alemán

    2002-01-01

    El objetivo de este trabajo es describir el surgimiento y desarrollo del movimiento de software libre. Para ello se analizan algunas características importantes que dan cuenta del origen y desarrollo del mismo, así como de sus momentos más críticos y sus tensiones, sus desafíos y sus retos. Otra de las grandes inquietudes de este trabajo, es intentar descifrar cómo el movimiento del software libre y Linux, en su versión más conocida, sobrevivieron y se afirmaron hasta llegar a ...

  5. Analisi del decadimento $W -> \\tau \

    CERN Document Server

    Coscetti, Simone

    Questo lavoro di tesi si e' svolto nell'ambito dell'esperimento CMS a LHC, ed in particolare verte sullo studio delle strategie di identificazione off-line del leptone tau, atteso tra i prodotti di decadimento del bosone di Higgs, cosi' come di altre particelle previste in altri modelli teorici. Il canale utilizzato per testare la procedura di identificazione del tau e' il decadimento semileptonico del bosone vettore W. Infine, sulla base dei risultati ottenuti viene presentata una stima quantitativa della sezione d'urto di produzione pp-> W + X

  6. El pie del adulto mayor

    OpenAIRE

    Parodi García, José Francisco

    2005-01-01

    Acta Médica Peruana es una publicación del Colegio Médico del Perú El estudio del pie y sus patologías es un capítulo muy importante de la Geriatría. Las patologías del pie no escapan las características comunes de muchos síndromes geriátricos como son el ser asumidos como "normales para la edad", ser poco valorados, menospreciados, no tratados, con gran impacto sobre la salud en general y la calidad de vida.

  7. El maestro del Pavo Real

    OpenAIRE

    Montalvo Martín, Francisco J

    2013-01-01

    Este trabajo pretende hacer una primera aproximación al Maestro del Pavo Real, un platero barcelonés del siglo XIX que usó como marca personal la silueta de un pavo real visto de frente con la cola desplegada y todo ello dentro de un círculo. Este trabajo pretende hacer una primera aproximación al Maestro del Pavo Real, un platero barcelonés del siglo XIX que usó como marca personal la silueta de un pavo real visto de frente con la cola desplegada y todo ello dentro de un círculo.

  8. LIDERAZGO VISIONARIO: CENTRO DEL CONOCIMIENTO

    Directory of Open Access Journals (Sweden)

    Rafael Pérez Uribe

    2013-07-01

    Full Text Available El gestor del conocimiento es el ser humano. En el mundo como en las empresas es el centro de la destrucción y la creación del conocimiento. Por esta razón en las empresas se deben generar los escenarios adecuados para revertir el conocimiento de las personas y convertirlo en patrimonio de las organizaciones. El papel del líder es vital para la construcción de escenarios adecuados para que los trabajadores se conviertan en auténticos gestores del «knowledge» y esto permita que las organizaciones sean entes permanentes de aprendizaje continuo.

  9. Las aristas del racismo

    Directory of Open Access Journals (Sweden)

    Fredy Rivera Vélez

    2000-01-01

    Full Text Available En el presente trabajo se estudia un ámbito que normalmente se esquiva y se enmascara: Las prácticas racistas. Esta evasión del tema se da en diferentes planos discursivos, y es una práctica, cada vez más frecuente en América Latina, pues aquí se hace de la integración étnica uno de los ejes centrales de la construcción de sus relaciones identitarias y políticas. Se propone, entonces, este trabajo develar la naturaleza y el movimiento de prácticas racistas presentes no sólo discursivamente, en la práctica política, en la práctica laboral, sino que también están presente en nuestra vida cotidiana, bajo nuevas formas y contenidos que se distancian del racismo tradicional e incorpora una nueva gramática racista, una suerte de racismo moderno, no basado en el fenotipo o características físicas como elemento central, sino en un racismo basado en la diferencia cultural, lo cual plantea un plano más excluyente, pues en este planteamiento el “objeto de racismo” no es un objeto de racismo limitado, como en el racismo tradicional, en el cual siempre es utilizado por quien practica el racismo; en el racismo contemporáneo se pretende una ruptura completa y una exclusión total del otro.

  10. Etiche del paesaggio

    Directory of Open Access Journals (Sweden)

    Massimo Venturi Ferriolo

    2015-11-01

    Full Text Available L’etica riflette sui rapporti fra uomo e ambiente. Indaga l’azione dell’uomo. Svela la sua visione della vita e il mondo possibile e accoglie in sé un complesso di norme morali e di costume che identificano un preciso comportamento nella vita di relazione. Si riferisce all’agire dell’individuo in una struttura sociale che lo comprende. Siamo alla ricerca di un’essenza del paesaggio indipendente dalla mera pittura, dalla rappresentazione, dall’immagine sentimentale: dalla natura sia ideale che reale. Prendere coscienza della cosa in sé, anche nei suoi aspetti ideali, significa comprenderne la complessità. Possiamo leggere quindi ogni paesaggio come realtà etica, risultato dell'operosità dell'uomo nella natura, ambito complessivo della vita: nel significato peculiare di progetto del mondo umano, che parte da lontano, da quando l'uomo ha incominciato a trasformare il proprio ambiente naturale per creare i luoghi dell'abitare, modellati con la mano e con lo spirito. La conoscenza dei paesaggi in tutta la loro complessità, a partire dal mondo antico, diventa quindi un nostro obiettivo. Questo significa superare, se non addirittura rovesciare, alcuni luoghi comuni consolidati e storicizzati: la teoria secondo la quale il paesaggio, nella sua dimensione estetica, sarebbe un'invenzione della modernità; il collegamento tra la moderna pittura di paesaggio e la nascita dei concetti estetici; la confusione tra natura e paesaggio, frequente nelle concezioni ecologico- ambientaliste; la tesi lessicale della nascita della coscienza del paesaggio, legata all'esistenza di una parola specifica che lo indichi. 

  11. del paradigma comprensivo

    Directory of Open Access Journals (Sweden)

    María Luisa Bacarlett Pérez

    2008-01-01

    Full Text Available A partir de la distinción planteada por von Wright en su texto ya clásico Explicación y comprensión, se analiza la obra de Giambattista Vico (1668-1744 a la luz de su crítica desarrollada hacia Descartes y la distinción que realiza en tre "crítica" y "tópica". No es aventurado decir que en la propuesta viquiana la actividad propia de la tópica, ligada al uso del lenguaje, la retórica y la elocuencia, se acerca más aquello que von Wright ubica dentro del "paradigma comprensivo"; mientras que la crítica, identificada con el método cartesiano, privilegia la abstracción, la deducción lógica y el análisis matemático; es decir, todo aquello ligado al conocimiento de la naturaleza. La gran diferencia en tre tópica y crítica radica, al final, en el criterio de verdad propio de cada perspectiva: mientras la crítica encuentra la verdad en la exterioridad del mundo natural, en algo que los hombres no hacen; en cambio, la única forma de verdad en el terreno de la tópica es como "verdad hecha" o "verum factum"; es decir, la verdad que nosotros mismos hacemos como agentes históricos, lingüísticos, creadores de cultura, de vida política y social.

  12. La era del youtuber

    OpenAIRE

    Sánchez Arufe, Irene

    2017-01-01

    En el trabajo se analizan los cambios que ha provocado y la recuperación que ha tenido la red social YouTube en la sociedad actual, poniendo como antecedentes la aparición de Internet y el auge de las nuevas redes sociales. También se examinan la figura del youtuber como la creación de una nueva profesión y los aspectos económicos y sociales de este nuevo trabajo. Grado en Publicidad y Relaciones Públicas

  13. El desarrollo del emprendedor

    OpenAIRE

    Arco Juan, Francisco Javier del

    2010-01-01

    En este trabajo pretendemos abordar el desarrollo de las competencias y de las cualidades del emprendedor. Para ello analizaremos como mediante el trabajo en equipo, el liderazgo y la toma de decisiones a la hora de elaborar un Plan de Negocio, el alumno desarrollo todas estas competencias básicas. Además, por supuesto, de la capacidad de emprender un negocio a través de las herramientas básicas para la puesta en marcha de un negocio. No data (2010) UEM

  14. Peter Carravetta, Del postmoderno.

    Directory of Open Access Journals (Sweden)

    Alessandro Carrera

    2010-08-01

    Full Text Available Peter Carravetta, professor of “Italian and Italian American Studies” at SUNY Stony Brook, with an Italian and American education, has put together in his massive Del postmoderno possibly the most complete critical review so far of American academic production from the 1970s to the present. “Postmodern” is the key word of the cultural turn that took place between the 1950s and the 1970s only to meet its death, in Carravetta’s opinion, on September 11, 2001, when the shortlived illusion that h...

  15. A favor del Plagio

    OpenAIRE

    Manuel Arranz

    2007-01-01

    Yo no tengo nada contra el plagio. Ustedes, como lectores, seguramente tampoco. Bueno, tal vez prejuicios. Es lógico que los tengan con tanto artículo condenándolo. Hasta ahora, que yo sepa, nadie ha escrito para defenderlo. Los que sí tienen algo, parece ser, son los autores. Una minoría al fin y al cabo. Ya sé que hay que respetar el derecho de las minorías, pero el asunto del plagio, como tantos otros, deberíamos examinarlo con más detalle, y preguntarnos, por ejemplo, ¿por qué se molestan...

  16. El mundo del postfordismo.

    OpenAIRE

    Lipietz, Alain

    2012-01-01

    La crisis de la relación salarial fordista ha conducido a diferentes regímenes salariales aún en bloques continentales integrados. Característica que se suma a la transformación jerárquica de las economías mundiales ocasionadas por el avance competitivo de los nuevos países industrializados y por la concentración de las relaciones económicas internacionales por bloques continentales. Tales son las características básicas del mundo económico internacional posterior a la guerra fría.Este artícu...

  17. emergencia del trabajo liberado

    Directory of Open Access Journals (Sweden)

    Rocío Gómez Z.

    2008-01-01

    Full Text Available Este ensayo sugiere que habría una inestimable conexión entre el compromiso subjetivo y emocional de los jóvenes usuarios de Internet, que invierten tiempo y deseo en realizar un conjunto variado de obras menores (correos electrónicos, imágenes de sí mismos en Facebook, trozos de música, mantenimiento de la bitácora en la Red, y los malestares del bienestar urbano. Estas obras menores encarnan y objetivan las demandas de trabajo liberado -frecuentemente reprimidas, pospuestas, administradas o reguladas-, que algunos de los nuevos repertorios tecnológicos canalizan y movilizan vigorosamente.

  18. Funciones sociales del folclore

    Directory of Open Access Journals (Sweden)

    Alberto Londoño Álvarez

    1969-07-01

    Full Text Available Con el objeto de estudiar los principales aspectos sociológicos del folclore, empecemos con uno de los problemas más significativos, cual es el análisis de sus funciones que cumple en una sociedad. se trata de un asunto perteneciente al sociólogo, quien, con el propósito de mostrar al folclórogo, que su investigación no es única, porque se refiere a un hecho que pertenece al grupo de los fenómenos sociales.

  19. Trastorno del espectro autista

    OpenAIRE

    Mendoza Mendoza, María Yésica

    2012-01-01

    Se explica qué es el autismo, sus causas, tipos, síntomas, tratamiento, detección temprana, técnicas y programas específicos de intervención. A continuación, se analiza el resultado de unos cuestionarios pasados a los padres que tienen hijos con autismo para identificar y conocer el impacto de dicho trastorno en los miembros que conviven con el paciente diagnosticado de autismo y otras comorbilidades asociadas: ansiedad, presión psicológica y trastornos del estado de ánimo

  20. Les Malalties dels cereals

    OpenAIRE

    Puiggrós i Jové, Josep Maria

    1989-01-01

    En aquest treball es fa una descripció de les principals malalties dels cereals que han estat trobades a Catalunya. Agrupant-les segons ataquin la fulla i espiga: oïdi, rovells, septòries, Rhynchosporium, Helminthosporium, i virus; al coll i tija: Cercosporella, Ophiobolus, Rhizoctbnia i Fusarium o bé les que vénen de la llavor: carbons, càries i Helminthospbrium. A part de la descripció, hom fa esment de les observacions efectuades els darrers anys en els diferents indrets de...

  1. La inutilidad del etnocentrismo

    OpenAIRE

    Vanegas Betancourth, Paula C.

    2017-01-01

    El etnocentrismo como filosofía de poder en el mundo occidental. Ha evitado el exaltamiento de las mezclas culturales como opción de vida. Dándole a las minorías un lugar en los suburbios del conocimiento y de la ciencia. La exclusión de las fuentes de conocimiento primitivo por el hombre contemporáneo. Le permite la sensación de dominio sobre el mismo hombre y sobre la naturaleza. La industrialización le permitió al hombre. Como lo menciona David Dickson: « El supuesto dominio sobre la natur...

  2. Catàleg dels Miridae (Heteroptera) del Massís del Garraf

    OpenAIRE

    Goula Goula, Marta

    1989-01-01

    Per a la redacció d'aquest catàleg, s'aporten dades d'observació pròpia al llarg dels anys 1980-1984, així com les troballes publicades per CUNI (1889a,1889b,1889c,1891) i per RIBES (1978a,1978b,1980,1984). Totes aquestes observacions s'han fet en localitats del Massis del Garraf, que será objecte d'una curta descripció.

  3. LAS NEURONAS DEL SEPTUM LATERAL MODIFICAN LA ACTIVIDAD DE LAS NEURONAS DEL NUCLEO TUBEROMAMILAR DEL HIPOTALAMO

    OpenAIRE

    FARIAS RODRIGUEZ, PAULA ANDREA; FARIAS RODRIGUEZ, PAULA ANDREA

    2012-01-01

    El septum lateral (SL), es un núcleo del cerebro anterior, que, procesa la información sensorial afectiva procedente del hipocampo y dirige sus respuestas, importantes para la supervivencia, hacia las zonas del hipotálamo importantes para la motivación, como lo es el núcleo tuberomamilar del hipotálamo (TMN). El TMN contiene las neuronas histaminérgicas en el cerebro, la cual relacionamos con la vigilia y alerta en conductas motivadas y así puede dirigir y reforzar el comportamiento. El TM...

  4. La superación del modelo del ángel del hogar:

    OpenAIRE

    Hurtado Muñoz, Mónica

    2013-01-01

    La Tesis Doctoral titulada "La superación del modelo del "ángel del hogar". Recuperación de la escritora Leonor Canalejas y Fustegueras (1869-1945)" aborda, en primer lugar, un análisis sociológico de las circunstancias que rodearon a la mujer española en el cambio de siglo en el ámbito social y educativo, en un intento de esclarecer las características propias del contexto en el que la mujer accede a la intelectualidad en general y a la literatura en particular. Esta parte concluye que la cr...

  5. RASGOS GEOGRÁFICOS DEL VALLE DEL RIO AGRIO INFERIOR.

    Directory of Open Access Journals (Sweden)

    Celia Torren

    1993-12-01

    Full Text Available El presente artículo es una síntesis del trabajo "Rasgos Geográficos del Valle del Río Agrio Inferior, el cual es un estudio de base para el conocimiento de la geografía de la región: - apoyando el esfuerzo que está realizando la población del área para lograr una identidad propia y una definitiva integración al contexto provincial; - aportando al proyecto "Rescate Arqueológico en Quili Malal, Neuquén" (subsidiado por CONICET y UNESCO, cuya dirección está a cargo de la profesora Susana Rodríguez de la U.N.C., a través de la confección del mapa geomorfológico del área; y - contribuyendo a los estudios que resultan necesarios ante la construcción de una obra hidroeléctrica de la magnitud de "El Chihuido I", emprendimiento que será llevado a cabo por Agua y Energía eléctrica de la Nación. Los límites del área estudiada fueron establecidos teniendo en cuenta el área del valle inferior del Río Agrio que será completamente inundada por el futuro embalse de la represa "El Chihuido I", a emplazarse 5,5 Km aguas abajo de la confluencia de los ríos Agrio y Neuquén. Además de esta área de afectación directa se tomó también una zona de perilago estrechamente vinculada a la anterior. De esta manera los límites este y oeste quedaron establecidos por la confluencia de los ríos antes mencionados y la localidad de Bajada del Agrio, respectivamente.

  6. del cuerpo femenino

    Directory of Open Access Journals (Sweden)

    Betina Hillesheim

    2005-01-01

    Full Text Available Este artículo discute cómo las prácticas de salud dirigidas a las mujeres construyen determinadas significaciones sobre la salud y el cuerpo femenino, comprendiendo que las prácticas en salud producen determinadas formas de ser, vivir y sentir, y constituyen modos de ser mujer y de ser hombre. Se presentan los datos de una investigación desarrollada en un servicio académico de salud, con mujeres que se realizaron exámenes de prevención de cáncer de útero y mama, entre mayo y diciembre del 2002. La recolección de datos se realizó mediante observaciones de las prácticas de la salud y entrevistas con las usuarias del servicio. En términos teóricos, el punto de referencia fueron los estudios feministas, especialmente autores(as cuyas teorizaciones son postestructuralistas. Se espera que este estudio contribuya con la reflexión sobre las prácticas de salud dirigidas a las mujeres, posibilitando una ampliación sobre lo que se entiende por femenino y, dando espacio a otras formas de ser y de estar en el mundo, además de aquellas que el discurso hegemónico sobre mujeres propone como adecuadas.

  7. Fundamentos del metodo cientifico

    Directory of Open Access Journals (Sweden)

    Badii, M. H.

    2004-01-01

    Full Text Available El objetivo de esta obra no radica en realizar una búsqueda exhaustiva de la literatura en el tema, sino, sentar las bases del método científico, notando los aspectos filosóficos e éticos de la ciencia. Se presentan los conceptos y definiciones fundamentales relacionados con la metodología de la investigación científica. Se maneja el concepto de la toma de los datos válidos como un requisito básico en cualquier trabajo científico. Se pone a disposición del lector un modelo denominado el ECOEE que es una herramienta poderosa para establecer puntos de comparación e discusión entre los resultados de diferentes trabajos científicos. Finalmente, ofrece unas sugerencias de que hacer o no hacer en cuanto a realizar un trabajo de investigación.

  8. RECUERDOS DEL SIGLO XX

    Directory of Open Access Journals (Sweden)

    ASUNCIÓN LAVRIN

    2011-10-01

    Full Text Available Este ensayo hace una revisión de conceptos clave en la educación de la mujer en Hispanoamérica, en la primera mitad del siglo XX, y el debate sobre la educación superior de la mujer. También analiza las ideas de Gabriela Mistral para la educación femenina en su Lectura para mujeres, y las compara con las de la escritora mexicana Rosario Castellanos. Finalmente, hace un llamado por nuevos modelos educativos para la mujer de siglo XXI.Este ensayo hace una revisión de conceptos clave en la educación de la mujeren Hispanoamérica, en la primera mitad del siglo XX, y el debate sobre laeducación superior de la mujer. También analiza las ideas de Gabriela Mistralpara la educación femenina en su Lectura para mujeres, y las comparacon las de la escritora mexicana Rosario Castellanos. Finalmente, hace unllamado por nuevos modelos educativos para la mujer de siglo XXI.

  9. Incorrecciones del habla infantil

    Directory of Open Access Journals (Sweden)

    María del Pino LECUONA NARANJO

    2009-11-01

    Full Text Available En el presente trabajo se pretende dar una visión de algunos rasgos característicos del lenguaje infantil, centrándonos especialmente en el estudio de los niños de 4 a 6 años de edad. Es pues, su finalidad fundamental la descripción y análisis de los rasgos que se pueden observar en la expresión verbal de los preescolares. Las diversas peculiaridades que van a ser objeto de examen se refieren a la emisión de incorrecciones de carácter fonético, morfológico y semántico. El análisis unificado de estos tres factores responde a la consideración de que todos surgen como consecuencia de un proceso de simplificación lingüística originado por un estado inconcluso de desarrollo del lenguaje.

  10. Carta del Editor

    Directory of Open Access Journals (Sweden)

    Jorge Jarrín Mantilla

    2015-01-01

    Full Text Available Comunicación y Género, acopia trabajos que vinculan a la mujer y la comunicación y sus esfuerzos por no ser consideradas inferiores. Del libro a la pantalla, acerca a algunas reflexiones sobre el proceso que lleva del libro a la pantalla por la polémica que despierta la adaptación de las novelas, puesto que muchos señalan que la trama se ve desfigurada. Se agregan varios temas sobre el cine. En "Días de Radio", se plantea el que a pesar de la censura y los problemas económicos que deben enfrentar, las radios populares de América Latina, siguen ganando espacios, de su desarrollo depende una mayor profundización de la democracia. Tema de debate es Estrategias comunicativas en Chiapas y Haití. Se añaden dos entrevistas a un caricaturista brasileño y a un corresponsal de guerra muy prestigiado.

  11. Gerencia del Siglo XXI

    Directory of Open Access Journals (Sweden)

    John Orlando Crissien Castillo

    2013-07-01

    Full Text Available El cambio es más rápido que nunca, la tecnología genera nuevos modelos gerenciales, los mercados se abren, el paradigma de la competitividad y la productividad. Los gerentes modernos estamos expuestos a muchas presiones generadoras de estrés; hecho que, según la OMS (Organización Mundial de la  alud, está entre las tres enfermedades que cobran más muertes en el mundo. EL campo de juego gerencial ha cambiado: por ende la gerencia del siglo XXI requiere un perfil de administrador-gerente diferente. Este nuevo gerente se debe tornar líder y administrador. Las cosas se administran, la gente se lidera, se gerencia. Por esto el gerente líder del siglo XXI se debe formar, capacitar, entrenar en aquellas habilidades-competencias requeridas por este nuevo entorno. Por tal razón debe generar dos sets de competencias: las de gerente integral y el desarrollo de la capacidad directiva.

  12. Carta del Editor

    Directory of Open Access Journals (Sweden)

    Luis Eladio Proaño

    2015-01-01

    Full Text Available Refiere el Informe Nacional de Brasil sobre el Diagnóstico de la Comunicación en América Latina en el que se analizan los más importantes medios de comunicación de ese país. En el artículo de opinión se reflexiona sobre los cambios que sufre la comunicación política en la región como resultado de nuevos protagonistas con nuevos mensajes como: Hugo Chávez, Venezuela, Bucarám, Ecuador y Fujimori, Perú. Describe dos noticias que han llamado la atención: la desinformación en la campaña electoral de los Estados Unidos y el peculiar sistema de comunicación del Presidente Chávez para mantener la popularidad. En cultura para la imagen periodística impresa o Infografía muestra los esfuerzos que la prensa diría del mundo entero hace para competir en cuanto a imagen con la televisión. Se trata la elaboración de los guiones cinematográficos y en Comunicación Institucional se responde a cómo a solucionar los problemas de un banco desde Argentina.

  13. El Gobierno del mal menor

    DEFF Research Database (Denmark)

    Agustin, Oscar Garcia

    2012-01-01

    El Gobierno no aspira a ser bueno ni malo. Se conforma con ser el Gobierno del mal menor, cuyas medidas drásticas y poco populares están destinadas a salvar a los ciudadanos del desastre que no ha llegado todavía pero podría llegar....

  14. Tratamiento del paciente con artrosis

    Directory of Open Access Journals (Sweden)

    Francisco Vargas Negrín

    2014-01-01

    Full Text Available El manejo terapéutico del paciente con artrosis tiene como objetivo disminuir la sintomatología dolorosa e inflamatoria, mejorar la capacidad funcional del paciente y la aplicación de intervenciones terapéuticas eficaces y lo más seguras posibles. Un enfoque centrado en el paciente implica su participación activa en el diseño del plan terapéutico y en la toma de decisiones informadas oportunas en todas las etapas de la enfermedad. La educación terapéutica, la actividad física y el ejercicio terapéutico junto con el control de peso, en caso de sobrepeso u obesidad, constituyen el núcleo central del tratamiento. Los autocuidados individuales y por los familiares son fundamentales en el control del día a día del paciente. El uso de terapias físicas, ayudas técnicas (bastón, etc. y de fármacos tipo analgésicos simples, opioides y antiinflamatorios tiene evidencias demostradas en el control del dolor, mejora la funcionalidad y la calidad de vida del paciente y una clara recomendación de uso en el tratamiento de la artrosis. La cirugía conservadora y la de reemplazo articular se indican en los casos en los que no se logran los objetivos terapéuticos en casos concretos.

  15. El Derecho universal del Trabajo

    Directory of Open Access Journals (Sweden)

    Héctor-Hugo Barbagelata

    2014-01-01

    Full Text Available La idea de un derecho universal del trabajo no es nueva, en realidad es más antigua quela legislación del trabajo y por lo tanto, más antigua que la propia rama del derecho que estudia estas cuestiones.Sí, son nuevos los avances que con ese objetivo se han ido registrando desde fines del siglo pasado.I- Introducción.- II Antecedentes.- II Constitucionalización e internacionalización.- IV Principios y criterios de interpretación del bloque de constitucionalidad.- A Criterio fundado en las condiciones del Estado Social de Derecho; B Principio de complementariedad e interdependencia de todas las normas sobre derechos humanos; C Primacía de la disposición más favorable a la persona humana; D Criterio resultante del principio de progresividad.; E Principio de irreversibilidad o de no regresión. F Principio de autoejecución y autoaplicación..- V Conflictos entre los derechos fundamentales .- VI.- Los principios filosóficos: a La Justicia social ; b La especificidad del trabajo humano; c Reafirmación de la dignidad de la persona humana; VII Conclusiones. 

  16. Taquicardias supraventriculares. Estado del arte

    Directory of Open Access Journals (Sweden)

    Jairo Alfonso Gándara Ricardo

    2016-01-01

    El tratamiento de las taquicardias supraventriculares dependerá del estado hemodinámico del paciente, el cual definirá el requerimiento de terapia eléctrica o tratamiento médico. Se debe hacer una selección adecuada de los pacientes que requieren estudio electrofisiológico y ablación.

  17. Notas del Consejo Editorial

    Directory of Open Access Journals (Sweden)

    Fernando Serpa Florez

    1990-08-01

    Full Text Available

    Merecida Distinción
    Complacidos registrados la señalada distinción de que fue objeto en Hiroshima, Japón, durante la celebración del IX Congreso Mundial de la Organización Internacional a Médicos para la Prevención de la Guerra Nuclear (lPPNW el Académico Honorario Alberto Cárdenas Escovar quien recibió el Premio Albert Schweitzer, en reconocimiento a la meritoria labor que ha cumplido en el campo internacional de la medicina.

    Fernando Serpa Flórez

    Breves de la Academia
    En el número anterior de nuestra revista, por involuntaria omisión no se incluyeron dos señalados acontecimientos, que nos apresuramos a subsanar en la presente edición. Se trata del ingreso a la Corporación de dos distinguidos y muy apreciados Miembros de nuestro Instituto, el Académico correspondiente Joaquín Silva, Profesor de Cirugía y eminente maestro de numerosas generaciones médicas, quien disertó en forma erudita y ponderada sobre el tema “Los albores de la Medicina y Cirugía”. Así mismo tomó posesión como Miembro de Número el actual Presidente del Capítulo de los Santanderes de la Academia Nacional de Medicina, ex-decano de la Escuela de Medicina de la Universidad Industrial de Santander y notable escritor y psiquiátra doctor Roberto Serpa Flórez, quien presentó su libro sobre medicina y enfermedades tropicales en Colombia en la primera mitad de este siglo que, en forma interesante y amena, desarrolló alrededor de la biografía de su padre, el también Académico de Número profesor Roberto Serpa Novoa.

  18. Caracterización del potencial de abuso del flunitracepam

    OpenAIRE

    Martí de la Llave, Cecilia

    1997-01-01

    Con el presente estudio se pretende caracterizar el potencial de abuso del flunitracepam. La pauta de administración del flunitracepam está ajustada para alcanzar concentraciones máximas plasmáticas similares entre los dos regímenes de administración del fármaco activo, aunque a diferente velocidad; con la dosis única se alcanza la concentración máxima plasmática más rápidamente que con la dosis dividida. Cuando el voluntario recibe el fármaco activo a dosis única toma cinco cápsulas que ...

  19. Del Charco del Agua Amarga (Alcañiz

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    Tomás MAIGI

    2009-10-01

    Full Text Available En agosto de 1947, habiendo llegado a la excelentísima Diputación Provincial de Teruel rumores de recientes deterioros en el friso pintado del abrigo rupestre del "Charco del Agua Amarga", nos fué requerida oficialmente, por dicha Corporación, la presentación de un informe sobre la realidad de los hechos expuestos, así como el planeamiento de las medidas adecuadas para salvaguardar en forma eficaz, en el futuro, las referidas pinturas.

  20. Calidad del servicio de taxis del municipio Maracaibo

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    Joheni A. Urdaneta G.

    2011-05-01

    Full Text Available El presente trabajo tiene como objetivo describir la calidad del servicio de los taxis en el municipio Maracaibo, ya que los mismos forman parte del sistema de transporte urbano de la ciudad, y es un servicio público fundamental para la convivencia de la sociedad; para lograr este objetivo se realizó una adaptación del modelo SERVPERF, diseñando un instrumento tipo cuestionario, con 32 ítems en 6 dimensiones, adecuado a las características propias del servicio de taxi, con la finalidad de confirmar que los ítems de los instrumentos se correspondían con las dimensiones adaptadas se aplicó la técnica de análisis factorial resultando un nuevo instrumento con 24 ítems en 3 dimensiones. Se utilizó la escala de Likert con tres (3 alternativas de respuesta. La investigación es de tipo descriptiva y aplicada, bajo diseño no experimental de tipo transeccional descriptiva y de campo. La población quedó conformada por los usuarios de las líneas de taxis del municipio Maracaibo. Se aplicó muestreo aleatorio por conglomerado. La confiabilidad del instrumento se midió a través del coeficiente alfa de Cronbach resultando de 0,82 lo cual se considera aceptable. Los resultados revelan que la calidad del servicio de taxis del municipio Maracaibo es mediana por lo tanto este servicio es susceptible a mejoras, las cuales son necesarias para elevar la calidad de vida de los marabinos. Este resultado se obtuvo con el instrumento originalmente adaptado de 32 ítems y con el cuestionario resultante del análisis factorial, de 24 ítems; esto confirma lo apropiado de esta técnica, ya que se redujo el número de ítems y de las dimensiones originalmente adaptadas y no se encontraron diferencias significativas en los resultados con ambos instrumentos; de esta manera se puede medir la calidad del servicio de taxis en el municipio Maracaibo a través de las dimensiones: confiabilidad del servicio, socialización y responsabilidad.

  1. DE LA SOCIEDAD DEL CONOCIMIENTO A LA SOCIEDAD DEL RIESGO

    OpenAIRE

    Abdala Cardona, Alejandro

    2013-01-01

    El tiempo en el que vivimos: el siglo XXI, presenta a la vez, retos y exigencias al conjunto global de los habitantes del mundo, puesto que, no solo se nos presenta la actualidad como aquella coyuntura histórica en los que el cambio de los acontecimientos gira en torno al rol central del conocimiento, sino también, en torno al potencial que dicho conocimiento trae tras de sí; es decir, el presente siglo impone al conjunto de personas el rótulo de "sociedad del conocimiento" donde se puede enc...

  2. Historia del desarrollo institucional turístico del Meta

    Directory of Open Access Journals (Sweden)

    Ramón Vergel

    2002-11-01

    el primer plan de desarrollo turístico departamental, se comienza a visualizar diferentes tipologías de turismo que se podían desarrollar como el Ecoturismo y a trabajar en pro de ello. Surge luego el segundo Plan Sectorial del Meta visualizando al turismo como producto. Posteriormente se realiza un Estudio Exploratorio sobre el Potencial Turístico del Meta y la promoción turística del departamento comienza a surgir con la participación en ferias y vitrinas turísticas importantes logrando así fijar un mercado turístico: Bogotá.

  3. Perfil del director hospitalario

    Directory of Open Access Journals (Sweden)

    Gabril Pontón Laverde

    1990-04-01

    Full Text Available RESUMEN El hospital, sin importar su tamaño, es una empresa de servicios con una importante función social que trabaja dentro de las características administrativas y económicas generales, toda vez que actúa dentro de un  SISTEMA ABIERTO con los componentes clásicos de una demanda cíclica de servicios de salud, que requiere de una organización con personas, materiales y equipos que trabajan para dar respuesta a esa carencia y que produce resultados que benefician a la comunidad. Tienen un efecto de retroalimentación (Feed – back con base con las experiencias, expectativas y nuevas demandas de servicios y que trabajan dentro de una comunidad precisa, como parte integrante de un sistema mayor, al cual beneficia y fortalece con sus resultados y del que depende para su supervivencia.

  4. Los presupuestos del Concurso

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    Línea de Investigación “De la Crisis Empresarial

    2006-01-01

    Full Text Available Este escrito es el resultado de uno de los proyectos de investigación adelantados por el Departamento de Derecho Comercial de la Universidad Externado de Colombia. En el se hace una aproximación histórica a los presupuestos para acceder a los trámites concursales en Perú, Argentina y España, analizándolos desde los puntos doctrinal, académico y legal.Así mismo, es parte integrante de un trabajo más amplio que pretende elaborar un documento contentivo del tratamiento que se da a los presupuestos concursales a nivel mundial.En este orden de ideas, nos permitimos presentar un análisis minucioso de la legislación de los citados países iberoamericanos.

  5. cuarto del siglo XX

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    José Antonio Nieto Calmaestra

    2005-01-01

    Full Text Available Los últimos 25 años del siglo XX han supuesto un sustancial cambio en el modelo de crecimiento de la población andaluza. Así, mientras la caída de la fecundidad y la estabilización de las tasas de mortalidad han contribuido a un progresivo retroceso de la vitalidad natural, la masiva emigración de antaño ha dado paso al papel de Andalucía como incipiente foco de inmigración y al creciente protagonismo de movimientos internos de relocalización de la población. Desde el punto de vista territorial estas afirmaciones quedan matizadas por los notables contrastes que se producen entre los distintos ámbitos que conforman la región y que contraponen al medio rural con el urbano, al litoral con el interior o a las grandes ciudades con sus periferias.

  6. del caribe colombiano

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    José Amar A.

    2006-01-01

    Full Text Available La investigación indagó acerca de la construcción de conceptos económicos en una muestra de 50 estudiantes universitarios, residentes en una ciudad multifinanciera de la región Caribe colombiana. Para conocer las conceptualizaciones se aplicó una entrevista en profundidad que permitió indagar sobre la función, valor y circulación del dinero y la emisión y acuñación monetaria. Se encontró que sólo el 24% de los jóvenes universitarios alcanza el nivel de pensamiento económico inferencial, y no hay diferencias significativas de acuerdo con el programa académico al que pertenecen. Los resultados indican que los jóvenes presentan un desfase en cuanto a nivel de pensamiento económico, de acuerdo con el contexto internacional.

  7. Avatares del paradigma conexionista

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    Asier Arias

    2012-02-01

    Full Text Available Hace ahora un año que falleciera David Everett Rumelhart, conexionista pionero y editor junto con James Lloyd McClelland de la llamada “biblia del Procesamiento Distribuido en Paralelo” (PDP. Al mismo tiempo, los dos volúmenes de la referida biblia celebraban su vigésimo quinto cumpleaños. También uno de los padres de la inteligencia artificial, John McCarthy, que bautizara de hecho la disciplina, nos abandonó el pasado mes de octubre a los 84 años. Estas tres efemérides nos sirven de pretexto para un breve recorrido por las derivas y obstáculos a los que se ha enfrentado el llamado paradigma conexionista desde su puesta en escena como alternativa al cognitivismo clásico.

  8. El reordenamiento del mundo

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    Antonio Pasquali

    2015-01-01

    Full Text Available Se publica la propuesta de marco histórico y proyección de futuro de Antonio Pasquiali, en nuestra opinión, es útil referente contextualizado para los ensayos y estudios de caso sobre la formación del comunicador profesional. La evolución reciente de la filosofía, la ciencia y la tecnología llevan a Pasquali a afirmar que la humanidad se encamina lentamente hacia la reformulación global de la moral de la intersubjetividad, y a replantear desde sus cimientos el contrato social que concierne a la comunicación social mediática.

  9. Beneficios del descanso peritoneal

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    Jesús Lucas Martín Espejo

    Full Text Available Introducción: Valorar si el descanso peritoneal, de al menos un día semanal, ha supuesto mejoras en la rehabilitación de los pacientes y el impacto clínico que puede suponer. Nos planteamos además cuantificar el beneficio económico. Material y Método: Se realizó un estudio longitudinal, retrospectivo, descriptivo. De los pacientes atendidos en nuestra unidad desde el 1 de enero de 2014 al 31 de diciembre de 2014, se estudiaron los pacientes que cumplieran todo el año de seguimiento y que no procedieran de otras técnicas de depuración como la hemodiálisis o trasplante renal. La muestra de estudio estuvo compuesta por 40 pacientes, de los que 21 tuvieron prescrito al menos 1 día semanal de descanso peritoneal y 19 pacientes sin descanso. Se recogieron las siguientes variables al inicio del periodo de estudio y a los 12 meses: Variables demográficas, variables relacionadas con el estado de volumen, datos clínicos relacionados con la técnica, se pasó una encuesta de satisfacción a todos los pacientes estudiados, y se recogieron los importes del coste mensual de cada tipo de tratamiento. Resultados: Las diferencias iniciales entre los grupos, eran esperables ya que son los valores en los cuales se ha basado la prescripción del día de descanso. La exposición a la glucosa, al comienzo y al final fue menor en el grupo con descanso. Al año, no se encontró diferencias en los parámetros estudiados. Una encuesta de satisfacción nos reveló a que dedican los pacientes el día de descanso y los que no lo tienen a que lo dedicarían. Conclusiones: El descanso peritoneal no ha supuesto una peor evolución de los parámetros clínicos estudiados al año de seguimiento, cumpliendo las recomendaciones de adecuación de diálisis de las guías clínicas. La exposición a la glucosa, aun sin llegar a ser significativa por la duración del estudio, ha sido menor en el grupo con descanso. El día de descanso ha facilitado a los pacientes

  10. Carta del editor

    Directory of Open Access Journals (Sweden)

    Oscar Mauricio Covarrubias-Moreno

    2014-05-01

    Full Text Available Henos aquí con un nuevo número de RIESED. Después de casi un año de ver la luz, y como lo anticipábamos en la carta del editor que acompañaba al número fundacional, hacer una revista electrónica no ha sido una tarea sencilla. Un año más tarde no podemos sino confirmar esa opinión.Gracias al decidido trabajo de los autores, revisores y miembros del equipo editorial hemos podido hacerlo. El proceso de revisión de los artículos ha merecido un cuidado, dedicación y tiempo especiales, que hicieron necesario demorar unos días la fecha de publicación de este tercer número. Asumimos un compromiso con la calidad y estamos convencidos que esa es la única posibilidad de éxito para una revista científica. El contenido y nivel de los artículos disponibles servirá sin duda como incentivo para que los investigadores deseen publicar sus aportes en RIESED.Agradezco especialmente a la Dra. Gloria Rosique Cedillo, Editora Invitada y Coordinadora de este tercer número, así como al investigador César Nicandro Cruz-Rubio, Editor Asociado, apreciados colegas con quienes he tenido el privilegio de trabajar a lo largo de estos meses, y cuya dedicación y esmero han hecho posible RIESED 3.Por otra parte, derivado de nuestro proyecto editorial informo a ustedes de la creación de la Cátedra RIESED. Educación y Sociedad. Esta Cátedra es una iniciativa que la Universidad del Desarrollo Empresarial y Pedagógico ha impulsado en estrecha colaboración con el Grupo de Investigación en Gobierno Administración y Políticas Públicas (GIGAPP del Instituto Universitario de Investigación Ortega y Gasset (IUIOG, Fundación Ortega – Marañón; así como, con la Academia Internacional de Ciencias Político Administrativas y Estudios de Futuro A.C.La Cátedra está concebida como un espacio de diálogo y reflexión interdisciplinario sobre las diferentes temáticas abordadas en RIESED. En el marco de esta iniciativa académica, se invita a los miembros

  11. Memoria del mal

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    Semprún, Jorge

    2011-06-01

    Full Text Available In May 2003 the twelfth edition of the «Aranguren Conferences» was held. Jorge Semprún gave three keynote speeches titled «Kant and the Maquis’ rucksack», «The radical evil and the Buchenwald latrines» and «Literature and memory of the evil: from Sartre to Paul Ricoeur», all of them grouped under the generic denomination Memory of Evil. The thread running through the three speeches was Semprún’s experience as a political deportee at Buchenwald concentration camp, so close to the Weimar camp of Schiller and Goethe. There, he could experience the radical evil, but also the brotherhood through the antifascist resistance groups who coordinated the various clandestine political groups at the camp. This experience helped him review some of the philosophical readings he had done as a philosphy student at the Sorbonne, as well as those readings he took an interest in following the end of the war. In this way, Semprún went over various authors (Immanuel Kant, André Malraux, Edmund Husserl, Jacques Maritain, Martin Heidegger, Karl Marx, Hannah Arendt, Jean Paul Sartre, Paul Ricoeur or Primo Levi arguing their relationship with the issue of Evil.

    En mayo de 2003 se celebró la duodécima edición de las «Conferencias Aranguren». Jorge Semprún dictó tres conferencias magistrales tituladas «Kant y la mochila del maquis», «El mal radical y las letrinas de Buchenwald» y «Literatura y memoria del mal: de Sartre a Paul Ricoeur», agrupadas todas ellas bajo el título genérico de Memoria del mal. El hilo conductor de las tres intervenciones fue la experiencia de Semprún como deportado político en el campo de concentración de Buchenwald, tan cercano al Weimar de Schiller y Goethe. Allí pudo experimentar el mal radical, pero también la fraternidad, a través de los grupos de resistencia antifascista que coordinaban en el campo los distintos grupos políticos clandestinos. Esta experiencia le sirvió para repasar las lecturas

  12. [Feminismos del siglo XXI

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    M. Xosé Agra

    2013-07-01

    Full Text Available ¿Qué soluciones políticas podemos encontrar para las nuevas formas de subjetividad? ¿Cómo debe la teoría feminista interpretar la voluntad de romper los límites y, al mismo tiempo, la necesidad de normalidad? Los pensadores posmodernos son escépticos respecto de las nociones tradicionales de identidad; los límites que definen al sujeto no sólo construyen sino que también excluyen. Debemos oponernos a las interpretaciones dominantes de normalidad y aceptar otras posibles alternativas a los modelos tradicionales. Necesitamos ir más allá del binario sistema sexo/género y de la orientación sexual y mantener una mentalidad abierta, persiguiendo una filosofía de la libertad.

  13. La materialidad del sonido

    Directory of Open Access Journals (Sweden)

    Esteban Manuel Stepanian Taracido

    2012-04-01

    Full Text Available La investigación sobre los procesos de producción sonora en la crea-ción de obras audiovisuales afectan, en términos generales, a cuestio-nes exclusivamente tecnológicas. Para valorar su rendimiento expresi-vo en la construcción del discurso es imprescindible que, de forma paralela, esta investigación se aborde también desde la perspectiva de la realización audiovisual.Para ello es necesario asumir que los conceptos básicos en los que se fundamenta el desarrollo tecnológico no han de ser necesariamente esenciales en los estudios que se plantean desde puntos de vista creati-vos.En particular es oportuno someter a examen el concepto de fidelidad y reivindicar las posibilidades emotivas, e incluso significantes, de formatos de producción sonora hoy en desuso.

  14. La democracia del futuro

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    Rodrigo Borja

    2015-01-01

    Full Text Available El desarrollo logrado por la informática, la microelectrónica y en general las nuevas tecnologías de la información, hace que del zoon politikon aristotélico se pase al homo digitalis posmoderno, de una "democracia restringida" a una telecracia: en el siglo XXI. El autor vaticina que el voto se hará vía computadores desde casa a través de éstos, los gobernantes podrán tener una relación directa con los gobernados, las consultas populares serán más frecuentes, las implicaciones para los regímenes democráticos serán enormes y es en torno a ellas que reflexiona el autor

  15. Sphagnum growth and ecophysiology during mire succession

    Czech Academy of Sciences Publication Activity Database

    Laine, A. M.; Juurola, E.; Hájek, Tomáš; Tuittila, E. S.

    2011-01-01

    Roč. 167, č. 4 (2011), s. 1115-1125 ISSN 0029-8549 Institutional research plan: CEZ:AV0Z60050516 Keywords : photosynthesis * mire * successional Subject RIV: EF - Botanics Impact factor: 3.412, year: 2011

  16. On the ecology of a Sphagnum Bog

    NARCIS (Netherlands)

    Baas Becking, L.G.M.; Nicolai, E.

    1934-01-01

    For the ecologist systematic units are actors in a play. Whatever their christian- and family-names may be — it is their role, whether master or servant, whether villain or hero — which determines the character of the performance. This performance has, moreover, the property of being both continuous

  17. Valor social del anciano

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    Luna Torres Bertha

    1997-11-01

    Full Text Available

    The old age is been surrounded bymisteries, myths and prejuidices. The concepts and the valoration of the ancient man, have been contradictory. In different places and in many cultural moments, the old man has been taken from the glory to the scorn. The actual world scrolls the ancient in a very fast rhythm; the social changes have generayed conditions of disadvantajes for that group of the population, difficulting even more the process of growing old, that in fact has a lot of limitations. Its important that a lot of professionals from many institutions involved with this important cause, join the work developed by geriatrics and gerontologics;  soin this way we can restore the social values of the ancient, who deserves a peacefull old age in compensation with his participation in the job of building a better society. Only in this way, the fear to grow old will be lost.

    La vejez se ha visto rodeada de tabúes, mitos y prejuicios. Han sido contradictorios los conceptos y la valoración del anciano, quien en lugares y momentos culturales ha estado desde ensalzado hasta despreciado. El mundo actual, desplaza al geronte a ritmo acelerado; los cambios sociales han generado condiciones de marginalidad para ese sector de población, dificultando aun más el proceso de envejecer, que de hecho tiene limitaciones. Es por eso importante que al trabajo que desarrollan geriatras y gerontólogos se sumen otros profesionales y un sinnúmero de entidades; en aras de eliminar prejuicios y rescatar el valor social del anciano, quien por su legado merece un ocaso, que compense su aporte y participación en la construcción de la sociedad, solo así se perderá el miedo a envejecer.

     

  18. Para aprender del pasado

    Directory of Open Access Journals (Sweden)

    Esquivel Valverde, Lidier

    2004-05-01

    Full Text Available Este texto reflexiona sobre la importancia de reconocer el valor que tiene el conocimiento de los eventos del pasado, como fuentes importantes de lecciones aprendidas. Inicia presentando ejemplos de sucesos históricos en Japón y cómo estos han sido utilizados de forma positiva en los procesos de educación en niños y adultos. Posteriormente presenta la realidad de Costa Rica, donde a nivel de la población existe un desconocimiento de hechos históricos sobre el tema, al propiciarse su olvido u ocultamiento. Finalmente, los autores exponen sobre un programa del Área de Prevención de la Comisión Nacional de Prevención de Riesgos y Atención de Emergencias, quienes se han dedicado de distribuir reseñas históricas breves de los principales eventos en el país This text reflects about the importance of recognizing the value of knowing past events as important sources for lessons learned. It starts including examples of historical events in Japan and how they have been used positively in the educational processes for children and adults. Lately, it includes the reality in Costa Rica. The population does not know about historical events on the topic because they have been forgotten or not shared. Finally, the authors refer to a program of the Prevention Area of the National Commission of Risk Prevention and Emergency Response that has dedicated to distribute brief historical reviews about the main events in the country

  19. Discurso del Presidente Entrante

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    Gilberto Rueda Pérez

    1994-09-01

    Full Text Available

    Santafé de Bogotá, D.C., 17 de mayo de 1994

    Señoras y señores:

    Estoy profundamente conmovido y emocionado, al escuchar los elogiosos comentarios de quienes me precedieron en el uso de la palabra, pues, aunque inmerecidos, naturalmente me enorgullecen sobremanera.

    Quiero, antes de iniciar mi discurso, agradecer a la noble Academia de la Lengua, a su presidente doctor Jaime Posada y a los miembros de su Junta Directiva, la generosa hospitalidad en este precioso auditorio que contribuye a dar realce a esta sesión solemne.

    Muchas Gracias.

    Deseo manifestar, que los conceptos que vaya emitir, reflejan mi pensamiento y por tanto, de ellos soy responsable. No pretendo con ellos criticar, ni mucho menos ofender, a personas o instituciones, son más que todo reflexiones, que me llevan a propuestas de trabajo para el futuro y espero que así sean percibidas y analizadas por esta distinguida audiencia.

    El día 3 de enero de 1873, el joven médico Abraham Aparicio, reunió en su residencia, en las primeras horas de la fría noche santafereña, a sus colegas Manuel Plata Azuero, Nicolás Osario, Liborio Zerda, Leoncio Barreta y Evaristo García, con el propósito de crear una sociedad científica, para el estudio y adelanto de las ciencias médicas y naturales, así como para solidarizar al cuerpo médico y darle unidad al ejercicio profesional en el país. Así nació la Sociedad de Medicina y Ciencias Naturales que posteriormente sería elevada a la categoría de Academia Nacional de Medicina, por la Ley 71 de 22 de noviembre de 1890.

    Sin embargo, bien vale la pena rememorar los orígenes aún más remotos, de esta insigne institución.

    El 29 de diciembre de 1816, el Dr. Pablo Fernández de la Reguera, médico cirujano, químico y boticario mayor del ejército expedicionario, inspector de los hospitales, en comunicación dirigida al Sr. Brigadier Don Juan Sámano, Gobernador militar y político de la

  20. Carta del Editor

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    Blasco Fernando Checa Montúfar

    2015-01-01

    Full Text Available En "El laberinto de la ciberred" se habla de los beneficios y problemas que caracteriza el caos existente en la telaraña cibernética. Ahora el cibernauta puede acceder a una inimaginable oferta de información multimedia. Este caos garantiza libertades, pero presenta enormes limitaciones para quienes no tienen acceso a la tecnología, particularmente en países de América Latina, carentes de Políticas de Comunicación que generen condiciones para un uso intensivo, extensivo y democrático de la ciberred. En el tema “La televisión por cable" relacionado con la cultura visual, multimediática, satelital, informática, televisionada, se señala que tiene como soporte a la más antigua nueva tecnología, la televisión por cable. Se trata de uno de los más grandes negocios disputados por los magnates nacionales y transnacionales de la comunicación que atraparon para el año 2000 a más de 20 millones de suscriptores de la televisión pagada. En esta entrega se presentan distintos acercamientos del perfil del ombudsman de prensa, las ventajas y límites de esta institución, su necesaria independencia, trasfondo ético, autonomía y otros aspectos que contribuirán a fortalecer mecanismos adecuados para controlar este "peligroso poder”

  1. Carta del editor

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    Simón Espinosa

    2015-01-01

    Full Text Available La autora relata la historia de las Relaciones Públicas y dice que surgieron y se desarrollaron para legitimar ante el público los intereses económicos y políticos de quienes detentan el poder. Se cuestiona sobre el por qué no aplicar las relaciones públicas, en organizaciones populares, para que mejoren su publicación y orienten sus propósitos de desarrollo. El tema que aborda las Políticas culturales en América Latina acopia un extracto de lo más trascendente de los ensayos del libro editado por Néstor García Canclini. Sobre la telenovela se afirma que esta ha llegado a ser uno de los instrumentos más importantes de la comunicación popular: por ella desfilan las identidades de las más variadas culturas brasileñas. Y en cuanto a la caricatura se relata lo que ocurrió en el Seminario taller " Caricatura y Periodismo", realizado el(9-11 de Nov.- 1987 en el CIESPAL. El estudio sobre el mercado del vídeo se ve dificultado por la imprecisión de los datos obtenidos. Los datos oficiales no siempre se aproximan a la realidad, pues el mercado de vídeo se instauró en América Latina partiendo de una lógica totalmente diversa de los equipos de sonido e imagen.

  2. Los objetivos del desarrollo

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    Currie Lauchlin

    1993-12-01

    Full Text Available To broach the goals of development implies broaching the problem of economic growth in a critical manner. Not only the concept of growth but also the means of achieving it in practice should be questioned. Growth is not an end, it is a means of gaining access to development And development should not be understood as a goal, but as a permanent process of learning tending towards more control over the environment and greater levels of well-being. It is not a matter of increasing GNP linearly; development must occur, sustained growth that, without being a threat to mm or to our natural resources, can lead to the eradication of absolute and relati.ve poverty. The low rates of growth of the developing countries constitute structural problem that can /lot be reso1.ved by resorting to the neo-classical mechanisms of mobility, nor to the Keynesian formulas. These have served as a source of inspiration to the Harrod-lX:m3r·type models of growth which limit themselves to stimulating savings and ending unemployment by concentrating exclusively on the monetary demand. Getting OUt of the vicious circle of low growth implies eradicating poverty with respect into the immediateness of a direct attack on the problem. with respect to the developed counties, growth is starting to became harmful, and, given the prevalence of ostensible consumption and of pecuniary emulation, it is imperative to foment non-economic motivation that will permit the eradication of relative poverty.

    Abordar los objetivos del desarrollo implica abordar de manera crítica el problema del crecimiento econ

  3. Deslumbramientos del mercado

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    Monique Selim

    2006-07-01

    Full Text Available Con eje en los diferentes aspectos que adopta el actual proceso de mundialización de la lógica del mercado y expansión capitalista, aún en países socialistas, el presente artículo plantea la necesidad de una reflexión antropológica susceptible de articular el surgimiento de nuevas formas de dominación y representación simbólicas. Se discute el aparente efecto de unificación intelectual producido por la hegemonía del mercado respecto de hechos sociales heterogéneos dados en la historia reciente de las sociedades contemporáneas. Así, la renovada atracción que ejercen los nuevos escenarios sociales reconfigurados en virtud de las modalidades específicas de encarnación y operación de los procesos globalizantes, llama al estudio antropológico de las coyunturas. La autora despliega una interpretación del socialismo de mercado, conjunción -siempre en tensión- de un monopolio político estatal y una liberalización del mercado económico. En esta perspectiva se reubica el interés de una antropología del presente en relevar localmente, en este caso en Vietnam del Norte, la conformación de un nuevo mercado de demandas simbólicas, donde la reaparición de las prácticas culturales de comunicación con los antepasados expresa la necesidad de reunificación familiar y reconciliación con los muertos en la "larga guerra".Tendo como eixo os aspectos diferentes que adota o processo atual de mundialização da lógica do mercado e de expansão capitalista, até mesmo nos países socialistas, este artigo propoe a necessidade de uma reflexão antropológica capaz de articular o aparecimento de novas formas de dominação e de representação simbólica. Discute-se o efeito de superfície de unificação intelectual causado pela hegemonia do mercado em fatos sociais diversos em sociedades contemporâneas. Assim, a atração renovada de novos fatos sociais pelos modos específicos de incorporação e operação de processos de globaliza

  4. La legitimidad del derecho penal

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    Francisco Bernate-Ochoa

    2010-03-01

    Full Text Available El interrogante sobre la legitimidad del derecho penal se ha convertido en un asunto medular dentro de los estudios contemporáneos sobre la materia, dado que hoy en día se reconoce que a partir de la solución a este interrogante teórico se puede asumir la tarea de construir un sistema. El panorama contemporáneo nos ofrece dos soluciones al respecto: por una parte, se sostiene que la legitimación del derecho penal emana de la Constitución, y se prescinde de una construcción sistémica del delito en aras de la obtención de consecuencias acordes con lo planteado en la Carta Política. Por otra, desde una propuesta -de corte normativista- se entiende que la legitimación del derecho penal debe encontrarse en la sociedad, y a partir del entendimiento de ésta se encuentra la necesidad de aquél, lo cual ejerce una influencia en la construcción del sistema del delito.

  5. Del internacionalismo al nacionalismo: rumbos del conflicto armado en Colombia

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    Mónica Zuleta P.

    2003-10-01

    Full Text Available Este ensayo tiene por propósito sugerir una interpretación del desarrollo del conflicto armado colombiano durante la última década del siglo XX mediante el uso de la concepción de poder de Michel Foucault. Ello con miras a presentar alternativas analíticas frente a la relación entre lo global y lo local donde se consideren algunas de las hipótesis contemporáneas sobre la cuestión del nacionalismo. El ensayo utiliza el término nacionalismo como sustantivo (lo que es en lugar de como adjetivo (lo que debe ser y ordena los conjuntos de acciones que, en torno al proyecto de lo nacional, han sido puestos en práctica por las guerrillas en Colombia.

  6. Gestión del riesgo del cambio (primera parte

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    Juan Pablo Zorrilla

    2007-07-01

    Full Text Available A partir de la desaparición del sistema Bretton-Woods, y la libre flotación del tipo de cambio, el mundo se volvió más susceptible a todo tipo de riesgos. El presente artículo pretende explicar a los gestores financieros o empresarios interesados en el tema de instrumentos financieros derivados, a conocer lo más relevante y necesario acerca del uso de futuros sobre el tipo de cambio, instrumento útil para cubrir riesgos derivados del tipo de cambio para las empresas que se dedican a importar, exportar o para protegerse de un crédito otorgado en moneda extranjera.

  7. Calidad del software: camino hacia una verdadera industria del software

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    Saulo Ernesto Rojas Salamanca

    1999-07-01

    Full Text Available El software es quizá uno de los productos de la ingeniería que más ha evolucionado en muy poco tiempo, pasando desde el software empírico o artesanal hasta llegar al software desarrollado bajo los principios y herramientas de la ingeniería del software. Sin embargo, dentro de estos cambios, las personas encargadas de la elaboración del software se han enfrentado a problemas muy comunes: unos debido a la exigencia cada vez mayor en la capacidad de resultados del software, debido al permanente cambio de condiciones lo que aumenta su complejidad y obsolescencia; y otros, debido a la carencia de herramientas adecuadas y estándares de tipo organizacional encaminados al mejoramiento de los procesos en el desarrollo del software. Hacia la búsqueda de mecanismos de solución de estos últimos problemas se orienta este artículo...

  8. Perspectivas del derecho procesal constitucional

    OpenAIRE

    Hernández-Villarreal, Gabriel-Angel

    2007-01-01

    Este texto recoge las ponencias que participaron en el Foro Internacional de Derecho Procesal Constitucional, que con gran éxito se realizó en el mes de junio de 2005, en las aulas de la Universidad Colegio Mayor de Nuestra Señora del Rosario de Bogotá; razón por la cual contiene el fruto maduro de las investigaciones realizadas por algunos de los más notables exponentes del derecho procesal constitucional en América del Sur. El lector de esta obra se encontrará con riguroso trabajo sobre alg...

  9. Contabilidad del impuesto sobre beneficios

    OpenAIRE

    Luceño Martínez, Haizea

    2017-01-01

    Este Trabajo Fin de Grado pretende dar una explicación al tratamiento contable del Impuesto de Sociedades. Siendo un impuesto que hay que contabilizar, pero que se calcula siguiendo criterios fiscales, lleva a tener que realizar ajustes que tendrán su repercusión contable. El punto de partida no es otra que la norma de registro y valoración 13ª del PGC, que versa sobre cómo hay que proceder a contabilizar el Gasto por Impuesto de Sociedades, que se compone tanto del Gasto por Impuesto Co...

  10. Entrenamiento funcional del core: eje del entrenamiento inteligente

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    Iván Dario Pinzón Ríos

    2015-06-01

    Full Text Available Antecedentes: La evolución del entrenamiento físico busca la optimización de la salud y el bienestar, como piedra angular de todo programa de ejercicio. El Entrenamiento Funcional (EF es recomendable para optimizar el control postural del core, mejorando el balance y la ejecución de actividades de la vida diaria.  Objetivo: Revisar la definición, elementos constitutivos, características e implicaciones del EF del core en el movimiento corporal humano (MCH y la salud desde la perspectiva del fisioterapeuta. Metodología: Se incluyeron artículos en inglés y español de las bases Pubmed, Scielo y Ebsco; adicionalmente se incluyeron fuentes electrónicas e impresas y libros. Resultados: 56 documentos cumplieron los criterios de inclusión. La definición más adoptada de EF fue entrenar con un propósito buscando obtener un efecto positivo en la aptitud física. Las implicaciones del EF en el MCH, se relacionan con la ganancia y mejoría de la estabilidad. La propuesta de EF enfocada a las actividades de la vida diaria incluye fases que permiten adquirir la estabilidad hasta lograr el desarrollo de movimiento que demanden más agilidad. En la planificación del EF se deben estructurar los procesos a ejecutar considerando el criterio de funcionalidad. Para organizar la sesión del EF, el fisioterapeuta cuenta con tres maneras de planificar la sesión: globales, por hemisferios y por grupos musculares. Conclusión: La fundamentación teórica sobre el EF permite al fisioterapeuta comprender y determinar cómo esta modalidad de intervención repercute de manera positiva sobre el desempeño funcional y calidad de vida de los sujetos.

  11. Aspectos Hardware y Software del microprocesador 68000

    OpenAIRE

    Alcaraz Martínez, Raúl

    2009-01-01

    INTRODUCCIÓN AL 68000.ORGANIZACIÓN INTERNA DEL 68000. PROGRAMACIÓN DEL 68000 EN LENGUAJE ENSAMBLADOR. ORGANIZACIÓN EXTERNA DEL 68000. EXCEPCIONES. PROGRAMACIÓN DE LA VÍA 6522. PROGRAMACIÓN DE LA DUART 68681 PARA COMUNICACIÓN SERIE. EVOLUCIÓN DEL 68000

  12. La finalidad del proceso

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    Iván Alfonso Cordero Gutiérrez

    2011-07-01

    Full Text Available Resumen:El tipo de Estado que Colombia asumió desde 1991 (Estado Social de Derecho, implica que el cumplimiento de los fines estatales se comparten con la población, generando de esta forma grados de responsabilidad respecto a las cargas asumidas por ellos y el Estado para la materialización de los objetivos planteados. La satisfacción de las necesidades básicas de la población como unode los fines esenciales del Estado Social de Derecho, no escapa a este esquema, lo que determina la colaboración armónica no sólo entre las entidades y organismos del Estado sino de este, complementado con la población. Una de las necesidades básicas de la población, se refiere a la posibilidad de resolver sus conflictos haciendo uso de los mecanismos que para tal efecto tiene a su disposición, utilizando las formas de Auto tutela, Autocomposición, híbridas y de Heterocomposiciòn, que el Estado autoriza,de acuerdo a los lineamientos propios de cada mecanismo, respecto a las materias que componen los derechos sustanciales que se debaten en la relación conflictiva. Dentro de estos mecanismos de solución de conflictos, la heterocomposiciòn presenta uno llamado el proceso jurisdiccional, en donde un tercero investido de poderes específicos ejerce la jurisdicción y toma la decisión respecto al conflicto, después del agotamiento de etapas sucesivas y preclusivas que garantizan la efectiva participación, ejercicio y defensa de los derechos fundamentales y sustanciales de las partes, generando una mayor garantía de legalidad respecto a la decisión generada por ese tercero investido de plena Jurisdicción (el Juez. Por ser el proceso jurisdiccional el mecanismo más idóneo por su garantismo reglado y tecnificado, debe ser protegido, fortalecido y preferente respecto a los denominados equivalentesjurisdiccionales pues con estos el Estado pretende desplazar la competencia al momento de la resolución de los conflictos, generando un

  13. Hacia una conceptualización del legado del traductor

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    Guzmán María Constanza

    2009-06-01

    Full Text Available Este artículo se propone investigar el aporte de perspectivas traductológicas para el estudio de la figura del traductor y su legado. Se centra en enfoques teóricos contemporáneos, principalmente aquellos basados en perspectivas postestructuralistas, que consideran el papel del sujeto traductor como un aspecto crucial en la traducción y los estudios literarios, y proponen maneras interesantes de abordarlo. A lo largo del artículo se cuestionan nociones como la idea de un original sacralizado, la relación entre autoría y propiedad, el ideal del significado transparente, y la tensión entre la traducción y la escritura del "original". Se presta especial atención a la importancia de ubicar históricamente la práctica del traductor, reconocer su papel como agente visible, y conceptualizar la traducción como una forma de escritura que se desarrolla en medio de complejas interacciones y negociaciones.

  14. HACIA UNA CONCEPTUALIZACIÓN DEL LEGADO DEL TRADUCTOR

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    María Constanza Guzmán

    2009-01-01

    Full Text Available Este artículo se propone investigar el aporte de perspectivas traductológicas para el estudio de la figura del traductor y su legado. Se centra en enfoques teóricos contemporáneos, principalmente aquellos basados en perspectivas postestructuralistas, que consideran el papel del sujeto traductor como un aspecto crucial en la traducción y los estudios literarios, y proponen maneras interesantes de abordarlo. A lo largo del artículo se cuestionan nociones como la idea de un original sacralizado, la relación entre autoría y propiedad, el ideal del significado transparente, y la tensión entre la traducción y la escritura del "original". Se presta especial atención a la importancia de ubicar históricamente la práctica del traductor, reconocer su papel como agente visible, y conceptualizar la traducción como una forma de escritura que se desarrolla en medio de complejas interacciones y negociaciones.

  15. Ensayo del lisado de amebocitos del Limulus (LAL

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    Rolando Perdomo Morales

    2004-04-01

    Full Text Available En los últimos años, los principales organismos reguladores de productos farmacéuticos (Farmacopeas exigen cada vez más en sus monografías la aplicación del método del lisado de amebocitos de Limulus (LAL para la liberación de pirógenos en productos terminados parenterales. El análisis de pirógenos constituye uno de los principales ensayos en el control de calidad de la fabricación de inyectables por su repercusión en la salud humana, puesto que la presencia y administración de los mismos, es capaz de provocar una serie de respuestas fisiológicas, en su mayoría de carácter perjudicial y en casos extremos, la muerte del paciente. Por las razones anteriores, existe un creciente interés en el conocimiento y dominio de estos métodos. El presente trabajo muestra una revisión bibliográfica del método del LAL, se tratan aspectos como su descubrimiento y estandarización, aparición en la industria farmacéutica y razones para su triunfo, y los basamentos de los principales métodos o variaciones comerciales del LAL (gelificación, turbidimétricos y cromogénicos que se describen en las Farmacopeas.

  16. Ensayo del lisado de amebocitos del Limulus (LAL

    Directory of Open Access Journals (Sweden)

    Rolando Perdomo Morales

    Full Text Available En los últimos años, los principales organismos reguladores de productos farmacéuticos (Farmacopeas exigen cada vez más en sus monografías la aplicación del método del lisado de amebocitos de Limulus (LAL para la liberación de pirógenos en productos terminados parenterales. El análisis de pirógenos constituye uno de los principales ensayos en el control de calidad de la fabricación de inyectables por su repercusión en la salud humana, puesto que la presencia y administración de los mismos, es capaz de provocar una serie de respuestas fisiológicas, en su mayoría de carácter perjudicial y en casos extremos, la muerte del paciente. Por las razones anteriores, existe un creciente interés en el conocimiento y dominio de estos métodos. El presente trabajo muestra una revisión bibliográfica del método del LAL, se tratan aspectos como su descubrimiento y estandarización, aparición en la industria farmacéutica y razones para su triunfo, y los basamentos de los principales métodos o variaciones comerciales del LAL (gelificación, turbidimétricos y cromogénicos que se describen en las Farmacopeas.

  17. HACIA UNA CONCEPTUALIZACIÓN DEL LEGADO DEL TRADUCTOR

    Directory of Open Access Journals (Sweden)

    María Constanza Guzmán

    2009-06-01

    Full Text Available Este artículo se propone investigar el aporte de perspectivas traductológicas para el estudio de la figura del traductor y su legado. Se centra en enfoques teóricos contemporáneos, principalmente aquellos basados en perspectivas postestructuralistas, que consideran el papel del sujeto traductor como un aspecto crucial en la traducción y los estudios literarios, y proponen maneras interesantes de abordarlo. A lo largo del artículo se cuestionan nociones como la idea de un original sacralizado, la relación entre autoría y propiedad, el ideal del significado transparente, y la tensión entre la traducción y la escritura del "original". Se presta especial atención a la importancia de ubicar históricamente la práctica del traductor, reconocer su papel como agente visible, y conceptualizar la traducción como una forma de escritura que se desarrolla en medio de complejas interacciones y negociaciones.

  18. Instalaciones del edificio de Costillares

    Directory of Open Access Journals (Sweden)

    Laorden, José

    1999-08-01

    Full Text Available Not available

    Se describen las instalaciones de calefacción y refrigeración, fontanería, gas, central eléctrica, iluminación, teléfonos y aislamiento térmico del edificio construido en Chamartín de la Rosa para sede del instituto Técnico de la Construcción y del Cemento, dando las consideraciones generales que sirvieron para proyectarlas y analizando después para cada una de ellas las bases del proyecto, su ejecución y, finalmente, los primeros resultados de su funcionamiento. De especial interés creemos los comentarios que hacemos sobre algunos errores de proyecto o de ejecución, con lo cual quizá se puedan evitar en otros trabajos.

  19. Virus del Ébola

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    Miguel Lugones Botell

    Full Text Available En la actualidad, el panorama epidemiológico internacional se presenta con enfermedades infecciosas graves como el Ébola. Recientemente han ocurrido brotes en tres países del África Occidental, por lo que la Organización Mundial de la Salud ha insistido acerca del peligro que existe sobre la expansión y gravedad de esta epidemia. Se realizó una revisión bibliográfica del tema con el objetivo de actualizar al médico sobre aspectos esenciales de la fiebre hemorrágica o enfermedad del Ébola. Los índices de letalidad se encuentran entre el 50 y 90 %, por lo que la Organización Mundial de la Salud hace énfasis en la importancia de la prevención mediante la higiene, lo que constituye un aspecto clave.

  20. TEA, Trastorno del Espectro Autista :

    OpenAIRE

    Vegas Martín, Irene

    2015-01-01

    La autora expone los aspectos fundamentales sobre el concepto del TEA para posteriormente mostrarnos un caso práctico y su tratamiento durante unos meses con la finalidad que sea un trabajo de consulta práctico

  1. Comportamiento del riesgo preconcepcional

    Directory of Open Access Journals (Sweden)

    Jesús L Regueira Naranjo

    1998-04-01

    Full Text Available Se realiza un estudio analítico de casos y controles 1 x 1 sobre el comportamiento del riesgo preconcepcional en 35 consultorios, pertenecientes al Policlínico Comunitario Docente "Tula Aguilera", del Municipio Camagüey. El grupo estudio estuvo constituido por las mujeres con riesgo preconcepcional que concibieron un embarazo y fueron captadas en el período desde el 1ro. de enero al 30 de junio de 1994. El grupo control se constituyó con mujeres sin antecedentes de riesgo preconcepcional y que fueron captadas en igual período y la misma área de salud. Los resultados más notables fueron: como riesgo biológico la desnutrición materna III-IV con el 36,76 %, la anemia con el 48,52 %, la sepsis urinaria con el 25 % y la vaginal con 22,79 %. Se demostró la hipótesis de que los niños nacidos de madres con riesgo preconcepcional y obstétrico están expuestos a tener una mayor morbilidad y mortalidad perinatal que los recién nacidos de madres sin riesgo con un embarazo normalAn analytical 1-1 case-control study on the preconceptional risk behaviour in 35 physicians'offices from «Tula Aguilera» community teaching polyclinic located in Camagüey municipality was performed. The group was made up of women with preconceptional risk who got pregnant and were followed-up from January 1st to June 30th, 1994. The control group was formed by women without preconceptional risk history and who were followed-up in the same period of time and in the same health area. The most out-standing results as to biological risks were: maternal malnutrition III-IV, 36.76 %; anemia, 48.52 %; urinary tract infection; 25 % , and vaginal infection, 22.79 %. The hypotesis that infants born from mothers with preconceptional and obstetric risks are exposed to higher perinatal mortality and morbility risks than those from riskless mothers with a normal pregnancy was proved

  2. Caracterización del mercado laboral del sector hotelero del estado Mérida, Venezuela

    OpenAIRE

    Villasmil R., María A.; Andrade, Henry

    2009-01-01

    Esta investigación trata sobre modelos que permiten caracterizar Mercados Laborales Locales (MLL), ya que en Venezuela el manejo de los mismos es casi inexistente. En este sentido, se plantea como objetivo caracterizar al mercado laboral del sector hotelero del estado Mérida-Venezuela en función del conocimiento de las particularidades económicas, institucionales, políticas, sociales, educativas y culturales de la zona así como las condiciones que se tengan en materia de empleo, oferta de for...

  3. EFECTO DEL SILICIO Y PLAGUICIDAS EN LA FERTILIDAD DEL SUELO Y RENDIMIENTO DEL ARROZ

    OpenAIRE

    Parm\\u00E9nides Furcal-Beriguete; Alejandra Herrera-Barrantes

    2013-01-01

    El objetivo de este trabajo fue evaluar el efecto del silicio en la fertilidad del suelo, la incidencia de enfermedades y plagas insectiles, el rendimiento y la calidad de granos del cultivo de arroz. El estudio se realizó en La Vega, Florencia, San Carlos, Costa Rica entre mayo y octubre en los años 2010 y 2011, en el mismo lote con la variedad CR 4477. Se establecieron cinco tratamientos: silicio al suelo, silicio al suelo más plaguicidas (alternativas químicas), silicio foliar, silicio fol...

  4. Conservacion de truchas del Pacifico

    Science.gov (United States)

    Brooke E. Penaluna

    2016-01-01

    La historia de las truchas del Pacífico, pertenecientes al género Oncorhynchus, es una historia muy interesante que se basa en la persistencia y diversificación de sus especies debido, en gran parte, al dinamismo propio que existe en su medio ambiente. Desde el oeste de Norteamérica, extendiéndose hasta el este de Asia, las truchas del Pacífico han experimentado la...

  5. Carta del editor

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    Juan Braun

    2015-01-01

    Full Text Available Son temas de interés de esta entrega Mujeres, comunicación y desarrollo, en el que se arenga a todas a no solo luchar por el género sino por una sociedad más libre y más justa, de la mano de los hombres. Abre un amplio espectro para exponer la situación de la mujer; Mujer e Iglesia,Prensa, Mujer y revolución, Mujeres comunicadoras, mujer líder comunitaria, etc. Periodismo deportivo, que nunca se incluyó en la revista, hoy gracias a la tecnología, la televisión y la publicidad es el género de mayor crecimiento en el mundo. El tema abarca: Génesis del deporte, Fútbol México - 86. Maradona, Deporte y negocio, Análisis de una Olimpiada, Prensa Olimpiadas y política, Juegos Panamericanos, Escuelas de Periodismo deportivo, Cadenas deportivas en televisión. Se incluye entrevistas a cuatro Mujeres Comunicadoras.

  6. Los Anhelos Del Agro

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    Chaparro G. A.

    1942-08-01

    Full Text Available Hablemos hoy del campesino y de su desventura, y hagámoslo, perfectamente libres de toda insana y falaz intención demagógica. Démosle el frente con resolución a esa obscura costumbre de halagar las pasiones de las gentes y explotar con fines proclives las profundas esperanzas y los honrados anhelos de los campesinos, y digamos que en Colombia, y en muchos países de América, se ha abusado impunemente de esa masa resignada que sustenta las economías de estos países, y se ha desconocido el meollo verdadero de sus problemas fundamentales, sin que las fórmulas prácticas de resolvemos íntegramente hayan aparecido, limitándose la acción a meras iniciativas aisladas e inconexas a veces contradictorias, cuyos resultados quedan perdidos en medio de la magnitud total de las situaciones.

  7. A Favor del Plagio

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    Manuel Arranz

    2007-11-01

    Full Text Available Yo no tengo nada contra el plagio. Ustedes, como lectores, seguramente tampoco. Bueno, tal vez prejuicios. Es lógico que los tengan con tanto artículo condenándolo. Hasta ahora, que yo sepa, nadie ha escrito para defenderlo. Los que sí tienen algo, parece ser, son los autores. Una minoría al fin y al cabo. Ya sé que hay que respetar el derecho de las minorías, pero el asunto del plagio, como tantos otros, deberíamos examinarlo con más detalle, y preguntarnos, por ejemplo, ¿por qué se molestan tanto los autores cuando les plagian? ¿En nombre de qué?, sería también una buena pregunta. No me irán a decir a estas alturas que en nombre de la comunidad científica. A fin de cuentas el plagio beneficia la difusión de la ciencia. Los autores se molestan en nombre propio. Naturalmente tienen su derecho, no se lo vamos a discutir, pero, ¿no demuestra eso cierto narcisismo impropio de un científico? ¿La ciencia no es de todos?, como suelen decir en otras ocasiones.

  8. La liberazione del tempo

    CERN Document Server

    Selleri, Franco

    2003-01-01

    Negli ultimi dieci anni ho lavorato alla descrizione dei fenomeni naturali da parte di osservatori in movimento. E' un problema che molti credono risolto una volta per tutte dalle trasformazioni di Lorentz della teoria della relatività speciale (TRS nel seguito), ma che in realtà era rimasto aperto per una serie di ragioni che esporrò. Sento di dover dire che ho trovato risultati molto importanti, anche se il giudizio finale sul loro valore non può certo essere il mio. Infatti la conclusione di questa ricerca è duplice: una spiegazione dei dati empirici migliore di quella relativistica, e l'eliminazione di quegli aspetti della TRS che fanno a pugni con il buon senso; il tutto grazie alla liberazione del tempo dall'asservimento alle coordinate spaziali cui era stato costretto nello spazio a quattro dimensioni di Minkowski. La faccenda è raccontata con dovizia di particolari in un libro recente [FS]. Nel presente articolo espongo gli aspetti salienti della ricerca lasciando da parte quelli matematici.

  9. del establecimiento permanente

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    V. Ma. Antonieta Martin Granados

    2002-01-01

    Full Text Available A pesar de que en México se han realizado adiciones a la legislación en materia civil y mercantil relacionadas con el uso de medios electrónicos como instrumentos para realizar actos jurídicos, éstas resultan insuficientes, pues nada se ha hecho en materia procesal, penal y laboral, entre otras. En este trabajo se presentan, en materia fiscal, algunas consideraciones acerca del concepto de establecimiento permanente tanto en la legislación mexicana como en el Convenio Modelo (CM de la Organización para la Cooperación y Desarrollo Económico (OCDE y se argumenta que a pesar de que la definición de la legislación mexicana es mucho más amplia que la que se encuentra en el mencionado convenio, el comercio electrónico presenta algunos retos para determinar el lugar en donde residen las partes involucradas, el lugar en donde se celebran las operaciones y se pagan o cobran, sobre todo tratándose de servicios o adquisición de bienes intangibles. Por último, se señala que en materia fiscal es necesario que las autoridades mexicanas permitan el uso de la factura electrónica

  10. del siglo XX

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    Alejandro González Morales

    2006-01-01

    Full Text Available En este trabajo analizamos las diferentes etapas por las que ha pasado el desarrollo turístico de la isla de Lanzarote. Se distinguen tres periodos de características diferenciadas. El primero, antes de los años setenta, supone el desarrollo de una incipiente industria turística, donde predominan el capital belga y francés; el segundo es un periodo que abarca desde 1973 hasta 1983, en estos 10 años la isla experimenta un cambio sustancial, el capital alemán se vuelve hegemónico y se desarrolla con fuerza el denominado turismo de masas, sobre todo en el municipio de Tías (Puerto del Carmen; por último a partir de principios de los ochenta nos encontramos con una etapa de similares características que la anterior hasta 1995, con un gran desarrollo de Yaiza y Teguise, a partir de esta fecha y hasta la actualidad se introducen los valores de sostenibilidad, aunque sin demasiado éxito, pues se sigue construyendo mucho y no de precisamente alta calidad.

  11. Carta del Editor

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    Blasco Fernando Checa Montúfar

    2015-01-01

    Full Text Available En la sección Sociedad, mujer y comunicación, analiza, expone propuestas, experiencias novedosas y aportes teóricos en torno a la problemática de la discriminación de la mujer en el periodismo, pues pese a los avances de la causa femenina todavía perduran estereotipos y discrímenes en la organización y contenidos mediáticos. En Erotismo, Pornografía y Medios se establecen las diferencias entre los dos primeros términos. Señala que los medios son el escenario privilegiado de estas expresiones sexuales. Incluyen dos experiencias, una sobre radio erótica que busca recrear "el prohibido sonido del placer" y la otra una revista brasileña "El tercer sexo", caso inédito, que rompiendo tabúes, aparece para satisfacer los requerimientos informativos de los homosexuales de Brasil. Completan esta entrega con temas como: El mercado audiovisual latinoamericano; La información exterior en América Latina; Tumbas de papel, sobre los desaparecidos en la dictadura argentina; la ciencia como cultura; Variedades de la luz y el abandono.

  12. Calculo del valor en riesgo del futuro de energia e internacionalizacion del sector energetico en Colombia

    OpenAIRE

    Esquivel Fonseca, Leidy Gioanna

    2013-01-01

    El presente trabajo de grado busca definir cuál es el mejor método para determinar el valor en riesgo del contrato de futuro de energía eléctrica que se transa en Colombia, para cumplir con este objetivo se toma como referencia el marco histórico del VaR y de los futuros seguido de las características de la fijación de precios, la estructura del contrato, que políticas y métodos hay para cubrirse del riesgo y como se realiza en otros países, realizando algunos cálculos de los modelos más trad...

  13. Funciones del estilo personal del terapeuta en profesionales del campo de las adicciones

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    Leandro Casari

    2017-01-01

    Full Text Available Objetivo. Comparar el estilo personal del terapeuta entre dos grupos de profesionales, uno dedicado a la atención de pacientes drogodependientes (grupo adicciones y otro a la atención clínica en general (grupo clínico. Método. La muestra estuvo formada por 100 psicoterapeutas que trabajan en instituciones públicas y privadas de tres provincias del interior de Argentina, pareados por las variables socioprofesionales (sexo, edad, años de experiencia profesional, enfoque teórico, grupo etario de trabajo, tipo de abordaje predominante, duración del tratamiento y grado de especialización. El instrumento empleado fue el Cuestionario de Estilo Personal del Terapeuta. Resultados. Para el análisis de datos se emplearon pruebas de comparación de medias y se analizó su tamaño del efecto. Se obtuvieron diferencias signifi cativas en la función expresiva: grupo clínico (M = 40.36 y grupo adicciones (M = 29.86; así como también en la función instruccional: grupo clínico (M = 28.01 y grupo adicciones (M = 32.67. Esto indica una mayor distancia emocional y un incremento en la rigidez del encuadre terapéutico en los terapeutas de pacientes adictos. Conclusión. Se discuten estos resultados en función de postulados previos que señalan la complejidad del vínculo terapéutico y el énfasis en las características del encuadre terapéutico, tal como la puesta de límites.

  14. Comunidades vegetales de las transiciones terrestre-acuáticas del páramo de Chingaza, Colombia

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    Udo Schmidt-Mumm

    2012-03-01

    Full Text Available La vegetación acuática y semiacuática de los páramos andinos ha sido estudiada generalmente bajo un enfoque fitosociológico tradicional, el cual se basa en muestreos de áreas homogéneas y excluye los fenómenos de borde o transicionales. En el presente estudio se analizó la vegetación acuática y semiacuática del Parque Nacional Natural Chingaza a lo largo de diferentes gradientes hídricos. Asimismo se registran un total de 89 especies en 30 transectos; mediante clasificación numérica y el análisis de especies indicadoras se caracterizan las siguientes 18 comunidades: 1 Calamagrostis effusa, 2 Sphagnum cuspidatum, 3 Cyperus rufus, 4 Eleocharis stenocarpa, 5 Carex acutata, 6 Poa annua, 7 Valeriana sp., 8 Ranunculus flagelliformis, 9 Carex bonplandii, 10 Festuca andicola, 11 Muhlenbergia fastigiata, 12 Elatine paramoana, 13 Isoëtes palmeri, 14 Crassula venezuelensis, 15 Lilaeopsis macloviana, 16 Callitriche nubigena, 17 Potamogeton paramoanus y 18 Potamogeton illinoensis. La ordenación de las comunidades indica la presencia de tres gradientes terrestre-acuáticos diferentes, los cuales se relacionan con las formas de vida de las especies que caracterizan las comunidades. Además se considera que gran parte de la heterogeneidad presentada por la vegetación es el resultado de las alteraciones ambientales generadas por diversas actividades humanas (quemas, ganadería, extracción de material para la construcción de carreteras y la represa.Plant communities in the terrestrial-aquatic transition zone in the paramo of Chingaza, Colombia. High Andean paramo ecosystems are an important water resource for many towns, and major cities in this region. The aquatic and wetland vegetation of different paramo lakes, pond, swamps and bogs was studied according to the classical phytosociological approach, which is based on homogenous stands, but excludes any border phenomena or transitional zone. The present research aimed at determining the

  15. Estrategias del Teatro del Oprimido para la formación permanente del profesorado

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    Tomás Motos-Teruel

    2012-01-01

    Full Text Available Este artículo relata una experiencia y su valoración de formación permanente del profesorado basada en el aprendizaje vivencial utilizando como estrategia metodológica el Teatro del Oprimido (TO para estimular y favorecer la reflexión sobre la práctica educativa. Sus objetivos básicos fueron dar a conocer la formulación teórica y la metodología del TO y hacer la transferencia de las estrategias metodológicas vivenciadas a la práctica docente. El estudio se ha planteado desde una óptica cualitativa con el estudio de caso único. Y como resultados más destacables hay que reseñar el interés y la percepción de la utilidad personal y profesional del TO como instrumento de reflexión sobre la acción y generador de clima positivo. El Teatro del Oprimido es una formulación teórica y un método estético cuya teoría y praxis están inspiradas en la Pedagogía del Oprimido de Paulo Freire, utiliza las técnicas dramáticas como un instrumento eficaz para la comprensión y la búsqueda de alternativas a problemas sociales, interpersonales e individuales.

  16. Franco Modigliani e la teoria del ciclo vitale del consumo

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    Angus Deaton

    2005-06-01

    Full Text Available Nei primi anni ’50, Franco Modigliani e il suo studente Richard Brumberg elaborarono una teoria della spesa fondata sull’idea che gli individui effettuano scelte intelligenti su quanto desiderano spendere a ogni età, con il solo limite delle risorse disponibili nel corso della loro vita. Attraverso l’accumulo e il decumulo delle attività, chi lavora può provvedere alla propriapensione e, più in generale, può adattare i propri modelli di consumo alle esigenze che sipresentano alle diverse età, indipendentemente dal reddito disponibile in ogni momento della suavita. Questa semplice teoria conduce a previsioni rilevanti e non scontate per l’economia nel suo complesso, ad esempio che il risparmio nazionale dipende dal tasso di crescita del reddito nazionale e non dal suo livello, e che esiste una semplice relazione tra il livello della ricchezza nelsistema economico e la lunghezza del periodo trascorso in pensione. Tali previsioni, non verificabili negli anni ’50, hanno trovato considerevole sostegno empirico in successivi lavori di Modigliani e di altri ricercatori. Sebbene nel corso degli anni la teoria del consumo abbia subitonumerosi attacchi, i più recenti dei quali mossi da una coalizione di psicologi ed economisti,l’ipotesi del ciclo vitale rimane una parte essenziale del pensiero degli economisti.

  17. Disgerminoma del ovario (D

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    Jorge Amorocho

    1949-05-01

    Full Text Available Hospital de San Juan de Dios. Pabellón Quirúrgico. Clínica Ginecológica. Servicio del Profesor Aparicio. Historia Clínica número 49-24. G. C. Edad: 36 años. Natural de Susa. Ingresó al Servicio el 28 de febrero de 1949. Antecedentes a Familiares: Sin importancia. b Patológicos: Sarampión, viruela y tos ferina en la infancia. c Quirúrgicos; No. d Traumáticos; Golpe fuerte en la rodilla izquierda hace 4 años, sin fractura. e Tóxicos: Sin importancia. f Obstétricos; Casada desde hace 12 años, vive con el marido y no ha tenido embarazos. Frigidez sexual. g Ginecológicos; Amenorrea primitiva. Su primera regla la tuvo a los 23 años de edad, ' mediante tratamiento especial, a base de estrógenos (distil-estil-gestrol de 0.005 gm. Posteriormente cada 60 días experimentaba malestar general y mediante la ingestión de 2 comprimidos diarios, durante 10 días, de dietil-estil-bestrol de 5 mg. le aparecía su regla que era amenálgica, hipomenorreica y de 4 días de duración. En la fase premenstrual, esto es, mis ntras estaba tornando los comprimidos, le molestaba un flujo blancuzco, claro e inodoro que le almidonaba la ropa; dicho flujo desaparecía tan pronto como venía la menstruación, lo mismo que los síntomas de malestar general.

  18. EFECTO DEL SILICIO Y PLAGUICIDAS EN LA FERTILIDAD DEL SUELO Y RENDIMIENTO DEL ARROZ

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    Parm\\u00E9nides Furcal-Beriguete

    2013-01-01

    Full Text Available El objetivo de este trabajo fue evaluar el efecto del silicio en la fertilidad del suelo, la incidencia de enfermedades y plagas insectiles, el rendimiento y la calidad de granos del cultivo de arroz. El estudio se realizó en La Vega, Florencia, San Carlos, Costa Rica entre mayo y octubre en los años 2010 y 2011, en el mismo lote con la variedad CR 4477. Se establecieron cinco tratamientos: silicio al suelo, silicio al suelo más plaguicidas (alternativas químicas, silicio foliar, silicio foliar más plaguicidas y testigo comercial. Como fuente se utilizaron si- licio en polvo al 70% de SiO2, aplicado quince días antes de siembra en dosis de 100 kg SiO2/ha, y líquido concentrado 40% SiO2 y 36% MgO, aplicado al follaje en dosis de 4 l/ha a los 17 y 30 días después de la siembra. El suelo del orden inceptisol de formación aluvial, al inicio del experimento tenía pH 4,9, valores de P y Si disponibles de 29 ppm y 44,7 ppm, respectivamente, acidez intercambiable 1,2 cmol(+/l y suma de bases 19,11 cmol(+/l. No hubo diferencia estadística significativa del silicio en la fertilidad del suelo, la incidencia de plagas y enfermedades, y en la calidad molinera; sin embargo, la combinación del silicio aplicado al suelo y el uso de plaguicidas incrementaron el contenido de zinc y cobre en el suelo, y del zinc y magnesio en las hojas de arroz, pero este efecto no se tradujo en rendimiento y calidad de granos. La aplicación de plaguicidas influyó positivamente en el peso y rendimiento del arroz en granza (p≤0,05.

  19. Epidemiologia del parasitismo intestinal infantil en el Valle del Guadalquivir

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    Pérez Armengol Cristina

    1997-01-01

    Full Text Available FUNDAMENTO: Las parasitosis intestinales en los niños constituyen un problema de salud pública que debe ser valorado periódicamente en cada región. En este trabajo se aborda, por primera vez en la región natural del Valle del Guadalquivir, un estudio amplio sobre la prevalencia del parasitismo intestinal en la población infantil de la zona. MÉTODOS: Durante el período 1994-1996, mediante análisis coprológico y método de Graham, se ha estudiado a 1.917 niños y niñas asintomáticos, con edades comprendidas entre seis y diez años, residentes en veinte localidades del Valle del Guadalquivir. RESULTADOS: El índice global de parasitación ha sido del 27,12 %. Las especies parásitas detectadas, así como sus prevalencias fueron: Enterobius vermicularis (20,44%, Giardia lamblia (5,05%, Entamoeba coli (2,45%, Endolimax nana (1,61%, Entamoeba histolytica (0,31%, Entamoeba hartmanni (0,05%, Iodamoeba bütschlii (0,05%. CONCLUSIONES: La prevalencia global encontrada es similar a la de otras regiones españolas, aunque quizás pueda considerarse algo más favorable. No se detectan geohelmintos, debido posiblemente a la mejora de la infraestructura higiénico-sanitaria y a los efectos de la prolongada sequía en la zona. La giardiasis, a diferencia de las restantes protozoosis, mantiene una prevalencia relativamente alta.

  20. El valor del consejo en el Libro del caballero Zifar

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    Patricia ROCHWERT-ZUILI

    2011-11-01

    Full Text Available El propósito de este artículo es mostrar el valor que cobra en el Libro del caballero Zifar la definición del consejo como elemento fundamental del molinismo. El análisis permite distinguir no solo la afirmación de una palabra linajística ejemplar sino también la importancia del consejo del verdadero amigo, y en particular, el de la mujer o del caballero. A través de la valoración de la prueba que le tiene que imponer el rey al consejero se vislumbra además la imagen de este consejo privado que se impuso bajo el reinado de Alfonso XI y cuyo papel no fue sino confortar el poder de la realeza.Le propos de cet article est de montrer l’importance que revêt dans le Livre du chevalier Zifar la définition du conseil comme trait essentiel du molinisme. L’analyse permet non seulement de mettre en évidence l’affirmation d’une parole lignagère exemplaire mais aussi de distinguer le conseil de l’ami véritable, en particulier celui de la femme ou du chevalier. À travers la valorisation de l’épreuve que le roi se doit d’imposer au conseiller, on entrevoit en outre l’image du conseil privé qui s’imposa sous le règne d’Alphonse XI et dont le rôle fut de conforter le pouvoir de la royauté.