Sample records for uraniferous bog deposit

  1. The Robinson and Weatherly uraniferous pyrobitumen deposits near Placerville, San Miguel County, Colorado

    USGS Publications Warehouse

    Wilmarth, V.R.; Vickers, R.C.

    1952-01-01

    Uranium deposits that contain uraniferous pyrobitumen of possible hydrothermal origin occur at the Weatherly and Robinson properties near Placerville, San Miguel County, Colo. These deposits were mined for copper, silver, and gold more than 50 years ago and were developed for uranium in 1950.

  2. Bogs

    NSDL National Science Digital Library

    Dragonfly TV

    Did you know that some things are preserved in bogs rather than decomposed? In this episode Amy and Maya take advantage of a bog near them to see whether or not certain materials changed after being buried in the bog for two to four weeks. Check out what they learned and find cool experiments that you can try at home!

  3. The Robinson and Weatherly uraniferous pyrobitumen deposits near Placerville, San Miguel County, Colorado

    USGS Publications Warehouse

    Wilmarth, V.R.; Vickers, R.C.

    1953-01-01

    Uranium deposits that contain uraniferous pyrobitumen of possible hydrothermal origin occur at the Weatherly and Robinson properties near Placerville, San Miguel County, Colo. These deposits were mined for copper, silver, and gold more than 50 years ago and were developed for uranium in 1950. The Robinson property, half a mile east of Placerville, consists of the White Spar, New Discovery Lode, and Barbara Jo claims. The rocks in this area are nearly horizontal sandstones, shales, limestones, and conglomerates of the Cutler formation of Permian age and the Dolores formation of Triassic and Jurassic (?) age. These rocks have been faulted extensively and intruded by a Tertiary (?) andesite porphyry dike. Uranium-bearing pyrobitumen associated with tennantite, tetrahedrite, galena, sphalerite, chalcopyrite, bornite, azurite, malachite, calcite, barite, and quartz occurs in a lenticular body as much as 40 feet long and 6 feet wide along a northwest-trending, steeply dipping normal fault. The uranium content of eleven samples from the uranium deposit ranges from 0.001 to 0.045 percent uranium and averages about 0.02 percent uranium. The Weatherly property, about a mile northwest of Placerville, consists of the Black King claims nos. 1, 4, and 5. The rocks in this area include the complexly faulted Cutler formation of Permian age and the Dolores formation of Triassic and Jurassic (?) age. Uranium-bearing pyrobitumen arid uranophane occur, along a northwest-trending, steeply dipping normal fault and in the sedimentary rocks on the hanging wall of the fault. Lens-shaped deposits in the fault zone are as much as 6 feet long and 2 feet wide and contain as much as 9 percent uranium; whereas channel samples across the fault zone contain from 0.001 to 0.014 percent uranium. Tetrahedrite, chalcopyrite, galena, sphalerite, fuchsite, malachite, azurite, erythrite, bornite, and molybdite in a gangue of pyrite, calcite, barite, and quartz are associated with the uraniferous material. In the sedimentary rocks on the hanging wall, uranium-bearing pyrobitumen occurs in replacement lenses as much as,8 inches wide and 6 feet long, and in nodules as much as 6 inches in diameter for approximately 100 feet away from the fault. Pyrite and calcite are closely associated with the uraniferous material in the sedimentary rocks. Samples from the replacement bodies contain from 0. 007 to 1.4 percent uranium.

  4. Peat bog records of atmospheric mercury deposition

    Microsoft Academic Search

    Poul Pheiffer Madsen

    1981-01-01

    There have recently been many investigations using atmospheric mercury deposition as an indicator of the impact of industrial development, especially in the Northern Hemisphere. Thus, mosses have been used as indicators of airborne mercury pollution1,2, both wet and dry deposition have been analysed for mercury3,4, and mercury concentrations in 18O\\/16O dated ice core samples from the Greenland Ice Sheet have

  5. The biogeochemistry of an ombrotrophic bog: Evaluation of use as an archive of atmospheric mercury deposition

    SciTech Connect

    Benoit, J.M.; Fitzgerald, W.F. [Univ. of Connecticut, Groton, CT (United States). Dept. of Marine Sciences] [Univ. of Connecticut, Groton, CT (United States). Dept. of Marine Sciences; Damman, A.W.H. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Ecology and Evolutionary Biology] [Univ. of Connecticut, Storrs, CT (United States). Dept. of Ecology and Evolutionary Biology

    1998-08-01

    The utility of ombrotrophic bogs as archives of atmospheric mercury deposition was assessed with an investigation in Arlberg Bog, Minnesota, US. Since the use of ombrotrophic bogs as archives depends on the immobility of deposited trace metals, the authors examined the postdepositional transport processes revealed by the solid-phase distributions of mercury and ancillary metals in this bog. They modeled metal speciation in bog pore-waters as a function of pe in order to understand metal behavior in ombrotrophic peat. Specifically, they considered the effect of water movement and resultant shifts in redox potential gradients on metal retention. The results indicate that Hg and Pb are immobile in ombrotrophic peat, so their distribution can be used to determine temporal changes in deposition. To substantiate the deposition estimates determined in this study, they emphasized the importance of confirming the validity of the dating scheme, assessing the degree of horizontal homogeneity in the accumulation record, and providing evidence for retention of Hg based on geochemical modeling. As recorded in Arlberg Bog, historic atmospheric Hg deposition increased gradually after the mid-1800s, peaked between 1950 and 1960, and may have declined thereafter. Preindustrial deposition was about 4 {micro}g/m{sup 2} year and recent deposition about 19 {micro}g/m{sup 2} year. The results of this study indicate that deposition at Arlberg Bog has been influenced by a regional and/or local-scale source.

  6. Effects of elevated carbon dioxide and increased nitrogen deposition on bog vegetation in the Netherlands

    Microsoft Academic Search

    Monique M. P. D. Heijmans; Frank Berendse; Wim J. Arp; Ab K. Masselink; Herman Klees; Willem De Visser; Nico Van Breemen

    2001-01-01

    1 We studied the effects of elevated atmospheric CO2 and increased N deposition on the plant species composition of a Sphagnum-dominated bog ecosystem in the Netherlands. Large peat monoliths (surface area 1 m2, depth 0.6 m) with intact bog vegetation were kept outdoors in large containers and were exposed to elevated CO2 or increased N deposition for three growing seasons.

  7. Quantifying Dry NH 3 Deposition to an Ombrotrophic Bog from an Automated NH 3 Field Release System

    Microsoft Academic Search

    Ian D. Leith; Lucy J. Sheppard; David Fowler; J. Neil Cape; Matt Jones; Alan Crossley; Ken J. Hargreaves; Y. Sim Tang; Mark Theobald; Mark R. Sutton

    2004-01-01

    Providing an accurate estimate of the dry component of N deposition to low N background, semi-natural habitats, such as bogs and upland moors dominated by Calluna vulgaris is difficult, but essential to relate nitrogen deposition to effects in these communities. To quantify the effects of NH3 inputs to moorland vegetation growing on a bog at a field scale, a field

  8. An assessment of isotopic equilibrium in goethites from a bog iron deposit and a lateritic regolith

    Microsoft Academic Search

    Crayton J. Yapp

    1997-01-01

    Hydrogen and oxygen isotope ratios have been measured in goethites from a lateritic regolith in the eastern Amazon Basin of Brazil and a young bog iron deposit in New Jersey, USA. The presence of exchangeable hydrogen and admixed minerals required the use of material-balance calculations to determine relevant ?D and ?18O values. For the Brazilian goethite, ?D is ?121‰ and

  9. Expansion of invasive species on ombrotrophic bogs: desiccation or high N deposition?

    Microsoft Academic Search

    HILDE B. M. TOMASSEN; ALFONS J. P. SMOLDERS; JUUL LIMPENS; LEON P. M. LAMERS; JAN G. M. ROELOFS

    2004-01-01

    1. In many ombrotrophic bog areas the invasion of grass (e.g. Molinia caerulea) and tree (e.g. Betula pubescens) species has become a major problem. We investigated whether the invasion of such species is due to high atmospheric nitrogen (N) deposition by conducting a fertilization experiment. 2. The effects of experimentally increased N input on Molinia, Betula and Eriophorum vaginatum were

  10. Controls on suppression of methane flux from a peat bog subjected to simulated acid rain sulfate deposition

    Microsoft Academic Search

    Vincent Gauci; Nancy Dise; David Fowler

    2002-01-01

    The effect of acid rain SO42- deposition on peatland CH4 emissions was examined by manipulating SO42- inputs to a pristine raised peat bog in northern Scotland. Weekly pulses of dissolved Na2SO4 were applied to the bog over two years in doses of 25, 50, and 100 kg S ha-1 yr-1, reflecting the range of pollutant S deposition loads experienced in

  11. An automated wet deposition system to compare the effects of reduced and oxidised N on ombrotrophic bog species: Practical considerations

    Microsoft Academic Search

    L. J. Sheppard; A. Crossley; I. D. Leith; K. J. Hargreaves; J. A. Carfrae; N. van Dijk; J. N. Cape; D. Sleep; D. Fowler; J. A. Raven

    2004-01-01

    Critical N loads for ombrotrophic bogs, which often contain rare and N-sensitive plants (especially those in lower plant groups: lichens, mosses and liverworts), are based on very few experimental data from measured, low background N deposition areas. Additionally the relative effects of reduced versus oxidised N are largely unknown. This paper describes an automated field exposure system (30 km S.

  12. Small scale controls of greenhouse gas release under elevated N deposition rates in a restoring peat bog in NW Germany

    NASA Astrophysics Data System (ADS)

    Glatzel, S.; Forbrich, I.; Krüger, C.; Lemke, S.; Gerold, G.

    2008-06-01

    In Central Europe, most bogs have a history of drainage and many of them are currently being restored. Success of restoration as well as greenhouse gas exchange of these bogs is influenced by environmental stress factors as drought and atmospheric nitrogen deposition. We determined the methane and nitrous oxide exchange of sites in the strongly decomposed center and less decomposed edge of the Pietzmoor bog in NW Germany in 2004. Also, we examined the methane and nitrous oxide exchange of mesocosms from the center and edge before, during, and following a drainage experiment as well as carbon dioxide release from disturbed unfertilized and nitrogen fertilized surface peat. In the field, methane fluxes ranged from 0 to 3.8 mg m-2 h-1 and were highest from hollows. Field nitrous oxide fluxes ranged from 0 to 574 ?g m-2 h-1 and were elevated at the edge. A large Eriophorum vaginatum tussock showed decreasing nitrous oxide release as the season progressed. Drainage of mesocosms decreased methane release to 0, even during rewetting. There was a tendency for a decrease of nitrous oxide release during drainage and for an increase in nitrous oxide release during rewetting. Nitrogen fertilization did not increase decomposition of surface peat. Our examinations suggest a competition between vascular vegetation and denitrifiers for excess nitrogen. We also provide evidence that the von Post humification index can be used to explain nitrous oxide release from bogs, if the role of vascular vegetation is also considered. An assessment of the greenhouse gas release from nitrogen saturated restoring bogs needs to take into account elevated release from fresh Sphagnum peat as well as from sedges growing on decomposed peat. Given the high atmospheric nitrogen deposition, restoration will not be able to achieve an oligotrophic ecosystem in the short term.

  13. Recent atmospheric dust deposition in an ombrotrophic peat bog in Great Hinggan Mountain, Northeast China.

    PubMed

    Bao, Kunshan; Xing, Wei; Yu, Xiaofei; Zhao, Hongmei; McLaughlin, Neil; Lu, Xianguo; Wang, Guoping

    2012-08-01

    Recent deposition of atmospheric soil dust (ASD) was studied using (210)Pb-dated Sphagnum-derived peat sequences from Great Hinggan Mountain in northeast China. Physicochemical indices of peat including dry bulk density, water content, ash content, total organic carbon and mass magnetic susceptibility were measured. Acid-insoluble concentration of lithogenic metals (Al, Ca, Fe, Mn, V and Ti) were measured using ICP-AES. The basic physicochemical properties were used to assess the peat trophic status and indicated that the sections above 45-60 cm are rain-fed peat. A continuous record of ASD fluxes over the past 150 years was reconstructed based on the geochemical data obtained from the ombrotrophic zone, and the average input rate of ASD is 13.4-68.1 g m(-2) year(-1). The source of soil dust deposited in peat was dominated by the long-range transport of mineral aerosol from the drylands in north China and Mongolia. The temporal variation of ASD fluxes in the last 60 years coincides well with the meteorological records of dust storm frequency during 1954-2002 in north China. This suggests that the reconstructed sequence of atmospheric dust deposition is reliable and we can look back in time at the dust evolution before 1949. Dust storm events were observed occasionally in the late Qing dynasty, and their frequency and intensity were smaller than dust weather occurring in recent times. Four peaks of ASD fluxes were distinguished and correlated with the historical events at that time. This study presents the first atmospheric soil dust data in peat records in northeast China, and complements a global database of peat bog archives of atmospheric deposition. The results reflect the patterns of local environmental change over the past century in north China and will be helpful in formulating policies to achieve sustainable and healthy development. PMID:22664536

  14. Potassium and phosphorus additions modify the response of Sphagnum capillifolium growing on a Scottish ombrotrophic bog to enhanced nitrogen deposition

    Microsoft Academic Search

    J. A. Carfrae; L. J. Sheppard; J. A. Raven; I. D. Leith; A. Crossley

    2007-01-01

    This study reports the impacts of wet reduced versus oxidised N on in situ responses of Sphagnum capillifolium: architecture, chemistry and Fv\\/Fm. Nitrogen inputs were enhanced under realistic treatment scenarios in a unique experiment on an ombrotrophic bog ecosystem in the Scottish Borders, UK, receiving, historically and currently, low pollutant deposition. Ammonium (NH4Cl) and nitrate (NaNO3) treatments were applied from

  15. Determination of atmospheric nitrogen deposition to a semi-natural peat bog site in an intensively managed agricultural landscape

    NASA Astrophysics Data System (ADS)

    Hurkuck, Miriam; Brümmer, Christian; Mohr, Karsten; Grünhage, Ludger; Flessa, Heinz; Kutsch, Werner L.

    2014-11-01

    Rising levels of atmospheric nitrogen (N) deposition have been found to affect the primary productivity and species composition of most terrestrial ecosystems. Highly vulnerable ecosystems such as nutrient-poor bogs are expected to respond to increasing N input rates with a decrease in plant species diversity. Our study site - a moderately drained raised bog and one of only very few remaining protected peatland areas in Northwestern Germany - is surrounded by highly fertilised agricultural land and intensive livestock production. We quantified the annual deposition of atmospheric N over a period of two years. Dry deposition rates of different N species and their reactants were calculated from day and night-time concentrations measured by a KAPS denuder filter system. Dry N deposition amounted to 10.9 ± 1.0 kg N ha-1 yr-1 (year 1) and 10.5 ± 1.0 kg N ha-1 yr-1 (year 2). More than 80% of total deposited N was attributed to ammonia (NH3). A strong seasonality in NH3 concentrations and depositions could be observed. Day and night-time concentrations and depositions, however, did not differ significantly. Total N deposition including bulk N deposition resulted in about 25 kg N ha-1 yr-1. Our results suggest that the intensive agricultural land management of surrounding areas and strongly emitting animal husbandry lead to N inputs into the protected peatland area that exceed the ecosystem's specific critical load up to fivefold. This gives rise to the assumption that a further shift in plant species composition with a subsequent alteration of the local hydrological regime can be expected.

  16. Retention of As and Sb in ombrotrophic peat bogs: records of As, Sb, and Pb deposition at four Scottish sites.

    PubMed

    Cloy, Joanna M; Farmer, John G; Graham, Margaret C; MacKenzie, Angus B

    2009-03-15

    Possible postdepositional As migration in ombrotrophic peat bogs was investigated by comparing depth profiles of As with those of Sb and Pb, two elements considered to be essentially immobile in peat, and those of redox-sensitive, potentially mobile nutrient elements such as Mn, Fe, P, and S in 210Pb-dated cores from four Scottish bogs. Concentration profiles of As were similar to those of Sb and Pb rather than these other elements, indicating that As is bound strongly to organic matter and is relatively immobile in ombrotrophic peat. Historical records of atmospheric anthropogenic As, Sb, and Pb deposition during the industrial and postindustrial periods were derived, site-specific maxima (up to 1.55, 1.33, and 45 mg m(-2) y(-1), respectively) occurring between the late 1890s and 1960s, reflecting emissions from diverse sources such as mining and smelting, coal combustion, and also, in the case of Pb, exhaust emissions from the use of leaded gasoline. Since the mid-1980s, fluxes of Pb decreased (4-7 fold) more rapidly than those of As and Sb (2-3 fold), attributable to both the gradual elimination of leaded gasoline and recent new sources of the latter elements. Relative trends in derived anthropogenic As, Sb, and Pb deposition largely agreed with other Scottish peat and moss archive records, direct measurements of deposition, and UK emissions, i.e., four different types of data source. PMID:19368168

  17. Retention of As and Sb in ombrotrophic peat bogs: records of As, Sb, and Pb deposition at four Scottish sites

    SciTech Connect

    Joanna M. Cloy; John G. Farmer; Margaret C. Graham; Angus B. MacKenzie [University of Edinburgh, Edinburgh (United Kingdom). School of GeoSciences

    2009-03-15

    Possible postdepositional As migration in ombrotrophic peat bogs was investigated by comparing depth profiles of As with those of Sb and Pb, two elements considered to be essentially immobile in peat, and those of redox-sensitive, potentially mobile nutrient elements such as Mn, Fe, P, and S in {sup 210}Pb-dated cores from four Scottish bogs. Concentration profiles of As were similar to those of Sb and Pb rather than these other elements, indicating that As is bound strongly to organic matter and is relatively immobile in ombrotrophic peat. Historical records of atmospheric anthropogenic As, Sb, and Pb deposition during the industrial and postindustrial periods were derived, site-specific maxima (up to 1.55, 1.33, and 45 mg m{sup -2} y{sup -1}, respectively) occurring between the late 1890s and 1960s, reflecting emissions from diverse sources such as mining and smelting, coal combustion, and also, in the case of Pb, exhaust emissions from the use of leaded gasoline. Since the mid-1980s, fluxes of Pb decreased (4-7 fold) more rapidly than those of As and Sb (2-3 fold), attributable to both the gradual elimination of leaded gasoline and recent new sources of the latter elements. Relative trends in derived anthropogenic As, Sb, and Pb deposition largely agreed with other Scottish peat and moss archive records, direct measurements of deposition, and UK emissions, i.e., four different types of data source. 36 refs., 3 figs., 1 tab.

  18. 14 C AMS wiggle matching of raised bog deposits and models of peat accumulation

    Microsoft Academic Search

    M. R. Kilian; B. van Geel; J. van der Plicht

    2000-01-01

    High-resolution Accelerator Mass Spectrometer (AMS) 14C dates of selected plant macrofossils from the raised bog Engbertsdijksvenen (Eastern Netherlands) show century-scale wiggles analogous to the radiocarbon calibration curve. We used three relative time scales, viz., based on depth, mass, and pollen concentration, respectively, to match the peat AMS dates to the calibration curve. This procedure is repeated for one conventionally dated

  19. Inputs of Nitrogen to Bogs of Alberta, Canada: the Importance of Biological Nitrogen Fixation VS. Atmospheric Deposition from Oil Sands Mining

    NASA Astrophysics Data System (ADS)

    Prsa, T.; Vile, M. A.; Wieder, R.; Vitt, D. H.

    2010-12-01

    Bogs of Alberta, Canada are peatlands that are both Sphagnum-moss dominated and nutrient limited. Due to their ombrotrophic nature, nitrogen (N) is deposited only via atmospheric deposition (wet/dry) and biological N2 fixation. Historically, bogs of Alberta are unpolluted with low rates of atmospheric N deposition (< 1 kg ha-1 yr-1), as opposed to eastern Canada and western Europe where rates are considerably higher (>15 kg ha-1 yr-1). Due to the extensive rich bitumen deposits under northern Alberta, however, the Oil Sands Mining (OSM) industry has been growing exponentially since the late 1960’s. Bogs situated near OSM, therefore, are likely to experience increased N deposition and the consequences and impacts of such a phenomenon are as yet, unknown. Additional N inputs into these N-limited ecosystems may cause an imbalance in the N-cycle, specifically, biological N2 fixation. Our goal was to quantify inputs of N to the system from both rates of biological N2 fixation and bulk atmospheric deposition. In summer 2010, we used acetylene reduction assay (ARA) to indirectly measure N2 fixation rates in the four most abundant moss species: Sphagnum fuscum, S. capillifolium, S. angustifolium and Pleurozium schreberi at three bog sites varying in proximity to OSM: McMurray, McKay and Utikuma bog (51, 24 and 300 km, respectively) throughout the growing season (May-August comprising 6 sampling efforts). We measured atmospheric N deposition with ion exchange resin columns (10 per site). An ANOVA and subsequent ad hoc test indicated that Utikuma had significantly lower atmospheric N deposition rates (0.130 ± 0.19 mg m-2 d-1; µ ± SE) than both McMurray and McKay (0.337 ± 0.03 and 0.262 ± 0.03 mg m-2 da-1, respectively; F2,24 = 9.04, p<0.0012), demonstrating that sites closest to the OSM region do exhibit higher rates of atmospheric N deposition. Alternatively, for inputs of N via N2 fixation, we found that McMurray (700.6 ± 144.7 µmol m-2 da-1) had significantly higher ARA rates than McKay and Utikuma (205.8 ± 27.9 and 376.7 ± 73.9 µmol m-2 da-1, respectively; F2,264 = 7.60, p<0.0006). A one-way ANOVA showed significant differences in ARA rates among moss species (F2,263 = 7.60, p<0.0006). Duncan’s multiple range test indicated that S. fuscum and S. capillifolium hummocks had significantly higher rates (768.5 ± 138.3 and 495.8 ± 115.5 µmol m-2 da-1, respectively), as compared to S. angustifolium and P. schreberi (284.9 ± 45.5 and 24.9 ± 5.6 µmol m-2 da-1, respectively). Peak rates were recorded in mid-June and early July (678.1 ± 127.2 and 1009.7 ± 263.9 µmol m-2 da-1, respectively) across all the sites (F5,228 = 5.68, p<0.0001). This study is the first to simultaneously examine N2 fixation in a variety of mosses and atmospheric N inputs in Alberta bogs located close to OSM over a growing season. Our results suggest that despite increased N deposition, N2 fixation continues to represent the dominant input of N into Alberta’s bogs. In addition to S. fuscum and S. capillifolium being the prevalent hosts for N2-fixers, these species comprise the highest percent cover of Alberta’s bogs (~80%).

  20. Historical records of atmospheric metal deposition along the St. Lawrence Valley (eastern Canada) based on peat bog cores

    NASA Astrophysics Data System (ADS)

    Pratte, Steve; Mucci, Alfonso; Garneau, Michelle

    2013-11-01

    The recent history of atmospheric As, Cd, Ni, Pb and Zn deposition and the stable Pb isotope signatures were reconstructed from short cores collected at three peat bogs along the St. Lawrence Valley (SLV). The onset of industrial activity was recorded around 1810-1850 AD. As, Cd, Pb and, to a certain extent, Ni deposition rates reached maxima between 1940 and the early 1970s. Trace metals likely originated from coal-burning and ore smelting between 1850 and 1950 AD, and were replaced thereafter, at least in the case of Pb, by the combustion of leaded gasolines until the mid-1980s. Trace metal contents and accumulation rates were greater in the two cores recovered from the southwestern SLV than further northeast, as expected from their proximity to urban and industrial centers of eastern Canada and the U.S. Mid-West and the direction of the prevalent winds. A rapid decrease in metal accumulation rates since the 1970s suggests that mitigation policies were effective in reducing atmospheric metal emissions. Nevertheless, metal accumulation rates and stable Pb isotope signatures have not yet returned to their pre-industrial values.

  1. Two thousand years of atmospheric arsenic, antimony, and lead deposition recorded in an ombrotrophic peat bog profile, Jura Mountains, Switzerland

    Microsoft Academic Search

    William Shotyk; Andrij K. Cheburkin; Peter G. Appleby; Andreas Fankhauser; Jan D. Kramers

    1996-01-01

    A peat core from a Swiss bog reveals significant enrichments of As, Sb and Pb extending back to Roman times, indicating that the anthropogenic fluxes of these metals have exceeded the natural fluxes for more than 2000 years. The isotopic composition of Pb provides no evidence of vertical downward Pb migration, suggesting that the bog has faithfully preserved the historical

  2. Reconnaissance of Colorado Front Range bogs for uranium and other elements

    SciTech Connect

    Owen, D.E.; Schumann, R.R.; Otton, J.K.

    1987-08-01

    Alpine bogs form along spring-fed valley floors and in steam drainages restricted by moraines, slides, and beaver dams. The bogs are generally young (Holocene) and contain a few tens of centimeters to several meters of peat and organic-rich muck. Organic matter has a great affinity for cations such as uranium; the geochemical enrichment factor between the peats and uraniferous ground water can approach 10,000 to 1. Because the bog sediments are geologically young, the uranium is in gross disequilibrium and has low radioactivity, thus it is undetectable by ground and aerial gamma surveys. Communities that derive a part of their water supplies from drainages containing uraniferous bogs face a potential health threat because the uranium is loosely bound and may easily be remobilized by ground water moving through the bogs. Reconnaissance sampling of bogs was conducted in the Colorado Front Range from the South Park area to the Colorado-Wyoming state line. Several bogs have uranium concentrations of 1000-3000 ppm, but most bogs have uranium concentrations in the 10-100 ppm range. Zinc concentrations of 100-1000 ppm are found in some bogs and many other metallic elements are present in concentrations between 10 and 100 ppm. Concentrations between 100 and 1000 ppm of some of the rare earth elements (e.g., Ce, La, Nd, Yb) were found in the Cripple Creek area.

  3. Past atmospheric deposition of metals in northern Indiana measured in a peat core from Cowles bog

    Microsoft Academic Search

    Kenneth L. Cole; Daniel R. Engstrom; Richard P. Futyma; Robert Stottlemyer

    1990-01-01

    A peat core from a calcareous fen was used to assess past metal accumulation from atmospheric sources in northern Indiana. Total concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn were measured at intervals along the core, which were dated by ²¹°Pb, radiocarbon, and pollen analysis. The deposition of airborne metal particulates rose dramatically from

  4. Long-term nitrogen deposition increases phosphorus limitation of bryophytes in an ombrotrophic bog

    Microsoft Academic Search

    Mukunda Phuyal; Rebekka R. E. Artz; Lucy Sheppard; Ian D. Leith; David Johnson

    2008-01-01

    Here we investigate the effect of 4 years simulated atmospheric deposition of ammonium (NH4) and nitrate (NO3), applied alone or in combination with phosphorus and potassium (PK), on the surface phosphatase activities and nutrient\\u000a acquisition behaviour of two species of moss (Sphagnum\\u000a capillifolium and Hypnum jutlandicum) from an ombrotrophic peatland. Phosphatase activity was significantly enhanced by both the NH4 and

  5. A new approach for quantifying cumulative, anthropogenic, atmospheric lead deposition using peat cores from bogs: Pb in eight Swiss peat bog profiles

    Microsoft Academic Search

    W. Shotyk; P. Blaser; A. Grünig; A. K. Cheburkin

    2000-01-01

    Peat cores taken from eight Swiss peatlands were used to calculate inventories of anthropogenic Pb using either Sc or Zr to quantify Pb derived from rock weathering. The shapes of the Pb\\/Sc and Pb\\/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at all sites. At one of the sites (Etang de la Gruère), anthropogenic Pb was calculated

  6. Lead in Three Peat Bog Profiles, Jura Mountains, Switzerland: Enrichment Factors, Isotopic Composition, and Chronology of Atmospheric Deposition

    Microsoft Academic Search

    W. Shotyk; A. K. Cheburkin; P. G. Appleby; A. Fankhauser; J. D. Kramers

    1997-01-01

    One metre cores were taken from three peat bogs in the Jura Mountains of Switzerland: Etang de la Gruère (EGr), La Tourbière des Genevez (TGe), and Praz Rodet (PRd). Dried peat samples were analyzed for lead (Pb) using the EMMA XRF and scandium (Sc) using INAA. Enrichment factors (EF) were calculated by normalizing to the background Pb\\/Sc ratio at EGr.

  7. Grass species influence on plant N uptake - Determination of atmospheric N deposition to a semi-natural peat bog site using a 15N labelling approach

    NASA Astrophysics Data System (ADS)

    Hurkuck, Miriam; Brümmer, Christian; Spott, Oliver; Flessa, Heinz; Kutsch, Werner L.

    2014-05-01

    Large areas of natural peat bogs in Northwestern Germany have been converted to arable land and were subjected to draining and peat cutting in the past. The few protected peatland areas remaining are affected by high nitrogen (N) deposition. Our study site - a moderately drained raised bog - is surrounded by highly fertilized agricultural land and livestock production. In this study, we used a 15N pool dilution technique called 'Integrated Total Nitrogen Input' (ITNI) to quantify annual deposition of atmospheric N into biomonitoring pots over a two-year period. Since it considers direct N uptake by plants, it was expected to result in higher N input than conventional methods for determination of N deposition (e.g. micrometeorological approaches, bulk N samplers). Using Lolium multiflorum and Eriophorum vaginatum as monitor plants and low, medium and high levels of fertilization, we aimed to simulate increasing N deposition to planted pots and to allocate airborne N after its uptake by the soil-plant system in aboveground biomass, roots and soil. Increasing N fertilization was positively correlated with biomass production of Eriophorum vaginatum, whereas atmospheric plant N uptake decreased and highest airborne N input of 899.8 ± 67.4 µg N d-1 pot-1 was found for low N fertilization. In contrast, Lolium multiflorum showed a clear dependency of N supply on plant N uptake and was highest (688.7 ± 41.4 µg N d-1 pot-1) for highly fertilized vegetation pots. Our results suggest that grass species respond differently to increasing N input. While crop grasses such as Lolium multiflorum take up N according to N availability, species adopted to nutrient-limited conditions like Eriophorum vaginatum show N saturation effects with increasing N supply. Total airborne N input ranged from about 24 to 66 kg N ha-1 yr-1 dependent on the used indicator plant and the amount of added fertilizer. Parallel determination of atmospheric N deposition using a micrometeorological approach complemented with bulk samplers was about 24 kg N ha-1 yr-1 during both years of experiments and was thus at the lower range of results obtained by the ITNI method. The low 15N recovery rate of about 50 % during some experiments indicated an underestimation of the applied ITNI approach, resulting in a maximum possible N uptake of twice as high as the determined N input. Most likely, the intensive agricultural land management of the surrounding areas leads to this high N deposition into the protected peatland area. As a result, increasing sensitivity of ombrotrophic vegetation with a subsequent change in plant species composition and a decline in bog-specific vegetation cannot be excluded.

  8. Experimental nitrogen, phosphorus, and potassium deposition decreases summer soil temperatures, water contents, and soil CO2 concentrations in a northern bog

    NASA Astrophysics Data System (ADS)

    Wendel, S.; Moore, T.; Bubier, J.; Blodau, C.

    2010-08-01

    Ombrotrophic peatlands depend on airborne nitrogen (N), whose deposition has increased in the past and lead to disappearance of mosses and increased shrub biomass in fertilization experiments. The response of soil water content, temperature, and carbon gas concentrations to increased nutrient loading is poorly known and we thus determined these data at the long-term N fertilization site Mer Bleue bog, Ontario, during a two month period in summer. Soil temperatures decreased with NPK addition in shallow peat soil primarily during the daytime (t-test, p<0.05) owing to increased shading, whereas they increased in deeper peat soil (t-test, p<0.05), probably by enhanced thermal conductivity. RMANOVA suggested interactions between N and PK addition in particular soil layers and strong interactions between soil temperatures and volumetric water contents (p<0.05). Averaged over all fertilized treatments, the mean soil temperatures at 5 cm depth decreased by 1.3 °C and by 4.7 °C (standard deviation 0.9 °C) at noon. Water content was most strongly affected by within-plot spatial heterogeneity but also responded to both N and PK load according to RMANOVA (p<0.05). Overall, water content and CO2 concentrations in the near-surface peat (t-test, p<0.05) were lower with increasing N load, suggesting more rapid soil gas exchange. The results thus suggest that changes in bog ecosystem structure with N deposition have significant ramifications for physical parameters that in turn control biogeochemical processes.

  9. Experimental nitrogen, phosphorus, and potassium deposition decreases summer soil temperatures, water contents, and soil CO2 concentrations in a northern bog

    NASA Astrophysics Data System (ADS)

    Wendel, S.; Moore, T.; Bubier, J.; Blodau, C.

    2011-03-01

    Ombrotrophic peatlands depend on airborne nitrogen (N), whose deposition has increased in the past and lead to disappearance of mosses and increased shrub biomass in fertilization experiments. The response of soil water content, temperature, and carbon gas concentrations to increased nutrient loading is poorly known and we thus determined these data at the long-term N fertilization site Mer Bleue bog, Ontario, during a two month period in summer. Soil temperatures decreased with NPK addition in shallow peat soil primarily during the daytime (t-test, p < 0.05) owing to increased shading, whereas they increased in deeper peat soil (t-test, p < 0.05), probably by enhanced thermal conductivity. These effects were confirmed by RMANOVA, which also suggested an influence of volumetric water contents as co-variable on soil temperature and vice versa (p < 0.05). Averaged over all fertilized treatments, the mean soil temperatures at 5 cm depth decreased by 1.3 °C and by 4.7 °C (standard deviation 0.9 °C) at noon. Water content was most strongly affected by within-plot spatial heterogeneity but also responded to both N and PK load according to RMANOVA (p < 0.05). Overall, water content and CO2 concentrations in the near-surface peat (t-test, p < 0.05) were lower with increasing N load, suggesting more rapid soil gas exchange. The results thus suggest that changes in bog ecosystem structure with N deposition have significant ramifications for physical parameters that in turn control biogeochemical processes.

  10. Inertia in an ombrotrophic bog ecosystem in response to 9 years' realistic perturbation by wet deposition of nitrogen, separated by form.

    PubMed

    Sheppard, Lucy J; Leith, Ian D; Mizunuma, Toshie; Leeson, Sarah; Kivimaki, Sanna; Neil Cape, J; van Dijk, Netty; Leaver, David; Sutton, Mark A; Fowler, David; Van den Berg, Leon J L; Crossley, Alan; Field, Chris; Smart, Simon

    2014-02-01

    Wet deposition of nitrogen (N) occurs in oxidized (nitrate) and reduced (ammonium) forms. Whether one form drives vegetation change more than the other is widely debated, as field evidence has been lacking. We are manipulating N form in wet deposition to an ombrotrophic bog, Whim (Scottish Borders), and here report nine years of results. Ammonium and nitrate were provided in rainwater spray as NH4 Cl or NaNO3 at 8, 24 or 56 kg N ha(-1)  yr(-1) , plus a rainwater only control, via an automated system coupled to site meteorology. Detrimental N effects were observed in sensitive nonvascular plant species, with higher cumulative N loads leading to more damage at lower annual doses. Cover responses to N addition, both in relation to form and dose, were species specific and mostly dependent on N dose. Some species were generally indifferent to N form and dose, while others were dose sensitive. Calluna vulgaris showed a preference for higher N doses as ammonium N and Hypnum jutlandicum for nitrate N. However, after 9 years, the magnitude of change from wet deposited N on overall species cover is small, indicating only a slow decline in key species. Nitrogen treatment effects on soil N availability were likewise small and rarely correlated with species cover. Ammonium caused most N accumulation and damage to sensitive species at lower N loads, but toxic effects also occurred with nitrate. However, because different species respond differently to N form, setting of ecosystem level critical loads by N form is challenging. We recommend implementing the lowest value of the critical load range where communities include sensitive nonvascular plants and where ammonium dominates wet deposition chemistry. In the context of parallel assessment at the same site, N treatments for wet deposition showed overall much smaller effects than corresponding inputs of dry deposition as ammonia. PMID:24038771

  11. Bog iron formation in the Nassawango Creek watershed, Maryland, USA

    USGS Publications Warehouse

    Bricker, O.P.; Newell, W.L.; Simon, N.S.

    2004-01-01

    The Nassawango bog ores in the modern environment for surficial geochemical processes were studied. The formation of Nassawango bog ores was suggested to be due to inorganic oxidation when groundwater rich in ferrous iron emerges into the oxic, surficial environment. It was suggested that the process, providing a phosphorus sink, may be an unrecognized benefit for mitigating nutrient loading from agricultural lands. It is found that without the effect of iron fixing bacteria, bog deposites could not form at significant rates.

  12. Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland - article no. GB2016

    SciTech Connect

    Cloy, J.M.; Farmer, J.G.; Graham, M.C.; MacKenzie, A.B.; Cook, G.T. [University of Edinburgh, Edinburgh (United Kingdom). School for Geoscience

    2008-05-15

    Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (C-14, Pb-210) and analyzed (ICP-OES, ICP-MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e. g., Pb-206/Pb-207), clear indications of Pb contamination during the pre-Roman/Roman, post-Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were the most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian-Pb-influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the post industrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (similar to 10 to 40 mg m{sup -2} a{sup -1}) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m{sup 2} a{sup -1} by the early 2000s.

  13. Nature and origins of acidity in bogs

    SciTech Connect

    Urban, N.R.

    1987-01-01

    To elucidate the causes of acidity in bogs, all of the processes generating and consuming acidity in a small peat bog in northern Minnesota were measured. These processes include ion exchange, plant nutrient uptake, atmospheric deposition, decomposition, organic acid production, sulfate reduction, and denitrification. Organic acid production was found to be the dominant source of acidity, responsible for the low pH of bog waters and the high acidity in the outflow. Net biological uptake (NBU) is the next largest source of acidity. Ion exchange accounts for only about 40% of the NBU-acidity. Plant uptake and ion exchange are much larger sources of acidity on an annual basis, but much of this acidity is neutralized by decomposition. Sulfate reduction and denitrification are quantitatively unimportant at this site because inputs (NO/sub 3//sup -/ and SO/sub 4/=) are low. Bog water samples and peat cores from bogs across northeastern North America were analyzed to determine if geographic trends in the rates of acidity-generating and -consuming processes exist. Rates of organic acid production varied little across the transect. Higher values of NBU-acidity were observed in maritime bogs than in midcontinental bogs. The effects of transformations of sulfur and nitrogen on the hydrogen-ion cycle were examined in detail. Nitrate appears to be taken up by bryophytes and little is lost to denitrification. Alkalinity from nitrate uptake is low. In contrast, there is a dynamic cycle of oxidation and reduction of sulfur within bogs. Inorganic forms of sulfur are not important storage pools in peat; 35% of the total sulfur input is accumulated as organic S.

  14. The Vanishing Bog.

    ERIC Educational Resources Information Center

    Hanif, Muhammad

    1990-01-01

    Directions for the construction of a model bog habitat are provided including examples of plants and animals which may be suitable. Activities that use this model are suggested. Background information on the ecology and chemistry of the bog is included. (CW)

  15. Skeletal analysis and comparison of bog bodies from Northern European peat bogs

    NASA Astrophysics Data System (ADS)

    Pestka, Jan M.; Barvencik, Florian; Beil, Frank T.; Marshall, Robert P.; Jopp, Eilin; Schilling, Arndt F.; Bauerochse, Andreas; Fansa, Mamoun; Püschel, Klaus; Amling, Michael

    2010-04-01

    Although numerous bodies were deposited in Western European bogs in the past centuries, few were found and underwent archeological analysis. No studies comparing skeletal structure and mineralization of bog bodies from different ages have been performed to this day. Therefore, the aim of this study was to analyze and compare skeletal features and specifics of the human remains of three bog bodies from the Iron and Middle Ages found in Northern European peat bogs. Demineralization due to the acidic environment in peat bogs was comparably pronounced in all three bodies. Still, the macroscopic state of skeletal preservation was excellent. In addition to contact radiography, we used peripheral quantitative computed tomography to measure cortical bone mineral density. The conservation of skeletal three-dimensional microstructural elements was assessed by high-resolution microcomputed tomography analysis. These techniques revealed severe differences in bone mineral density and enabled us to determine handedness in all three bodies. Additionally, unique skeletal features like intravital bone lesions, immobilization osteoporosis, and Harris lines were found. A deformity of the left femoral head was observed which had the typical appearance of an advanced stage of Legg-Calve-Perthes disease. This study gives detailed insight into the skeletal microstructure and microarchitecture of 800- to 2,700-year-old bog bodies. Skeletal analysis enables us to draw conclusions not only concerning changes in the acidic environment of the bog, but also serves as a diagnostic tool to unravel life circumstances and diseases suffered by humans in the Iron and Middle Ages.

  16. The Mongghul Bog Ritual

    E-print Network

    Limusishiden; Jugui

    ???????????????? Tape No. / Track / Item No. Mongghul Various 10.MP4 Length of track 01:10:32 Related tracks (include description/relationship if appropriate) Title of track The Mongghul Bog Ritual ??????? ????????????????? Translation of title Description... (to be used in archive entry) The Bog ritual is held during the winter in Mongghul communities in order to delight local territorial deities. In 1998, the village had 760 residents, all of whom were Mongghul. Some said their ancestors were...

  17. Investigating Bogs: An Interdisciplinary Adventure.

    ERIC Educational Resources Information Center

    Pankiewicz, Philip R.; Schneider, Lois

    1995-01-01

    Presents the case for the use of bogs as ideal sites for hundreds of interdisciplinary lessons that combine chemistry, geology, various branches of biology, and wetlands archaeology. Includes general guidelines to aid in the design of interdisciplinary bog studies. (DDR)

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

    Microsoft Academic Search

    Juul Limpens; Hilde B. M. Tomassen; Frank Berendse

    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 four of their accompanying species to changes in N deposition.

  19. Biomolecules in Maine bogs

    Microsoft Academic Search

    Jennifer Dinn

    1994-01-01

    The field of natural products chemistry is a new aspect of chemistry at Colby. The search for bioactive compounds in Sphagnum has been given minimal attention in the realm of natural products chemistry at Colby. Six samples of Sphagnum magellanicum , taken from varying depths of the peat mat, were gathered from the Great Bog, in Belgrade, ME. The depths

  20. Chemical records of environmental pollution in ombrotrophic peat bogs 

    E-print Network

    Cloy, Joanna Marie

    2006-11-28

    and environmental health. In recent years ombrotrophic peat bogs have been used to study the changing rates and sources of atmospheric metal deposition, as they receive all their water and nutrients from the atmosphere by dry and wet deposition alone. Cores from...

  1. Hydrological differences between bogs and bog-relicts and consequences for bog restoration

    Microsoft Academic Search

    J. M. Schouwenaars

    1993-01-01

    The hydrology of bog relicts differs from that in undisturbed bogs. The surface layers of these relicts mostly consist of\\u000a moderately to strongly humified, secondary weathered peat as a result of drainage and peat cutting. The hydrophysical properties\\u000a of these layers cause relatively high groundwater level fluctuations.\\u000a \\u000a Deep drainage systems, both in the bog relicts and in their surroundings, may

  2. Effects of elevated CO2 and vascular plants on evapotranspiration in bog vegetation

    Microsoft Academic Search

    Monique M. P. D. Heijmans; Wim J. Arp; Frank Berendse

    2001-01-01

    We determined evapotranspiration in three experiments designed to study the effects of elevated CO2 and increased N deposition on ombrotrophic bog vegetation. Two experiments used peat monoliths with intact bog vegetation in containers, with one experiment outdoors and the other in a greenhouse. A third experiment involved monocultures and mixtures of Sphagnum magellanicum and Eriophorum angustifolium in containers in the

  3. Estimating methane production rates in bogs and landfills by deuterium enrichment of pore water

    Microsoft Academic Search

    D. I. Siegel; J. P. Chanton; P. H. Glaser; L. S. Chasar; D. O. Rosenberry

    2001-01-01

    Raised bogs and municipal waste landfills harbor large populations of methanogens within their domed deposits of anoxic organic matter. Although the methane emissions from these sites have been estimated by various methods, limited data exist on the activity of the methanogens at depth. We therefore analyzed the stable isotopic signature of the pore waters in two raised bogs from northern

  4. The geochemistry of major and selected trace elements in a forested peat bog, Kalimantan, SE Asia, and its implications for past atmospheric dust deposition

    Microsoft Academic Search

    Dominik Weiss; William Shotyk; Jack Rieley; Susan Page; Marlies Gloor; Steve Reese; Antonio Martinez-Cortizas

    2002-01-01

    Biogeochemical processes in a forested tropical peat deposit and its record of past atmospheric dust deposition were assessed using the vertical distribution of lithophilic and plant essential elements in a dated core profile from Borneo, SE Asia. Peat formation started ?22,120 14C yr before present (BP), and Ca\\/Mg mass ratios of the solid peat and very low ash contents indicate

  5. Dating raised bogs: New aspects of AMS 14C wiggle matching, a reservoir effect and climatic change

    Microsoft Academic Search

    M. R. Kilian; J. VAN DER PLICHTf; B. Van Geel

    1995-01-01

    High resolution AMS dating of Holocene raised bog deposits (Engbertsdijksvenen, The Netherlands) shows natural 14C variations (wiggles) which can be matched with the dendrochronological calibration curve. Comparison of our results with other, conventionally dated peat cores and the ?14C record shows an unexpected and as yet unreported reservoir effect, and a marked and sudden wetting of the bog surfaces coinciding

  6. Pollen analysis of Patschke bog 

    E-print Network

    Camper, Hope Armstrong

    1991-01-01

    ), Rhexia mariana L. var. mariana (water P ' * ), D' d' ~ L. (b tto d), d H~~L. (hdt. Job' t). Another small forested area lies northeast of the bog. 1'h do ' t t M~ Hl t M 'h. . Bl t (black gum) with an understory of yaupon holly and wax myrtle. Both...

  7. Pollen analysis of Patschke bog

    E-print Network

    Camper, Hope Armstrong

    1991-01-01

    * (P PP Bo h ~1' d ' (L. ) BW. (bog h p), E '1 gl w lt. ( t-b ' ), d M'k ' d (L. l W'lid. (1)~'ghp0). Wodd'~(L)N (V' g' ' h fl'), 0 d ~1L. (Ryl f Osmunda cinnamomea L. (Cinnamon fern), and Juncus effusus L. var. solutus Fern. & Wieg. (soft rush... of the pond has a 20 foot marshy border of black mucky soil before the pasture begins. Along the shoreline grows pthof~Shp. (phg), J ff L. var. ~~s Fern. & Wieg. (soft rush), ~Xris ~ustice' Rich. (y 11o ? ydg ), P E tt (Ell. ) E 11 (water smartweed...

  8. Paired charcoal and tree-ring records of high-frequency Holocene fire from two New Mexico bog sites

    USGS Publications Warehouse

    Allen, C.D.; Anderson, R. Scott; Jass, R.B.; Toney, J.L.; Baisan, C.H.

    2008-01-01

    Two primary methods for reconstructing paleofire occurrence include dendrochronological dating of fire scars and stand ages from live or dead trees (extending back centuries into the past) and sedimentary records of charcoal particles from lakes and bogs, providing perspectives on fire history that can extend back for many thousands of years. Studies using both proxies have become more common in regions where lakes are present and fire frequencies are low, but are rare where high-frequency surface fires dominate and sedimentary deposits are primarily bogs and wetlands. Here we investigate sedimentary and fire-scar records of fire in two small watersheds in northern New Mexico, in settings recently characterised by relatively high-frequency fire where bogs and wetlands (Chihuahuen??os Bog and Alamo Bog) are more common than lakes. Our research demonstrates that: (1) essential features of the sedimentary charcoal record can be reproduced between multiple cores within a bog deposit; (2) evidence from both fire-scarred trees and charcoal deposits documents an anomalous lack of fire since ???1900, compared with the remainder of the Holocene; (3) sedimentary charcoal records probably underestimate the recurrence of fire events at these high-frequency fire sites; and (4) the sedimentary records from these bogs are complicated by factors such as burning and oxidation of these organic deposits, diversity of vegetation patterns within watersheds, and potential bioturbation by ungulates. We consider a suite of particular challenges in developing and interpreting fire histories from bog and wetland settings in the Southwest. The identification of these issues and constraints with interpretation of sedimentary charcoal fire records does not diminish their essential utility in assessing millennial-scale patterns of fire activity in this dry part of North America. ?? IAWF 2008.

  9. Restoring afforested peat bogs: results of current research

    E-print Network

    Restoring afforested peat bogs: results of current research The value of peat bogs as open habitats may suffice on lowland raised bogs. Damming furrows is ineffective if the peat is severely cracked sundew, Drosera anglica #12;Introduction In their natural state, peat bogs provide unique habitats

  10. The butterfly fauna of Wisconsin bogs: lessons for conservation

    Microsoft Academic Search

    Ann B. SwengelScott; Scott R. Swengel

    2010-01-01

    During 2002–2009, we surveyed butterflies at 73 bogs, 20 adjacent lowland roadsides, and 5 nearby upland roadsides in northern\\u000a Wisconsin and three bogs in central Wisconsin, with additional observations from 1986 to 2001. Especially in northern Wisconsin,\\u000a bogs are relatively unaffected by humans, but naturally comprise <1% of the landscape. Bog specialist species composition\\u000a varied by bog type (muskeg, kettlehole,

  11. Explosive silicic eruptions in Iceland: from vent to peat bog

    E-print Network

    Explosive silicic eruptions in Iceland: from vent to peat bog OUTLINE Microtephra horizons, found be found in peat bogs and lake sediments across Scotland and the rest of Northern Europe (Figure 1; Larsen

  12. Titanium in ombrotrophic Sphagnum mosses from various peat bogs of Germany and Belgium.

    PubMed

    Kempter, Heike; Frenzel, Burkhard

    2008-03-25

    Titanium concentrations and Ti inventories (total Ti in the sample) in living Sphagnum mosses from the surfaces of eight ombrotrophic peat bogs of five different regions of Germany and Belgium were studied over a period of two years (1995-7). Six to ten peat moss samples with a given surface area (100 cm2) and length (5 cm) were collected at different sites in the peat bogs studied several times (every six weeks to three months) during a year. Variability of Ti concentrations and inventories were determined within each peat bog for the species S. magellanicum, S. rubellum, S. papillosum, and S. cuspidatum, for the microhabitats 'lawn', 'slope' and 'hollow', as well as for the studied peat bogs of different regions and for each season. Likewise, Ti concentration values were determined for the moss plant segments: 'capitulum', 'living green' and 'dead brown'. Ti concentrations and inventories were found to be highly variable, even in one species of the same peat bog and at the same time. Moreover, median Ti concentrations and inventories of different species and microhabitats were quite similar to one another. As a result, we suggest that more productive species might be able to accumulate more Ti onto their bigger surface areas than the less productive ones. Besides, Ti particles might be transported downwards with the water and accumulated by the mosses over a longer time period than only one year. To reliably specify the variations in the geochemistry of peat mosses on the peat bog surface the annual production of each collected Sphagnum sample has to be exactly known and samples of equal ages and time periods they were exposed to atmospheric deposition have to be studied. PMID:18166215

  13. Ferricrete, manganocrete, and bog iron occurrences with selected sedge bogs and active iron bogs and springs in the upper Animas River watershed, San Juan County, Colorado

    USGS Publications Warehouse

    Yager, Douglas B.; Church, Stanley E.; Verplanck, Philip L.; Wirt, Laurie

    2003-01-01

    During 1996 to 2000, the Bureau of Land Management, National Park Service, Environmental Protection Agency, United States Department of Agriculture (USDA) Forest Service, and the U.S. Geological Survey (USGS) developed a coordinated strategy to (1) study the environmental effects of historical mining on Federal lands, and (2) remediate contaminated sites that have the greatest impact on water quality and ecosystem health. This dataset provides information that contributes to these overall objectives and is part of the USGS Abandoned Mine Lands Initiative. Data presented here represent ferricrete occurrences and selected iron bogs and springs in the upper Animas River watershed in San Juan County near Silverton, Colorado. Ferricretes (stratified iron and manganese oxyhydroxide-cemented sedimentary deposits) are one indicator of the geochemical baseline conditions as well as the effect that weathering of mineralized rocks had on water quality in the Animas River watershed prior to mining. Logs and wood fragments preserved in several ferricretes in the upper Animas River watershed, collected primarily along streams, yield radiocarbon ages of modern to 9,580 years B.P. (P.L. Verplanck, D.B. Yager, and S.E. Church, work in progress). The presence of ferricrete deposits along the current stream courses indicates that climate and physiography of the Animas River watershed have been relatively constant throughout the Holocene and that weathering processes have been ongoing for thousands of years prior to historical mining activities. Thus, by knowing where ferricrete is preserved in the watershed today, land-management agencies have an indication of (1) where metal precipitation from weathering of altered rocks has occurred in the past, and (2) where this process is ongoing and may confound remediation efforts. These data are included as two coverages-a ferricrete coverage and a bogs and springs coverage. The coverages are included in ArcInfo shapefile and ArcInfo interchange file format.

  14. Elevated mercury accumulation in a peat bog of the Magellanic Moorlands, Chile (53°S) – an anthropogenic signal from the Southern Hemisphere

    Microsoft Academic Search

    H. Biester; R. Kilian; C. Franzen; C. Woda; A. Mangini; H. F. Schöler

    2002-01-01

    Increasing mercury deposition rates in the Northern Hemisphere recorded in natural archives such as peat bogs or lake sediments have been documented in numerous studies. However, data on atmospheric Hg deposition in the Southern Hemisphere dating back to pre-industrial times are rare. Here, we provide a continuous record of atmospheric Hg deposition in the Southern Hemisphere recorded by an ombrotrophic

  15. Kemp Research Report: The Buzz About Cranberry Bogs

    E-print Network

    Kemp Research Report: The Buzz About Cranberry Bogs A newsletter of the Kemp Natural Resources cranberry bogs. Research shows that bumblebee populations are in decline in numerous areas of the world. I in relationship to cranberry bogs? Well, it just so happens that the bumblebee (Bombus spp. Latreille) is the most

  16. Biogeochemistry and vegetation in a cranberry bog chronosequence Genevieve Noyce

    E-print Network

    Vallino, Joseph J.

    Biogeochemistry and vegetation in a cranberry bog chronosequence Genevieve Noyce Mount Holyoke Ecosystems Center, MBL, Woods Hole, MA 17 December 2007 #12;Noyce 2 Abstract Abandoned cranberry bogs abandoned bogs and two active ones, all in southeastern Massachusetts, to create a 70+ year chronosequence

  17. Spatial Patterns and Temporal Trajectories of the Bog Ground Layer

    E-print Network

    Benscoter, Brian W.

    Spatial Patterns and Temporal Trajectories of the Bog Ground Layer Along a Post-Fire Chronosequence in boreal bogs, wildfire selectively removes the ground layer vegetation, creating heterogeneous habitat along a chronosequence of post-fire bogs (1­105 years since fire) in north central Alberta, Canada. We

  18. Environmental controls of greenhouse gas release in a restoring peat bog in NW Germany

    NASA Astrophysics Data System (ADS)

    Glatzel, S.; Forbrich, I.; Krüger, C.; Lemke, S.; Gerold, G.

    2008-01-01

    In Central Europe, most bogs have a history of drainage and many of them are currently being restored. Success of restoration as well as greenhouse gas exchange of these bogs is influenced by environmental stress factors as drought and atmospheric nitrogen deposition. We determined the methane and nitrous oxide exchange of sites in the strongly decomposed center and less decomposed edge of the Pietzmoor bog in NW Germany in 2004. Also, we examined the methane and nitrous oxide exchange of mesocosms from the center and edge before, during, and following a drainage experiment as well as carbon dioxide release from disturbed unfertilized and nitrogen fertilized surface peat. In the field, methane fluxes ranged from 0 to 3.8 mg m-2 h-1 and were highest from hollows. Field nitrous oxide fluxes ranged from 0 to 574 ?g m-2 h-1 and were elevated at the edge. A large Eriophorum vaginatum tussock showed decreasing nitrous oxide release as the season progressed. Drainage of mesocosms decreased methane release to 0, even during rewetting. There was a tendency for a decrease of nitrous oxide release during drainage and for an increase in nitrous oxide release during rewetting. Nitrogen fertilization did not increase decomposition of surface peat. Our examinations suggest a competition between vascular vegetation and denitrifiers for excess nitrogen. We also provide evidence that the von Post humification index can be used to explain greenhouse gas release from bogs, if the role of vascular vegetation is also considered. An assessment of the greenhouse gas release from nitrogen saturated restoring bogs needs to take into account elevated release from fresh Sphagnum peat as well as from sedges growing on decomposed peat. Given the high atmospheric nitrogen deposition, restoration will not be able to achieve an oligotrophic ecosystem in the short term.

  19. Pre- and syn-ore zonation in Precambrian uraniferous sodic metasomatities

    SciTech Connect

    Omel'yanenko, B.I.; Mineyeva, I.G.

    1982-04-01

    Uraniferous-sodic metasomatites in Precambrian basement faults, in which a regular change in the mineral composition in vertical section has been established are described. The authors attempt to show that this pattern is controlled by the evolution of the solutions in time and space, and that it is an expression of a verticle metasomatic zonation. (JMT)

  20. Bog Hot Springs, Nevada: the geothermal cycle

    Microsoft Academic Search

    1977-01-01

    The Bog Hot Springs are located in one of the high desert valleys of northern Nevada below the Pueblo Mountains. The flow of the springs is estimated to be 2,500 gpm. Temperatures range from 125 to 212°F. (JGB)

  1. Spring photosynthesis in a cool temperate bog

    Microsoft Academic Search

    TIM R. M OORE; PETER M. L AFLEUR; IANE M. I. P OON; B ENJAMIN; W. H EUMANN

    2006-01-01

    In northern ecosystems, the onset and growth of spring photosynthesis may have an important influence on the annual carbon (C) budget, yet the controls have not been clearly identified, especially for peatlands. We used a 5-year set of daily carbon dioxide (CO2) exchange measurements derived from an eddy covariance tower located at Mer Bleue, an ombrotrophic bog near Ottawa, Canada,

  2. The Secret of Bog Creek Farm

    NSDL National Science Digital Library

    This fictional story about a real Superfund site is available in English or Spanish. The Secret of Bog Creek Farm is a story about a real Superfund site where children learn through the eyes of local residents. The story explains how soil can become polluted and how it can be cleaned up by incineration.

  3. Acidophilic Methanotrophic Communities from Sphagnum Peat Bogs

    Microsoft Academic Search

    SVETLANA N. DEDYSH; NICOLAI S. PANIKOV; JAMES M. TIEDJE

    1998-01-01

    Highly enriched methanotrophic communities (>25 serial transfers) were obtained from acidic ombrotro- phic peat bogs from four boreal forest sites. The enrichment strategy involved using media conditions that were associated with the highest rates of methane uptake by the original peat samples, namely, the use of diluted mineral medium of low buffering capacity, moderate incubation temperature (20°C), and pH values

  4. An ombrotrophic bog as a methane reservoir

    NASA Astrophysics Data System (ADS)

    Brown, Ann; Mathur, S. P.; Kushner, D. J.

    1989-09-01

    The distribution of methane in an ombrotrophic bog was examined by extracting the gas from different depths, using evacuated bottles and sampling tubes. Methane was extracted during 75 min, from 60 cm, 90 cm and 120 cm depths at 25 stations in a 24 meter-square area. The amount of methane extracted varied widely between samples, and this variation was greater within each depth than between the different depths. Approximately two and a half times as much methane was found at 90 cm and 120 cm depths as at 60 cm. The amount of methane from sites more than 60 cm below the surface can be correlated with the methane microbially produced from peat from the same site during laboratory incubations. Much less methane could be extracted from near-surface peat than from deeper levels, but laboratory incubations of peat from this level produced 10-fold more methane. Our results show that there is a considerable amount of methane trapped below 50 cm depth within an ombrotrophic bog, which we calculate in the bog studied to be 1.7 Gg. We suggest this entrapped methane reduces the hydraulic conductivity in the lower layers of the peat by blocking the soil pore spaces and preventing fluid movement; this in turn generates an elevated water table allowing the formation of a raised bog. We further suggest that if this peat is disturbed by mining or farming, the entrapped methane could be released into the atmosphere and add to the atmospheric pollution by greenhouse gases.

  5. Fate and Transport of Road Salt During Snowmelt Through a Calcareous Fen: Kampoosa Bog, Stockbridge, Massachusetts

    Microsoft Academic Search

    A. L. Rhodes; A. J. Guswa; A. Pufall

    2007-01-01

    Kampoosa Bog is the largest and most ecologically diverse calcareous lake-basin fen in Massachusetts. Situated within a 4.7 km2 drainage basin, the open fen (approx. 20 acres) consists of a floating mat of sedges (incl. Carex aquatilis and Cladium mariscoides) that overlie peat and lake clay deposits. Mineral weathering of marble bedrock within the drainage basin supplies highly alkaline ground

  6. Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia

    NASA Astrophysics Data System (ADS)

    Broder, T.; Blodau, C.; Biester, H.; Knorr, K. H.

    2012-04-01

    Ombrotrophic bogs in southern Patagonia have been examined with regard to paleoclimatic and geochemical research questions but knowledge about organic matter decomposition in these bogs is limited. Therefore, we examined peat humification with depth by Fourier Transformed Infrared (FTIR) measurements of solid peat, C/N ratio, and ?13C and ?15N isotope measurements in three bog sites. Peat decomposition generally increased with depth but distinct small scale variation occurred, reflecting fluctuations in factors controlling decomposition. C/N ratios varied mostly between 40 and 120 and were significantly correlated (R2 > 0.55, p < 0.01) with FTIR-derived humification indices. The degree of decomposition was lowest at a site presently dominated by Sphagnum mosses. The peat was most strongly decomposed at the driest site, where currently peat-forming vegetation produced less refractory organic material, possibly due to fertilizing effects of high sea spray deposition. Decomposition of peat was also advanced near ash layers, suggesting a stimulation of decomposition by ash deposition. Values of ?13C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while ?15N in the peat varied around zero and did not consistently relate to any decomposition index. Concentrations of DOM partly related to C/N ratios, partly to FTIR derived indices. They were not conclusively linked to the decomposition degree of the peat. DOM was enriched in 13C and in 15N relative to the solid phase probably due to multiple microbial modifications and recycling of N in these N-poor environments. In summary, the depth profiles of C/N ratios, ?13C values, and FTIR spectra seemed to reflect changes in environmental conditions affecting decomposition, such as bog wetness, but were dominated by site specific factors, and are further influenced by ash deposition and possibly by sea spray input.

  7. Comparison of Bacterial Communities in New England Sphagnum Bogs Using Terminal Restriction Fragment

    E-print Network

    Gotelli, Nicholas J.

    Microbial Ecology Comparison of Bacterial Communities in New England Sphagnum Bogs Using Terminal the taxonomic diversity of bacterial communities in wetlands, particularly Sphagnum bogs. To explore bacterial community composition, 24 bogs in Vermont and Massachusetts were censused for bacterial diversity

  8. Bog discharge from different viewpoints: comparison of Ingram's theory with observations from an Estonian raised bog

    NASA Astrophysics Data System (ADS)

    Oosterwoud, Marieke; van der Ploeg, Martine; van der Zee, Sjoerd

    2013-04-01

    Raised bogs are typically dome shaped and have a groundwater level located close to the soil surface. Besides their typical dome shape, these peatlands are often characterized by a pronounced surface topography consisting of pools, wet depressions (hollows), stretches of Sphagnum species (lawns), drier mounds (hummocks) and higher drier areas with terrestrial vegetation (ridges). These peat bodies drain laterally by gravity to adjacent areas with lower groundwater levels. The integrity of these bogs is only ascertained when water is stored in the peat body in periods of precipitation deficit and efficiently removed in wet periods. This is realized by the fact that the bog's top layer, often called acrotelm, has a variable hydraulic conductivity. In response to precipitation its hydraulic conductivity increases, whereas, under evaporative demand the water table lowers and therefore also the hydraulic conductivity decreases. Ingram proposed a model based on the Dupuit-Forchheimer approximation for Darcy's law that assumes vertical flow is negligible, and the slope of the water table is equal to the hydraulic gradient. U- Hm2- K = L2 (1) where U is net recharge (P-ET), K is horizontal hydraulic conductivity, Hm is hydraulic head above a flat bottom at the centre of the bog, L is half the width of the bog along the cross section. This model incorporates the assumption that all net rainfall reaching the water table will be discharged to the stream. Ingram's model does not consider local heterogeneities in surface topography, like pool-ridge patterns. We hypothesize that under drier conditions it is likely that pool-ridge patterning will inhibit water from flowing along the surface gradient. Under wet conditions, however, pools can become connected and water can move through the upper highly permeable layer of ridges. In this study, we investigated the influence of ridge-pool patterning on the horizontal water flow through a raised bog and compared it with Ingram's approach. Our study site was Mannikjarve, a raised bog located centrally in Estonia and part of the larger Endla Nature Reserve. The size of the bog is approximately 2 km2. Mannikjarve is characterized by a surface pattern of different microtopes consisting of ridge-pool, hollow-ridge, hummock-hollow, Sphagnum lawn, and margin forest. We created a flow-net based on the raised bogs surface elevation. This flow-net defines the direction of lateral flow in the acrotelm. Based on the flow-net we divided the bog into sub-catchments representing the area contributing to discharge at the outlets of the bog. The measured discharge was used in a double mass analysis to calculate discharge ratio's. We assume that changes in discharge ratio's can be relate to changes in contributing area as a result of variable water flow paths. Furthermore, we compared the measured discharges with calculated discharge according to Ingram's model. Based on several reasonable estimates for input parameters, the observed discharges cannot be reproduced with the Ingram model. Furthermore, discharge ratio's between different sub-catchments within the peatland appear to be not constant over time, thus suggesting a shift in water divides that depends on atmospheric events.

  9. Isotopic evidence for nitrogen mobility in peat bogs

    NASA Astrophysics Data System (ADS)

    Novak, Martin; Stepanova, Marketa; Jackova, Ivana; Vile, Melanie A.; Wieder, R. Kelman; Buzek, Frantisek; Adamova, Marie; Erbanova, Lucie; Fottova, Daniela; Komarek, Arnost

    2014-05-01

    Elevated nitrogen (N) input may reduce carbon (C) storage in peat. Under low atmospheric deposition, most N is bound in the moss layer. Under high N inputs, Sphagnum is not able to prevent penetration of dissolved N to deeper peat. Nitrogen may become available to the roots of invading vascular plants. The concurrent oxygenation of deeper peat layers, along with higher supply of labile organic C, may enhance microbial decomposition and lead to peat thinning. The resulting higher emissions of greenhouse gases may accelerate global warming. Seepage of N to deeper peat has never been quantified. Here we present evidence for post-depositional mobility of atmogenic N in peat, based on natural-abundance N isotope ratios. We conducted a reciprocal peat transplant experiment between two Sphagnum-dominated peat bogs in the Czech Republic (Central Europe), differing in anthropogenic N inputs. The northern site VJ received as much as 33 kg N ha-1 yr-1 via spruce canopy throughfall. The southern site was less polluted (17.6 kg N ha-1 yr-1). Isotope signatures of living moss differed between the two sites (?15N of -3‰ and -7‰ at VJ and CB, respectively). After 18 months, an isotope mass balance was constructed. In the CB-to-VJ transplant, a significant portion of original CB nitrogen (98-31%) was removed and replaced by nitrogen of the host site throughout the top 10 cm of the profile. Nitrogen, deposited at VJ, was immobilized in imported CB peat that was up to 20 years old. Additionally, we compared N concentration and N accumulation rates in 210Pb-dated peat profiles with well-constrained data on historical atmospheric N pollution. Nationwide N emissions peaked in 1990, while VJ exhibited the highest N content in peat that formed in 1930. This de-coupling of N inputs and N retention in peat might be interpreted as a result of translocation of dissolved pollutant N downcore, corroborating our ?15N results at VJ and CB. Data from a variety of peat bogs along pollution and climatic gradients would be needed to test to what extent the record of atmospheric N inputs in peat is overprinted by variable, locally-controlled decomposition rates.

  10. Origin of Lead in Eight Central European Peat Bogs Determined

    E-print Network

    Wieder, R. Kelman

    Research Origin of Lead in Eight Central European Peat Bogs Determined from Isotope Ratios was identified in 210Pb-dated profiles through eight peat bogs distributed over an area of 60 000 km2 with Germany, Austria, and Poland. Basal peat 14C-dated at 11 000 years BP had a relatively high 206Pb/207Pb

  11. 137Cs in a raised bog in central Sweden

    Microsoft Academic Search

    K. Rosén; M. Vinichuk; K. J. Johanson

    2009-01-01

    The vertical distribution of 137Cs activity in peat soil profiles and 137Cs activity concentration in plants of various species was studied in samples collected at two sites on a raised bog in central Sweden. One site (open bog) was in an area with no trees and only a few sparsely growing plant species, while the other (low pine) was less

  12. Bog breath: Sleeper factor in global warming?

    SciTech Connect

    Benyus, J.M.

    1995-04-01

    This artical examines the emission of gases from northern peatlands as plants grow and decay and its implication in the global increase in greenhouse gases, particularly carbon dioxide and methane. Bogs do extract carbon dioxide from the air, incorporating it into green plants which become buried for a long time. However, the cold, wet conditions are ideal for microbes which emit methane. Global climate change models indicate that Minnesota, for example will be 5 degrees warmer and somewhat wetter in future years. As a result bacterial metabolism and methane generation may increase considerably. This paper discusses current research and speculation and looks at possible solutions, both man-created and natural.

  13. Geoinformatics meets education for a peat bog information system

    NASA Astrophysics Data System (ADS)

    Michel, Ulrich; Fiene, Christina; Plass, Christian

    2010-10-01

    Within the project "Expedition Bog: Young researchers are experimenting, exploring and discovering" a bog-information- system is developed by the Department of Geography (University of Education Heidelberg, Germany), the Institute for Geoinformatics and Remote Sensing (University of Osnabrueck, Germany; the NABU Umweltpyramide gGmbH. This information system will be available for schools and to the public. It is supplemented by teaching units on various topics around the bog via an online platform. The focus of the project, however, is the original encounter with the bog habitat. This is realized by a GPS scavenger hunt with small research tasks and observations, mapping and experiments. The project areas are the Huvenhoops bog and the Lauenbruecker bog in Rotenburg in Lower Saxony, Germany. Equipped with a researcher backpack, GPS device and a mobile bog book by means of a pocket PC, students can discover different learning stations in the project bogs. In our areas the students can learn more about different topics such as "the historical memory of the bog", "water", "peat moss and other plants" and "animals of the bog". Moreover small inquiry research projects can be executed. Experimenting on site helps students to develop important scientific findings and increases their curiosity and enthusiasm for nature. It also promotes a number of other basic skills such as literacy, language skills, social skills or fine motor skills. Moreover it also fosters the development of a positive attitude to science in general. The main objective of the project is to promote sustainable environmental education, as well as the development of environmental awareness. This will be accomplished through the imparting of knowledge but also through experiencing nature with all senses in the context of original encounters.

  14. Smouldering bog wildfires and possible implications in palaeoenvironmental reconstructions

    NASA Astrophysics Data System (ADS)

    Zaccone, C.; Rein, G.; D'Orazio, V.; Hadden, R.; Belcher, C. M.; Miano, T. M.

    2012-04-01

    Ombrotrophic (i.e., rainwater-fed) peat bogs have been recognized as providing excellent records of past environmental changes over the last millennia. They are well known to provide information on both climatic and vegetational changes, and the deposition of organic and inorganic pollutants from anthropogenic vs. lithogenic sources. Whether they also record well past fire activity is an unresolved issue to date. Peatland ecosystems are most at risk from smouldering fires, especially in drought conditions. Smouldering fires are slow, low temperature, flameless and the most persistent form of combustion of organic matter (OM) in porous form. It is known to consume dozen of times more peat mass than flaming fires. Importantly, the in-depth oxidation reaction in smouldering leaves few charred remains, which hampers their identification in palaeoenvironmental analyses. Smouldering even consumes the possible pyrogenic char produced by flaming wildfires. Most studies on smouldering peatland fires to date have focused on ignition and carbon losses/emissions, leaving a significant gap in our understanding of OM changes following fires. In the present work, we present new data which suggest that variations in the chemical signature of OM in peatlands provides a possibility of identifying past peatland fires. In particular, we show results from a laboratory study about the physical, chemical and spectroscopic changes in OM features following a smouldering fire. We initiated a smouldering fire on top of three sphagnum peat columns (26 cm deep) each having a different initial moisture content (MC) designed to reflect dry conditions (55% MC), undisturbed conditions (90% MC), and wet conditions (210% MC). The fires were allowed to propagate downwards until they self-extinguished at some distance from the top. After the fire, we tracked chemical variations in the residual columns to determine the possible signature of natural past smouldering peatland fires. The analysis shows a consistent variation in the vertical direction of chemical markers below the point at which the fire front propagated the columns. The depth over which the chemical markers vary is apparent down to 5 cm in 55% MC (the whole residual column), and 8 cm deep in 90% MC. No significant variation of any of the chemical parameters was observed in the 210% MC column. The results of this study show that smouldering fires could occur also when bogs are in undisturbed hydrological conditions (e.g., near 100%MC), and that zone affected by smouldering fire is revealed by the presence of: 1) a strong increases of pH and ash content; 2) higher contents of aromatic and condensed molecules (as suggested by higher C/H values and by fluorescence spectra); 3) higher total N content leading to a decrease in C/N ratio. These data show potential to track similar variations in cores taken from peat bogs where they may serve as new proxies for the identification of past fire events. Moreover, these findings suggest the possibility that similar chemical and physical signatures detected in previous peatland cores may have been ascribed to the wrong past climatic or hydrological variations, as fire induced changes had not been considered before. In particular, peaks in ash content, such as those observed in our study (e.g.. ca. 13% in the 90% MC residue vs. 3% in the undisturbed peat), have in the past been ascribed to an increase of either dust depositions or mineralization processes typically linked to climatic changes. Similarly, large variations in pH values (e.g., >6 in the 90% MC residue vs.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  17. Detrimental effects of peat mining on amphibian abundance and species richness in bogs

    Microsoft Academic Search

    Marc J. Mazerolle

    2003-01-01

    Peat bogs of eastern North America are increasingly being mined for peat, which results in the extensive draining of these systems. First, I quantified the effects of peat mining on amphibian species richness and abundance in bog remnants adjacent to mining activity and unmined bogs. I then investigated amphibian occurrence patterns in bog remnants relative to the distance to the

  18. A multivariate analysis of the niches of plant populations in raised bogs. I. Niche dimensions

    E-print Network

    Johnson, Edward A.

    A multivariate analysis of the niches of plant populations in raised bogs. I. Niche dimensions E. A analysis of the niches of plant populations in raised bogs. I. Niche dimensions. Can. J. Bot. 55: 1201 populations in raised bogs. The two niche dimensions identified within the raised bogs are related to mineral

  19. Soil moisture, water tension, and water table relationships in a managed cutover bog

    Microsoft Academic Search

    Jonathan Price

    1997-01-01

    This study evaluates the hydrological conditions in a harvested bog where various water management schemes have been implemented to ameliorate conditions limiting Sphagnum regeneration. The study sites included a natural bog (natural), a recently drained and harvested bog (drained), which provided the hydrological extremes. Also included are a drained harvested bog with ditches blocked with (1) no other management (blocked),

  20. NORTHEASTERN NATURALIST2002 9(3):267284 ANT DIVERSITY IN PITCHER-PLANT BOGS

    E-print Network

    Gotelli, Nicholas J.

    NORTHEASTERN NATURALIST2002 9(3):267­284 ANT DIVERSITY IN PITCHER-PLANT BOGS OF MASSACHUSETTS AARON the first systematic inventory of ant species richness in pitcher-plant bogs of Massachusetts. Twenty-six species were collected in 18 bogs during 1999 and 2000. We collected the bog-specialist Myrmica lobifrons

  1. Algal flora of subalpine peat bog pools in the Krkonose Mts asy tn krkonosskch subalpnskch raselinis

    E-print Network

    Algal flora of subalpine peat bog pools in the Krkonose Mts asy tní krkonosských subalpínských, Czech Repub- lic, e-mail: sylnova@natur.cuni.cz Nováková S. (2002): Algal flora of subalpine peat bog raselinist peat bog and the Pancavské raselinist peat bog in the Krkonose Mts (Czech Republic) about 228 taxa

  2. Raised peat bog development and possible responses to environmental changes during the mid- to late-Holocene. Can the palaeoecological record be used to predict the nature and response of raised peat bogs to future climate change?

    Microsoft Academic Search

    Dmitri Mauquoy; Dan Yeloff

    2008-01-01

    Palaeoecological analyses of raised peat bog deposits in northwest Europe show the naturalness, antiquity and robust response\\u000a of these ecosystems to environmental changes from c. 7800 years ago to the present. A review of the techniques used to identify\\u000a these long-term features is presented and the role of climate change, autogenic change processes and human disturbance is\\u000a discussed. Millennial records of

  3. Radioactive waste disposal in simulated peat bog repositories

    SciTech Connect

    Schell, W.R.; Massey, C.D.

    1987-01-01

    The Low Level Radioactive Waste Policy Act of 1980 and the Low Level Radioactive Waste Policy Amendments Act of 1985 have required state governments to be responsible for providing low-level waste (LLW) disposal facilities in their respective areas. Questions are (a) is the technology sufficiently advanced to ensure that radioactive wastes can be stored for 300 to 1000 yr without entering into any uncontrolled area. (b) since actual experience does not exist for nuclear waste disposal over this time period, can the mathematical models developed be tested and verified using unequivocal data. (c) how can the public perception of the problem be addressed and the potential risk assessment of the hazards be communicated. To address the technical problems of nuclear waste disposal in the acid precipitation regions of the Northern Hemisphere, a project was initiated in 1984 to evaluate an alternative method of nuclear waste disposal that may not rely completely on engineered barriers to protect the public. Certain natural biogeochemical systems have been retaining deposited materials since the last Ice Age (12,000 to 15,000 yr). It is the authors belief that the biogeochemical system of wetlands and peat bogs may provide an example of an analogue for a nuclear waste repository system that can be tested and verified over a sufficient time period, at least for the LLW disposal problem.

  4. A hydrological study of Waen y Griafolen blanket bog, North Wales

    NASA Astrophysics Data System (ADS)

    Hall, G.

    2010-12-01

    Many mountain rivers in North Wales have their headwaters in peat blanket bogs. An example is Waen y Griafolen, source area for the Afon Mawddach, which formed the focus of a hydrological study by Bangor University over the period 2002-2004. Fieldwork has been supplemented by groundwater and surface water modelling. The blanket bog covers an area of approximately 6 km2 within a plateau basin in Lower Paleozoic shales. The structure of the blanket bog is complex. Erica and Trichophorum vegetation communities occupy the central area of the bog on deposits of old humified peat. Eroded into the old peat surface is a system of bifurcating channels occupied by actively accumulating Juncus and Sphagnum communities. River gravel and lake clay were found beneath the active peat channels at depths of several metres, indicative of an earlier and more extensive surface drainage system eroded into the bog surface. A palaeosoil occurs at the base of the old humified peat, with tree roots identified as Salix in growth position. A sample has been dated as 8905 ± 45 years before the reference year AD 1950. Waen y Griafolen has developed over the past 9000 years since the last ice sheets receded from upland Britain. Peat erosion represented by the buried river channels and lake bed may be linked to a period of increased rainfall across Europe at around 2600 years before the present. Groundwater levels have been continuously monitored at an instrumented borehole in the centre of the bog. It is found that the older humified peats have a surprisingly low water storage capacity and may become saturated during a single storm event. Storm flow occurs predominantly through fast surface runoff into the Juncus and Sphagnum infilled channels, where slow lateral movement takes place towards open stream courses at the basin outlet. There appears to be little vertical water movement into the underlying impermeable Ordovician shales. Climate change with an increase in winter rainfall may promote a reversion to fluvial erosion of the blanket bog. Modelling has been carried out with MODFLOW software to investigate the effects of replacing the Juncus and Sphagnum zones by gravel streams, as occurred in the 2600 b.p. erosion event. In an extreme case of complete removal of younger peat from channels, peak discharge from the basin would be almost doubled. This would have an adverse effect on flooding downstream. The Juncus / Sphagnum communities are seen as fragile. Management options to protect channel vegetation are recommended, including the blocking of surface streams to encourage a distributed water flow and maintain saturated ground conditions. References Hall G., 2008. An Integrated Meteorological /Hydrological Model for the Mawddach Catchment, North Wales. PhD Thesis, University of Wales, Bangor. Hall G. and Cratchley R., 2006. A hydrological study of Waen y Griafolen blanket bog, North Wales. Proc. International Conf. on Hydro-ecology. Carlsbad, Czech Republic

  5. Study of geochemical aspects of the peat bog genesis in eutrophic marshes in West Siberia by neutron activation analysis

    Microsoft Academic Search

    T. T. Efremova; S. P. Efremov; K. P. Koutzenogii; V. F. Peresedov

    1998-01-01

    Siberian peat bog are the largest in the world. Collecting of data on contaminating elements in Siberian peat deposits is\\u000a important because no quantitative information has been available till recently. As a rule, the distribution of the concentrations\\u000a of elements over the vertical profile of the stratigraphic column is used to study the evolution of pollutants in the environment.\\u000a Using

  6. Ecoenzymatic stoichiometry and microbial processing of organic matter in northern bogs and fens reveals a common P limitation among peatland types

    EPA Science Inventory

    We compared C, N, and P concentrations in atmospheric deposition, runoff, and soil standing stocks with microbial respiration (DHA) and ecoenzyme activity (EEA) in an ombrotrophic bog (S2) and a minerotrophic fen (S3) to investigate the environmental drivers of biogeochemical cyc...

  7. Fine-scale horizontal and vertical micro-distribution patterns of testate amoebae along a narrow fen/bog gradient

    E-print Network

    Paris-Sud XI, Université de

    fen/bog gradient Vincent E.J. Jassey1* , Geneviève Chiapusio1 , Edward A.D. Mitchell2 , Philippe Binet) and a young bog (bog) with9 more marked micro-topography and mosaic of poor-fen and bog vegetation. We) as well as the habitat (fen/bog) and the sampling depth.14 Testate amoeba Shannon H` diversity

  8. Methane flux dynamics in an Irish lowland blanket bog

    Microsoft Academic Search

    Anna Laine; David Wilson; Gerard Kiely; Kenneth A. Byrne

    2007-01-01

    Pristine peatlands are a significant source of atmospheric methane (CH4). Large spatio–temporal variation has been observed in flux rates within and between peatlands. Variation is commonly associated\\u000a with water level, vegetation structure, soil chemistry and climatic variability. We measured spatial and temporal variation\\u000a in CH4 fluxes in a blanket bog during the period 2003–2005. The surface of the bog was

  9. Stratigraphic controls on pool formation in a domed bog inferred from ground penetrating radar (GPR)

    NASA Astrophysics Data System (ADS)

    Comas, Xavier; Slater, Lee; Reeve, Andrew

    2005-12-01

    Ground penetrating radar (GPR) and terrain conductivity measurements reveal a close correlation between the location of water-filled pools and stratigraphic/lithologic features in Caribou Bog, a 2200-hectare peatland in central Maine. The geophysical profiles, supported by coring, define the general peatland stratigraphy as till underlain by glacio-marine sediment overlain by organic-rich lake sediment transitioning into terrestrial peat. GPR measurements show that open pools coincide with abrupt thinning of lake sediment and glaciomarine clay such that elevated mineral soil surfaces are in direct contact with the base of terrestrial peat. The width of these features, the GPR reflection patterns, the anomalously low terrain conductivity and the core samples obtained support the interpretation of these elevated mineral surfaces as the extension of buried eskers that outcrop on the periphery of Caribou bog. The geophysical results indicate that two parallel esker ridges are orientated N-S and dip towards the south. We suggest that the distribution of open pools is related to the distribution of depressions and beads associated with a beaded esker deposit, the pools possibly being maintained by local groundwater flow cells associated with the esker. GPR and EM31 surveys across Sphagnum pools (defined here as Sphagnum filled wet depressions) suggest a continuous sequence of underlying lake sediment and glacio-marine deposits devoid of elevated mineral surfaces. We suggest that Sphagnum pools developed after peatland formation (secondary features) due to changes in water table, peat accumulation and/or climatic controls.

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

    PubMed

    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. PMID:22221295

  11. 76 FR 77814 - Cameron LNG, LLC; Notice of Intent To Prepare an Environmental Assessment for the Proposed BOG...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ...Environmental Assessment for the Proposed BOG Liquefaction Project, and Request for Comments...discuss the environmental impacts of the BOG Liquefaction Project involving construction...facilities necessary to liquefy boil-off gas (BOG) at its existing liquefied natural...

  12. 77 FR 2970 - Notice of Intent To Prepare an Environmental Assessment for the Proposed Elba BOG Compressor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-20

    ...Environmental Assessment for the Proposed Elba BOG Compressor Project and Request for Comments...discuss the environmental impacts of the Elba BOG Compressor Project involving construction...and operate additional boil-off gas (BOG) compression facilities at its...

  13. Lithogenic, oceanic and anthropogenic sources of atmospheric Sb to a maritime blanket bog, Myrarnar, Faroe Islands.

    PubMed

    Shotyk, William; Chen, Bin; Krachler, Michael

    2005-12-01

    Antimony concentrations were measured in a core collected from Myrarnar, a blanket bog on the Faroe Islands which has been accumulating peat for more than six thousand years. The vertical distribution of Sb indicates that it has been supplied to the peat exclusively from the atmosphere. Despite the proximity to the ocean, the contribution of Sb to the peat from marine aerosols amounts to less than ca. 10% of the natural inputs. Although the peat core contains four notable layers of volcanic ash originating from Iceland, these have not contributed significantly to the Sb inventory. However, the distribution of Sb closely resembles that of Pb, with most of the Sb found in peats dating from the industrial period. Peat samples dating from the Roman Period are not only contaminated with Pb, but also with Sb. Lead is known to be immobile in peat bogs, and in Europe has been derived predominantly from industrial sources for thousands of years. The correlation between Sb and Pb in the peat core from the Faroe Islands supports the hypothesis that Sb is also effectively immobile in peat, and that ombrotrophic bogs are faithful archives of atmospheric Sb deposition. The data presented here also reinforces the view that natural Sb inputs during the past two centuries are dwarfed by industrial inputs, and that human activities have affected the atmospheric Sb cycle to a comparable extent to that of Pb. The natural rate of atmospheric Sb deposition recorded by the peat core (0.33 microg m(-2) year(-1)) is remarkably similar to the value obtained from a Swiss peat bog (Etang de la Gruère) in the samples dating from ca. 6000 to 9000 years ago (0.35 microg m(-2) year(-1)) which suggests that the background rates obtained from the peat cores have broader validity. Consistent with previous work, the data from the Faroe Islands suggests that the natural flux of Sb to the global atmosphere may have been overestimated by a factor of ten, and that the influence of human activities has been underestimated to the same extent. PMID:16307065

  14. Soil data for a collapse-scar bog chronosequence in Koyukuk Flats National Wildlife Refuge, Alaska, 2008

    USGS Publications Warehouse

    O’Donnell, Jonathan A.; Harden, Jennifer W.; Manies, Kristen L.; Jorgenson, M. Torre

    2012-01-01

    Peatlands in the northern permafrost region store large amounts of organic carbon, most of which is currently stored in frozen peat deposits. Recent warming at high-latitudes has accelerated permafrost thaw in peatlands, which will likely result in the loss of soil organic carbon from previously frozen peat deposits to the atmosphere. Here, we report soil organic carbon inventories, soil physical data, and field descriptions from a collapse-scar bog chronosequence located in a peatland ecosystem at Koyukuk Flats National Wildlife Refuge in Alaska.

  15. Biogeochemistry of carbon and related major and trace elements in peat bog soils of the middle taiga of Western Siberia (Russia).

    NASA Astrophysics Data System (ADS)

    Stepanova, V. A.; Mironycheva-Tokareva, N. P.; Pokrovsky, O. S.

    2012-04-01

    Global climate changes impact the status of wetland ecosystems shifting the balances of the carbon, macro-, and microelements cycles. This study aims to establish the features of accumulation and distribution of major- and trace elements in the organic layer of peat bog soils, belonging to different ecosystems of the oligotrophic bog complex located in the middle taiga of Western Siberia (Khanty-Mansiysk region, Russia). Key areas which are selected for this study include the following bog conjugate elementary ecosystems: higher ryam, lower ryam, ridge-hollow complex, and oligotrophic poor fen as characterized previously [1]. We have sampled various peat types along the entire length of the soil column (every 10 cm down to 3 m). Peat samples were analyzed for a wide range of macro- and microelements using an ICP-MS technique following full acid digestion in a microwave oven. These measurements allowed quantitative estimates of major- and trace elements in the peat deposits within the whole bog complex and individual elementary landscapes. Based on the data obtained, the lateral and radial geochemical structures of the bog landscapes were determined and clarified for the first time for middle taiga of the West Siberian plain. The similar regime of mineral nutrition during the complete bog landscape formation was detected for the peat deposits based on the measurements of some major- and trace elements (Ca, Fe, Mg, etc.). The vertical distribution of some major and some trace elements along the profile of peat column is rather uniform with relatively strong increase in the bottom organic layers. This strongly suggests the similarity of the processes of element accumulation in the peat and relatively weak post depositional redistribution of elements within the peat soil profile. Overall, obtained corroborate the existing view on chemical composition of peats being determined by botanical peat's components (which forms this peat deposit), atmospheric precipitation, position of ecosystems in the landscape (lateral migration) and types of bedrocks [2]. The results allow better understanding of the coupling between biogeochemical cycles of carbon and major and trace elements in peat soils in order to predict the future changes in both concentrations and stocks of chemical elements in the Western Siberia peat bog systems under climate warming.

  16. Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia

    NASA Astrophysics Data System (ADS)

    Broder, T.; Blodau, C.; Biester, H.; Knorr, K. H.

    2011-10-01

    Ombrotrophic bogs in southern Patagonia have been examined with regard to paleoclimatic and geochemical research questions but knowledge about organic matter decomposition in these bogs is limited. Therefore, we examined peat humification with depth by Fourier Transformed Infrared (FTIR) measurements of solid peat, C/N ratio, and ?13C and ?15N isotope measurements in three bog sites. Peat decomposition generally increased with depth but distinct small scale variation probably caused by environmental changes occurred. C/N ratios varied mostly between 40 and 120 and were significantly correlated (R2 > 0.55, p < 0.01) with FTIR-derived humification indices. The degree of decomposition was lowest at the site with the least sea spray input, while the peat was most decomposed at the driest site with highest sea spray deposition. Decomposition of peat was also advanced near ash layers. Values of ?13C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while ?15N in the peat varied around zero and did not consistently relate to any decomposition index. Concentrations of DOM partly related to C/N ratios, partly to FTIR derived indices. DOM was enriched in 13C and in 15N relative to the solid phase probably due to multiple microbial modifications and recycling of N in these N-poor environments. In summary, paleoclimatic signals may have influenced decomposition according to depth profiles of C/N ratios, ?13C values, and FTIR spectra, but the study also suggests that decomposition was also influenced by ash layers, sea spray input and other site specific factors.

  17. Vegetation feedbacks of nutrient addition lead to a weaker carbon sink in an ombrotrophic bog.

    PubMed

    Larmola, Tuula; Bubier, Jill L; Kobyljanec, Christine; Basiliko, Nathan; Juutinen, Sari; Humphreys, Elyn; Preston, Michael; Moore, Tim R

    2013-12-01

    To study vegetation feedbacks of nutrient addition on carbon sequestration capacity, we investigated vegetation and ecosystem CO2 exchange at Mer Bleue Bog, Canada in plots that had been fertilized with nitrogen (N) or with N plus phosphorus (P) and potassium (K) for 7-12 years. Gross photosynthesis, ecosystem respiration, and net CO2 exchange were measured weekly during May-September 2011 using climate-controlled chambers. A substrate-induced respiration technique was used to determine the functional ability of the microbial community. The highest N and NPK additions were associated with 40% less net CO2 uptake than the control. In the NPK additions, a diminished C sink potential was due to a 20-30% increase in ecosystem respiration, while gross photosynthesis rates did not change as greater vascular plant biomass compensated for the decrease in Sphagnum mosses. In the highest N-only treatment, small reductions in gross photosynthesis and no change in ecosystem respiration led to the reduced C sink. Substrate-induced microbial respiration was significantly higher in all levels of NPK additions compared with control. The temperature sensitivity of respiration in the plots was lower with increasing cumulative N load, suggesting more labile sources of respired CO2 . The weaker C sink potential could be explained by changes in nutrient availability, higher woody : foliar ratio, moss loss, and enhanced decomposition. Stronger responses to NPK fertilization than to N-only fertilization for both shrub biomass production and decomposition suggest that the bog ecosystem is N-P/K colimited rather than N-limited. Negative effects of further N-only deposition were indicated by delayed spring CO2 uptake. In contrast to forests, increased wood formation and surface litter accumulation in bogs seem to reduce the C sink potential owing to the loss of peat-forming Sphagnum. PMID:23868415

  18. New geological model of the Lagoa Real uraniferous albitites from Bahia (Brazil)

    NASA Astrophysics Data System (ADS)

    Oliveira Chaves, Alexandre

    2013-09-01

    New evidence supported by petrography (including mineral chemistry), lithogeochemistry, U-Pb geochronology by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), and physicochemical study of fluid and melt inclusions by LA-ICP-MS and microthermometry, point to an orogenic setting of Lagoa Real (Bahia-Brazil) involving uraniferous mineralization. Unlike the previous models in which uraniferous albitites represent Na-metasomatised 1.75 Ga anorogenic granitic rocks, it is understood here that they correspond to metamorphosed sodium-rich and quartz-free 1.9 Ga late-orogenic syenitic rocks (Na-metasyenites). These syenitic rocks are rich not only in albite, but also in U-rich titanite (source of uranium). The interpretation of geochemical data points to a petrogenetic connection between alkali-diorite (local amphibolite protolith) and sodic syenite by fractional crystallization through a transalkaline series. This magmatic differentiation occurred either before or during shear processes, which in turn led to albitite and amphibolite formation. The metamorphic reactions, which include intense recrystallization of magmatic minerals, led uraninite to precipitate at 1.87 Ga under Oxidation/Reduction control. A second population of uraninites was also generated by the reactivation of shear zones during the 0.6 Ga Brasiliano Orogeny. The geotectonic implications include the importance of the Orosirian event in the Paramirim Block during paleoproterozoic S?o Francisco Craton edification and the influence of the Brasiliano event in the Paramirim Block during the West-Gondwana assembly processes. The regional microcline-gneiss, whose protolith is a 2.0 Ga syn-collisional potassic granite, represents the albitite host rock. The microcilne-gneiss has no petrogenetic association to the syenite (albitite protolith) in magmatic evolutionary terms.

  19. Acidophilic Methanotrophic Communities from Sphagnum Peat Bogs

    PubMed Central

    Dedysh, Svetlana N.; Panikov, Nicolai S.; Tiedje, James M.

    1998-01-01

    Highly enriched methanotrophic communities (>25 serial transfers) were obtained from acidic ombrotrophic peat bogs from four boreal forest sites. The enrichment strategy involved using media conditions that were associated with the highest rates of methane uptake by the original peat samples, namely, the use of diluted mineral medium of low buffering capacity, moderate incubation temperature (20°C), and pH values of 3 to 6. Enriched communities contained a mixture of rod-shaped bacteria arranged in aggregates with a minor contribution of Hyphomicrobium-like cells. The growth stoichiometry of isolates was characteristic of methanotrophic bacteria (CH4/O2/CO2=1:1.1:0.59), with an average apparent yield of 0.41 ± 0.03 g of biomass C/g of CH4-C. DNA from each enrichment yielded a PCR product of the expected size with primers for both mmoX and mmoY genes of soluble methane monooxygenase. Two types of sequences were obtained for PCR-amplified fragments of mmoX. One of them exhibited high identity to the mmoX protein of the Methylocystis-Methylosinus group, whereas the other showed an equal level of divergence from both the Methylosinus-Methylocystis group and Methylococcus capsulatus (Bath) and formed a distinct branch. The pH optimum for growth and for CH4 uptake was 4.5 to 5.5, which is very similar to that for the optimum CH4 uptake observed in the original peat samples. These methanotrophs are moderate acidophiles rather than acidotolerant organisms, since their growth rate and methane uptake were much lower at neutral pH. The growth of the methanotrophic community was enhanced by using media with a very low salt content (20 to 200 mg/liter), more typical of their natural environment. All four enriched communities grew on N-free medium. PMID:9501432

  20. Plant biomass and production and CO2 exchange in an ombrotrophic bog

    Microsoft Academic Search

    Tim R. Moore; Jill L. Bubier; Steve E. Frolking; Peter M. Lafleur; Nigel T. Roulet

    2002-01-01

    Summary 1 Above-ground biomass was measured at bog hummock, bog hollow and poor-fen sites in Mer Bleue, a large, raised ombrotrophic bog near Ottawa, Ont., Canada. The average above-ground biomass was 587 g m -2 in the bog, composed mainly of shrubs and Sphagnum capitula. In the poor fen, the average biomass was 317 g m -2 , comprising mainly

  1. The Bogs of Central Minnesota Author(s): Verona M. Conway

    E-print Network

    Minnesota, University of

    The Bogs of Central Minnesota Author(s): Verona M. Conway Reviewed work(s): Source: Ecological and extend access to Ecological Monographs. http://www.jstor.org #12;THE BOGS OF CENTRAL MINNESOTA VERONA M OF WORK .7...................... 176 OUTLINE OF THE BOG SUCCESSION; THE DEVELOPMENT OF ACIDITY .177

  2. Seasonal contribution of CO2 fluxes in the annual C budget of a northern bog

    E-print Network

    Roulet, Nigel T.

    Seasonal contribution of CO2 fluxes in the annual C budget of a northern bog Charlotte L. Roehm of carbon exchange with seasons in a bog located in the cool temperate climate region. The growing season CO contribution of CO2 fluxes in the annual C budget of a northern bog, Global Biogeochem. Cycles, 17(1), 1029

  3. Page 1 of 28 Budget Options Group (BOG) Options Summary & Analysis

    E-print Network

    Ickert-Bond, Steffi

    Page 1 of 28 Budget Options Group (BOG) ­ Options Summary & Analysis February 26, 2014 The Budget Options Group (BOG), appointed by Chancellor Brian Rogers and convened in January 2014, was charged in the sense that it is expected to change as ideas are vetted and new options are developed. The BOG

  4. Plant community structure and soil properties along stream corridors of cranberry bogs since discontinuation of agriculture.

    E-print Network

    Vallino, Joseph J.

    Plant community structure and soil properties along stream corridors of cranberry bogs since Laboratory 7 MBL Street Woods Hole, Massachusetts 02543 #12;Poole 1 Abstract Many cranberry bogs in Cape Cod area along the sides of rivers which run through cranberry bogs. The main site of my study was along

  5. Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog

    E-print Network

    Roulet, Nigel T.

    Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog bog near Ottawa, Canada from 1 June 1998 to 31 May 2002. Temperatures during this period were above season. During the first 3 years of study, the bog was an annual sink for CO2 ($À260 g CO2 mÀ2 yrÀ1

  6. Movements, Habitat Use, and Thermal Ecology of an Isolated Population of Bog Turtles (Glyptemys muhlenbergii)

    E-print Network

    Dorcas, Michael E.

    Movements, Habitat Use, and Thermal Ecology of an Isolated Population of Bog Turtles (Glyptemys to anthropogenic habitat modification. The federally threatened Bog Turtle (Glyptemys muhlenbergii) requires specialized wetland habitats, such as bogs and fens, in the eastern United States and often occurs in isolated

  7. Holocene peatland development and hydrological variability inferred from bog-pine dendrochronology

    E-print Network

    Stoffel, Markus

    Holocene peatland development and hydrological variability inferred from bog-pine dendrochronology-dating with German bog-pine chronologies, whereas two short additional records of older ages were radiocarbon dated fluctuations in bog-surface wetness. A major establishment phase at 7200­6900 cal a BP reflects the onset

  8. The University of Notre Dame The Developmental History of Cedar Creek Bog, Minnesota

    E-print Network

    Minnesota, University of

    The University of Notre Dame The Developmental History of Cedar Creek Bog, Minnesota Author Midland Naturalist. http://www.jstor.org #12;The Developmental History of Cedar Creek Bog, Minnesota* Raymond L. Lindeman The Anoka Sand Plain of east centralMinnesota is liberallysprinkledwith lakes, bogs

  9. Florida BOG Policy Guideline # PG 05.02.15 Academic Learning Compacts

    E-print Network

    Kaup, David J.

    Florida BOG Policy Guideline # PG 05.02.15 Academic Learning Compacts Policy / Purpose, Sec. 7, Florida Constitution BOG Resolutions: · Academic Learning Compacts for baccalaureate degree-0467 State University System / Division of Colleges & Universities BOG ALC Policy Guideline.doc 1 #12;Florida

  10. Development of south Swedish pine chronologies from peat bogs extension of existing records and assessment of

    E-print Network

    Stoffel, Markus

    Development of south Swedish pine chronologies from peat bogs ­ extension of existing records. Periods of relatively warm and dry climatic conditions sometimes allow pine establishment on peat bogs influence growth rates of peatland pines, trees growing on bogs in southern Sweden are more sensitive

  11. An Investigation of mid to late Holocene fossil insects from raised bogs

    E-print Network

    Sheldon, Nathan D.

    1 An Investigation of mid to late Holocene fossil insects from raised bogs in the Irish Midlands the results of late Holocene insect fossil analysis from six raised bogs in the Irish Midlands. A distribution) to the dome (centre) of Ballykean Bog, County Offaly, Ireland. The purpose of this study was to detect any

  12. Small-scale spatial variation of benthic algal assemblages in a peat bog Katerina Cerna n

    E-print Network

    Small-scale spatial variation of benthic algal assemblages in a peat bog Katerina Cerna´ n test Peat bog a b s t r a c t Spatial patterns on a very small scale (10 cm), and the effect microhabitat types were investigated. Samples were taken in a peat bog along linear transects on a scale of 10

  13. Epigeic spiders as ecological indicators of conservation value for peat bogs

    Microsoft Academic Search

    Alan G. Scott; Geoff S. Oxford; Paul A. Selden

    2006-01-01

    Raised and basin bogs are in serious decline throughout the western Palaearctic. There is a need for a monitoring protocol that would signal changes in the habitat and the biota it supports. Spiders (Araneae) are a group of predators containing many bog specialist species, some of which are of Red Data Book status. Twelve-month continuous trapping in 11 basin bogs

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

    NASA Astrophysics Data System (ADS)

    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 ?m) 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

  15. Floral composition of a sphagnum bog in Robertson county, Texas 

    E-print Network

    Rowell, Chester Morrison, Jr

    1949-01-01

    M ~11 P Crcwd'oot, Hoist places of zone I and lower end of zone II, Spring. Occasional to frequent in isolated areas ~ Fumariaceae ~C. d 1' i'I'lid. Golden Corydalis Moods& open sand. Early spring. Occasional, ur uvL. srae lap d' ~ L..., The highway distance between College Station and the bog is anproximataly fit'ty- five miles. There is at least one other bog in Robertson county . It was first shown to the author in the spring of 19/7 by Dr. Fred A. Barkley during a collection trip...

  16. Effects of climatic change on chemistry and vegetation of peatlands, with special reference to interaction with atmospheric deposition

    Microsoft Academic Search

    H. Dam; B. Beltman

    1992-01-01

    This paper summarizes expected changes in hydrology, chemistry and biota of Dutch peatlands (bogs, fens and moorland pools) caused by climatic changes resulting from the Greenhouse Effect. Special attention is paid to the interaction with atmospheric acid deposition. In both bogs and moorland pools prolonged drought periods may cause deleterious effects on biota because of the release of atmospherically-derived reduced

  17. GHG emissions from temperate lowland bog under contrasting land use: insights from the Defra Lowland Bog Project.

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; dIXON, Simon

    2015-04-01

    The Defra lowland peat project was established 3 years ago in response to the estimation that while lowland peat soils represent only 15% of the area of UK peat they represented 75% of the greenhouse gas emissions. The study has considered a range of settings, including: restored raised bog; extracted bare peat; and peat soil converted for arable. The sites were instrumented to cover as complete a range of greenhouse gases as possible and this included N2O as well as fluvial carbon fluxes. This talk will review results with particular emphasis on problems of understanding fluvial carbon fluxes from lowland raised bogs where flow directions are complex.

  18. Hydrogeological analysis of factors that influence pitcher plant bog viability at the Joseph Pine Preserve,Sussex, Virginia

    E-print Network

    Darby, Dennis

    Hydrogeological analysis of factors that influence pitcher plant bog viability at the Joseph Pine hydrological regime that support rare pitcher plant bog habitats. STRATIGRAPHY Nutrient-poor saturated bogs. Bogs supporting yellow pitcher plants historically occurred in eight counties in Virginia but surveys

  19. BOGS AND FENS IN THE HUDSON BAY LOWLANDS

    Microsoft Academic Search

    Hugo Sjors

    ty of metal ions in water of precipitation (except in definitely maritime areas) leads to strongly acid reactions both of the water and of the peat in most ombrotrophic peatlands. The vegetation of the ombrotrophic peat- lands, or (in a restricted sense) bogs, is highly specialized, acidophilous, and poor in species of flowering plants. Other types of peatland receive varying

  20. Methane emissions from fen, bog and swamp peatlands in Quebec

    Microsoft Academic Search

    T. R. Moore; R. Knowles

    1990-01-01

    A static chamber technique was used weekly from spring thaw to winter freezing to measure methane emissions from 10 sites representing subarctic fens and temperate swamps and bogs. Rates of 4 m-2 d-1 were recorded in subarctic fens: within-site emissions were primarily controlled by the evolution of the peat thermal regime, though significant releases during spring thaw were recorded at

  1. SURFACE AND GROUNDWATER MODELING OF BOG TURTLE HABITATS

    Microsoft Academic Search

    Jeremy D. Colello; Kelly E. Brennan

    2 ABSTRACT: Protecting the natural environment while fostering local development is one of the main challenges that engineers face today. New species are added to the federally threatened and endangered species list as their habitats are destroyed by residential and commercial development. The bog turtle (clemmys muhlenbergii) is threatened by new development that damages not only its wetland habitat, but

  2. Ecosystem Respiration in a Cool Temperate Bog Depends on Peat

    E-print Network

    Roulet, Nigel T.

    Ecosystem Respiration in a Cool Temperate Bog Depends on Peat Temperature But Not Water Table P-summer (July-August). As anticipated, there was a strong relationship between ER and peat temperatures (r2 = 0-table depth (r2 = 0.11). A laboratory incubation of peat cores at different moisture contents showed that CO2

  3. Modelling alternative states of an ombrotrophic bog with experimentally deposed nitrogen

    NASA Astrophysics Data System (ADS)

    Wu, Yuanqiao; Keller, Philipp; Blodau, Christian

    2015-04-01

    Nitrogen (N) pollution of peatlands alters their vegetation composition and carbon (C) sequestration. We applied a coupled carbon and nitrogen wetland model (PEATBOG) to analyse alternative steady states of an ombrotrophic bog exposed to experimentally deposited N at 1.6, 3.2 and 6.4 gN m-2 yr-1. The study predicted discontinuous responses of the peatland ecosystem to differing N deposition and a lack of recovery after 15 years of fertilization with 6.4 gN m-2 yr-1, which indicated a regime shift of the modelled ecosystem. In combination drought, as concurrent disturbance, reduced the resilience of the system and contributed to the regime shift. Internal feedbacks may interact with the direct feedback of the external disturbances from nitrogen and climatic drivers and alter the responses of the ecosystem. The result suggested that the state of a peatland exposed to N deposition may be highly uncertain due to a dominant feedback loop that emerged from all disturbances. The finding highlighted the need for systematically quantifying the relative importance of multiple disturbances to predict the potential shift of a peatland ecosystem to alternative states as response to N deposition in a changing environment.

  4. Mineralogy and geochemistry of a uraniferous coal from the Red Desert Area, Sweetwater County, Wyoming

    USGS Publications Warehouse

    Breger, Irving A.; Deul, Maurice; Meyrowitz, Robert; Rubinstein, Samuel

    1953-01-01

    A sample of subbituminous uraniferous coal from the Red Desert, Sweetwater County, Wyo., was studied mineralogically. The coal contains gypsum (6 percent), kaolinite (1 percent), quartz (0.3 percent), calcite (trace), and limonite (trace). This suite of minerals and the absence of pyrite show that the coal has been subjected to weathering and oxidation. No uranium minerals have been found; mechanical fractionation has indicated that the uranium is associated with the organic constituents of the coal. The minerals that have been isolated contain 0.0006 percent uranium, a content which is to be expected for nonuraniferous sedimentary rocks. The organic components of the coal contain approximately 0.002 percent uranium. On the basis of material balance calculations, the organic components carry 98 percent of the uranium in the coal. Fischer assays of this weathered coal from the Red Desert indicate a yield of 16.7 gallons of tar per ton on low-temperature retorting. In view of the large reserve of subbituminous coal in the Red Desert, its probable ease of mining, and its tar yield, it may be desirable to carry out further evaluation of the coal as a fuel or raw material for the manufacture of tar or chemicals. If economic factors permit utilization of the coal, the uranium, although present in small percentages, could be recovered as a byproduct.

  5. Algal community patterns in Slovenian bogs along environmental gradients

    Microsoft Academic Search

    Aleksandra Krivograd Klemen?i?; Nataša Smolar-Žvanut; Darja Isteni?; Tjaša Griessler-Bulc

    2010-01-01

    In 2005 and 2006, epiphyton samples were collected from seven lowland and montane peat bogs in Slovenia. Water temperature,\\u000a pH, conductivity, dissolved oxygen and saturation were measured at the same time. Diatoms, desmids and Cyanobacteria were\\u000a the most abundand groups in species number. Canonical Correspondence Analysis (CCA) was carried out on Cyanobacteria, diatom\\u000a and desmid flora composition. This analysis showed

  6. Does nitrogen addition to raised bogs influence peat phosphorus pools?

    Microsoft Academic Search

    B. L. Williams; D. J. Silcock

    2001-01-01

    Two Sphagnum moss species occupying hummock areas (Sphagnum capillifolium) and wetter hollows (Sphagnum recurvum) on a raised bog in north east Scotland were treated every two weeks with NH4NO3 solutions to supply 3g N m-2 yr-1. Although S. recurvum moss contained a greater concentration of total P than S. capillifolium the amounts and N:P ratios were similar in both species.

  7. The Auchenorrhyncha fauna of peat bogs in the Austrian part of the Bohemian Forest (Insecta, Hemiptera)

    PubMed Central

    Holzinger, Werner E.; Schlosser, Lydia

    2013-01-01

    Abstract The first overview on the Auchenorrhyncha fauna of peat bogs of the Austrian Bohemian Forest is presented. Seven oligotrophic peat bog sites were studied in 2011 by suction sampler (“G-Vac”) and 93 Auchenorrhyncha species (with 7465 adult specimens) were recorded. Eleven species (about 18 % of the individuals) are tyrphobiontic or tyrphophilous. The relative species abundance plot is not very steep; the six most abundant species represent 50 % of the individuals. The most common species is Conomelus anceps (17 % of the individuals). Compared to the whole Austrian Auchenorrhyncha fauna, the fauna of peat bogs comprises distinctly more univoltine species and more species hibernating in nymphal stage. Densities of adult Auchenorrhyncha in peat bogs are low in spring (about 10–60 individuals per m²) and high in July, with up to 180 (±50) individuals per m². Disturbed peat bogs have higher species numbers and higher Auchenorrhyncha densities in total, but lower numbers and densities in peat bog specialists. PMID:24039517

  8. Environmental assessment of remedial action at the inactive uraniferous lignite processing sites at Belfield and Bowman, North Dakota. [UMTRA Project

    SciTech Connect

    Beranich, S.; Berger, N.; Bierley, D.; Bond, T.M.; Burt, C.; Caldwell, J.A.; Dery, V.A.; Dutcher, A.; Glover, W.A.; Heydenburg, R.J.; Larson, N.B.; Lindsey, G.; Longley, J.M.; Millard, J.B.; Miller, M.; Peel, R.C.; Persson-Reeves, C.H.; Titus, F.B.; Wagner, L.

    1989-09-01

    The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), to clean up the Belfield and Bowman, North Dakota, uraniferous lignite processing sites to reduce the potential health impacts associated with the residual radioactive materials remaining at these sites. Remedial action at these sites must be performed in accordance with the US Environmental Protection Agency's (EPA) standards promulgated for the remedial action and with the concurrence of the US Nuclear Regulatory Commission (NRC) and the state of North Dakota. The inactive Belfield uraniferous lignite processing site is one mile southeast of Belfield, North Dakota. The inactive Bowman uraniferous lignite processing site at the former town of Griffin, is seven miles northwest of Bowman, North Dakota and 65 road miles south of Belfield. Lignite ash from the processing operations has contaminated the soils over the entire 10.7-acre designated Belfield site and the entire 12.1-acre designated Bowman site. Dispersion of the ash has contaminated an additional 20.6 acres surrounding the Belfield processing site and an additional 59.2 acres surrounding the Bowman processing site. The proposed remedial action is to relocate the contaminated materials at the Belfield processing site to the Bowman processing/disposal site for codisposal with the Bowman contaminated soils. The environmental impacts assessed in this EA were evaluated for the proposed remedial action and the no action alternative and demonstrate that the proposed action would not significantly affect the quality of the human environment and would be performed in compliance with applicable environmental laws. The no action alternative would not be consistent with the intent of Public Law 95-604 and would not comply with the EPA standards. 48 refs., 10 figs., 7 tabs.

  9. Towards a conceptual model of hydrological change on an abandoned cutover bog, Quebec

    Microsoft Academic Search

    Tim E. Van Seters; Jonathan S. Price

    2002-01-01

    Cutover bogs do not return to functional peatland ecosystems after abandonment because re-establishment of peat- forming mosses is poor. This paper presents a conceptual model of bog disturbance caused by peat harvesting (1942-1972), and the hydrological evolution that occurred after abandonment (1973-1998). Two adjacent bogs of similar size and origin, one harvested and the other essentially undisturbed, provide the basis

  10. Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

    USGS Publications Warehouse

    Mazerolle, M.J.; Poulin, M.; Lavoie, C.; Rochefort, L.; Desrochers, A.; Drolet, B.

    2006-01-01

    1. Peatlands have suffered great losses following drainage for agriculture, forestry, urbanisation, or peat mining, near inhabited areas. We evaluated the faunal and vegetation patterns after restoration of a peatland formerly mined for peat. We assessed whether bog pools created during restoration are similar to natural bog pools in terms of water chemistry, vegetation structure and composition, as well as amphibian and arthropod occurrence patterns. 2. Both avian species richness and peatland vegetation cover at the site increased following restoration. Within bog pools, however, the vegetation composition differed between natural and man-made pools. The cover of low shrubs, Sphagnum moss, submerged, emergent and floating vegetation in man-made pools was lower than in natural pools, whereas pH was higher than in typical bog pools. Dominant plant species also differed between man-made and natural pools. 3. Amphibian tadpoles, juveniles and adults occurred more often in man-made pools than natural bog pools. Although some arthropods, including Coleoptera bog specialists, readily colonised the pools, their abundance was two to 26 times lower than in natural bog pools. Plant introduction in bog pools, at the stocking densities we applied, had no effect on the occurrence of most groups. 4. We conclude that our restoration efforts were partially successful. Peatland-wide vegetation patterns following restoration mimicked those of natural peatlands, but 4 years were not sufficient for man-made pools to fully emulate the characteristics of natural bog pools.

  11. Microbial communities and transformation of carbon compounds in bog soils of the taiga zone (Tomsk oblast)

    NASA Astrophysics Data System (ADS)

    Grodnitskaya, I. D.; Trusova, M. Yu.

    2009-09-01

    Two types of bogs were studied in Tomsk oblast—Maloe Zhukovskoe (an eutrophic peat low-moor bog) and Ozernoe (an oligotrophic peat high-moor bog). The gram-negative forms of Proteobacteria were found to be dominant and amounted to more than 40% of the total population of the microorganisms investigated. In the peat bogs, the population and diversity of the hydrolytic microbial complex, especially of the number of micromycetes, were lower than those in the mineral soils. The changes in the quantitative indices of the total microbiological activity of the bogs were established. The microbial biomass and the intensity of its respiration differed and were also related to the depth of the sampling. In the Zhukovskoe peat low-moor bog, the maximal biomass of heterotrophic microorganisms (154 ?g of C/g of peat) was found in the aerobic zone at a depth of 0 to 10 cm. In the Ozernoe bog, the maximal biomass was determined in the zone of anaerobiosis at a depth of 300 cm (1947 ? g of C/g of peat). The molecular-genetic method was used for the determination of the spectrum of the methanogens. Seven unidentified dominant forms were revealed. The species diversity of the methanogens was higher in the oligotrophic high-moor bog than in the eutrophic low-moor bog.

  12. Geochemical evidence for the hydrology of a Tamarack-peat bog, Brimfield Township, Portage County, Ohio

    SciTech Connect

    Wilson, T.P.; Miller, L.A. (Kent State Univ., OH (United States). Dept. of Geology and Water Resources)

    1992-01-01

    Peat Bogs and wetlands represent unique environmental settings what are increasingly subjected to anthropogenic stresses involving inputs of water and chemicals. This study used geochemical and hydrologic monitoring to determine the inputs and fates of elements of the Kent-Brimfield bog located in Portage County, Ohio. Based on physical and chemical information collected over one year, a model is proposed here describing the hydrologic connection between a bog and shallow ground water surrounding the bog. The chemical composition of precipitation, soil water and ground water in the bog vicinity were monitored for one year. Field measurements included water levels, pH, Eh, alkalinity and temperature. Trace metal content of the peat, the pore waters, soil water and ground waters were determined by GFAA, ICP and LIC methods. This bog was found to function as part of a perched water table aquifer. Water in the upper 3 m of the bog is found to be chemically similar to precipitation, but modified by reactions involving dissolution of mineral matter and biologic processes. The chemistry of water deeper in the bog (> 3m) resembles shallow ground water surrounding the bog, modified by weathering of underlying geologic materials and sulfate reduction. This similarity, along with ground water elevations within and outside of the bog, supports that shallow ground water interacts with, and helps maintain water levels in the upper surface of the bog. From these results, a model is proposed for the seasonal variations in hydrologic processes operating in the wetland and surrounding basin, and describes how wetlands may change seasonally from being influent to effluent systems.

  13. Terrestrial isopod community as indicator of succession in a peat bog

    PubMed Central

    Antonovi?, Ivan; Brigi?, Andreja; Sedlar, Zorana; Bedek, Jana; Šoštari?, Renata

    2012-01-01

    Abstract Terrestrial isopods were studied in the Dubravica peat bog and surrounding forest in the northwestern Croatia. Sampling was conducted using pitfall traps over a two year period. Studied peat bog has a history of drastically decrease in area during the last five decades mainly due to the process of natural succession and changes in the water level. A total of 389 isopod individuals belonging to 8 species were captured. Species richness did not significantly differ between bog, edge and surrounding forest. High species richness at the bog is most likely the result of progressive vegetation succession, small size of the bog and interspecific relationships, such as predation. With spreading of Molinia grass on the peat bog, upper layers of Sphagnum mosses become less humid and probably more suitable for forest species that slowly colonise bog area. The highest diversity was found at the edge mainly due to the edge effect and seasonal immigration, but also possibly due to high abundance and predator pressure of the Myrmica ants and lycosid spiders at the bog site. The most abundant species were Trachelipus rathkii and Protracheoniscus politus, in the bog area and in the forest, respectively. Bog specific species were not recorded and the majority of the species collected belong to the group of tyrphoneutral species. However, Hyloniscus adonis could be considered as a tyrphoxenous species regarding its habitat preferences. Most of collected isopod species are widespread eurytopic species that usually inhabit various habitats and therefore indicate negative successive changes or degradation processes in the peat bog. PMID:22536107

  14. 150 years of mercury accumulation rates in bogs in Eastern Canada

    NASA Astrophysics Data System (ADS)

    Branfireun, B. A.; Moore, T. R.; Turunen, J.; Roulet, N. T.

    2012-12-01

    Sparse, and in some cases sporadic, measurements of mercury (Hg) deposition in Canada mean that the detection of changes in deposition rates is challenging, particularly in an absence of longer term baseline data. Natural environmental archives such as lake sediments and peats have been used extensively and successfully to establish this baseline, and to detect change. We determined recent accumulation rates of mercury (Hg) using Pb-210 in both hummock and hollow peat from 23 bogs in Eastern Canada and average Hg accumulation rates were calculated for 25 year increments between ~1850 and 2000. Despite variability among sites, several important geographic and temporal patterns emerge. Between 1850 and 1900, nearly all of the locations show no change or slight increases in Hg accumulation rates, typically between ~4 and 10 ug/sq. m/yr. After 1900, more remote, northern sites show steady increases in Hg accumulation rates up to ~25 ug/sq. m/yr. More southern sites show a very different pattern, with rapid increases in Hg accumulation rates up to 55 ug/sq. m/yr between 1950-75, with subsequent decreases between 1975-2000 of nearly 50% in specific locations. Even when interpreted with caution, we believe that this data illustrate the impact of the steady increase of the global pool of gaseous elemental Hg and subsequent deposition in the northern hemisphere, and the superimposition of a fast-oxidizing pool of more reactive gaseous Hg and particulate Hg in more southern locations. The recent decrease in Hg accumulation in southern locations suggests that decreases in emissions result in reduced Hg deposition at the regional scale.

  15. Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

    Microsoft Academic Search

    MARC J. M AZEROLLE; MONIQUE P OULIN; C LAUDE L AVOIE; R OCHEFORT; B RUNO D ROLET

    2006-01-01

    SUMMARY 1. Peatlands have suffered great losses following drainage for agriculture, forestry, urbanisation, or peat mining, near inhabited areas. We evaluated the faunal and vegetation patterns after restoration of a peatland formerly mined for peat. We assessed whether bog pools created during restoration are similar to natural bog pools in terms of water chemistry, vegetation structure and composition, as well

  16. NORMS FOR FACULTY CHAIR POSITIONS AT IITK (Reference: BOG 2012/ 1st

    E-print Network

    Srivastava, Kumar Vaibhav

    NORMS FOR FACULTY CHAIR POSITIONS AT IITK (Reference: BOG 2012/ 1st Meeting, 24/03/2012) 1 s and contributions. These reports will be presented to the Senate and the BOG and will also be sent to the donor. #12;#12;

  17. EVALUATING CUMULATIVE EFFECTS OF DISTURBANCE ON THE HYDROLOGIC FUNCTION OF BOGS, FENS, AND MIRES

    EPA Science Inventory

    Few quantitative studies have been done on the hydrology of fens, bogs and mires, and consequently any predictions of the cumulative impacts of disturbances on their hydrologic functions is extremely difficult. or example, few data are available on the role of bogs and fens with ...

  18. The bog landforms of continental western Canada in relation to climate and permafrost patterns

    SciTech Connect

    Vitt, D.H.; Halsey, L.A. (Univ. of Alberta, Edmonton, Alberta (Canada)); Zoltai, S.C. (Northern Forestry Centre, Edmonton, Alberta (Canada))

    1994-02-01

    In continental western Canada, discontinuous permafrost is almost always restricted to ombrotrophic peatlands (bogs). Bogs occur mostly as islands or peninsulas in large, often complex fens or are confined to small basins. Permafrost may be present in extensive peat plateaus (or more locally as palsas) and was preceded by a well-developed layer of Sphagnum that served to insulate the peat and lower the pore water temperatures. Air photo interpretation reveals the occurrence of bogs with five types of surface physiography. Concentrated to the south are bogs without internal patterns that have never had permafrost. Dominating the mid-latitudes are bogs with internal lawns and fens with internal lawns (mostly representing former bogs) that had permafrost lenses in the past that have recently degraded. Concentrated in the northwest are peat plateaus without internal lawns or distinct collapse scars, but with permafrost; dominating in the northernmost area are peat plateaus with extensive permafrost and collapse scars. Relationships are apparent between the current - 1[degrees]C isotherm and the southern occurrence of peat plateaus and between the 0[degrees]C isotherm and the southern edge of bogs and fens with internal lawns. We interpret bogs and fens with internal lawns to represent areas where permafrost degradation is currently occurring at a greater rate than aggradation, seemingly in response to warmer regional climate, although fire frequency may also be of local importance. 54 refs., 21 figs., 2 tabs.

  19. Mechanisms involved in the re-establishment of Sphagnum dominated vegetation in rewetted bog remnants

    Microsoft Academic Search

    A. J. P. Smolders; H. B. M. Tomassen; M. van Mullekom; L. P. M. Lamers; J. G. M. Roelofs

    2003-01-01

    Restoration of peat bog vegetation inhighly degraded peatlands is generallyattempted by improving the hydrology ofthese areas. The present paper discussesand explains various restoration strategiesrelating to peat quality, water chemistryand hydrology. In some cases, (shallow)inundation of bog remnants leads to a rapidredevelopment of (floating) Sphagnumvegetation, usually when poorly humifiedSphagnum peat is still present. Afterinundation, the peat either swells up tothe newly

  20. SELECTIVITY BY SIX SNOWMELT MOSQUITO SPECIES FOR LARVAL HABITATS IN QUEBEC SUBARCTIC STRING BOGS

    Microsoft Academic Search

    ALAIN MAIRE

    Spatial distribution of the lar- val populations of 6 snow-melt mosquito spe- cies for several vast string bogs of the High- subarctic area of Lake Delorme, Quebec was analyzed using a re- ciprocal averaging (RA) analysis and a cluster analysis. Results of these analyses indicate that the vegetation of the bog ridges may be a use- ful indicator of the

  1. Spatio-temporal community structure of peat bog benthic desmids on a microscale

    E-print Network

    Spatio-temporal community structure of peat bog benthic desmids on a microscale Jiri´ Neustupa- scale transects were delimited at 4 temperate lowland peat bog localities to investigate spatial represented by dynamics of the common species. Keywords Desmidiales Á Microscale Á Microphytobenthos Á Peat

  2. Genesis of peat-bog soils in the northern taiga spruce forests of the Kola Peninsula

    SciTech Connect

    Nikonov, V.V.

    1981-01-01

    The characteristics of soil formation processes in the Peat-Bog soils of waterlogged spruce phytocenoses on the Kola Peninsula are investigated. It is found that the ash composition of the peat layer is determined primarily by the composition of the buried plant residues. The effect of the chemical composition of water feeding the peat bogs is determined. (Refs. 7).

  3. Patterns of distribution of microfungi in decomposing bog and fen plants

    Microsoft Academic Search

    Markus N. Thormann; Randolph S. Currah; Suzanne E. Bayley

    2004-01-01

    The microfungal assemblages from the litter of the dominant vegetation of a forested bog and a riverine, sedge-dominated fen in southern boreal Alberta, Canada, were investigated over a 2-year period. Canonical correspon- dence analyses showed distinctly different fungal communities associated with litter of the dominant plant species of this bog (Sphagnum fuscum (Schimp.) Klinggr.) and fen (Carex aquatilis Wahlenb. leaves

  4. Mobility of trace metals in pore waters of two Central European peat bogs

    Microsoft Academic Search

    Martin Novak; Petra Pacherova

    2008-01-01

    Vertical peat profiles can only be used as archives of past changes in pollution levels if atmogenic elements are immobile after their burial. For mobile elements, similar pore-water concentrations can be expected at different peat depths. Concentrations of Pb, Cu, Zn, Cr, Mn, Fe, Co and Cd were determined in surface bog water and bog pore water 40 cm below surface

  5. Carbon accumulation in bogs and fens after permafrost degradation in central Alaska

    Microsoft Academic Search

    M. T. Jorgenson; T. Cater; J. Roth; E. Pullman; C. Racine; J. Harden

    2007-01-01

    In the discontinuous zone in Alaska about 60% of the land area has permafrost and 5% has thermokarst terrain, which is comprised mostly of thermokarst lakes, bogs and fens. The collapse of lowland forests on seasonally saturated soils on ice-rich terrain into permanently saturated ombrotrophic bogs, dominated by Sphagnum and ericaceous shrubs, and into minerotrophic fens, dominated by herbaceous vegetation,

  6. -Linking microtopography with post-fire succession in bogs -453 Journal of Vegetation Science 16: 453-460, 2005

    E-print Network

    Benscoter, Brian W.

    - Linking microtopography with post-fire succession in bogs - 453 Journal of Vegetation Science 16 in boreal bogs vary microtopographically and are successional patterns re- producible among similar microtopographic features? Does succession preserve microtopography post-fire? Location: Boreal bog peatlands near

  7. Impacts of Fertilization on Rates of Autotrophic N2 Fixation in Salt Marshes and Cranberry Bogs of Massachusetts

    E-print Network

    Vallino, Joseph J.

    Impacts of Fertilization on Rates of Autotrophic N2 Fixation in Salt Marshes and Cranberry Bogs fixation in salt marshes and cranberry bogs of MA. I measured pools of NH4, NO3, and PO4, in addition to total C and N content of the soils of salt marshes and cranberry bogs, each under two different

  8. P\\procedures\\UAVP#6 Page 1 of 2 TITLE BOG/SUS DATA REQUESTS (HIT LIST) RESPONSE

    E-print Network

    Fernandez, Eduardo

    P\\procedures\\UAVP#6 Page 1 of 2 TITLE BOG/SUS DATA REQUESTS (HIT LIST) RESPONSE OBJECTIVE AND PURPOSE To establish a process for the Division of Facilities response to all required BOG/SUS Data Requests in a timely fashion. RESPONSIBILITY ACTION UNIVERSITY ARCHITECT & VP FOR FACILITIES Review BOG

  9. Testate amoebae as indicators of hydroseral change: An 8500 year record from Mer Bleue Bog, eastern Ontario, Canada

    E-print Network

    Patterson, Timothy

    Testate amoebae as indicators of hydroseral change: An 8500 year record from Mer Bleue Bog, eastern examines the response of testate amoebae to hydroseral and other environmental changes at Mer Bleue Bog of the bog record six stages of devel- opment: i) a quiet, brackish-water riverine phase (prior to ca. 8500

  10. Myrmecologische Nachrichten 6 29 -38 Wien, Dezember 2004 The "Black Bog Ant" Formica picea NYLANDER, 1846 a species different from

    E-print Network

    Villemant, Claire

    Myrmecologische Nachrichten 6 29 - 38 Wien, Dezember 2004 The "Black Bog Ant" Formica picea with sepa- rate zoogeography. The well-known "Black Bog Ant" ­ distributed over Europe, the Caucasus the trivial name "Black Bog Ant", is one of the worst examples for unstable and indeter- minate taxonomic

  11. ANALYSIS OF GEOLOGIC SETTINGS AND HYDROLOGIC CONDITIONS THAT AFFECT RESTORED PITCHER PLANT BOG HABITAT, SUSSEX COUNTY, VIRGINIA

    E-print Network

    Darby, Dennis

    ANALYSIS OF GEOLOGIC SETTINGS AND HYDROLOGIC CONDITIONS THAT AFFECT RESTORED PITCHER PLANT BOG for creating and restoring the natural hydrological regime that support rare pitcher plant bog habitats. We ET rates. STRATIGRAPHY Nutrient-poor saturated bogs are critical habitats for a wide range of plant

  12. Certificate approval process: 1) Certificate is approved to go to the Board of Governors (BOG) through existing processes in

    E-print Network

    VandeVord, Pamela

    1 Certificate approval process: 1) Certificate is approved to go to the Board of Governors (BOG. BOG approves certificate program to be offered. c. The Provost's Office will submit the program students: a. BOG approves certificate program to be offered. b. Undergraduate Affairs office or Graduate

  13. Using stable isotopes of water to characterize the hydrological cycle in a northern Minnesota black spruce-sphagnum bog forest

    E-print Network

    spruce-sphagnum bog forest Kaycee Reynolds Environmental Sciences Division, Oak Ridge National Laboratory-Sphagnum bog forest is located in the USDA Forest Service Marcell Experimental Forest in northern Minnesota of the hollow were used to collect water samples from the bog · Each sample run on the instrument was compared

  14. Holocene palaeoclimates from peat stratigraphy: macrofossil proxy climate records from three oceanic raised bogs in England and Ireland

    Microsoft Academic Search

    Keith E. Barber; Frank M. Chambers; Darrel Maddy

    2003-01-01

    Quantified analyses of plant macrofossil remains have been made from three profiles of peat from raised bogs spanning a distance of 425km from western Ireland to northern England. The reconstructed vegetation of each profile is related to changing bog surface wetness (BSW), and since the bogs are ombrotrophic these BSW changes are interpreted in terms of changing climate. Using age\\/depth

  15. Surface Level Fluctuation in Cedar Creek Bog, Minnesota Author(s): Murray F. Buell and Helen Foot Buell

    E-print Network

    Minnesota, University of

    Surface Level Fluctuation in Cedar Creek Bog, Minnesota Author(s): Murray F. Buell and Helen FootLEVEL FLUCTUATION IN CEDAR CREEK BOG, MINNESOTA ' MURRAY 1I. BUErL. AND)HELEN FOOT BUELL North Carolina Statc Collcgc, Ralcigh "Quaking bog" is the termpopularly appliedto a bogwhichhas developedupon a mat of Carex

  16. Variations of 18O\\/ 16O in plants from temperate peat bogs (Switzerland): implications for paleoclimatic studies

    Microsoft Academic Search

    Guillemette Ménot-Combes; Stephen J. Burns; Markus Leuenberger

    2002-01-01

    Despite the great potential of peat bogs as climatic archives, to date only few studies have focused on the climatic controls on cellulose isotopic composition in modern bog plants. This study attempts to calibrate plant–climate relationships by sampling a set of modern plant species (both vascular plants and mosses) and bog surface waters along an altitude transect in Switzerland. Isotopic

  17. Electrocoagulation treatment of peat bog drainage water containing humic substances.

    PubMed

    Kuokkanen, V; Kuokkanen, T; Rämö, J; Lassi, U

    2015-08-01

    Electrocoagulation (EC) treatment of 100 mg/L synthetic wastewater (SWW) containing humic acids was optimized (achieving 90% CODMn and 80% DOC removal efficiencies), after which real peat bog drainage waters (PBDWs) from three northern Finnish peat bogs were also treated. High pollutant removal efficiencies were achieved: Ptot, TS, and color could be removed completely, while Ntot, CODMn, and DOC/TOC removal efficiencies were in the range of 33-41%, 75-90%, and 62-75%, respectively. Al and Fe performed similarly as the anode material. Large scale experiments (1 m(3)) using cold (T = 10-11 °C) PBDWs were also conducted successfully, with optimal treatment times of 60-120 min (applying current densities of 60-75 A/m(2)). Residual values of Al and Fe (complete removal) were lower than their initial values in the EC-treated PBDWs. Electricity consumption and operational costs in optimum conditions were found to be low and similar for all the waters studied: 0.94 kWh/m(3) and 0.15 €/m(3) for SWW and 0.35-0.70 kWh/m(3) and 0.06-0.12 €/m(3) for the PBDWs (large-scale). Thus, e.g. solar cells could be considered as a power source for this EC application. In conclusion, EC treatment of PBDW containing humic substances was shown to be feasible. PMID:25973580

  18. Species Identification of Archaeological Skin Objects from Danish Bogs: Comparison between Mass Spectrometry-Based Peptide Sequencing and Microscopy-Based Methods

    PubMed Central

    Brandt, Luise Ørsted; Schmidt, Anne Lisbeth; Mannering, Ulla; Sarret, Mathilde; Kelstrup, Christian D.; Olsen, Jesper V.; Cappellini, Enrico

    2014-01-01

    Denmark has an extraordinarily large and well-preserved collection of archaeological skin garments found in peat bogs, dated to approximately 920 BC – AD 775. These objects provide not only the possibility to study prehistoric skin costume and technologies, but also to investigate the animal species used for the production of skin garments. Until recently, species identification of archaeological skin was primarily performed by light and scanning electron microscopy or the analysis of ancient DNA. However, the efficacy of these methods can be limited due to the harsh, mostly acidic environment of peat bogs leading to morphological and molecular degradation within the samples. We compared species assignment results of twelve archaeological skin samples from Danish bogs using Mass Spectrometry (MS)-based peptide sequencing, against results obtained using light and scanning electron microscopy. While it was difficult to obtain reliable results using microscopy, MS enabled the identification of several species-diagnostic peptides, mostly from collagen and keratins, allowing confident species discrimination even among taxonomically close organisms, such as sheep and goat. Unlike previous MS-based methods, mostly relying on peptide fingerprinting, the shotgun sequencing approach we describe aims to identify the complete extracted ancient proteome, without preselected specific targets. As an example, we report the identification, in one of the samples, of two peptides uniquely assigned to bovine foetal haemoglobin, indicating the production of skin from a calf slaughtered within the first months of its life. We conclude that MS-based peptide sequencing is a reliable method for species identification of samples from bogs. The mass spectrometry proteomics data were deposited in the ProteomeXchange Consortium with the dataset identifier PXD001029. PMID:25260035

  19. Fate and Transport of Road Salt During Snowmelt Through a Calcareous Fen: Kampoosa Bog, Stockbridge, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Guswa, A. J.; Pufall, A.

    2007-12-01

    Kampoosa Bog is the largest and most ecologically diverse calcareous lake-basin fen in Massachusetts. Situated within a 4.7 km2 drainage basin, the open fen (approx. 20 acres) consists of a floating mat of sedges (incl. Carex aquatilis and Cladium mariscoides) that overlie peat and lake clay deposits. Mineral weathering of marble bedrock within the drainage basin supplies highly alkaline ground and surface waters to the fen basin. The natural chemistry has been greatly altered by road salt runoff from the Massaschusetts Turnpike, and in question is whether disturbance from the Turnpike and a gas pipline has facilitated aggressive growth by the invasive species Phragmites australis. Considered to be one of the most significant rare species habitats in the state, Massachusetts has designated Kampoosa Bog an Area of Critical Environmental Concern, and a committee representing several local, regional, and state agencies, organizations, and citizens manages the wetland. The purpose of this study is to characterize the hydrologic and chemical response of the wetland during snowmelt events to understand the fate and movement of road salt (NaCl). Concentrations of Na and Cl in the fen groundwater are greatest close to the Turnpike. Concentrations decrease with distance downstream but are still greatly elevated relative to sites upstream of the Turnpike. During snowmelt events, the fen's outlet shows a sharp rise in Na and Cl concentrations at the onset of melting that is soon diluted by the added meltwater. The Na and Cl flux, however, is greatest at peak discharge, suggesting that high-flow events are significant periods of export of dissolved salts from the fen. Pure dissolution of rock salt produces an equal molar ratio between Na and Cl, and sodium and chloride imbalances in stream and ground waters suggest that ~20% of the Na is stored on cation exchange sites within the peat. The largest imbalances between Na and Cl occur deeper within the peat, where the peat is more compact and groundwater has a longer residence time. CEC measurements show that Ca>Mg>Na>K on exchange sites and suggest that Na in groundwater preferentially displaces Mg. Management questions to be addressed include what percentage of applied salt is flushed through the fen during snowmelt each year? How much salt is retained in the fen? For how long would salt concentrations remain elevated if salt application were to cease?

  20. Long-term records of atmospheric deposition of mercury in peat cores

    E-print Network

    Paris-Sud XI, Université de

    Long-term records of atmospheric deposition of mercury in peat cores from Arctic, and comparisonD dissertation February 2004 #12;Long-term records of atmospheric deposition of mercury in peat cores from Arctic in southern Ontario recorded by peat cores from three bogs: comparison with natural "background" values (past

  1. Cyclic climatic variations in climate over the past 5,500 yr reflected in raised bogs

    Microsoft Academic Search

    Bent Aaby

    1976-01-01

    Investigations of Danish raised bogs apparently indicate cyclic long term climatic variations with a periodicity of about 260 yr over the past 5,500 yr. The result could be used for modelling future climatic trends.

  2. Invertebrate community structure along a habitat-patch size gradient within a bog pool complex 

    E-print Network

    Towers, Naomi M.

    This thesis characterises species richness and community structure over a habitat-patch size gradient of a typical bog-pool complex, investigating the effect of pool size on aquatic invertebrate communities. In this study, twenty-two pools were...

  3. Mineralogical and geochemical aspects of the formation of precambrian uraniferous albities

    SciTech Connect

    Mineeva, I.G.

    1986-03-01

    As Soviet security requires that information that might indicate the location of uranium deposits be withheld, it is somewhat difficult to determine to what extent the features described are generalizations from numerous occurrences or represent a specific deposit. Nevertheless, the paper reports the complex geologic history involved (as it so often is for this element) in the concentrations of uranium to economic levels. Descriptions include: zoning, post albite processes, carbonization and ore formation, marker elements, and uranium redeposition. 7 references.

  4. Ecology of Naididae (Oligochaeta) from an alkaline bog stream: life history patterns and community structure

    Microsoft Academic Search

    Michael E. Smith

    1986-01-01

    Population and community dynamics of naidid oligochaetes were studied from June 1982–December 1983 in a sluggish, alkaline\\u000a bog stream situated within Cedarburg Bog, Ozaukee County, Wisconsin, USA. Temporal differences in periods of peak abundance\\u000a were observed for five species studied in detail: Chaetogaster diaphanus (mid-August and September), Chaetogaster diastrophus (mid-May), Dero digitata (mid-September), Dero nivea (mid-October), and Pristina leidyi (mid-October).

  5. Restoration of Raised Bogs: Mechanisms and Case Studies from the Netherlands

    Microsoft Academic Search

    Hilde B. M. Tomassen; Alfons J. P. Smolders; Schaaf van der S; Leon P. M. Lamers; Jan G. M. Roelofs

    2010-01-01

    \\u000a This chapter discusses and explains various peat bog restoration strategies relating to peat quality, water chemistry and\\u000a hydrology based on case studies from the Netherlands. Inundation of bog remnants can lead to a rapid redevelopment of (floating)\\u000a Sphagnum vegetation, usually when poorly humified Sphagnum peat is still present. After inundation, the peat either swells up to the newly created water

  6. Germination and seedling growth of bog plants in relation to the recolonization of milled peatlands

    Microsoft Academic Search

    Daniel R. Campbell; Line Rochefort

    2003-01-01

    Two controlled experiments were conducted to evaluate the potential for vascular plants to germinate and establish in milled\\u000a peatlands and to assess whether easily measured plant traits can be used to predict their probable success. Study species\\u000a included twenty species of perennial herbs, shrubs and trees occurring frequently in undisturbed bogs or abandoned milled\\u000a bogs in Québec, Canada. First, a

  7. Preliminary survey of the peat-bog Hummell Knowe Moss using various numerical methods

    Microsoft Academic Search

    R. S. Clymo

    1980-01-01

    (1)Hummell Knowe Moss is one of several fine and relatively undamaged peat bogs in northern England, close to the border with Scotland.(2)The central, eccentrically domed, mass of peat is ca 300×600 m, and much of this is 7 to 10 m deep.(3)A single profile has 8 m of bog peat overlying 2.5 m of Phragmites peat with seeds of Potamogeton

  8. Processes in the pore waters of peat deposits

    SciTech Connect

    Levshenko, T.V.; Efremova, A.G.; Galkina, Z.M.; Surkova, T.E.; Tolstov, K.A.

    1983-01-01

    The composition of the waters of modern peat bogs that have developed in the intracontinental regions under the conditions of bogs of the high-moor, mixed, and lowmoor types have been investigated for the case of a number of peat deposits of the Smolensk, Volgorad, and Pskov provinces. During the work the pH of the deposits and the C1-, Alk, SO/sup 2/-, Ca/sup 2 +/, Mg/sup 2 +/, K- contents of the pore water of modern peat beds were studied. The thickness of the deposits studied amounted to 5-7 m. Samples were taken every 0.5 m in depth. The water was separated from the deposits by pressing out.

  9. Relationship between peat geochemistry and depositional environments, Cranberry Island, Maine

    USGS Publications Warehouse

    Raymond, R., Jr.; Cameron, C.C.; Cohen, A.D.

    1987-01-01

    The Heath, Great Cranberry Island, Maine, offers a unique locality for studying lateral and vertical relationships between radically different peat types within 1 km2. The majority of The Heath is a Sphagnum moss-dominated raised bog. Surrounding the raised bog is a swamp/marsh complex containing grass, sedge, Sphagnum moss, alder, tamarack, and skunk cabbage. Swamp/ marsh-deposited peat occurs both around the margins of The Heath and under Sphagnum-dominated peat, which was deposited within the raised bog. A third peat type, dominated by herbaceous aquatics, is present underlying the swamp/marsh-dominated peat but is not present as a dominant botanical community of The Heath. The three peat types have major differences in petrographic characteristics, ash contents, and associated minerals. Sulfur contents range from a low of 0.19 wt.% (dry) within the raised bog to a high of 4.44 wt% (dry) near the west end of The Heath, where swamp/marsh peat occurring directly behind a storm beach berm has been influenced by marine waters. The presence of major geochemical variations within a 1-km2 peat deposit suggests the need for in-depth characterization of potential peat resources prior to use. ?? 1987.

  10. Holocene Paleoclimate Reconstruction in Eastern Canada: Evidence from ?18O of plant cellulose from the Mer Bleue Bog, Ottawa, Ontario

    NASA Astrophysics Data System (ADS)

    El Bilali, H.; Patterson, R.

    2009-12-01

    We present a 9000-year high resolution oxygen isotope composition of cellulose (?18Ocel) record from an ombrotrophic bog in Eastern Canada to demonstrate the potential of cellulose isotopic composition of plants from peat deposits as a proxy for paleoclimate reconstruction. We measured the ?18Ocel extracted from selected sphagnum constituent (plant macrofossils) collected from the Mer Bleue Bog. The results show that ?18Ocel follows the general trend of Holocene paleotemperature variation for this region through the last 9000 years and the Northern Hemisphere paleotemperature record for the last 2000 years. The ?18Ocel variations delineate three distinct intervals with low values corresponding to; 200 to 800 cal. yr. B.P. (Little Ice Age), 2800 to 3400 cal. yr. B.P. (similar to a cooling period reported in Western Canada and Ireland) and 4200 to 4600 cal. yr. B.P. These periods correspond well with the reconstructed Holocene sunspot numbers record based on the reconstructed 14C and 10Be based solar irradiance record. Low ?18Ocel values also occur during the well-known minima centered at about 1810 to 1820 year A.D. interval (Dalton Minimum/Tambora volcanic event). These finding suggest that solar activity may be a major forcing factor for paleotemperature variation in Eastern Canada. Time series analysis of the dataset indicates the presence of millennial scale cycles (1300 yr) comparable to the Dansgaard-Oeschger/Bond (~1500 yr) events recognized previously in paleoclimate records from around the world that have also been correlated to fluctuations in solar irradiance.

  11. High potential of nitrogen fixation in pristine, ombrotrophic bogs in Southern Patagonia

    NASA Astrophysics Data System (ADS)

    Knorr, Klaus-Holger; Horn, Marcus A.; Bahamonde Aguilar, Nelson A.; Borken, Werner

    2015-04-01

    Nitrogen (N) input in pristine peatlands occurs via natural input of inorganic N through atmospheric deposition or biological dinitrogen (N2) fixation. However, N2 fixation is to date mostly attributed to bacteria and algae associated to Sphagnum and its contribution to plant productivity and peat buildup has been often underestimated in previous studies. Based on net N storage, exceptionally low N deposition, and high abundance of vascular plants at pristine peatlands in Southern Patagonia, we hypothesized that there must be a high potential of non-symbiotic N2 fixation not limited to the occurrence of Sphagnum. To this end, we chose two ombrotrophic bogs with spots that are dominated either by Sphagnum or by vascular, cushion-forming plants and sampled peat from different depths for incubation with 15N2 to determine N2 fixation potentials. Moreover, we analyzed 15N2 fixation by a nodule-forming, endemic conifer inhabiting the peatlands. Results from 15N2 uptake were compared to the conventional approach to study N2 fixation by the acetylene reduction assay (ARA). Using 15N2 as a tracer, high non-symbiotic N2 fixation rates of 0.3-1.4 ?mol N g-1 d-1 were found down to 50 cm under micro-oxic conditions (2 vol.%) in samples from both plots either covered by Sphagnum magellanicum or by vascular cushion plants. Peat N concentrations suggested a higher potential of non-symbiotic N2 fixation under cushion plants, likely because of the availability of easily decomposable organic compounds as substrates and oxic conditions in the rhizosphere. In the Sphagnum plots, high N2 fixation below 10 cm depth would rather reflect a potential fixation that may switch on during periods of low water levels when oxygen penetrates deeper into the peat. 15N natural abundance of live Sphagnum from 0-10 cm pointed to N uptake solely from atmospheric deposition and non-symbiotic N2 fixation. 15N signatures of peat from the cushion plant plots indicated additional N supply from N mineralization. Nitrogen fixation by the conifer Lepidothamnus fonkii was exceptionally high, reaching 3.1 ?mol N g-1 d.w. d-1 detected in roots, stems, and green biomass. For L. fonkii, we could identify a specific association with Beijerinckiaceae as N2 fixing bacteria in the root nodules, whereas the rhizosphere peat was dominated by other diazotrophs. The ARA considerably underestimated N2 fixation and can thus not be recommended for peatland studies. Our findings suggest that non-symbiotic or associative N2 fixation overcomes N deficiency in different vegetation communities and has great significance for N cycling and peat accumulation in pristine peatlands.

  12. Fen to bog transitions in high latitudes: what conditions lead to permafrost aggradation?

    NASA Astrophysics Data System (ADS)

    Treat, C. C.; Jones, M.; Loisel, J.

    2014-12-01

    Northern high-latitude peatlands accumulated an estimated 436 Gt of carbon over the Holocene. Vegetation changes, such as the succession from fen to bog species, are often clearly visible in peat profiles and can be caused by organic matter accumulation or by changes in regional climate. Most peatlands developed during the early Holocene as fens under a climate that was warmer than today due to a summer insolation maximum. Subsequent transition to bogs facilitated permafrost aggradation during the mid- to late-Holocene. Teasing out permafrost aggradation in peat cores remains a challenge, as they often resemble dry bogs. However, in many locations permafrost aggradation can be assumed especially if thermokarst is evident later in the peat record (i.e., an abrupt transition from dry bog or plateau peat to wet Sphagnum riparium or even fen peat). We used a database of existing peat core records from around the northern high latitudes to determine transition of fen to bog from plant macrofossils and determined permafrost aggradation from both plant macrofossils and physical peat properties to improve constraints on methane emissions from northern peatlands throughout the Holocene. Here, we examine the spatial and temporal trends of the fen to bog transition and permafrost aggradation in the northern high latitude regions by compiling a database of existing records of macrofossil assemblages and peat properties (carbon, nitrogen, and bulk density). We find that the timing of the fen-to-bog transition varied throughout the northern high latitudes, from 5200 yr BP in Alaska and Western Canada to < 1000 yr BP in Eastern Canada and Siberia. Similarly, the first occurrences of permafrost aggradation varied across the high latitudes, ranging from 4000 yr BP in Western Canada to the Little Ice Age in southern regions and parts of Western Siberia. The spatial and temporal differences in the fen to bog transition and permafrost aggradation suggest that methane emissions differed considerably across northern high latitudes throughout the Holocene. Identifying controls of the fen-to-bog transition and permafrost aggradation in the northern high latitudes has important implications for both carbon sequestration and methane emissions from northern peatlands to the atmosphere throughout the Holocene.

  13. A new peat bog testate amoeba transfer function and quantitative palaeohydrological reconstructions from southern Patagonia

    NASA Astrophysics Data System (ADS)

    van Bellen, S.; Mauquoy, D.; Payne, R.; Roland, T. P.; Hughes, P. D.; Daley, T. J.; Street-Perrot, F. A.; Loader, N.

    2013-12-01

    Testate amoebae have been used extensively as proxies for environmental change and palaeoclimate reconstructions in European and North American peatlands. The presence of these micro-organisms in surface samples is generally significantly linked to the local water table depth (WTD) and preservation of the amoeba shells downcore allows for millennial length water table reconstructions. Peat bog archive records in southern Patagonia are increasingly the focus of palaeoecological research due to the possibility of detecting changes in the Southern Westerlies. These Sphagnum magellanicum-dominated peat bogs are characterised by a wide range of water table depths, from wet hollows to high hummocks (>100 cm above the water table). Here we present the first transfer function for this region along with ~2k-year palaeorecords from local peat bogs. A modern dataset (155 samples) was sampled along transects from five bogs in 2012 and 2013. Measurements of WTD, pH and conductivity were taken for all samples. The transfer function model was based on the 2012 dataset, while the 2013 samples served as an independent test set to validate the model. Besides the standard leave-one-out cross-validation, we applied leave-one-site-out and leave-one transect-out cross-validation, which are effective means of verifying the degree of clustering in the dataset. To ensure that the environmental gradient had been evenly sampled we quantified the root-mean-squared error of prediction (RMSEP) individually for segments of this gradient. Ordinations showed a clear hydrological gradient in amoeba assemblages, with the dominant Assulina muscorum at the dry end and Amphitrema wrightianum and Difflugia globulosa at the wet end. Canonical correspondence analysis showed that WTD was the most important environmental variable, accounting for 18% of the variance in amoeba assemblages. A weighted averaging-partial least squares model showed best performance in cross-validation, using the 2013 data as an independent test set. Any spatial autocorrelation was minimal although the model still appeared less effective in predicting WTD for sites not included in the training set. The segment-wise RMSEP showed that the WTD gradient was generally evenly sampled with RMSEP below 15 cm for most of the gradient, much lower than the standard deviation of the mean of all WTDs. Preliminary results from peat cores sampled from the same peat bogs show surprisingly stable water tables over the last ~2k years in Andorra bog but more variation in nearby Tierra Australis bog. Peat accumulation rates in Andorra bog are among the highest recorded in temperate bogs with around 4 m of peat accumulated during the last 2k years.

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

    NASA Astrophysics Data System (ADS)

    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-dominated bogs. Water table fluctuations in the cushion plant-dominated bog seem to be negligible and CH4 is mainly released from Sphagnum lawns suggesting the importance of the vegetation type for CH4 fluxes in these special ecosystems. Our results will help to understand which conditions favor the development of either a cushion plant-dominated or Sphagnum-dominated bog which is not yet known.

  15. Carbon accumulation in bogs and fens after permafrost degradation in central Alaska

    NASA Astrophysics Data System (ADS)

    Jorgenson, M. T.; Cater, T.; Roth, J.; Pullman, E.; Racine, C.; Harden, J.

    2007-12-01

    In the discontinuous zone in Alaska about 60% of the land area has permafrost and 5% has thermokarst terrain, which is comprised mostly of thermokarst lakes, bogs and fens. The collapse of lowland forests on seasonally saturated soils on ice-rich terrain into permanently saturated ombrotrophic bogs, dominated by Sphagnum and ericaceous shrubs, and into minerotrophic fens, dominated by herbaceous vegetation, can radically alter the carbon balance of boreal ecosystems. To assess the consequences of permafrost degradation on carbon storage in boreal ecosystems, we investigated accumulation rates of soil organic carbon at various stages of vegetation succession in five bogs and six fens on the Tanana Flats in central Alaska. Bogs ranged from 109 to 637 yrs in age based on calibrated radiocarbon dates. The mean carbon stock of bog peat at the oldest successional stage was 42 kg/m2. Fens ranged in age from 50 to 102 conventional radiocarbon years that could not be calibrated to calendar years. The mean carbon stock of fen peat was 20 kg/m2 at the oldest successional stage. Carbon accumulation rates slowed at later successional stages.

  16. Holocene vegetation, climate and history of a raised bog complex, northern New Zealand based on palynology, plant macrofossils and tephrochronology

    Microsoft Academic Search

    R. M. Newnham; P. J. de Lange; D. J. Lowe

    1995-01-01

    A Holocene history of vegetation, climate, and ombrogenous mire development is presented from pollen and plant macrofossil analyses of sediments at Kopouatai Bog, a large, raised, restiad bog in northern New Zealand. Tephra layers of established ages, supplemented by numerous radiocarbon dates, provide a secure chronology. The earliest peats, overlying last glacial sediments, and dated at c. 11700 radiocarbon years

  17. School of Animal, Rural and Environmental Sciences Management of carbon budgets for severely eroded upland blanket peat bogs impacts

    E-print Network

    Evans, Paul

    upland blanket peat bogs ­ impacts of restoration Blanket bog is an important carbon sink and an Annex 1 Habitat priority under the EU Habitats Directive, but in the Peak District National Park much suffers peat by Natural England as an important site for studies of vegetation history and peat erosion in the Pennines

  18. Importance of variation in water-types for water beetle fauna (Coleoptera) in Korenburgerveen, a bog remnant in the Netherlands

    Microsoft Academic Search

    Wilco C. E. P. Verberk; Gert-Jan A. van Duinen; Theo M. J. Peeters; Hans Esselink

    2001-01-01

    Effects of restoration of raised bogs on fauna are largely unknown. Here first results are presented concerning adult water beetles in Korenburgerveen, a Dutch bog remnant. A high water beetle diversity was found including rare and characteristic species. Variation in species composition and abundance could be linked to variation in water-types suggesting that for water beetles presence of variation in

  19. BOG: R-package for Bacterium and virus analysis of Orthologous Groups

    PubMed Central

    Park, Jincheol; Taslim, Cenny; Lin, Shili

    2015-01-01

    BOG (Bacterium and virus analysis of Orthologous Groups) is a package for identifying groups of differentially regulated genes in the light of gene functions for various virus and bacteria genomes. It is designed to identify Clusters of Orthologous Groups (COGs) that are enriched among genes that have gone through significant changes under different conditions. This would contribute to the detection of pathogens, an important scientific research area of relevance in uncovering bioterrorism, among others. Particular statistical analyses include hypergeometric, Mann–Whitney rank sum, and gene set enrichment. Results from the analyses are organized and presented in tabular and graphical forms for ease of understanding and dissemination of results. BOG is implemented as an R-package, which is available from CRAN or can be downloaded from http://www.stat.osu.edu/~statgen/SOFTWARE/BOG/.

  20. Palaeohydrology, fires and vegetation succession in the southern Baltic during the last 7500 years reconstructed from a raised bog based on multi-proxy data

    E-print Network

    Bern, Universität

    reconstructed from a raised bog based on multi-proxy data Mariusz Galka a , Grayna Miotk-Szpiganowicz b , Tomasz Palaeohydrology Holocene Baltic Poland We present the first 7500 yr long multi-proxy record from a raised bog) from a 7-m thick peat archive of Stki bog dated 5500 BC­AD 1250. We obtained a record of proxies

  1. Central European pine bogs change along an altitudinal gradient Zmny stedoevropskch raselinis s borovic blatkou a jejmi kzenci podl gradientu nadmosk vsky

    E-print Network

    Kucera, Jan

    Central European pine bogs change along an altitudinal gradient Zmny stedoevropských raselinis., Kucera J., Prach K., Rektoris L. & Stech M. (2008): Central European pine bogs change along an altitudinal gradient. ­ Preslia 80: 349­363. Vegetation analyses (phytosociological relevés) of 20 peat bogs

  2. Supplerende referenceliste til "Tid den relative virkelighed". Det var en bevidst beslutning i udformningen af min bog, at referencelisten skulle holdes

    E-print Network

    Uggerhøj, Ulrik I.

    udformningen af min bog, at referencelisten skulle holdes på et absolut minimum. Dette blev gjort for at give i ét bind!)5 og Tor Nørretranders' bog om Bohr og atomfysikken.6 s. 29 At det firedimensionale rum hvilesystem) med færdiggørelsen af manuskriptet til min bog udkom en vigtig artikel om tidsrejser i

  3. Interactions between Nitrogen Fixation and Methane Cycling in Northern Minnesota Peat Bogs

    NASA Astrophysics Data System (ADS)

    Warren, M. J.; Gaby, J. C.; Lin, X.; Morton, P. L.; Kostka, J. E.; Glass, J. B.

    2014-12-01

    Peatlands cover only 3% of the Earth's surface, yet store a third of soil carbon. Increasing global temperatures have the potential to change peatlands from a net sink to a net source of atmospheric carbon. N is a limiting nutrient in oligotrophic Sphagnum-dominated peatlands and biological N2 fixation likely supplies a significant but unknown fraction of N inputs. Moreover, environmental controls on diazotrophic community composition in N-limited peatlands are poorly constrained. Thus, improved understanding of feedbacks between the CH4 and N cycles is critical for predicting future changes to CH4 flux from peat bogs. We coupled measurements of N2 fixation activity measured by the acetylene (C2H2) reduction assay (ARA) with molecular analyses of expression and diversity of nifH genes encoding the molybdenum (Mo)-containing nitrogenase from two peat bogs in the Marcell Experimental Forest, Minnesota, USA. The top 10 cm of peat was sampled from the high CH4 flux S1 bog and the low CH4 flux Zim bog in April and June 2014. Despite similar N concentrations in the top 10 cm of both bogs (0.5-1.0 ?M NO2-+NO3- and 2-3 ?M NH4+), the S1 bog displayed variable ARA activity (1-100 nmol C2H4 h-1 g-1) whereas the Zim bog had consistently low ARA activity (<1 nmol C2H4 h-1 g-1). Highest ARA activity was measured in June from S1 bog hollows with higher moisture content incubated without O2 in the light (20-100 nmol C2H4 h-1 g-1). Dissolved Fe (1-25 ?M) was higher in hollow vs. hummock samples, and at S1 vs. Zim bog, while dissolved V (4-14 nM) was consistently higher than Mo (1-4 nM), suggesting that alternative V or Fe-containing nitrogenases might be present in these bogs. In contrast, Cu, an essential micronutrient for aerobic methanotrophs, was higher in hummocks (25-48 nM) than hollows (6-17 nM). The facultative methanotroph Methylocella was the dominant diazotroph in the S1 bog based on high throughput next generation sequencing of nifH cDNA amplicons. Given previous reports of C2H2 inhibition of methanotrophy, we measured CH4 consumption in the presence or absence of 1% C2H2. Preliminary results suggest minimal effect of C2H2 on CH4 oxidation. Future measurements of 15N2 incorporation coupled to molecular analysis will elucidate whether methanotroph diazotrophy was suppressed by C2H2 in ARA incubations.

  4. Late Holocene vegetation and climate change at Moraine Bog, Tiedemann Glacier, southern Coast Mountains, British Columbia

    Microsoft Academic Search

    T. A. Arsenault; John J. Clague; R. W. Mathewes

    2007-01-01

    Moraine Bog lies just outside the outermost lateral moraine of Tiedemann Glacier in the southern Coast Mountains of British Columbia. A sediment core taken from the wetland was analyzed for pollen, magnetic susceptibility, and loss on ignition to reconstruct changes in vegetation and climate during the late Holocene. Vegetation changed little between about 3500 and 2400 14C years BP. A

  5. EFFECTS OF PEAT MINING INTENSITY ON GREEN FROG (RANA CLAMITANS) OCCURRENCE IN BOG PONDS

    Microsoft Academic Search

    Marc J. Mazerolle; Mario Cormier

    2003-01-01

    We assessed whether peat mining intensity influences the use of bog ponds by green frogs ( Rana clamitans). We selected 21 ponds in three areas undergoing different levels of peat mining: 1) mined (veg- etation completely removed exposing bare peat, presence of drainage ditches with little or no water), 2) in preparation to be mined (vegetation intact but presence of

  6. BOG and Fuzzy Controllers Based Multimodal Collision Avoidance for Industrial Manipulators

    Microsoft Academic Search

    Fabrizio Romanelli; Fabio Tampalini

    2008-01-01

    In this paper a new approach, utilizing a new paradigm built on the fusion of both Bayesian occupancy grid (BOG) and fuzzy logic controller (FLC), is presented. The aim of this work is to integrate a probabilistic approach based on the Bayesian Occupancy grids together with the fuzzy logical-based approach. The advantages of this method are several: first of all

  7. UV-SENSITIVE COMPLEX PHOSPHORUS: ASSOCIATION WITH DISSOLVED HUMIC MATERIALS AND IRON IN A BOG LAKE

    EPA Science Inventory

    The concentration of UV-sensitive complex phosphorus compounds in water from an acid bog lake was linearly related to the concentration of dissolved high molecular weight humic material (DHM) both seasonally and diurnally. The first-order rate of photoreduction (Fe(+3) to Fe(+2) ...

  8. Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog

    Microsoft Academic Search

    Peter M. Lafleur; Nigel T. Roulet; Jill L. Bubier; Steve Frolking; Tim R. Moore

    2003-01-01

    Eddy covariance measurements of net ecosystem carbon dioxide (CO2) exchange (NEE) were taken at an ombrotrophic bog near Ottawa, Canada from 1 June 1998 to 31 May 2002. Temperatures during this period were above normal except for 2000 and precipitation was near normal in 1998 and 1999, above normal in 2000, and well below normal in 2001. Growing period maximum

  9. Ecology of southeastern shrub bogs (pocosins) and Carolina bays: a community profile

    SciTech Connect

    Sharitz, R.R.; Gibbons, J.W.

    1982-11-01

    Shrub bogs of the Southeast occur in areas of poorly developed internal drainage that typically but not always have highly developed organic or peat soils. Pocosins and Carolina bays are types or subclasses of shrub bogs on the coastal plains of the Carolinas and Georgia. They share roughly the same distribution patterns, soil types, floral and faunal species composition and other community attributes, but differ in geological formation. Carolina bays may contain pocosin as well as other communities, but are defined more by their unique elliptical shape and geomorphometry. The pocosin community is largely defined by its vegetation, a combination of a dense shrub understory and a sparser canopy. The community is part of a complex successional sequence of communities (sedge bogs, savannas, cedar bogs, and bay forests) that may be controlled by such factors as fire, hydroperiod, soil type, and peat depth. Pocosins and Carolina bays harbor a number of animal groups and may be locally important in their ecology. Although few species are endemic to these habitats, they may provide important refuges for a number of species. These communities are simultaneously among the least understood and most rapidly disappearing habitats of the Southeast. Forestry and agricultural clearage are current impacts.

  10. Influence of water table on carbon dioxide, carbon monoxide, and methane fluxes from taiga bog microcosms

    Microsoft Academic Search

    Dale W. Funk; E. R. Pullmann; Kim M. Peterson; Patrick M. Crill; W. D. Billings

    1994-01-01

    Hydrological changes, particularly alterations in water table level, may largely overshadow the more direct effects of global temperature increase upon carbon cycling in arctic and subarctic wetlands. Frozen cores (n=40) of intact soils and vegetation were collected from a bog near Fairbanks, Alaska, and fluxes of COâ, CHâ, and Co in response to water table variation were studied under controlled

  11. Feeding habits and dietary overlap of Naididae (Oligochaeta) from a bog stream

    Microsoft Academic Search

    Michael E. Smith; Jerry L. Kaster

    1986-01-01

    Feeding habits and dietary overlap of three species of naidid oligochaetes (Chaetogaster diastrophus, Dero digitata, Dero nivea) were studied during June 1982–December 1983 from a bog stream in Wisconsin, USA. Chaetogaster diastrophus primarily ingested diatoms, while D. digitata and D. nivea primarily ingested detritus. Dietary overlap was substantial (97–98%) between D. digitata and D. nivea using the dietary overlap coefficient.

  12. Manipulation of soil microbial community structure in bog and forest soils using chloroform fumigation

    Microsoft Academic Search

    H. E. Dickens; J. M. Anderson

    1999-01-01

    Chloroform fumigation was used to manipulate the composition of microbial communities as a means of investigating relationships between community structure and the functioning of soil processes. Soils from two upland sites, a coniferous forest and a peat bog were fumigated with chloroform for 2, 12, 24 or 72 h. Samples were then incubated at 20°C for 4 weeks to investigate

  13. Association of postfire peat accumulation and microtopography in boreal bogs1

    E-print Network

    Benscoter, Brian W.

    Association of postfire peat accumulation and microtopography in boreal bogs1 Brian W. Benscoter, Dale H. Vitt, and R. Kelman Wieder Abstract: Peatlands accumulate organic matter as peat because of disproportionate rates of production and decomposi- tion. However, peat accumulation heterogeneity has not been

  14. Liquid chromatography determination of natural dyes in extracts from historical Scottish textiles excavated from peat bogs

    Microsoft Academic Search

    Izabella Surowiec; Anita Quye; Marek Trojanowicz

    2006-01-01

    Textiles excavated from Scottish sites belonging now to the collections of the National Museums of Scotland, including seventeenth century textiles from peat bogs in the Scottish Highlands and Islands, were selected for analysis by high performance liquid chromatography with photodiode array detection (PDA HPLC) to detect whether any dyes remained and, if so, to identify their biological sources. Dye components

  15. Soil–Methanogen Interactions in Two Peatlands (Bog, Fen) in Central New York State

    Microsoft Academic Search

    Mark D. Dettling; Joseph B. Yavitt; Hinsby Cadillo-Quiroz; Christine Sun; Stephen H. Zinder

    2007-01-01

    Rates of methanogenesis vary widely in peat soils, yet the reasons are poorly known. We examined rates of methanogenesis and methanogen diversity in relation to soil chemical and biological characteristics in 2 peatlands in New York State. One was an acidic (pH < 4.5) bog dominated by Sphagnummosses and ericaceous shrubs, although deeper peat was derived from sedges. The other

  16. Lake or bog? Reconstructing baseline ecological conditions for the protected Galápagos Sphagnum peatbogs

    NASA Astrophysics Data System (ADS)

    Coffey, Emily E. D.; Froyd, Cynthia A.; Willis, Katherine J.

    2012-10-01

    This paper documents the first 10,000 year old plant macrofossil record of vegetation changes on the central island of Santa Cruz, providing information on Sphagnum bog vegetation patterns, local extinction of key taxa, and temporal successions in the Galápagos humid highlands. Vegetation change is reconstructed through examination of Holocene sedimentary sequences obtained from three Sphagnum bogs located within volcanic caldera forming the high elevation central ridge system of Santa Cruz Island. Results indicate that these specialized Sphagnum bog ecosystems are dynamic and have undergone considerable changes in vegetation composition, transitioning from diverse hygrophilous herbs and submerged aquatic ecosystems to drier Sphagnum/Pteridium bog systems, during the last 10,000 cal yr BP. Additionally a new aquatic genus previously undocumented on the islands, Elatine, was discovered at two of the study sites, but it is now extinct on the archipelago. Some of the observed vegetation successions may have been driven by climatic shifts occurring within the eastern equatorial Pacific (EEP). Other drivers including anthropogenic change are also considered significant over the last hundred years, placing strain on this naturally dynamic system. This study helps reveal patterns of change in the humid highlands over the last 10,000 cal yr BP regarding vegetation variability, climatic shifts, the historical influence of fire, tortoise disturbance, and recent anthropogenic impacts on the island.

  17. Water budget and surface-layer water storage in a Sphagnum bog in central Sweden

    Microsoft Academic Search

    Erik Kellner; Sven Halldin

    2002-01-01

    A water budget was established for the open, undisturbed bog Stormossen, central Sweden, for the growing seasons of 1996 and 1997 as a part of the NOPEX project. The water budget was complemented with data on the spatial variation of groundwater levels and water contents in different microrelief elements (ridge, hollow and ridge margin). The seasonal (24 May to 4

  18. Peat bog Records of Atmospheric Dust fluxes - Holocene palaeoenvironmental and paleoclimatic implications for South America

    NASA Astrophysics Data System (ADS)

    De Vleeschouwer, François; Vanneste, Heleen; Bertrand, Sébastien; Coronata, Andrea; Gaiero, Diego; Le Roux, Gael

    2013-04-01

    Little attention has been given to pre-anthropogenic signals recorded in peat bogs, especially in the Southern Hemisphere. Yet they are important to 1/ better understand the different particle sources during the Holocene and 2/ to tackle the linkage between atmospheric dust loads and climate change and 3/ to better understand the impact of dust on Holocene palaeoclimate and palaeoenvironments in a critical area for ocean productivity. In the PARAD project, we will explore the use of a broad range of trace elements and radiogenic isotopes (Pb, Nd, Hf) as dust proxies. Coupling these findings with biological proxies (plant macrofossils, pollen) and detailed age-depth modelling, we expect not only to identify and interpret new links between atmospheric dust chemistry and climate change. In this contribution, we will present the preliminary results on two peat records of natural atmospheric dust using the elemental and isotopic signature in Tierra del Fuego. Preliminary results on two peat sections covering the Holocene (Karukinka Bog, Chile, 8kyrs and Harberton bog, Argentina, 14kyrs) will be discussed. This encompasses density, ash content, elemental and isotopic geochemistry, macrofossil determination and radiocarbon dating. More specifically, Karukinka bog display several mineral peaks, which possible origin (soil particles, volcanism, cosmogenic dusts, marine aerosols…) will be discussed here as well as in Vanneste et al. (this conference, session Aeolian dust: Initiator, Player, and Recorder of Environmental Change).

  19. Small is beautiful: why microtopography should be included in bog hydrology

    NASA Astrophysics Data System (ADS)

    Appels, Willemijn; van der Ploeg, Martine; Oosterwoud, Marieke; Cirkel, Gijsbert; van der Zee, Sjoerd; Witte, Jan-Philip

    2014-05-01

    Microtopography can have a large effect on flow processes at the soil surface and the composition of soil water. In peat areas, microtopography is shaped by differences in species, the growth rate and transpiration of the vegetation, and the amount of water flowing from higher areas. Microtopography is often represented by a roughness parameter in hillslope hydrological models. In areas without a strong topographical gradient however, microtopography may be underestimated when accumulated in a single parameter, especially in the presence of shallow groundwater systems. In this study, we review the intricate relationships between microtopography, surface runoff, and ecohydrology in systems featuring shallow water tables. In an analogy to surface runoff, the hydrology of a raised bog can be described as a combination of open water flow on a saturated medium, instead of the traditional acrotelm-catotelm concept that only acknowledges the saturated medium. We explored water flow through the microtopography of a raised bog with a simple conceptual model that accounts explicitly for microtopographic features and the changing flow directions these may cause. With this approach we were able to investigate the activation of fast flow paths on different areas of the bog as a function of their wetness level and bog-specific morphological features, such as hummocks and hollows. Our type of approach could be used to improve the understanding of the spatial and temporal variability of rainfall-runoff responses on raised bogs. In addition, similar approaches could be used to investigate how various runoff regimes affect the mixing of water with different chemical signatures, another driver of variations of the occurrence of plant species.

  20. 15-ky Peat Paleo-Monsoon Reconstructions from Lipid Biomarker Contents of Three Bogs in China

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Zheng, Y.; Meyers, P. A.; Xie, S.

    2007-12-01

    Paleoclimate reconstructions based on lipid biomarkers from peat bogs are relatively uncommon, although this approach has been widely applied to lake sediments where it yields important histories of climate-related changes in types of vegetation and organic matter preservation. We describe stratigraphic patterns in peat lipid biomarker distributions extracted from three well-dated peat cores. One core is from the Dingnan bog on the border of Guangdong and Jiangxi Provinces of southeastern China. A second core is from the Zoige-Hongyuan bog, which is on the Qinghai-Xizang Plateau of west China on the northeast edge of the Tibetan Plateau. The third peat core is from a shallow lake that is the source of the Hani River in Jiling Province of northeastern China. The combination of the three locations provides a broad regional history of the evolution of monsoon-influenced climate in China from the late-glacial through the Holocene. The start of peat accumulation in these locations at about 15 ka indicates the onset of wetter post-glacial climate. A period of warmer climate corresponding to the Holocene Optimum between 9 ka to 5 ka is evident in greater alterations of n-alkanoic acids and n-alkanols and in the appearance of biomarkers diagnostic of greater microbial activity. Changes in local precipitation that raised the water level of the Zoige-Hongyuan bog are indicated by increases in the proportions of C23 and C25 n- alkanes that are mainly derived from submerged/floating plants and by conversion of the Dingnan bog to a lake. Alternations in submergent and emergent plant n-alkane proxies reveal millennial scale rises and falls of the water level in these bogs, thereby reflecting variations in East Asian and Indian Ocean monsoon precipitation during the Holocene. These events correlate well with cold-dry events recorded in same regions by other climatic proxies. Our results reflect Holocene instability in the Asian monsoon system and indicate that millennial-scale changes in precipitation are more sensitive than temperature in reflecting the paleo-monsoon history of China.

  1. Factors affecting the sorption of cesium in a nutrient-poor boreal bog.

    PubMed

    Lusa, M; Bomberg, M; Virtanen, S; Lempinen, J; Aromaa, H; Knuutinen, J; Lehto, J

    2015-09-01

    (135)Cs is among the most important radionuclides in the long-term safety assessments of spent nuclear fuel, due to its long half-life of 2.3 My and large inventory in spent nuclear fuel. Batch sorption experiments were conducted to evaluate the sorption behavior of radiocesium ((134)Cs) in the surface moss, peat, gyttja, and clay layers of 7-m-deep profiles taken from a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of radiocesium increased as a function of sampling depth. The highest Kd values, with a geometric mean of 3200 L/kg dry weight (DW), were observed in the bottom clay layer and the lowest in the 0.5-1.0 m peat layer (50 L/kg DW). The maximum sorption in all studied layers was observed at a pH between 7 and 9.5. The in situ Kd values of (133)Cs in surface Sphagnum moss, peat and gyttja samples were one order of magnitude higher than the Kd values obtained using the batch method. The highest in situ Kd values (9040 L/kg DW) were recorded for the surface moss layer. The sterilization of fresh surface moss, peat, gyttja and clay samples decreased the sorption of radiocesium by 38%, although the difference was not statistically significant. However, bacteria belonging to the genera Pseudomonas, Paenibacillus, Rhodococcus and Burkholderia isolated from the bog were found to remove radiocesium from the solution under laboratory conditions. The highest biosorption was observed for Paenibacillus sp. V0-1-LW and Pseudomonas sp. PS-0-L isolates. When isolated bacteria were added to sterilized bog samples, the removal of radiocesium from the solution increased by an average of 50% compared to the removal recorded for pure sterilized peat. Our results demonstrate that the sorption of radiocesium in the bog environment is dependent on pH and the type of the bog layer and that common environmental bacteria prevailing in the bog can remove cesium from the solution phase. PMID:26010098

  2. Peat and water chemistry at Big Run Bog, a peatland in the Appalachian mountains of West Virginia, USA

    Microsoft Academic Search

    R. Kelman Wieder

    1985-01-01

    At Big Run Bog, aSphagnum-dominated peatland in the unglaciated Appalachian Plateau of West Virginia, significant spatial variation in the physical and chemical properties of the peat and in surface and subsurface (30 cm deep) water chemistry was characterized. The top 40 cm of organic peat at Big Run Bog had average values for bulk density of 0.09 g · cm?3,

  3. Heathland vegetation as a bio-monitor for nitrogen deposition and source attribution using ? 15N values

    Microsoft Academic Search

    R. A. Skinner; P. Ineson; H. Jones; D. Sleep; I. D. Leith; L. J. Sheppard

    2006-01-01

    The %N and ?15N signals in foliar nitrogen (N) from four heathland species have been monitored in a blanket bog plant community subjected to different experimental inputs of wet and dry N deposition. Interactions with combined additional treatments of phosphorus (P) and potassium (K) were also investigated. Calluna vulgaris, Cladonia portentosa, Sphagnum capillifolium and Hypnum cupressiforme were harvested for 15N

  4. Heathland vegetation as a bio-monitor for nitrogen deposition and source attribution using delta N-15 values

    Microsoft Academic Search

    R. A. Skinner; P. Ineson; H. Jones; D. Sleep; I. D. Leith; L. J. Sheppard

    2006-01-01

    The %N and delta(15)N signals in foliar nitrogen (N) from four heathland species have been monitored in a blanket bog plant community subjected to different experimental inputs of wet and dry N deposition. Interactions with combined additional treatments of phosphorus (P) and potassium (K) were also investigated. Calluna vulgaris, Cladonia portentosa, Sphagnum capillifolium and Hypnum cupressiforme were harvested for N-15

  5. Atmospheric Pb deposition since the Industrial Revolution recorded by five Swiss peat profiles: Enrichment factors, fluxes, isotopic composition, and sources

    Microsoft Academic Search

    Dominik Weiss; William Shotyk; J. D. Kramers; P. G. Appleby; Andriy K. Cheburkin

    1999-01-01

    Atmospheric Pb deposition since the Industrial Revolution was studied in western, central, and southern Switzerland using five rural peat bogs. Similar temporal patterns were found in western and central Switzerland, with two distinct periods of Pb enrichment relative to the natural background: between 1880 and 1920 with enrichments ranging from 40 to 80 times, and between 1960 and 1980 with

  6. Seasonal changes of microbial communities in two shallow peat bog lakes.

    PubMed

    Lew, Sylwia; Koblížek, Michal; Lew, Marcin; Medová, Hana; Gli?ska-Lewczuk, Katarzyna; Owsianny, Pawe? Micha?

    2015-03-01

    Peat bog lakes represent important ecosystems in temperate and boreal zones. We investigated the seasonal dynamics of the microbial community in two small peat bog lakes, Ku?nik Olsowy and Ku?nik Bagienny, located in western Poland. Fluorescence in situ hybridization analyses revealed that the bacterial community was dominated by Proteobacteria and Actinobacteria, in addition to a substantial number of archaea. An infrared epifluorescence analysis demonstrated that aerobic anoxygenic phototrophs (AAPs) constituted a significant fraction of bacterial plankton (1-19%). All the bacterial groups exhibited large seasonal changes whose course differed between the studied lakes. While chlorophyll had its maximum during winter or early summer, AAPs peaked in summer, when the growth of this group was stimulated by higher irradiance and elevated water temperatures. PMID:25331011

  7. Fate of N in a peatland, Whim bog: N immobilisation in the vegetation and peat, leakage into pore water and losses as N2O depend on the form of N

    NASA Astrophysics Data System (ADS)

    Sheppard, L. J.; Leith, I. D.; Leeson, S. R.; van Dijk, N.; Field, C.; Levy, P.

    2012-07-01

    Peatlands' vast carbon reserves accumulated under low nitrogen availability. Carbon and nitrogen cycling are inextricably linked, so what are the consequences of increased reactive nitrogen deposition for the sustainability and functioning of peatlands, and does the form of the nitrogen deposition make a difference? We have addressed these questions for an ombrotrophic peatland, Whim bog in SE Scotland, using a globally unique field simulation of reactive N deposition as dry deposited ammonia and wet deposited reduced N, ammonium and oxidised N, nitrate, added as ammonium chloride or sodium nitrate. The effects of 10 yr of reactive N additions, 56 kg N ha-1 yr-1, depended on the N form. Ammonia-N deposition caused the keystone Sphagnum species, together with the main shrub Calluna and the pleurocarpous mosses to disappear, exposing up to 30% of the peat surface. This led to a significant increase in soil water nitrate and nitrous oxide emissions. By contrast wet deposited N, despite significantly reducing the cover of Sphagnum and Pleurozium moss, did not have a detrimental effect on Calluna cover nor did it significantly change soil water N concentrations or nitrous oxide emissions. Importantly 10 yr of wet deposited N did not bare the peat surface nor significantly disrupt the vegetation, enabling the N to be retained within the carbon rich peatland ecosystems. However, given the significant role of Sphagnum in maintaining conditions that retard decomposition this study suggests that all nitrogen forms will eventually compromise carbon sequestration by peatlands through loss of some keystone Sphagnum species.

  8. Effects of peat mining intensity on green frog ( Rana clamitans ) occurrence in bog ponds

    Microsoft Academic Search

    Marc J. Mazerolle; Mario Cormier

    2003-01-01

    We assessed whether peat mining intensity influences the use of bog ponds by green frogs (Rana clamitans). We selected 21 ponds in three areas undergoing different levels of peat mining: 1) mined (vegetation completely removed\\u000a exposing bare peat, prsence of drainage ditches with little or no water), 2) in preparation to be mined (vegetation intact\\u000a but presence of drainage ditches

  9. Phylogenetic Analysis and In Situ Identification of Bacteria Community Composition in an Acidic Sphagnum Peat Bog

    Microsoft Academic Search

    Svetlana N. Dedysh; Timofei A. Pankratov; Svetlana E. Belova; Irina S. Kulichevskaya; Werner Liesack

    2006-01-01

    The Bacteria community composition in an acidic Sphagnum peat bog (pH 3.9 to 4.5) was characterized by a combination of 16S rRNA gene clone library analysis, rRNA-targeted fluorescence in situ hybridization (FISH), and cultivation. Among 84 environmental 16S rRNA gene clones, a set of only 16 cloned sequences was closely related (>95% similarity) to taxonomically described organisms. Main groups of

  10. CO2 soil fluxes at bog and forest ecosystems in southern taiga of European Russia

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitrii; Ivanov, Aleksey; Vasenev, Ivan; Kurbatova, Juliya

    2015-04-01

    Bogs and spruce forests are typical natural ecosystems of the southern taiga of European Russia. They play an important role in carbon balance between soil and atmosphere. In the Central Forest Reserve (33°00' E, 56°30' N) for over 15 years conduct research of these processes. One of the research methods of CO2 emissions is the chamber method, which allows to analyze the local variation of the intensity of fluxes and its depending of the type of vegetation, microrelief and meteorological parameters. Period of measurements was 5 months - from June to November 2013-2014. In the bog were investigated 3 areas - pine boggy forest, as well as hummocks and hollows in the middle of bog. As the forest ecosystem was chosen paludified shallow-peat spruce forest. From the data obtained it can be concluded that in all ecosystems were observed 2 periods with a minimum values of CO2 emission: the first - in early July, associated with a high level of ground water and decrease the intensity of decomposition of organic matter, and the second - in November, associated with natural processes and seasonal cooling. The average intensity of CO2 emissions in summer-autumn season between all ecosystems varied greatly: in the boggy pine forest - 500 mgCO2/m2*h), hummocks - 550 mgCO2/m2*h, hollows - 290 mgCO2/m2*h) and paludified shallow-peat spruce forest - 750 mgCO2/m2*h. Based on these researches, it was found that the intensity of CO2 emissions significantly below in the bog than in paludified shallow-peat spruce forest because it is limited by the level of ground water. In the paludified shallow-peat spruce forest, fluxes are more depend on soil temperature and less on the groundwater level.

  11. UV-sensitive complex phosphorus: association with dissolved humic material and iron in a bog lake

    Microsoft Academic Search

    DAVID A. FRANCKO; ROBERT T. HEATH

    1982-01-01

    The concentration of UV-sensitive complex phosphorus compounds in water from an acid bog lake was linearly related to the concentration of dissolved high molecular weight humic material (DHM) both seasonally and diurnally. The first-order rate of photoreduction (Fe\\/sup 3 +\\/ to Fe\\/sup 2 +\\/) of DHM iron equaled the rate of release of orthophosphate (SRP) from these compounds. The rate

  12. Titanium in ombrotrophic Sphagnum mosses from various peat bogs of Germany and Belgium

    Microsoft Academic Search

    Heike Kempter; Burkhard Frenzel

    2008-01-01

    Titanium concentrations and Ti inventories (total Ti in the sample) in living Sphagnum mosses from the surfaces of eight ombrotrophic peat bogs of five different regions of Germany and Belgium were studied over a period of two years (1995–7). Six to ten peat moss samples with a given surface area (100 cm2) and length (5 cm) were collected at different sites in

  13. Dynamics of leaf minerals, bdleaf area, and biomass from hardwoods intensively grown on a peat bog

    Microsoft Academic Search

    Sune Elowson; Lars Rytter

    1988-01-01

    Water willow and grey alder were grown on a raised sphagnum bog in central Sweden. The stands were intensively treated by daily irrigation and fertilization during the growing period in order to improve site fertility. After a 2-year establishment period high production rates were achieved in willow stands, 0.8 kg stem dry weight m-2 year-1 on current plus one (C+1)

  14. Evaluating cumulative effects of disturbance on the hydrologic function of bogs, fens, and mires

    SciTech Connect

    Siegel, D.I.

    1988-01-01

    Few quantitative studies have been done on the hydrology of fens, bogs, and mires and, consequently, any predictions of the cumulative impacts of disturbances on their hydrologic functions is extremely difficult. Bogs and fens are, in a sense, hydrobiologic systems, and any evaluation of cumulative impacts on them will have to consider the complicated interactions, barely understood, among the wetland hydrology, water chemistry, and biota, and place the effect of individual wetland impacts within the context of the cumulative impacts contributed to the watershed from other geomorphic areas and land uses. It is difficult to evaluate the potential cumulative impacts on wetland hydrology because geologic settings of wetlands are often complex and the methods used to measure wetland stream flow, ground-water flow, and evapotranspiration are inexact. Their very scale makes it difficult to quantify the hydrologic function accurately. The paper reviews current understanding of the hydrologic function of bogs, fens, and mires at different scales and in different physiographic settings, and presents hypotheses on potential cumulative impacts on the hydrologic function that might occur with multiple disturbances.

  15. PT_790_BOG_rev.4 1 of 16 10/13/11 DJH Plasma-Therm 790 RIE (Reactive Ion Etcher)

    E-print Network

    Yoo, S. J. Ben

    PT_790_BOG_rev.4 1 of 16 10/13/11 DJH Plasma-Therm 790 RIE (Reactive Ion Etcher) Basic Processing Only #12;PT_790_BOG_rev.4 2 of 16 10/13/11 DJH Safety: 1. Before operating this tool #12;PT_790_BOG_rev.4 3 of 16 10/13/11 DJH 9. Some Pinch points and Vacuum sealing surfaces

  16. Towards a conceptual model of hydrological change on an abandoned cutover bog, Quebec

    NASA Astrophysics Data System (ADS)

    van Seters, Tim E.; Price, Jonathan S.

    2002-07-01

    Cutover bogs do not return to functional peatland ecosystems after abandonment because re-establishment of peat-forming mosses is poor. This paper presents a conceptual model of bog disturbance caused by peat harvesting (1942-1972), and the hydrological evolution that occurred after abandonment (1973-1998). Two adjacent bogs of similar size and origin, one harvested and the other essentially undisturbed, provide the basis for understanding what changes occurred. The model is based on historical trends evident from previous surveys of land-use, bog ecology and resource mapping; and from recent hydrological and ecological data that characterize the current condition. Water balance data and historical information suggest that runoff increased and evapotranspiration decreased following drainage, but tended towards pre-disturbance levels following abandonment, as vegetation recolonized the surface and drainage became less efficient over time. Dewatering of soil pores after drainage caused shrinkage and oxidation of the peat and surface subsidence of approximately 80 cm over 57 years. Comparisons with a nearby natural bog suggest that bulk density in the upper 50 cm of cutover peat increased from 0·07 to 0·13 g cm-3, specific yield declined from 0·14 to 0·07, water table fluctuations were 67% greater, and mean saturated hydraulic conductivity declined from 4·1 × 10-5 to 1·3 × 10-5 cm s-1. More than 25 years after abandonment, Sphagnum mosses were distributed over broad areas but covered less than 15% of the surface. Areas with good Sphagnum regeneration (>10% cover) were strongly correlated with high water tables (mean -22 cm), especially in zones of seasonal groundwater discharge, artefacts of the extraction history. Forest cover expanded from 5 to 20% of the study area following abandonment. The effect of forest growth (transpiration and interception) and drainage on lowering water levels eventually will be countered by slower water movement through the increasingly dense soil, and by natural ditch deterioration. However, without management intervention, full re-establishment of natural hydrological functions will take a very long time.

  17. Spatial variation in rates of carbon and nitrogen accumulation in a boreal bog

    SciTech Connect

    Ohlson, M. [Agricultural Univ. of Norway, Aas (Norway). Dept. of Biology and Nature Conservation; Oekland, R.H. [Univ. of Oslo (Norway)

    1998-12-01

    Although previous studies hint at the occurrence of substantial spatial variation in the accumulation rates of C and N in bogs, the extent to which rates may vary on high-resolution spatial and temporal scales is not known. A main reason for the lack of knowledge is that it is problematic to determine the precise age of peat at a given depth. The authors determined rates of carbon and nitrogen accumulation in the uppermost decimeters of a bog ecosystem using the pine method, which enables accurate dating of surface peat layers. They combined accumulation data with numerical and geostatistical analyses of the recent vegetation to establish the relationship between bog vegetation and rate of peat accumulation. Use of a laser technique for spatial positioning of 151 age-determined peat cores within a 20 x 20 m plot made it possible to give the first tine-scaled account of spatial and temporal variation in rates of mass, carbon, and nitrogen accumulation during the last century. Rates of C and N accumulation were highly variable at all spatial scales studied. For example, after {approximately}125 yr of peat growth, C and N accumulation varied by factors of five and four, respectively, from 25 to 125 g/dm{sup 2} for C, and from 0.7 to 2.6 g/dm{sup 2} for N. It takes 40 yr of peat accumulation before significant amounts of C are lost through decay. Hummocks built up by Sphagnum fuscum and S. rubellum were able to maintain average rates of C accumulation that exceed 2 g{center_dot}dm{sup {minus}2}{center_dot} yr{sup {minus}1} during 50 yr of growth. The authors argue that data on spatial variation in rates of C accumulation are necessary to understand the role of boreal peatlands in the greenhouse effect and global climate.

  18. Temperature-Induced Increase in Methane Release from Peat Bogs: A Mesocosm Experiment

    PubMed Central

    van Winden, Julia F.; Reichart, Gert-Jan; McNamara, Niall P.; Benthien, Albert; Damsté, Jaap S. Sinninghe.

    2012-01-01

    Peat bogs are primarily situated at mid to high latitudes and future climatic change projections indicate that these areas may become increasingly wetter and warmer. Methane emissions from peat bogs are reduced by symbiotic methane oxidizing bacteria (methanotrophs). Higher temperatures and increasing water levels will enhance methane production, but also methane oxidation. To unravel the temperature effect on methane and carbon cycling, a set of mesocosm experiments were executed, where intact peat cores containing actively growing Sphagnum were incubated at 5, 10, 15, 20, and 25°C. After two months of incubation, methane flux measurements indicated that, at increasing temperatures, methanotrophs are not able to fully compensate for the increasing methane production by methanogens. Net methane fluxes showed a strong temperature-dependence, with higher methane fluxes at higher temperatures. After removal of Sphagnum, methane fluxes were higher, increasing with increasing temperature. This indicates that the methanotrophs associated with Sphagnum plants play an important role in limiting the net methane flux from peat. Methanotrophs appear to consume almost all methane transported through diffusion between 5 and 15°C. Still, even though methane consumption increased with increasing temperature, the higher fluxes from the methane producing microbes could not be balanced by methanotrophic activity. The efficiency of the Sphagnum-methanotroph consortium as a filter for methane escape thus decreases with increasing temperature. Whereas 98% of the produced methane is retained at 5°C, this drops to approximately 50% at 25°C. This implies that warming at the mid to high latitudes may be enhanced through increased methane release from peat bogs. PMID:22768100

  19. Geophysical and hydrological evaluation of two bog complexes in a northern peatland: Implications for the distribution of biogenic gases at the basin scale

    Microsoft Academic Search

    Xavier Comas; Lee Slater; Andrew Reeve

    2005-01-01

    Ground penetrating radar (GPR) was used to determine peat basin geometry and the spatial distribution of free-phase biogenic gasses in two separate units of a northern peatland (Central and Southern Unit of Caribou Bog, Maine). The Central Unit is characterized by a deep basin structure (15 m maximum depth) and a raised (eccentric) bog topographic profile (up to 2 m

  20. UNDERGRADUATE CC CoSRGE CoSFP UCC COD FCM FCSA BOG CCHE Add New Major/ Program of Study X X X X X X X

    E-print Network

    Collett Jr., Jeffrey L.

    UNDERGRADUATE CC CoSRGE CoSFP UCC COD FCM FCSA BOG CCHE Add New Major/ Program of Study X X X X X X Council approval through the UCC minutes FCSA = Requiring Special Action by Faculty Council BOG = Board

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

    Microsoft Academic Search

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

    2007-01-01

    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

  2. THE ROLE OF SPHAGNUM IN THE ACID-BASE CHEMISTRY OF BOG WATERS Marselle Alexander-Ozinskas Bates College, Lewiston, ME

    E-print Network

    Vallino, Joseph J.

    THE ROLE OF SPHAGNUM IN THE ACID-BASE CHEMISTRY OF BOG WATERS Marselle Alexander-Ozinskas ­ Bates mechanisms for control of acid-base chemistry in these systems. Keywords and phrases: Sphagnum, bog, cation exchange, acidity, acid-base chemistry 1 #12;INTRODUCTION Peat-accumulating wetlands occupy 2

  3. Cycling of inorganic and organic sulfur in peat from Big Run Bog, West Virginia

    Microsoft Academic Search

    R. Kelman Wieder; Gerald E. Lang

    1988-01-01

    Total S concentration in the top 35 cm of Big Run Bog peat averaged 9.7 ?mol·g — wet mass?1 (123 ?mol·g dry mass?1). Of that total, an average of 80.8% was carbon bonded S, 10.4% was ester sulfate S, 4.5% was FeS2­S, 2.7% was FeS­S, 1.2% was elemental S, and 0.4% was SO42?­S. In peat collected in March 1986, injected

  4. Holocene monsoon variability inferred from Targo Xian peat bog in the Tangra Yumco basin, central Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Henkel, Karoline; Haberzettl, Torsten; Miehe, Sabine; Frenzel, Peter; Daut, Gerhard; Dietze, Elisabeth; Kasper, Thomas; Ahlborn, Marieke; Mäusbacher, Roland

    2013-04-01

    The Tibetan Plateau is the greatest plateau on Earth with an average altitude of 4,500 m asl. Due to its high elevation, large area and significant role in the formation of the Asian Monsoon Systems (e.g., Indian Ocean and East-Asian Summer Monsoon) it is considered to react very sensitive to climate variations. The numerous lake systems on the Tibetan Plateau represent excellent archives reflecting variations in the strength of the monsoon system in terms of hydrological changes expressed in lake level fluctuations. For example, terraces and lacustrine deposits around the saline lake Tangra Yumco indicate lake level highstands up to ~215 m higher than the present lake level. To study Holocene lake level variations we investigated a 3.6 m long sediment core recovered from a peat bog (near the Targo Xian settlement, 30°46'N, 86°40'E) on a recessional lake level terrace ~150 m above the present shoreline of Tangra Yumco. In particular, our analyses of sedimentological (grain size), geochemical (CNS and ICP-OES) and mineralogical (XRD) data allow a detailed and high-resolution interpretation of the hydrological conditions during the Holocene. The existence of two carbonate layers in the Targo Xian record, separated by a sand layer and intercalated in peat sequences at the bottom and top of the core, provide evidence for two stable lake stages at the coring position. Peat at the bottom of the core, which is radiocarbon-dated to 11,130 +130/-345 cal BP, indicates wetland conditions similar to the Recent situation (Miehe et al., submitted). After a transition zone, a layer of pure aragonitic lake marl gives evidence for a lake stage. During this stage, high values of the total inorganic carbon (TIC) and Ca/Ti ratios as well as low C/N ratios point to a stable lake due to wet climatic conditions. This carbonate layer can be correlated with a 2-3 m thick carbonate layer found in outcrops around the present lake Tangra Yumco presenting a high lake level until approx. 2.3 (+/-0.2) ka BP (OSL age, Long et al. 2012). Results of former investigations of other lakes on the Tibetan Plateau (e.g., lake Nam Co (Kasper et al., 2012)) point to a strong Indian Ocean Summer Monsoon during the Early to Mid Holocene. In the presented record, a falling lake level and a possible desiccation of the coring location is shown by a coarse sand layer including gravel. Another lake marl section above is well delimited from the other sections in its mineralogical composition as it is composed by calcite reflecting an additional lake stage at the coring site. This led to the assumption, that this second lake stage was characterized by a smaller lake with a higher detrital input which existed until approx. 930 +45/-135 cal BP. After an oscillation of dry and wet (peat production) phases a constant peat bog developed and is still present. References: Kasper, T. et al. (2012): doi: 10.1016/j.quascirev.2012.02.011 Long, H. et al. (2012): doi: 10.1016/j.quageo.2011.11.005 Miehe et al. (submitted): JOPL

  5. High-resolution Record of Holocene Climate, Vegetation, and Fire from a Raised Peat Bog, Prince Edward Island, Canadian Maritimes

    NASA Astrophysics Data System (ADS)

    Peros, M. C.; Chan, K.; Ponsford, L.; Carroll, J.; Magnan, G.

    2014-12-01

    Raised peat bogs receive all precipitation and nutrients from the atmosphere and are thus widely used archives for information on past environments and climates. In this paper we provide high-resolution multi-proxy data from a raised bog from northeastern Prince Edward Island, located in the Gulf of St. Lawrence, Canada. We studied testate amoeba (a proxy for water table depth), macrocharcoal (a proxy for local-scale fire), peat humification (a proxy for decomposition), plant macrofossils (indicative of local-scale vegetation), and organic matter content (yielding carbon accumulation rates) from a 5.5 m long core lifted from the center of Baltic Bog. Eleven AMS radiocarbon dates show that peat accumulation began before 9000 cal yr BP and continued almost uninterrupted until the present. The macrofossil data show that a transition from a sedge-dominated fen to a sphagnum-dominated bog occurred around 8000 cal yr BP, and sphagnum remained dominant in the bog throughout most of the Holocene. A testate amoeba-based reconstruction of water table depth indicates that conditions were drier during the early Holocene (~8000 to 5000 cal yr BP) and became gradually wetter into the late Holocene. In addition, a number of higher frequency shifts in precipitation are inferred throughout the Holocene on the basis of the testate amoeba and humification results. The macrocharcoal evidence indicates fire—probably in the surrounding forest—was relatively more common during the early Holocene, perhaps due to drier climate conditions. A large influx of charcoal at around 2000 cal yr BP suggests the presence of one or more major fires at this time, and a concurrent decrease in the rate of peat accumulation indicates the fire may have affected the bog itself. The data from Baltic Bog is broadly comparable to other proxy data (in particular pollen studies) from the Canadian Maritimes. This work is important because it: 1) helps us better understand the role of hydroclimatic variability in influencing peat bog ecosystems; and 2), represents one of the few peat-based records of Holocene paleoclimate from the region.

  6. Trench Logs and Scarp Data from an Investigation of the Steens Fault Zone, Bog Hot Valley and Pueblo Valley, Humboldt County, Nevada

    USGS Publications Warehouse

    Personius, Stephen F.; Crone, Anthony J.; Machette, Michael N.; Kyung, Jai Bok; Cisneros, Hector; Lidke, David J.; Mahan, Shannon A.

    2006-01-01

    Introduction: This report contains field and laboratory data from a study of the Steens fault zone near Denio, Nev. The 200-km-long Steens fault zone forms the longest, most topographically prominent fault-bounded escarpment in the Basin and Range of southern Oregon and northern Nevada. The down-to-the-east normal fault is marked by Holocene fault scarps along nearly half its length, including the southern one-third of the fault from the vicinity of Pueblo Mountain in southern Oregon to the southern margin of Bog Hot Valley (BHV) southwest of Denio, Nev. We studied this section of the fault to better constrain late Quaternary slip rates, which we hope to compare to deformation rates derived from a recently established geodetic network in the region (Hammond and Thatcher, 2005). We excavated a trench in May 2003 across one of a series of right-stepping fault scarps that extend south from the southern end of the Pueblo Mountains and traverse the floor of Bog Hot Valley, about 4 km south of Nevada State Highway 140. This site was chosen because of the presence of well-preserved fault scarps, their development on lacustrine deposits thought to be suitable for luminescence dating, and the proximity of two geodetic stations that straddle the fault zone. We excavated a second trench in the southern BHV, but the fault zone in this trench collapsed during excavation and thus no information about fault history was documented from this site. We also excavated a soil pit on a lacustrine barrier bar in the southern Pueblo Valley (PV) to better constrain the age of lacustrine deposits exposed in the trench. The purpose of this report is to present photomosaics and trench logs, scarp profiles and slip data, soils data, luminescence and radiocarbon ages, and unit descriptions obtained during this investigation. We do not attempt to use the data presented herein to construct a paleoseismic history of this part of the Steens fault zone; that history will be the subject of a future report.

  7. Mictomys borealis (northern bog lemming) and the Wisconsin paleoecology of the east-central Great Basin

    NASA Astrophysics Data System (ADS)

    Mead, Jim I.; Bell, Christopher J.; Murray, Lyndon K.

    1992-03-01

    Teeth of northern bog lemming, Mictomys borealis, are reported from Cathedral and Smith Creek caves and represent the first Wisconsin remains of the genus from the Great Basin. Specimens from Cathedral Cave, Snake Range, are associated with U-series ages of 24,000 to 15,000 yr B.P. Previous work with pollen and packrat middens, dating to the same age as the Mictomys, indicate that Smith Creek Canyon contained a riparian, locally mesic community, including Picea engelmannii (spruce), Betula sp. (birch), Cercocarpus sp. (mountain mahogany), and Artemisia sp. (sagebrush) among other species. Exposed canyon slopes and the adjacent valley apparently contained a more xeric steppe community including sagebrush and Chenopodiineae species; rocky outcrop permitted Pinus flexilis (limber pine) and P. longaeva (bristlecone pine) to grow adjacent to Lake Bonneville or low in the canyon. The region apparently experienced a dry climate (not necessarily drier than today); however, Smith Creek Canyon was fed by glacial meltwater from Mt. Moriah. The northern bog lemming probably lived only in the riparian community and possibly on the north-facing slope below Cathedral Cave. Few canyons of the Snake Range would have had the unusually mesic conditions found in Smith Creek Canyon.

  8. Phylogenetic Analysis and In Situ Identification of Bacteria Community Composition in an Acidic Sphagnum Peat Bog

    PubMed Central

    Dedysh, Svetlana N.; Pankratov, Timofei A.; Belova, Svetlana E.; Kulichevskaya, Irina S.; Liesack, Werner

    2006-01-01

    The Bacteria community composition in an acidic Sphagnum peat bog (pH 3.9 to 4.5) was characterized by a combination of 16S rRNA gene clone library analysis, rRNA-targeted fluorescence in situ hybridization (FISH), and cultivation. Among 84 environmental 16S rRNA gene clones, a set of only 16 cloned sequences was closely related (?95% similarity) to taxonomically described organisms. Main groups of clones were affiliated with the Acidobacteria (24 clones), Alphaproteobacteria (20), Verrucomicrobia (13), Actinobacteria (8), Deltaproteobacteria (4), Chloroflexi (3), and Planctomycetes (3). The proportion of cells that hybridized with oligonucleotide probes specific for members of the domains Bacteria (EUB338-mix) and Archaea (ARCH915 and ARC344) accounted for only 12 to 22% of the total cell counts. Up to 24% of the EUB338-positive cells could be assigned by FISH to specific bacterial phyla. Alphaproteobacteria and Planctomycetes were the most numerous bacterial groups (up to 1.3 × 107 and 1.1 × 107 cells g?1 peat, respectively). In contrast to conventional plating techniques, a novel biofilm-mediated enrichment approach allowed us to isolate some representatives of predominant Bacteria groups, such as Acidobacteria and Planctomycetes. This novel strategy has great potential to enable the isolation of a significant proportion of the peat bog bacterial diversity. PMID:16517660

  9. Heat transport in the Red Lake Bog, Glacial Lake Agassiz Peatlands

    USGS Publications Warehouse

    McKenzie, J.M.; Siegel, D.I.; Rosenberry, D.O.; Glaser, P.H.; Voss, C.I.

    2007-01-01

    We report the results of an investigation on the processes controlling heat transport in peat under a large bog in the Glacial Lake Agassiz Peatlands. For 2 years, starting in July 1998, we recorded temperature at 12 depth intervals from 0 to 400 cm within a vertical peat profile at the crest of the bog at sub-daily intervals. We also recorded air temperature 1 m above the peat surface. We calculate a peat thermal conductivity of 0.5 W m-1 ??C-1 and model vertical heat transport through the peat using the SUTRA model. The model was calibrated to the first year of data, and then evaluated against the second year of collected heat data. The model results suggest that advective pore-water flow is not necessary to transport heat within the peat profile and most of the heat is transferred by thermal conduction alone in these waterlogged soils. In the spring season, a zero-curtain effect controls the transport of heat through shallow depths of the peat. Changes in local climate and the resulting changes in thermal transport still may cause non-linear feedbacks in methane emissions related to the generation of methane deeper within the peat profile as regional temperatures increase. Copyright ?? 2006 John Wiley & Sons, Ltd.

  10. Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes.

    PubMed

    Hultman, Jenni; Waldrop, Mark P; Mackelprang, Rachel; David, Maude M; McFarland, Jack; Blazewicz, Steven J; Harden, Jennifer; Turetsky, Merritt R; McGuire, A David; Shah, Manesh B; VerBerkmoes, Nathan C; Lee, Lang Ho; Mavrommatis, Kostas; Jansson, Janet K

    2015-05-14

    Over 20% of Earth's terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils and a rapid shift in functional gene composition during short-term thaw experiments. However, the fate of permafrost carbon depends on climatic, hydrological and microbial responses to thaw at decadal scales. Here we use the combination of several molecular 'omics' approaches to determine the phylogenetic composition of the microbial communities, including several draft genomes of novel species, their functional potential and activity in soils representing different states of thaw: intact permafrost, seasonally thawed active layer and thermokarst bog. The multi-omics strategy reveals a good correlation of process rates to omics data for dominant processes, such as methanogenesis in the bog, as well as novel survival strategies for potentially active microbes in permafrost. PMID:25739499

  11. Comparison of different methods to determine the degree of peat decomposition in peat bogs

    NASA Astrophysics Data System (ADS)

    Biester, H.; Knorr, K.-H.; Schellekens, J.; Basler, A.; Hermanns, Y.-M.

    2014-05-01

    Peat humification or decomposition is a frequently used proxy to extract past time changes in hydrology and climate from peat bogs. During the past century several methods to determine changes in peat decomposition have been introduced. Most of these methods are operationally defined only and the chemical changes underlying the decomposition process are often poorly understood and lack validation. Owing to the chemically undefined nature of many humification analyses the comparison of results obtained by different methods is difficult. In this study we compared changes in peat decomposition proxies in cores of two peat bogs (Königsmoor, KK; Kleines Rotes Bruch, KRB) from the Harz Mountains (Germany) using C / N ratios, Fourier transform infrared spectra absorption (FTIR) intensities, Rock Eva® oxygen and hydrogen indices, ?13C and ?15N isotopic signatures and UV-absorption (UV-ABS) of NaOH peat extracts. In order to explain parallels and discrepancies between these methods, one of the cores was additionally analysed by pyrolysis gas chromatography mass spectrometry (pyrolysis-GC-MS). Pyrolysis-GC-MS data provide detailed information on a molecular level, which allows differentiation of both changes attributed to decomposition processes and changes in vegetation. Principal component analysis was used to identify and separate the effects of changes in vegetation pattern and decomposition processes because both may occur simultaneously upon changes in bog hydrology. Records of decomposition proxies show similar historical development at both sites, indicating external forcing such as climate as controlling the process. All decomposition proxies except UV-ABS and ?15N isotopes show similar patterns in their records and reflect to different extents signals of decomposition. The molecular composition of the KK core reveals that these changes are mainly attributed to decomposition processes and to a lesser extent to changes in vegetation. Changes in the molecular composition indicate that peat decomposition in the KK bog is mainly characterized by preferential decomposition of phenols and polysaccharides and relative enrichment of aliphatics during drier periods. Enrichment of lignin and other aromatics during decomposition was also observed but showed less variation than polysaccharides or aliphatics, and presumably reflects changes in vegetation associated with changes in hydrology of the bogs. Significant correlations with polysaccharide and aliphatic pyrolysis products were found for C / N ratios, FTIR-band intensities and for hydrogen index values, supporting that these decomposition indices provide reasonable information. Correlations of polysaccharide and aliphatic pyrolysis products with oxygen index values and ?13C was weaker, assumingly indicating carboxylation of the peat during drier periods and enrichment of isotopically lighter peat components during decomposition, respectively. FTIR, C / N ratio, pyrolysis-GC-MS analyses and Rock Eval hydrogen indices appear to reflect mass loss and related changes in the molecular peat composition during mineralization best. Pyrolysis-GC-MS allows disentangling the decomposition processes and vegetation changes. UV-ABS measurements of alkaline peat extracts show only weak correlation with other decomposition proxies and pyrolysis results as they mainly reflect the formation of humic acids through humification and to a lesser extent mass loss during mineralization.

  12. Development of a high resolution modeling tool for prediction of waterflows through complex mires: Example of the Mukhrino bog complex in West Siberian middle Taiga Zone

    NASA Astrophysics Data System (ADS)

    Zarov, Evgeny A.; Schmitz, Oliver; Bleuten, Wladimir

    2015-04-01

    Water flow through peat bogs differ substantially from mineral soil landscapes. Permeability of the peatlayers decrease dramatically with depth within the permanently watersaturated peat layers (Catotelm), whereas the 10-60 cm thick superficial layer (Acrotelm) has a very high conductivity. Water flows predominantly in this acrotelm layer where an open structure of stems of mosses and few plants hardly limit water flow. By omitting this superficial flow infrastructures in many places block the waterflow. Moreover, the different bog types within a complex bog have different hydrological conductivities. Without considering the typical water-flow of bogs the construction of roads and platforms for oil and gas production threatens downhill mire ecosystems by partly drainage. The objective of our study was to develop a modeling tool which can be used to predict quantitatively spatially distributed water-flow of a bog complex. A part of the extensive bog complex "Mukhrino bog complex" located at the left bank of Irtysh river near the West Siberian town Khanty-Mansiysk' was chosen as modeling area. Water discharge from this bog catchment occurs by "waterfalls" at the East margin where a scarp with ca. 8 m elevation difference has been developed by backward erosion into the bog by the Mukhrino river. From field observations it was proven that no discharge of groundwater occurred at the margin of the bog catchment area. We used PCRaster-MODFLOW as modeling environment. The model area size was 3.8 km2, cell size 5 m and the model included 3 Acrotelm layers and 3 Catotelm layers. Thickness of Acrotelm and Catotelm have been measured by coring in transects. Input data of rain, snow have been recorded in the study area. Evapotranspiration was measured with small lysimeters and crop factors for different land unit types (open water, raised bog, patterned bog, poor fens) were elaborated by water balance modeling (1-D). Land unit types have been mapped by supervised classification of a satellite image (QuickBird). For modeling open water type was split into shallow lakes and deep "primary" lakes. From the model output of water level heads and flows in three dimensions it was concluded that 95% occurs by superficial flow through the Catotelm layers. Water flow through the Catotelm occurs bit was of minor importance. With the modeling tool a virtual dam was created through the modeling area and the accumulated water-flow across this dam calculated. The tool proved to be suitable for calculation of optimization of permeability of road constructions through mires avoiding damaging the high valuable bog ecosystems.

  13. The importance of dissolved free oxygen during formation of sandstone-type uranium deposits

    USGS Publications Warehouse

    Granger, Harry Clifford; Warren, C.G.

    1979-01-01

    One factor which distinguishes t, he genesis of roll-type uranium deposits from the Uravan Mineral Belt and other sandstone-type uranium deposits may be the presence and concentration of dissolved free oxygen in the ore-forming. solutions. Although dissolved oxygen is a necessary prerequisite for the formation of roll-type deposits, it is proposed that a lack of dissolved oxygen is a prerequisite for the Uravan deposits. Solutions that formed both types of deposits probably had a supergene origin and originated as meteoric water in approximate equilibrium with atmospheric oxygen. Roll-type deposits were formed where the Eh dropped abruptly following consumption of the oxygen by iron sulfide minerals and creation of kinetically active sulfur species that could reduce uranium. The solutions that formed the Uravan deposits, on the other hand, probably first equilibrated with sulfide-free ferrous-ferric detrital minerals and fossil organic matter in the host rock. That is, the uraniferous solutions lost their oxygen without lowering their Eh enough to precipitate uranium. Without oxygen, they then. became incapable of oxidizing iron sulfide minerals. Subsequent localization and formation of ore bodies from these oxygen-depleted solutions, therefore, was not necessarily dependent on large reducing capacities.

  14. The formation of basal-type uranium deposits in south central British Columbia

    SciTech Connect

    Boyle, D.R.

    1982-08-01

    The basal-type uranium deposits in south central British Columbia occur within unconsolidated, late Miocene fluvial paleochannel sediments that overlie major fault zones within the Okanagan Highlands Intrusive Complex. Five uranium deposits have been outlined to date, of which the Blizzard (4,020 metric tons U) and Tyee (650 metric tons U) are the largest. The basement intrusive complex underlying the deposits varies in age from early Cretaceous to Eocene and is comprised of quartz monzonite, granodiorite, Coryell monzonite, porphyritic granite, and pegmatite. Uranium mineralization is present in the form of uranous (ningyoite) or uranyl (saleeite, autunite) phosphates coating clastic grains and filling voids. Because of very strong reducing conditions related to large concentrations of marcasite and organic material, ningyoite is the only uranium mineral in the Tyee deposit, whereas the Blizzard deposit contains a more complex assemblage of minerals (saleeite, autunite, ningyoite). The observed paragenetic sequence of mineral precipitation in the Blizzard deposit (autunite-saleeite-ningyoite) indicates that the uranyl minerals, saleeite and autunite, are primary. Investigations of the source of the ore-forming elements (U, Ca, Mg, PO/sub 4/) showed the deposits to be formed by the infiltration into fluvial sediments of deep-seated, structurally controlled, ground waters that migrated in a well-developed regional hydrologic system within the Complex. Research indicates that the ore-forming ground waters were cold, slightly bicarbonated (150-400 ppm), highly uraniferous (10-50 ppb), and slightly oxidizing (dissolved oxygen = 2-4 ppm).

  15. Evidence from northwest European bogs shows ‘Little Ice Age’ climatic changes driven by variations in solar activity

    Microsoft Academic Search

    Dmitri Mauquoy; Bas van Geel; Maarten Blaauw; Johannes van der Plicht

    2002-01-01

    Fluctuations in Holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity. Analyses of both 10Be and 14C nuclides con” rm that production-rate changes during the Holocene were largely modulated by solar activity. Analyses of peat samples from two intact European ombrotrophic bogs show that climatic deteriorations during the ‘Little Ice Age’ are associated with

  16. Influence of colloidal organic matter on iron and iron--phosphorus cycling in an acid bog lake

    Microsoft Academic Search

    JEFFERY P. KOENINGS; FRANK F. HOOPER

    1976-01-01

    The relationship between iron and phosphorus and the relationship of these elements to colloidal organic matter (COM ) was studied in a meromictic acid bog lake by chemi- cal characterization, filtration and in situ dialysis, and in situ experiments with labeled components. Bathophenanthroline ( BPN ) rcactivc ferrous iron existed in true solution ( dialyzable ) in constantly anaerobic monimolimnetic

  17. Carbon dioxide fluxes over a raised open bog at the Kinosheo Lake tower site during the Northern Wetlands Study (NOWES)

    Microsoft Academic Search

    H. H. Neumann; G. den Hartog; K. M. King; A. C. Chipanshi

    1994-01-01

    Measurements of carbon dioxide concentration and flux were made above a raised open bog at Lake Kinosheo in the southern Hudson Bay lowlands during the Northern Wetlands Study (NOWES) experiment in 1990. Continuous concentration measurements by infrared gas analyzers (IRGA) and spot flask samples were taken over the period July 1 to July 29. Afternoon COâ values were only 5

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

    Microsoft Academic Search

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

    2011-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methanotrophs living in and 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 diversity of methanotrophs in different Sphagnum dominated bog microhabitats. In contrast to the Northern Hemisphere peat ecosystems the temperate

  19. Profiles of Water Content and Pore Size in Sphagnum and Peat, and their Relation to Peat Bog Ecology

    Microsoft Academic Search

    P. M. Hayward; R. S. Clymo

    1982-01-01

    The bog mosses, Sphagnum, form a significant part of the total mass of plants in the world. Their rate of growth depends to a considerable extent on the supply of water to them, and different species occupy characteristic habitats which differ in their ability to supply water. We used the profiles of water content in almost undisturbed cores of two

  20. Micromorphological and (bio)chemical organic matter changes in a formerly cutover peat bog : Le Russey, Jura Mountains, France.

    E-print Network

    Paris-Sud XI, Université de

    Micromorphological and (bio)chemical organic matter changes in a formerly cutover peat bog : Le. In order to moniter peat reaccumulation and hence long-term carbon sequestration in peatlands which have ([1]). Among these indicators, it has previously been shown that physico-chemical properties of peat

  1. Isolation and identification of methanogen-specific DNA from blanket bog peat by PCR amplification and sequence analysis

    Microsoft Academic Search

    BARBARA A. HALES; CLIVE EDWARDS; DONALD A. RITCHIE; J. R. Saunders

    1996-01-01

    Methane, despite its lower concentration, is estimated to be 25 to 30 times more effective as a greenhouse gas than carbon dioxide. Estimates suggest that about 74% of atmospheric methane is derived from recent microbial activity and sources of methane are of considerable interest. This report describes the analysis of methanogen-specific DNA present in a well-characterized blanket peat bog, a

  2. Carbon and Nitrogen Isotope Variation in Peat Bogs in the Midwestern US: Implications for Holocene Climate Reconstruction

    NASA Astrophysics Data System (ADS)

    Wong, D.; Paytan, A.; Jackson, S.

    2008-12-01

    A peat core, from near the center of Minden Bog in Michigan, representing about 3500 years of accumulation was previously analyzed for plant macrofossils, colorimetric humification, and testate amoebae to yield three independent climate proxies (Booth and Jackson, 2003). The plant macrofossil data show the site to be sensitive to bog water table fluctuations. The data suggest that this may be related to regional climatic changes. We analyzed the carbon and nitrogen isotopes, as well as the carbon-nitrogen ratios in the bulk peat samples to determine if fluctuations of these records correspond to climate events as seen in the plant microfossil and amoebae records. The degree to which peat-based carbon and nitrogen isotope records reflect changes in the relative distribution of vegetation and, in turn, reflect temperature changes in effective precipitation (precipitation minus evapotranspiration) will be assessed. Peat carbon and nitrogen isotope records will be compared with existing proxy climate records and with a temperature reconstruction based on testate amoebae in bogs. We expect that climate-related changes, in the relative abundance of vegetation remains accumulating in the peat bogs, will be recorded in the organic matter in forms of carbon and nitrogen isotopes.

  3. Developing a predictive modelling capacity for a climate change-vulnerable blanket bog habitat: Assessing 1961–1990 baseline relationships

    Microsoft Academic Search

    John Coll; David Bourke; Micheline Sheehy Skeffington; John Sweeney; Michael Gormally

    2011-01-01

    Aim: Understanding the spatial distribution of high priority habitats and developing predictive models using climate and environmental variables to replicate these distributions are desirable conservation goals. The aim of this study was to model and elucidate the contributions of climate and topography to the distribution of a priority blanket bog habitat in Ireland, and to examine how this might inform

  4. Ecophysiological mechanisms characterising fen and bog species: focus on variations in nitrogen uptake traits under different soil-water pH.

    PubMed

    Nakamura, Takatoshi; Nakamura, Motoka

    2012-04-01

    Although the productivity and nitrogen (N)-use traits of mire plants differ dramatically between fens and bogs, soil N richness does not necessarily differ, whereas the soil-water pH is distinctly lower in bogs than in fens. The ecophysiological mechanisms underlying these relations are unclear. To assess the relative availability of N forms in relation to soil-water pH, we focused on the net N uptake rate per unit root weight (NNUR), glutamine synthetase activity and nitrate reductase activity, and performed reciprocal transplant experiments with the seedlings of fen (Carex lyngbyei) and bog (C. middendorffii) sedge species in intact habitat sites. The soil-water pH was clearly lower at the bog site, but the NH(4) (+), NO(3) (-) or dissolved organic-N concentrations did not differ between the fen and bog sites. The activity of both enzymes for inorganic-N assimilation did not differ among the sites and species. However, the fen species grown at bog sites showed a drastic decrease in the NNUR, suggesting a suppression of organic-N uptake. The bog species showed no NNUR difference between the sites. These results indicate that inorganic-N availability does not differ between the two habitats, but organic-N availability is lowered in a low-pH bog, particularly in the case of fen species. Therefore, the relative availability of N forms shows species-specific variations that depend on the differences in the soil-water pH of root zone, even at similar N richness, which would play a key role in plant distribution strategies in relation to the fen-bog gradient. PMID:22009342

  5. Simulated thaw development of a peat plateau-bog complex in a discontinuous permafrost region, Northwest Territories, Canada

    NASA Astrophysics Data System (ADS)

    Kurylyk, Barret; Hayashi, Masaki; Quinton, William; Voss, Clifford

    2015-04-01

    Air temperatures at high latitudes have increased at rates that exceed globally averaged trends, and this warming has produced rapid permafrost degradation in many areas. In discontinuous permafrost regions of the Taiga Plains of northwestern Canada, past climate warming has created a complex landscape mosaic of fully thawed bogs/fens and remnant peat plateaus underlain by thin permafrost. The thawing of peat plateaus can alter the landscape hydrologic connectivity by creating pathways to efficiently convey water from bogs to nearby rivers and lakes. Extensive monitoring of the thermal regime of a peat plateau-bog complex in the Scotty Creek watershed (61.3° N, 121.3° W), Northwest Territories, Canada has identified rapid permafrost degradation in the past decade. In addition, satellite images indicate major landscape evolution due to permafrost thaw since 1970, and these changes have resulted in increased discharge at the watershed outlet. These long term comprehensive data facilitate the numerical modeling of idealized permafrost environments based on observed data. The objective of this research project is to elucidate fundamental processes that contribute to multi-dimensional permafrost thaw and associated hydrological changes in discontinuous permafrost regions. The thaw evolution in this peat plateau-bog complex is simulated using SUTRA, a numerical groundwater flow and coupled heat transport model that has been modified to include dynamic freeze-thaw processes. To accommodate complex surface processes, measured climate data from 1900-2010 are used to drive a separate soil-vegetation-atmosphere energy transfer model. Near-surface temperatures produced by the vertical transfer model for the peat plateau and bog are applied as the upper thermal boundary conditions for the multi-dimensional subsurface heat transport simulations in SUTRA (1900-2010). The simulated thaw development of this peat plateau will be compared to satellite imagery to assess the ability of this sequential modeling approach to reproduce observed permafrost degradation.

  6. Purple Pitcher Plant (Sarracenia rosea) Dieback and Partial Community Disassembly following Experimental Storm Surge in a Coastal Pitcher Plant Bog

    PubMed Central

    Abbott, Matthew J.; Battaglia, Loretta L.

    2015-01-01

    Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea) are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ?1 ramet of S. rosea) were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment). There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change. PMID:25874369

  7. Purple Pitcher Plant (Sarracenia rosea) Dieback and Partial Community Disassembly following Experimental Storm Surge in a Coastal Pitcher Plant Bog.

    PubMed

    Abbott, Matthew J; Battaglia, Loretta L

    2015-01-01

    Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea) are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ?1 ramet of S. rosea) were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment). There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change. PMID:25874369

  8. Fate of N in a peatland, Whim bog: immobilisation in the vegetation and peat, leakage into pore water and losses as N2O depend on the form of N

    NASA Astrophysics Data System (ADS)

    Sheppard, L. J.; Leith, I. D.; Leeson, S. R.; van Dijk, N.; Field, C.; Levy, P.

    2013-01-01

    Peatlands represent a vast carbon reserve that has accumulated under conditions of low nitrogen availability. Given the strong coupling between the carbon and nitrogen cycles, we need to establish the consequences of the increase in reactive nitrogen deposition for the sustainability of peatlands, and whether the form in which the nitrogen is deposited makes a difference. We have addressed these questions using a globally unique field simulation of reactive N deposition as dry deposited ammonia and wet deposited reduced N, ammonium and oxidised N, nitrate, added as ammonium chloride or sodium nitrate, to an ombrotrophic peatland, Whim bog in SE Scotland. Here we report the fate of 56 kg N ha-1 yr-1 additions over 10 yr and the consequences. The effects of 10 yr of reactive N additions depended on the form in which the N was applied. Ammonia-N deposition caused the keystone Sphagnum species, together with the main shrub Calluna and the pleurocarpous mosses, to disappear, exposing up to 30% of the peat surface. This led to a significant increase in soil water nitrate and nitrous oxide emissions. By contrast wet deposited N, despite significantly reducing the cover of Sphagnum and Pleurozium moss, did not have a detrimental effect on Calluna cover nor did it significantly change soil water N concentrations or nitrous oxide emissions. Importantly 10 yr of wet deposited N did not bare the peat surface nor significantly disrupt the vegetation enabling the N to be retained within the carbon rich peatland ecosystems. However, given the significant role of Sphagnum in maintaining conditions that retard decomposition, this study suggests that all nitrogen forms will eventually compromise carbon sequestration by peatlands through loss of some keystone Sphagnum species.

  9. The Lipid Biomarker Holocene Paleoclimate Record of West China in the Zoige-Hongyuan Peat Deposit

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Zheng, Y.; Meyers, P.; Xie, S.

    2006-12-01

    Paleoclimate reconstructions based on lipid biomarkers from peat bogs are relatively uncommon, although this approach has been widely applied to lake sediments where it yields histories of climate-related changes in types of vegetation and organic matter preservation. We describe stratigraphic patterns in peat lipid biomarker distributions extracted from a well-dated peat core from the Zoige-Hongyuan peat bog. The bog is on the Qinghai-Xizang Plateau of west China on the northeast edge of the Tibetan Plateau and has accumulated a continuous deposit of peat during the latest Pleistocene and the Holocene. A period of warmer climate corresponding to the Holocene Optimum between 9 ka to 5 ka is evident in greater alterations of n-alkanoic acids and n-alkanols and in the appearance of biomarkers diagnostic of greater microbial activity. Changes in local precipitation that modified the water level of the peat bog are indicated by increases in the proportions of C23 and C25 n-alkanes that are mainly derived from submerged/floating plants. Alternations in submergent and emergent plant n-alkane proxies reveal millennial scale rises and falls of the bog water level in the Tibetan Plateau, thereby reflecting variations in Asian monsoon precipitation during the Holocene. Major low water level events occurred around 12.6, 11.3, 10.7, 9.4, 8.3, 6.0, 4.5, 3.1, 2.1, and 1.0 ka. These events correlate well with cold-dry events recorded in same region by other climatic proxies. These results reflect Holocene instability in the Asian monsoon system. Our results indicate that millennial-scale variability in precipitation is more sensitive than temperature in reflecting Asian monsoon climatic dynamics on the Tibetan Plateau.

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

    SciTech Connect

    Vogel, K.J. (Univ. of Minnesota, St. Paul (United States))

    1993-06-01

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

  11. Sphagnum ?13C Values as Potential Indicators of Palaeohydrological Changes in Peat Bogs

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Garneau, M.; Hélie, J.

    2007-12-01

    Late-Holocene peat stratigraphy of a Canadian boreal peat bog was examined in order to evaluate the potential of Sphagnum ?13C values as a surface wetness proxy indicator. Carbon isotope-inferred past moisture levels were compared to testate amoebae-inferred water table depths, and to past decomposition levels inferred by colorimetric analyses, bulk density and carbon to nitrogen ratio measurements. Analyses were carried out at the same levels, allowing relations between the different proxies. In order to establish peat chronology, six AMS radiocarbon dates were coupled with ten 210Pb dates. Proxy records were combined and compared, and since a strong correlation was found among proxies, a valuable high-resolution surface- moisture reconstruction was obtained from the core. Although the mechanisms underlying carbon fractionation processes in peatlands are not well understood, we demonstrate that Sphagnum ?13C values have a great potential for palaeohydrological reconstructions by providing a complementary source of information.

  12. Energy fluxes and evaporation mechanisms in an Atlantic blanket bog in southwestern Ireland

    NASA Astrophysics Data System (ADS)

    Sottocornola, Matteo; Kiely, Gerard

    2010-11-01

    Water and energy fluxes control the development of northern peatlands and influence their carbon budget. Blanket bogs are peatlands that occur in temperate maritime regions where precipitation is much greater than evapotranspiration (ET). In this paper, five years (October 2002-September 2007) of ET and energy fluxes derived from eddy-covariance measurements were analyzed in the context of the predicted climate change for Ireland. Monthly ET at the Glencar Atlantic blanket bog varied little, ranging between a minimum of 12 mm month-1 and a maximum of 56 mm month-1 over the five years, resulting in an annual ET average of 394 mm, with typical highest daily values of 2.5-3.0 mm. Compared to other peatland types, Glencar had lower summer ET and a lower ET/potential ET ratio, despite having higher precipitation and water table. The ET was limited not only by the low vapor pressure deficit and cool summer temperatures but also by the low cover of vascular plants and mosses (essential for transpiration). The energy budget was similar to other peatland types in terms of net radiation and sensible heat fluxes, but had lower latent and higher ground heat fluxes. A comparison among the five years suggests that the predicted climate change (greater winter precipitation, lower summer precipitation, and higher all year round temperatures) will probably increase winter ET, while the summer energy flux patterns will not be profoundly affected. However, if the frequency of summer rain events should diminish, the moss component of these ecosystems may become water stressed, ultimately leading to lower evapotranspiration.

  13. Sorption of radioiodide in an acidic, nutrient-poor boreal bog: insights into the microbial impact.

    PubMed

    Lusa, M; Bomberg, M; Aromaa, H; Knuutinen, J; Lehto, J

    2015-05-01

    Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ? 4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH. PMID:25752706

  14. Water budget and surface-layer water storage in a Sphagnum bog in central Sweden

    NASA Astrophysics Data System (ADS)

    Kellner, Erik; Halldin, Sven

    2002-01-01

    A water budget was established for the open, undisturbed bog Stormossen, central Sweden, for the growing seasons of 1996 and 1997 as a part of the NOPEX project. The water budget was complemented with data on the spatial variation of groundwater levels and water contents in different microrelief elements (ridge, hollow and ridge margin). The seasonal (24 May to 4 October) rainfall, evaporation and runoff were 200, 256, and 43 mm in 1996, respectively, and 310, 286 and 74 mm in 1997, giving negative budgets of -99 mm in 1996 and -50 mm in 1997. Approximately 60% of the total budget was caused by storage changes in the upper 40 cm of the bog and 40% by swelling/shrinking in the layers below. This mire breathing must be incorporated in future models of mire-water dynamics. The water content varied diversely among the different microrelief elements, much depending on the properties of moss and peat together with distance to water table. There also was a strong hysteresis in the relationships between groundwater level and measured volumetric water content, depending partly on pore-throat effects and partly on swelling/shrinking of the peat matrix. A seasonal variation of volumetric water content in a layer beneath water table was found to be larger than what could be justified by compression alone. We think that probable causes could be methane gas expansion together with temperature effects. The main conclusions of this study were: (i) water-transport and storage characteristics are distinctly different among hummocks, ridges and hollows, (ii) mire wetness cannot be deduced from groundwater levels only, and (iii) an important part of the total water storage was caused by swelling/shrinking of the peat, not by changes in unsaturated water content.

  15. High-resolution records of late-Holocene climate change and carbon accumulation in two north-west European ombrotrophic peat bogs

    Microsoft Academic Search

    D. S. Mauquoy; T. Engelkes; M. H. M. Groot; F. Markesteijn; M. G. Oudejans; J. van der Plicht; B. van Geel

    2002-01-01

    The peat stratigraphy (plant macrofossils, colorimetric humification, pollen\\/non-pollen microfossils, carbon\\/nitrogen ratios) of three replicate cores from a raised peat bog in the UK (Walton Moss) and a single core from a raised peat bog in Denmark (Lille Vildmose) were examined in an attempt to investigate the relation between long-term climate change and changes in species composition of the peat-forming vegetation.

  16. Electrophoretic Deposition

    NASA Astrophysics Data System (ADS)

    Brandon, David

    Electrophoresis is the migration under the influence of an electric field of charged particles held in a dispersion. Electrophoretic deposition (EPD) is then the deposition of these migrating particles onto a deposition electrode or porous membrane [1]. At a deposition electrode the charge on the particles is neutralized by the current flowing through the conducting electrode, while in a porous membrane it is the electrolyte in the part of the cell that is separated by the membrane from the dispersion that carries the neutralizing current. The two geometries are shown schematically in Fig.5.1. Deposition membranes are formed from a microporous non-conductor, while deposition electrodes have to have sufficient conductivity to carry the deposition current. In either case, the deposit closely follows the surface topology of the deposition electrode or membrane, and quite complex shapes have been produced which may either be detached from the substrate, as a freestanding component, or form an adherent surface coating.

  17. Geology and recognition criteria for sandstone uranium deposits in mixed fluvial-shallow marine sedimentary sequences, South Texas. Final report

    SciTech Connect

    Adams, S.S.; Smith, R.B.

    1981-01-01

    Uranium deposits in the South Texas Uranium Region are classical roll-type deposits that formed at the margin of tongues of altered sandstone by the encroachment of oxidizing, uraniferous solutions into reduced aquifers containing pyrite and, in a few cases, carbonaceous plant material. Many of the uranium deposits in South Texas are dissimilar from the roll fronts of the Wyoming basins. The host sands for many of the deposits contain essentially no carbonaceous plant material, only abundant disseminated pyrite. Many of the deposits do not occur at the margin of altered (ferric oxide-bearing) sandstone tongues but rather occur entirely within reduced, pyurite-bearing sandstone. The abundance of pyrite within the sands probably reflects the introduction of H/sub 2/S up along faults from hydrocarbon accumulations at depth. Such introductions before ore formation prepared the sands for roll-front development, whereas post-ore introductions produced re-reduction of portions of the altered tongue, leaving the deposit suspended in reduced sandstone. Evidence from three deposits suggests that ore formation was not accompanied by the introduction of significant amounts of H/sub 2/S.

  18. Overriding control of methane flux temporal variability by water table dynamics in a Southern Hemisphere, raised bog

    NASA Astrophysics Data System (ADS)

    Goodrich, J. P.; Campbell, D. I.; Roulet, N. T.; Clearwater, M. J.; Schipper, L. A.

    2015-05-01

    There are still large uncertainties in peatland methane flux dynamics and insufficient understanding of how biogeochemical processes scale to ecosystems. New Zealand bogs differ from Northern Hemisphere ombrotrophic systems in climatic setting, hydrology, and dominant vegetation, offering an opportunity to evaluate our knowledge of peatland methane biogeochemistry gained primarily from northern bogs and fens. We report eddy covariance methane fluxes from a raised bog in New Zealand over 2.5 years. Annual total methane flux in 2012 was 29.1 g CH4 m-2 yr-1, whereas during a year with a severe drought (2013) it was 20.6 g CH4 m-2 yr-1, both high compared to Northern Hemisphere bogs and fens. Drier conditions led to a decrease in fluxes from ~100 mg CH4 m-2 d-1 to ~20 mg CH4 m-2 d-1, and subsequent slow recovery of flux after postdrought water table rise. Water table depth regulated the temperature sensitivity of methane fluxes, and this sensitivity was greatest when the water table was within 100 mm of the surface, corresponding to the shallow rooting zone of the dominant vegetation. A correlation between daytime CO2 uptake and methane fluxes emerged during times with shallow water tables, suggesting that controls on methane production were critical in determining fluxes, more so than oxidation. Water table recession through this shallow zone led to increasing methane fluxes, whereas changes in temperature during these periods were not correlated. Models of methane fluxes should consider drought-induced lags in seasonal flux recovery that depend on drought characteristics and location of the critical zone for methane production.

  19. Multiproxy Record of Late Pleistocene–Holocene Climate and Vegetation Changes from a Peat Bog in Patagonia

    Microsoft Academic Search

    Elise Pendall; Vera Markgraf; James W. C White; Mark Dreier; Ray Kenny

    2001-01-01

    Pollen assemblage changes and stable hydrogen isotope analysis of mosses (Sphagnum magellanicum and Drepanocladus s.l.) from a bog in Tierra del Fuego, Argentina, provided independent proxies for reconstructing changes in effective moisture and temperature over the past 16,000 cal yr B.P. A deterministic model was used to reconstruct the stable hydrogen isotope composition of meteoric water from the D\\/H ratios

  20. Isolation and characterization of nitrogen-fixing bacteria of the genus Azospirillum from the soil of a Sphagnum peat bog

    Microsoft Academic Search

    E. V. Doroshenko; E. S. Boulygina; E. M. Spiridonova; T. P. Tourova; I. K. Kravchenko

    2007-01-01

    he presence of nitrogen-fixing bacteria of the genus Azospirillum in the soils of acidic raised Sphagnum bogs is revealed for the first time. Three Azospirillum strains, B2, B21, and B22, were isolated as a component of methane-oxidizing enrichment cultures, whereas attempts to isolate\\u000a them directly from peat samples have failed. The results of comparative analysis of the nucleotide sequences of

  1. Cattail invasion of sedge meadows following hydrologic disturbance in the Cowles Bog Wetland Complex, Indiana Dunes National Lakeshore

    Microsoft Academic Search

    Douglas A. Wilcox; Steven I. Apfelbaum; Ronald D. Hiebert

    1984-01-01

    The vegetation of the 80.7 hectare Cowles Bog Wetland. Complex has been altered from its historic mixed sedge-grass domination\\u000a (Carex\\u000a stricta,Calamagrostis\\u000a canadensis) in lower areas and woody growth in slightly elevated areas, as based on archival aerial photographs from 1938–1982 and recent\\u000a field data. Cattails (Typha spp.) were present in 1938 and made minor gains in cover through 1970. However,

  2. Linking glacial deposits and lake sediments for paleoclimate studies in the Northern Romanian Carpathians

    NASA Astrophysics Data System (ADS)

    Zamosteanu, Andrei; Mindrescu, Marcel; Anselmetti, Flavio; Akçar, Naki; Lowick, Sally E.; Vogel, Hendrik

    2015-04-01

    Timing and extent of glaciations in the Carpathian mountains are still controversely discussed, mostly due to the lack of well dated geomorphological and geochronological studies. We present the preliminary results of geomorphological and sedimentological analyses of glacial and lacustrine deposits in Bistricioara Valley located in the Rodna Mountains (Northern Romanian Carpathians). Most of the glacial deposits in the Romanian Carpathians, such as moraines, typically occur above 1600 m a.s.l. marking the maximum lowering of past glaciations. Most of the glacial lakes occur between 1800 and 2000 m a.s.l. Field surveys included mapping of moraines and erratic boulders using detailed topographical maps and aerial photos. A Digital Elevation Model (DEM) was derived using GIS (ArcMap 10.1) from 1:25000 topographic maps, which was further completed by field survey data. The resulting geomorphological map shows a series of moraines, which indicate the occurrence of several glacial phases in the study area. Sediment samples were collected from a peat bog (1630 m a.s.l.) dammed by a large lateral moraine within Bistricioara Mare, one of the largest glacial cirques in the Romanian Carpathians. A Russian corer was used to extract the sediment profile from the peat bog (approx. 5 m long sediment core). A X-ray computed tomography (CT) system was employed for the study of sedimentary and deformation structures and X-ray fluorescence spectroscopy (XRF) for multi-element analysis at high resolution. Glacial deposits from the lateral moraine in front of the peat bog were also sampled, as well as from the frontal moraines, upstream and downstream of the peat bog. This set of samples from multiple archives allows to link and merge the chronologies and the paleoenvironmental records of glacial deposits and lake sediments. Moreover, we employed cosmogenic nuclide dating for the reconstruction of glacial stages and their paleoclimatic implications during deglaciation in this area of Rodna Massif. The lake sediment succession showed an evolution from a basal glacially-influenced lacustrine environment to a shallow lake and eventually to a peat bog. The 5 m-long sediment core allows a good temporal resolution to document environmental and palaeoclimatic changes in the region since deglaciation. The lithostratigraphic profile exhibits several abrupt changes. The transitions from the clastic-rich lowest 30 cm of the profile to the overlying units reflects a change in the detritic input that is mostly related to initial proximity to a glacial source. The overlying sections are mostly characterized by differences in the amount of organic matter, which are in turn related to the climate variability. Anthropogenic influences cannot be discarded and will be further investigated

  3. Soil carbon balance on drained and afforested transitional bog in forest research station Vesetnieki in Latvia

    NASA Astrophysics Data System (ADS)

    Lupi?is, Ain?rs; Lazdi?š, Andis

    2015-04-01

    Around 0.8 mill. ha forests in Latvia are located on organic soils and 0.5 mill. ha of these forests are drained. Drainage of organic soils alters carbon stock and may has impact on the climate change. The aim of this study is to analyse the impact of drainage on a soil carbon stock in transitional bog (average growing stock before drainage 50 m3*ha-1) located in central part of Latvia in research station "Vesetnieki". Drainage was done in 1960. Average peat thickness is around 4.5 m; dominant tree species are pine (Pinus sylvestris L.) and spruce (Picea abies Karst.) with average growing stock 226 m3*ha-1 and 213 m3*ha-1. Volumetric peat samples were taken from soil surface down to 80 cm depth in 30 sample plots in drained sites and non-drained areas (transitional bog), which have been left as a control. Bulk density, carbon content in peat was determined to evaluate carbon stock changes in soil. Ground surface levelling in drained sites was done before drainage and repeatedly in 1966, 1970, 1975, 1977, 1982 and 2014 to calculate peat subsidence. The rate of peat subsidence after drainage increased rapidly, and 14 years after drainage 15.8 cm decrease of the surface level was found. The rate of the peat subsidence decreased later, and the ground level reduced by 9.9 cm in the following 40 years, reaching 25.7±3.5 cm from initial ground surface level in the 2014. The rapid decrease of the surface level after drainage can be explained by physical alters and by decomposition of the peat surface layers, however, it is not possible to assess now, which of these processes dominated. However, the significant (?=0.05) increase of the peat bulk density and carbon content in upper layers (0-80 cm) in drained sites compared to non-drained leads to conclusion that the compaction was the dominating process. Average carbon stock (0-80 cm deep soil layer) in non-drained areas is 339±29 tons*ha-1 and 513±27 tons*ha-1 in drained sites. We compared carbon stock in upper 80 cm soil layer in transitional bog (339±29 tons*ha-1) with peat layer in drained sites 54.3 cm corresponding to 80 cm in non-drained (359±19 tons*ha-1). The study reveals that soils in drained sites have accumulated 0.36 tons*ha-1*a-1 more carbon than soils in non-drained sites, however the difference on carbon stock between sites is not statistically significant (?=0.05). If non-drained organic soils are considered to be a carbon sink or at least not a carbon source, then we can conclude that drained organic soil in research station "Vesetnieki" in 50 years period did not become a carbon source.

  4. The microbial impact on the sorption behaviour of selenite in an acidic, nutrient-poor boreal bog.

    PubMed

    Lusa, M; Bomberg, M; Aromaa, H; Knuutinen, J; Lehto, J

    2015-09-01

    (79)Se is among the most important long lived radionuclides in spent nuclear fuel and selenite, SeO3(2-), is its typical form in intermediate redox potential. The sorption behaviour of selenite and the bacterial impact on the selenite sorption in a 7-m-deep profile of a nutrient-poor boreal bog was studied using batch sorption experiments. The batch distribution coefficient (Kd) values of selenite decreased as a function of sampling depth and highest Kd values, 6600 L/kg dry weight (DW), were observed in the surface moss and the lowest in the bottom clay at 1700 L/kg DW. The overall maximum sorption was observed at pH between 3 and 4 and the Kd values were significantly higher in unsterilized compared to sterilized samples. The removal of selenite from solution by Pseudomonas sp., Burkholderia sp., Rhodococcus sp. and Paenibacillus sp. strains isolated from the bog was affected by incubation temperature and time. In addition, the incubation of sterilized surface moss, subsurface peat and gyttja samples with added bacteria effectively removed selenite from the solution and on average 65% of selenite was removed when Pseudomonas sp. or Burkholderia sp. strains were used. Our results demonstrate the important role of bacteria for the removal of selenite from the solution phase in the bog environment, having a high organic matter content and a low pH. PMID:26048060

  5. Comparative characteristic of the sphagnum moss and peat of upland bogs in Siberia, Russia and central part of Germany

    NASA Astrophysics Data System (ADS)

    Mezhibor, Antonina; Podkozlin, Ivan

    2013-04-01

    This research represents the results of the ICP-MS study for the moss and peat samples from two upland bogs of Germany and one bog from Siberia, Russia (Tomsk region). Moss and upland peat are widely used for ecological studies. These substances enable to detect atmospheric pollution because of the peculiar structure of sphagnum moss. According to the obtained results, we can resume that moss and peat in Tomsk region are more enriched in such chemical elements as Cr, Fe, As, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Hg, Th, and U. The samples from Germany are more enriched in Mn, Cu, Zn, and Se. The geochemical composition of the bogs reflects the specificity of industries that pollute the atmosphere with definite chemical elements. Thus, REE, Th and U in the moss and peat of Tomsk region can originate from nuclear facility near the Tomsk city. Coal combustion in power stations can be the source of Cr, As, Sr and REE as well. Mn, Cu, Zn, and Se possibly can originate from metallurgical facilities in Germany.

  6. Holocene methane flux reconstruction from peat macrofossils at Siikaneva bog and fen, Finland

    NASA Astrophysics Data System (ADS)

    Mathijssen, Paul; Korrensalo, Aino; Tuittila, Eeva-Stiina; Väliranta, Minna; Mellais, Annina

    2015-04-01

    Previous studies have shown that a correlation exists between methane flux and peatland plant species abundance. Furthermore, it has been demonstrated that the composition of plant species or functional groups of species can be used as indicator for methane fluxes in peatlands, using weighted averaging. This method has the potential to be very useful in palaeoecological studies of peatlands as well. This method offers the possibility to reconstruct past methane flux based on vegetation remains still present in the peat archive and together with reconstructions of carbon accumulation can give a more complete picture of peatlands' carbon dynamics during the Holocene. Furthermore, effects of changes in hydrology or temperature on methane fluxes can be studied over much longer time scales, compared to what experimental setups allow for. For four peat cores from Siikaneva peatland in southern Finland, we reconstructed the methane flux during the Holocene. Two cores represent a part of the peatland that has currently a fen type vegetation. The other two cores were taken from a part of the peatland that has transformed into a bog, around 3.5 - 5.5 cal. year before present. The development of methane flux during the fen to bog transition is especially of interest. We used vegetation data and methane flux data from chamber measurement from all microtopographies found on Siikaneva and from a few similar peatlands in southern and central Finland as a training set. The plant species were classified into functional groups. Firstly, because it has been shown that usage of functional groups leads to better predictions of methane flux when compared to e.g. species or dominant species. Secondly, the information from the peat cores used as input for the reconstruction is based on progressively decomposed plant remains in subsequent peat layers, for which identification to species level is not always possible (most notably for sedges). We compare the predictive performance of two types of vegetation classification: one based on growth form and typical microtopography; and the other based on plant traits expected to influence methane production and transport.

  7. Respiration of soil and ground vegetation of a peat bog in southern taiga under drought stress

    NASA Astrophysics Data System (ADS)

    Tatarinov, F.; Minaeva, T.; Kurbatova, Yu.; Rusanovitch, N.

    2003-04-01

    Respiration of peat and ground vegetation (mostly sphagnum mosses) was measured by CO2 analyser LI-6400 in late August 2002 in the peat bog (Central Forest Nature Reserve, 560N, 330E, Tver region, Russia). The whole summer 2002 in the region was characterized by hot and dry weather, thus obtained data correspond to the extreme drought stress. Measurements were carried out on the 16 stationary points along the transect crossing the mire along the altitude gradient and presenting the whole range of vegetation complexes diversity: margin lag with the spruce stand and eutrophic and mesotrophic conditions; typical oligotrophic lag with pine stand and dwarf shrubs, tall sedges mesotrophic lawn, not forested hummock-hollow complex, forested hummock-hollow complex, the dwarf pine communities of different structure and at last the type of minerotrophic margin with meadow vegetation. As a “zero-point” the spruce forest on the land was appointed as the measurement point. The transect under study is the object of the long-term observations on the ground vegetation and groundwater parameters, which were related to obtained respiration values. The measured mean values of ground respiration were 4.9, 6.8, 7.5, 4.8, 3.9 and 3.7 mkmol m-2s-1 for spruce stand (bare soil), paludified spruce stand, pine mire margin, dwarf pine communities oligotrophic and minerotrophic part of the mire, respectively. Within the open peat bog hummock-hollow complex significantly higher respiration was observed for hummocks comparatively to the hollows: 6.6 and 4.2 mkmol m-2s-1, correspondingly. Significant correlation of ground respiration to the groundwater level and temperature difference between peat and air was observed. The study was carried out within the framework of international project TCOS. The data on the spatial variation of dark respiration depending on the vegetation structure and groundwater regime is considered as a background for the further functional patterns for the virgin mire ecosystems of the Russian Plain.

  8. Atmospheric Deposition

    Microsoft Academic Search

    Kathleen C. Weathers; Alexandra G. Ponette-González

    \\u000a Atmospheric deposition plays a key role in the biogeochemistry of temperate, tropical, and boreal forests. Many essential\\u000a macro- and micronutrients as well as pollutants are delivered from the atmosphere to forest ecosystems: (1) dissolved in rain\\u000a and snow (wet deposition); (2) directly as particles and gases (dry deposition); and (3) dissolved in cloud droplets (cloud,\\u000a occult, or fog deposition, hereafter

  9. Characterization of Groundwater Flow Processes in the Cedar Creek Watershed and the Cedarburg Bog in Southeastern Wisconsin

    NASA Astrophysics Data System (ADS)

    Graham, J. P.; Han, W. S.; Feinstein, D.; Hart, D. J.

    2014-12-01

    The purpose of this study is to characterize the geology and groundwater flow of the bog as well as the surrounding area, notably the Cedar Creek Watershed, a HUC (Hydrologic Unit Code) 12 watershed. The watershed is approximately 330 km2, and borders the sub-continental divide separating the Mississippi River Basin from the Great Lakes Basin. The Cedar Creek watershed is composed of mostly agricultural and urban land with a significant stress of groundwater withdrawal for both irrigation and residential use. This watershed has importance due to the contribution to both the Milwaukee River and Lake Michigan, and is integral in the study of regional groundwater flow of Southeastern Wisconsin. Furthermore, the Cedarburg Bog, located in the northeast corner of the Cedar Creek Watershed preserves diverse ecology and is recognized by the U.S. Department of Interior as a National Landmark. Groundwater is the primary driver for the diverse and unique ecology that is contained within the bog. Within the Cedar Creek Watershed, well data and glacial geology maps (Mickelson and Syverson, 1997) were integrated to develop a 3-dimensional subsurface map and watershed-scale groundwater flow model using the LAK3 and the SFR2 package to simulate surface water-aquifer interactions. The model includes 10 zones of the glacial sediments and the weathered and consolidated Silurian Dolomite bedrock. The hydraulic conductivity and storage parameters were calibrated with 203 head targets using universal parameter estimation code (PEST). Then, a series of future climate scenarios, developed by the Wisconsin Initiative on Climate Change Impact, were implemented to the USGS Soil-Water-Balance Code (SWB) to identify variations in recharge. The simulated recharge scenarios were adopted to predict the response of groundwater resources in the watershed and the Cedarburg Bog. Preliminary results produced from the MODFLOW model indicate the bog is acting as a recharge zone under current recharge conditions, approximately 12.7cm/year, with regional groundwater flow from the groundwater divide to Lake Michigan and a mean residual on calibration targets of 4.32mKnowledge acquired from this investigation can be used to better inform local agencies of potential threats, as well as predict future changes within this groundwater system.

  10. Late Holocene peatland carbon dynamics inferred from Teringi Bog in southern Estonia

    NASA Astrophysics Data System (ADS)

    Hill, Kristyn; Stansell, Nathan; Klein, Eric; Borges, Alberto

    2015-04-01

    Radiocarbon dated peat cores collected along a transect from Teringi Bog, an ombotrophic peatland, record changes in carbon accumulation rates during the late Holocene in response to shifting climatic conditions. Stable oxygen isotope records from nearby lakes indicate that periods of wetter conditions during the Holocene occurred at times when carbon accumulation rates were higher at Teringi. This suggests that shifting water table conditions drove much of the observed changes in carbon dynamics. Modern surface process observations indicate that carbon accumulation rates are indeed more variable at locations where the height of the water table is highly sensitive to rainfall amounts. In addition, carbon isotopes measured on water samples indicate that there is a close relationship between ?13C values and methane concentrations, suggesting that methanogenesis is strongly biomediated, and likewise varies as a function of the regional hydrology. Regardless, all of the cores collected indicate that there was a trend toward higher carbon accumulation rates from ~4.2 to 3.5 ka when precipitation amounts were higher, followed by lower values under drier conditions until ~2.8 ka. There was then a trend toward higher carbon accumulation rates through the remaining late Holocene. These observations further highlight the importance of high latitude peatland in global carbon dynamics as both a potential sink and source of CO2 and CH4.

  11. Reliance on prey-derived nitrogen by the carnivorous plant Drosera rotundifolia decreases with increasing nitrogen deposition.

    PubMed

    Millett, J; Svensson, B M; Newton, J; Rydin, H

    2012-07-01

    • Carnivory in plants is presumed to be an adaptation to a low-nutrient environment. Nitrogen (N) from carnivory is expected to become a less important component of the N budget as root N availability increases. • Here, we investigated the uptake of N via roots versus prey of the carnivorous plant Drosera rotundifolia growing in ombrotrophic bogs along a latitudinal N deposition gradient through Sweden, using a natural abundance stable isotope mass balance technique. • Drosera rotundifolia plants receiving the lowest level of N deposition obtained a greater proportion of N from prey (57%) than did plants on bogs with higher N deposition (22% at intermediate and 33% at the highest deposition). When adjusted for differences in plant mass, this pattern was also present when considering total prey N uptake (66, 26 and 26 ?g prey N per plant at the low, intermediate and high N deposition sites, respectively). The pattern of mass-adjusted root N uptake was opposite to this (47, 75 and 86 ?g N per plant). • Drosera rotundifolia plants in this study switched from reliance on prey N to reliance on root-derived N as a result of increasing N availability from atmospheric N deposition. PMID:22506640

  12. Characterization of the efficiency of sedimentation basins downstream of harvested peat bogs

    NASA Astrophysics Data System (ADS)

    Samson-Do, Myriam; St-Hilaire, André

    2015-04-01

    Peat harvesting is a very lucrative industry in the provinces of Quebec and New-Brunswick (Canada). Peat enters in many potting mix used for horticulture. However, harvesting this resource has some impacts on the environment. First, industries need to drain the peat bog to dry the superficial layer. Then, it is harvested with industrial vacuums and the underlying layer is allowed to dry. The drained water is laden with suspended sediments (mostly organic peat fibers) that may affect biota of the stream where it is discharged. To counter the problem, this water does not go directly on the stream but first flows through a sedimentation basin, built to reduce suspended sediment loads. This work focuses on characterizing and eventually modeling the efficiency of those sedimentation basins. Seven basins were studied in Rivière-du-Loup, St-Valère and Escoumins (Quebec, Canada). They each have a different ratio basin area/drained area (4.7 10-4 to 20.3 10-4). To continuously monitor the sediment loads (calculated from sediment concentrations and discharge) entering and leaving basins, a nephelometer and a level logger were installed in the water column upstream and downstream of sedimentation basins. Their trapping efficiency was measured during the ice-free period (May to October) and for each significant rain event, since it is known that the rain and subsequent runoff induce most of the peat transport in and out of the basin. Results show that the event efficiency decreases as the basin is filled up with trapped sediments. For one basin, the efficiency was 85August. Trapping efficiency can be used as a tool to estimate basin dimensions. This has been done for municipal sedimentation ponds that trap minerals and will be adapted to the current context, where the dominant sediment is organic.

  13. Carbon cycling responses to a water table drawdown and decadal vegetation changes in a bog

    NASA Astrophysics Data System (ADS)

    Talbot, J.; Roulet, N. T.

    2009-12-01

    The quantity of carbon stored in peat depends on the imbalance between production and decomposition of organic matter. This imbalance is mainly controlled by the wetness of the peatland, usually described by the water table depth. However, long-term processes resulting from hydrological changes, such as vegetation succession, also play a major role in the biogeochemistry of peatlands. Previous studies have looked at the impact of a water table lowering on carbon fluxes in different types of peatlands. However, most of these studies were conducted within a time frame that did not allow the examination of vegetation changes due to the water table lowering. We conducted a study along a drainage gradient resulting from the digging of a drainage ditch 85 years ago in a portion of the Mer Bleue bog, located near Ottawa, Canada. According to water table reconstructions based on testate amoeba, the drainage dropped the water table by approximately 18 cm. On the upslope side of the ditch, the water table partly recovered and the vegetation changed only marginally. However, on the downslope side of the ditch, the water table stayed persistently lower and trees established (Larix and Betula). The importance of Sphagnum decreased with a lower water table, and evergreen shrubs were replaced by deciduous shrubs. The water table drop and subsequent vegetation changes had combined and individual effects on the carbon functioning of the peatland. Methane fluxes decreased because of the water table lowering, but were not affected by vegetation changes, whereas respiration and net ecosystem productivity were affected by both. The carbon storage of the system increased because of an increase in plant biomass, but the long-term carbon storage as peat decreased. The inclusion of the feedback effect that vegetation has on the carbon functioning of a peatland when a disturbance occurs is crucial to simulate the long-term carbon balance of this ecosystem.

  14. Holocene peat development in the Pyeongtaek blanket peat bog, Korea: Preliminary results

    NASA Astrophysics Data System (ADS)

    Nahm, W.; Yi, S.; Kim, J.; Park, Y.; Kim, J.; Yang, D.; Doh, S.; Yu, K.

    2006-12-01

    Preliminary results of multi-pronged investigation of two peat trench sections from the Pyeongtaek blanket peat bog, mid-western Korean Peninsula are reported. Multiple peat layers are recorded from both HS (Hwangsan) and HY (Hwayang) trench sections. Peat layers are typically underlain by homogeneous, dark olive black (2.5Y 3/3) to olive black (7.5Y 2/2) mud with <10 wt% of total organic carbon (TOC). Abundant plant fragments and Trapa (water Chestnut) can be found in the mud layer. The peat layers (HS Unit 3; HY Unit 3) are mostly consisting of partly decomposed vegetal remains with higher (more than 30 wt%) but varying TOC content. The TOC/TN ratios range from 10 to 20 in general. The 14C age of peat layers indicates that these layers to be about 6200 14C yrBP (HY Unit 3) and 6130 14C yrBP (HS Unit 3). Magnetic susceptibility (MS) of sediment is a physical property controlled by the concentration of magnetic minerals in detrital sediment, and thus high MS could serve as an analogous evidence for enhanced sediment transportation. Peaks in MS occur in HS Units 4 and 6 as well as in HY Units 4 and 6, indicating an increase in magnetic mineral concentration. It has been found that TOC content of peat layers shows negative correlation to MS value. The onset of peat accumulation in the study area started around 6130~6200 14C yrBP, possibly the result of decrease in precipitation. The age of low TOC layers (HS Units 4 and 6; HY Units 4 and 6) is different from each section, indicating that the controlling factor of the enhanced sediment transportation is not area-wide, but probably related to the activities of ephemeral river system.

  15. Controls on Organic Layer Combustion Severity During Wildfire in Boreal Bogs

    NASA Astrophysics Data System (ADS)

    Benscoter, B. W.; Thompson, D. K.; Waddington, J. M.; Flannigan, M. D.; Wotton, B. M.; de Groot, W. J.; Turetsky, M. R.

    2009-05-01

    Wildfires are the dominant natural disturbance to western Canadian peatlands, affecting an average of 1870 km2 annually and releasing 3.5 Tg of carbon (C) to the atmosphere through partial combustion of the extensive surface organic layer (peat) found therein. Combustion severity within fire-affected peatlands is variable, ranging from unburned islands and lightly burned "Sphagnum sheep" to deeply charred areas with >10 cm of surface fuel combustion. Spatial heterogeneity in combustion may be due to variation in moss community composition and corresponding variability in fuel condition due to interspecific differences in water retention ability and peat bulk density. However, the controls on surface organic layer combustion severity are poorly understood. We conducted a laboratory combustion experiment to examine the influence of peat type and soil moisture on the occurrence and depth of peat consumption. The soil moisture profiles of replicate monoliths of the three prevalent western Canadian bog peat types (Sphagnum fuscum hummocks, Pleurozium schreberi hummocks, and multi-species hollows) were manipulated to simulate field, moderately dry, and severe drought moisture conditions. Following manipulation and assessment of initial fuel conditions (bulk density, soil moisture, and surface topography), the monoliths were instrumented with soil moisture (TDR) probes and thermocouples and exposed to a constant radiative heat source, monitoring changes in soil moisture, temperature, and surface elevation from ignition to the extinction of combustion. We found bulk density and soil moisture interactively influenced depth of combustion through controls on peat thermal properties. Stratigraphic variation in bulk density and soil moisture created barriers to the downward propagation of combustion, which varied within and among monoliths. From these results, we developed a one-dimensional heat transfer model capable of predicting the depth of peat consumption based on peat bulk density and soil moisture stratigraphy. This model provides a framework for assessing current and future vulnerability of the peat organic layer to combustion losses during wildfire.

  16. Variations of 18O/ 16O in plants from temperate peat bogs (Switzerland): implications for paleoclimatic studies

    NASA Astrophysics Data System (ADS)

    Ménot-Combes, Guillemette; Burns, Stephen J.; Leuenberger, Markus

    2002-09-01

    Despite the great potential of peat bogs as climatic archives, to date only few studies have focused on the climatic controls on cellulose isotopic composition in modern bog plants. This study attempts to calibrate plant-climate relationships by sampling a set of modern plant species (both vascular plants and mosses) and bog surface waters along an altitude transect in Switzerland. Isotopic analyses of water samples show that the ? 18O-values of surface bog waters follow the trend of precipitation despite significant scatter in the data set. Detailed sampling of surface waters within one bog shows that ? 18O-values vary widely and are closely related to the micro-topography of the bog surface. More enriched 18O/ 16O ratios in water samples collected from small raised hummocks than the ones collected from hollows are documented in both horizontal and vertical profiles. A ? 18O-?D plot indicates that the process leading to the isotopic enrichment of the uppermost surface waters is evaporation, greater above Sphagnum covered hummocks than above open pools. To investigate the implications of such high variability of source water for plant ?-cellulose ? 18O-values, a detailed study of both surface water and ?-cellulose ? 18O-values within one site is conducted. The large ? 18O variability observed in surface waters is found to be considerably smoothed in ?-cellulose (by a factor of 5-10 depending on the plant species). This indicates that the water used by plant photosynthetic processes reflects the isotopic composition of the average annual precipitation. This points to a source water level for plants of a few decimeters where the variations are smaller than at the air-water interface. The response of the ?-cellulose ? 18O to the environmental gradient along the altitude transect varies considerably from species to species. For most of the species studied, the ? 18O-values decrease with altitude, following the trends of ? 18O-values in precipitation and in surface water samples. Some species, the cotton sedge Eriophorum vaginatum and the moss Sphagnum capillifolium, show statistically significant ? 18O relationships to an altitude of -1.8‰/km and -2.9‰/km respectively. However, some other plant species, Calluna vulgaris, Vaccinium uliginosum, Andromeda poliflora, Carex pauciflora, Sphagnum cuspidatum and Sphagnum magellanicum, do not, or only partially, reflect changes in climatic parameters associated with an altitude increase. Furthermore, changes in relative humidity, which are not correlated with altitude, are found to explain a large part of the variability in ? 18O-values for the sedge Carex pauciflora and the moss Sphagnum cuspidatum. Therefore, this study confirms the importance of species-specific studies when interpreting 18O/ 16O ratios of macrofossils along a fossil peat sequence as a record of past climate changes. Our study allows to extend the mechanistic model that isotopically links source water and cellulose to the physiological specificities of sedges and mosses. A comparison of the modeled and calculated net biological fractionation factors for Eriophorum vaginatum and Sphagnum capillifolium reveals that these two species appear to have a more homogeneous leaf reservoir than trees.

  17. Physiological and morphological effects of long-term ammonium or nitrate deposition on the green and red (shade and open grown) Sphagnum capillifolium

    Microsoft Academic Search

    S. Manninen; C. Woods; I. D. Leith; L. J. Sheppard

    2011-01-01

    Sphagna are vulnerable to enhanced nitrogen (N) deposition. This article reports how the green (shade, under Calluna) and red (open grown) Sphagnum capillifolium respond to ammonium and nitrate additions of 56kg Nha?1y?1 over the background of 8–10kg Nha?1y?1 on an ombrotrophic bog in the Scottish Borders after seven years. Samples and measurements were made during a range of hydrated and

  18. Lipid D\\/H Ratios from Multiple Sources and Deposits Indicate Drier Little Ice Age at Washington Island (4°43`N, 160°25`W), Central Pacific

    Microsoft Academic Search

    I. Muegler; D. Sachse; J. P. Sachs

    2010-01-01

    To compare the sensitivity of biomarker D\\/H ratios from two distinct climate archives, a lake and a peat bog on the Tropical Pacific Island of Terrania, compound-specific hydrogen isotope ratios (expressed as deltaD values) were determined on lipid biomarkers from various biological sources deposited in the two climate archives. At present, Terrania or Washington Island (4°43`N, 160°25`W) permanently lies in

  19. Postfire carbon balance in boreal bogs of Alberta, Canada R . K E L M A N W I E D E R *, K I M B E R L I D . S C O T T *, K AT H E R I N E K A M M I N G A *, M E L A N I E A .

    E-print Network

    Benscoter, Brian W.

    Postfire carbon balance in boreal bogs of Alberta, Canada R . K E L M A N W I E D E R *, K I M B E region near Wabasca, AB, Canada, where ombrotrophic Sphagnum-dominated bogs cover 2280 km2 that burn of 10 bog sites, spanning 1­102 years-since-fire (in 2002). Immediately after fire, bogs represent a net

  20. Modeling CH4 and CO2 cycling using porewater stable isotopes in a thermokarst bog, interior Alaska

    NASA Astrophysics Data System (ADS)

    Neumann, R. B.; Blazewicz, S.; Waldrop, M. P.

    2014-12-01

    Methane emitted from wetlands represents the end product of various microbial processes operating within anaerobic wetland soils. Determining the rate at which these microbial reactions occur is challenging, making it difficult to gain a mechanistic understanding of the factors and conditions that influence microbial rates and ultimately methane emissions. One approach for estimating in-situ reaction rates involves tracking the time evolution of porewater concentrations and stable carbon isotopes of CH4 and CO2. Microbes preferentially use isotopically light carbon substrates, which causes the carbon product pool to become isotopically lighter and the carbon substrate pool become isotopically heavier. Different microbial biochemical pathways fractionate carbon to different extents, allowing for differentiation between microbial reactions. This is a powerful approach to estimate in-situ rates, but, as we show in our presentation, it is possible for different combinations of reaction rates to provide equally good fits to the evolution of these data. The solution is non-unique and depends on the set of considered reactions. We used two different reaction network models on a set of porewater data collected from a thermokarst bog at the Alaska Peatland Experiment (APEX) outside of Fairbanks, AK to estimate in-situ microbial reaction rates during the summer season. Both models included methane production, methane oxidation and fermentation/respiration, but only one model included homoacetogenesis. We found that both reaction networks explained the evolution of dissolved gas concentrations and stable carbon isotope data, but predicted rates that differed from each other by up to a factor of six. The methane production rates estimated by the model that included homoacetogenesis aligned better with measured rates of methane emission. Despite differences in the magnitude of modeled rates, results from the two models told a similar story about the spatial and temporal patterns of microbial rates at the site. Modeled rates were higher at the edge of the bog than in the center of the bog, and rates at the edge increased during the summer while those in the center did not change with time. In both the center and at the edge of the bog, modeled rates increased with depth. We present hypotheses for these patterns.

  1. Amyloid deposits

    PubMed Central

    Treusch, Sebastian; Cyr, Douglas M.; Lindquist, Susan

    2015-01-01

    Neurodegenerative diseases ranging from Alzheimer disease and polyglutamine diseases to transmissible spongiform encephalopathies are associated with the aggregation and accumulation of misfolded proteins. In several cases the intracellular and extracellular protein deposits contain a fibrillar protein species called amyloid. However while amyloid deposits are hallmarks of numerous neurodegenerative diseases, their actual role in disease progression remains unclear. Especially perplexing is the often poor correlation between these deposits and other markers of neurodegeneration. As a result the question remains whether amyloid deposits are the disease-causing species, the consequence of cellular disease pathology or even the result of a protective cellular response to misfolded protein species. Here we highlight studies that suggest that accumulation and sequestration of misfolded protein in amyloid inclusion bodies and plaques can serve a protective function. Furthermore, we discuss how exceeding the cellular capacity for protective deposition of misfolded proteins may contribute to the formation of toxic protein species. PMID:19411847

  2. Multiproxy Record of Late Pleistocene-Holocene Climate and Vegetation Changes from a Peat Bog in Patagonia

    NASA Astrophysics Data System (ADS)

    Pendall, Elise; Markgraf, Vera; White, James W. C.; Dreier, Mark; Kenny, Ray

    2001-03-01

    Pollen assemblage changes and stable hydrogen isotope analysis of mosses (Sphagnum magellanicum and Drepanocladus s.l.) from a bog in Tierra del Fuego, Argentina, provided independent proxies for reconstructing changes in effective moisture and temperature over the past 16,000 cal yr B.P. A deterministic model was used to reconstruct the stable hydrogen isotope composition of meteoric water from the D/H ratios of bog mosses over the last 16,000 years. Abrupt changes in temperature, as recorded in D/H ratios of moss cellulose, were accompanied by synchronous changes in vegetation composition during the late Pleistocene and early and middle Holocene, when moisture levels were lower than today. In contrast, temperature variability during the late Holocene was not accompanied by comparable vegetation changes. In particular, grass pollen (Poaceae) increased during periodic cold spells between 15,000 and 11,000 cal yr B.P., but a cold spell of similar magnitude ca. 2000 cal yr B.P. did not appear to affect vegetation. During the late Pleistocene, the isotopic record from the peat core shows variations similar to the D/H ratios in the Antarctic Taylor Dome ice core. However, the timing of the changes in the Harberton record is more in line with the timing of other Southern Hemisphere records.

  3. Carbon and Nitrogen Isotope Variation in Sphagnum from Peat Bogs in the Midwestern Us: Implications for Holocene Climate Reconstruction

    NASA Astrophysics Data System (ADS)

    Wong, D.; Paytan, A.; Jackson, S. T.

    2009-12-01

    A peat core taken from near the center of Minden Bog in Michigan, representing about 3500 years of accumulation was previously analyzed for plant macrofossils, colorimetric humification, and testate amoebae to yield three independent climate proxies. The data show the site to be sensitive to bog water table fluctuations and suggest that this may be related to regional climatic changes. We analyzed the carbon and nitrogen isotopes and the carbon-nitrogen ratios in the bulk peat samples and determined that the changes in these isotopes and ratios can be attributed to one or more of the following: (1) changes in the relative abundance of vegetation taxa in the site, (2) changes in the metabolism that impact isotope ratios in the vegetation contributing to the bulk organic, and (3) selective preservation and regeneration of specific organic compounds within the bulk organic matter. We analyzed the carbon and nitrogen isotopes and the carbon-nitrogen ratios in a specific taxum, Sphagnum, to differentiate between these mechanisms and relate the record to water level and climate in the region.

  4. Biogeochemical indicators of peatland degradation - a case study of a temperate bog in northern Germany

    NASA Astrophysics Data System (ADS)

    Krüger, J. P.; Leifeld, J.; Glatzel, S.; Szidat, S.; Alewell, C.

    2014-12-01

    Peatlands store a great proportion of the global soil carbon pool and can loose carbon via the atmosphere due to degradation. In Germany, most of the greenhouse gas emissions from organic soils are attributed to sites managed as grassland. Here we investigated a land-use gradient from near-natural wetland (NW) to an extensively managed (GE) to an intensively managed grassland site (GI), all formed in the same bog complex in northern Germany. Vertical depth profiles of ?13C, ?15N, ash content, C/N ratio, bulk density, as well as radiocarbon ages were studied to identify peat degradation and to calculate carbon loss. At all sites, including the near-natural site, ?13C depth profiles indicate aerobic decomposition in the upper horizons. Depth profiles of ?15Ndiffered significantly between sites with increasing ?15N values in the top layers with increasing intensity of use, indicating that the peat is more decomposed. At both grassland sites, the ash content peaked within the first centimeter. In the near-natural site, ash contents were highest in 10-60 cm depth. This indicates that not only the managed grasslands, but also the near-natural site, is influenced by anthropogenic activities, most likely due to the drainage of the surrounding area. However, we found very young peat material in the first centimeter of the NW, indicating recent peat growth. The NW site accumulates carbon today even though it is and probably was influenced by anthropogenic activities in the past indicated by ?13C and ash content depth profiles. Based on the enrichment of ash content and changes in bulk density, we calculated carbon loss from these sites in retrograde. As expected land use intensification leads to a higher carbon loss which is supported by the higher peat ages at the intensive managed grassland site. All investigated biogeochemical parameters together indicate degradation of peat due to (i) conversion to grassland, (ii) historical drainage as well as recent development and (iii) land use intensification.

  5. A 5 Year Study of Carbon Fluxes from a Restored English Blanket Bog

    NASA Astrophysics Data System (ADS)

    Worrall, F.; Dixon, S.; Evans, M.

    2014-12-01

    This study aimed to measure the effects of ecological restoration on blanket peat water table depths, DOC concentrations and CO2 fluxes. In April 2003 the Bleaklow Plateau, an extensive area of deep blanket peat in the Peak District National Park, northern England, was devegetated by a wildfire. As a result the area was selected for large scale restoration. In this study we considered a 5-year study of four restored sites in comparison to both an unrestored, bare peat control and to vegetated control that did not require restoration. Results suggested that sites with revegetation alongside slope stabilisation had the highest rates of photosynthesis and were the largest net (daylight hours) sinks of CO2. Bare sites were the largest net sources of CO2 and had the deepest water table depths. Sites with gully wall stabilisation were between 5-8 times more likely to be net CO2 sinks than the bare sites. Revegetation without gully flow blocking using plastic dams did not have a large effect on water table depths in and around the gullies investigated whereas a blocked gully had water table depths comparable to a naturally revegetating gully. A ten centimetre lowering in water table depth decreased the probability of observing a net CO2 sink, on a given site, by up to 30%. With respect to DOC the study showed that the average soil porewater DOC concentration on the restored sites rose significantly over the 5 year study representing a 34% increase relative to the vegetated control and an 11% increase relative to the unrestored, bare control. Soil pore water concentrations were not significantly different from surface runoff DOC concentrations and therefore restoration as conducted by this study would have contributed to water quality deterioration in the catchment. The most important conclusion of this research was that restoration interventions were apparently effective at increasing the likelihood of net CO2 sink behaviour and raising water tables on degraded, climatically marginal blanket bog. However, had water table restoration been conducted alongside revegetation then a significant decline in DOC concentrations could have also been realised.

  6. Evidence for Multiple Holocene Marine Impact Events: Ejecta in a Bog Core

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Courty, M.; Breger, D.; Costa, S.; Gerard-Little, P.; Burckle, L.; Pekar, S.

    2006-12-01

    In a core from Tamarack Pond (a former bog) in the Hudson Highlands of New York, we found two layers containing marine microfossils. Because carbon rich sediments can be bioturbated over 20 cm depths, we give the layer thicknesses as 20 cm. The first layer is at 332-354 cm depth. It contains a radiolarian with a splashed on coating of Fe-Cr-Ni metal. It also contains a benthonic foraminiferal fossil. The second layer is at 432-454 cm depth. The second layer contains a degraded radiolarian fossil, a silicate with a splashed on coating of Fe-Cr-Ni metal, a carbon rich spherule containing Fe-Cr-Ni metal, and a grain of titanomagnetite with multiple craters. It also contains organic matter with Sn in it. As Tamarack Pond is quite far from the ocean, the marine fossils in the cores are unlikely to be windblown debris of Holocene age. A benthonic foraminifera is particularly unlikely to be blown by the wind. This conclusion is strengthened by the observation that the splashed on coating of Fe-Cr-Ni metal occurs in chondritic relative abundances with Fe>Cr>Ni. In grains with a thick layer of splashed metal, the Ni is sufficiently abundant to produce 3 distinct Ni peaks in the X-ray analysis. Such a high abundance of Ni coupled with chondritic relative abundances suggests that the Fe-Cr- Ni splash is derived from the vaporization of an extraterrestrial impactor. If we assume that the sedimentation rate of the Tamarack Pond core is the same as that of a previously dated core from nearby Sutherland Pond, the two layers have an uncorrected C-14 age of around 900-1200 B.C. for the layer at 332-354 cm and 2100 to 2400 B.C. for the layer at 432-454 cm. Both ages have a rough correspondence with times of climate downturn recorded in tree ring data (1159 and 2354 B.C.). These climate downturns cannot be explained by volcanic eruptions and are proposed to be cosmogenic in origin[1]. The older layer also corresponds in components to a previously studied circa 2350 B.C. impact ejecta layer[2]. [1]. Baillie, M., 1999, Exodus to Arthur: Catastrophic Encounters with Comets: London, UK, B. T. Batsford, 272 p. [2]. Courty, M.-A. et al. , 2006, Geoph. Res. Abs., vol. 8, A-01812.

  7. Effect of trap color and height on captures of blunt-nosed and sharp-nosed leafhoppers (hemiptera: cicadellidae) and non-target arthropods in cranberry bogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of field experiments were conducted in cranberry bogs in 2006-2010 to determine adult attraction of the two most economically important leafhopper pests of cultivated Vaccinium spp. in the northeast USA, the blunt-nosed leafhopper, Limotettix vaccinii, and sharp-nosed leafhopper, Scaphytopi...

  8. Cation-exchange capacity and galacturonic acid content of several species of sphagnum in Sandy Ridge Bog, central New York State

    Microsoft Academic Search

    Ann M. Spearing

    1972-01-01

    A very high correlation between the cation-exchange capacity and the content of galacturonic acid was found in eight species of sphagnum from Sandy Ridge Bog, in central New York State. An equally high correlation exists between the cation-exchange capacity and the optimum elevation for growth, measured in height above the water table.

  9. Chemical composition, pH, and redox state of sulfur and iron in complete vertical porewater profiles from two Sphagnum peat bogs, Jura Mountains, Switzerland

    Microsoft Academic Search

    Philipp Steinmann; William Shotyk

    1997-01-01

    Complete porewater profiles from two peat bogs in the Jura Mountains were analysed for major and trace inorganic anions and cations. At La Tourbière des Genevez (TGe) and Etang de la Gruère (EGr), peat formation began approximately 5,000 and 10,000 years bp, respectively. The maximum depths of peat accumulation are 140 cm (TGe) and 650 cm (EGr); previous geochemical studies

  10. Evolution of organic matter indicators in response to major environmental changes: The case of a formerly cut-over peat bog (Le Russey, Jura Mountains, France)

    E-print Network

    Paris-Sud XI, Université de

    of a formerly cut-over peat bog (Le Russey, Jura Mountains, France) Laure Comont, Fatima Laggoun-Défarge, Jean To assess whether the biochemical characteristics of peat can provide clues for past ecosystem changes monosaccharide determination of peat organic matter (OM) and the dominant living plants from a formerly cut

  11. Dinitrogen (C 2 H 2 ) fixation in relation to nitrogen fertilization of grey alder [ Alnus incana (L.) Moench.] plantations in a peat bog

    Microsoft Academic Search

    L. Rytter; A. S. Arveby; U. Granhall

    1991-01-01

    Nitrogenase activity was measured in young grey alder plantations in a peat bog in central Sweden. The stands were treated in three ways: (1) daily irrigation during the growing season with a complete nutrient solution, including N; (2) application of bark ash or wood ash before planting; and (3) fertilization every second year with solid PK fertilizers. Acetylene reduction assays

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

    NASA Astrophysics Data System (ADS)

    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 diversity of methanotrophs in different Sphagnum dominated bog microhabitats. In contrast to the Northern Hemisphere peat ecosystems the temperate South American peat bogs are dominated by one moss species; Sphagnum magellanicum. This permitted a species-independent comparison of the different bog microhabitats. Potential methane oxidizing activity was found in all Sphagnum mosses sampled and a positive correlation was found between activity and in situ methane concentrations. Substantial methane oxidation activity (23 ?mol CH4 gDW-1 day-1) was found in pool mosses and could be correlated with higher in situ methane concentrations (>35 ?mol CH4 l-1 pore water). Little methanotrophic activity (<0.5 ?mol CH4 gDW-1 day-1) was observed in living Sphagnum mosses from lawns and hummocks. Methane oxidation activity was relatively high (>4 ?mol CH4 gDW-1 day-1) in Sphagnum litter at depths around the water levels and rich in methane. The total bacterial community was studied using 16S rRNA gene sequencing and the methanotrophic communities were studied using a pmoA microarray and a complementary pmoA clone library. The methanotrophic diversity was similar in the different habitats of this study and comparable to the methanotrophic diversity found in peat mosses from the Northern Hemisphere. The pmoA microarray data indicated that both alpha- and gammaproteobacterial methanotrophs were present in all Sphagnum mosses, even in those mosses with a low initial methane oxidation activity. Prolonged incubation of Sphagnum mosses from lawn and hummock with methane revealed that the methanotrophic community present was viable and showed an increased activity within 15 days. The high abundance of methanotrophic Methylocystis species in the most active mosses suggests that these might be responsible for the bulk of methane oxidation.

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

    NASA Astrophysics Data System (ADS)

    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

    2011-09-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methanotrophs living in and 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 diversity of methanotrophs in different Sphagnum dominated bog microhabitats. In contrast to the Northern Hemisphere peat ecosystems the temperate South American peat bogs are dominated by one moss species; Sphagnum magellanicum. This permitted a species-independent comparison of the different bog microhabitats. Potential methane oxidizing activity was found in all Sphagnum mosses sampled and a positive correlation was found between activity and in situ methane concentrations. Substantial methane oxidation activity (23 ?mol CH4 gDW-1 day-1) was found in pool mosses and could be correlated with higher in situ methane concentrations (>35 ?mol CH4 l-1 pore water). Little methanotrophic activity (<0.5 ?mol CH4 gDW-1 day-1) was observed in living Sphagnum mosses from lawns and hummocks. Methane oxidation activity was relatively high (>4 ?mol CH4 gDW-1 day-1) in Sphagnum litter situated at depths around the water levels and rich in methane. The total bacterial community was studied using 16S rRNA gene sequencing and the methanotrophic communities were studied using a pmoA microarray and a complementary pmoA clone library. The methanotrophic diversity was similar in the different habitats of this study and surprisingly comparable to the methanotrophic diversity found in peat mosses from the Northern Hemisphere. The pmoA microarray data indicated that both alpha- and gammaproteobacterial methanotrophs were present in all Sphagnum mosses, even in those mosses with a low initial methane oxidation activity. Prolonged incubation of Sphagnum mosses from lawn and hummock with methane revealed that the methanotrophic community present was viable and showed an increased activity within 15 days. The high abundance of methanotrophic Methylocystis species in the most active mosses suggests that these might be responsible for the bulk of methane oxidation.

  14. Deposition Equipment

    NSDL National Science Digital Library

    This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. Use this module to develop your learners' ability to control deposition equipment operations. The activities are adaptable to cleanroom or laboratory, and employ the Applied Materials Precision 5000 as a prototypical CVD tool. The module takes learners through a review of the deposition process, an introduction to the systems and subsystems of a CVD tool, and through an entire operations cycle from recipe interpretation through process control of inputs/outputs.

  15. CH4 production via CO2 reduction in a temperate bog - A source of (C-13)-depleted CH4

    NASA Technical Reports Server (NTRS)

    Lansdown, J. M.; Quay, P. D.; King, S. L.

    1992-01-01

    The paper reports measurements, taken over two annual cycles, of the flux and delta(C-13) of CH4 released from an acidic peat bog located in the foothills of the Cascade Range in Washington state, U.S. Measurements of the rate of aceticlastic methanogenesis and CO2 reduction in peat soil, using (C-14)-labeled acetate and sodium bicarbonate, show that acetate was not an important CH4 precursor and that CO2 reduction could account for all of the CH4 production. The in situ kinetic isotope effect for CO2 reduction, calculated using the delta-(C-13) of soil water CO2 and CH4 flux, was 0.932 +/- 0.007.

  16. The spatial and temporal relationships between CO2 and CH4 exchange in a temperate ombrotrophic bog

    NASA Astrophysics Data System (ADS)

    Lai, Derrick Y. F.; Roulet, Nigel T.; Moore, Tim R.

    2014-06-01

    We investigate the relationships between CO2 and CH4 fluxes across space and time at a temperate ombrotrophic bog in Canada to assess the coupling between plant production and CH4 emissions. Based on periodic manual chamber measurements, we show that maximum net ecosystem CO2 exchange (NEEmax) was a good predictor of the spatial variations in CH4 flux among the wetter Eriophorum and lawn sites (r2 = 0.61-0.88), but not the drier hummock sites (r2 = 0.04-0.49). Also, we observed large interannual variability in the NEEmax-CH4 relationship at the Eriophorum and lawn sites, with a smaller regression slope in 2010 that had a seasonal mean water table 8 cm lower than in 2009. Results of cross-correlation of instantaneous gross ecosystem production (GEP) and CH4 flux from autochambers show a moderate relationship (? = -0.31) in the Eriophorum community at a lag of 9-12 h, suggesting a rapid turnover of recent photosynthate for methanogenesis. On the other hand, we found in two Maianthemum-dominated chambers that the temperature-independent residuals of daily mean CH4 flux lagged behind GEP by 18-26 days at the seasonal scale. The lagged correlations between GEP and CH4 flux by month were particularly strong in the late growing season in the Eriophorum and Maianthemum/Ledum communities. Our results suggest the presence of spatial and temporal coupling of plant production and CH4 emissions in this bog, whose strength varies with species composition, water table position, and plant phenology.

  17. Peat bogs offer a reliable, local source of fuel in several states

    SciTech Connect

    Punwani, D.V.

    1981-10-01

    With total estimated US peat resources equivalent to the energy content of 240-billion bbl of oil, peat could be a significant energy resource even if only a fraction of it can be recovered. Resource estimates include only those areas (mostly in eight states) with at least 80 acres/sq mi of peat, where the deposits are at least 4 ft deep. Peat fuel properties, new equipment for peat harvesting and dewatering, and modern combustion technology are described. Conversion to synthetic fuels looks promising.

  18. Control of carbon mineralization to CH 4 and CO 2 in anaerobic, Sphagnum -derived peat from Big Run Bog, West Virginia

    Microsoft Academic Search

    Joseph B. Yavitt; Gerald E. Lang; R. Kelman Wieder

    1987-01-01

    The mineralization of organic carbon to CH4 and CO2 inSphagnum-derived peat from Big Run Bog, West Virginia, was measured at 4 times in the year (February, May, September, and November) using anaerobic, peat-slurry incubations. Rates of both CH4 production and CO2 production changed seasonally in surface peat (0–25 cm depth), but were the same on each collection date in deep

  19. Carbohydrate polymers in food preservation: an integrated view of the Maillard reaction with special reference to discoveries of preserved foods in Sphagnum-dominated peat bogs

    Microsoft Academic Search

    Terence J Painter

    1998-01-01

    Well-preserved human bodies more than 2000years old have been found in peat bogs derived mainly from sphagnum mosses. Preservation is correlated with the occurrence of ?-keto-carboxylate groups in a glycuronoglycan (`sphagnan') that comprises ?60% of the holocellulose in the hyaline cell walls of the mosses [Painter (1991b). Carbohydr. Polym., 15, 123–142]. There is now renewed interest in other biodegradable materials

  20. Micropaleontological observations on a Sphagnum bog in East Carpathian region – testate amoebae (Rhizopoda: Testacea) and their potential use for reconstruction of micro- and macroclimatic changes

    Microsoft Academic Search

    Csaba Schnitchen; E Niký O Magyari; Béla Tóthmérész; István Grigorszky; Mihály Braun

    2003-01-01

    We investigated the possibilities of reconstructing the hydrological history of an East Carpathian Sphagnum bog (Fenyves-teto, near Erzsébetbánya) based on the Testacea fauna and the humification. A Russian-type sampler was used to supply undisturbed cores of 400 cm in depth. The exotic marker method (Lycopodium clavatum as a marker) was used for quantitative estimation of the abundances. Humic acid concentration was

  1. CH 4 production, oxidation and emission in a U.K. ombrotrophic peat bog: Influence of SO 4 2? from acid rain

    Microsoft Academic Search

    David B. Nedwell; Andrea Watson

    1995-01-01

    Factors influencing the rates of production and emission of CH4, CH4 oxidation and rates of SO42? reduction, were measured in the peat of an ombrotrophic bog in New Galloway, Scotland. Vertical concentration profiles of CH4 and O2 showed that the water table essentially represented the oxic-anoxic boundary in the peat. This boundary was usually at the surface in the case

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

    NASA Astrophysics Data System (ADS)

    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. The yearly GWP100 balances ranged from -280.5 ± 465.2 to 644.5 ± 413.6 g CO2-eq. m-2 a-1 at the rewetted sites. In contrast, the Sphagnum farming site had a cooling impact on the climate in both years (-356.8 ± 176.5 and -234.9 ± 145.9 g CO2-C m-2 a-1). If the exported carbon through the harvest of the Sphagnum biomass and the additional CO2 emission from the decay of the organic material is considered, the NECB and GWP100 balances are near neutral. Peat mining sites are likely to become net carbon sinks and a peat accumulating ("growing") peatland within 30 years after rewetting, but the GWP100 balance may still be positive. A recommended measure for rewetting is to achieve a water level of a few centimetres below ground surface. Sphagnum farming is a climate friendly alternative to conventional commercial use of bogs. A year round constant water level of a few centimetres below ground level should be maintained.

  3. 13C/Palynological evidence of differential residence times of organic carbon prior to its sedimentation in East African Rift Lakes and peat bogs

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, Claude; Aucour, Anne-Marie; Bonnefille, Raymonde; Riollet, Guy; Vincens, Annie; Williamson, David

    Most terrestrial plants producing large amounts of organic matter in the East African Rift follow the Calvin (C3) photosynthetic pathway. Their end products have ?13C values of ca. -27 ± 2‰ (vs. PDB). On the contrary, most Cyperaceae (notably Cyperus papyrus and C. latifolius) are characterized by higher 13C contents ° 13C = -10.5 ± 1‰ ) in relation to their Hatch and Slack (C4) photosynthetic cycle. In consequence, ?13C values in total organic matter (TOM) from peat bog or lake cores essentially responded to the proportion of detritus from C4-Cyperaceae. Immediate evidence of the development or disappearance of Cyperaceae around lake margins or in peat bogs can be found in pollen assemblages. Lag times between pollen signals and correlative ° 13C shifts in TOM from cores are therefore indicative of the residence time of organic matter prior to its sedimentation. Delayed sedimentation of TOM will result in 14C anomalies which depend on several parameters, most of them being site specific as shown by examples from a peat bog in Burundi and from southern Lake Tanganyika. An independent assessment of the chronology by high resolution paleomagnetic correlations indicates a ca. 1.5 ka apparent 14C age of TOM in Lake Tanganyika at the Pleistocene-Holocene transition.

  4. Reconstructing historical Pb and Hg pollution in NW Spain using multiple cores from the Chao de Lamoso bog (Xistral Mountains)

    NASA Astrophysics Data System (ADS)

    Martínez Cortizas, A.; Peiteado Varela, E.; Bindler, R.; Biester, H.; Cheburkin, A.

    2012-04-01

    We have applied a single-bog multi-core approach to reconstruct historical Pb and Hg accumulation in an ombrotrophic bog from NW Spain, Chao de Lamoso (Xistral Mountains). Mercury was determined using a LECO-ALTEC AMA-254 analyzer, Pb with an EMMA-XRF analyzer and stable lead isotopes (four cores) by Quadrupole ICP-MS. Maximum concentrations were 74-122 ?g g-1 for Pb and 142-300 ng g-1 for Hg. Higher variability was found for Hg than for Pb (2-3 times and 1.5 times, respectively). The slopes of the relationship between Hg and Pb cumulative inventories also suggested differences in relative accumulation of both elements. This substantial spatial variability indicates that, compared with Pb, a more extended sampling may be needed for an accurate estimation of Hg accumulation in mires. The isotopic records showed higher and almost constant 206Pb/207Pb ratios (average 1.174 ± 0.004) in the lower sections and a continuous decrease to the surface (minimum 1.141). By using the change in the isotopic composition of Pb we estimated a chronology for the last ˜200 years which enabled and approximation of the temporal trends in metal pollution. Based on the average isotopic composition of the studied cores and the application of a simple binary mixing model, six periods with increasing proportions of pollution Pb were identified: prior to ˜1875 AD, with an average proportion lower than 16%; ˜1875-1910 AD, increasing up to 24%; ˜1910-1950 AD, up to 35%; ˜1950-1970, up to 54%; ˜1970-1980 AD, up to 74%; and after ˜1980 AD, increasing up to 80%. The period with the highest rate of increase in recent (since ˜1900 AD) pollution Pb (equivalent to 2% year-1) seems to have started at the maximum in Pb accumulation around the early 1970s. The Hg records showed a more simple evolution with four main phases: prior to ˜1875 AD with enrichments around 1.5-fold the background, ˜1875-1955 AD with increasing enrichments; from ˜1955 AD to ˜1980 AD with maximum values (up to 4.2-fold); and from ˜1980 AD to present, with a steady decline to 2.4-fold. For the most recent period (after ˜1980 AD), the combination of decreasing Pb and Hg concentrations and accumulation rates/enrichments, and low 206Pb/207Pb ratios, may point to a higher relative importance of local sources (i.e. coal burning in a nearby power plant) in atmospheric metal pollution in the area.

  5. Age-dependent impacts of peatland restoration on the net ecosystem CO2 exchange of blanket bogs in Northern Scotland

    NASA Astrophysics Data System (ADS)

    Hambley, Graham; Hill, Timothy; Saunders, Matthew; Arn Teh, Yit

    2015-04-01

    The Flow Country of Northern Scotland is the largest area of contiguous blanket bog in the UK covering an area in excess of 400 km2. This region is the single largest peat and soil C repository in the UK, and plays a key role in mediating regional atmospheric exchanges of greenhouse gases (GHGs) such as carbon dioxide (CO2), methane (CH4) and water vapour (H2O). However, these peatlands were subject to significant afforestation in the 1980s, where large areas of blanket bog were drained and planted with Sitka spruce (Picea sitchensis) and Lodgepole Pine (Pinus contorta), resulting in modifications to micro-topographic features, vegetation composition and soil properties such as bulk density and water holding capacity, all of which are known to influence the production and emission of key GHGs. Since the late 1990s restoration work has been undertaken to remove forest plantations and to restore the peatland areas by raising the water table, predominantly by drain and furrow blocking, in order to encourage the recolonisation of Sphagnum species. Here we report findings from an eddy covariance study of CO2 and H2O exchange from an unmanaged peatland and a chronosequence of restored peatland sites, which were felled in 1998 and 2004. Located within the Forsinard Flows National Nature Reserve in Northern Scotland, these sites are being studied to better understand the key drivers of carbon dynamics in these ecosystems and also assess the age-dependent impacts of peatland restoration on the net CO2 sink strength. Preliminary data show rates of CO2 uptake increased with time since restoration, with peak assimilation rates of -9.9 and -14.4 micro mol CO2 m-2 s-1 measured at the 10 and 16 year old restoration sites, respectively. Carbon losses through ecosystem respiration followed a similar pattern. The data collected to date indicates that while peatland restoration is actively increasing CO2 uptake at each of the sites, more long-term observational data is required to produce robust carbon budgets and assess the vulnerability of these ecosystems to future climatic change.

  6. Carbon dioxide fluxes over a raised open bog at the Kinosheo Lake tower site during the Northern Wetlands Study (NOWES)

    NASA Technical Reports Server (NTRS)

    Neumann, H. H.; Den Hartog, G.; King, K. M.; Chipanshi, A. C.

    1994-01-01

    Measurements of carbon dioxide concentration and flux were made above a raised open bog at Lake Kinosheo in the southern Hudson Bay lowlands during the Northern Wetlands Study (NOWES) experiment in 1990. The flux measurements were made using micrometeorological techniques. They provide the first nondisturbing, larger-scale CO2 flux measurements for this ecosystem and are the first to integrate the exchange over the whole 24 hours of the day. Continuous concentration measurements by infrared gas analyzers (IRGA) and spot flask samples were taken over the period July 1 to July 29. Afternoon CO2 values were only 5 to 7 parts per million by volume (ppmv) lower than measurements over the same period at Canadian background monitoring stations. This suggested that there was little draw-down by local photosynthetic sinks. CO2 fluxes were measured at 8 and 18 m by Bowen ratio and eddy correlation methods, respectively. The methods produced comparable results on averaged data but often diverged considerably on individual half-hour results. Fluxes were small. Daytime values averaged to -0.068 mg/sq m/s by eddy correlation and -0.077 mg/sq m/s by Bowen ratio over the period June 25 to July 28 (negative denotes downward flux), while at night, flux densities were +0.062 mg/sq m/s and +0.085 mg/sq m/s. Integration of the mean diurnal curve gave a net flux of -1.7 g/sq m/d. Comparable data for this type of ecosystem were not found. However, Coyne and Kelley (1975), measuring near Barrow, Alaska, over wet meadow tundra dominated by sedges and grasses, found net fluxes of -7.2 g/sq m/d. Typical net CO2 fluxes from other active temperature ecosystems have been found to be -10 to -20 g/sq m/d (Monteith, 1976). Mean half hourly fluxes were almost constant at +0.06 mg/sq m/s through the nighttime hours. About one half-hour after sunrise the flux reversed direction. Uptake peaked about 0900 eastern daylight time (EDT) and then gradually declined but remained downward until near sunset. The early peak was interpreted to signify that the many plants in the bog experienced water stress during the day as evaporative demand increased and nighttime dew was evaporated.

  7. Atmospheric mercury deposition recorded in an ombrotrophic peat core from Xiaoxing'an Mountain, Northeast China

    SciTech Connect

    Tang, Shunlin, E-mail: tangshunlin@vip.gyig.ac.cn [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China) [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China); State Key laboratory of Geochemistry, Chinese Academy of Science, Guiyang (China); Huang, Zhongwei; Liu, Jun; Yang, Zaichan [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China)] [Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan province (China); Lin, Qinhua [State Key laboratory of Geochemistry, Chinese Academy of Science, Guiyang (China)] [State Key laboratory of Geochemistry, Chinese Academy of Science, Guiyang (China)

    2012-10-15

    The historical mercury accumulation rates (Hg AR) resulting from atmospheric deposition to Xiaoxing'an Mountain were determined via analysis of {sup 210}Pb- and {sup 14}C-dated cores up to 5000 years old. Natural Hg AR background, pre-industrial Hg AR and maximum industrial Hg AR in Northeast China were 2.2 {+-}1.0 {mu}g/m{sup 2}/yr for 5100-4500 BP, 5.7 {mu}g/m{sup 2}/yr and 112.4 {mu}g/m{sup 2}/yr, respectively. We assumed that the increase in Hg deposition in the Xiaoxing'an mountain area during industrial time was mainly attributed to local anthropogenic emissions around this peat bog.

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

    PubMed

    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. PMID:26002894

  9. Seasonality of atmospheric nitrogen deposition at a semi-natural peatland site

    NASA Astrophysics Data System (ADS)

    Hurkuck, M.; Brümmer, C.; Kutsch, W. L.

    2012-04-01

    Large areas of natural peat bogs in Northwestern Germany have been converted to arable land and are characterised by decades of draining and peat cutting. Our study site - a semi-natural raised bog - is one of only very few remaining protected peatland areas. However, it is surrounded by highly fertilized agricultural land and poultry farms. In this study, we use a combined approach of independent methods to quantify seasonal variations of atmospheric nitrogen deposition most likely originated from agricultural practices. Concentrations and fluxes of ammonia and its atmospheric reactants are measured by a KAPS-denuder system integrated over one-week periods. Additionally, total nitrogen input from the atmosphere into a soil-plant model ecosystem is investigated by a 15N dilution method called 'Integrated Total Nitrogen Input' (ITNI). With this approach, we aim to allocate atmospheric nitrogen after its uptake by the ecosystem in aboveground biomass, roots and soil. First results from April to November 2011 show average ammonia concentrations ranging from 0.9 to 13.0 ?g m-3. A first maximum of 8.8 ?g m-3 could be observed in spring followed by relatively stable concentrations (mean: 3.7 ?g m-3) in summer. Autumn ammonia concentrations reached a second peak of 13.0 ?g m-3. By now, winter concentrations tend to be lower than those during the rest of the measuring period. Using the KAPS-denuder system within a gradient setup, deposition of ammonia was found to be between 0.08 to 0.25 kg NH3-N ha-1 week-1. The proportion of concentrations and fluxes of other N compounds such as HNO3, aerosol NH4 and NO3 was usually around 20 % of total measured nitrogen. During the first months of investigation, we found a total dry N deposition of about 5.4 kg ha-1. Extrapolation of data to one year amounts approximately to 9 kg ha-1 yr1. Our results suggest that the intensive agricultural land management of surrounding areas most likely leads to increasing N input into the protected peatland area. The critical load for this nutrient-poor ecosystem might be exceeded and a future change in vegetation and hydrology is expected. Key words: nitrogen deposition, raised bog, 15N isotopes, KAPS denuder

  10. The effects of ecological restoration on CO2 fluxes from a climatically marginal upland blanket bog

    NASA Astrophysics Data System (ADS)

    Dixon, Simon; Qassim, Suzane; Rowson, James; Worrall, Fred; Evans, Martin

    2013-04-01

    A legacy of gully incision, deposition of industrially-derived aerial pollutants, inappropriate management and wildfire has left large expanses of the topographic Bleaklow Plateau (Peak District National Park, England, UK) bare of vegetation and susceptible to massive erosion of the peat soils. The consequence of such degradation has been to decrease the capacity of the peatland on the plateau to provide important ecosystem services including; loss of net C sink function, discolouration of surface waters, mobilisation to surface waters of stored heavy metals and infilling of upland reservoirs with peat-derived sediment. In response to on-going and worsening degradation a programme of ecological restoration has been undertaken. Restoration methods include: seeding with a lawn grass mix; liming; fertilisation; slope stabilisation; and gully blocking. This talk will present data from a five-year, observational-study of CO2 fluxes from eight sites, with four sites sampling different restoration treatments and four sampling bare and least disturbed areas. The results of the analysis reveal that sites with revegetation alongside slope stabilisation were most productive and were the largest net (daylight hours) sinks of CO2. Unrestored, bare sites, while having relatively low gross fluxes of CO2 were the largest net sources of CO2. Revegetation without slope stabilisation took longer (~18 months) to show an impact on CO2 flux in comparison to the sites with slope stabilisation. Binary logistic regression indicated that a ten centimetre increase in water table depth decreases the odds of observing a net CO2 sink, on a given site, by up to 30%. Sites with slope stabilisation were between 5-8x more likely to be net CO2 sinks than the bare sites. Sites without slope stabilisation were only 2-2.3x more likely to be net CO2 sinks compared to the bare sites. The most important conclusion of this research is that revegetation appears to be effective at increasing the likelihood of net CO2 behaviour on degraded, climatically marginal blanket peat, with revegetation alongside slope stabilisation having the greatest impact.

  11. Profiles of Water Content and Pore Size in Sphagnum and Peat, and their Relation to Peat Bog Ecology

    NASA Astrophysics Data System (ADS)

    Hayward, P. M.; Clymo, R. S.

    1982-06-01

    The bog mosses, Sphagnum, form a significant part of the total mass of plants in the world. Their rate of growth depends to a considerable extent on the supply of water to them, and different species occupy characteristic habitats which differ in their ability to supply water. We used the profiles of water content in almost undisturbed cores of two species to infer the size and distribution of spaces around the plants in an attempt to account for the observation that S. papillosum is usually found not far above the water table, while S. capilliforlium is usually found on hummocks well above the water table. Profiles of water content were recorded non-destructively from 30 cm diameter cores of Sphagnum and underlying peat, with use of the absorbance of the soft gamma radiation of 241Am. The distribution of water-fillable spaces of different size was inferred from profiles with the water table at different distances, to a maximum of 150 cm, below the surface. The larger spaces, which are the main path of water transport, are outside the plant cell walls: between leaves and between pendent branches and stems. The mean radius of such spaces around the hummock species S. capillifolium is smaller than that around S. papillosum. For a given depth of water table the water content of the apical tuft of branches, where growth occurs, is greater in the hummock species than it is in the lawn species. Of ecological importance is that, for a given water content in the apex, the water table is at a greater depth below the hummock species than it is below the lawn species. As the water table rises and falls, so the water content of both species shows hysteresis as large as the difference between them. The ecological significance of this and the need for measurements while water is flowing are discussed.

  12. Usual and unusual CIELAB color parameters for the study of peat organic matter properties: Tremoal do Pedrido bog (NW Spain)

    NASA Astrophysics Data System (ADS)

    Sanmartín, P.; Silva-Sánchez, N.; Martínez-Cortizas, A.; Prieto, B.

    2015-04-01

    We have tested the practical application of color measurements in the study of organic matter properties (C and N content, C/N ratios, degree of peat humification-DPH) of a 335 cm long peat core sampled at Tremoal do Pedrido bog. Usual and unusual CIELAB color parameters were measured on samples that were sectioned at high resolution (slices of 1 cm in thickness). The objective of the study is twofold: (i) describe a rapid, cost-effective and non-destructive method of assessing peat properties without the need of extractions and chemical methods and (ii) contribute to further research on applied colorimetry using the well-known CIELAB coordinates: L*, a*, b*, C*ab and hab (‘usual CIELAB color parameters’) and the less well-known CIELAB parameters: [a* x b*], [a*/b*], [(a*/b*) x 1000], [1000 x a*/(L*+ b*)], [2000 x a*/(L* x b*)] and RLab= [a*(a*2+b*2)1/2 1010]/(b* x L*6) (‘unusual CIELAB color parameters’). Our findings show that L* and hab coordinates as well as [(a*/b*) x 1000], [2000 x a*/(L* x b*)] and RLab parameters give the best bivariate Spearman's correlations. Linear regression equations were calculated to predict peat properties from all CIELAB parameters under study and a notable fit (R2: 0.65-0.79) was obtained. The evaluation presented here indicates that the determination of usual and unusual CIELAB parameters offers potential for the study of peat organic matter properties and encourages the routine application of this methodology on other peat cores and organic soils.

  13. The influence of past and present hydrological conditions on Sphagnum recolonization and succession in a block-cut bog, Québec

    NASA Astrophysics Data System (ADS)

    Price, Jonathan S.; Whitehead, Grant S.

    2004-02-01

    This study of an abandoned cutover bog aims to understand the processes controlling moisture conditions that have led to distinct spatial patterns of Sphagnum recolonization, and also how substrate conditions may have changed since abandonment and the implications for plant establishment. Two (unreplicated) symmetrical 12 × 3.5 m2 quadrats either side of the centre-line of a block-cut trench were treated by removing all recolonized vegetation, including Sphagnum, from one quadrat (REMOV), examining Sphagnum-covered (SPHAG) peat in the other, and bare peat (BARE) in both. Average volumetric soil moisture contents in the peat (2 cm below the surface) of the SPHAG and REMOV substrates were similar (86%), but greater than in BARE peat (78%). In a location not manipulated for this experiment, where Sphagnum cushions have re-established on bare cutover peat, beneath the cushions was 5-14% greater than in bare cutover peat directly adjacent to it, indicating that cushions can regulate local substrate water storage, and benefit from it during periods of increased water demand. This may have assisted in the lateral expansion of Sphagnum. A loosely structured 0.5 to 1.0 cm thick organic litter layer (chiefly Ericaceae) overlying the BARE peat substrate slowed the rate of drying of bare peat in a laboratory sample. The laboratory tests found the capillary fringe to be up to 26 cm above the water table. The dry conditions and the larger pore structure of this litter layer hindered upward capillary flow and, therefore, plant water availability. In (occluded) ditches and low areas, the capillary fringe remained within 5 cm of the surface, and these locations supported the most complete Sphagnum cover. In slightly higher areas, where the capillary fringe was about 20 cm below the surface, and because of the leaf litter, capillary water supply to the surface is sufficiently restricted to limit Sphagnum recolonization. These locations may have to await lateral expansion of Sphagnum cushions to achieve a full cover.

  14. Ecophysiological adaptations of anaerobic bacteria to low pH: analysis of anaerobic digestion in acidic bog sediments. [Lactobacillus; Clostridium; Sarcina ventriculi

    SciTech Connect

    Goodwin, S.; Zeikus, G.J.

    1987-01-01

    The dynamics of anaerobic digestion were examined in the low-pH sediments of Crystal Bog in Wisconsin. The sediments (pH 4.9) contained 71% organic matter and the following concentrations of dissolved gases (micromoles per liter):CO/sub 2/, 1140; CH/sub 4/, 490; and H/sub 2/, 0.01. The rate of methane production was 6.2 ..mu..mol/liter of sediment per h, which is slower than eutrophic, neutral sediments. Microbial metabolic processes displayed the following pH optima: hydrolysis reactions, between 4.2 and 5.6; aceticlastic methanogenesis, 5.2; and hydrogen-consuming reactions, 5.6. The turnover rate constants for key intermediary metabolites were (h/sup -1/): glucose, 1.10; lactate, 0.277; acetate, 0.118; and ethanol, 0.089. The populations of anaerobes were low, with hydrolytic groups (10/sup 6//ml) several orders of magnitude higher than methanogens (10/sup 2//ml). The addition of carbon electron donors to the sediment resulted in the accumulation of hydrogen, whereas the addition of hydrogen resulted in the accumulation of fatty acids and the inhibition of hydrogen-producing acetogenic reactions. Strains of Lactobacillus, Clostridium, and Sarcina ventriculi were isolated from the bog, and their physiological attributes were characterized in relation to hydrolytic process functions in the sediments. The present studies provide evidence that the pH present in the bog sediments alter anaerobic digestion processes s, that total biocatalytic activity is lower bu the general carbon and electron flow pathways are similar to those of neutral anoxic sediments.

  15. Dom Export from Coastal Temperate Bog Forest Watersheds to Marine Ecosystems: Improving Understanding of Watershed Processes and Terrestrial-Marine Linkages on the Central Coast of British Columbia

    NASA Astrophysics Data System (ADS)

    Oliver, A. A.; Giesbrecht, I.; Tank, S. E.; Hunt, B. P.; Lertzman, K. P.

    2014-12-01

    The coastal temperate bog forests of British Columbia, Canada, export high amounts of dissolved organic matter (DOM) relative to the global average. Little is known about the factors influencing the quantity and quality of DOM exported from these forests or the role of this terrestrially-derived DOM in near-shore marine ecosystems. The objectives of this study are to better understand patterns and controls of DOM being exported from bog forest watersheds and its potential role in near-shore marine ecosystems. In 2013, the Kwakshua Watershed Ecosystems Study at Hakai Beach Institute (Calvert Island, BC) began year-round routine collection and analysis of DOM, nutrients, and environmental variables (e.g. conductivity, pH, temperature, dissolved oxygen) of freshwater grab samples from the outlets of seven watersheds draining directly to the ocean, as well as near-shore marine samples adjacent to freshwater outflows. Dissolved organic carbon (DOC) varied across watersheds (mean= 11.45 mg L-1, sd± 4.22) and fluctuated synchronously with seasons and storm events. In general, higher DOC was associated with lower specific UV absorbance (SUVA254; mean= 4.59 L mg-1 m-1, sd± 0.55). The relationship between DOC and SUVA254 differed between watersheds, suggesting exports in DOM are regulated by individual watershed attributes (e.g. landscape classification, flow paths) as well as precipitation. We are using LiDAR and other remote sensing data to examine watershed controls on DOC export. At near-shore marine sites, coupled CTD (Conductivity Temperature Depth) and optical measures (e.g. spectral slopes, slope ratios (SR), EEMs), showed a clear freshwater DOM signature within the system following rainfall events. Ongoing work will explore the relationship between bog forest watershed attributes and DOM flux and composition, with implications for further studies on biogeochemical cycling, carbon budgets, marine food webs, and climate change.

  16. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

    PubMed

    Millett, J; Foot, G W; Svensson, B M

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. PMID:25655989

  17. Heathland vegetation as a bio-monitor for nitrogen deposition and source attribution using ?15N values

    NASA Astrophysics Data System (ADS)

    Skinner, R. A.; Ineson, P.; Jones, H.; Sleep, D.; Leith, I. D.; Sheppard, L. J.

    The %N and ?15N signals in foliar nitrogen (N) from four heathland species have been monitored in a blanket bog plant community subjected to different experimental inputs of wet and dry N deposition. Interactions with combined additional treatments of phosphorus (P) and potassium (K) were also investigated. Calluna vulgaris, Cladonia portentosa, Sphagnum capillifolium and Hypnum cupressiforme were harvested for 15N analysis prior to wet and dry treatment applications and again after 16 months field exposure. A significant increase was observed in both %N and ?15N values for all plant species in response to both wet and dry treatments whilst PK additions also produced significant decreases in foliar %N and associated ?15N values for several of the species sampled. These enrichments in the ?15N signals for post-treatment shoot tissue were attributable to the ?15N signal in the source application, a finding of potential value in using bio-monitors for assessment of N deposition.

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

    PubMed

    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. PMID:18043652

  19. Groundwater flow with energy transport and water-ice phase change: Numerical simulations, benchmarks, and application to freezing in peat bogs

    USGS Publications Warehouse

    McKenzie, J.M.; Voss, C.I.; Siegel, D.I.

    2007-01-01

    In northern peatlands, subsurface ice formation is an important process that can control heat transport, groundwater flow, and biological activity. Temperature was measured over one and a half years in a vertical profile in the Red Lake Bog, Minnesota. To successfully simulate the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified. The modified code simulates fully saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes proportional heat capacity and thermal conductivity of water and ice, decreasing matrix permeability due to ice formation, and latent heat. The model is verified by correctly simulating the Lunardini analytical solution for ice formation in a porous medium with a mixed ice-water zone. The modified SUTRA model correctly simulates the temperature and ice distributions in the peat bog. Two possible benchmark problems for groundwater and energy transport with ice formation and melting are proposed that may be used by other researchers for code comparison. ?? 2006 Elsevier Ltd. All rights reserved.

  20. Antioxidant properties, phenolic composition and potentiometric sensor array evaluation of commercial and new blueberry (Vaccinium corymbosum) and bog blueberry (Vaccinium uliginosum) genotypes.

    PubMed

    Kraujalyt?, Vilma; Venskutonis, Petras Rimantas; Pukalskas, Audrius; ?esonien?, Laima; Daubaras, Remigijus

    2015-12-01

    Antioxidant properties of juices of newly bred and known blueberry (Vaccinium corymbosum) genotypes and wild bog blueberry (Vaccinium uliginosum) were evaluated by ABTS(+) scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total phenolic content (TPC) and total anthocyanin content (TAC) assays. TPC varied in the range of 0.85-2.81mg gallic acid equiv./mL, RSC, FRAP and ORAC values were 6.38-20.9, 3.07-17.8 and 4.21-45.68?mol Trolox equiv./g, respectively. New blueberry genotypes and bog blueberry demonstrated stronger antioxidant properties and TAC than other studied genotypes. The content of quinic (203-3614?g/mL), chlorogenic (20.0-346.8?g/mL) acids and rutin (0.00-26.88?g/mL) measured by UPLC/ESI-QTOF-MS varied depending on the genotype. Juices were evaluated by electronic tongue; PCA score plot showed that the method discriminates different genotypes although some juice samples were located very closely and overlapping. Significant differences were observed between L(?), a(?), b(?) colour parameters of some genotypes. PMID:26041234

  1. Optical coatings deposited using ion assisted deposition

    Microsoft Academic Search

    James J. McNally; K. C. Jungling; F. L. Williams; J. R. McNeil

    1987-01-01

    The properties of TaâOâ and AlâOâ optical coatings deposited using oxygen-ion assisted deposition (IAD) were investigated. Previously, we reported preliminary results for TaâOâ and AlâOâ coatings deposited using IAD. In this paper, we present results illustrating the effects of oxygen-ion bombardment on film optical constants, environmental durability, and laser damage resistance. The coatings were bombarded with 200-, 300-, 500-, and

  2. DRY DEPOSITION MODULE FOR REGIONAL ACID DEPOSITION

    EPA Science Inventory

    Methods to compute surface dry deposition velocities for sulfur dioxide, sulfate, ozone, NO plus NO2, and nitric acid vapor over much of the North American continent have been developed for use with atmospheric numerical models of long-range transport and deposition. The resultin...

  3. Sampling Tsunami Deposits

    USGS Multimedia Gallery

    Dr. Starin Fernanda, Geological Survey & Mines Bureau of Sri Lanka, preparing a trench for sampling of tsunami deposit. Leaves on the surface days or weeks after the tsunami and blanket the sand deposited by the tsunami....

  4. Cascadia Tsunami Deposit Database

    USGS Publications Warehouse

    Peters, Robert; Jaffe, Bruce; Gelfenbaum, Guy; Peterson, Curt

    2003-01-01

    The Cascadia Tsunami Deposit Database contains data on the location and sedimentological properties of tsunami deposits found along the Cascadia margin. Data have been compiled from 52 studies, documenting 59 sites from northern California to Vancouver Island, British Columbia that contain known or potential tsunami deposits. Bibliographical references are provided for all sites included in the database. Cascadia tsunami deposits are usually seen as anomalous sand layers in coastal marsh or lake sediments. The studies cited in the database use numerous criteria based on sedimentary characteristics to distinguish tsunami deposits from sand layers deposited by other processes, such as river flooding and storm surges. Several studies cited in the database contain evidence for more than one tsunami at a site. Data categories include age, thickness, layering, grainsize, and other sedimentological characteristics of Cascadia tsunami deposits. The database documents the variability observed in tsunami deposits found along the Cascadia margin.

  5. Precision extruding deposition and

    E-print Network

    Sun, Wei

    Precision extruding deposition and characterization of cellular poly-e- caprolactone tissue a novel precision extruding deposition (PED) process technique to directly fabricate cellular poly scaffolds is always a challenged subject in regenerative medicine, particularly for load bearing scaffolds

  6. Climate change reduces the capacity of northern peatlands to absorb the atmospheric carbon dioxide: The different responses of bogs and fens

    NASA Astrophysics Data System (ADS)

    Wu, Jianghua; Roulet, Nigel T.

    2014-10-01

    The carbon (C) storage of northern peatlands is equivalent to ~34-46% of the ~795 T g C currently held in the atmosphere as CO2. Most studies report that northern peatlands are a sink of between 20 and 60 g CO2-C m-2 yr-1. Since peatland hydrology and biogeochemistry are very closely related to climate, there is concern whether northern peatlands will continue to function as C sinks with climate change. We used a coupled land surface scheme and peatland C model, called CLASS3W-MWM, to examine the sensitivity of peatland C to climate change. Based on the data available to constrain our model, we simulated the C dynamics of the Mer Bleue (MB) bog in eastern Canada and the Degerö Stormyr (DS) poor fen in northern Sweden for four Intergovernmental Panel on Climate Change (IPCC) climate change scenarios, i.e., A1B, A2, B1, and Commit, over four time periods, i.e., present day, 2030, 2060, and 2100. When the simulated future C fluxes were compared to the baseline fluxes under the present climate conditions, we found that fens were much more sensitive to climate change than bogs. Gross primary production (GPP) at MB significantly increased by 4-44% up to 2100 for all scenarios except Commit. GPP at DS significantly decreased by 34-39% for A1B and A2, and slightly increased by 6-10% for B1 and Commit. Total ecosystem respiration (TER) significantly increased by 7-57% for MB and 4-34% for DS up to 2100 for all scenarios except Commit. Net ecosystem production (NEP), therefore, significantly decreased. The bog, however, was still a C sink up to 2100, though much reduced, but the fen switched to a C source for A1B and A2 scenarios. Additional experiments where we climatically transplanted the study peatlands or forced vegetation changes when the fen became too dry showed similar but less dramatic results as the standard runs. Our results indicate that northern peatlands should be included in the C-coupled climate model to fully understand the response of C cycling in terrestrial ecosystems to climate change and to reduce the uncertainties for projecting the future climate.

  7. Pesticides in Surface Water, Bed Sediment, and Ground Water Adjacent to Commercial Cranberry Bogs, Lac du Flambeau Reservation, Vilas County, Wisconsin

    USGS Publications Warehouse

    Saad, David A.

    2005-01-01

    Pesticides commonly used on cranberries were detected in lakes, lake-bed sediment, and ground water of the Lac du Flambeau Reservation, Wisconsin adjacent to commercial cranberry bogs. Additionally, pesticides not typically used on cranberries were also detected. In water samples from Little Trout and the Corn Lakes, which are adjacent to commercial cranberry bogs, five targeted pesticides commonly used on cranberries (2,4-D, carbaryl, diazinon, napropamide, and norflurazon) were detected. No targeted pesticides were detected in Ike Walton Lake (the reference lake), which is not adjacent to commercial cranberry bogs. The non-targeted pesticide atrazine (not commonly used on cranberries) was detected in all lakes during all sample periods, with precipitation the likely source. Non-targeted pesticides metolachlor and oryzalin were also detected in samples from Ike Walton and the Corn Lake, but the sources are not apparent. Pesticide concentrations measured in lake samples were far below levels considered lethal to fish. In samples from the Trout River, which is used as a source of water to maintain lake levels in the Corn Lakes, the only pesticides detected were the non-targeted compounds atrazine and deethyl atrazine, indicating it was not a source of targeted compounds detected in the Corn Lakes. Only two pesticides (chlorpyrifos and metolachlor) were detected in bed-sediment samples collected from the lakes; chlorpyrifos from Little Trout Lake and metolachlor from the Corn Lakes. Four pesticides (the targeted compounds napropamide and norflurazon and the non-targeted compounds atrazine and deethyl atrazine) were detected in ground-water samples from two of four sampled monitor wells. The highest ground-water concentrations (up to 0.14 ?g/L napropamide and 0.56 ?g/L norflurazon) were measured in samples from the monitoring well located directly downgradient from the Corn Lakes and commercial cranberry operations. No pesticides were detected in samples from the reference well located upgradient from the Corn Lakes and cranberry operations. Further study is needed to identify additional pesticides as well as chronic effects on aquatic organisms to determine whether cranberry-related pesticides affect the lake ecosystems of the Lac du Flambeau Reservation.

  8. Application of soil magnetometry on peat-bogs and soils in areas affected by historical and prehistoric ore mining and smelting.

    NASA Astrophysics Data System (ADS)

    Magiera, Tadeusz; Mendakiewicz, Maria; Szuszkiewicz, Marcin; Chrost, Leszak

    2015-04-01

    The valleys of upper Brynica and Sto?a located in northern part of Upper Silesia were areas of historical human activities since prehistoric times. Historically confirmed mining and smelting of iron, silver and lead ores on this areas has been dated back to early Middle Ages, however recently some geochemical and radiometric analyses suggest even prehistoric time of such activities. The aim of this study was to check if it is possible to find any magnetic signal suggesting such activities in peat-bogs and soils of this area. This magnetic properties would be a result of presence of historical Technogenic Magnetic Particles (TMPs) arisen during the primitive smelting processes in the past. Many different types of TMPs were separated from the depth of 15-30 cm of soil profiles and also were present in deeper parts of peat-bogs accompanied by fine charcoal particles. The peat-bog horizons dated by radiocarbon (C14) for 2000 BC were contaminated by some heavy metals (Cu, Zn, Cd, Ag, Pb, Mn, Fe, Sr, Sc) and slightly increased magnetic susceptibility signal was also observed. On the base of soil surface magnetic measurement using MS2D Bartington sensor complemented by magnetic gradiometer system Grad 601-02 for the deeper soil penetration, some local magnetic anomalies were detected. In areas of local 'hot spots', the vertical cores up to 30 cm in depth were collected using the HUMAX core sampler. Vertical distribution of magnetic susceptibility along the cores was measured in the laboratory using the MS2C Bartington core sensor. The core section with increased susceptibility values were analyzed and TMPs were separated using a hand magnet. The separation of fine fraction of TMPs was carried out in an ultrasonic bath from the fine soil material suspended in isopropanol to avoid their coagulation. Irregular ceramic particles, ash and ore particles, as well as strong magnetic particles of metallic iron; all with diameter up to 10 mm and almost regular shape and rounded edges were magnetically separated from the 15-30 cm of topsoil cores. In order to determinate the mineralogical composition of magnetic particles in soil samples a SEM-EDS technique was used. On the base of the magnetic prescreening the archeological excavations on the study area are planning.

  9. Deposition Overview - Part II

    NSDL National Science Digital Library

    This YouTube video, created by Southwest Center for Microsystems Education (SCME), provides an overview of the deposition processes used to fabricate micro-sized devicesâ??. The lecture runs for 10:33 seconds and covers "a brief overview of chemical vapor deposition, physical vapor deposition, and electrodeposition." More information on desposition can be found on the SCME website. 

  10. Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed Through Syndromic Surveillance

    EPA Science Inventory

    In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air pollution is...

  11. Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardio-Pulmonary Emergency Department Visits

    EPA Science Inventory

    In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air pollution i...

  12. Peat bog wildfire smoke exposure in rural North Carolina is associated with Cardiopulmonary emergency department visits assessed through syndromic surveillance

    EPA Science Inventory

    Background: In June 2008 burning deposits of peat produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina (NC). While the association of mortality and morbidity with exposure to urban air ...

  13. Dry deposition velocities

    SciTech Connect

    Sehmel, G.A.

    1984-03-01

    Dry deposition velocities are very difficult to predict accurately. In this article, reported values of dry deposition velocities are summarized. This summary includes values from the literature on field measurements of gas and particle dry deposition velocities, and the uncertainties inherent in extrapolating field results to predict dry deposition velocities are discussed. A new method is described for predicting dry deposition velocity using a least-squares correlation of surface mass transfer resistances evaluated in wind tunnel experiments. 14 references, 4 figures, 1 table.

  14. Health assessment for Bog Creek Farm Site (BCFS) National Priorities List (NPL) site, Howell Township, Monmouth County, New Jersey, Region 2. CERCLIS No. NJD063157150. Final report

    SciTech Connect

    Not Available

    1989-04-10

    The Bog Creek Farm Site, located in a rural area of Howell Township, Monmouth County, New Jersey, is on the National Priorities List. In 1973 and 1974, various wastes were reportedly dumped at the site, including lacquer thinners, paint solvents and resins, disinfectants, animal carcasses, and residential debris. Sampling and analysis of on-site and off-site ground water, surface water, and sediments and of on-site waste and soil revealed several contaminants, primarily volatile organic compounds (VOCs), semi-volatile organic compounds, and heavy metals. Site contamination appears to be greatest immediately adjacent to an on-site waste-disposal trench. A potential public health threat exists from dermal absorption, ingestion, or inhalation of contamination from ground water, surface water, sediment, waste, and soil.

  15. Handbook on surficial uranium deposits. Chapter 3. World distribution relative to climate and physical setting

    SciTech Connect

    Carlisle, D

    1983-01-01

    This chapter discusses regional controls which affect the world distribution of surficial chemogenic uranium deposits. The most important of these are (1) climate, (2) geomorphology, including physiographic and climatic stability, and (3) provenance, i.e., the weathering terrain from which uranium and associated substances are derived. The three economically important environments are the calcrete environment, simple evaporative environments and paludal environments. Of these three categories, the calcrete uranium environment is probably the most uniquely constrained in terms of regional climate, geomorphic setting, provenance (vanadium as well as uranium) and especially the need for long term stability of both climate and physiography. Purely evaporative deposits, though subject to some of the same kinds of constraints, can also reflect local circumstances and a wider range of climates, physiographic settings, and source terrains. The third category encompassing bogs, marshes and organic-rich playas can form under an even wider range of climates and settings provided only that organic materials accumulate in abundance and are contacted by uranium-bearing waters. For all of these reasons and also because of the great economic importance of the calcrete environment as well as its relative novelty and complexity the discussion in this chapter is focused on calcrete, dolocrete and gypcrete uranium deposits. Objective data are reviewed first follwed by inferences and suggestions. 13 figures.

  16. Exploring for Copper Deposits

    NSDL National Science Digital Library

    2007-02-11

    In this activity, students assume the role of a geologist prospecting for copper deposits. From the background material, they will learn what ore deposits are and some important factors in their origin; and learn about a type of ore deposit known as a porphyry copper deposit. They will plot data from a table onto maps and use a geologic map, a soil geochemistry map, and a sediment geochemistry map to help locate the porphyry copper deposit. As a result of this activity, the students will be able to calculate an ore grade and determine whether or not an ore deposit is economically profitable based on its grade, size, and production costs. Worksheets and data tables are included.

  17. Uranium and organic matters: use of pyrolysis-gas chromatography, carbon, hydrogen, and uranium contents to characterize the organic matter from sandstone-type deposits

    USGS Publications Warehouse

    Leventhal, Joel S.

    1979-01-01

    Organic matter seems to play an important role in the genesis of uranium deposits in sandstones in the western United States. Organic materials associated with ore from the Texas coastal plain, Tertiary basins of Wyoming, Grants mineral belt of New Mexico, and the Uravan mineral belt of Utah and Colorado vary widely in physical appearance and chemical composition. Partial characterization of organic materials is achieved by chemical analyses to determine atomic hydrogen-to-carbon (H/C) ratios and by gas chromatographic analyses to determine the molecular fragments evolved during stepwise pyrolysis. From the pyrolysis experiments the organic materials can be classified and grouped: (a) lignites from Texas and Wyoming and (b) hydrogen poor materials, from Grants and Uravan mineral belts and Wyoming; (c) naphthalene-containing materials from Grants mineral belt and Wyoming; and (d) complex and aromatic materials from Uravan, Grants and Wyoming. The organic materials analyzed have atomic H/C ratios that range from approximately 0.3 to at least 1.5. The samples with higher H/C ratios yield pyrolysis products that contain as many as 30 carbon atoms per molecule. Samples with low H/C ratios are commonly more uraniferous and yield mostly methane and low-molecular-weight gases during pyrolysis.

  18. Lipid D/H Ratios from Multiple Sources and Deposits Indicate Drier Little Ice Age at Washington Island (4°43`N, 160°25`W), Central Pacific

    NASA Astrophysics Data System (ADS)

    Muegler, I.; Sachse, D.; Sachs, J. P.

    2010-12-01

    To compare the sensitivity of biomarker D/H ratios from two distinct climate archives, a lake and a peat bog on the Tropical Pacific Island of Terrania, compound-specific hydrogen isotope ratios (expressed as ?D values) were determined on lipid biomarkers from various biological sources deposited in the two climate archives. At present, Terrania or Washington Island (4°43`N, 160°25`W) permanently lies in the intertropical convergence zone (ITCZ) and receives an annual precipitation of 2,903 mm. The interior of this lens shaped island contains a freshwater lake and peat bogs. Previous studies on the lake sediments found evidence for a substantially drier climate at times during the Little Ice Age (AD 1400-1850) based on the lithologic transition from modern freshwater sediments to a sequence of pure cyanobacterial mat in concert with ?D values from total lipid extracts (Sachs et al., 2009). Here we report on ?D values from lipids of various sources: dinoflagellate algae (dinosterol and a saturated C30 sterol (4? -methyl-24-ethyl-5? -cholestan-3?-ol), microbial sources (diploptene and nC21 alkane) and higher plants (fern-7-ene, ?-sitosterol and stigmastanol). Mean ?D values from all lipids, measured in both archives, are significantly enriched in deuterium by between 22 and 86‰ during previously inferred drier climate conditions and simultaneously record the transition towards a freshwater lake at around AD1550. Measured ?D values of all lipids cover a wide range from -281‰ to -105‰ during freshwater deposition and from -185‰ to -50‰ when climate was drier. In agreement with the observed isotopic difference between lipids produced via the acetogenic and the mevalonic acid biosynthetic pathway ?D values for algae and higher plant sterols are depleted in deuterium relative to the nC21 alkane by 150‰ on average. The consistent ?D values from dinosterol and 4? -methyl-24-ethyl-5? -cholestan-3?-ol from the lake and peat deposits signify the robustness of these lipid ?D values to indicate hydrologic changes in the sedimentary record. ?D values among lipids of similar and disparate sources and/or biosynthetic origin from Washington Island lake (AD ~ 800-1550) and peat bog (AD~1200-1660) sediments are significantly enriched in deuterium prior to AD 1560/1640 and thus both suggest drier climate conditions resembling today’s environmental and depositional setting at Christmas Island which is located 300km SSE of Washington Island beyond the influence of the ITCZ.

  19. Shedding of ash deposits

    Microsoft Academic Search

    Ana Zbogar; Flemming Frandsen; Peter Arendt Jensen; Peter Glarborg

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of

  20. The Deposition Process

    NSDL National Science Digital Library

    This website includes an animation of the chemical vapor deposition process. Objective: Identify the process of chemical vapor deposition. This simulation is from Module 054 of the Process & Equipment I Cluster of the MATEC Module Library (MML). To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

  1. Natural bog pine ecosystem in southern Germany is a steady and robust sink of CO2 but a minor source of CH4

    NASA Astrophysics Data System (ADS)

    Hommeltenberg, Janina; Schmid, Hans Peter; Droesler, Matthias; Werle, Peter

    2013-04-01

    Natural peatland ecosystems sequester carbon dioxide. They do this slowly but steadily, but also emit methane in small rates. Thus peatlands have both positive and negative greenhouse gas balance impacts on the climate system due to their influence on atmospheric CO2 and CH4 concentration. We present data of net ecosystem CO2 exchange (NEE) of almost three years (July 2010 to March 2013) and of methane fluxes over a period of nine months (July 2012 to March 2013), measured by eddy covariance technique in the bog forest "Schechenfilz". The site (47°48' N; 11°19' E, 590 m a.s.l.) is an ICOS-ecosystems associate site, located in the pre-alpine region of southern Germany, where a natural Pinus mugo rotundata forest grows on an undisturbed, almost 6 m thick peat layer. The slow growing bog pines and their low rates of carbon sequestration, in combination with high water table and thus low availability of oxygen, lead to low carbon dioxide fluxes. Photosynthesis as well as soil respiration are considerably attenuated compared to upland sites. Additionally, the high soil water content is damping the impact of dry and hot periods on CO2 exchange. Thus the CO2 balance is very robust to changing environmental parameters. While the CO2 exchange is clearly related to soil temperature and photosynthetic active radiation, we have not yet identified a parameter that governs variations in methane exchange. Various environmental parameters appear to be related to methane emissions (including soil moisture, soil and air temperature and wind direction), but the scatter with respect to half hourly methane fluxes is too large to be useful for gap modeling. Analysis of daily averages reduces the scatter, but since methane exchange exhibits considerable daily variation, daily averages are not useful to fill data gaps of half hourly fluxes. In consequence, as the daily course is the summary result of all environmental parameters having influence on the methane exchange at the half-hour time scale of the measurements, the ensemble mean diurnal variation method over a suitable number of days is considered the most practical choice of gap filling method for methane fluxes at Schechenfilz site for estimating daily and annual sums. Overall, the annual CO2 uptake is estimated at a magnitude between -50 and -80 g C m-2 a-1, whereas the annual methane emissions are estimated to be about +6 g C m-2 a-1. Since N2O emissions can be neglected at natural peatland sites, the natural bog-pine ecosystem Schechenfilz is indicated to be a weak net sink of greenhouse gases in the past year, even if the higher global warming potential of methane is considered.

  2. Stratiform chromite deposit model

    USGS Publications Warehouse

    Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R., II

    2010-01-01

    Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusions host the majority of the world's chromium reserves and may contain significant platinum-group-element (PGE) mineralization. This model of stratiform chromite deposits is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. The model focuses on features that may be common to all stratiform chromite deposits as a way to gain insight into the processes that gave rise to their emplacement and to the significant economic resources contained in them.

  3. Ages of 24 widespread tephras erupted since 30,000 years ago in New Zealand, with re-evaluation of the timing and palaeoclimatic implications of the Lateglacial cool episode recorded at Kaipo bog

    NASA Astrophysics Data System (ADS)

    Lowe, David J.; Blaauw, Maarten; Hogg, Alan G.; Newnham, Rewi M.

    2013-08-01

    Tephras are important for the NZ-INTIMATE project because they link all three records comprising the composite inter-regional stratotype developed for the New Zealand climate event stratigraphy (NZ-CES). Here we firstly report new calendar ages for 24 widespread marker tephras erupted since 30,000 calendar (cal.) years ago in New Zealand to help facilitate their use as chronostratigraphic dating tools for the NZ-CES and for other palaeoenvironmental and geological applications. The selected tephras comprise 12 rhyolitic tephras from Taupo, nine rhyolitic tephras from Okataina, one peralkaline rhyolitic tephra from Tuhua, and one andesitic tephra each from Tongariro and Egmont/Taranaki volcanic centres. Age models for the tephras were obtained using three methods: (i) 14C-based wiggle-match dating of wood from trees killed by volcanic eruptions (these dates published previously); (ii) flexible depositional modelling of a high-resolution 14C-dated age-depth sequence at Kaipo bog using two Bayesian-based modelling programs, Bacon and OxCal's P_Sequence function, and the IntCal09 data set (with SH offset correction -44 ± 17 yr); and (iii) calibration of 14C ages using OxCal's Tau_Boundary function and the SHCal04 and IntCal09 data sets. Our preferred dates or calibrated ages for the 24 tephras are as follows (youngest to oldest, all mid-point or mean ages of 95% probability ranges): Kaharoa AD 1314 ± 12; Taupo (Unit Y) AD 232 ± 10; Mapara (Unit X) 2059 ± 118 cal. yr BP; Whakaipo (Unit V) 2800 ± 60 cal. yr BP; Waimihia (Unit S) 3401 ± 108 cal. yr BP; Stent (Unit Q) 4322 ± 112 cal. yr BP; Unit K 5111 ± 210 cal. yr BP; Whakatane 5526 ± 145 cal. yr BP; Tuhua 6577 ± 547 cal. yr BP; Mamaku 7940 ± 257 cal. yr BP; Rotoma 9423 ± 120 cal. yr BP; Opepe (Unit E) 9991 ± 160 cal. yr BP; Poronui (Unit C) 11,170 ± 115 cal. yr BP; Karapiti (Unit B) 11,460 ± 172 cal. yr BP; Okupata 11,767 ± 192 cal. yr BP; Konini (bed b) 11,880 ± 183 cal. yr BP; Waiohau 14,009 ± 155 cal. yr BP; Rotorua 15,635 ± 412 cal. yr BP; Rerewhakaaitu 17,496 ± 462 cal. yr BP; Okareka 21,858 ± 290 cal. yr BP; Te Rere 25,171 ± 964 cal. yr BP; Kawakawa/Oruanui 25,358 ± 162 cal. yr BP; Poihipi 28,446 ± 670 cal. yr BP; and Okaia 28,621 ± 1428 cal. yr BP. Secondly, we have re-dated the start and end of the Lateglacial cool episode (climate event NZce-3 in the NZ-CES), previously referred to as the Lateglacial climate reversal, as defined at Kaipo bog in eastern North Island, New Zealand, using both Bacon and OxCal P_Sequence modelling with the IntCal09 data set. The ca 1200-yr-long cool episode, indicated by a lithostratigraphic change in the Kaipo peat sequence to grey mud with lowered carbon content, and a high-resolution pollen-derived cooling signal, began 13,739 ± 125 cal. yr BP and ended 12,550 ± 140 cal. yr BP (mid-point ages of the 95% highest posterior density regions, Bacon modelling). The OxCal modelling, generating almost identical ages, confirmed these ages. The Lateglacial cool episode (ca 13.8-12.6 cal. ka BP) thus overlaps a large part of the entire Antarctic Cold Reversal chronozone (ca 14.1-12.4 cal. ka BP or ca 14.6-12.8 cal. ka BP), and an early part of the Greenland Stadial-1 (Younger Dryas) chronozone (ca 12.9-11.7 cal. ka BP). The timing of the Lateglacial cool episode at Kaipo is broadly consistent with the latitudinal patterns in the Antarctic Cold Reversal signal suggested for the New Zealand archipelago from marine and terrestrial records, and with records from southern South America.

  4. A late Holocene record of trace metal deposition in lake sediments near Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Beal, S. A.; Kelly, M. A.; Jackson, B. P.; Osterberg, E. C.; Stroup, J. S.; Baker, R. A.

    2010-12-01

    Records of atmospheric metal deposition have been used extensively in the Northern Hemisphere to examine historical events ranging from the evolution of ancient metallurgy to climatic change. Establishing such a record in tropical South America is pertinent due to ongoing questions about the metallurgical history of pre-colonial Andean civilizations, recent atmospheric pollution levels, and late Holocene climate variability. Here we present a late Holocene record of the Ag, As, Cd, Co, Cu, Hg, Ni, Pb, Sr, Zn, and Pb isotopic compositions of atmospheric deposition from three 1.5 m-long lake cores and one 5 m-long bog core recovered near Quelccaya Ice Cap (13.9 °S), in the southeastern Peruvian Andes. The bog core, representing deposition from the present to at least 2415 yr BP, records relatively stable concentrations of As, Co, Cu, Hg, Ni, Pb, Sr, and Zn between 2415 (±78) and 916 (±29) yr BP. However, Ag and Cd exhibit brief gradual enrichments over background levels by factors of 6 and 11, respectively, shortly after 2415 (±78) yr BP as a possible result of ancient metallurgy. Sometime following the 916 (±29) yr BP date, Ag, As, Cd, Cu, Hg, Ni, Pb, and Sr abruptly become enriched by factors of 10, 37, 11, 11, 47, 6, 16, and 24, respectively, possibly from anthropogenic sources and/or the 1600 AD eruption of Huaynaputina in southern Peru. These enrichments are concurrent with a shift in 206Pb/207Pb to 1.182 from background levels of 1.213 (±0.002, n=20). A subsequent quiescent period in metal concentrations is marked by a brief return to background 206Pb/207Pb values, followed by erratic 206Pb/207Pb values yet decreased metal concentrations in the most recent sediments. Only Hg is enriched over background levels, by a factor of 3, in the most recent sediment. Forthcoming higher-resolution data from the three lake cores will utilize pre-industrial lead isotope ratios and Ti, Zr, and REE fluxes to examine past variability of the El Niño-Southern Oscillation, the position of the Intertropical Convergence Zone, and the extent of nearby mountain glaciers, including Quelccaya Ice Cap.

  5. System for depositing thin films

    NASA Technical Reports Server (NTRS)

    Tashbar, P. W. (inventor)

    1974-01-01

    A system for depositing a thin film of one material on another is described. A mass filter is interposed between the source of material being deposited and the object upon which deposition is being made.

  6. Ash deposit workshop: Class outline

    SciTech Connect

    Hatt, R. [Commercial Testing & Engineering Co., Lexington, KY (United States)

    1996-12-31

    Ash deposits formed from the combustion of coal and other fuels have plagued the steam production industry from the start. The ash fusion test has been around for over eighty years. As steam plant size increased, so have the problems associated with ash deposits. This workshop is designed to cover: (1) The basic types of deposits. (2) Causes of deposits. (3) Analytical procedures for resolving, or at least providing information about deposits and fuels, and (4) Deposit removal and reduction techniques.

  7. Enhanced deposition rates in plasma sputter deposition

    NASA Astrophysics Data System (ADS)

    Thomann, A. L.; Charles, C.; Brault, P.; Laure, C.; Boswell, R.

    1998-08-01

    Langmuir probe and emission spectroscopic measurements are performed in a high frequency (100 MHz) argon plasma used for the sputter deposition process of thin films of palladium (dedicated to catalysis applications). The metal source is a helicoidal palladium wire which is negatively biased with respect to the plasma potential. This induces sputtering by the ions present in the plasma. The probe results show that the presence of the helicoidal wire in the chamber does not affect the total ion flux at the substrate location. However, as the bias voltage on the wire and/or the argon pressure are increased, a secondary direct current (DC) discharge is created inside the helicoidal wire which follows a Paschen-like law; the breakdown voltage is lower than in the case of a conventional Ar discharge, probably as a result of the presence of primary electrons generated by the main high frequency (HF) plasma. This second discharge is characterized by a strong 0963-0252/7/3/002/img8 flux peak inside the helicoidal wire, which probably arises from a hollow cathode type discharge. From emission spectroscopy and deposition analysis, it is shown that this secondary plasma causes an increase of the sputtered Pd atom number and, consequently, an enhanced deposition rate.

  8. Evaluations of the TiO2/simulated solar UV degradations of XAD fractions of natural organic matter from a bog lake using size-exclusion chromatography.

    PubMed

    Valencia, Sergio; Marín, Juan M; Restrepo, Gloria; Frimmel, Fritz H

    2013-09-15

    This work reports on the changes in compositions of humic acids (HAs) and fulvic acids (FAs) during photocatalytic degradation. The HAs and FAs were obtained from the XAD-resin fractionation of natural-organic matter (NOM) from a bog lake (Lake Hohloh, Black Forest, Germany). Degussa P-25 titanium dioxide (TiO2) in a suspension and a solar UV simulator (batch reactor) were used in the experiments. The photocatalytic degradation of the HAs and FAs were monitored using size-exclusion chromatography (SEC) equipped with dissolved organic carbon (DOC) and ultraviolet (UV254) detection (SEC-DOC and SEC-UV254) and UV-Vis spectrophotometry. The evolutions of the photocatalytic degradations of the HA and FA fractions were selective. The photocatalytic degradation started with the degradations of high molecular weight compounds with relatively high UV254 absorbances in the HA and FA fractions to yield low molecular weight compounds showing less specific UV254 absorbances. Observance of the same tendency for the original NOM from Lake Hohloh indicates that these XAD-fractions still having complex compound mixtures. However, the larger molecular weight fractions of the FAs showed higher preferential adsorptions onto TiO2, which caused their faster degradation rates. Furthermore, FAs showed a greater reduction of the total THM formation potential (TTHMFP) and the organic halogen compounds adsorbable on activated carbon formation potential (AOXFP), in comparison with the HAs. PMID:23863374

  9. 75 FR 20041 - Deposits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-16

    ...DEPARTMENT OF THE TREASURY Office of Thrift Supervision Deposits AGENCY: Office of Thrift Supervision (OTS), Treasury. ACTION: Notice and...U.S.C. 3507. The Office of Thrift Supervision within the Department of the Treasury...

  10. World oil shale deposits

    SciTech Connect

    Hook, C.O.; Russell, P.L.

    1982-01-01

    The article estimates resources in-place and their oil equivalent. The major deposits are described in the U.S., Australia, USSR, Peoples Republic of China, Morocco, Israel, Jordan, Syria, Europe and South America. 2 refs.

  11. Automatic Payroll Deposit System.

    ERIC Educational Resources Information Center

    Davidson, D. B.

    1979-01-01

    The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)

  12. AIR QUALITY AND DEPOSITION

    EPA Science Inventory

    The pollution climate of an area is influenced by meteorology and emissions of air pollutants at local and regional scales. he physical and chemical state of the atmosphere determines pollutant transport, dilution, chemical transformation, and ultimately deposition. n many cases ...

  13. EDITORIAL: Atomic layer deposition Atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Godlewski, Marek

    2012-07-01

    The growth method of atomic layer deposition (ALD) was introduced in Finland by Suntola under the name of atomic layer epitaxy (ALE). The method was originally used for deposition of thin films of sulphides (ZnS, CaS, SrS) activated with manganese or rare-earth ions. Such films were grown for applications in thin-film electroluminescence (TFEL) displays. The ALE mode of growth was also tested in the case of molecular beam epitaxy. Films grown by ALD are commonly polycrystalline or even amorphous. Thus, the name ALE has been replaced by ALD. In the 80s ALD was developed mostly in Finland and neighboring Baltic countries. Deposition of a range of different materials was demonstrated at that time, including II-VI semiconductors (e.g. CdTe, CdS) and III-V (e.g. GaAs, GaN), with possible applications in e.g. photovoltaics. The number of publications on ALD was slowly increasing, approaching about 100 each year. A real boom in interest came with the development of deposition methods of thin films of high-k dielectrics. This research was motivated by a high leakage current in field-effect transistors with SiO2-based gate dielectrics. In 2007 Intel introduced a new generation of integrated circuits (ICs) with thin films of HfO2 used as gate isolating layers. In these and subsequent ICs, films of HfO2 are deposited by the ALD method. This is due to their unique properties. The introduction of ALD to the electronics industry led to a booming interest in the ALD growth method, with the number of publications increasing rapidly to well above 1000 each year. A number of new applications were proposed, as reflected in this special issue of Semiconductor Science and Technology. The included articles cover a wide range of possible applications—in microelectronics, transparent electronics, optoelectronics, photovoltaics and spintronics. Research papers and reviews on the basics of ALD growth are also included, reflecting a growing interest in precursor chemistry and growth processes. Summarizing, this special issue of Semiconductor Science and Technology reflects the rapidly growing interest in the ALD growth method and demonstrates the wide range of possible practical applications of ALD-grown materials, not only of high-k dielectrics, but also of a range of different materials (e.g. ZnO). Finally, I would like to thank the IOP editorial staff, in particular Alice Malhador, for their support and efforts in making this special issue possible.

  14. Resedimented salt deposits

    SciTech Connect

    Slaczka, A.; Kolasa, K. (Jagiellonian Univ., Krakow (Poland))

    1988-08-01

    Carparthian foredeep's Wieliczka salt mine, unique gravity deposits were lately distinguished. They are mainly built of salt particles and blocks with a small admixture of fragments of Miocene marls and Carpathian rocks, deposited on precipitated salt. The pattern of sediment distribution is similar to a submarine fan. Gravels are dominant in the upper part and sands in lower levels, creating a series of lobes. Coarse-grained deposits are represented by disorganized, self-supported conglomerates passing into matrix-supported ones, locally with gradation, and pebbly sandstones consisting of salt grains and scattered boulder-size clasts. The latter may show in the upper part of a single bed as indistinct cross-bedding and parallel lamination. These sediments are interpreted as debris-flow and high-density turbidity current deposits. Salt sandstones (saltstones) which build a lower part of the fan often show Bouma sequences and are interpreted as turbidity-current deposits. The fan deposits are covered by a thick series of debrites (olistostromes) which consist of clay matrix with salt grains and boulders. The latter as represented by huge (up to 100,000 m{sup 3}) salt blocks, fragments of Miocene marls and Carpathian rocks. These salt debrites represent slumps and debris-flow deposits. The material for resedimented deposits was derived from the southern part of the salt basin and from the adjacent, advancing Carpathian orogen. The authors believe the distinct coarsening-upward sequence of the series is the result of progressive intensification of tectonic movements with paroxysm during the sedimentation of salt debrites (about 15 Ma).

  15. Pulsed laser deposition: Prospects for commercial deposition of epitaxial films

    SciTech Connect

    Muenchausen, R.E.

    1999-03-01

    Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique for the deposition of thin films. The vapor source is induced by the flash evaporation that occurs when a laser pulse of sufficient intensity (about 100 MW/cm{sup 2}) is absorbed by a target. In this paper the author briefly defines pulsed laser deposition, current applications, research directed at gaining a better understanding of the pulsed laser deposition process, and suggests some future directions to enable commercial applications.

  16. Becquerel Crater Deposit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 28 May 2002) The finely layered deposit in Becquerel crater, seen in the center of this THEMIS image, is slowly being eroded away by the action of windblown sand. Dark sand from a source north of the bright deposit is collecting along its northern edge, forming impressive barchan style dunes. These vaguely boomerang-shaped dunes form with their two points extending in the downwind direction, demonstrating that the winds capable of moving sand grains come from the north. Grains that leave the dunes climb the eroding stair-stepped layers, collecting along the cliff faces before reaching the crest of the deposit. Once there, the sand grains are unimpeded and continue down the south side of the deposit without any significant accumulation until they fall off the steep cliffs of the southern margin. The boat-hull shaped mounds and ridges of bright material called yardangs form in response to the scouring action of the migrating sand. To the west, the deposit has thinned enough that the barchan dunes extend well into the deeply eroded north-south trending canyons. Sand that reaches the south side collects and reforms barchan dunes with the same orientation as those on the north side of the deposit. Note the abrupt transition between the bright material and the dark crater floor on the southern margin. Steep cliffs are present with no indication of rubble from the obvious erosion that produced them. The lack of debris at the base of the cliffs is evidence that the bright material is readily broken up into particles that can be transported away by the wind. The geological processes that are destroying the Becquerel crater deposit appear active today. But it is also possible that they are dormant, awaiting a particular set of climatic conditions that produces the right winds and perhaps even temperatures to allow the erosion to continue.

  17. Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed through Syndromic Surveillance

    PubMed Central

    Stone, Susan L.; Cascio, Wayne E.; Neas, Lucas M.; Kilaru, Vasu J.; Carraway, Martha Sue; Szykman, James J.; Ising, Amy; Cleve, William E.; Meredith, John T.; Vaughan-Batten, Heather; Deyneka, Lana; Devlin, Robert B.

    2011-01-01

    Background: In June 2008, burning peat deposits produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina. Although the association of mortality and morbidity with exposure to urban air pollution is well established, the health effects associated with exposure to wildfire emissions are less well understood. Objective: We investigated the effects of exposure on cardiorespiratory outcomes in the population affected by the fire. Methods: We performed a population-based study using emergency department (ED) visits reported through the syndromic surveillance program NC DETECT (North Carolina Disease Event Tracking and Epidemiologic Collection Tool). We used aerosol optical depth measured by a satellite to determine a high-exposure window and distinguish counties most impacted by the dense smoke plume from surrounding referent counties. Poisson log-linear regression with a 5-day distributed lag was used to estimate changes in the cumulative relative risk (RR). Results: In the exposed counties, significant increases in cumulative RR for asthma [1.65 (95% confidence interval, 1.25–2.1)], chronic obstructive pulmonary disease [1.73 (1.06–2.83)], and pneumonia and acute bronchitis [1.59 (1.07–2.34)] were observed. ED visits associated with cardiopulmonary symptoms [1.23 (1.06–1.43)] and heart failure [1.37 (1.01–1.85)] were also significantly increased. Conclusions: Satellite data and syndromic surveillance were combined to assess the health impacts of wildfire smoke in rural counties with sparse air-quality monitoring. This is the first study to demonstrate both respiratory and cardiac effects after brief exposure to peat wildfire smoke. PMID:21705297

  18. films deposited by chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Asafa, T. B.; Witvrouw, A.; Morcos, B. S.; Vanstreels, K.; Said, S. A. M.

    2014-08-01

    A few properties of polycrystalline silicon germanium (poly-Si1- x Ge x ) films can be tailored by modulating the germanium incorporation. In this paper, the structural, mechanical and electrical properties of heavily doped ultrathin (~100 nm) poly-Si1- x Ge x films (0.84 ? x ? 0.88) fabricated by low-pressure chemical vapour deposition were investigated. For a boron concentration of ~2.2 × 1021 atoms/cm3, a slight increase of germanium fraction significantly enhances the deposition rate, crystallinity and Hall mobility while having negligible influence on the Young's modulus and hardness. The grain size increases from ~6 to ~12 nm while the grain structure becomes more columnar. In addition, the resistivity decreases from 7.4 to 1.1 m ? cm with a corresponding increase in the Hall mobility from ~0.9 to ~4.2 cm2 V-1 s-1. However, the Young's modulus (~101 GPa) and hardness (~8.8 GPa) are virtually unaffected within the range of germanium fraction explored. In practice, poly-SiGe layer having low resistivity, high modulus, high mobility and low surface roughness can be successfully applied for resonators, biosensors and nanoswitches among others.

  19. Vacuum arc deposition devices

    SciTech Connect

    Boxman, R.L.; Zhitomirsky, V.N. [Electrical Discharge and Plasma Laboratory, Faculty of Engineering, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978 (Israel)

    2006-02-15

    The vacuum arc is a high-current, low-voltage electrical discharge which produces a plasma consisting of vaporized and ionized electrode material. In the most common cathodic arc deposition systems, the arc concentrates at minute cathode spots on the cathode surface and the plasma is emitted as a hypersonic jet, with some degree of contamination by molten droplets [known as macroparticles (MPs)] of the cathode material. In vacuum arc deposition systems, the location and motion of the cathode spots are confined to desired surfaces by an applied magnetic field and shields around undesired surfaces. Substrates are mounted on a holder so that they intercept some portion of the plasma jet. The substrate often provides for negative bias to control the energy of depositing ions and heating or cooling to control the substrate temperature. In some systems, a magnetic field is used to guide the plasma around an obstacle which blocks the MPs. These elements are integrated with a deposition chamber, cooling, vacuum gauges and pumps, and power supplies to produce a vacuum arc deposition system.

  20. Impact of Long-term N Deposition on N Mobility and Transformations in A Northern Peatland

    NASA Astrophysics Data System (ADS)

    Xing, Y.; Blodau, C.

    2008-12-01

    Nitrogen (N) saturation in peatland ecosystem be expected at the total inorganic N deposition rates of 1.5 - 2.0 g m-2 yr-1, but whether the threshold value can be modified by the availability of phosphorus (P) and potassium (K) and changes in vegetation community structure is unknown. To address this question, a field experiment and 15N tracer study were conducted on 18 research plots in the Sphagnum- dominated, ombrotrophic bog Mer Bleue, Canada. Significant increases in N concentration and a reduced C: N ratio (32.1) were observed in the exclusively N fertilized plots (1.6 g N m-2 yr-1 loading) rather than plots with even higher N loading but additional P and K fertilization. Except in the highest N loading plots (6.4 g N m-2 yr-1) with P and K input, there were no significant differences in NH4+ and NO3- concentration in soil solution among most of plots. NH4+ and NO3- concentrations ranged from 2.2 to 4.2 ?mol L-1 and 4.6 to 7.7 ?mol L-1, respectively, while in the highest N loading plots, average NH4+ and NO3- concentration were 9.2 and 15.5 ?mol L-1, respectively, indicating some potential for nitrate leaching. Application of P and K significantly increased the available P and K by a factor of 100 compared to controls and exclusive N fertilized plots. P was depleted in exclusively N fertilized plots (1.9 ?mol L-1 PO43-); whereas K still remained high, indicating that N deposition resulted in P limitation of the vegetation. This result is consistent with previous studies, but the inorganic N concentrations were still low and no N saturation occurred. An efficient transformation into organic nitrogen can be possible explanation. Enhanced P and K availability slowed the translocation of mineral N, but when N loading was higher than 3.2 g N m-2 yr- 1, even the application of P and K can not prevent some nitrate leaching. The isotope study showed that mosses had a higher mass based N retention capacity than vascular plant, but with the nutrient loading, the N retention power of vascular plant increased. Considering the decline in moss biomass and shift to vascular plant in high nutrient loading plots, the N filter function of ombrotrophic bogs will be highly influenced by interactions with shifts in plant community structure and other nutrients.

  1. The effects of ecological restoration, on soil-pore water quality and DOC concentrations, on a British upland blanket bog.

    NASA Astrophysics Data System (ADS)

    Qassim, Suzane; Dixon, Simon; Rowson, James; Worrall, Fred; Evans, Martin

    2013-04-01

    Polluted by past atmospheric deposition, eroded and burnt, the Bleaklow plateau (Peak district National Park, UK) has long been degraded. Peatlands are important carbon reservoirs and can act as sources or sinks of carbon. Dissolved organic carbon (DOC) is carbon lost from peatlands via the fluvial pathway and as the major component of water colour it is costly to remove during water treatment processes. The Bleaklow Summit peatlands, were subjected to a large wildfire in 2003 devegetating 5.5km2. This fire prompted stakeholders to initiate a large-scale programme of restoration of the plateau. This study considered restoration techniques across four sites: all four sites were seeded with lawn grass, limed and fertilised; to raise the pH and allow establishment of vegetation. In addition to these interventions, one site also had a mulch of Calluna vulgaris applied to the surface to allow soil stabilisation and promote vegetation establishment and another site had biodegradable geojute textile mesh installed, to stabilize the steep gully surfaces. Another site had a gully block installed, to reduce peat desiccation and erosion. This study will compare the four restored sites to two types of comparators: bare soil sites where no restoration was undertaken and a naturally vegetated site unaffected by the 2003 wildfire. Each site had six replicate dipwells, installed in two groups of three. The depth to the water table was monitored and soil water samples collected for analysis, monthly for 5 years, from Nov 2006 - Jan 2012. No significant difference in DOC concentration was found between control and treated sites. There was, however, a significant difference in DOC composition between sites and over the 5 year period of monitoring. UV-vis absorbance of the samples is used to quantify the fulvic to humic components of DOC. The vegetated control was not significantly different to the bare sites; however the vegetated control had a significantly greater humic fraction of than the seeded, limed and fertilised only site, as well as the seeded, limed, C. vulgaris mulched site. This is possibly related to vegetation and litter layer establishment. A suite of water quality data (conductivity, pH and cation data) are now being analysed in combination with DOC to increase understanding of the relationship between bare site re-vegetation and DOC compositional change.

  2. A 15 000-year record of climate change in northern New Mexico, USA, inferred from isotopic and elemental contents of bog sediments

    USGS Publications Warehouse

    Cisneros-Dozal, L. M.; Heikoop, J.M.; Fessenden, J.; Anderson, R. Scott; Meyers, P.A.; Allen, C.D.; Hess, M.; Larson, T.; Perkins, G.; Rearick, M.

    2010-01-01

    Elemental (C, N, Pb) and isotopic (??13C, ??15N) measurements of cored sediment from a small bog in northern New Mexico reveal changes in climate during the Late Pleistocene and Holocene. Abrupt increases in Pb concentration and ??13C values ca. 14 420 cal. YBP indicate significant runoff to the shallow lake that existed at that time. Weathering and transport of local volcanic rocks resulted in the delivery of Pb-bearing minerals to the basin, while a 13C-enriched terrestrial vegetation source increased the ??13C values of the sedimentary material. Wet conditions developed over a 300 a period and lasted for a few hundred years. The Younger Dryas period (ca. 12 700-11 500 cal. YBP) caused a reduction in terrestrial productivity reflected in decreasing C/N values, ??15N values consistently greater than 0??? and low organic content. By contrast, aquatic productivity increased during the second half of this period, evidenced by increasing ??13C values at the time of highest abundance of algae. Dry conditions ca. 8 000-6 000 cal. YBP were characterised by low organic carbon content and high Pb concentrations, the latter suggesting enhanced erosion and aeolian transport of volcanic rock. The range in ??13C, ??15N and C/N values in the sedimentary record fall within the range of modern plants, except during the periods of runoff and drought. The sedimentary record provides evidence of natural climate variability in northern New Mexico, including short- (multi-centennial) and long-(millennial) term episodes during the Late Pleistocene and Holocene. Copyright ?? 2010 John Wiley & Sons, Ltd.

  3. Holocene monsoon climate documented by oxygen and carbon isotopes from lake sediments and peat bogs in China: a review and synthesis

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawu; Chen, Fahu; Holmes, Jonathan A.; Li, Hui; Guo, Xiaoyan; Wang, Junlan; Li, Shuang; Lü, Yanbin; Zhao, Yan; Qiang, Mingrui

    2011-07-01

    There has been much recent debate about Holocene climate variation in the monsoon region of China, especially the temporal pattern of variations in precipitation, the time-transgressive nature of the Holocene precipitation maximum, and the extent to which variations in regions influenced by the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM) have been synchronous. We summarize and compare carbonate oxygen-isotope records (? 18O carb) from ten lakes within the present-day ISM region. We discuss their paleoclimate significance considering the present-day moisture source, isotopic composition of precipitation and the hydrological setting. The ? 18O carb records are controlled mainly by the isotopic composition of lake water, which in turn is a function of regional Precipitation/Evaporation (P/E) balance and the proportion of precipitation that is monsoon-derived. We normalized the ? 18O carb data and used these records to generate an integrated moisture index. This index, along with oxygen-isotope records from speleothems and carbon-isotope records (? 13C org) from peats within the monsoon region, suggests that Holocene climate was broadly synchronous across the monsoon region and, within the limits of accuracy of the existing age models, provides no strong evidence for previously-proposed anti-phasing of the ISM and the EASM. Stable-isotope records from lake sediments and peat bogs have excellent potential for providing high-quality paleoclimate data for monsoon Asia, and complement high-resolution speleothem sequences, which are only found in certain localities.

  4. Chemical vapor deposition growth

    Microsoft Academic Search

    R. P. Ruth; H. M. Manasevit; A. G. Campbell; R. E. Johnson; J. L. Kenty; L. A. Moudy; G. L. Shaw; W. I. Simpson; J. J. Yang

    1978-01-01

    The objective was to investigate and develop chemical vapor deposition (CVD) techniques for the growth of large areas of Si sheet on inexpensive substrate materials, with resulting sheet properties suitable for fabricating solar cells that would meet the technical goals of the Low Cost Silicon Solar Array Project. The program involved six main technical tasks: (1) modification and test of

  5. MODELED WET NITRATE DEPOSITION

    EPA Science Inventory

    Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface water bodies. See below regarding decriptions on how original data was produced. These data will be part of futur...

  6. Trouvelot Crater Deposit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    Like many of the craters in the Oxia Palus region of Mars, Trouvelot Crater hosts an eroded, light-toned, sedimentary deposit on its floor. Compared with the much larger example in Becquerel Crater to the NE, the Trouvelot deposit has been so eroded by the scouring action of dark, wind-blown sand that very little of it remains. Tiny outliers of bright material separated from the main mass attest to the once, more really extensive coverage by the deposit. A similar observation can be made for White Rock, the best known example of a bright, crater interior deposit. The origin of the sediments in these deposits remains enigmatic but they are likely the result of fallout from ash or dust carried by the thin martian atmosphere.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. Metal oxides deposited using ion assisted deposition at low temperature

    Microsoft Academic Search

    Forrest L. Williams; D. W. Reicher; C. Juang; J. R. McNeil

    1989-01-01

    We have investigated the use of ion assisted deposition (IAD) to deposit thin films of AlâOâ, TaâOâ, and TiOâ at a low substrate temperature (T\\/sub sub\\/approx. =100 °C). Refractive indices of films deposited using IAD initially increase for a corresponding increase in ion current density until the current density reaches a so-called ''critical value.'' Films deposited at bombardment levels greater

  8. Atmospheric N deposition and feedbacks on net ecosystem CO2 exchange at a semi-natural peatland site

    NASA Astrophysics Data System (ADS)

    Hurkuck, Miriam; Brümmer, Christian; Spott, Oliver; Flessa, Heinz; Kutsch, Werner L.

    2013-04-01

    Large areas of Northern Germany have been converted from natural peat bogs to arable land and were subjected to draining and peat cutting in the past. The few protected peatland areas remaining are affected by high nitrogen (N) deposition. This is the case at our study site - a semi-natural raised bog - which although located in a natural park, is surrounded by highly fertilized agricultural land and highly emitting animal husbandry farms. In this study, we use a combined approach of two independent methods to quantify atmospheric N deposition. We further investigate possible feedbacks of seasonal variation in N deposition on net ecosystem CO2 exchange (NEE). Fluxes of ammonia (NH3) and its atmospheric reactants are measured by a KAPS-denuder system. Additionally, total N input from the atmosphere into a soil-plant model ecosystem is investigated by a 15N dilution method called 'Integrated Total Nitrogen Input' (ITNI). With this approach, we allocate atmospheric N after its uptake by the ecosystem into its different fractions and investigate both plant-species effects (Lolium multiflorum, Eriophorum vaginatum) and influences of the plant biomass production induced by different amounts of fertilizer addition. Continuous eddy-covariance measurements are carried out to measure NEE. Maximum NH3 depositions of 0.41 ± 0.04 kg ha-1 week-1 were found in spring 2012. The proportion of fluxes of other N compounds such as HNO3, aerosol NH4 and NO3 was usually around 20 % of total dry N measured by KAPS denuders. In total, dry N deposition was 11.2 ± 0.9 kg N ha-1 yr-1 over the first year of experiments. Complemented with wet N measurements using bulk samplers, total N depositions of about 25.0 kg ha-1 yr-1 were found. The mean atmospheric N uptake determined with the ITNI system was 3.99 ± 0.82 mg N g-1 dry weight from July to October 2011. About two third of total deposited airborne N was allocated in above-ground plant biomass and roots. Upscaling of data based on pot area resulted in a total N input of 24.06 ± 3.55 kg N ha-1 yr-1 into the ITNI system. Cumulative NEE was about -241 g C m-2 yr-1 for the first year of experiments with the strongest CO2 uptake being observed during spring and early summer. During winter, photosynthesis slightly exceeded respiration. Our results show that the critical load of N deposition for peatlands (~5 kg N ha-1 yr-1) is fivefold exceeded. Most likely, the intensive agricultural land management of the surrounding areas leads to this high N deposition into the protected peatland area. Future changes in plant species composition and the local hydrological regime cannot be excluded. A link between N input and comparatively high CO2 uptake will be discussed.

  9. Uranium deposits of Brazil

    SciTech Connect

    NONE

    1991-09-01

    Brazil is a country of vast natural resources, including numerous uranium deposits. In support of the country`s nuclear power program, Brazil has developed the most active uranium industry in South America. Brazil has one operating reactor (Angra 1, a 626-MWe PWR), and two under construction. The country`s economic challenges have slowed the progress of its nuclear program. At present, the Pocos de Caldas district is the only active uranium production. In 1990, the Cercado open-pit mine produced approximately 45 metric tons (MT) U{sub 3}O{sub 8} (100 thousand pounds). Brazil`s state-owned uranium production and processing company, Uranio do Brasil, announced it has decided to begin shifting its production from the high-cost and nearly depleted deposits at Pocos de Caldas, to lower-cost reserves at Lagoa Real. Production at Lagoa Real is schedules to begin by 1993. In addition to these two districts, Brazil has many other known uranium deposits, and as a whole, it is estimated that Brazil has over 275,000 MT U{sub 3}O{sub 8} (600 million pounds U{sub 3}O{sub 8}) in reserves.

  10. Granulicella paludicola gen. nov., sp. nov., Granulicella pectinivorans sp. nov., Granulicella aggregans sp. nov. and Granulicella rosea sp. nov., acidophilic, polymer-degrading acidobacteria from Sphagnum peat bogs.

    PubMed

    Pankratov, Timofey A; Dedysh, Svetlana N

    2010-12-01

    Five strains of strictly aerobic, heterotrophic bacteria that form pink-red colonies and are capable of hydrolysing pectin, xylan, laminarin, lichenan and starch were isolated from acidic Sphagnum peat bogs and were designated OB1010(T), LCBR1, TPB6011(T), TPB6028(T) and TPO1014(T). Cells of these isolates were Gram-negative, non-motile rods that produced an amorphous extracellular polysaccharide-like substance. Old cultures contained spherical bodies of varying sizes, which represent starvation forms. Cells of all five strains were acidophilic and psychrotolerant, capable of growth at pH 3.0-7.5 (optimum pH 3.8-4.5) and at 2-33°C (optimum 15-22°C). The major fatty acids were iso-C(15?:?0), C(16?:?0) and summed feature 3 (C(16?:?1)?7c and/or iso-C(15?:?0) 2-OH). The major menaquinone detected was MK-8. The pigments were carotenoids. The genomic DNA G+C contents were 57.3-59.3 mol%. The five isolates were found to be members of subdivision 1 of the phylum Acidobacteria and displayed 95.3-98.9?% 16S rRNA gene sequence similarity to each other. The closest described relatives to strains OB1010(T), LCBR1, TPB6011(T), TPB6028(T), and TPO1014(T) were members of the genera Terriglobus (94.6-95.8?% 16S rRNA gene sequence similarity) and Edaphobacter (94.2-95.4?%). Based on differences in cell morphology, phenotypic characteristics and hydrolytic capabilities, we propose a novel genus, Granulicella gen. nov., containing four novel species, Granulicella paludicola sp. nov. with type strain OB1010(T) (=DSM 22464(T) =LMG 25275(T)) and strain LCBR1, Granulicella pectinivorans sp. nov. with type strain TPB6011(T) (=VKM B-2509(T) =DSM 21001(T)), Granulicella rosea sp. nov. with type strain TPO1014(T) (=DSM 18704(T) =ATCC BAA-1396(T)) and Granulicella aggregans sp. nov. with type strain TPB6028(T) (=LMG 25274(T) =VKM B-2571(T)). PMID:20118293

  11. Deposition of SOCs in forests

    SciTech Connect

    Horstmann, M.; McLachlan, M.S. [Univ. of Bayreuth (Germany)

    1995-12-31

    The bulk deposition, wet-only deposition, dry-only deposition and ambient air concentrations of PCDD/Fs, PCBs and PAHs were measured in an 80 year old spruce forest, an 80 year old mixed deciduous (beech and oak) forest, and in an adjacent clearing over a period of 1--2 years. The deposition of the less volatile compounds that are primarily particle bound in the atmosphere was similar at both sites. These compounds were deposited primarily through wet deposition, as shown by the measurements in the clearing. In contrast, the deposition of the more volatile compounds was much higher at the forest sites than in the clearing. For instance, the annual deposition of Cl{sub 4}DF was 5 times higher in the spruce forest and 8 times higher in the deciduous forest. The excess deposition in the deciduous forest was almost completely due to the leaf fall in October--December, while about half of the excess deposition in the spruce forest was the result of needle fall. A further, as yet unexplained deposition mechanism accounted for the remainder of the flux in the spruce forest. Other studies have shown that more volatile SOCs are deposited to vegetation primarily through dry gaseous deposition. Hence, while forests have little influence on the deposition of less volatile compounds like the higher chlorinated PCDD/Fs and the 5--6 ring PAHs, dry deposition to leaves/needles and their subsequent falling to the forest floor make forest soils an extremely important sink for more volatile SOC.

  12. Atmospheric Pb deposition since the Industrial Revolution recorded by five Swiss peat profiles: Enrichment factors, fluxes, isotopic composition, and sources

    SciTech Connect

    Weiss, D.; Shotyk, W.; Kramers, J.D. [Univ. of Bern (Switzerland)] [Univ. of Bern (Switzerland); Appleby, P.G. [Univ. of Liverpool (United Kingdom). Dept. of Mathematical Sciences] [Univ. of Liverpool (United Kingdom). Dept. of Mathematical Sciences; Cheburkin, A.K. [Ukrainian Academy of Sciences, Kiev (Ukraine). Inst. of Geological Sciences] [Ukrainian Academy of Sciences, Kiev (Ukraine). Inst. of Geological Sciences

    1999-05-01

    Atmospheric Pb deposition since the Industrial Revolution was studied in western, central, and southern Switzerland using five rural peat bogs. Similar temporal patterns were found in western and central Switzerland, with two distinct periods of Pb enrichment relative to the natural background: between 1880 and 1920 with enrichments ranging from 40 to 80 times, and between 1960 and 1980 with enrichments ranging from 80 to 100 times. The fluxes also were generally elevated in those time periods: in western Switzerland between 1.16 and 1.55 {micro}g cm{sup {minus}2} y{sup {minus}1} during the second period. Between the Industrial Revolution and 1985, nonradiogenic Pb became increasingly important in all five cores because of the replacement of coal by oil after ca. 1920, the use of Australian Pb in industry, and the extensive combustion of leaded gasoline after 1950. The introduction of unleaded gasoline in 1985 had a pronounced effect on the Pb deposition in all five cores. Enrichments dropped sharply, and the isotopic ratios reverted back toward natural values. The cores from western and central Switzerland showed very similar isotopic trends throughout the time period studied, implying that these sites were influenced contemporaneously by similar pollution sources and atmospheric pathways. Southern Switzerland revealed a different record with respect to the Pb pollution: it was dominated by a single massive Pb enrichment dated between 1930 and 1950.

  13. Database of recent tsunami deposits

    USGS Publications Warehouse

    Peters, Robert; Jaffe, Bruce E.

    2010-01-01

    This report describes a database of sedimentary characteristics of tsunami deposits derived from published accounts of tsunami deposit investigations conducted shortly after the occurrence of a tsunami. The database contains 228 entries, each entry containing data from up to 71 categories. It includes data from 51 publications covering 15 tsunamis distributed between 16 countries. The database encompasses a wide range of depositional settings including tropical islands, beaches, coastal plains, river banks, agricultural fields, and urban environments. It includes data from both local tsunamis and teletsunamis. The data are valuable for interpreting prehistorical, historical, and modern tsunami deposits, and for the development of criteria to identify tsunami deposits in the geologic record.

  14. Electrophoretic Deposition for Fabricating Microbatteries

    NASA Technical Reports Server (NTRS)

    West, William; Whitacre, Jay; Bugga, Ratnakumar

    2003-01-01

    An improved method of fabrication of cathodes of microbatteries is based on electrophoretic deposition. Heretofore, sputtering (for deposition) and the use of photoresist and liftoff (for patterning) have been the primary methods of fabricating components of microbatteries. The volume of active electrode material that can be deposited by sputtering is limited, and the discharge capacities of prior microbatteries have been limited accordingly. In addition, sputter deposition is slow. In contrast, electrophoretic deposition is much faster and has shown promise for increasing discharge capacities by a factor of 10, relative to those of microbatteries fabricated by prior methods.

  15. Peat deposits in Panama: Their potential for use in energy applications

    SciTech Connect

    Ramirez, A.; Thayer, G.; Cohen, A.D.; Allen, A.

    1986-12-01

    A major peak bog has been discovered in the Changuinola area of Panama. The bog averages 8-m deep, is thought to be 82 km/sup 2/, in area and the peat has an ash content of about 4%. It is estimated that this size peat bog could support a 30-MW power plant for 360 years. Preliminary cost estimates for using the peat in an electrical power plant give an estimated cost of electricity of 0.09$US/kWh if wet mining is used and 0.079$US/kWh if milled peat is used. 2 refs., 4 figs.

  16. MESOSCOPIC SCALE MODELING FOR CHEMICAL VAPOR DEPOSITION

    E-print Network

    Ringhofer, Christian

    MESOSCOPIC SCALE MODELING FOR CHEMICAL VAPOR DEPOSITION IN SEMICONDUCTOR MANUFACTURING MATTHIAS K. GOBBERT \\Lambda AND CHRISTIAN RINGHOFER y Abstract. Low pressure chemical vapor deposition is a process, homogenization, multiscale modeling, chemical vapor deposition. 1. Introduction. Chemical vapor deposition (CVD

  17. Fluidized Crater Ejecta Deposit

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft continued to obtain high resolution images of the red planet into August 1998. At this time, each ground track (the portion of Mars available for MOC imaging on a given orbit) covers areas from about 40oN on the late afternoon side of the planet, up over the sunlit north polar cap, and down the early morning side of Mars to about 20oN latitude. Early morning and late afternoon views provide good shadowing to reveal subtle details on the martian surface. Views of Mars with such excellent lighting conditions will not be seen by MOC once MGS's Science Phasing Orbits end in mid-September 1998.

    The image shown here, MOC image 47903, was targeted on Friday afternoon (PDT), August 7, 1998. This picture of ejecta from a nameless 9.1 kilometer (5.7 mile)-diameter crater was designed to take full advantage of the present lighting conditions. When the image was taken (around 5:38 p.m. (PDT) on Saturday, August 8, 1998), the Sun had just risen and was only about 6o above the eastern horizon. With the Sun so low in the local sky, the contrast between sunlit and shadowed surfaces allowed new, subtle details to be revealed on the surface of the crater ejecta deposit.

    The crater shown here has ejecta of a type that was first identified in Mariner 9 and Viking Orbiter images as 'fluidized' ejecta. Ejecta is the material that is thrown out from the crater during the explosion that results when a meteor--piece of a comet or asteroid--collides with the planet. Fluidized ejecta is characterized by its lobate appearance, and sometimes by the presence of a ridge along the margin of the ejecta deposit. In the case of the crater shown here, there are two ridges that encircle the crater ejecta--this type of ejecta deposit is sometimes called a double-lobe rampart deposit. The MOC image shows that this particular crater also has 'normal' ejecta that occurs out on the plains, beyond the outermost ridge of the main, fluidized ejecta deposit.

    Fluidized or 'rampart' ejecta deposits have long been thought by many Mars scientists to result from an impact into a surface that contains water. The water would have been underground, and could have been frozen or liquid. According to the prevailing model, when the meteor hit, this water was released--along with tons of rock and debris--and the ejecta flowed like mud. Images with resolutions higher than those presently attainable from the 11.6 hr elliptical orbit are needed to see the specific features (such as large boulders 'rafted' by the dense mud) that would confirm or refute this model. Such images may be acquired once MGS is in its mapping orbit.

    MOC image 47903 was received and processed by the MOC team at Malin Space Science Systems on Monday afternoon (PDT), August 10, 1998. The image center is located at 27.92oN latitude and 184.66oW longitude, in the northern Tartarus Montes region.

  18. Acid Deposition Lab

    NSDL National Science Digital Library

    In this activity students will design an apparatus and carry out tests of fossil fuels to determine their impact on acid deposition by placing a small amount of a fossil fuel on a cotton puff and burning it to measure if acidic compounds are given off. Students will provide a diagram of their collection device and describe how it should function. Students will then draw a map showing the location of their precipitation collector and develop a graph or chart based on the results they have collected.

  19. [Triglyceride deposit cardiomyovasculopathy].

    PubMed

    Hirano, Ken-Ichi

    2013-09-01

    Cholesterol is a vital causal factor and focus of research into heart diseases, however the involvement of triglycerides remains unclear. We recently reported a patient suffering from severe congestive heart failure and needing cardiac transplantation. Massive accumulation of triglycerides was noted in coronary atherosclerotic lesions as well as in the myocardium. We named this phenotype"triglyceride deposit cardiomyovasculopathy (TGCV)". The patient was identified as homozygous for a genetic mutation in the adipose triglyceride lipase (ATGL), an essential molecule for hydrolysis of intracellular triglycerides. In this paper, we describe clinical characteristics of ATGL deficiency and discuss what we can learn from this disorder. PMID:24205734

  20. Geochronology, based on pollen and isotopes, of a Late Glacial gyttja deposit in Vorarlberg, Austria

    NASA Astrophysics Data System (ADS)

    van Mourik, J. M.; Slotboom, R. T.; Streurman, H. J.; van der Plicht, J.; de Graaff, L. W. S.

    2009-04-01

    Geochronology, based on pollen and isotopes, of a Late Glacial gyttja deposit in Vorarlberg, Austria. The Gasserplatz, a peat biotope with histosols, is situated 1 km NE of Feldkirch in Vorarlberg. During the last deglaciation, i.e. the retreat of the Ill glacier by the end of the Oldest Dryas, a tiny ice-marginal lake here developed in a sheltered position at an elevation of 439 m.a.s. After local deglaciation, lacustrine carbonate (chalk gyttja) deposited. At the beginning of the Holocene the lake changed into a peat bog with peat accumulation. The soil archive of the Gasserplatz contains a 6m undisturbed high quality paleoecological record, a sequence of Late Glacial and Holocene deposits. To ‘read' this record we applied pollen and isotope analysis on the Late Glacial lacustrine carbonate deposits. Research on the Gasserplatz profile will be continued by pollen analysis and radiocarbon dating of the Holocene peat deposits. The sedimentation in the former lake started with sterile clay deposition (70 cm) on till. Around 13,000 BP (radiocarbon years) deposition of a 270 cm lacustrine carbonate section started. The deposition rate was rather constant, about 0.85mm per year during almost 3000 years. Peat accumulation started at around 9,500 BP. The pollen diagram of the lake marl deposits shows the vegetation development starting at 13,000 BP. The oldest spectra (535-500 cm) reflect a pioneer vegetation (Artemisia, Helianthemum, Gramineae), followed by invasions of Betula, Juniperus and Pinus. Oscillations in Betula percentages are probably caused by temperature variations. 14C dating of the lake marl deposits is not straightforward. Depending on the source materials (shale's, organic mud, peat) we found different ages at the same depth in the core. Shale's and fibric peat provide the best results for a correct geochronology of the record. ?13C variations show (1) periods without and with biomass production, and (2) qualitative properties of produced biomass. Both are related to temperature. Due to the low concentration of C atoms in water, ? 13C values are very sensitive for system changes. In polar ice cores, d18O variations reflect directly changes in the composition of precipitation, which is a proxy for climatic change. In lacustrine carbonate sediments the d18O values are influenced also by factors like evaporation and lake feeding drain water from the surroundings, but in general the trend in the d18O curve can be correlated with trends in ice cores. Oscillations in the pollen curves (e.g. Betula) and isotope curves of the Gasserplatz core can be correlated. The d18O oscillations of the Gasserplatz core correlate with the polar ice core oscillations and can be used to derive a correct geochronology of the lacustrine carbonate deposits. As a consequence, both pollen and isotopic analysis can be used to reconstruct the evolution of the lake system.

  1. Canyon Floor Deposits

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03598 Canyon Floor Deposits

    The layered and wind eroded deposits seen in this VIS image occur on the floor of Chandor Chasma.

    Image information: VIS instrument. Latitude 5.2S, Longitude 283.4E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Electroless Deposition: Theory and Applications

    NASA Astrophysics Data System (ADS)

    Djoki?, Stojan S.; Cavallotti, Pietro L.

    Electroless deposition is a process that has been used in practice for centuries. Although not recognized as such, electroless deposition of noble metals, e.g., silver or gold was known to the ancient civilizations. In spite of very slow developments throughout the centuries, significant scientific results have been achieved in the second part of the twentieth century. The research achievements in the area of electroless deposition have contributed to tremendous applications and developments in various industries.

  3. Space Station surface deposition monitoring

    NASA Technical Reports Server (NTRS)

    Miller, E. R.

    1988-01-01

    Quartz crystal microbalance sensors are recommended to verify and monitor surface deposition on the early transverse boom as well as the later dual-keel Space Station configurations. Performance and placement of these sensors are discussed and compared to imposed maximum mass deposition rate requirements at the science instrument and critical power locations. Additional measurements are suggested to gain further knowledge on properties of the deposited material.

  4. High soil solution carbon and nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 years of rewetting

    NASA Astrophysics Data System (ADS)

    Frank, S.; Tiemeyer, B.; Gelbrecht, J.; Freibauer, A.

    2014-04-01

    Anthropogenic drainage of peatlands releases additional greenhouse gases to the atmosphere, and dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting drained peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases, over a period of 1 year and a period of 4 months. We chose four sites within one Atlantic bog complex: a near-natural site, two drained grasslands with different mean groundwater levels and a former peat cutting area rewetted 10 years ago. Our results clearly indicate that long-term drainage has increased the concentrations of dissolved organic carbon (DOC), ammonium, nitrate and dissolved organic nitrogen (DON) compared to the near-natural site. DON and ammonium contributed the most to the total dissolved nitrogen. Nitrate concentrations below the mean groundwater table were negligible. The concentrations of DOC and N species increased with drainage depth. In the deeply-drained grassland, with a mean annual water table of 45 cm below surface, DOC concentrations were twice as high as in the partially rewetted grassland with a mean annual water table of 28 cm below surface. The deeply drained grassland had some of the highest-ever observed DOC concentrations of 195.8 ± 77.3 mg L-1 with maximum values of >400 mg L-1. In general, dissolved organic matter (DOM) at the drained sites was enriched in aromatic moieties and showed a higher degradation status (lower DOC to DON ratio) compared to the near-natural site. At the drained sites, the C to N ratios of the uppermost peat layer were the same as of DOM in the peat profile. This suggests that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOM quality through the profile furthermore indicated that DOM moving downwards through the drained sites remained largely biogeochemically unchanged. Unlike DOM concentration, DOM quality and dissolved N species distribution were similar in the two grasslands and thus unaffected by the drainage depth. Methane production during the winter months at the drained sites was limited to the subsoil, which was quasi-permanently water saturated. The recovery of the water table in the winter months led to the production of nitrous oxide around mean water table depth at the drained sites. The rewetted and the near-natural site had comparable DOM quantity and quality (DOC to DON ratio and aromaticity). 10 years after rewetting quasi-pristine biogeochemical conditions have been re-established under continuously water logged conditions in the former peat cut area. Only the elevated dissolved methane and ammonium concentrations reflected the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.

  5. (Acidic deposition and the environment)

    SciTech Connect

    Garten, C.T.; Lindberg, S.E.; Van Miegroet, H.

    1990-10-24

    The travelers presented several papers at the Fourth International Conference on Acidic Deposition. These covered the following topics: atmospheric chemistry and deposition of airborne nitrogen compounds, soil solution chemistry in high-elevation spruce forests, and forest throughfall measurements for estimating total sulfur deposition to ecosystems. In addition, S. E. Lindberg was invited to organize and chair a conference session on Throughfall and Stemflow Experiments, and to present an invited lecture on Atmospheric Deposition and Canopy Interactions of Metals and Nitrogen in Forest Ecosystems: The Influence of Global Change'' at the 110th Anniversary Celebration of the Free University of Amsterdam.

  6. Top-Down Nanomanufacturing: Deposition

    NSDL National Science Digital Library

    This overview of nanotechnology is presented by the NaMCATE project. According to the introductory page, "in related silicon processes for fabrication of MEMS (microelectromechanical devices), deposition of so-called sacrificial layers of oxides or other material are made, and then these layers are removed to free the moving mechanical components from being bonded to the surface." In this module, the various deposition processes are described. Additionally, the module provides three learning activities titled Sputtering Copper, Evaporative Deposition, and Electrochemical Deposition and Chemical Etching. Lastly, a performance assessment and powerpoint presentation are included.Users must create a free login in order to access materials.

  7. Applied depositional modeling for developing western coal deposits

    SciTech Connect

    Mercier, J.M.; Tifft, R.D. III; Vaninetti, G.E.

    1984-07-01

    Geologic data from Mesaverde Group (Upper Cretaceous) strata in the Rocky Mountain region indicate that two major depositional models can be used to evaluate the geology and mining conditions of many western coal deposits. Continentally deposited strata in the roof and floor of coal seams require closely spaced data points for predicting geologically related mining conditions due to the lenticularity of the component beds. Fluvial sandstones are commonly associated with wants, rolls, water inflows, and thinned coal. Channel-margin strata are notorious for roof control problems. Mudstones deposited in interchannel areas are prone to rapid decomposition with the introduction of water, humidity, and stress release. Marine-deposited strata enclosing coal seams require less closely spaced data points than continentally deposited strata for predicting mining conditions because of the lateral continuity of such strata. Roof and floor strata and mining conditions are characteristically uniform over wide areas except near the termination of strata. Shoreline sandstones form very competent roofs and floors although they are locally associated with reduced seam thicknesses. The immediate association of marine-deposited strata and coal commonly results in higher sulfur values at the contacts of these strata. Where marine and continental strata interfinger, the prediction of mining conditions becomes complex and requires an understanding of the depositional and erosive capabilities of the associated facies.

  8. Chemical vapor deposition growth

    NASA Technical Reports Server (NTRS)

    Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

    1976-01-01

    The chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials is investigated. The objective is to develop CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project. Specific areas covered include: (1) modification and test of existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using standard and near-standard processing techniques.

  9. Depositing Diamondlike Carbon Films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Sovey, J. S.; Banks, B. A.

    1986-01-01

    New process demonstrated to make thin films (usually thousands of angstroms to few microns thick) that have properties of diamonds. Various plasma and ion-beam techniques employed to generate films. Films made by radio-frequency plasma decomposition of hydrocarbon gas or other alkanes, by low-energy carbon-ion-beam deposition, or by ion plating and dual ion technique using carbon target. Advantages of new process over others are films produced, though amorphous, are clear, extremely hard, chemically inert, of high resistivity, and have index of refraction of 3.2 properties similar to those of single-crystal diamonds. Films have possible uses in microelectronic applications, high-energy-laser and plastic windows, corrosion protection for metals, and other applications where desired properties of film shaped during the film-formation process.

  10. Nitrogen fixation in boreal peatlands: the effects of increased N deposition on N2-fixation

    NASA Astrophysics Data System (ADS)

    Popma, J. M.; Wieder, R.; Lamers, L.; Vile, M. A.

    2013-12-01

    Boreal peatlands are of great importance to global carbon and nitrogen cycling. While covering only 3-4 % of the terrestrial surface, they account for 25-30 % of the world's soil C and 9-15 % of the world's soil N. In Western Canada atmospheric dry deposition rates are extremely low: approximately 1 kg N ha-1 yr-1. Though these systems have been functioning as net sinks over the past 11,000 years, natural and anthropogenic disturbances might compromise the historical balance of C and N. Biological N2-fixation has recently been shown to represent a very significant input of N into these systems, contributing to 62% of total N in Western Canada. Interactions between N deposition and biological N2-fixation are as yet, unknown, but the impact of elevated deposition of N-compounds from increased industrial expansion of oil sands mining to peatlands, is concerning. Given that nitrogenase, the enzyme responsible for catalyzing N2-fixation, is energetically costly when active, enhanced inputs of atmospheric N deposition could be a major determinant for enzyme activity and rates of biological N input to these bogs. Understanding interactions between N deposition and N2 fixation in boreal peatlands can aid in predicting the consequences of increased N deposition and setting critical loads. We conducted a field-fertilization experiment in a poor fen in Alberta, Canada, to determine the effects of enhanced N deposition on a dominant fen species Sphagnum angustifolium. The experiment consisted of seven N treatments: Control, 0, 5, 10, 15, 20 and 25 kg N ha-1 y1, n=3. N2-fixation was measured during summer 2012 and 2013 using the acetylene reduction assay (ARA). ARA rates were converted to rates of N2-fixation by calibrating ARA with paired 15N2-incubations. In both 2012 and 2013, with increasing N deposition from 0 kg N ha-1 yr-1 to 25 kg N ha-1 yr-1, rates of N2 fixation decreased, with highest rates in the 0 kg N ha-1 yr-1 treatment mosses (54.2 × 1.40; 48.58 × 7.12 kg N ha-1 yr-1, mean × std err for 2012 and 2013, respectively) followed by progressively lower rates with a low of 5.02 × 0.87 in 2012 and 8.94 × 3.09 in 2013 (mean × std err). As biological N2-fixation is an energetically costly process, up-regulating enzyme activity when N availability is low and down-regulating activity when N deposition is enhanced makes thermodynamic and evolutionary sense. N2-fixation shows to be one of the most early-warning indicators to the early response of boreal peatlands to increased N deposition, and can aid in setting critical loads to protect these historically pristine ecosystems.

  11. Variable temperature semiconductor film deposition

    DOEpatents

    Li, X.; Sheldon, P.

    1998-01-27

    A method of depositing a semiconductor material on a substrate is disclosed. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  12. Physical vapor deposition tool coatings

    Microsoft Academic Search

    William D. Sproul

    1996-01-01

    Physical vapor deposition (PVD) of hard coatings such as titanium nitride have been an industrial reality since the beginning of the 1980s. Two PVD processes, low voltage electron beam and cathodic arc deposition, were responsible for the early commercial success of hard coatings on high speed steel tooling. Since that time, two other PVD processes have also been prosperous in

  13. Variable temperature semiconductor film deposition

    DOEpatents

    Li, Xiaonan (Golden, CO); Sheldon, Peter (Lakewood, CO)

    1998-01-01

    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  14. SOIL REACTION AND ACIDIC DEPOSITION

    EPA Science Inventory

    This chapter discusses the major chemical processes by which acidic deposition interacts with soils. he focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of agricultural practices s...

  15. Deposited films with improved microstructures

    DOEpatents

    Patten, James W. (Richland, WA); Moss, Ronald W. (Richland, WA); McClanahan, Edwin D. (Richland, WA)

    1984-01-01

    Methods for improving microstructures of line-of-sight deposited films are described. Columnar growth defects ordinarily produced by geometrical shadowing during deposition of such films are eliminated without resorting to post-deposition thermal or mechanical treatments. The native, as-deposited coating qualities, including homogeneity, fine grain size, and high coating-to-substrate adherence, can thus be retained. The preferred method includes the steps of emitting material from a source toward a substrate to deposit a coating non-uniformly on the substrate surface, removing a portion of the coating uniformly over the surface, again depositing material onto the surface, but from a different direction, and repeating the foregoing steps. The quality of line-of-sight deposited films such as those produced by sputtering, progressively deteriorates as the angle of incidence between the flux and the surface becomes increasingly acute. Depositing non-uniformly, so that the coating becomes progressively thinner as quality deteriorates, followed by uniformly removing some of the coating, such as by resputtering, eliminates the poor quality portions, leaving only high quality portions of the coating. Subsequently sputtering from a different direction applies a high quality coating to other regions of the surface. Such steps can be performed either simultaneously or sequentially to apply coatings of a uniformly high quality, closed microstructure to three-dimensional or large planar surfaces.

  16. Tritium deposition patterns in TFTR

    E-print Network

    Princeton Plasma Physics Laboratory

    Tritium deposition patterns in TFTR Presented by C. H. Skinner with key contributions from Charles, JAERI #12;· TFTR was a limiter machine - no divertor. · Operated with tritium Nov `93 - April `97. · NetV Limiter Temperature @ 28 MW NBI Low density, high temperature edge #12;Tritium deposition patterns in TFTR

  17. Environmental Studies of Mineral Deposits in Alaska

    NSDL National Science Digital Library

    1996-01-01

    This collection of articles summarizes environmental geochemical studies of metallic mineral deposits in Alaska, including sulfide, gold, mercury, chromium, and uranium mines and deposits. The studies report metal and acid concentrations in samples collected around such mines and deposits, and evaluate environmental effects of the deposits. An introduction explains geochemical processes, how metals enter environments downstream from mineral deposits, and background geochemical studies. Other articles are: Studies of Mineral Deposits Rich in Heavy Metals; Environmental Geochemistry of Mercury Mines in Southwestern Alaska; Environmental Geochemistry of Alaskan Gold Deposits; Geochemistry of Surface Waters Draining Alaskan Chromite Deposits; and Radioactivity Concerns of Uranium and Thorium Deposits at Bokan Mountain, Southeastern Alaska.

  18. Ni-Co laterite deposits

    USGS Publications Warehouse

    Marsh, Erin E.; Anderson, Eric D.

    2011-01-01

    Nickel-cobalt (Ni-Co) laterite deposits are an important source of nickel (Ni). Currently, there is a decline in magmatic Ni-bearing sulfide lode deposit resources. New efforts to develop an alternative source of Ni, particularly with improved metallurgy processes, make the Ni-Co laterites an important exploration target in anticipation of the future demand for Ni. This deposit model provides a general description of the geology and mineralogy of Ni-Co laterite deposits, and contains discussion of the influences of climate, geomorphology (relief), drainage, tectonism, structure, and protolith on the development of favorable weathering profiles. This model of Ni-Co laterite deposits represents part of the U.S. Geological Survey Mineral Resources Program's effort to update the existing models to be used for an upcoming national mineral resource assessment.

  19. Improving the 210Pb-chronology of Pb deposition in peat cores from Chao de Lamoso (NW Spain).

    PubMed

    Olid, Carolina; Garcia-Orellana, Jordi; Masqué, Pere; Cortizas, Antonio Martínez; Sanchez-Cabeza, Joan Albert; Bindler, Richard

    2013-01-15

    The natural radionuclide (210)Pb is commonly used to establish accurate and precise chronologies for the recent (past 100-150 years) layers of peat deposits. The most widely used (210)Pb-dating model, Constant Rate of Supply (CRS), was applied using data from three peat cores from Chao de Lamoso, an ombrotrophic mire in Galicia (NW Spain). On the basis of the CRS-chronologies, maximum Pb concentrations and enrichment factors (EFs) occurred in the 1960s and late 1970s, consistent with the historical use of Pb. However, maximum Pb fluxes were dated in the 1940s and the late 1960s, 10 to 20 years earlier. Principal component analysis (PCA) showed that, although the (210)Pb distribution was mainly (74%) controlled by radioactive decay, about 20% of the (210)Pb flux variability was associated with atmospheric metal pollution, suggesting an extra (210)Pb supply source and thus invalidating the main assumption of the CRS model. When the CRS-ages were recalculated after correcting for the extra input from the (210)Pb inventory of the uppermost peat layers of each core, Pb flux variations were consistent with the historical atmospheric Pb deposition. Our results not only show the robustness of the CRS model to establish accurate chronologies of recent peat deposits but also provide evidence that there are confounding factors that might influence the calculation of reliable peat accumulation rates (and thus also element accumulation rates/fluxes). This study emphasizes the need to verify the hypotheses of (210)Pb-dating models and the usefulness of a full geochemical interpretation of peat bog records. PMID:23220752

  20. Vacuum vapor deposition

    NASA Technical Reports Server (NTRS)

    Poorman, Richard M. (inventor); Weeks, Jack L. (inventor)

    1995-01-01

    A method and apparatus is described for vapor deposition of a thin metallic film utilizing an ionized gas arc directed onto a source material spaced from a substrate to be coated in a substantial vacuum while providing a pressure differential between the source and the substrate so that, as a portion of the source is vaporized, the vapors are carried to the substrate. The apparatus includes a modified tungsten arc welding torch having a hollow electrode through which a gas, preferably inert, flows and an arc is struck between the electrode and the source. The torch, source, and substrate are confined within a chamber within which a vacuum is drawn. When the arc is struck, a portion of the source is vaporized and the vapors flow rapidly toward the substrate. A reflecting shield is positioned about the torch above the electrode and the source to ensure that the arc is struck between the electrode and the source at startup. The electrode and the source may be confined within a vapor guide housing having a duct opening toward the substrate for directing the vapors onto the substrate.

  1. Hydrothermal alteration of organic matter in uranium ores, Elliot Lake, Canada: Implications for selected organic-rich deposits

    SciTech Connect

    Mossman, D.J. [Mount Allison Univ., Sackville (Canada)] [Mount Allison Univ., Sackville (Canada); Nagy, B. [Univ. of Arizona, Tucson (United States)] [Univ. of Arizona, Tucson (United States); Davis, D.W. [Royal Ontario Museum, Toronto, Ontario (Canada)] [Royal Ontario Museum, Toronto, Ontario (Canada)

    1993-07-01

    Organic matter in the uraniferous Matinenda Formation, Elliot Lake, is preserved in the forms of syngenetic kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium ores. The Elliot Lake kerogen is a vitrinite-like material considered to be remnants of the Precambrian cyanobacterial mats. The kerogen at Elliot Lake has reflectances (in oil) ranging from 2.63-7.31% RO{sub max}, high aromaticity, relatively low (0.41-0.60) atomic H/C ratios, and it contains cryptocrystalline graphite. Bitumen, present primarily as dispersed globules (up to 0.5 mm dia.), has reflectances from 0.72-1.32% RO{sub max}, atomic H/C ratios of 0.71-0.81, and is somewhat less aromatic than the kerogen. Overall similarity in molecular compositions indicates that liquid bitumen was derived from kerogen by processes similar to hydrous pyrolysis. The carbon isotopic composition of kerogen ({minus}15.62 to {minus}24.72%), and the now solid bitumen ({minus}25.91 to {minus}33.00%) are compatible with these processes. Despite having been subjected to several thermal episodes, ca. 2.45 Ga old kerogen of microbiological origin here survived as testimony of the antiquity of life on Earth. U-Pb isotopic data from discrete kerogen grains at Elliot Lake form a scattered array intersecting concordia at 2130 {+-} 100 Ma, correspond to the Nipissing event. U-Pb systems were totally reset by this event. Uranium and lead show subsequently partial mobility, the average of which is indicated by the lower concordia intersect of 550 {+-} 260 Ma. The migrated bitumen contains virtually no uranium and thorium but has a large excess of {sup 206}Pb, which indicates that the once liquid bitumen must have acted as a sink for mobile intermediate decay products of {sup 238}U. Emplacement of the Nipissing diabase may have been responsible for producing the bitumen and, indirectly, for its enrichment in {sup 206}Pb as a result of outgassing of {sup 222}Rn.

  2. 12 CFR 19.170 - Discovery depositions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Discovery depositions. 19.170...PRACTICE AND PROCEDURE Discovery Depositions and Subpoenas § 19.170 Discovery depositions. (a) General...party, who has direct knowledge of matters that...

  3. 7 CFR 1.148 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...manner of the deposition (telephone, audio-visual telecommunication, or personal...determines that conducting the deposition by audio-visual telecommunication: (i) Is...determines that a deposition conducted by audio-visual telecommunication would...

  4. 01-01-2014 Return Deposit Form Return Deposit Form

    E-print Network

    Hutcheon, James M.

    and return the Deposit Return Form with the social security number, and address. Once this form is received:____________________________________________________________________ Phone: _________________________________________________________________ Social Security Number photos) for use by the Garden in describing previous private events for publications, promotion and web

  5. Atmospheric Mercury Deposition Monitoring ? National Atmospheric Deposition Program (NADP)

    EPA Science Inventory

    The National Atmospheric Deposition Program (NADP) developed and operates a collaborative network of atmospheric mercury monitoring sites based in North America ? the Atmospheric Mercury Network (AMNet). The justification for the network was growing interest and demand from many ...

  6. Particle deposition in ventilation ducts

    SciTech Connect

    Sippola, Mark R.

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 {micro}m were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the experimental measurements was applied to evaluate particle losses in supply and return duct runs. Model results suggest that duct losses are negligible for particle sizes less than 1 {micro}m and complete for particle sizes greater than 50 {micro}m. Deposition to insulated ducts, horizontal duct floors and bends are predicted to control losses in duct systems. When combined with models for HVAC filtration and deposition to indoor surfaces to predict the ultimate fates of particles within buildings, these results suggest that ventilation ducts play only a small role in determining indoor particle concentrations, especially when HVAC filtration is present. However, the measured and modeled particle deposition rates are expected to be important for ventilation system contamination.

  7. Deposition + Erosion = Textures

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 7 May 2003

    Toward the westernmost extent of the Medusae Fossae Formation, a 5000+ km long belt of eroding sediments, the interleaving of erosional surfaces produces dramatic textural variations. In the lower third of this image, the cross-hatched MFF layer is being stripped back from a surface that was already heavily eroded before the MFF layer was deposited. Also, note the sinuous and, in places, dendritic ridges that are either linear dunes or inverted channels.

    Image information: VIS instrument. Latitude -3.9, Longitude 154.1East (205.9). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Vapor deposition of hardened niobium

    DOEpatents

    Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)

    1983-04-19

    A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

  9. Chemical enhancement of surface deposition

    DOEpatents

    Patch, Keith D. (Lexington, MA); Morgan, Dean T. (Sudbury, MA)

    1997-07-29

    A method and apparatus for increasing the deposition of ions onto a surface, such as the adsorption of uranium ions on the detecting surface of a radionuclide detector. The method includes the step of exposing the surface to a complexing agent, such as a phosphate ion solution, which has an affinity for the dissolved species to be deposited on the surface. This provides, for example, enhanced sensitivity of the radionuclide detector.

  10. Chemical enhancement of surface deposition

    DOEpatents

    Patch, K.D.; Morgan, D.T.

    1997-07-29

    A method and apparatus are disclosed for increasing the deposition of ions onto a surface, such as the adsorption of uranium ions on the detecting surface of a radionuclide detector. The method includes the step of exposing the surface to a complexing agent, such as a phosphate ion solution, which has an affinity for the dissolved species to be deposited on the surface. This provides, for example, enhanced sensitivity of the radionuclide detector. 16 figs.

  11. A Radon Progeny Deposition Model

    SciTech Connect

    Guiseppe, V. E. [University of South Dakota, Vermillion, South Dakota 57069 (United States); Elliott, S. R.; Hime, A.; Rielage, K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Westerdale, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2011-04-27

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly {sup 222}Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of {sup 210}Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

  12. A Radon Progeny Deposition Model

    E-print Network

    V. E. Guiseppe; S. R. Elliott; A. Hime; K. Rielage; S. Westerdale

    2010-12-30

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly Rn-222) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of Pb-210 on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

  13. A radon progeny deposition model

    SciTech Connect

    Rielage, Keith [Los Alamos National Laboratory; Elliott, Steven R [Los Alamos National Laboratory; Hime, Andrew [Los Alamos National Laboratory; Guiseppe, Vincente E [Los Alamos National Laboratory; Westerdale, S. [MIT

    2010-12-01

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly {sup 222}Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of {sup 210}Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

  14. Impact of subjacent rocks at the water and air regime of the depleted peat deposits

    NASA Astrophysics Data System (ADS)

    Rakovich, V. A.

    2009-04-01

    At the depleted peat deposits (after peat extraction), where the residual layer of peat with the thickness of about 0,5 meters is laid at the well water permeable rocks, vegetation typical for dry conditions is developed in case of good drainage conditions; birch trees, willow, alder-trees and buckthorn prevail in this vegetation. Water and air regime is characterized here by good aeration with prevailing of oxidative processes. If water regime is regulated, these depleted peat areas are suitable for agricultural and forest lands; however, necessity of transformation of these depleted lands into forest and agricultural lands must be ecologically and economically justified. If the residual layer of peat with the thickness of 0,05-0,3 m is based at the sapropel or peat sapropel, contrast amphibiotic water and air regime with strong fluctuation of oxidative and restoration process depending on the weather conditions is formed; this regime is formed without artificial increase of the ground waters level. This does not allow bog vegetation or vegetation typical for dry conditions to develop. Thus, within 20 and more years after completion of peat extraction, such areas are not covered by vegetation in spite of favorable agro-chemical qualities of peat layer and favorable for vegetation chemical composition of soil and ground waters. Depleted peat deposits, that are based at the sapropel, are not suitable for agricultural use, because agricultural vegetation requires stable water and air regime with good aeration and oxidative and restoration potential within 400-750 mV. Contrast amphibiotic water and air regime of the depleted peat deposits that are based at sapropel excludes possibility to use them as agricultural lands. Because of this reason, areas with residual peat layer that are based at sapropel are not suitable for forest planting. Due to periodic increase of ground waters level, rot systems of the plants can not penetrate into the required depth, and mechanical solidity of the residual low-powered peat layer does not facilitate formation of wind stable plats. Besides, due to the fact that this territory was formed at the place of former ancient lake, there is a possibility that this territory will be flooded during water full periods for long periods because columbine from the nearby territories and this will lead to the death of forest plants. It is more profitable to use these areas for re-wetting or for creation of water basins.

  15. U-Pb SHRIMP dating of uraniferous opals

    USGS Publications Warehouse

    Nemchin, A.A.; Neymark, L.A.; Simons, S.L.

    2006-01-01

    U-Pb and U-series analyses of four U-rich opal samples using sensitive high-resolution ion microprobe (SHRIMP) demonstrate the potential of this technique for the dating of opals with ages ranging from several tens of thousand years to millions of years. The major advantages of the technique, compared to the conventional thermal ionisation mass spectrometry (TIMS), are the high spatial resolution (???20 ??m), the ability to analyse in situ all isotopes required to determine both U-Pb and U-series ages, and a relatively short analysis time which allows obtaining a growth rate of opal as a result of a single SHRIMP session. There are two major limitations to this method, determined by both current level of development of ion probes and understanding of ion sputtering processes. First, sufficient secondary ion beam intensities can only be obtained for opal samples with U concentrations in excess of ???20 ??g/g. However, this restriction still permits dating of a large variety of opals. Second, U-Pb ratios in all analyses drifted with time and were only weakly correlated with changes in other ratios (such as U/UO). This drift, which is difficult to correct for, remains the main factor currently limiting the precision and accuracy of the U-Pb SHRIMP opal ages. Nevertheless, an assumption of similar behaviour of standard and unknown opals under similar analytical conditions allowed successful determination of ages with precisions of ???10% for the samples investigated in this study. SHRIMP-based U-series and U-Pb ages are consistent with TIMS dating results of the same materials and known geological timeframes. ?? 2005 Elsevier B.V. All rights reserved.

  16. Geochemical evolution of uraniferous soda lakes in Eastern Mongolia

    Microsoft Academic Search

    Benjamin S. LinhoffPhilip; Philip C. Bennett; Tamir Puntsag; Ochir Gerel

    2011-01-01

    Extremely high concentrations of uranium (U) were discovered in shallow, groundwater-fed hyperalkaline soda lakes in Eastern\\u000a Mongolia. A representative groundwater sample in this area is dilute and alkaline, pH = 7.9, with 10 mM TIC and 5 mM Cl?. In contrast, a representative lake water sample is pH ~ 10 with TIC and Cl? each more than 1,000 mM. Groundwater concentrations of U range from 0.03 to

  17. Deposition and clearance of inhaled particles

    Microsoft Academic Search

    1984-01-01

    Theoretical models of respiratory tract deposition of inhaled particles are compared to experimental studies of deposition patterns in humans and animals, as governed principally by particle size, density, respiratory rate and flow parameters. Various models of inhaled particle deposition make use of approximations of the respiratory tract to predict fractional deposition caused by fundamental physical processes of particle impaction, sedimentation,

  18. Electrophoretic deposition forming of porous alumina membranes

    Microsoft Academic Search

    C.-Y. Chen; S.-Y. Chen; D.-M. Liu

    1999-01-01

    An electrophoretic deposition (EPD) technique is used to prepare porous alumina membranes. The deposition kinetics which are conventionally derived based on a mass conservation law have been modified in terms of the thickness of the deposited layer. This modification allows the porosity evolution of the membrane to be predicted under a variety of EPD processes. A transition in deposition from

  19. 12 CFR 337.6 - Brokered deposits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (F) The trustee of a testamentary account; (G) The trustee...deposits of comparable size and maturity in such institution's normal...deposits of comparable size and maturity for deposits accepted outside...insured deposits of comparable maturity in such institution's...

  20. Induction of indirect N2O and NO emissions by atmospheric nitrogen deposition in (semi-)natural ecosystems in Switzerland

    NASA Astrophysics Data System (ADS)

    Bühlmann, Tobias; Hiltbrunner, Erika; Körner, Christian; Rihm, Beat; Achermann, Beat

    2015-02-01

    During the past century atmospheric nitrogen deposition increased dramatically due to human activities worldwide. Currently, it exceeds the critical load for nitrogen (CLN) in over 90% of the Swiss forest area and raised bogs, in 80% of all fens and in 30% of species-rich grassland areas in Switzerland. Indirect gaseous nitrogen losses (HNO2, NO, N2O, N2) from these soils induced by atmospheric nitrogen deposition are likely to be substantial. However, the approaches to estimate these indirect N emissions provided by the international organisations (UNFCCC, IPCC; UNECE, EMEP/EEA) are based on agricultural data only. They may not be suitable to estimate the indirect emissions from (semi-)natural ecosystems such as forests, extensively used grassland, and wetlands. The present study aims at calculating ecosystem-specific annual indirect N2O and NO emissions of (semi-)natural ecosystems in Switzerland for the years 1990, 2000, 2007 and 2010 using a simple linear model similar to the international guidelines. The approach here is based on empirical data for (semi-)natural ecosystems, derived from a literature survey, is driven by atmospheric nitrogen deposition and is ecosystem-specific with a high spatial resolution of 100 m × 100 m. Our results show that such ecosystems represent a strong source of indirect N emissions induced by atmospheric nitrogen deposition and emitted 1.61 ± 0.32 Gg N2O-N and 2.51 ± 0.53 Gg NO-N into the atmosphere in Switzerland in the year 2010, corresponding to 21% of the total Swiss N2O emissions and 10% of the NOx emissions. Thanks to the reduction of N emissions and thereby reduced atmospheric N deposition, the indirect N2O and NO emissions from (semi-)natural ecosystems are estimated to have been both reduced by c. 20% from 1990 to 2010. We conclude that the source strength for N2O and NO emissions of (semi-)natural ecosystems have been underestimated by the current approaches of IPCC and EMEP/EEA by a factor of 4.4 and 17, respectively. In regions and countries with a high fraction of (semi-)natural ecosystems, the approach offered here has the potential to improve the estimate of indirect N emissions substantially.

  1. Simultaneous ion sputter polishing and deposition

    NASA Technical Reports Server (NTRS)

    Rutledge, S.; Banks, B.; Brdar, M.

    1981-01-01

    Results of experiments to study ion beam sputter polishing in conjunction with simultaneous deposition as a mean of polishing copper surfaces are presented. Two types of simultaneous ion sputter polishing and deposition were used in these experiments. The first type utilized sputter polishing simultaneous with vapor deposition, and the second type utilized sputter polishing simultaneous with sputter deposition. The etch and deposition rates of both techniques were studied, as well as the surface morphology and surface roughness.

  2. Chemical vapor deposition and atomic layer deposition of metal oxide and nitride thin films

    Microsoft Academic Search

    Jeffrey Thomas Barton

    2003-01-01

    Processes for depositing thin films with various electronic, optical, mechanical, and chemical properties are indispensable in many industries today. Of the many deposition methods available, chemical vapor deposition (CVD) has proved over time to be one of the most flexible, efficient, and cost-effective. Atomic layer deposition (ALD) is a newer process that is gaining favor as a method for depositing

  3. Io - A surface evaporite deposit

    NASA Technical Reports Server (NTRS)

    Fanale, F. P.; Johnson, T. V.; Matson, D. L.

    1974-01-01

    A model is suggested for Io's surface composition involving evaporite salt deposits, rich in sodium and sulfur. According to this model, these deposits were produced as a result of the migration of salt-saturated aqueous solutions to Io's surface from a warm or hot interior followed by loss of the water to space. This model satisfies cosmochemical constraints based on Io's initial composition, current density, and thermal history. Salt-rich assemblages are easily derivable from the leaching of carbonaceous chondritic material. The chemical and optical properties of such deposits, after modification by irradiation, can be used to explain Io's overall albedo and spectral reflectance, its dark reddish poles, and the observed sodium emission as well as or better than other currently suggested materials.

  4. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R. (Los Alamos, NM); Carroll, David W. (Los Alamos, NM); Trkula, Mitchell (Los Alamos, NM); Anderson, Wallace E. (Los Alamos, NM); Valone, Steven M. (Santa Fe, NM)

    1998-01-01

    A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

  5. Vapor deposition of thin films

    DOEpatents

    Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  6. Suspected endothelial pencil graphite deposition.

    PubMed

    Gül, Adem; Can, Ertu?rul; Yücel, Ozlem E?ki; Niyaz, Leyla; Akgün, Halil ?brahim; Ar?türk, Nur?en

    2013-01-01

    A 14-year-old male patient had an ocular trauma with a pencil. Biomicroscopic examination revealed a broken part of pencil into the cornea. Foreign body removal and corneal wound closure were performed in the same day. After corneal repair, there was a grade 4+ anterior chamber reaction just like in preoperative examination. Dilated examination showed a very small piece broken tip of pencil on the upper nasal quadrant of the lens. A small and linear deposition was also seen on endothelial surface. Endothelial deposition and foreign body disappeared with intensive topical steroid treatment. PMID:24392234

  7. Suspected Endothelial Pencil Graphite Deposition

    PubMed Central

    Gül, Adem; Can, Ertu?rul; Yücel, Özlem E?ki; Niyaz, Leyla; Akgün, Halil ?brahim; Ar?türk, Nur?en

    2013-01-01

    A 14-year-old male patient had an ocular trauma with a pencil. Biomicroscopic examination revealed a broken part of pencil into the cornea. Foreign body removal and corneal wound closure were performed in the same day. After corneal repair, there was a grade 4+ anterior chamber reaction just like in preoperative examination. Dilated examination showed a very small piece broken tip of pencil on the upper nasal quadrant of the lens. A small and linear deposition was also seen on endothelial surface. Endothelial deposition and foreign body disappeared with intensive topical steroid treatment. PMID:24392234

  8. Observe how sediments are deposited

    NSDL National Science Digital Library

    TERC. Center for Earth and Space Science Education

    2003-01-01

    This interactive Earth science visualization for middle and high school students illustrates the order in which sediments of different sizes are deposited by a river as it flows into a lake. A short animation accompanied by text boxes demonstrates that as stream flow progressively lessens, large sediments like gravel are the first to drop out and be deposited, followed by sand sediments, and finally by smaller clay-sized sediments. Students are able to use control buttons to play, pause and move forward and backward through the simulation. Copyright 2005 Eisenhower National Clearinghouse

  9. Soot Deposit Properties in Practical Flames

    SciTech Connect

    Preciado, Ignacio [University of Utah; Eddings, Eric G. [University of Utah; Sarofim, Adel F. [University of Utah; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL

    2009-01-01

    Soot deposition from hydrocarbon flames was investigated in order to evaluate the evolution of the deposits during the transient process of heating an object that starts with a cold metal surface that is exposed to a flame. The study focused on the fire/metal surface interface and the critical issues associated with the specification of the thermal boundaries at this interface, which include the deposition of soot on the metal surface, the chemical and physical properties of the soot deposits and their subsequent effect on heat transfer to the metal surface. A laboratory-scale device (metallic plates attached to a water-cooled sampling probe) was designed for studying soot deposition in a laminar ethylene-air premixed flame. The metallic plates facilitate the evaluation of the deposition rates and deposit characteristics such as deposit thickness, bulk density, PAH content, deposit morphology, and thermal properties, under both water-cooled and uncooled conditions. Additionally, a non-intrusive Laser Flash Technique (in which the morphology of the deposit is not modified) was used to estimate experimental thermal conductivity values for soot deposits as a function of deposition temperature (water-cooled and uncooled experiments), location within the flame and chemical characteristics of the deposits. Important differences between water-cooled and uncooled surfaces were observed. Thermophoresis dominated the soot deposition process and enhanced higher deposition rates for the water-cooled experiments. Cooler surface temperatures resulted in the inclusion of increased amounts of condensable hydrocarbons in the soot deposit. The greater presence of condensable material promoted decreased deposit thicknesses, larger deposit densities, different deposit morphologies, and higher thermal conductivities.

  10. Global Climate Change Earth system science

    E-print Network

    Pan, Feifei

    , current, and future #12; Sediments deposited on floodplains or in lakes, bogs, glaciers, or the ocean may, bogs, and lakes. Scientists study the abundance and types of pollen in order to investigate past

  11. An Oligocene subaqueous PDC deposit: inferences on its depositional mechanisms

    NASA Astrophysics Data System (ADS)

    Di Capua, A.; Groppelli, G.

    2014-12-01

    We studied and discussed the depositional mechanisms of a PDC deposit recognized in the Oligocene turbite system of the Val d'Aveto Formation (Northern Italian Apennines). The deposit is characterized by a sandy-sized base (4 m-thick), overlain by a massive conglomerate (46 m-thick), whose gravel-sized detritus is overall represented by substrate-derived clasts (~80%), rather than volcaniclastic ones. Optical, diffractometric (XRD) and minero-chemical (SEM-EDS) analyses on matrix samples reveal a welded volcanic felty texture, rich in plagioclase and horneblende, with accidental metamorphic rock fragments and loose crystals that tend to upward increase along the deposit. Lithological association and roundness of gravel-sized detritus, together with the accidental lithics and loose crystals in the matrix fraction, suggest that this PDC ran channelized in a continental (mountain?) drainage before entering the basin. Channelization in this type of setting 1) enhanced the PDC erosion capacity during the motion and 2) partially cooled it. Flow reached the water at temperatures which triggered the formation of a trapped gas carapace, able to inhibit the water-flow mixing (Sparks et al. (1980-Journal of Volcanology and Geothermal Research). This preserved the current from a shocking water mix and favored its welding. Thus, we suggest that this model can be generally applied when PDC temperatures trigger a stable heat transfer between the flow and the water, which allows the generation of trapped gas carapace and preservation from phreatomagmatic explosions. In contrast, depositional mechanisms inferred by Whitman (1989-Marine Geology) and the ones proposed through the direct observation and sampling of a hot PDC at Montserrat Volcano (Trofimovs et al., 2006-Geology) are developed when fundamental role is played by phreatomagmatic explosions and violent water-flow mix.

  12. Minimizing iron and copper deposition

    Microsoft Academic Search

    1975-01-01

    A major cause of tube failures in high-pressure subcritical boilers is uncontrolled deposition of corrosion products in internal tube surfaces. The predominant corrosion products are iron oxides, copper, and copper oxides. A water treatment program that controls corrosion products can increase availability and reliability by reducing tube failures and acid cleaning frequency. Such a program includes corrosion product dispersion in

  13. The Guaranty of Bank Deposits

    E-print Network

    Hopper, E.B.

    1913-06-01

    in that the sound banks must then pay the losses of the poor banksi that the cost of prem­ ium is more than the benefits derivedi that it is a double tax on bankers deposits} that the risk of any one bank can­ not be limited and that it involves too much...

  14. Grow Your Own Copper Deposit

    ERIC Educational Resources Information Center

    Corcoran, Timothy John

    2009-01-01

    Crystals are beautiful structures--yet they occur naturally in dirty and remote places. In the inquiry-based activity described here, students will enjoy the process of creating their own crystals and using microscopes to examine them. It demonstrates the process of mineral concentration and deposition. Upon completing this activity, students…

  15. CLIMATE CHANGE AND N DEPOSITION

    EPA Science Inventory

    This project investigates the potential influence of climate change on wet deposition of reduced nitrogen across the U.S. The concentration of ammonium-nitrogen in precipitation is known to increase with temperature, owing to temperature dependent ammonia source strengths (natur...

  16. Electro-spark deposition technology

    SciTech Connect

    Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

  17. CASTNET ANNUAL, QUARTERLY, WEEKLY DEPOSITION

    EPA Science Inventory

    A zip file containing 7 files: castnet.gif: map of CASTNet sites sites.zip: site information for all sites, including geographic information and current operating status velan.zip: annual dry deposition flux rates, velocities, and concentrations for all sites as estimate...

  18. Electrochemical Deposition Of Conductive Copolymers

    NASA Technical Reports Server (NTRS)

    Nagasubramanian, Ganesan; Distefano, Salvador; Liang, Ranty H.

    1991-01-01

    Experiments show electrically conductive films are deposited on glassy carbon or indium tin oxide substrates by electrochemical polymerization of N-{(3-trimethoxy silyl) propyl} pyrrole or copolymerization with pyrrole. Copolymers of monomer I and pyrrole exhibit desired electrical conductivity as well as desired adhesion and other mechanical properties. When fully developed, new copolymerization process useful in making surface films of selectable conductivity.

  19. Simple Chemical Vapor Deposition Experiment

    ERIC Educational Resources Information Center

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  20. Vacuum vapor deposition gun assembly

    DOEpatents

    Zeren, Joseph D. (Boulder, CO)

    1985-01-01

    A vapor deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, a hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  1. Advanced deposition model for thermal activated chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface reactions on the substrate surface, conductive, convective, inductive and radiative heat transfer, species transport and thereto-elastic stress distributions. Gas phase and surface reactions are studied thermodynamically and kinetically. Based on experimental results, detailed reaction mechanisms are proposed and the deposition rates are predicted. The deposition model proposed could be used for other experiments with similar operating conditions. Four different growth systems are presented in this thesis to discuss comprehensive transport phenomena in crystal growth from vapor. The first is the polysilicon bulk growth by modified Siemens technique in which a silicon tube is used as the starting material. The research effort has been focused on system design, geometric and operating parameters optimization, and heterogeneous and homogeneous silane pyrolysis analysis. The second is the GaN thin film growth by iodine vapor phase epitaxy technique. Heat and mass transport is studied analytically and numerically. Gas phase and surface reactions are analyzed thermodynamically and kinetically. Quasi-equilibrium and kinetic deposition models are developed to predict the growth rate. The third one is the AlN thin film growth by halide vapor phase epitaxy technique. The effects of gas phase and surface reactions on the crystal growth rate and deposition uniformity are studied. The last one is the AlN sublimation growth system. The research effort has been focused on the effect of thermal environment evolution on the crystal growth process. The thermoelastic stress formed in the as-grown AlN crystal is also calculated.

  2. Elucidating effects of atmospheric deposition and peat decomposition processes on mercury accumulation rates in a northern Minnesota peatland over last 10,000 cal years

    NASA Astrophysics Data System (ADS)

    Nater, E. A.; Furman, O.; Toner, B. M.; Sebestyen, S. D.; Tfaily, M. M.; Chanton, J.; Fissore, C.; McFarlane, K. J.; Hanson, P. J.; Iversen, C. M.; Kolka, R. K.

    2014-12-01

    Climate change has the potential to affect mercury (Hg), sulfur (S) and carbon (C) stores and cycling in northern peatland ecosystems (NPEs). SPRUCE (Spruce and Peatland Responses Under Climate and Environmental change) is an interdisciplinary study of the effects of elevated temperature and CO2 enrichment on NPEs. Peat cores (0-3.0 m) were collected from 16 large plots located on the S1 peatland (an ombrotrophic bog treed with Picea mariana and Larix laricina) in August, 2012 for baseline characterization before the experiment begins. Peat samples were analyzed at depth increments for total Hg, bulk density, humification indices, and elemental composition. Net Hg accumulation rates over the last 10,000 years were derived from Hg concentrations and peat accumulation rates based on peat depth chronology established using 14C and 13C dating of peat cores. Historic Hg deposition rates are being modeled from pre-industrial deposition rates in S1 scaled by regional lake sediment records. Effects of peatland processes and factors (hydrology, decomposition, redox chemistry, vegetative changes, microtopography) on the biogeochemistry of Hg, S, and other elements are being assessed by comparing observed elemental depth profiles with accumulation profiles predicted solely from atmospheric deposition. We are using principal component analyses and cluster analyses to elucidate relationships between humification indices, peat physical properties, and inorganic and organic geochemistry data to interpret the main processes controlling net Hg accumulation and elemental concentrations in surface and subsurface peat layers. These findings are critical to predicting how climate change will affect future accumulation of Hg as well as existing Hg stores in NPE, and for providing reference baselines for SPRUCE future investigations.

  3. Effect of deposition temperature on the characteristics of Zinc Oxide nanoparticles thin films deposited by thermal chemical vapor deposition

    Microsoft Academic Search

    S. S. Shariffudin; N. Z. Zakaria; S. H. Herman; M. Rusop

    2011-01-01

    Zinc Oxide (ZnO) thin films were deposited by thermal chemical vapor deposition (TCVD) method using a two furnace system. Sol-gel spin coated ZnO templates were used to enhance the growth of the nanoparticles. The thin films were deposited at 400 ~ 500 o C to study the effect of the deposition temperature on the properties of the thin films. The

  4. Chemical vapor deposition of functionalized isobenzofuran polymers

    E-print Network

    Olsson, Ylva Kristina

    2007-01-01

    This thesis develops a platform for deposition of polymer thin films that can be further tailored by chemical surface modification. First, we explore chemical vapor deposition of functionalized isobenzofuran films using ...

  5. 12 CFR 622.10 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...that time. The questions propounded and the answers thereto, together with all objections made (but not including argument or debate) shall be recorded by or under the direction of the person before whom the deposition is taken. The deposition...

  6. 7 CFR 47.16 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...deposition is to be conducted (telephone, audio-visual telecommunication, or by personal...manner of the deposition (telephone, audio-visual telecommunication, or personal...be conducted in the manner (telephone, audio-visual telecommunication, or...

  7. 19 CFR 210.28 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...investigation, any party may take the testimony of any person...examination. A party desiring to take the deposition of a person shall give notice in writing...agencies. A party desiring to take the deposition of an...

  8. 25 CFR 571.11 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Commissioner (or a person designated by a Commissioner under paragraph (a) of this section) proposing to take a deposition under this section shall give reasonable notice to the Commission and the parties, if any, of the taking of a deposition....

  9. 49 CFR 386.46 - Depositions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...recording. (b) Application. Any party desiring to take the deposition of a witness must indicate to the...to testify. (c) Notice. A party desiring to take a deposition must give notice to the witness and all other...

  10. 40 CFR 1610.4 - Deposition Transcripts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Deposition Transcripts. 1610.4 Section 1610.4 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD ADMINISTRATIVE INVESTIGATIONS § 1610.4 Deposition Transcripts. (a)...

  11. 40 CFR 1610.4 - Deposition Transcripts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Deposition Transcripts. 1610.4 Section 1610.4 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD ADMINISTRATIVE INVESTIGATIONS § 1610.4 Deposition Transcripts. (a)...

  12. 40 CFR 1610.4 - Deposition Transcripts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Deposition Transcripts. 1610.4 Section 1610.4 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD ADMINISTRATIVE INVESTIGATIONS § 1610.4 Deposition Transcripts. (a)...

  13. 40 CFR 1610.4 - Deposition Transcripts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Deposition Transcripts. 1610.4 Section 1610.4 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD ADMINISTRATIVE INVESTIGATIONS § 1610.4 Deposition Transcripts. (a)...

  14. 40 CFR 1610.4 - Deposition Transcripts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Deposition Transcripts. 1610.4 Section 1610.4 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD ADMINISTRATIVE INVESTIGATIONS § 1610.4 Deposition Transcripts. (a)...

  15. 37 CFR 2.208 - Deposit accounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...deposit account may be addressed to: Director of the United States Patent and Trademark Office, Attn: Deposit Accounts, 2051 Jamieson Avenue, Suite 300, Alexandria, Virginia 22314. [68 FR 48292, Aug. 13, 2003, as amended at 69 FR 43752, July...

  16. 37 CFR 2.208 - Deposit accounts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...deposit account may be addressed to: Director of the United States Patent and Trademark Office, Attn: Deposit Accounts, 2051 Jamieson Avenue, Suite 300, Alexandria, Virginia 22314. [68 FR 48292, Aug. 13, 2003, as amended at 69 FR 43752, July...

  17. Wind Tunnel Modeling of Small Particle Deposition

    Microsoft Academic Search

    D. I. McCready

    1986-01-01

    An inexpensive microsphere dispersion, deposition, and sampling system is described. This system was used to examine the transport and deposition of small particles (? 1 ?m diameter) across the aerodynamic boundary layer which developed over a prototype deposition surface (smooth, flat, acrylic plate). Unit density, polystyrene latex microspheres (0.8 and 1.1 ?m diameter) were deposited onto both oil-coated and dry,

  18. Accounts Payable EMPLOYEE DIRECT DEPOSIT AUTHORIZATION FORM

    E-print Network

    Tipple, Brett

    Payroll Setup Change Direct Deposit Information Cancel Direct Deposit HOSPITAL ACCOUNTS PAYABLE, 127 SOUTH bank information, or lack of Payee notification when a bank account is closed.1 Note: Changes to their depository accounts. Payee Information Important Notice Unlike payroll deposits, Accounts Payable cannot

  19. Mechanisms, models and methods of vapor deposition

    E-print Network

    Wadley, Haydn

    Mechanisms, models and methods of vapor deposition H.N.G. Wadley a, *, X. Zhou a , R.A. Johnson during its growth by vapor deposition is complex. Mediating the growth process by varying the ¯ux for high performance ®lms. A multiscale modeling method for ana- lyzing the growth of vapor deposited thin

  20. Cold spray deposition of thermoplastic powder

    Microsoft Academic Search

    Y. Xu; I. M. Hutchings

    2006-01-01

    The cold spray deposition of polyolefin powder has been investigated, at substantially lower velocities (up to ?135 m s?1) than those used in the cold gas dynamic spray (CGDS) process for metals. The particles were accelerated at room temperature in air through a cylindrical nozzle, and were deposited on to polyethylene and aluminium substrates. Fully-dense deposits were formed at temperatures substantially

  1. Metal spray deposition of cylindrical preforms

    Microsoft Academic Search

    José Tinoco; Björn Widell; Hasse Fredriksson

    2005-01-01

    A number of deposition experiments were carried out in a metal spray deposition facility for cylindrical preforms, at Sandvik Steel AB. Thick layers of modified Inconel 625 were sprayed over steel bars 170mm in diameter and 8m long. The rods were at room temperature during the deposition process. The effect of rotational velocity and fraction solidified in the spray was

  2. Deposition Processes with Hardcore Behaviour

    NASA Astrophysics Data System (ADS)

    Mountford, Thomas S.; Sudbury, Aidan

    2012-01-01

    Particles are deposited onto a surface with discrete sites. They are subject to an inhibition by which they cannot pass close by a particle already fixed on the surface. This implies that the surface builds up with vertical gaps between the particles. In this paper it is shown that there is a limiting rate at which the surface grows, and that this is related to the "roughness" of the surface.

  3. Measuring coal deposits by radar

    NASA Technical Reports Server (NTRS)

    Barr, T. A.

    1980-01-01

    Front-surface, local-oscillator radar directly compares frequency of signals reflected from front and back surfaces of coal deposits. Thickness is measured directly as frequency difference. Transmitter is frequency modulated, so thickness is computed directly from frequency difference. Because front and back reflections are detected in combination rather than separately, masking of comparatively weak back signal is less problem. Also system is not sensitive to extraneous reflections from targets between transmitting antenna and coal surface.

  4. Thermal Plasma Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Lu, Zhipeng

    Diamond has many unrivaled properties and has great application potentials in modern industry. Among various metastable chemical vapor deposition methods for producing diamond, thermal plasma chemical vapor deposition has shown advantages of offering high growth rates and high quality. However, systematic parametric studies are needed for optimization of the process. This study investigates the effects of substrate materials, substrate temperatures, substrate pre-treatment methods, precursor concentrations, and process pressures on the initial nucleation, growth rate, morphology, and quality of the diamond films under thermal plasma conditions. X-ray diffraction, optical microscopy, scanning electron microscopy, and Raman spectroscopy have been used for the diamond film characterization. Thermal plasmas have been also used to deposit homoepitaxial diamond films at high growth rates. High quality macro-sized diamond crystals have been grown on {100} and {110} oriented natural type IIa diamond seeds. Raman spectra reveal that the diamond deposit is of high quality. Laue X-ray diffraction patterns show that the diamond grown on the seed is single crystal and oriented epitaxially with the underlying seed crystal. The gas phase chemistry has been calculated using computer code SOLGASMIX to determine the equilibrium gaseous composition in thermal plasmas. Key species concentrations have been obtained under various pressure conditions. Although kinetic factors have not been taken into account, equilibrium conditions offer an estimation of the process justified by the "frozen chemistry" associated with the fast quenching in the boundary layer. Due to the strong emission of the highly luminous plasma plumes, it has been difficult to measure the in -situ substrate temperature distribution with conventional infrared optical pyrometers. A new technique has been developed to obtain the surface temperature distribution of the substrate by combining the experimental temperature measurements of an array of thermocouples imbedded in the substrate and analytical solutions of the two-dimensional heat conduction equation. This method enables an indirect determination of the substrate temperature distribution.

  5. Circum-Pacific diatomite deposits

    SciTech Connect

    North, F.K.

    1986-07-01

    Deformed diatomites of assured identification are all Oligocene or younger. They are not to be interpreted with oceanic diatom oozes as analogs, nor with California's Monterey Formation as prototype. All examples, apart from the unique Monterey, are deposits of relatively shallow waters at convergent plate or microplate boundaries: in arc-trench gaps or (less importantly) in immediate back-arc belts. Tethyan examples, along a collision boundary, are now slivers in the late stages of external flysch along the fronts of Alpine thrust belts. Circum-Pacific examples, at ocean-continent subduction boundaries, are preserved only on mountainous islands or peninsulas, the uplift (not folding) of which has protected the diatomites and their overlying evaporites from subduction. The control is tectonic and volcanic, not by water temperature or eustatism. Preserved deposits appear to be restricted to particular segments of the Pacific boundary delineated by Benioff zones having some significant minimum dip. The unique Monterey Formation owes its spectacular development and preservation to the conversion of an arc-trench boundary to a transform boundary, at a triple junction, before the diatomite was deposited. The Monterey's importance as an oil source sediment does not stem from its true diatomite component. Other Circum-Pacific diatomites are of negligible significance to the petroleum geologist, but are potentially minable for other uses in Japan, the Philippines, and Peru, and possibly in Chile.

  6. Ion beam deposited protective films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1981-01-01

    Sputter deposition of adherent thin films on complex geometric surfaces by ion beam sources is examined in order to evaluate three different types of protective coatings for die materials. In the first experiment, a 30 cm diameter argon ion source was used to sputter deposit adherent metallic films up to eight microns thick on H-13 steel, and a thermal fatigue test specimen sputter deposited with metallic coatings one micron thick was immersed in liquid aluminum and cooled by water for 15,000 cycles to simulate operational environments. Results show that these materials do protect the steel by reducing thermal fatigue and thereby increasing die lifetime. The second experiment generated diamond-like carbon films using a dual beam ion source system that directed an eight cm argon ion source beam at the substrates. These films are still in the process of being evaluated for crystallinity, hardness and infrared absorption. The third experiment coated a fiber glass beam shield incorporated in the eight-cm diameter mercury ion thruster with molybdenum to ensure proper electrical and thermal properties. The coating maintained its integrity even under acceleration tests.

  7. Dual Nitrate Isotopes in Dry Deposition: Utility for Partitioning Nox Source Contributions to Landscape Nitrogen Deposition

    EPA Science Inventory

    Dry deposition is a major component of total nitrogen deposition and thus an important source of bioavailable nitrogen to ecosystems. However, relative to wet deposition, less is known regarding the sources and spatial variability of dry deposition. This is in part due to diffi...

  8. From Leaf Synthesis to Senescence: n-Alkyl Lipid Abundance and D/H Composition Among Plant Species in a Temperate Deciduous Forest at Brown's Lake Bog, Ohio, USA

    NASA Astrophysics Data System (ADS)

    Freimuth, E. J.; Diefendorf, A. F.; Lowell, T. V.

    2014-12-01

    The hydrogen isotope composition (D/H, ?D) of terrestrial plant leaf waxes is a promising paleohydrology proxy because meteoric water (e.g., precipitation) is the primary hydrogen source for wax synthesis. However, secondary environmental and biological factors modify the net apparent fractionation between precipitation ?D and leaf wax ?D, limiting quantitative reconstruction of paleohydrology. These secondary factors include soil evaporation, leaf transpiration, biosynthetic fractionation, and the seasonal timing of lipid synthesis. Here, we investigate the influence of each of these factors on n-alkyl lipid ?D in five dominant deciduous angiosperm tree species as well as shrubs, ferns and grasses in the watershed surrounding Brown's Lake Bog, Ohio, USA. We quantified n-alkane and n-alkanoic acid concentrations and ?D in replicate individuals of each species at weekly to monthly intervals from March to October 2014 to assess inter- and intraspecific isotope variability throughout the growing season. We present soil, xylem and leaf water ?D from each individual, and precipitation and atmospheric water vapor ?D throughout the season to directly examine the relationship between source water and lipid isotope composition. These data allow us to assess the relative influence of soil evaporation and leaf transpiration among plant types, within species, and along a soil moisture gradient throughout the catchment. We use leaf water ?D to approximate biosynthetic fractionation for each individual and test whether this is a species-specific and seasonal constant, and to evaluate variation among plant types with identical growth conditions. Our high frequency sampling approach provides new insights into the seasonal timing of n-alkane and n-alkanoic acid synthesis and subsequent fluctuations in concentration and ?D in a temperate deciduous forest. These results will advance understanding of the magnitude and timing of secondary influences on the modern leaf wax ?D signal, thereby improving paleohydrology information extracted from leaf wax ?D.

  9. Results of Deposition Scoping Tests

    SciTech Connect

    Hu, M.Z.

    2003-03-04

    The processes of crystallization and solid deposit formation that led to the shutdown of the 2H evaporator operation at the Savannah River Site (SRS) and that could possibly cause similar problems in the future or in other evaporators need to be better understood. Through experimentation, thermodynamic modeling, and correlation of scaling to historical tank farm operations, progress has been made in developing guidelines as to the concentrations of silicon and aluminum that can be processed by evaporators while avoiding unacceptable levels of scale formation. However, because of limitations of the thermodynamic model and an insufficient amount of operational data at slightly supersaturated concentration levels, uncertainty still exists regarding acceptable feed concentrations. The objective of this effort is to provide information that can be used in defining acceptable levels of silicon and aluminum in evaporator feed solutions. Data collected previously showed that particle formation reactions can be rapid at evaporator temperatures for elevated silicon and aluminum concentrations. However, insufficient data exists to estimate the silicon and aluminum concentrations above which solids will form in the time frame of evaporator processing. The work described in this report was designed to determine the induction period for solutions of decreasing aluminum and silicon concentration such that the supersaturation level corresponding to a 4-h induction time for particle nucleation/growth in bulk solution can be estimated. In addition, experiments were conducted to explore the supersaturation levels that can result in deposition of solids on metal surfaces at varying aluminum-to-silicon concentration ratios. Laboratory studies of particle growth in solution were conducted at relatively low supersaturation levels. Dynamic-light-scattering (DLS) studies and deposition tests, similar to those performed in FY 2001, were conducted with solutions at relatively low supersaturation levels and at elevated temperatures to explore the formation of solids under conditions similar to those encountered in evaporator processing. The deposition of solids on stainless steel samples placed in the solutions during the experiments was simultaneously investigated. In addition, the deposition of solids on stainless steel surfaces was investigated in laboratory-scale batch evaporation experiments. Completion of this effort will aid the development of operating strategies to mitigate or avoid solid scale formation on surfaces in evaporator systems. The results are expected to benefit plant operations by helping to determine acceptable silicon and aluminum feed concentrations.

  10. Ocular lipid deposition and hyperlipoproteinaemia.

    PubMed

    Crispin, Sheila

    2002-03-01

    In all species there are potential ocular manifestations when circulating lipoproteins are raised and these may be transient or permanent Many factors, both systemic and local, influence lipid influx and accumulation (progression) and lipid mobilisation and efflux (regression). In both humans and animals some types of lipid deposition will regress if the local and systemic factors involved in pathogenesis can be modified. There are inescapable parallels with the same phenomena in other tissues.Three types of corneal lipid deposition have been linked with hyperlipoproteinaemia. In corneal arcus, lipid is deposited preferentially in the warmest part of the cornea initially and, in people, the lipid remains almost exclusively extracellular. In animals, corneal arcus is associated with initial extracellular lipid deposition followed by the appearance of intracellular lipid and vascularisation, so that established corneal arcus tends to become more typical of lipid keratopathy. In humans, hyperlipoproteinaemia may be an associated systemic factor and early onset corneal arcus is a recognised feature of certain primary hyperlipoproteinaemias and their secondary phenotypes. In dogs, corneal arcus is always associated with hyperlipoproteinaemia. Corneal vascularisation is a ubiquitous feature of lipid keratopathy in all species and both necrotic fibroblasts and foam cells are common in progressive lesions. The extent and position of lipid deposition and the evolution of lipid keratopathy can be related to local ocular disease and circulating lipids and lipoproteins. Many aspects of the pathogenesis of lipid keratopathy are similar to those of atherogenesis. Hyperlipoproteinaemia, especially hypercholesterolaemia is the commonest systemic abnormality. In crystalline stromal dystrophy (Schnyder's crystalline stromal dystrophy) of the cornea there is no inflammatory element and no vascularisation. The dystrophy is associated with accumulation of lipid within the corneal fibroblasts, but typical foam cells are absent, the crystalline opacity involves the coolest part of the cornea, correlates with local fibroblast death, and is always bilateral. Hyperlipoproteinaemia, may be present, but this is not universally so.The objective of this paper is to evaluate the factors that may influence ocular involvement in hyperlipoproteinaemia. A comparative approach, utilising information available from studies of both ocular and non-ocular tissues, aids elucidation of the complex pathogenesis. PMID:12062534

  11. The structural consequences of calcium crystal deposition.

    PubMed

    Durcan, Laura; Bolster, Ferdia; Kavanagh, Eoin C; McCarthy, Geraldine M

    2014-05-01

    Calcium pyrophosphate dihydrate and basic calcium phosphate (BCP) crystals are the most common calcium-containing crystals associated with rheumatic disease. Clinical manifestations of calcium crystal deposition include acute or chronic inflammatory and degenerative arthritides and certain forms of periarthritis. The intra-articular presence of BCP crystals correlates with the degree of radiographic degeneration. Calcium crystal deposition contributes directly to joint degeneration. Vascular calcification is caused by the deposition of calcium hydroxyapatite crystals in the arterial intima. These deposits may contribute to local inflammation and promote further calcification, thus aggravating the atherosclerotic process. Calcium crystal deposition results in substantial structural consequence in humans. PMID:24703349

  12. Particle deposition in granular media: Progress report

    SciTech Connect

    Tien, Chi

    1987-01-01

    This paper discusses topics on particle deposition in granular media. The six topics discussed are: experimental determination of initial collection efficiency in granular beds - an assessment of the effect of instrument sensitivity and the extent of particle bounce-off; deposition of polydispersed aerosols in granular media; in situ observation of aerosol deposition in a two-dimensional model filter; solid velocity in cross-flow granular moving bed; aerosol deposition in granular moving bed; and aerosol deposition in a magnetically stabilized fluidized bed. (LSP)

  13. Kinetics of silicon-germanium deposition by atmospheric-pressure chemical vapor deposition

    Microsoft Academic Search

    T. I. Kamins; D. J. Meyer

    1991-01-01

    The deposition of Si1?xGex alloy layers in an atmospheric-pressure, chemical vapor deposition reactor has been studied by separately examining the silicon and the germanium components of the deposition rate. The overall deposition rate increases approximately linearly with GeH4 partial pressure, but is relatively independent of SiH2Cl2 partial pressure. The silicon component of the deposition rate increases rapidly with increasing temperature

  14. High Rate Deposition of Microcrystalline Silicon Using Conventional Plasma-Enhanced Chemical Vapor Deposition

    Microsoft Academic Search

    Lihui Guo; Michio Kondo; Makoto Fukawa; Kimihiko Saitoh; Akihisa Matsuda

    1998-01-01

    The deposition of hydrogenated microcrystalline silicon (µc-Si:H) at a relatively high working pressure is performed using a conventional radio-frequency plasma-enhanced chemical vapor deposition method. Correlation of the deposition rate and crystallinity with deposition parameters, such as working pressure, flow rate, dilution ratio and input RF power, are studied. It was found that the deposition rate exhibits a maximum at around

  15. Factors influencing the deposition of inhaled particles.

    PubMed Central

    Yeh, H C; Phalen, R F; Raabe, O G

    1976-01-01

    Because the initial deposition pattern of inhaled particles of various toxic agents determines their future clearance and insult to tissue, respiratory tract deposition is important in assessing the potential toxicity of inhaled aerosols. Factors influencing the deposition of inhaled particles can be classified into three main areas: (1) the physics of aerosols, (2) the anatomy of the respiratory tract and (3) the airflow patterns in the lung airways. In the physics of aerosols, the forces acting on a particle and its physical and chemical properties, such as particle size or size distribution, density, shape, hygroscopic or hydrophobic character, and chemical reactions of the particle will affect the deposition. With respect to the anatomy of the respiratory tract, important parameters are the diameters, the lengths, and the branching angles of airway segments, which determine the deposition. Physiological factors include airflow and breathing patterns, which influence particle deposition. Various lung models used in predicting particle deposition are reviewed and discussed. The air-way structures of various animal species are compared, showing the unique structure of the human lung compared to the animal species under study. Regional deposition data in man and dog are reviewed. Recent deposition data for small rodents are presented, showing regional difference in deposition with the right apical lobe having the highest relative deposition. Images FIGURE 5. FIGURE 5. PMID:1001293

  16. 31 CFR 344.4 - What are Time Deposit securities?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false What are Time Deposit securities? 344.4 Section 344...SECURITIES-STATE AND LOCAL GOVERNMENT SERIES Time Deposit Securities § 344.4 What are Time Deposit securities? Time Deposit...

  17. 31 CFR 344.4 - What are Time Deposit securities?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false What are Time Deposit securities? 344.4 Section 344...SECURITIES-STATE AND LOCAL GOVERNMENT SERIES Time Deposit Securities § 344.4 What are Time Deposit securities? Time Deposit...

  18. 31 CFR 344.4 - What are Time Deposit securities?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false What are Time Deposit securities? 344.4 Section 344...SECURITIES-STATE AND LOCAL GOVERNMENT SERIES Time Deposit Securities § 344.4 What are Time Deposit securities? Time Deposit...

  19. 31 CFR 344.4 - What are Time Deposit securities?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false What are Time Deposit securities? 344.4 Section 344...SECURITIES-STATE AND LOCAL GOVERNMENT SERIES Time Deposit Securities § 344.4 What are Time Deposit securities? Time Deposit...

  20. 31 CFR 344.4 - What are Time Deposit securities?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false What are Time Deposit securities? 344.4 Section 344...SECURITIES-STATE AND LOCAL GOVERNMENT SERIES Time Deposit Securities § 344.4 What are Time Deposit securities? Time Deposit...

  1. Task 37 - Ash Deposition Course

    SciTech Connect

    David W. Brekke

    1998-12-31

    The goals of this Energy & Environmental Research Center project are to develop a short course for transferring technical information from the research community to the industrial community, to seek out the research needs of industry, and to continually upgrade course materials. The Coal Ash Behavior and Deposition short course developed in the project provides an overview of recent research that is increasing the understanding of mineral behavior in coal utilization. This research leads to the advancement of methods to predict ash behavior, which can economically resolve fouling problems for the utility industry.

  2. Ion beam deposited protective films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1981-01-01

    Single or dual ion beam sources were used to deposit thin films for different applications. Metal and metal oxide films were evaluated as protective coatings for the materials. Film adherence was measured and the most promising films were then tested under environments similar to operating conditions. It was shown that some materials do protect die material (H-13 steel) and do reduce thermal fatigue. Diamondlike films have many useful applications. A series of experiments were conducted to define and optimize new approaches to the manufacture of such films. A dual beam system using argon and methane gases was developed to generate these films.

  3. Deposition Step in MEMS Time Multiplexed Etch

    NASA Astrophysics Data System (ADS)

    Overzet, Lawrence; Saraf, Iqbal; Goeckner, Matthew

    2011-10-01

    The deposition step of the Bosch process is examined by first forming standard trenches using a Plasma-Therm DSE-II and then depositing on those for an extended time. The deposition profiles at the bottom and sidewalls of trenches provide useful insights into the physical processes driving deposition process. SEMs reveal a dense film at the top and bottom of the trench as expected; however, it has an isolated fiber structure (like blades of grass) along sidewalls. This sidewall ``film'' structure is independent of the reactor used to deposit, is not caused by the original sidewall scallops, and is not affected by an air break between trench formation and deposition. It is critically dependent upon the ion flux and energy. Our model shows that neutral flux alone cannot form such a deposit inside trenches. This indicates that the deposition step can be highly ion-enhanced and suggests that one reduce the ion flux during Bosch deposition steps to limit the deposition rate at the bottom of the trench/via and thereby increase the etch rate as well as prevent feature closing. Acknowledgement: This material is based upon work supported by the SRC under award number 2008-KJ-1831.

  4. Local deposition of high-purity Pt nanostructures by combining electron beam induced deposition and atomic layer deposition

    SciTech Connect

    Mackus, A. J. M.; Sanden, M. C. M. van de; Kessels, W. M. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Mulders, J. J. L. [FEI Electron Optics, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands)

    2010-06-15

    An approach for direct-write fabrication of high-purity platinum nanostructures has been developed by combining nanoscale lateral patterning by electron beam induced deposition (EBID) with area-selective deposition of high quality material by atomic layer deposition (ALD). Because virtually pure, polycrystalline Pt nanostructures are obtained, the method extends the application possibilities of EBID, whereas compared to other area-selective ALD approaches, a much higher resolution is attainable; potentially down to sub-10 nm lateral dimensions.

  5. 27 CFR 53.157 - Deposit requirement for deposits made for calendar quarters prior to July 1, 1995.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. 53...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. Note...deposit requirement for deposits made for calendar quarters beginning on or after July...

  6. 27 CFR 53.157 - Deposit requirement for deposits made for calendar quarters prior to July 1, 1995.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. 53...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. Note...deposit requirement for deposits made for calendar quarters beginning on or after July...

  7. 27 CFR 53.157 - Deposit requirement for deposits made for calendar quarters prior to July 1, 1995.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. 53...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. Note...deposit requirement for deposits made for calendar quarters beginning on or after July...

  8. 27 CFR 53.157 - Deposit requirement for deposits made for calendar quarters prior to July 1, 1995.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. 53...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. Note...deposit requirement for deposits made for calendar quarters beginning on or after July...

  9. 27 CFR 53.157 - Deposit requirement for deposits made for calendar quarters prior to July 1, 1995.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. 53...Deposit requirement for deposits made for calendar quarters prior to July 1, 1995. Note...deposit requirement for deposits made for calendar quarters beginning on or after July...

  10. Acid deposition: a national problem

    SciTech Connect

    Hendrey, G.R.

    1985-01-01

    The deposition of excessive quantities of sulfur and nitrogen from the atmosphere constitutes a problem encompassing all of the United States east of the Mississippi River. It also occurs in some areas of the western US. Calculations based on emission inventories and simplifying assumptions indicate electric utilities account for 66% of SO/sub 2/ emissions, 29% of NO/sub x/ emissions and about half of precipitation acidity. Acidification of clearwater lakes and streams is a widespread problem only in areas receiving rain with an average acidity less than or equal to 4.7. The dominant anion in such waters is SO/sub 4//sup 2 -/ and concentrations of aluminum derived from watershed acidification may exceed 200 ..mu..g 1/sup -1/. Changes in assemblages of aquatic biota become increasingly apparent as pH decreases below 6.0, and elimination of fish from some waters has been documented. The sensitivity of surface waters is controlled by and represents an integration of biogeochemical processes in their edaphic settings. Changes in surface water chemistry imply changes in the terrestrial environment. Direct evidence of changes in terrestrial environments is sparse. Nevertheless, observations of forest dieback in the US and abroad suggest that acid deposition may contribute to the problem. Very few credible studies are available which allow an evaluation of acid precipitation effects on crops.

  11. Phyllosilicate Deposits in Shalbatana Vallis

    NASA Technical Reports Server (NTRS)

    Wintzer, Anne E.; Allen, Carlton C.; Oehler, Dorothy Z.

    2011-01-01

    Shalbatana Vallis is an ancient river valley on Mars, the westernmost of the southern Chryse outflow channels. The geologic history of this area has significant implications for understanding Mars' hydrologic and climate history. The highland flood basalts are cut by large collapse depressions, multiple outflow channels, and chaotic terrain. An intravalley paleolake with a depth of over 400 m, in the 125 km diameter Orson Welles crater (Fig. 1) and the adjacent section of Shalbatana Vallis, was deduced from Mars Orbiter Laser Altimeter (MOLA) topography, evidence of shorelines and the occurrence of fan-delta deposits, including Gilbert-style deltas [1]. A number of CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) images with strong phyllosilicate signatures have been identified throughout the channel and nearby highlands (Fig. 1). A majority of the signatures are concentrated in areas exposed by impact cratering. Since such minerals can form by a variety of different geological processes, such as weathering, burial diagenesis, and hydrothermal alteration [2], the nature of the phyllosilicate deposits in the Shalbatana Vallis region may provide insights into the formation processes that took place and help to place constraints on the early aqueous activity in the region.

  12. Backward plume deposition as a novel technique for high deposition rate Fe nanoclusters synthesis

    NASA Astrophysics Data System (ADS)

    Lin, J. J.; Mahmood, S.; Tan, T. L.; Springham, S. V.; Lee, P.; Rawat, R. S.

    2007-03-01

    Fe nanoclusters with a much higher deposition rate and significantly less laser droplets were successfully synthesized by laser ablation of an Fe target along a circular strip which encircled the Si substrate mounted on the target itself. This method is coined as backward plume deposition (BPD). The mechanism of higher deposition rate for BPD was investigated by characterizing the ablated plume dynamics using time-resolved ICCD imaging. Detailed nanocluster morphology, deposition rates and magnetic properties were studied by SEM, surface profiler and VSM. This method opens up a new paradigm for industrial applications of pulsed laser deposition due to appreciably enhanced deposition rates with reduced laser droplets.

  13. Biogeosciences, 5, 925935, 2008 www.biogeosciences.net/5/925/2008/

    E-print Network

    Paris-Sud XI, Université de

    of greenhouse gas release under elevated N deposition rates in a restoring peat bog in NW Germany S. Glatzel1, I Europe, most bogs have a history of drainage and many of them are currently being restored. Success of restoration as well as greenhouse gas exchange of these bogs is influenced by environmental stress factors

  14. Chapter 1: Modelling Past Environmental Changes Using Lake Sediment Records

    E-print Network

    Short, Daniel

    metals. These include lake sediments (Haworth and Lund, 1984), peat bogs (Shotyk et al., 1998), ice sediments and peat bogs (Dörr et al., 1991; Evans et al., 1986; Farmer et al., 1997; Hamilton-Taylor, 1988 peat bogs are often referred to as collectors of solely atmospheric deposition and are not influenced

  15. Percolation in models of thin film depositions.

    PubMed

    Lebovka, N I; Manna, S S; Tarafdar, S; Teslenko, N

    2002-12-01

    We have studied the percolation behavior of deposits for different (2+1)-dimensional models of surface layer formation. The mixed model of deposition was used, where particles were deposited selectively according to the random (RD) and ballistic (BD) deposition rules. In the mixed one-component models with deposition of only conducting particles, the mean height of the percolation layer (measured in monolayers) grows continuously from 0.898 32 for the pure RD model to 2.605 for the pure BD model, but the percolation transition belongs to the same universality class, as in the two-dimensional (2D) random percolation problem. In two-component models with deposition of conducting and isolating particles, the percolation layer height approaches infinity as concentration of the isolating particles becomes higher than some critical value. The crossover transition from 2D to 3D percolation was observed with increase of the percolation layer height. PMID:12513374

  16. Percolation in models of thin film depositions

    NASA Astrophysics Data System (ADS)

    Lebovka, N. I.; Manna, S. S.; Tarafdar, S.; Teslenko, N.

    2002-12-01

    We have studied the percolation behavior of deposits for different (2+1)-dimensional models of surface layer formation. The mixed model of deposition was used, where particles were deposited selectively according to the random (RD) and ballistic (BD) deposition rules. In the mixed one-component models with deposition of only conducting particles, the mean height of the percolation layer (measured in monolayers) grows continuously from 0.898 32 for the pure RD model to 2.605 for the pure BD model, but the percolation transition belongs to the same universality class, as in the two-dimensional (2D) random percolation problem. In two-component models with deposition of conducting and isolating particles, the percolation layer height approaches infinity as concentration of the isolating particles becomes higher than some critical value. The crossover transition from 2D to 3D percolation was observed with increase of the percolation layer height.

  17. Ash deposition from low rank coals

    Microsoft Academic Search

    L. G. Austin; R. E. Conn

    1989-01-01

    A laboratory test furnace was utilized to investigate ash deposit initiation and build-up as related to pulverized coal (p.c.)-fired combustion systems. Vertical tube furnace ( drop-tube'') investigations were conducted to study both ash deposition on heat transfer surfaces in a utility boiler and ash deposit formation on gas turbine hot gas pathways. In these tests, the rate of coal ash

  18. Deposition Overview for Microsystems Learning Module

    NSDL National Science Digital Library

    This page from the Southwest Center for Microsystems Education features a learning module which presents a general overview of deposition processes use in the fabrication of microsystems. Deposition is the fabrication process in which thin films of materials are deposited on a wafer. A participant guide, instructor guide (both in PDF format) and a comprehensive powerpoint presentation are included. Visitors are encouraged to create an account and login in order to access the full set of resources.

  19. Cloud deposition to a spruce forest edge

    NASA Astrophysics Data System (ADS)

    Weathers, K. C.; Lovett, G. M.; Likens, G. E.

    Deposition from clouds to a spruce (Picea rubens Sarg.) forest edge on Hunter Mt. in the Catskill Mts of New York State was measured during 1987 and 1988 to determine whether the windward edge of forest floor receives greater deposition of water and ions via cloud water than the interior of a forest. Throughfall was used as a measure of deposition and was collected during cloud-only and mixed cloud-and-rain events along five windward-to-leeward transects in a 30 x 30 m forested area. Ambient cloud water was also collected in a passive collector and chemically analyzed. Trees at the edge of the forest received on average three times, and up to 15 times, greater deposition of ions than those in the interior of the forest. Lead content in samples from Hunter Mt. forest floor at the windward edge, relative to the interior, was enhanced as well. Using a regression of distance vs deposition, the deposition "half-distance", (i.e. the point at which the rate of cloud water deposition is 50% of the rate at the windward edge of the forest) was found to be 28 m. The cloud deposition data from this study are compared to other studies of Na particle deposition to low-elevation forest edges, which show similar deposition "half distances", ranging from ˜ 2 to 36 m into the forest. Most models of cloud deposition currently in use assume landscape homogeneity. Montane forest landscapes, however, are often highly heterogeneous, consisting of many "edges", and thus current models may seriously underestimate cloud deposition.

  20. Interlayers for diamond deposition on tool materials

    Microsoft Academic Search

    I. Endler; A. Leonhardt; H.-J. Scheibe; R. Born

    1996-01-01

    The direct deposition of diamond on such tool materials as hard metals and steels is difficult because graphitization occurs and adhesion is poor. The following hard coatings have been investigated concerning their suitability as interlayers for diamond growth: TiN, TiC, Si3N4, SiC, SiCxNy, (Ti, Si)Nx and pulsed arc deposited a-C (laser-arc). The diamond deposition was performed by hot-filament CVD. A