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1

Bogs  

NSDL National Science Digital Library

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!

Tv, Agonfly

2

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

USGS Publications Warehouse

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.

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

1952-01-01

3

Atmospheric nitrogen deposition promotes carbon loss from peat bogs.  

PubMed

Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with important, but still unknown, effects on their C balance. Here we present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from approximately 0.2 to 2 g.m(-2).yr(-1). We found that enhanced decomposition rates for material accumulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decomposition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains about whether decay-resistant Sphagnum will continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks. PMID:17151199

Bragazza, Luca; Freeman, Chris; Jones, Timothy; Rydin, Håkan; Limpens, Juul; Fenner, Nathalie; Ellis, Tim; Gerdol, Renato; Hájek, Michal; Hájek, Tomás; Iacumin, Paola; Kutnar, Lado; Tahvanainen, Teemu; Toberman, Hannah

2006-12-19

4

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

USGS Publications Warehouse

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.

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

1953-01-01

5

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

Microsoft Academic Search

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

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

6

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

Microsoft Academic Search

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

Vincent Gauci; Nancy Dise; David Fowler

2002-01-01

7

Current and historical record of indium deposition from the atmosphere to an ombrotrophic bog in northeastern United States  

NASA Astrophysics Data System (ADS)

The industrial production of indium is increasing dramatically due to new uses in the rapidly growing electronics, photovoltaic, and LED industries. Little is known, however, about the natural or industrial cycling of indium or its environmental behavior, despite the fact that industrial emissions to the atmosphere appear to have already exceeded natural emissions. The history of metal deposition from the atmosphere is often reflected in the vertical profiles of the metals in ombrotrophic bogs, which by definition do not receive surface or subsurface runoff. Analysis of a peat core obtained using a novel freeze corer at Thoreau's Bog in Concord, MA shows that the rate of indium deposition to the bog increased beginning in the early 1900s, peaked in the early 1970s, and then decreased dramatically to pre-1900 values by the present time. This profile is counter to the pattern of indium's industrial use, which has increased only in the past 30-40 years. The profile coincides well, however, with the estimated history of particulate emissions from smelting and from coal combustion in North America. Back-trajectory analysis suggests that smelting was the dominant source of atmospheric particles with high indium concentrations deposited to the bog. This study suggests that metal smelting and coal burning are currently indium's primary industrial environmental sources. While releases from the semiconductor and electronics industries are comparatively small at present, this scenario may change with the rapid growth of indium use in these industries.

White, S. O.; Keach, C.; Hemond, H.

2012-12-01

8

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)

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.

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

2008-06-01

9

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

PubMed

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

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

2012-08-01

10

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

11

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

SciTech Connect

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.

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

2009-03-15

12

Bog Plant Tissue Chemistry as Indicators of Regionally Elevated Atmospheric N and S Deposition in the Alberta Oil Sands Region  

NASA Astrophysics Data System (ADS)

Nitrogen oxide and sulfur oxide emission from ongoing development of oil sands in northern Alberta results in regionally elevated atmospheric deposition of N and S in an area where background deposition of both N and S is exceptionally low (less than 1 kg/ha/yr). Because bogs, which represent major landforms in the Alberta oil sands region, are believed to be N-limited and potentially sensitive to S inputs, we have been investigating the effects of elevated N deposition on C, N, and S cycling in bogs, as well as the potential of bogs to serve as monitors of N and S deposition. Toward this latter end, we have measured seasonal variation (5 sampling dates between June and October 2009) concentrations of N and S, as well as ?15N value, in leaf tissues (Picea mariana (ectomycorrhizal); Ledum groenlandicum, Oxycoccos microcarpon, Vaccinium vitis-idaea (ericoid mycorrhizal); Rubus chamaemorus, and Smilacina trifolia (nonmycorrhizal), Sphagnum (S. fuscum, S. capillifolium, S. magellanicum, S. angustifolium) moss capitula (top 1-cm of plant) and lichens (Cladina mitis and Evernia mesomorpha) at 5 bogs at distances ranging from 14 to 300 km from the heart of the oil sands mining area. Averaged across all sites and sampling dates, N concentrations in ectomycorrhizal, ericoid mycorrhizal, nonmycorrhizal, Sphagnum, and lichens was 8.6 + 0.2, 11.9 + 0.2, 26.3 + 0.6, 10.2 + 0.1, 7.2 + 0.2 mg/g, respectively; ?15N values were -10.3 + 0.1, -6.0 + 0.1, 1.7 + 0.2, -5.3 + 0.1, -4.7 + 0.1 mg/g, respectively, and S concentrations were 1.07 + 0.2, 1.31 + 0.2, 1.94 + 0.6, 1.46 + 0.2, 1.11 + 0.3 mg/g, respectively. Plant functional groups and individual species behaved differently with respect to both seasonal variation and site differences, often with significant interactions when analyzed using two-way analyses of variance. Some species exhibited seasonal variation in some aspects of plant tissue chemistry, while others did not; when a species did exhibit seasonal variation, the variation was rather consistent between sites. More importantly, however, canonical discriminant analysis (with potential variables of C, N, or S concentrations, C:N, C:S, or N:S ratios, and ?15N values) indicated that the five sites can be differentiated based on plant tissue chemistry, most clearly separating the site closest and the site farthest from the oil sands mining area. The first canonical axis explained between 66 and 91 percent of the overall variation, but the variables that were significantly correlated with the first canonical axis differed between species. We conclude that plant tissue chemistry exhibited a significant variation between plant functional groups, between species, between sites, and seasonally. Some of this variation appears to be related to distance from the heart of oil sands mining activity in northern Alberta, possibly reflecting regionally elevated atmospheric deposition of N and S. Bog plants, through analysis of tissue chemistry, have the potential to serve as biomonitors of the anticipated spread of elevated atmospheric N and S deposition as oil sands development continues to grow in northern Alberta.

Wieder, R.; Vile, M. A.; Scott, K. D.; Vitt, D. H.; Quinn, J.

2011-12-01

13

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

NASA Astrophysics Data System (ADS)

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 acid rain-impacted regions of the world. CH4 fluxes were measured at regular intervals using a static chamber/gas chromatographic flame ionization detector method. Total emissions of CH4 were reduced by between 21 and 42% relative to controls, although no significant differences were observed between treatments. Estimated total annual fluxes during the second year of the experiment were 16.6 g m-2 from the controls and (in order of increasing SO42- dose size) 10.7, 13.2, and 9.8 g m-2 from the three SO42- treatments, respectively. The relative extent of CH4 flux suppression varied with changes in both peat temperature and peat water table with the largest suppression during cool periods and episodes of falling water table. Our findings suggest that low doses of SO42- at deposition rates commonly experienced in areas impacted by acid rain, may significantly affect CH4 emissions from wetlands in affected areas. We propose that SO42- from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates. We further propose that this microbially mediated interaction may have a significant current and future effect on the contribution of northern peatlands to the global methane budget.

Gauci, Vincent; Dise, Nancy; Fowler, David

2002-01-01

14

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

Microsoft Academic Search

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

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

1990-01-01

15

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

Microsoft Academic Search

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

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

2008-01-01

16

Bog Plant Tissue Chemistry and N and S Accumulation in Peat are Influenced by Elevated N and S Deposition from Alberta Oil Sands Development  

NASA Astrophysics Data System (ADS)

Development of the oil sands resource in northern Alberta, Canada has led to elevated atmospheric N and S deposition, the N coming mainly from the exhaust of diesel fueled-trucks that haul the raw oil sands from the mine sites and the S coming mainly from refining. Against a background deposition of < 1 kg/ha/yr for both N and S, at sites within 15 km of the oil sands mining region we have measured current N and S deposition to be as high as 2 and 27 kg/ha/yr. With a goal of developing monitoring tools to assess the spatial extent of elevated N and S deposition in the region, we collected leaves, needles, or whole plants of 12 bog species (lichens: Cladina mitis and Evernia mesomorpha; Sphagnum mosses: S. capillifolium and S. fuscum; a tree: Picea mariana; ericaceous shrubs: Ledum groenlandicum, Oxycoccos microcarpus and Vaccinium vitis-idaea; deciduous forbs: Rubus chamaemorus and Smilacina trifolia) from 5 bogs ranging from 11 to over 250 km from the oil sands mining area. Samples were collected on 23 dates between May and October of 2009-2012 and were analyzed for C, N, and S concentrations. Six species (C. mitis, E. mesomorpha, S. fuscum, O. microcarpus, V. vitis-idaea, and R. chamaemorus) exhibited statistically significant increases in C:N ratio with increasing distance from the oil sands mining area. Five species (C. mitis, E. mesomorpha, S. fuscum, S. capillifolium, O. microcarpus) exhibited statistically significant increases in C:S ratio with increasing distance from the oil sands mining area. For three species (S. fuscum, E. mesomorpha, O. microcarpus), N concentrations gradually and significantly increased (C:N ratios decreased) over the four years of the study, with the rate of increase as high as 1 mg/g/yr at sites in close proximity to the oil sands mining area. In contrast, S concentrations in plant tissues generally did not increase over the four years, possibly because of increasing efforts to control S emissions from stacks. Using 210Pb-dated cores collected from 15 bogs ranging from ranging from 11 to over 250 km from the oil sands mining area, we demonstrated greater net N and S accumulation in peat over the most recent 25 years, as compared to the 25-50 time horizon. Moreover, net N and S accumulation decreased exponentially with distance from the oil sands mining region. These relationships indicate that higher N and S accumulation in peat is evident within a distance of about 20 km from the oil sands mining area. Our findings reveal that elevated N and S deposition from oil sands development affects plant tissue chemistry, with potential ramifications for both N and S cycling and potential vegetation change in bogs, and that atmospherically deposited N and S are retained in bog peat deposits.

Wieder, R.; Vile, M. A.; Quinn, J.; Albright, C. M.; Scott, K. D.; Vitt, D. H.

2013-12-01

17

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)

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.

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

2014-05-01

18

Mid and late Holocene dust deposition in eastern Canada - a preliminary multi-proxy record from the Baie bog (St. Lawrence Estuary, Quebec)  

NASA Astrophysics Data System (ADS)

Atmospheric mineral dust plays an important role in the Earth's climate through parameters such as atmospheric radiation, cloud properties and biogeochemical cycles. However, the high spatial and temporal variability of mineral dust and a lack of terrestrial archives in certain regions limit our understanding global dust-climate interactions. Ombrotrophic peatlands (bogs; atmospherically-fed only) are increasingly recognized as archives of atmospheric dust deposition. Their global distribution and high accumulation rates (i.e. high resolution) over the Holocene make them suitable substitute to marine and/or ice records. The Baie bog, located along the St. Lawrence Estuary (North Shore region, Quebec, Canada), was sampled to investigate dust deposition/palaeowinds in north eastern North America over the mid and late Holocene. The core was subsampled for elemental and isotopic geochemistry as well as particle size analyses, 210Pb and radiocarbon dating. Radiocarbon dating of the base of the peat sequence yielded an age of about 4300 yr cal BP. Initial results show periods of increased dust flux, calculated from REE concentrations, between 1000-1500 yr cal BP and 100-500 yr cal BP in the peat profile from 0.5 to 4 g m-2 yr-1. Higher dust fluxes usually occur in combination with greater particle size suggesting either stronger winds or a change of source. Periods of increased dust fluxes in the profile also correspond with changes in the macrofossil assemblages. A first attempt at source tracing through preliminary radiogenic isotopes analyses (Pb, Nd; ongoing) will also be discussed.

Pratte, Steve; Garneau, Michelle; De Vleeschouwer, François

2014-05-01

19

Historical records of atmospheric Pb deposition in four Scottish ombrotrophic peat bogs: An isotopic comparison with other records from western Europe and Greenland  

NASA Astrophysics Data System (ADS)

Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (14C, 210Pb) 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., 206Pb/207Pb), 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 postindustrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest (˜10 to 40 mg m-2 a-1) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m-2 a-1 by the early 2000s. The records from four peat bogs extend knowledge of the chronology of atmospheric Pb deposition trends across the northern hemisphere, there being general agreement with other environmental archive records from not only Scotland but also other countries in western Europe and Greenland. Nevertheless, during all periods investigated here, the isotopic composition of atmospheric Pb deposition across western Europe and Greenland exhibited variations in the relative importance of different sources of anthropogenic Pb, as well as some differences in timings and magnitudes of anthropogenic Pb contamination, arising from variations in local and regional sources of Pb deposition and possibly climatic regimes.

Cloy, J. M.; Farmer, J. G.; Graham, M. C.; MacKenzie, A. B.; Cook, G. T.

2008-06-01

20

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

USGS Publications Warehouse

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.

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

2004-01-01

21

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

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.

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

22

The Vanishing Bog.  

ERIC Educational Resources Information Center

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)

Hanif, Muhammad

1990-01-01

23

Investigating Bogs: An Interdisciplinary Adventure.  

ERIC Educational Resources Information Center

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)

Pankiewicz, Philip R.; Schneider, Lois

1995-01-01

24

Two thousand years of atmospheric rare earth element (REE) deposition as revealed by an ombrotrophic peat bog profile, Jura Mountains, Switzerland.  

PubMed

A peat core from a Swiss bog represents 2110 14C years of peat accumulation and provides a continuous record of atmospheric rare earth element (REE) deposition. This is the first study providing a time-series of all REE originating from the atmosphere. Concentrations of the 14 REE (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) were determined using inductively coupled plasma-mass spectrometry (ICP-MS) after dissolution of 200 mg aliquots of age-dated peat samples with 3 ml HNO3 and 0.1 ml HBF4 at 240 degrees C in a microwave autoclave. Strict quality control schemes were applied to ensure the accuracy of the applied analytical methodology. Previous analyses of selected REE by instrumental neutron activation analysis (INAA) in the same set of peat samples revealed that INAA frequently under- or overestimated REE concentrations in a systematic manner. Concentration profiles obtained for all REE were almost identical, except for Ce and Eu. Calculation of enrichment factors (EF) revealed a distinct depletion of heavy REE relative to light REE in peat samples since the beginning of the 19th century which marks the onset of the Industrial Revolution in Europe, suggesting a pronounced influence by anthropogenic activities. Enrichments of REE calculated using Sc as a reference element exceeded unity, relative to the Upper Continental Crust. Overall, EF in all peat samples ranged from 1.96 for Sm to 2.34 for Gd, with considerably lower EF for Ce (1.82) and Eu (1.44), respectively. A significant enrichment of all REE which may have been caused by military activities, was observed in the peat sample dating from World War II (1944); this exceptional sample, however, is not enriched in Ce. The concentration profiles of REE were similar but not identical to those of other lithogenic, conservative reference elements such as Sc, Y, Al, Zr and Ti. While it has been suggested that individual REE concentrations or the sum of REE can be used as a reference parameter to calculate crustal EF in environmental samples the data presented here indicates that anthropogenic emissions of REE cannot simply be ignored. PMID:12619765

Krachler, Michael; Mohl, Carola; Emons, Hendrik; Shotyk, William

2003-02-01

25

Method of purifying uraniferous aqueous solutions  

Microsoft Academic Search

A method is claimed for purifying uraniferous aqueous solutions containing impurities, particularly at least one of the elements zirconium and\\/or hafnium, and also containing at least one of the anions SOâ=, NOâ-, Cl- or F- acting as complexing agents for the uranium and impurities, by precipitation of said impurities by means of an alkaline agent. The method is characterized in

1985-01-01

26

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

Microsoft Academic Search

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

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

2001-01-01

27

Uraniferous opal, Virgin Valley, Nevada: conditions of formation and implications for uranium exploration  

USGS Publications Warehouse

Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5-20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal. ?? 1982.

Zielinski, R.A.

1982-01-01

28

Consequences of marginal drainage from a raised bog and understanding the hydrogeological dynamics as a basis for restoration  

NASA Astrophysics Data System (ADS)

Raised bogs in Ireland have long been exploited for local fuel utilisation. The drainage associated with such activities alters the hydrological regime of the bog as consolidation of the peat substrate results in significant water loss and subsidence of the bog. Undisturbed raised bog environments are typically characterised by distinct ecological systems, or ecotopes, which are controlled by the relationship between surface slopes, flow path lengths and drainage conditions. Shrinkage of the main peat profile, or catotelm, invariably alters these conditions, changes of which significantly damage ecotopes of conservational value. Clara Bog, Ireland, is one of western Europe's largest remaining raised bogs and on which much hydroecological research has been conducted since the early 1990's. Though a relatively intact raised bog, it has been extensively damaged in the past with the construction of a road through the centre of the bog known to have resulted in subsidence of 9-10m. However, the western tract of Clara Bog, Clara Bog West, has also subsided significantly since the early 1990's due to on-going peat cutting activities on the bogs margins. Current research now indicates that the bog is not an isolated hydrological entity, as generally perceived of bogs, but rather that Clara Bog West is intrinsically linked to the regional groundwater table, which appears to provide a significant ‘support' function to the bog. Hydrogeological monitoring and analysis has shown that water losses are not simply a result of lateral seepage of water through the peat profile at the bogs margins. Measurements of flow rates and electrical conductivity in drains bordering the bog indicate that little water is discharging laterally through the peat profile. However, piezometric head levels in mineral subsoil underlying the bog and close to the margins of the bog have decreased by 0.3 to 0.5m and 0.4 to 1.0m respectively since the early 1990s and it is believed that this is a result of vertical water losses in the peat profile not confined to the bog margins. Distinct zones of groundwater seepage in the marginal drains have been mapped based on hydrochemical and stable isotopic composition of the water and occur where drains have cut into permeable subsoil beneath the peat substrate and where the potentiometric surface of the regional groundwater table is below, or coincident with, the elevation at the base of the drain. Groundwater as a ‘supporting' ecological condition is usually confined to the perimeter of a raised bog, where peat and underlying clay thin towards the margin, allowing regional groundwater and peat water to converge and mix, thereby giving rise to characteristic nutrient rich ‘lagg' zone vegetation. However, in Clara Bog West it appears there is also a connection between the regional groundwater table and the high bog. Such a connection appears to be unique to Clara Bog West as a result of the prevailing geological conditions. A succession of Carboniferous Limestone to relatively permeable glacial till deposits to low permeability lacustrine clay sediment is the predominant underlying geology of the bog. However, there are areas where the glacial till protrudes through the lacustrine clay, which ordinarily isolates the high bog from underlying groundwater, thereby engendering a dependency on regional groundwater conditions. The hydrogeological data now suggest that drainage at the bog margin has created a hydraulic connection between these ‘subsoil subcrops' and the marginal drains, developed within the same subsoil, thereby lowering the regional groundwater table, steepening the hydraulic gradient and resulting in significant water loss from the main bog body. As such, understanding this hydrogeological connection is central to restoration activities that will aim to arrest subsidence and restore water levels that are indicative for ecotope development, on the high bog. Acknowledgements Clara Restoration Group: Jan Streekferk (Staatsbosbeheer), Jim Ryan (National Parks and Wildlife Service), Ray Flynn (Queens Univ

Regan, Shane; Johnston, Paul

2010-05-01

29

Redox Characteristics, Sequestration, and Concentration of Uranium in a Holocene Peat bog  

NASA Astrophysics Data System (ADS)

Understanding the fate of U during diagenetic processes is fundamental to predictions for how this element will be cycled through the environment and will give insight into ore development and the distribution of U in sedimentary rocks. U is known to be concentrated and immobilized in organic rich sediments. The classic model for uranium sequestration and accumulation in natural systems calls for reduction of aqueous U6+ followed by precipitation and deposition of less-soluble U4+ species, primarily uraninite. An ongoing debate concerns whether organic matter plays a direct role, by binding U, thus immobilizing it; or an indirect role by creating redox conditions thermodynamically favorable for the reduction of U and precipitation of uraninite. Reactive functional groups (e.g. carboxyl) of immature natural organic matter may form complexes with uranyl ion and may suppress the reduction of U even in the presence of microbial and thermodynamic conditions that are otherwise favorable for reduction. Thus, U may be available for reduction only upon degradation of the organic matter. There are few studies of the path to immobilization and concentration of U. Samples in this study were taken from a uraniferous Holocene peat bog. The high organic content and known age make this deposit ideal for examining the effects of organic matter on U mobility because it is formed almost exclusively by deposition and decay of natural organic matter. We have used synchrotron x-ray adsorption near edge spectroscopy (XANES) and micro-XAS to measure the in-situ oxidation state with a minimum of sample preparation and risk of contamination or reoxidation artifacts. The advantages of this method are maximized in this study by performing simultaneous XANES analysis of U and S in order to determine the redox state of the sediment as well as the U. Fe was also analyzed for additional host sediment redox characterization. Although the S and Fe analyses indicate that although the sediment Eh decreases with depth, the U remains oxidized throughout except for a narrow depth interval of partial reduction. These results suggest that a simple thermodynamic model of U reduction and precipitation does not explain the sequestration of U.

Bolanos, L.; Northrup, P.; Rasbury, T.; Zheng, Y.

2006-05-01

30

Pollen analysis of Patschke bog  

E-print Network

of the bog. The water gathers and flows westwards where it joins with Owens 23 Branch Creek. The soil here is a mucky black/brown clay loam. This area is marked by ~T ha latifolia L. (common t-t'1. ), ~Nh ~lt h p. ~hll (N 11. ) E. g Beal. (yellow cow... of the bog. The water gathers and flows westwards where it joins with Owens 23 Branch Creek. The soil here is a mucky black/brown clay loam. This area is marked by ~T ha latifolia L. (common t-t'1. ), ~Nh ~lt h p. ~hll (N 11. ) E. g Beal. (yellow cow...

Camper, Hope Armstrong

2012-06-07

31

Heavy metals in bog waters: An alternative way to assess atmospheric precipitation quality?  

NASA Astrophysics Data System (ADS)

Ombrotrophic bogs are used to reliably assess past and present levels of heavy metal depositions through chemical analyses of peat layers. Instead, surface waters collected in ombrotrophic bogs were never tested as an alternative way to assess atmospheric precipitation quality, although the solely source of water in bogs is by atmospheric precipitation. In the present paper the reliability of bog water to mirror atmospheric precipitation quality has been tested. To this aim, heavy metal concentrations in bog water were compared to both rainwater chemistry, and tissue chemistry of Hylocomium splendens, a moss frequently used as biomonitor. Bog water was periodically sampled in three different microhabitats, i.e., a hummock, a carpet, and a hollow at two bogs, located in the south-eastern Alps of Italy. Microhabitats were selected in order to encompass a gradient of water table depth from relatively dry to relatively wet conditions, respectively. Basing on surface peat and bog water chemistry as well as on hydrological measurements, selected microhabitats were shown to be ombrotrophic, i.e., their mineral input was solely by atmospheric precipitation. Heavy metal concentrations in bog water did not differ significantly among microhabitats, with the only exception of Fe which showed significantly higher concentrations in hummock water. Because of the lack of rainwater chemical information for the study area, mean heavy metal concentrations in rainwater were obtained from a set of European stations monitoring atmospheric precipitation. A significant relationship was found between heavy metals in rainwater and bog water, further supported by the positive relationship between emission amounts of Cd, Cr, Cu, Zn, and Pb in Italy and the corresponding values in bog water during the study period. Concentrations of heavy metals in bog water were then compared with corresponding concentrations in H. splendens collected in the nearby of the study bogs. Moss chemistry has been here used as a proxy of atmospheric precipitation chemistry, basing on the reliability of mosses to mirror local precipitation chemistry as widely demonstrated by biomonitoring surveys. Bog water and moss tissues showed the same pattern of variation of concentrations, although moss tissues were characterised by higher absolute concentrations of heavy metals.

Bragazza, Luca

2006-10-01

32

Lead atmospheric deposition rates and isotopic trends in Asian dust during the last 9.5 kyr recorded in an ombrotrophic peat bog on the eastern Qinghai-Tibetan Plateau  

NASA Astrophysics Data System (ADS)

A full understanding of the atmospheric Pb cycle in Asia during the Holocene is key to palaeoclimate studies of past atmospheric circulation patterns, as well as to assess the impact of increasing industrial activities in this region. However, long-term records of atmospheric Pb isotopic trends in Asia are still sparse. Consequently, we study changes in the concentrations, fluxes and isotopic signature of deposited Pb contained in a 14C-dated peat core from the eastern Qinghai-Tibetan Plateau, dating back to 9.5 kyr BP, and present the first peat record of the changing isotopic composition of atmospheric Pb in dust in Asia during this time. Lead concentrations and fluxes vary between 2.96-21.58 ?g g-1 and 0.06-3.52 mg m-2 y-1, respectively, with an average Pb baseline of 6.80 ± 4.18 ?g g-1. These values agree with other Pb studies of lake and peat archives in China but are one order of magnitude larger than early and mid-Holocene values measured in Europe. Lead isotopic variability throughout the core is small, varying between 206Pb/207Pb = 1.190-1.197, 206Pb/204Pb = 18.648-18.786, 207Pb/204Pb = 15.666-15.694 and 208Pb/204Pb = 38.890-39.090. The application of Bayesian trans-dimensional changepoint modelling to the Pb dataset enabled the identification of eight significant changes in the isotopic composition of the deposited Pb. Such changes mark different phases of atmospheric Pb deposition, and hence variations in atmospheric circulation patterns and environmental conditions. Temporal variations in the potential natural and/or anthropogenic Pb sources are assessed based on the 206Pb, 207Pb, 208Pb and 204Pb isotopic composition and the 1/[Pb] ratio of the peat samples. Our results suggest that Pb deposition throughout the Holocene was governed by local deposition and long-range input from natural dust sources in northwestern (Taklamakan desert and Qaidam basin) and northern China (Badain Jaran and Tengger deserts). Input from the northern sources seems to have been particularly important between 3.1-2.7 kyr BP and 1.7-0.9 kyr BP, suggesting a possible strengthening of the East Asian winter monsoon, in agreement with previous reconstructions in Asia. Based on the Pb/Sc and isotopic composition profiles we do not note any evidence for anthropogenic Pb derived from the thriving mining or smelting activities in northern and eastern China in the last few millennia, suggesting that atmospheric deposition to this region of the eastern Tibetan Plateau was dominated by natural Pb fluxes. These can serve as a true Asian "background" value against which anthropogenic impacts can be quantified. Our results confirm that the combination of radiogenic isotopes (Pb) and trace elements in peat bogs enables observational reconstructions of changes in past regional atmospheric circulation. Such records will enable more refined interpretations of marine and terrestrial palaeorecords in Asia and the Pacific and consequently provide further constraints for changes in ocean and atmospheric circulation and for the testing of palaeoclimate models of circulation patterns.

Ferrat, Marion; Weiss, Dominik J.; Dong, Shuofei; Large, David J.; Spiro, Baruch; Sun, Youbin; Gallagher, Kerry

2012-04-01

33

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

USGS Publications Warehouse

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.

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

2008-01-01

34

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

USGS Publications Warehouse

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 Minnesota to identify depth intervals in the peat profile where methanogenic metabolism occurs. Methanogenesis enriched the deuterium (2H) content of the deep peat pore waters by as much as +11% (Vienna Standard Mean Sea Water), which compares to a much greater enrichment factor of +70% in leachate from New York City's Fresh Kills landfill. The bog pore waters were isotopically dated by tritium (3H) to be about 35 years old at 1.5 m depth, whereas the landfill leachate was estimated as ~ 17 years old from Darcy flow calculations. According to an isotopic mass balance the observed deuterium enrichment indicates that about 1.2 g of CH4m-3 d-1 were produced within the deeper peat, compared to about 2.8 g CH4 m-3 d-1 in the landfill. The values for methane production in the bog peat are substantially higher than the flux rates measured at the surface of the bogs or at the landfill, indicating that deeper methane production may be much higher than was previously assumed.

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

2001-01-01

35

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

NASA Astrophysics Data System (ADS)

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 Minnesota to identify depth intervals in the peat profile where methanogenic metabolism occurs. Methanogenesis enriched the deuterium (2H) content of the deep peat pore waters by as much as +11‰ (Vienna Standard Mean Sea Water), which compares to a much greater enrichment factor of +70‰ in leachate from New York City's Fresh Kills landfill. The bog pore waters were isotopically dated by tritium (3H) to be about 35 years old at 1.5 m depth, whereas the landfill leachate was estimated as ˜17 years old from Darcy flow calculations. According to an isotopic mass balance the observed deuterium enrichment indicates that about 1.2 g of CH4 m-3 d-1 were produced within the deeper peat, compared to about 2.8 g CH4 m-3 d-1 in the landfill. The values for methane production in the bog peat are substantially higher than the flux rates measured at the surface of the bogs or at the landfill, indicating that deeper methane production may be much higher than was previously assumed.

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

2001-12-01

36

Uraniferous leucogranites south of Ida Dome, central Damara Belt, Namibia: Morphology, distribution and mineralisation  

NASA Astrophysics Data System (ADS)

Uranium deposits south of Ida Dome, Namibia, are hosted by networks of leucogranite dykes crosscutting lithostratigraphic units of the Damara Sequence. Examples are described that show a strong spatial relationship between uraniferous leucogranite and iron sulphide-rich schist containing pyrite, pyrrhotite, chalcopyrite and lesser bornite and molybdenite, situated between the Khan and Rossing or Karibib formations. Significant uranium deposition (above 400 ppm eU3O8) has occurred where this schist is thickest, e.g., in fold hinges, and where it has been infiltrated by large accumulations of leucogranite against a thick marble barrier. The marble played a mechanically important role by inhibiting magma migration, leading to ponding and increasing the degree of fluid-wallrock interaction. In this situation, the schist with high quantities of ferrous iron and reduced sulphides (pyrite, pyrrhotite and chalcopyrite) acted as an effective chemical trap for uranium transported in magmatic fluids. Recognition that the schist had a folded boudinage structure prior to leucogranite emplacement can help explain the partly stratabound, yet highly irregular and pod-like nature of the orebodies.

Corvino, Adrian F.; Pretorius, Leon E.

2013-04-01

37

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

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.

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

2003-01-01

38

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.

39

Bog Hot Springs, Nevada: the geothermal cycle  

Microsoft Academic Search

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)

1977-01-01

40

Vyrmethane Method. Biogas Extraction from Peat Bogs.  

National Technical Information Service (NTIS)

The Vyrmethane Method is based on the principle that the naturally gaseous water in the peat is pumped up and degassed in a vacuum tank. The gas is then led off and the water recirculated to the bog. On the basis of experience gained in conjunction with a...

L. Brolin

1988-01-01

41

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

NASA Astrophysics Data System (ADS)

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.

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

2008-01-01

42

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

Microsoft Academic Search

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

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

2007-01-01

43

Effects of nutrient addition on leaf chemistry, morphology, and photosynthetic capacity of three bog shrubs  

Microsoft Academic Search

Plants in nutrient-poor environments typically have low foliar nitrogen (N) concentrations, long-lived tissues with leaf traits\\u000a designed to use nutrients efficiently, and low rates of photosynthesis. We postulated that increasing N availability due to\\u000a atmospheric deposition would increase photosynthetic capacity, foliar N, and specific leaf area (SLA) of bog shrubs. We measured\\u000a photosynthesis, foliar chemistry and leaf morphology in three

Jill L. Bubier; Rose Smith; Sari Juutinen; Tim R. Moore; Rakesh Minocha; Stephanie Long; Subhash Minocha

44

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

45

137Cs in a raised bog in central Sweden  

Microsoft Academic Search

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

K. Rosén; M. Vinichuk; K. J. Johanson

2009-01-01

46

Origin of Lead in Eight Central European Peat Bogs Determined  

E-print Network

Research Origin of Lead in Eight Central European Peat Bogs Determined from Isotope Ratios. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering that environmental lead in Central Europe had been largely affected by human activity (smelting) even before

Wieder, R. Kelman

47

ANALYSES AND CORRELATION OF FOUR NEW HAMPSHIRE BOGS  

Microsoft Academic Search

The understanding of recent paleoecology by means of the pollen analyses of strata in post-glacial bogs has developed to the point where most ecologists, and even many laymen, are familiar with the usual methods involved. Although large numbers of bogs have been analyzed and discussed with regard to the immedi- ate locality to which they belong, there is still considerable

ROBERT W. KRAUSS; GEORGE N. KENT

48

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

Microsoft Academic Search

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

Marc J. Mazerolle

2003-01-01

49

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

NASA Astrophysics Data System (ADS)

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

Hall, G.

2010-12-01

50

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

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

Dmitri Mauquoy; Dan Yeloff

2008-01-01

51

Restoring afforested peat bogs: results of current research  

E-print Network

experiment, treatments that involved both felling trees and damming plough furrows were more successful than, but removing lop and top is not. Damming plough furrows can help to restore blanket bog but damming main drains

52

Peat Bog Archives: from human history, vegetation change and Holocene climate, to atmospheric dusts and trace elements of natural and anthropogenic origin  

NASA Astrophysics Data System (ADS)

For at least two centuries, peat has been recognized as an excellent archive of environmental change. William Rennie (1807), for example, interpreted stratigraphic changes in Scottish bogs not only in terms of natural changes in paleoclimate, but was also able to identify environmental changes induced by humans, namely deforestation and the hydrological impacts which result from such activities. The use of bogs as archives of climate change in the early 20th century was accelerated by studies of fossil plant remains such as those by Lewis in Scotland, and by systematic investigations of pollen grains pioneered by von Post in Sweden. In Denmark, Glob outlined the remarkably well-preserved remains of bog bodies and associated artefacts (of cloth, wood, ceramic and metal) in Danish bogs. In Britain, Godwin provided an introduction to the use of bogs as archives of human history, vegetation change, and Holocene climate, with a more recent survey provided by Charman. Recent decades have provided many mineralogical studies of peat and there is growing evidence that many silicate minerals, whether derived from the surrounding watershed or the atmosphere (soil-derived dusts and particles emitted from volcanoes), also are well preserved in anoxic peatland waters. Similarly, geochemical studies have shown that a long list of trace metals, of both natural and anthropogenic origin, also are remarkably well preserved in peat bogs. Thus, there is growing evidence that ombrotrophic (ie 'rain-fed') peat bogs are reliable archives of atmospheric deposition of a wide range of trace elements, including conservative, lithogenic metals such as Al, Sc, Ti, Y, Zr, Hf and the REE, but also the potentially toxic Class B, or 'heavy metals' such as Cu, Ag, Hg, Pb, Sb and Tl. When high quality measurements of these elements is combined with accurate radiometric age dating, it becomes possible to create high resolution reconstructions of atmospheric soil dust fluxes, ancient and modern metal pollution, and Holocene climate change.

Shotyk, William

2010-05-01

53

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...

54

Nitrogen dynamics in peat bogs: Comparison of sites with contrasting pollution levels (Central Europe)  

NASA Astrophysics Data System (ADS)

Nitrogen belongs to chemical elements whose biogeochemical cycles are most heavily disturbed by human activities, and large regions worlwide experience elevated depositions of reactive N (NO3-, NH4+). Peatlands contain as much as 15 % of the world's soil N. It it is unclear whether fertilizing by anthopogenic N will lead to higher storage of C in wetlands. Elevated N input may lead to both higher net primary productivity, but will also augment microbial decomposition. Here we discuss two aspects of N cycling in Sphagnum-dominated bogs in the Czech Republic, an area characterized by a steep north-south pollution gradient and high annual N deposition (60 kg ha-1). These two aspects are N inventory in 210Pb-dated peat cores, and post-depositional mobility of N in peat. We compared the N inventory in two Czech bogs, differing in pollution, with cumulative atmospheric N input. We hypothesized that the total amount of N in the peat cores would be smaller than the cumulative N input (leaching of excess N from the bog, denitrification). The two bogs were VJ (industrial north) and CB (rural south). The investigated period was 1885-2002. The total amount of N was 4020 kg ha-1 at VJ and 1530 kg ha-1 at CB. Peat in the north contained 2.6 times more N than in the south. Historical rates of N deposition in the Czech Republic are well known (numerous papers by Kopacek). To estimate cumulative N inputs into the bogs, we also used the monthly N depositions between 1994 and 2002, measured in two nearby catchments. The estimated cumulative atmospheric N input was 1350 kg ha-1 at VJ, and 530 kg ha-1 at CB. In both cases, the amount of N found in peat was 3 times higher than the estimated atmospheric N input. Such high storage of N in peat is surprising. Post-depositional mobility of N may help to explain the discrepancies between atmospheric N inputs and N storage in peat. We found two-fold evidence for post-depositional mobility of N. Maximum N concentrations at VJ were observed in layers dated at 1950, whereas pollution level increased up to 1980, and dropped thereafter. At the end of an 18-month reciprocal peat transplant experiment between VJ and CB, we found that N isotope ratios N converged to the host site. The magnitude of the isotope change was 3 per mil, the affected depth was 10 cm. Our results are consistent with the concept of Lamers et al. (2000) in that both ^15N and the found shift in N peaks downcore confirmed removal of N from surface moss under high N depositions. On the other hand, the excess of stored N relative to the cumulative N input remains unexplained, and merits further study.

Novak, Martin; Bohdalkova, Leona; Stepanova, Marketa; Vile, Melanie A.; Wieder, Kelman R.

2013-04-01

55

Effects of nutrient addition on leaf chemistry, morphology, and photosynthetic capacity of three bog shrubs.  

PubMed

Plants in nutrient-poor environments typically have low foliar nitrogen (N) concentrations, long-lived tissues with leaf traits designed to use nutrients efficiently, and low rates of photosynthesis. We postulated that increasing N availability due to atmospheric deposition would increase photosynthetic capacity, foliar N, and specific leaf area (SLA) of bog shrubs. We measured photosynthesis, foliar chemistry and leaf morphology in three ericaceous shrubs (Vaccinium myrtilloides, Ledum groenlandicum and Chamaedaphne calyculata) in a long-term fertilization experiment at Mer Bleue bog, Ontario, Canada, with a background deposition of 0.8 g N m(-2) a(-1). While biomass and chlorophyll concentrations increased in the highest nutrient treatment for C. calyculata, we found no change in the rates of light-saturated photosynthesis (A(max)), carboxylation (V(cmax)), or SLA with nutrient (N with and without PK) addition, with the exception of a weak positive correlation between foliar N and A(max) for C. calyculata, and higher V(cmax) in L. groenlandicum with low nutrient addition. We found negative correlations between photosynthetic N use efficiency (PNUE) and foliar N, accompanied by a species-specific increase in one or more amino acids, which may be a sign of excess N availability and/or a mechanism to reduce ammonium (NH(4)) toxicity. We also observed a decrease in foliar soluble Ca and Mg concentrations, essential minerals for plant growth, but no change in polyamines, indicators of physiological stress under conditions of high N accumulation. These results suggest that plants adapted to low-nutrient environments do not shift their resource allocation to photosynthetic processes, even after reaching N sufficiency, but instead store the excess N in organic compounds for future use. In the long term, bog species may not be able to take advantage of elevated nutrients, resulting in them being replaced by species that are better adapted to a higher nutrient environment. PMID:21544572

Bubier, Jill L; Smith, Rose; Juutinen, Sari; Moore, Tim R; Minocha, Rakesh; Long, Stephanie; Minocha, Subhash

2011-10-01

56

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

Federal Register 2010, 2011, 2012, 2013

...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...

2012-01-20

57

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

Federal Register 2010, 2011, 2012, 2013

...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...

2011-12-14

58

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

NASA Astrophysics Data System (ADS)

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.

Comas, Xavier; Slater, Lee; Reeve, Andrew

2005-12-01

59

Acidophilic Methanotrophic Communities from Sphagnum Peat Bogs  

PubMed Central

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

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

1998-01-01

60

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)

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.

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

2012-04-01

61

RESEARCH ARTICLE Demographic and genetic status of an isolated population of bog  

E-print Network

the range of the other bog turtle populations. Coalescent analysis of population growth rate, effectiveRESEARCH ARTICLE Demographic and genetic status of an isolated population of bog turtles (Glyptemys and genetic diversity of one isolated pop- ulation of the federally-threatened bog turtle (Glyptemys

Dorcas, Michael E.

62

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

E-print Network

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 patterns in the taphonomy of the insect fossil assemblages, through the development of the bog and across

Sheldon, Nathan D.

63

1999 Financial Disclosures of the Federal Reserve BOG  

NSDL National Science Digital Library

Released on September 4, 2000, the 1999 Financial Disclosures of the five members of the Fed's Board of Governors (BOG) offers fascinating insight into the "financial lives of America's most powerful economic policy makers." The data are displayed in an easy-to-read chart, offering information on the value of each governor's assets, assets of each governor and family, income from assets, and income from family assets. This site also offers bullet-pointed highlights of the findings, including the wealthiest governor and the financial investment choices of the BOG. The notes on each of the governors's statements are especially interesting.

64

Anomalous concentrations of zinc and copper in highmoor peat bog, southeast coast of Lake Baikal  

NASA Astrophysics Data System (ADS)

When examining the peat deposit discovered in Vydrinaya bog, South Baikal region, the authors encountered anomalous Zn and Cu concentrations for highmoors being up to 600-500 ppm on a dry matter basis in the Early Holocene beds (360-440 cm) formed 11 000-8500 years ago. It has been demonstrated that Zn and Cu are present inside the plant cells of peat moss in the form of authigenic sulfide minerals of micron size. Apart from Zn and Cu, native Ag particles (5-7 um) have been encountered in the peat of the Vydrinaya bog at a depth of 390-410 cm; these particles formed inside the organic matter of the plasma membrane of peat moss containing Ca, Al, S, and Cu. This study suggests probable patterns of the formation of zinc sulfides, copper sulfides, and native silver in peat moss. The results obtained indicate that biogenic mineral formation plays a significant role in this system, which is a very important argument in the discussion on the ore genesis, in which physicochemical processes are normally favored, while the role of living matter is quite frequently disregarded.

Bobrov, V. A.; Bogush, A. A.; Leonova, G. A.; Krasnobaev, V. A.; Anoshin, G. N.

2011-08-01

65

Spatial Patterns and Temporal Trajectories of the Bog Ground Layer  

E-print Network

along a chronosequence of post-fire bogs (1­105 years since fire) in north central Alberta, Canada. We soon post-fire (Sphagnum dominance in mature sites (20­80 ysf) with partial dominated by Sphagnum fuscum had the greatest species richness, although species evenness was low. Spatial

Benscoter, Brian W.

66

Methane emissions from fen, bog and swamp peatlands in Quebec  

Microsoft Academic Search

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

T. R. Moore; R. Knowles

1990-01-01

67

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 in soils across Scotland, contain fine ash produced by explosive eruptions in Iceland. They represent; Thordarson & Larsen 2007), but vary in size and explosivity. The primary threat to Scotland from the tephra

68

Geology and recognition criteria for uranium deposits of the quartz-pebble conglomerate type. Final report  

Microsoft Academic Search

This report is concerned with Precambrian uraniferous conglomerates. This class of deposit has been estimated to contain between approximately 16 and 35 percent of the global uranium reserve in two rather small areas, one in Canada, the other in South Africa. Similar conglomerates, which are often gold-bearing, are, however, rather widespread, being found in parts of most Precambrian shield areas.

A. Button; S. S. Adams

2012-01-01

69

SphagnumSphagnum Production and Decomposition in a Mountain Raised BogProduction and Decomposition in a Mountain Raised Bog TomTomss HHjekjek  

E-print Network

, decomposition and decomposability in six dominant Sphagnum species in a Central European mountain patterned mireSphagnumSphagnum Production and Decomposition in a Mountain Raised BogProduction and Decomposition in a Mountain Raised Bog TomTomásás HHáájekjek The Third International Symposium on the Biology of Sphagnum

Hájek, Tomá�

70

Belowground carbon turnover in a temperate ombrotrophic bog  

Microsoft Academic Search

To examine belowground carbon (C) turnover in peatlands, we measured fluxes of carbon dioxide (CO2) and methane (CH4) by chamber measurements, estimated respiration by in situ incubations of peat, and in situ production of dissolved carbon (CO2; CH4; and dissolved organic carbon, DOC) by pore water modeling at an ombrotrophic temperate bog. Ecosystem respiration (ER) averaged 205 mmol m-2 d-1

Christian Blodau; Nigel T. Roulet; Tobias Heitmann; Heather Stewart; Julia Beer; Peter Lafleur; Tim R. Moore

2007-01-01

71

Belowground carbon turnover in a temperate ombrotrophic bog  

Microsoft Academic Search

To examine belowground carbon (C) turnover in peatlands, we measured fluxes of carbon dioxide (CO2) and methane (CH4) by chamber measurements, estimated respiration by in situ incubations of peat, and in situ production of dissolved carbon (CO2; CH4; and dissolved organic carbon, DOC) by pore water modeling at an ombrotrophic temperate bog. Ecosystem respiration (ER) averaged 205 mmol m?2 d?1

Christian Blodau; Nigel T. Roulet; Tobias Heitmann; Heather Stewart; Julia Beer; Peter Lafleur; Tim R. Moore

2007-01-01

72

Properties and structure of raised bog peat humic acids  

NASA Astrophysics Data System (ADS)

Humic substances form most of the organic components of soil, peat and natural waters, and their structure and properties differ very much depending on their source. The aims of this study are to characterize humic acids (HAs) from raised bog peat, to evaluate the homogeneity of peat HAs within peat profiles, and to study peat humification impact on properties of HAs. A major impact on the structure of peat HAs have lignin-free raised bog biota (dominantly represented by bryophytes of different origin). On diagenesis scale, peat HAs have an intermediate position between the living organic matter and coal organic matter, and their structure is formed in a process in which more labile structures (carbohydrates, amino acids, etc.) are destroyed, while thermodynamically more stable aromatic and polyaromatic structures emerge as a result of abiotic synthesis. However, in comparison with soil, aquatic and other HAs, aromaticity of peat HAs is much lower. Comparatively, the raised bog peat HAs are at the beginning of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups change depending on the peat age and decomposition degree from where HAs have been isolated, and carboxylic acidity of peat HAs increases with peat depth and humification degree.

Klavins, Maris; Purmalis, Oskars

2013-10-01

73

Extracting phosphoric iron under laboratorial conditions smelting bog iron ores  

NASA Astrophysics Data System (ADS)

In recent years it has been indicated by archaeometric investigations that phosphoric-iron (P-iron, low carbon steel with 0,5-1,5wt% P), which is an unknown and unused kind of steel in the modern industry, was widely used in different parts of the world in medieval times. In this study we try to explore the role of phosphorus in the arhaeometallurgy of iron and answer some questions regarding the smelting bog iron ores with high P-content. XRF analyses were performed on bog iron ores collected in Somogy county. Smelting experiments were carried out on bog iron ores using a laboratory model built on the basis of previously conducted reconstructed smelting experiments in copies of excavated furnaces. The effect of technological parameters on P-content of the resulted iron bloom was studied. OM and SEM-EDS analyses were carried out on the extracted iron and slag samples. On the basis of the material analyses it can be stated that P-iron is usually extracted but the P-content is highly affected by technological parameters. Typical microstructures of P-iron and of slag could also be identified. It could also be established that arsenic usually solved in high content in iron as well.

Török, B.; Thiele, A.

2013-12-01

74

Decomposition in an ombrotrophic bog and a minerotrophic fen in Minnesota  

SciTech Connect

Using mass-loss and CO/sub 2/-evolution techniques, the authors evaluated the decomposition of peat in an ombrotrophic bog in northern Minnesota. They also compared decomposition potentials, using uniform material (cellulose), between the bog and a nearby minerotrophic fen. Mass loss decreased with increasing depth in the peat due to environmental and substrate limitations. Mass-loss from cellulose was greater in the fen than in the bog.

Farrish, K.W.; Grigal, D.F.

1988-05-01

75

Heat Transport in Peatlands: a bog and fen Comparison  

NASA Astrophysics Data System (ADS)

Peatlands are a major terrestrial source and sink of atmospheric methane, which is transported to the land surface by diffusion, advection and ebullition. Methane production is mostly related to seasonal variations in soil temperature and fluxes of labile carbon. We report the results of a study to explore the extent to which temperature variations in the anaerobic peat in a bog-fen complex (Red Lake Peatland, MN) is controlled by conduction or fluid convection. From November 1997 to August 1998, we measured hourly temperatures at 7 depths in a fen peat profile and from January 1998 to July 2000, at 12 depths at an adjacent raised bog. At both locations, we also measured hydraulic head at sub-daily time intervals. We modeled heat transport in the profiles with SUTRA, a finite-element numerical model code that couples heat transport with advection, and specified variable pressures and temperatures at the top and bottom of the models as boundary conditions. Measured daily average temperatures were used as the boundary conditions under steady-state flow system and transient heat transport conditions. Both models calibrated well to the field temperature data; the root mean squared error was 0.6 and 0.9 oC for the bog and fen models respectively. Calibrated bog and fen peat thermal conductivity was 0.5 and 1.0 J s-1 m-1 C-1 respectively. Modeled flux of groundwater into the fen peat base was ˜1 L day-1 m-2. The largest deviations between measured and modeled results at the bog was during spring months in the near surface peat. There, modeled temperatures increased rapidly from near 0 to 15 degrees, whereas measured temperatures slowly increased. The divergence between modeled and measured temperature is probably caused by ice melting in the upper peat, and slowing the transfer of heat further into the profile. In contrast, there is minimal discrepancy between modeling and measured temperature values at the fen, although the model deviates from measured values at mid-April, possibly because of changes in the amount of groundwater flux to the peat bottom.

McKenzie, J. M.; Siegel, D. I.; Glaser, P. H.

2004-12-01

76

Effect of mineral constituents in the bioleaching of uranium from uraniferous sedimentary rock samples, Southwestern Sinai, Egypt.  

PubMed

Bioleaching, like Biotechnology uses microorganisms to extract metals from their ore materials, whereas microbial activity has an appreciable effect on the dissolution of toxic metals and radionuclides. Bioleaching of uranium was carried out with isolated fungi from uraniferous sedimentary rocks from Southwestern Sinai, Egypt. Eight fungal species were isolated from different grades of uraniferous samples. The bio-dissolution experiments showed that Aspergillus niger and Aspergillus terreus exhibited the highest leaching efficiencies of uranium from the studied samples. Through monitoring the bio-dissolution process, the uranium grade and mineralogic constituents of the ore material proved to play an important role in the bioleaching process. The tested samples asserted that the optimum conditions of uranium leaching are: 7 days incubation time, 3% pulp density, 30 °C incubation temperature and pH 3. Both fungi produced the organic acids, namely; oxalic, acetic, citric, formic, malonic, galic and ascorbic in the culture filtrate, indicating an important role in the bioleaching processes. PMID:24682031

Amin, Maisa M; Elaassy, Ibrahim E; El-Feky, Mohamed G; Sallam, Abdel Sattar M; Talaat, Mona S; Kawady, Nilly A

2014-08-01

77

Ecology of Southeastern Shrub Bogs (POCOSINS) and Carolina Bays: A Community Profile.  

National Technical Information Service (NTIS)

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 Carol...

R. R. Sharitz, J. W. Gibbons

1982-01-01

78

Patterns of distribution of microfungi in decomposing bog and fen plants  

Microsoft Academic Search

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

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

2004-01-01

79

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

Microsoft Academic Search

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

D. H. Vitt; L. A. Halsey; S. C. Zoltai

1994-01-01

80

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

Microsoft Academic Search

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

Martin Novak; Petra Pacherova

2008-01-01

81

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

Microsoft Academic Search

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,

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

2007-01-01

82

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

SciTech Connect

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.

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

1994-02-01

83

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

E-print Network

Seasonal contribution of CO2 fluxes in the annual C budget of a northern bog Charlotte L. Roehm primary production exceeds decomposition. The contribution of non-growing-season fluxes to the annual C of carbon exchange with seasons in a bog located in the cool temperate climate region. The growing season CO

Roulet, Nigel T.

84

Content and Binding Forms of Heavy Metals, Aluminium and Phosphorus in Bog Iron Ores from Poland  

Microsoft Academic Search

Bog iron ores are widespread in Polish wetland soils used as meadows or pastures. Th ey are suspected to contain high concentrations of heavy metals, which are precipitated together with Fe along a redox gradient. Th erefore, soils with bog iron ore might be important sources for a heavy metal transfer from meadow plants into the food chain. However, this

Danuta Kaczorek; Gerhard W. Brümmer; Michael Sommer

2009-01-01

85

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

Microsoft Academic Search

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

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

2012-01-01

86

[Testate amoebae inhabiting middle taiga bogs in Western Siberia].  

PubMed

The population of testate amoebae from the most typical middle taiga bogs of Western Siberia have been studied. More than one hundred (103) species and intraspecific taxons of testate amoebae have been revealed in recent surface samples. The relation between ecological characteristics of habitats and the composition of a Protozoa population has been demonstrated. The ecological preferences of species concerning the index of wetness, ash level, and acidity have been revealed. Using the correspondence analysis, the ecological optimums and the tolerance of species and intraspecific taxons of testate amoebae have been established. PMID:20799643

Kur'ina, I V; Pre?s, Iu I; Bobrov, A A

2010-01-01

87

Fate of silicate minerals in a peat bog  

SciTech Connect

An investigation of silicate weathering in a Minnesota mire indicates that quartz and aluminosilicates rapidly dissolve in anoxic, organic-rich, neutral-pH environments. Vertical profiles of pH, disolved silicon, and major cations were obtained at a raised bog and a spring fen and compared. Profiles of readily extractable silicon, diatom abundance, ash mineralogy, and silicate surface texture were determined from peat cores collected at each site. In the bog, normally a recharge mound, dissolved silicon increases with depth as pH increases, exceeding the background silicon concentration by a factor of two. Silicate grain surfaces, including quartz, are chemically etched at this location, despite being in contact with pore water at neutral pH with dissolved silicon well above the equilibrium solubility of quartz. The increasing silica concentrations at circum-neutral pH are consistent with a system where silicate solubility is influenced by silica-organic-acid complexes. Silica-organic-acid complexes therefore may be the cause of the almost complete absence of diatoms in decomposed peat and contribute to the formation of silica-depleted underclays commonly found beneath coal.

Bennett, P.C. (Univ. of Texas, Austin (USA)); Siegel, D.I.; Hill, B.M. (Syracuse Univ., NY (USA)); Glaser, P.H. (Univ. of Minnesota, Minneapolis (USA))

1991-04-01

88

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

PubMed

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

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

2014-01-01

89

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

PubMed Central

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

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

2014-01-01

90

Fault rocks and differential reactivity of minerals in the Kanawa Violaine uraniferous vein, NE Nigeria  

NASA Astrophysics Data System (ADS)

The Kanawa Violaine uraniferous vein occurs in a narrow granitic shear zone. Mylonitic fault rocks at the centre of the vein grade outwards into cataclasites and fault breccias. The mineralization is associated with pervasive silicification and phyllosilicate alteration of the feldspar phases. The uranium mineralization occurs as uraninite-rich veinlets within brittle structures. Feldspars were the phenocryst phases most affected by alteration during the brittle-ductile deformation of the host rock. Plagioclase was extensively altered to micas, chlorite ± epidote, ±albite. Alkali-feldspar deformed mainly by transgranular fracturing as a result of shearing to yield clasts with lensoid shape. Quartz shows little evidence of brittle deformation but extensive in situ recrystallization. A mylonitic foliation is defined by monomineralic lenses. Microcracks in the feldspar are oblique to this foliation. The greenschist-facies secondary mineral assemblage, pervasive silicification, deformation mode of alkali-feldspar and the presence of quartz subgrains point to deformation of granites in the epizone by simple shearing within a hydrothermal-fluid-infiltrated medium. Alteration temperatures did not exceed 250 °C. The hydrothermal fluid remobilized and subsequently concentrated the uranium. This fluid was enriched in Si 4+, Na + and K +, possibly derived from plagioclase alteration. This lead to association of the ore with phyllosilicate and silicification alterations.

Suh, C. E.; Dada, S. S.

1997-08-01

91

Ecology and hydrology of pristine and cutover lowland raised bogs: relationships and implications for restoration  

NASA Astrophysics Data System (ADS)

This paper will examine relationships in vegetation communities and hydrological conditions on areas of lowland raised bog in north west England, comparing damaged and relatively intact sites on two adjacent bogs in Cumbria. Walton Moss is a relatively pristine site whilst and Bolton Fell Moss has a small nature reserve area with remnant vegetation which is surrounded by commercial peat cutting. The intended outcome is to provide a mechanism to inform management decisions, with a view to assisting in the long-term protection and rehabilitation of lowland raised bogs.

Labadz, Jillian; Hart, Roger; Robbins, Jane; Butcher, David; Topliss, David

2013-04-01

92

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

NASA Astrophysics Data System (ADS)

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?

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

2007-12-01

93

Biomonitoring of 210Po and 210Pb using lichens and mosses around a uraniferous coal-fired power plant in western Turkey  

NASA Astrophysics Data System (ADS)

In Gökova region where Yata?an is located there are three major uraniferous coal-fired power plants (CPPs) and they cause some pollution in the surroundings. Studies were realized over a wide area around the coal-fired power station located at Yata?an to evaluate the possible increase of natural radioactivity level due to the operation of the plant. The lichens Rhizoplaca melanophthalma, Cladonia convoluta, Cladonia pyxidata and the mosses Grimmia pulvinata, Hypnum cupressiforme were investigated for potential use as bioindicators for 210Po and 210Pb deposition. The maximum 210Po and 210Pb activities were observed around the hill close to ash stacks. The capture efficiency was the highest in one of the moss species, G. pulvinata with the activity concentration ranges of 600±19-1228±36 and 446±15-650±21 Bq kg -1 for 210Po and 210Pb, respectively. Soil samples were also collected and analysed in order to investigate any possible contamination in soil profiles due to CPPs and to determine unsupported 210Pb flux. The 210Pb and 226Ra concentrations in uncultivated soil profiles varied between 58±2 and 258±6 Bq kg -1, 50±5 and 58±5 Bq kg -1, respectively. The unsupported 210Pb inventory in the core was calculated to be 3312 Bq m -2. The corresponding annual 210Pb flux of 103 Bq m -2yr -1 is high with compare to estimates of the atmospheric flux given in literature for the same region.

U?ur, A.; Özden, B.; Saç, M. M.; Yener, G.

94

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

Microsoft Academic Search

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).

Michael E. Smith

1986-01-01

95

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

Microsoft Academic Search

(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

R. S. Clymo

1980-01-01

96

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. The relationship be- tween algal flora and the environmental characteristics of the pools was studied. The p

97

Community assembly of Diptera following restoration of mined boreal bogs: taxonomic and functional diversity  

Microsoft Academic Search

Peat mining causes major degradation to bogs and natural regeneration of these sites is slow and often incomplete. Thus, restoration\\u000a is an important tool for re-establishing natural ecosystem properties (although perhaps not the original species pool) in\\u000a mined bogs. Because faunal recovery cannot be taken for granted following plant restoration, we assessed community assembly\\u000a of higher flies (Diptera: Brachycera) in

Amélie Grégoire Taillefer; TailleferTerry A. Wheeler

98

Methanogenesis in McLean Bog, an Acidic Peat Bog in Upstate New York: Stimulation by H2\\/CO2 in the Presence of Rifampicin, or by Low Concentrations of Acetate  

Microsoft Academic Search

Acidic peat bog soils produce CH4 and although molecular biological studies have demonstrated the presence of diverse methano-genic populations in them, few studies have sustained methanogenesis by adding the CH4 precursors H2\\/CO2 or acetate, and few indigenous methanogens have been cultured. McLean Bog is a small (ca. 70 m across), acidic (pH 3.4–4.3) Sphagnum-dominated bog in upstate New York. Although

S. L. Bräuer; J. B. Yavitt; S. H. Zinder

2004-01-01

99

Baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota  

SciTech Connect

This baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota, evaluates the potential impacts to public health or the environment from contaminated ground water at this site. This contamination is a result of the uraniferous lignite ashing process, when coal containing uranium was burned to produce uranium. Potential risk is quantified only for constituents introduced by the processing activities and not for the constituents naturally occurring in background ground water in the site vicinity. Background ground water, separate from any site-related contamination, imposes a percentage of the overall risk from ground water ingestion in the Bowman site vicinity. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project is developing plans to address soil and ground water contamination at the site. The UMTRA Surface Project involves the determination of the extent of soil contamination and design of an engineered disposal cell for long-term storage of contaminated materials. The UMTRA Ground Water Project evaluates ground water contamination. Based on results from future site monitoring activities as defined in the site observational work plan and results from this risk assessment, the DOE will propose an approach for managing contaminated ground water at the Bowman site.

Not Available

1994-11-01

100

The growth of permafrost-free bogs at the southern margin of permafrost, 1947-2010  

NASA Astrophysics Data System (ADS)

In the high-Boreal region of NW Canada, permafrost occurs predominantly in the form of tree-covered peat plateaus within a permafrost-free and treeless terrain dominated by flat bogs. This region is experiencing unprecedented rates of thaw. Over the last several decades, such thaw has significantly expanded the permafrost-free, treeless terrain at the expense of the plateaus. This rapid change in land-cover has raised concerns over its impact on northern water resources, since remotely sensed data and ground observations indicate that the two major land-covers in this region have very different hydrological functions. Peat plateaus have a limited capacity to store water, a relatively large snowmelt water supply and hydraulic gradients that direct excess water into adjacent permafrost-free wetlands. As such, the plateaus function primarily as runoff generators. Plateaus also obstruct and redirect water movement in adjacent wetlands since the open water surfaces of the latter occupy an elevation below the permafrost table. By contrast, bogs are primarily water storage features since they are surrounded by raised permafrost and therefore less able to exchange surface and near-surface flows with the basin drainage network. Accurate estimate of the permafrost and permafrost-free areas is needed for accurate predictions of basin runoff and storage. This study examines the perimeter-area characteristics of bogs and permafrost plateaus, using fractal geometry as a basis for quantifying these properties. Image analyses are applied to aerial photographs and satellite imagery of Scotty Creek, NWT over the period 1947-2010. Preliminary analyses suggest that the expanding bogs and shrinking permafrost plateaus behave as fractals, meaning that their perimeter-area characteristics can be described by simple power equations. The area-frequency characteristics of bogs and plateaus have a hyperbolic distribution with relatively few large bogs and plateaus and numerous small ones. The bogs and plateaus have different fractal dimensions, since bogs evolve from small, simple (i.e. circular) shapes to large, complex shapes, while thaw transforms plateaus from large and complex shapes to small, simple ones. It is concluded that the size distributions of plateaus and bogs are not random but predictable. The variation in plateau edge length per unit basin area over the 1947-2010 period is demonstrated. A maximum value of the ratio was reached when permafrost covered 45-65% of the basin. Permafrost thaw driven by energy advection from adjacent bogs would therefore be greatest when the coverage of plateaus is in this range.

Quinton, W. L.; Sonnentag, O.; Connon, R.; Chasmer, L.

2013-12-01

101

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

NASA Astrophysics Data System (ADS)

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.

El Bilali, H.; Patterson, R.

2009-12-01

102

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

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

103

Transient modelling of water-table variation in a floodplain wetland, Narborough Bog, Leicestershire  

NASA Astrophysics Data System (ADS)

This paper describes the application of a transient three-dimensional groundwater model to simulate water flux through a floodplain wetland, Narborough Bog, in Central England. The results of a programme of water-table monitoring are summarised to indicate the extent of water-table fluctuation, and experiments to determine hydraulic flow parameters are detailed. Hydraulic conductivities of deposits are highly variable; observations were in the range 1.16 × 10 -3-4.63 × 10 -2 cm s -1 for herbaceous peat, 1.16 10 -4 cm s -1 for wood peat, and 9.14 × 10 -6-3.36 × 10 -8 cm s -1 for silty clay. A three-layer groundwater model of the wetland is developed using MODFLOW from these initial values, and with stratigraphic data obtained by hand augering. The model is calibrated using data for two periods of recharge from precipitation by adjusting specific yield and vertical hydraulic conductivity within prescribed limits. The accuracy of the model is then assessed by comparing daily model predictions of water-table response to potential evapotranspiration at specific monitoring points. Model, results demonstrate the importance of variation in hydraulic characteristics with depth in wetlands, thus emphasizing the dependence of water-table response upon water-table position, and preceding moisture conditions. The resulting water-table configuration reflects the balance between horizontal and lateral water flow through the wetland, and its relationship to river stage. The success of the stratigraphic representation is considered and its general applicability evaluated. Finally, the use of the calibrated model for local hydrological management is considered, and the effects on the wetland water budget of varying river stage by specified amounts are examined.

Bradley, C.

1996-11-01

104

Simulation of the annual water table dynamics of a floodplain wetland, Narborough Bog, UK  

NASA Astrophysics Data System (ADS)

This paper describes the simulation of a succession of annual hydro-periods describing water table variations in a British floodplain wetland, Narborough Bog. This is achieved through the application of a model, developed using MODFLOW, which requires inputs of weekly precipitation, evapotranspiration and river stage. The model reproduces the observed temporal variation in the wetland water tables illustrating the range in water table conditions experienced by the wetland, their relationship to hydrometeorological conditions, and the seasonal and annual variability in the wetland water budget. The model also estimates defuse water fluxes such as seepage flows to and from the adjacent river. The model simulations demonstrate the importance of successful representation of the stratigraphy of alluvial and organic deposits within the wetland. Model performance is evaluated for 2 years: 1991 and 1992 during a period of field instrumentation. The model is then used to reproduce the wetland hydroperiod for further 6 years: 1979, 1980, 1982, 1983, 1987 and 1988 when local data for precipitation, evapotranspiration and river stage are available. The results indicate how the wetland responds to a combination of hydrological events and emphasise the importance of precipitation—both weekly totals and its annual distribution. The model simulations reveal the importance of the water storage function of the wetland and indicate the varying relationship of the wetland to the lowland river: at low flows the river represents a base level to which the wetland water table grades. Conversely, for small periods of time wetland water tables are elevated by the effects of a marginal silt-clay levee adjacent to the riverbank. Conditions of influent seepage from river to wetland were experienced only on isolated occasions. Such results demonstrate the benefits of floodplain wetlands in moderating extremes of river flow and demonstrating the need for rivers and floodplain wetlands to remain closely integrated.

Bradley, C.

2002-04-01

105

The Sphagnum microbiome supports bog ecosystem functioning under extreme conditions.  

PubMed

Sphagnum-dominated bogs represent a unique yet widely distributed type of terrestrial ecosystem and strongly contribute to global biosphere functioning. Sphagnum is colonized by highly diverse microbial communities, but less is known about their function. We identified a high functional diversity within the Sphagnum microbiome applying an Illumina-based metagenomic approach followed by de novo assembly and MG-RAST annotation. An interenvironmental comparison revealed that the Sphagnum microbiome harbours specific genetic features that distinguish it significantly from microbiomes of higher plants and peat soils. The differential traits especially support ecosystem functioning by a symbiotic lifestyle under poikilohydric and ombrotrophic conditions. To realise a plasticity-stability balance, we found abundant subsystems responsible to cope with oxidative and drought stresses, to exchange (mobile) genetic elements, and genes that encode for resistance to detrimental environmental factors, repair and self-controlling mechanisms. Multiple microbe-microbe and plant-microbe interactions were also found to play a crucial role as indicated by diverse genes necessary for biofilm formation, interaction via quorum sensing and nutrient exchange. A high proportion of genes involved in nitrogen cycle and recycling of organic material supported the role of bacteria for nutrient supply. 16S rDNA analysis indicated a higher structural diversity than that which had been previously detected using PCR-dependent techniques. Altogether, the diverse Sphagnum microbiome has the ability to support the life of the host plant and the entire ecosystem under changing environmental conditions. Beyond this, the moss microbiome presents a promising bio-resource for environmental biotechnology - with respect to novel enzymes or stress-protecting bacteria. PMID:25113243

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

2014-09-01

106

A multi-proxy palaeoenvironmental investigation of the findspot of an Iron Age bog body from Oldcroghan, Co. Offaly, Ireland  

Microsoft Academic Search

In 2003, the remains of an Early Iron Age bog body, known as ‘Oldcroghan Man’, were recovered during the cutting of a drainage ditch in a bog in the Irish Midlands. Only some fingernails and a withe fragment remained undisturbed in situ in the drain face, providing the sole evidence for the original position of the body. A detailed reconstruction

Gill Plunkett; Nicki J. Whitehouse; Valerie A. Hall; Dan J. Charman; Maarten Blaauw; Eamonn Kelly; Isabella Mulhall

2009-01-01

107

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

USGS Publications Warehouse

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.

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

1987-01-01

108

Biomonitoring of 210Po and 210Pb using lichens and mosses around a uraniferous coal-fired power plant in western Turkey  

Microsoft Academic Search

In Gökova region where Yata?an is located there are three major uraniferous coal-fired power plants (CPPs) and they cause some pollution in the surroundings. Studies were realized over a wide area around the coal-fired power station located at Yata?an to evaluate the possible increase of natural radioactivity level due to the operation of the plant. The lichens Rhizoplaca melanophthalma, Cladonia

A. U?ur; B. Özden; M. M. Saç; G. Yener

2003-01-01

109

Variation in methane production pathways associated with permafrost decomposition in collapse scar bogs of Alberta, Canada  

Microsoft Academic Search

Stable isotope analysis was used to determine the distribution of methanogenic pathways at permafrost collapse scar bogs to test the hypothesis that microbial respiration and methane production are stimulated by the input of organic matter associated with permafrost degradation and collapse. An alternative hypothesis is that recently assimilated carbon produced by the fen-like vegetation (Carex, Eriophorum) growing in open water

James L. Prater; Jeffrey P. Chanton; Gary J. Whiting

2007-01-01

110

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

SciTech Connect

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.

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

1982-11-01

111

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

Microsoft Academic Search

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

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

2003-01-01

112

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

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

113

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

Microsoft Academic Search

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

Erik Kellner; Sven Halldin

2002-01-01

114

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

Microsoft Academic Search

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

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

2007-01-01

115

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

Microsoft Academic Search

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

Matteo Sottocornola; Gerard Kiely

2010-01-01

116

Post-Chippewa oxygen isotope record from Cowles Bog, southern Lake Michigan basin  

Microsoft Academic Search

Previous studies of sediments and molluscs recovered from vibracores at Cowles Bog, a fen located in the Indiana Dunes National Lakeshore, along the south shore of Lake Michigan, reveal long and short term water level fluctuations during the last 6000 years. Low water events are indicated by zones of organic detritus, in which occasionally, iron oxide and calcium carbonate nodules,

Barry B. Miller; Michael J. S. Tevesz; Jodie E. Smith

1997-01-01

117

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

Microsoft Academic Search

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.

Michael E. Smith; Jerry L. Kaster

1986-01-01

118

A probe for sampling interstitial waters of stream sediments and bog soils  

USGS Publications Warehouse

A probe for sampling interstitial waters of stream sediments and bog soils is described. Samples can be obtained within a stratigraphic interval of 2-3 cm, to a depth of 60-80 cm, and with little or no contamination of the samples by sediment or air. ?? 1974.

Nowlan, G.A.; Carollo, C.

1974-01-01

119

The role of common upland vegetation on gaseous carbon cycling on UK blanket peat bogs  

Microsoft Academic Search

The most important control upon the carbon dynamics of any peatland is vegetation. However there is a gap in the literature with respect to comparative, in-situ studies of common upland vegetation types on peat bogs from a carbon cycling perspective. Where studies exist they tend to be narrowly focused (i.e. on one or two species or a small geographical area)

Simon Dixon; James Rowson; Fred Worrall

2010-01-01

120

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

Microsoft Academic Search

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

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

1994-01-01

121

Study of speciation and size fractionation of trace element between soil solution, bog, river and lake within a boreal watershed (North Karelia, NW Russia) using fractional filtration  

NASA Astrophysics Data System (ADS)

This work is aimed at studying the evolution of migration forms of true dissolved compounds and colloidal entities using an integrated approach of molecular mass distribution and differences in the association of trace elements (TE) with organic matter (OM) or Fe colloids in the system soil water-bog-river-lake. Characterization of TE speciation with colloids during TE migration from the site of colloids origin (bog and soil solutions) towards the transit zone (river) and finally to the deposition, accumulation or transformation zone (lake) is a main fundamental task of this problem. The objects of study include a small stream watershed Vostochniy and the river Palayoki (North Karelia, Russia). The water samplings were performed in July and August 2008 and 2009 and included soil solution, nourishing bog, the middle part of the brook originated from the swamp, the mouth of the brook and the lake Zipringa. We sampled large volumes (50 - 100 liters), and we applied, directly in the in-field-installed "clean laboratory" the sequential frontal filtration and ultrafiltration of samples through the filters of progressively decreasing poresize 100, 20, 10, 5, 0.8, 0.4, 0.2 and 0.1 microns; 100 kDa (0.0065 micron), 10 kDa (0.003 micron) and 1 kDa (0.0014 micron). This allowed separation of organic matter, coarse and fine particulate matter and colloids. All filtrates and selected retentates were analyzed for a wide range of macro-and micronutrients using ICP-MS. In filtrates of the river water, a significant decrease of iron concentration occurred in the range of 5 micron to 0.22 micron and from 100 kDa to 1 kDa. For alkali and alkaline earth elements (Mg, K, Ca), as well as for Cu, Ni, Cr the concentrations changed after passing through the 10 kDa membrane. Na concentration remains constant in all filtrates. The filtrates of the soil solution are characterized by a significant decreases in Na, K, after 0.1 micron, Ca, Cu in the range of 0.22 micron - 100 kDa and Mg, Ni in the range of 0.1 micron - 100 kDa. The changing of REEs concentrations occurred in the fraction smaller than 100 kDa for river water and in the fraction larger than 100 kDa in the soil solution. Concerning the evolution of element concentration in the system "soil solution - nourishing bog - river - lake", the concentration of Ca and Mg increases (with a little decrease in the stage "the nourishing bog - the middle current - the mouth"), and the concentration of Cu, Ni, Cr, Ti, Al decreases (with a slight increase in the interval "the nourishing swamp - the middle current - the mouth). The lanthanides have a maximum of their concentration in the river mouth and the minimum in the lake. Concentration of Fe, Zn in the soil solution is an order of magnitude higher than in the river and lake water. The ratio Fe / Me (where Me = Al, Cu, Zn, Ni, Co, Cr, Mn) naturally decreases in the course of filtration, whereas the ratio of Fe to Ti increases in a series of consecutive filtrates of soil solution. These observations can be interpreted as a result of interplay between the processes of TE leaching from soil and peat, complexation with colloids in the lake water and microbiological transformation of colloids in the course of the river flow and in the lake water. Results of the present study allow straightforward evaluation of the transformation of TE colloidal status between the site of their origin, migration and consumption (deposition) The work is executed at a Russian Federal Property Fund and CNRS support (?? 08-05-00312_a, 07-05-92212-CNRS_a).

Ilina, Svetlana M.; Lapitsky, Sergey A.; Alekhin, Yuriy V.; Pokrovsky, Oleg S.; Viers, Jerome

2010-05-01

122

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

123

Geology and recognition criteria for uranium deposits of the quartz-pebble conglomerate type. Final report  

SciTech Connect

This report is concerned with Precambrian uraniferous conglomerates. This class of deposit has been estimated to contain between approximately 16 and 35 percent of the global uranium reserve in two rather small areas, one in Canada, the other in South Africa. Similar conglomerates, which are often gold-bearing, are, however, rather widespread, being found in parts of most Precambrian shield areas. Data have been synthesized on the geologic habitat and character of this deposit type. The primary objective has been to provide the most relevant geologic observations in a structural fashion to allow resource studies and exploration to focus on the most prospective targets in the shortest possible time.

Button, A.; Adams, S.S.

1981-03-01

124

Environmental assessment of remedial action at the inactive uraniferous lignite ashing sites at Belfield and Bowman, North Dakota  

SciTech Connect

The Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 authorized the US Department of Energy (DOE) to perform remedial actions at Belfield and Bowman inactive lignite ashing sites in southwestern North Dakota to reduce the potential public health impacts from the residual radioactivity remaining at the sites. The US Environmental Protection Agency (EPA) promulgated standards (40 CFR 192) that contain measures to control the residual radioactive materials and other contaminated materials, and proposed standards to protect the groundwater from further degradation. Remedial action at the Belfield and Bowman sites must be performed in accordance with these standards and with the concurrence of the US Nuclear Regulatory Commission (NRC) and the state of North Dakota. The Belfield and Bowman designated sites were used by Union Carbide and Kerr-McGee, respectively, to process uraniferous lignite in the 1960s. Uranium-rich ash from rotary kiln processing of the lignite was loaded into rail cars and transported to uranium mills in Rifle, Colorado, and Ambrosia Lake, New Mexico, respectively. As a result of the ashing process, there is a total of 158,400 cubic yards (yd{sup 3}) [121,100 cubic meters (m{sup 3})] of radioactive ash-contaminated soils at the two sites. Windblown ash-contaminated soil covers an additional 21 acres (8.5 ha) around the site, which includes grazing land, wetlands, and a wooded habitat.

Not Available

1993-09-01

125

Major and trace element distribution in the peat from ombrotrophic bogs in Latvia.  

PubMed

This study was undertaken to analyse major and trace elements and the nature of their accumulation in peat, with a particular emphasis on peat properties and the impact of local and regional pollution sources on the character of element accumulation in ombrotrophic bogs in Latvia. The element concentration values in peat from Latvia reflect the local processes that affect element concentrations in the peat mass, indicating accumulation of trace elements - apparently of anthropogenic origin (Pb, Cd, Co, Ni and others) - in the upper layers of the peat profiles. In addition, they indicate accumulation of several elements (for example, As, Cr and others) in deeper layers of bog, possibly due to the feeding pattern, depending on the saturation of the groundwater. PMID:21644161

Silamikele, I; Klavins, M; Nikodemus, O

2011-01-01

126

Re-thinking the record: Short-term downwash of Be-7 and Pb-210 in a Swedish peat bog  

NASA Astrophysics Data System (ADS)

The past decade has seen a rapid increase in interest in the biogeochemical record preserved in peat, particularly as it relates to carbon dynamics and environmental changes. However, we still lack a complete understanding of the basic biogeochemical processes and their effect on trace element distributions. Are peat archives an absolute or relative record? What temporal resolution is realistic to interpret by using peat cores? By analyzing atmospherically deposited 210Pb, 137Cs, 241Am and 7Be as well as the trace metals Pb and Hg, in triplicate peat cores from an ombrotrophic Swedish bog we addressed two fundamental issues; the question of representativity of single cores and the incorporation of atmospheric signals in the peat. Both of these issues are of great importance and need to be considered when using peat cores as natural archives. By specifically including the short-lived tracer 7Be (T½ 53.4 days) we tested the hypothesis that downwashing of atmospherically-supplied elements may occur in well aerated peat. Our 210Pb activities all showed a non-monotonic decrease with depth suggesting some downward transport of 210Pb by percolating rainwater. Further to this, the activities of 7Be were detected to 20, 18 and 8 cm depth and there was a lack of any clear peaks in 241Am activities, which together indicate a smearing of the radionuclides to or at the water table. We conclude that this is compelling evidence for a rapid downwash of atmospherically supplied elements in peat, which extends down to the height of water table. By comparing our records to biomonitoring- and direct deposition data we were able to quantify the implications of this downwash on estimates of peat mass accumulation rates and metal (Pb and Hg) deposition. It is clear that under specific conditions the usage of a conventional CRS-dating model can lead to severe overestimations of peat mass accumulation as well as inaccurate estimations of past deposition. However, by applying a new correction model which includes a downward transport term, thereby adjusting the conventional CRS model, we suggest that this downward mobility can be successfully incorporated into age-depth models, allowing more accurate estimations of past deposition and peat accumulation.

Hansson, Sophia; Kaste, James; Olid, Carolina; Bindler, Richard

2013-04-01

127

Unexpectedly low genetic divergences among populations of the threatened bog turtle ( Glyptemys muhlenbergii )  

Microsoft Academic Search

We used mitochondrial DNA sequence comparisons to assess range-wide population structure and historical patterns of differentiation\\u000a among populations of the bog turtle (Glyptemys muhlenbergii). This species is one of North America’s smallest and most endangered pond turtles, and is currently found in three largely\\u000a disjunct groups of populations: in the southern U.S., in the northeast, and in the Finger Lakes

Peter A. Rosenbaum; Jeanne M. Robertson; Kelly R. Zamudio

2007-01-01

128

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

Microsoft Academic Search

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)

Sune Elowson; Lars Rytter

1988-01-01

129

Effects of climate change and human activities on a Swedish raised bog  

Microsoft Academic Search

We determined the effects of climate change and human activities on the species composition of ombrotrophic (rain-fed) peat bogs by analyzing pollen and macrofossils. We used 14C AMS wiggle-match dating (1) to obtain a precise chronology. Thermophilous plant species in the microfossil record provide information on climate change (2). Lime (Tilia), Elm (Ulmus), Beech (Fagus), Hornbeam (Carpinus) and Hazel (Corylus)

Linden van der M

2005-01-01

130

Modelling the effects of climate change on methane emission from a northern ombrotrophic bog in Canada  

Microsoft Academic Search

Peatlands are a large potential source of methane (CH4) to the atmosphere. In order to investigate the effects of climate change on CH4 emission from northern ombrotrophic peatlands, a simulation model coupling water table dynamics with methane emission was\\u000a developed for the Mer Bleue Bog in Ontario, Canada. The model was validated against reported values of CH4 flux from field

Derrick Y. F. Lai

2009-01-01

131

The new European Competence Centre for Moor and Climate - A European initiative for practical peat bog and climate protection  

NASA Astrophysics Data System (ADS)

The new European Competence Centre for Moor and Climate (EFMK) is an initiative by different local communities, environmental protection NGOs, agricultural services, and partners from the peat and other industries in Lower Saxony (Germany). The Centre aims to integrate practical peat bog conservation with a focus on green house gas emission after drainage and after water logging activities. Together with our partners we want to break new ground to protect the remaining bogs in the region. Sphagnum mosses will be produced in paludiculture on-site in cooperation with the local peat industry to provide economic and ecologic alternatives for peat products used in horticulture business. Land-use changes are needed in the region and will be stimulated in cooperation with agricultural services via compensation money transfers from environmental protection funds. On a global scale the ideas of Carbon Credit System have to be discussed to protect the peat bogs for climate protection issues. Environmental education is an important pillar of the EFMK. The local society is invited to explore the unique ecosystem and to participate in peat bog protection activities. Future generations will be taught to understand that the health of our peat bogs is interrelated with the health of the local and global climate. Besides extracurricular classes for schools the centre will provide infrastructure for Master and PhD students, as well for senior researchers for applied research in the surrounding moor. International partners in the scientific and practical fields of peat bog ecology, renaturation, green house gas emissions from peat bogs, and environmental policy are invited to participate in the European Competence Center for Moor and Climate.

Smidt, Geerd; Tänzer, Detlef

2013-04-01

132

[Bacteria of the genus Burkholderia as a typical component of the microbial community of sphagnum peat bogs].  

PubMed

Bacteria of the genus Burkholderia are a typical component of the microbial complex of sphagnum peat bogs and constitute a substantial portion of the aerobic chemoorganotrophic isolates which are routinely obtained from these environments on acidic nutrient media. The ecophysiological characteristics of the 27 strains of such organisms, which were isolated from the peat of acidic sphagnum bogs of the boreal and tundra zones of Russia, Canada, and Estonia, were investigated in the present paper. The overwhelming majority of the Burkholderia strains isolated from these bogs were phylogenetically close to the species B. glathei, B. phenazinium, B. fungorum, and B. caryophylli, the typical inhabitants of soil and plant rhizosphere. The bog isolates utilized a broad range of substrates as carbon and energy sources, including organic acids, sugars, polyalcohols, and certain aromatic compounds. All the strains studied were capable of growth on nitrogen-free media. They developed in the pH ranges of 3.5 to 7.4 and from 3 to 37 degrees C, with the optima at pH 5-7 and 11-23 degrees C, respectively. They were therefore moderately acidophilic, psychroactive, dinitrogen-fixing microorganisms well adapted to the conditions of acidic northern sphagnum bogs. PMID:16579452

Belova, S E; Pankratov, T A; Dedysh, S N

2006-01-01

133

Raised bogs, a Climate Shift, Cultural Change, and Reduced Solar Activity in the Early First Millennium BC  

NASA Astrophysics Data System (ADS)

Matching of a high resolution sequence of uncalibrated 14C datings with the dendro-calibration curve not only offers improved dating precision, but can also reveal relationships between atmospheric 14C variations and short-term climatic fluctuations caused by variations in solar output. Holocene shifts to cool and wet climate types in the temperate zones often correspond to phases of sharply increasing values of atmospheric radiocarbon, pointing to a link between changing solar activity and climate change. In northwest Europe at ca. 850 BC a sharp climatic shift to cooler, wetter conditions occurred. The shift is reflected in the species composition and decomposition of raised bog deposits and is chronologically linked to cultural changes and migrations at the Bronze Age/Iron Age transition. The temporary sharp rise of the atmospheric 14C content around 800 BC was caused by a sudden decline of solar activity. The solar wind declined, permitting more cosmic rays to penetrate into the atmosphere, and therefore the production of the cosmogenic isotope 14C increased. The climate shift was also recorded in Central and Eastern Europe, with rapid and total flooding of the Upper Volga region and a highstand of the Caspian Sea. In the Mississippi River basin, flooding frequencies greatly increased and there was an abrupt gap in the cultural transition from `Late Archaic' to `Early Woodland'. Paleoclimatological teleconnections point to a considerable role of solar UV in climate forcing. In the Central African rain forest belt and western India there was also a strong climate shift around 850 cal BC, but it was a shift to dryness (weakening of the summer monsoon). A possible palaeoclimatological explanation for the dry-wet transition in the temperate zones, and the contemporaneous wet-dry transition in the tropics (climatic teleconnections) will be given.

van Geel, B.

2006-12-01

134

The geochemistry of major and selected trace elements in two peat profiles from ridge-hollow complex of southeastern spurs of Vasyugan bog, southern taiga zone of West Siberia  

NASA Astrophysics Data System (ADS)

The main goal of this paper is to describe and discuss the concentrations and distributions of the major (Si, Al, Ca, Mg, Fe, K) and some trace (Sr, Ba, Mn, Cu, Co, Cr, Ni, Pb) elements during the Holocene from two peat bog profiles of ridge-hollow complex in the southeastern spurs of Vasyugan bog. One of them was formed on the ridge; the second - in the depression and is currently being developed for the type of hollow. The peat accumulation in the ridge and in the hollow started ~2477±80 and ~4774 ± 80 before present (BP), respectively. The average concentrations of Mg, Al, S, Sr, Cu, Ni is about 2-3 times higher in the peat profile from hollow then in the ridge profile. The other element concentrations from both profiles are comparable. The distributions of element concentrations and ash content in the peat profiles are in a good agreement. The element distributions show significantly similar patterns in profiles. Two dominant peaks were found: first peak is between 10 and 50 cm, second peak is between 150-170 cm in the ridge profile and between 180-200 cm in the hollow profile. The origin of the peaks in the middle part of the both profiles at almost the same time: between 2272 and 2190 cal. BP, but no later than 2112 ± 55 BP. These peaks cannot be explained by chemical diagenesis because they are too far above the underlying sediments of the peat profiles, and too far below the uppermost layers. We assume that the increase of elements content reflects the chemical composition of airborne materials supplied to the surface layers of the bog at the time deposition.

Veretennikova, Elena

2013-04-01

135

Reconstructing the environmental impact of smelters using Pb isotope analyses of peat cores from bogs: Flin Flon, Manitoba and Harjavalta, Finland  

NASA Astrophysics Data System (ADS)

Located on the Manitoba - Saskatchewan border, the city of Flin Flon has been home to a metallurgical complex since 1930, processing Cu and Zn ores from surrounding mines and consisting of a concentrator, Zn plant, and Cu smelter. Peat cores were collected from two sites, dated using 210Pb, and measured for a broad suite of potentially toxic trace metals. A peat core collected from the bog at Kotyk Lake (30 km NE of FF) shows declines in 206Pb/207Pb from the natural "background" values of 1.25 at the base of the core, to a minimum of 1.02. A peat core collected from the bog at Sask Lake (88 km NW of FF) shows declines in 206Pb/207Pb from the natural "background" values of 1.35 at the base of the core to a minimum of 1.05. But the isotopic evolution of Pb shows significantly declines in 206Pb/207Pb beginning in the late 1800's, presumably because of long-range atmospheric transport from other sources. The 206Pb/207Pb values increase in both cores starting in the 1960's, and reach a recent maximum in the 1990's, apparently reflecting the growing use and eventually phase out of leaded gasoline use. Since the 1990's, the 206Pb/207Pb have continued their decline, apparently reflecting the elimination of leaded gasoline and the growing relative importance of Pb from the smelter. The temporal evolution in Pb enrichment factors follows the history of the metallurgical complex, with the maximum EF values (calculated using Sc) reaching maxima of ca. 100 x (Kotyk Lake) and 10 x (Sask Lake). The maximum rates of atmospheric Pb accumulation are approximately 1200 and 120 ?g/m2/yr, respectively. In Finland, peat cores were taken from three bogs: the Pyhäsuo mire in SW Finland, 6 km NE from the Cu Ni smelter at Harjavalta (HAR); at the Viurusuo complex in eastern Finland, 8 km SW of the Cu Ni mine in the town of Outokumpu (OUT); and at Hietajärvi (HJ), in the Patvinsuo National Park of eastern Finland. The cores from HJ and OUT document 3,000 years of anthropogenic Pb and provide a remarkably similar evolution of Pb isotopes, reaching values as low as 206Pb/207Pb = 1.151 (AD 1982) and 1.148 (AD 1984), respectively. At HAR, the minimum values are lower (206Pb/207Pb = 1.120) and earlier (AD 1954 -1967), presumably because of emissions from the smelter. The Pb concentrations in the porewaters from HAR are approximately an order of magnitude greater than the other sites, and the 206Pb/207Pb values significantly lower (ca. 1.12 vs. 1.15), because of the combined effects of greater Pb deposition and surface water acidification (pH 3.5 versus pH 4.0 in the other bogs).

Shotyk, W.

2012-04-01

136

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

Microsoft Academic Search

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

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

1999-01-01

137

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

Microsoft Academic Search

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

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

2006-01-01

138

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

PubMed Central

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

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

2012-01-01

139

App. 1-5. Internet supplement to: Benscoter, B.W.; Kelman Wieder, R. & Vitt, D.H. 2005. Linking microtopography with post-fire succession in bogs  

E-print Network

microtopography with post-fire succession in bogs J. Veg. Sci. 16: 453-460. App. 1a. Characteristics used.W.; Kelman Wieder, R. & Vitt, D.H. 2005. Linking microtopography with post-fire succession in bogs J. Veg (morphology follows, in part, Lévesque et al. 1988). Classification Characteristics Woody debris Bark Rough

Benscoter, Brian W.

140

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

Microsoft Academic Search

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

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

2007-01-01

141

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

NASA Astrophysics Data System (ADS)

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

McKenzie, Jeffrey M.; Siegel, Donald I.; Rosenberry, Donald O.; Glaser, Paul H.; Voss, Clifford I.

2007-01-01

142

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

PubMed Central

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

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

2006-01-01

143

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

144

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

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.

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

2006-01-01

145

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

Microsoft Academic Search

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

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

2011-01-01

146

Effects of Flooding on the Carbon and Nitrogen Cycles in the Cedar, Maple, and Pine Bogs of  

E-print Network

Effects of Flooding on the Carbon and Nitrogen Cycles in the Cedar, Maple, and Pine Bogs of Western the carbon and nitrogen cycles under the duress of flooding and drainage, a manipulative experiment was set was not able to fully assess the carbon and nitrogen cycles, but it did show that theses systems are very rich

Vallino, Joseph J.

147

A Holocene record of climate, vegetation change and peat bog development, east Otago, South Island, New Zealand  

NASA Astrophysics Data System (ADS)

A Holocene record of pollen, macrofossils, testate amoebae and peat humification is presented from a small montane bog. Sediment accumulation began before 9000 yr BP, but peat growth not until ca. 7000 BP. From 12 000 to 7000 yr BP, a shrub-grassland dominated under a dry climate, with increasing conifer forest and tall scrub from ca. 9600 yr BP. At 7000 yr BP a dense montane-subalpine low conifer forest established under a moist, cool climatic regime. Between 7000 and 700 yr BP the bog surface was shrubby, tending to be dry but with highly variable surface wetness. The catchment was affected by major fire at least four times between 4000 and 1000 yr BP. Both fire and bog surface wetness may have been linked to ENSO-caused variations in rainfall. Cooler, cloudier winters and disturbance by fire promoted the expansion of the broadleaf tree Nothofagus menziesii between 4000 yr BP and 1300 yr BP at the expense of the previous conifer forest-scrub vegetation. Polynesian fires (ca. 700 yr BP) reduced the vegetation to tussock grassland and bracken. Deforestation did not markedly affect the hydrology of the site. European pastoralism since ad 1860 has increased run-off and rising water tables in the bog have led to a Sphagnum-dominated cover.

McGlone, Matt S.; Wilmshurst, Janet M.

1999-05-01

148

Assessing the impact of wind farms on the plant diversity of blanket bogs in the Xistral Mountains (NW Spain)  

Microsoft Academic Search

SUMMARY The work reported in this paper explored the effects of wind farms on the plant species and vegetation diversity of summits and slopes in the Xistral Mountains, where priority habitats occur (EU Habitats Directive, code 7130 blanket bog). Quantitatively, our results showed significantly lower ? diversity and higher ? diversity in impacted areas when compared to non-impacted areas. These

M. I. Fraga; D. Romero-Pedreira; M. Souto; D. Castro; E. Sahuquillo

149

CO2 fluxes at northern fens and bogs have opposite responses to inter-annual fluctuations in water table  

Microsoft Academic Search

This study compares eddy-covariance measurements of carbon dioxide fluxes at six northern temperate and boreal peatland sites in Canada and the northern United States of America, representing both bogs and fens. The two peatland types had opposite responses of gross ecosystem photosynthesis (GEP) and ecosystem respiration (ER) to inter-annual fluctuations in water table level. At fens, wetter conditions were correlated

Benjamin N. Sulman; Ankur R. Desai; Nicanor Z. Saliendra; Peter M. Lafleur; Lawrence B. Flanagan; Oliver Sonnentag; D. Scott Mackay; Alan G. Barr; Garth van der Kamp

2010-01-01

150

Modeling regional groundwater flow in a peat bog complex in Ontario, Canada  

NASA Astrophysics Data System (ADS)

Peatlands are important ecohydrological systems and contribute significantly to the global carbon cycle. They function as carbon sinks through CO2-sequestration but also emit methane depending i.a. on the prevailing hydrological structures. Knowledge of their hydrology including exchange between the groundwater and surface water domain is thus necessary to understand wetland environments and to determine their vulnerability to climate changes. The impact of proposed wetter conditions on wetland hydrological homeostastis in northern bogs is uncertain to this date. Elevated water tables due to changing hydrological flow patterns may affect the characteristics of wetlands as a carbon reservoir. Modeling approaches allow quantifying and qualifying of these flow patterns on a longer time scale. Luther Bog is located in Southern Ontario. The ombotrophic bog to poor fen is partially bordered by Luther Lake which inundates the area since its creation in 1952. In this study the interaction between the wetland and the adjacent lake is modeled using the fully-integrated HydroGeoSphere model. A transient three-dimensional groundwater mode is set up for a small catchment with the lake level implemented as a constant-head boundary condition. Hydraulic properties of the peat were estimated executing bail tests on multilevel piezometers at different sites within the wetland. The first hypothesis is that the wet conditions in the runoff network keep the water table in the wetland high over a specific transition zone. The Second is that there may be a reversal of flow directions over the hydrological year, due to varying boundary conditions, e.g. evapotranspiration and precipitation. First results indicate that exchange rates may be very slow. This is supported by manual measurements of little hydraulic gradients and little topographic gradients. The results also show a seasonal effect in flow directions in both, the groundwater and the surface water domain. The model will be tested upon its sensitivity to variations in the anisotropy of hydraulic conductivities as this is difficult to determine in the field using known approaches, e.g. bail tests. A transport simulation will be conducted to determine the exact amount of exchange water and the extent of the exchange zone.

Durejka, Stefan; Knorr, KLaus-Holger; Blodau, Christian; Frei, Sven

2013-04-01

151

Effects of land use intensity on the full greenhouse gas balance in an Atlantic peat bog  

NASA Astrophysics Data System (ADS)

The assessment of emission factors for many peatlands is difficult, and reliable data on the exchange of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) between soil and atmosphere of these areas is particularly scarce. Reasons for this are the multitude of soil and land use combinations that control greenhouse gas exchange and the high effort associated with data acquisition. We investigated the greenhouse gas exchange of a peat bog restoration sequence over a period of 2 yr (July 2007-June 2009) in an Atlantic raised bog in Northwest Germany. We set up three sites representing different land use intensities: intensive grassland (mineral fertilizer, cattle manure and 4-5 cuts per year); extensive grassland (no fertilizer or manure, maximal 1 cutting per year); near-natural peat bog (almost no anthropogenic influence). We obtained seasonal and annual estimates of greenhouse gas exchange based on closed chamber measurements. CH4 and N2O fluxes were recorded bi-weekly, CO2 NEE determinations were carried out 3-4 weekly. To get annual sums the CH4 and N2O fluxes were interpolated linearly while NEE was modelled. The intensive grassland site emitted 548 ± 169 g CO2-C m-2 in the first and 817 ± 140 g CO2-C m-2 in the second year. The extensive grassland site showed a slight uptake in the first year (-148 ± 143 g CO2-C m-2), and a small emission of 88 ± 146 g CO2-C m-2 in the second year. In contrast to these agriculturally used sites, the near-natural site took up CO2-C in both years (-8 ± 68 g CO2-C m-2 and -127 ± 53 g CO2-C m-2). Under consideration of N2O and CH4 exchange, the total average greenhouse warming potential (GWP) for 2008 amounts to 441 ± 157 g m-2, 14 ± 152 g m-2 and 31 ± 68 g m-2 CO2-C-equivalent for the intensive grassland, the extensive grassland and the near-natural site, respectively. Despite inter-annual variability, rewetting contributes considerably to mitigating GHG emission from formerly drained peatlands. Already extensively used grassland on moderately drained peat approaches the carbon sequestration potential of near-natural sites, albeit it may oscillate between being a small sink and being a small source depending on interannual climatic variability.

Beetz, S.; Liebersbach, H.; Glatzel, S.; Jurasinski, G.; Buczko, U.; Höper, H.

2012-06-01

152

The role of common upland vegetation on gaseous carbon cycling on UK blanket peat bogs  

NASA Astrophysics Data System (ADS)

The most important control upon the carbon dynamics of any peatland is vegetation. However there is a gap in the literature with respect to comparative, in-situ studies of common upland vegetation types on peat bogs from a carbon cycling perspective. Where studies exist they tend to be narrowly focused (i.e. on one or two species or a small geographical area) or are laboratory manipulation studies. This study set out to compare gaseous CO2 exchange, in situ, across a broad (geographic) range of sites dominated by differing, common, upland vegetation types. The vegetation types studied were; Calluna vulgaris, Sphagnum spp., Eriophorum (E. angustifolium + E. vaginatum), Molinia caerulea and areas revegetated with a lawn grass mixture that was used for restoration (Festuca spp, Deschampsia spp. and Agrostis spp.).The primary aim of the study was to assess the carbon cycling potential of the common upland vegetation types, in order to produce clearer evidence as to which upland species produce the most efficient carbon sinks. The study was carried out in the South Pennines and Peak District of England. All readings were taken from upland-blanket peat bogs, as this type of bog accounts for 87% of the UK's peatlands, and therefore the results of this study can have the widest possible applicability to the rest of the UK's peat reserves. NEE and NER measurements were taken with a PP Systems EMG-4 infra-red gas analyzer. PAR and air temperature readings were taken along side water table and soil pore water samples from every site. Each site was visited monthly for at least 12 months and between 3-9 replicates were recorded per site. The results of this study will deal with the effects vegetation has on NER, GPP and NEE, focusing on which vegetation types make the most efficient gaseous carbon sinks. Moreover the effect of vegetation on water table levels and water quality will be discussed. Finally a consideration of how the age of Calluna vulgaris affects the parameters above will be given.

Dixon, Simon; Rowson, James; Worrall, Fred

2010-05-01

153

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

NASA Astrophysics Data System (ADS)

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. Due to the chemically undefined nature of many humification analyses the comparison of results obtained by different methods is difficult if not misleading. In this study we compared changes in peat decomposition 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 Eval® oxygen- and hydrogen indices, ?13C and ?15N isotopic signatures and UV-absorption of NaOH peat extracts. In addition, one of the cores was analysed for changes in the peat's molecular composition using pyrolysis gas chromatography mass spectrometry (pyrolysis-GC-MS). Records of decomposition proxies show similar historical development at both sites, indicating external forcing such as climate as controlling process. Moreover, all decomposition proxies except UV-ABS and ?15N isotopes show similar patterns in their records and thus reflect in different extents signals of decomposition. Pyrolysis-GC-MS analyses of the KK core reveal that changes in peat molecular chemistry are mainly attributed to decomposition processes and to a lesser extend to changes in vegetation. Changes in the abundance of molecular compounds 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, and presumably reflects changes in vegetation associated to 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 despite their bulk nature. Correlation 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. Different to the other investigated proxies, Pyrolysis-GC-MS and FTIR analyses allow disentangling decomposition processes and vegetation changes. UV-ABS measurements of alkaline peat extracts show only weak correlation with other decomposition proxiesas they mainly reflect the formation of humic acids through humifcation and to a~lesser extend mass loss during mineralization.

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

2013-11-01

154

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

NASA Astrophysics Data System (ADS)

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.

Kellner, Erik; Halldin, Sven

2002-01-01

155

Origin of lead in eight Central European peat bogs determined from isotope ratios, strengths, and operation times of regional pollution sources.  

PubMed

Lead originating from coal burning, gasoline burning, and ore smelting was identified in 210Pb-dated profiles through eight peat bogs distributed over an area of 60,000 km2. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering with Germany, Austria, and Poland. Basal peat 14C-dated at 11,000 years BP had a relatively high 206Pb/207Pb ratio (1.193). Peat deposited around 1800 AD had a lower 206Pb/207Pb ratio of 1.168-1.178, indicating that environmental lead in Central Europe had been largely affected by human activity (smelting) even before the beginning of the Industrial Revolution. Five of the sites exhibited a nearly constant 206Pb/207Pb ratio (1.175) throughout the 19th century, resembling the "anthropogenic baseline" described in Northern Europe (1.17). At all sites, the 206Pb/207Pb ratio of peat decreased at least until 1980; at four sites, a reversal to more radiogenic values (higher 206Pb/207Pb), typical of easing pollution, was observed in the following decade (1980-1990). A time series of annual outputs for 14 different mining districts dispersing lead into the environment has been constructed for the past 200 years. The production of Ag-Pb, coal, and leaded gasoline peaked in 1900, 1980, and 1980, respectively. In contrast to other European countries, no peak in annual Pb accumulation rates was found in 1900, the year of maximum ore smelting. The highest annual Pb accumulation rates in peat were consistent with the highest Pb emission rates from coal-fired power plants and traffic (1980). Although maximum coal and gasoline production coincided in time, their isotope ratios were unique. The mean measured 206Pb/207Pb ratios of local coal, ores, and gasoline were 1.19, 1.16, and 1.11, respectively. A considerable proportion of coal emissions, relative to gasoline emisions, was responsible for the higher 206Pb/207Pb ratios in the recent atmosphere (1.15) compared to Western Europe (1.10). As in West European countries, the gasoline sold in the Czech Republic during the Communist era (1948-1989) contained an admixture of low-radiogenic Precambrian lead from Australia. PMID:12630456

Novák, Martin; Emmanuel, Simon; Vile, Melanie A; Erel, Yigal; Véron, Alain; Paces, Tomás; Wieder, R Kelman; Vanecek, Mirko; Stepánová, Markéta; Brízová, Eva; Hovorka, Jan

2003-02-01

156

The Geochronology of Uraniferous Minerals in the Witwatersrand Triad; an Interpretation of New and Existing UPb Age Data on Rocks and Minerals from the Dominion Reef, Witwatersrand and Ventersdorp Supergroups  

Microsoft Academic Search

Uranium and lead analyses of rock samples from the Witwatersrand, Ventersdorp, and Transvaal supergroups give mainly discordant ages. Samples from the Upper Witwatersrand of the Orange Free State give 207Pb\\/206Pb ages of ca. 3000 Ma. These data when considered together with earlier total conglomerate U-Pb analyses from the Dominion Reef Supergroup lead to the conclusion that the uraniferous minerals of

C. C. Rundle; N. J. Snelling

1977-01-01

157

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

Microsoft Academic Search

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,

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

1984-01-01

158

Parameter Calculation Technique for the Waste Treatment Facilities Using Naturally-Aerated Blocks in the Bog Ecosystems  

NASA Astrophysics Data System (ADS)

Technique for the domestic wastewater treatment in the small residential areas and oil and gas facilities of the natural and man-made systems including a settling tank for mechanical treatment and a biological pond with peat substrate and bog vegetation for biological treatment has been substantiated. Technique for parameters calculation of the similar natural and man-made systems has been developed. It was proven that effective treatment of wastewater can be performed in Siberia all year round.

Akhmed-Ogly, K. V.; Savichev, O. G.; Tokarenko, O. G.; Pasechnik, E. Yu; Reshetko, M. V.; Nalivajko, N. G.; Vlasova, M. V.

2014-08-01

159

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

Microsoft Academic Search

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

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

2007-01-01

160

Disturbances on a Wooded Raised Bog—How Windthrow, Bark Beetle and Fire Affect Vegetation and Soil Water Quality?  

Microsoft Academic Search

Pinus rotundata dominated peatbog (Žofinka Nature Reserve) in the T?ebo? Basin, Czech Republic, was affected by “natural” disturbances: wind\\u000a damage (1984), followed by a bark beetle attack, and fire (1994, 2000). Phytosociological relevés were used to document vegetation.\\u000a Soil water chemistry was compared in three differently affected stands: (1) an undisturbed Pinus rotundata bog forest, (2) a windthrow – bark

Andrea Ku?erová; Ladislav Rektoris; Tá?a Štechová; Marek Bastl

2008-01-01

161

Contrasting Species—Environment Relationships in Communities of Testate Amoebae, Bryophytes and Vascular Plants Along the Fen–Bog Gradient  

Microsoft Academic Search

We studied the vegetation, testate amoebae and abiotic variables (depth of the water table, pH, electrical conductivity, Ca\\u000a and Mg concentrations of water extracted from mosses) along the bog to extremely rich fen gradient in sub-alpine peatlands\\u000a of the Upper Engadine (Swiss Alps). Testate amoeba diversity was correlated to that of mosses but not of vascular plants.\\u000a Diversity peaked in

Mariusz Lamentowicz; ?ukasz Lamentowicz; Willem O. van der Knaap; Maciej G?bka; Edward A. D. Mitchell

2010-01-01

162

Effects of land use intensity on the full greenhouse gas balance in an Atlantic peat bog  

NASA Astrophysics Data System (ADS)

Wetlands can either be net sinks or net sources of greenhouse gases (GHGs), depending on the mean annual water level and other factors like average annual temperature, vegetation development, and land use. Whereas drained and agriculturally used peatlands tend to be carbon dioxide (CO2) and nitrous oxide (N2O) sources but methane (CH4) sinks, restored (i.e. rewetted) peatlands rather incorporate CO2, tend to be N2O neutral and release CH4. One of the aims of peatland restoration is to decrease their global warming potential (GWP) by reducing GHG emissions. We estimated the greenhouse gas exchange of a peat bog restoration sequence over a period of 2 yr (1 July 2007-30 June 2009) in an Atlantic raised bog in northwest Germany. We set up three study sites representing different land use intensities: intensive grassland (deeply drained, mineral fertilizer, cattle manure and 4-5 cuts per year); extensive grassland (rewetted, no fertilizer or manure, up to 1 cutting per year); near-natural peat bog (almost no anthropogenic influence). Daily and annual greenhouse gas exchange was estimated based on closed-chamber measurements. CH4 and N2O fluxes were recorded bi-weekly, and net ecosystem exchange (NEE) measurements were carried out every 3-4 weeks. Annual sums of CH4 and N2O fluxes were estimated by linear interpolation while NEE was modelled. Regarding GWP, the intensive grassland site emitted 564 ± 255 g CO2-C equivalents m-2 yr-1 and 850 ± 238 g CO2-C equivalents m-2 yr-1 in the first (2007/2008) and the second (2008/2009) measuring year, respectively. The GWP of the extensive grassland amounted to -129 ± 231 g CO2-C equivalents m-2 yr-1 and 94 ± 200 g CO2-C equivalents m-2 yr-1, while it added up to 45 ± 117 g CO2-C equivalents m-2 yr-1 and -101 ± 93 g CO2-C equivalents m-2 yr-1 in 2007/08 and 2008/09 for the near-natural site. In contrast, in calendar year 2008 GWP aggregated to 441 ± 201 g CO2-C equivalents m-2 yr-1, 14 ± 162 g CO2-C equivalents m-2 yr-1 and 31 ± 75 g CO2-C equivalents m-2 yr-1 for the intensive grassland, extensive grassland, and near-natural site, respectively. Despite inter-annual variability, rewetting contributes considerably to mitigating GHG emission from formerly drained peatlands. Extensively used grassland on moderately drained peat approaches the carbon sequestration potential of near-natural sites, although it may oscillate between being a small sink and being a small source depending on inter-annual climatic variability.

Beetz, S.; Liebersbach, H.; Glatzel, S.; Jurasinski, G.; Buczko, U.; Höper, H.

2013-02-01

163

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

NASA Astrophysics Data System (ADS)

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.

Mezhibor, Antonina; Podkozlin, Ivan

2013-04-01

164

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

NASA Astrophysics Data System (ADS)

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.

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

2003-04-01

165

Superfund record of decision (EPA Region 2): Burnt Fly Bog, Marlboro Township, NJ, September 30, 1998  

SciTech Connect

This decision document presents the selected remedial action for the Westerly Wetlands, Northerly Wetlands, and Tar Patch Area at the Burnt Fly Bog Superfund Site. It addresses contaminated soil present on the three remaining contaminated areas on the Site, including the Westerly Wetlands, Northerly Wetlands, and Tar Patch Area. The major components of the selected remedy include: Excavation and off-site disposal of contaminated soil from the Northerly Wetlands; Excavation and off-site disposal of contaminated soil from the Tar Patch Area; Backfilling the excavated area in the Northerly Wetland and reestablishing wetlands; Backfilling the excavated area in the Tar Patch Area and creating wetlands; Provision of additional security fencing around the Westerly Wetlands, and the recording of a Deed Notice for the Westerly Wetlands, Northerly Wetlands, and Tar Patch Area; Monitoring of surface water and sediment in the Westerly Wetlands, surface water and sediment in the existing sedimentation basin located in the Downstream Area, and surface water, sediment and, if necessary, biota in Burnt Fly Brook; and Biological sampling in the Westerly Wetlands.

NONE

1999-03-01

166

Ecosystem Phenology from Eddy-covariance Measurements: Spring Photosynthesis in a Cool Temperate Bog  

NASA Astrophysics Data System (ADS)

The onset and increase of spring photosynthetic flux of carbon dioxide is an important attribute of the carbon budget of northern ecosystems and we used eddy-covariance measurements from March to May over 5 years at the Mer Bleue ombrotrophic bog to establish the important controls. The onset of ecosystem photosynthesis (day-of-year from 86 to 101) was associated with the disappearance on the snow cover and there is evidence that photosynthesis can continue after a thin new snowfall. The growth of photosynthesis during the spring period was partially associated with light (daily photosynthetically active radiation) but primarily with temperature, with the strongest correlation being observed with peat temperature at a depth of 5 and 10 cm, except in one year in which there was a long snow cover. The vegetation comprises mosses, which are able to photosynthesize very early, evergreen shrubs, which appear dependent on soil warming, and deciduous shrubs, which leaf-out only in late spring. We observed changes in shrub leaf colour from brown to green and concomitant increases in foliar nitrogen and chlorophyll concentrations during the spring in this "evergreen" system. We analyzed MODIS images for periods of overlap of tower and satellite data and found a generally strong correlation, though the infrequent satellite measurements were unable to pick out the onset and timing of rapid growth of photosynthesis in this ecosystem.

Lafleur, P.; Moore, T. R.; Poon, D.; Seaquist, J.

2005-12-01

167

Variation in methane production pathways associated with permafrost decomposition in collapse scar bogs of Alberta, Canada  

NASA Astrophysics Data System (ADS)

Stable isotope analysis was used to determine the distribution of methanogenic pathways at permafrost collapse scar bogs to test the hypothesis that microbial respiration and methane production are stimulated by the input of organic matter associated with permafrost degradation and collapse. An alternative hypothesis is that recently assimilated carbon produced by the fen-like vegetation (Carex, Eriophorum) growing in open water moats formed by the collapsing edge of these features stimulates microbial respiration. We found that CO2 reduction was the dominant pathway for methanogenesis within the Sphagnum areas that dominate the surface cover of these features, but relatively more acetate fermentation occurred near collapse scar moats. Methane emission and net CO2 uptake were correlated. Both were elevated in collapse scar moats and then decreased along a transect from the moats toward the center Sphagnum-dominated areas. There also appeared to be a shift toward relatively more acetate fermentation in deeper samples associated with increasing cation (calcium and magnesium) concentrations. Our results indicate that organic inputs from permafrost degradation alone do not appear to stimulate acetate fermentation. Permafrost decomposition provides conditions along the collapsing edge that are conducive to colonization by fen-like vegetation that stimulates acetate fermentation and increases methane production and emission rates.

Prater, James L.; Chanton, Jeffrey P.; Whiting, Gary J.

2007-12-01

168

Novosphingobium aquaticum sp. nov., isolated from the humic-matter-rich bog lake Grosse Fuchskuhle.  

PubMed

A yellow-pigmented, Gram-negative rod, designated FNE08-86(T), was isolated from subsurface water of the humic-matter-rich and almost-neutral north-east basin of the experimentally divided bog lake Grosse Fuchskuhle (Brandenburg, Germany). Analysis of the nearly full-length 16S rRNA gene sequence showed the highest 16S rRNA gene sequence similarity with Novosphingobium rosa IAM 14222(T) (96.3 %). Sequence similarities with all other members of the genus Novosphingobium species were <96 %, but phylogenetic tree construction clearly showed the placement of strain FNE08-86(T) within the genus Novosphingobium. The predominant fatty acids were C18 : 1?7c and C16 : 0, and only a single 2-hydroxy fatty acid, C14 : 0 2-OH, was detected. The polar lipid profile revealed phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine as major compounds, with smaller amounts of sphingoglycolipid, phosphatidylmonomethylethanolamine, diphosphatidylglycerol and several unidentified lipids. In the quinone system ubiquinone Q-10 was predominant and in the polyamine pattern spermidine was predominant. Characterization by genotypic, chemotaxonomic and phenotypic analysis indicated that strain FNE08-86(T) represents a novel species of the genus Novosphingobium, for which we propose the name Novosphingobium aquaticum sp. nov. (type strain FNE08-86(T) = DSM 25088(T) = CCM 7983(T)). PMID:23264506

Glaeser, Stefanie P; Bolte, Kathrin; Busse, Hans-Jürgen; Kämpfer, Peter; Grossart, Hans-Peter; Glaeser, Jens

2013-07-01

169

Atmospheric methane sources - Alaskan tundra bogs, an alpine fen, and a subarctic boreal marsh  

NASA Technical Reports Server (NTRS)

Methane (CH4) flux measurements from Alaska tundra bogs, an alpine fen, and a subarctic boreal marsh were obtained at field sites ranging from Prudhoe Bay on the coast of the Arctic Ocean to the Alaskan Range south of Fairbanks during August 1984. In the tundra, average CH4 emission rates varied from 4.9 mg CH4 per sq m per day (moist tundra) to 119 mg CH4 per sq m per day (waterlogged tundra). Fluxes averaged 40 mg CH4 per sq m per day from wet tussock meadows in the Brooks Range and 289 mg Ch4 per sq m per day from an alpine fen in the Alaskan Range. The boreal marsh had an average CH4 emission rate of 106 mg CH4 per sq m per day. Significant emissions were detected in tundra areas where peat temperatures were as low as 4 C, and permafrost was only 25 cm below the ground surface. Emission rates from the 17 sites sampled were found to be logarithmically related to water levels at the sites. Extrapolation of the data to an estimate of the total annual CH4 emission from all arctic and boreal wetlands suggests that these ecosystems are a major source of atmospheric CH4 and could account for up to 23 percent of global CH4 emissions from wetlands.

Sebacher, D. I.; Harriss, R. C.; Grice, S. S.; Bartlett, K. B.; Sebacher, S. M.

1986-01-01

170

The Permo-Triassic uranium deposits of Gondwanaland  

NASA Astrophysics Data System (ADS)

The world's uranium provinces are time bound and occur in five distinct periods ranging from the Proterozoic to the Recent. One of these periods embraces the time of Gondwana sedimentation and probably is related to the proliferation of land plants from the Devonian on-ward. Decaying vegetal matter produced reducing conditions that enhanced uranium precipitation. The association of uranium with molassic basins adjacent to uplifted granitic and volcanic arcs suggests that lithospheric plate subduction, leading to anatexis of basement rocks and andesitic volcanism, created favorable conditions for uranium mineralization. Uranium occurrences of Gondwana age are of four main types: sandstone-hosted, coal-hosted, pelite-hosted, and vein-type deposits. Sandstone-hosted deposits commonly occur in fluviodeltaic sediments and are related to the presence of organic matter. These deposits commonly are enriched in molybdenum and other base metal sulfides and have been found in South Africa, Zimbabwe, Zambia, Angola, Niger, Madagascar, India, Australia, Argentina, and Brazil. Coalhosted deposits contain large reserves of uranium but are of low grade. In Africa they are mostly within the Permian Ecca Group and its lateral equivalents, as in the Springbok Flats, Limpopo, Botswana, and Tanzania basins. Uraniferous black shales are present in the Gabon and Amazon basins but grades are low. Vein-type uranium is found in Argentina, where it occurs in clustered veins crosscutting sedimentary rocks and quartz porphyries.

le Roux, J. P.; Toens, P. D.

171

Bog bilberry anthocyanin extract improves motor functional recovery by multifaceted effects in spinal cord injury.  

PubMed

The aim of this study was to determine the therapeutic efficiency of bog bilberry anthocyanin extract (BBAE) treatment starting 1 d after spinal cord injury (SCI) in rats and to investigate the underlying mechanism. The BBAE contained cyanidin-3-glucoside, malvidin-3-galactoside and malvidin-3-glucoside. SCI models were induced using the weight-drop method in Sprague-Dawley rats and additionally with sham group (laminectomy only). The animals were divided into four groups: vehicle-treated group; 10 mg/kg BBAE-treated group; 20 mg/kg BBAE-treated group; sham group. BBAE-treated or vehicle-treated group was administered orally at one day after SCI and then daily for 8 weeks. Locomotor functional recovery was assessed during the 8 weeks post operation period by performing a Basso, Beattie, and Bresnahan (BBB) locomotor score test. At the end of study, the animals were killed, and 1.5 cm segments of spinal cord encompassing the injury site were removed for immunohistochemistry, histopathological and western blotting analysis. Immunohistochemistry for GFAP, aggrecan, neurocan and NeuN was used to assess the degree of astrocytic glial scar formation and neuron survival. Immunohistochemistry and western blotting analysis for TNF-?, IL-6, IL-1? was used to evaluate the anti-inflammation effect of BBAE. To evaluate its inhibition effect on the astrocytes, we performed the MTT assay and immunohistochemistry for Ki67 in vitro. Results show that the BBAE-treated animals showed significantly better locomotor functional recovery, neuron death and smaller glial scar formation after spinal cord injury in vivo. In addition, BBAE administration could inhibit astrocyte proliferation in vivo and vitro. Therefore, BBAE may be useful as a promising therapeutic agent for SCI. PMID:23001399

Wang, Jun; Ma, Chuan; Rong, Wei; Jing, Hao; Hu, Xing; Liu, Xiaoguang; Jiang, Liang; Wei, Feng; Liu, Zhongjun

2012-12-01

172

Bioavailability of inorganic arsenic from bog ore-containing soil in the dog.  

PubMed Central

In some parts of The Netherlands, bog ore-containing soils predominate, which have natural arsenic levels that exceed, by a factor of 10, existing standards for maximum allowable levels of inorganic arsenic in soil. These standards are based on the assumption that in humans the bioavailability of arsenic from ingested soil is equal to that from an aqueous solution. In view of the regulatory problem that the arsenic levels of these soils present, we questioned the validity of this assumption. To obtain a more realistic estimate, the bioavailability of inorganic arsenic from soil in a suitable animal model was studied. In this report, a study performed in six dogs in a two-way cross-over design is presented. The dogs received orally, in random order, arsenic both as an intravenous solution and as arsenic-containing soil. During a 120-hr period after administration urine was collected in 24-hr fractions. Levels of arsenic were determined using a method of wet digestion, isolation and complexation of arsine, followed by molecule absorption spectrometry. Within 120 hr after intravenous administration, 88 +/- 16% of the dose was excreted renally. After oral administration of arsenic-containing soil, only 7.0 +/- 1.5% was excreted renally. From the urinary excretion data for these two routes of administration, the calculated bioavailability of inorganic arsenic from soil was 8.3 +/- 2.0%. The results from this study demonstrate the need to reconsider the present risk assessment for arsenic in soil. Images Figure 1. Figure 2. PMID:8033848

Groen, K; Vaessen, H A; Kliest, J J; de Boer, J L; van Ooik, T; Timmerman, A; Vlug, R F

1994-01-01

173

[Spatial structure of communities of heterotrophic flagellates from a sphagnum bog].  

PubMed

Spatial distribution pattern of heterotrophic flagellates within a macroscopically homogenous sphagnum parcel of a transitional bog in the southern taiga was studied. Under investigation was horizontal pattern at different scales (1 cm, 10 cm, 1 m, 10 m) and the vertical heterogeneity of the community in the sphagnum quagmire. 105 species and forms of heterotrophic flagellates were revealed. Predominating were euglenids, less abundant are kynetoplastids and cercomonads. The most numerous appeared to be Cryptomonas sp., Heteromita minima, Goniomonas truncata, Protaspis simplex, Bodo designis, B. saltans, Phyllomitus apiculatus, Paraphysomonas sp., Petalomonas minuta. More abundant species were characterized by less patchy distribution than less abundant. At a smaller scale, the community was formed by the species with different degree of patchiness while at larger scales, all the species possess nearly the same distribution pattern. The same number of samples of equal sizes revealed nearly the same species numbers independently of distances between the sample sites, as the samples at each scale differ from each other nearly at the same magnitude. An averaged size of the species aggregations in the community is as large as several centimeters. Such a scale is probably a characteristic size (minimum area) of the community of the sphagnum dwelling heterotrophic flagellates. Rather low environmental heterogeneity within the sphagnum quagmire leads to significant homogeneity of the community at larger scales. Vertical differentiation of the heterotrophic flagellate community within that quagmire appeared to be very unstable with the time. The same species are characterized by different preferences to the depths at different spatial-temporal loci. Specific vertical distributions and community patterns are formed under different local conditions. PMID:19326857

Tikhonenkov, D V; Maze?, Iu A

2009-01-01

174

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

SciTech Connect

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 CO{sub 2}, CH{sub 4}, and Co in response to water table variation were studied under controlled conditions in the Duke University phytotron. Core microcosms thawed to a 20-cm depth over 30 days under a 20 hour photoperiod with a day/night temperature regime of 20/10{degrees}C. After 30 days the water table in 20 microcosms was decreased from the soil surface to -15 cm and maintained at the soil surface in 20 control cores. Outward fluxes of CO{sub 2} (9-16 g m{sup -2}d{sup -1}) and CO (3-4 mg m{sup -2}d{sup -1}) were greatest during early thaw and decreased to near zero for both gases before the water table treatment started. Lower water table tripled CO{sub 2} flux to the atmosphere when compared with control cores. Carbon monoxide was emitted at low rates from high water table cores and consumed by low water table cores. Methane fluxes were low (<1 mg m{sup -2}d{sup -1}) in all cores during thaw. High water table cores increased CH{sub 4} flux to 8-9 mg m{sup -2}d{sup -1} over 70 days and remained high relative to the low water table cores (<0.74 mg m{sup -2}d{sup -1}). Although drying of wetland taiga soils may decrease CH{sub 4} emissions to the atmosphere, the associated increase in CO{sub 2} due to aerobic respiration will likely increase the global warming potential of gas emissions from these soils. 43 refs., 4 figs.

Funk, D.W.; Pullmann, E.R.; Peterson, K.M. [Univ. of Alaska, Anchorage, AK (United States)] [and others] [Univ. of Alaska, Anchorage, AK (United States); and others

1994-09-01

175

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

USGS Publications Warehouse

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.

Granger, Harry Clifford; Warren, C. G.

1979-01-01

176

Chronology of Holocene rock-avalanche deposits based on Schmidt-hammer relative dating and dust stratigraphy in nearby bog deposits, Vora, inner Nordfjord, Norway  

Microsoft Academic Search

A number of large rock avalanches from the northern slope of the 1435 m high mountain of Vora in Breim, inner Nordfjord have been mapped. The avalanche tongues dam the 4 km long Sandalsvatnet, they cover an area of 3 km 2 and the volume exceeds 100 million m3. Age estimates have been obtained by radiocarbon datings of rock dust

Asbjørn Rune Aa; Jan Sjåstad; Eivind Sønstegaard; Lars Harald Blikra

2007-01-01

177

Holocene vegetation and climate change recorded in alpine bog sediments from the Borreguiles de la Virgen, Sierra Nevada, southern Spain  

NASA Astrophysics Data System (ADS)

High-resolution pollen and magnetic susceptibility (MS) analyses have been carried out on a sediment core taken from a high-elevation alpine bog area located in Sierra Nevada, southern Spain. The earliest part of the record, from 8200 to about 7000 cal yr BP, is characterized by the highest abundance of arboreal pollen and Pediastrum, indicating the warmest and wettest conditions in the area at that time. The pollen record shows a progressive aridification since 7000 cal yr BP that occurred in two steps, first shown by a decrease in Pinus, replaced by Poaceae from 7000 to 4600 cal yr BP and then by Cyperaceae, Artemisia and Amaranthaceae from 4600 to 1200 cal yr BP. Pediastrum also decreased progressively and totally disappeared at ca. 3000 yr ago. The progressive aridification is punctuated by periodically enhanced drought at ca. 6500, 5200 and 4000 cal yr BP that coincide in timing and duration with well-known dry events in the Mediterranean and other areas. Since 1200 cal yr BP, several changes are observed in the vegetation that probably indicate the high-impact of humans in the Sierra Nevada, with pasturing leading to nutrient enrichment and eutrophication of the bog, Pinus reforestation and Olea cultivation at lower elevations.

Jiménez-Moreno, Gonzalo; Anderson, R. Scott

2012-01-01

178

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

PubMed

Sphagnum moss was collected from 21 ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca bituminous sands in Alberta (AB). In comparison to contemporary Sphagnum moss from four bogs in rural locations of southern Germany (DE), the AB mosses yielded lower concentrations of Ag, Cd, Ni, Pb, Sb, and Tl, similar concentrations of Mo, but greater concentrations of Ba, Th, and V. Except for V, in comparison to the "cleanest", ancient peat samples ever tested from the northern hemisphere (ca. 6000-9000 years old), the concentrations of each of these metals in the AB mosses are within a factor of 3 of "natural, background" values. The concentrations of "heavy metals" in the mosses, however, are proportional to the concentration of Th (a conservative, lithophile element) and, therefore, contributed to the plants primarily in the form of mineral dust particles. Vanadium, the single most abundant trace metal in bitumen, is the only anomaly: in the AB mosses, V exceeds that of ancient peat by a factor of 6; it is therefore enriched in the mosses, relative to Th, by a factor of 2. In comparison to the surface layer of peat cores collected in recent years from across Canada, from British Columbia to New Brunswick, the Pb concentrations in the mosses from AB are far lower. PMID:25259407

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

2014-11-01

179

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

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

180

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

NASA Astrophysics Data System (ADS)

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.

McKenzie, Jeffrey M.; Voss, Clifford I.; Siegel, Donald I.

2007-04-01

181

Rhodoblastus sphagnicola sp. nov., a novel acidophilic purple non-sulfur bacterium from Sphagnum peat bog.  

PubMed

An isolate of purple non-sulfur bacteria was obtained from an acidic Sphagnum peat bog and designated strain RS(T). The colour of cell suspensions of this bacterium growing in the light under anaerobic conditions is purplish red. Cells of strain RS(T) are rod-shaped, 0.8-1.0 microm wide and 2.0-6.0 microm long, motile by means of polar flagella, reproduce by budding and have a tendency to form rosette-like clusters in older cultures. The cells contain lamellar intracytoplasmic membranes underlying, and parallel to, the cytoplasmic membrane. The photosynthetic pigments are bacteriochlorophyll a and carotenoids; the absorption spectrum of living cells shows maxima at 377, 463, 492, 527, 592, 806 and 867 nm. The cells grow photoheterotrophically under anaerobic or microaerobic conditions with various organic carbon sources or grow photolithoautotrophically with H(2) and CO(2). Strain RS(T) is a moderately acidophilic organism exhibiting growth at pH values between 4.8 and 7.0 (with an optimum at pH 5.2-5.5). The major fatty acids are 16 : 1omega7c and 18 : 1omega7c; the major quinones are Q-10 and Q-9. The DNA G + C content of strain RS(T) is 62.6 mol%. Analysis of the 16S rRNA gene sequence revealed that the novel isolate is most closely related (97.3 % sequence similarity) to the type strain ATCC 25092(T) of the moderately acidophilic purple non-sulfur bacterium Rhodoblastus acidophilus, formerly named Rhodopseudomonas acidophila. However, in contrast to Rbl. acidophilus, strain RS(T) is not capable of aerobic growth in the dark, has no spirilloxanthin among the carotenoids and differs in the pattern of substrate utilization. The value for DNA-DNA hybridization between strain RS(T) and Rbl. acidophilus ATCC 25092(T) is only 22 %. Thus, strain RS(T) represents a novel species of the genus Rhodoblastus, for which the name Rhodoblastus sphagnicola sp. nov. is proposed. Strain RS(T) (=DSM 16996(T) = VKM B-2361(T)) is the type strain. PMID:16738120

Kulichevskaya, Irina S; Guzev, Vladimir S; Gorlenko, Vladimir M; Liesack, Werner; Dedysh, Svetlana N

2006-06-01

182

Forested peat bogs and balance of natural organic matter - questions of use and management in the Ore Mountains (Germany \\/ Czech Republic)  

Microsoft Academic Search

Since the beginning of the 1990's, changes in humic matter quantity and quality of surface waters and drinking water reservoirs, were observed from catchment areas in the Ore Mountains. Humic means natural organic matter (NOM). Forested catchments with high shares of peat bogs show the strongest increase of NOM output. Ditches regulate the water balance of most of the peat

Jörg Scheithauer; Karsten Grunewald; Thomas Kanne

183

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

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

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

1991-01-01

184

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

Microsoft Academic Search

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.

Ann M. Spearing

1972-01-01

185

Temporal variation in depth to water table and hydrochemistry in three raised bogs and their laggs in coastal British Columbia, Canada  

NASA Astrophysics Data System (ADS)

The laggs of three raised bogs in coastal British Columbia were studied in 2010-2012 to determine the temporal variation in depth to water table and hydrochemistry. The lagg is an integral, but rarely studied, part of a raised bog that helps to maintain the water mound in the bog and provides a buffer for runoff from adjacent mineral areas. Depth to water table measurements in 25 piezometers displayed similar annual fluctuations, with the highest water table in winter and the lowest at the end of summer. The smallest fluctuations in depth to water table were recorded closest to the bog centre, and the largest fluctuations in the laggs and adjacent mineral soil sites. Removal of a mature forest stand on one of the study transects resulted in a "watering-up" of the lagg site; the mean water level between August and November increased by 8 cm from 2010 to 2011, and by up to 27 cm during the driest time of the year. pH, pH-corrected electrical conductivity, and Na+ and Mg2+ concentrations varied little during the study period, whereas Ca2+, K+, Cl-, and DOC concentrations and acidity were more variable.

Howie, S. A.; van Meerveld, H. J.

2012-12-01

186

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

Microsoft Academic Search

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

Jeffrey M. McKenzie; Clifford I. Voss; Donald I. Siegel

2007-01-01

187

Carbon dioxide flux and net primary production of a boreal treed bog: responses to warming and water table manipulations  

NASA Astrophysics Data System (ADS)

Mid-latitude treed bogs are significant carbon (C) stocks and are highly sensitive to global climate change. In a dry continental treed bog, we compared three sites; control, recent (1-3 years; experimental) and older drained (10-13 years; drained) with water levels at 38, 74 and 120 cm below the surface, respectively. At each site we measured carbon dioxide (CO2) fluxes and tree root respiration (Rr) (across hummock-hollow microtopography of the forest floor) and net primary production (NPP) of trees during the growing seasons (May to October) of 2011-2013. The carbon (C) balance was calculated by adding net CO2 exchange of the forest floor (NEff-Rr) to the NPP of the trees. From cooler and wetter 2011 to driest and warmest 2013, The control site was a~C sink of 92, 70 and 76 g m-2, experimental site was a C source of 14, 57 and 135 g m-2, and drained site was a progressively smaller source of 26, 23 and 13 g m-2, respectively. Although all microforms at the experimental site had large net CO2 emissions, the longer-term drainage and deeper water level at the drained site resulted in the replacement of mosses with vascular plants (shrubs) at the hummocks and lichens at the hollows leading to the highest CO2 uptake at drained hummocks and significant losses at hollows. The tree NPP was highest at the drained site. We also quantified the impact of climatic warming at all water table treatments by equipping additional plots with open-top chambers (OTCs) that caused a passive warming on average of ∼1 °C and differential air warming of ∼6 °C (at mid-day full sun) across the study years. Warming significantly enhanced the shrub growth and CO2 sink function of the drained hummocks (exceeding the cumulative respiration losses at hollows induced by the lowered water level × warming). There was an interaction of water level with warming across hummocks that resulted in largest net CO2 uptake at warmed drained hummocks. Thus in 2013, the warming treatment enhanced the sink function of control by 13 g m-2, reduced the source function of experimental by 10 g m-2, and significantly enhanced the sink function of the drained site by 73 g m-2. Therefore, drying and warming in continental bogs is expected to initially accelerate C losses via respiration but persistent drought and warming is expected to restore the peatland's original C sink function as a result of transitional shift of vegetation between the microforms and increased NPP of trees over time.

Munir, T. M.; Perkins, M.; Kaing, E.; Strack, M.

2014-09-01

188

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

SciTech Connect

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.

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

1981-01-01

189

Are Bogs Reservoirs for Emerging Disease Vectors? Evaluation of Culicoides Populations in the Hautes Fagnes Nature Reserve (Belgium)  

PubMed Central

Several species of Culicoides (Diptera: Ceratopogonidae) biting midges serve as biological vectors for the bluetongue virus (BTV) and the recently described Schmallenberg virus (SBV) in northern Europe. Since their recent emergence in this part of the continent, these diseases have caused considerable economic losses to the sheep and cattle industries. Much data is now available that describe the distribution, population dynamics, and feeding habits of these insects. However, little is known regarding the presence of Culicoides in unusual habitats such as peaty marshes, nor their potential vector capacity. This study evaluated Culicoides biting midges present in the bogs of a Belgian nature reserve compared to those residing at a nearby cattle farm. Culicoides were trapped in 2011 at four different sites (broadleaved and coniferous forested areas, open environments, and at a scientific station) located in the Hautes Fagnes Nature Reserve (Belgium). An additional light trap was operated on a nearby cattle farm. Very high numbers of biting midges were captured in the marshy area and most of them (70 to 95%) were Culicoides impunctatus, a potential vector of BTV and other pathogens. In addition, fewer numbers of C. obsoletus/C. scoticus species, C. chiopterus, and C. dewulfi were observed in the bogs compared to the farm. The wet environment and oligotrophic nature of the soil were probably responsible for these changes in the respective populations. A total of 297,808 Culicoides midges belonging to 27 species were identified during this study and 3 of these species (C. sphagnumensis, C. clintoni and C. comosioculatus) were described in Belgium for the first time. PMID:23799137

Zimmer, Jean-Yves; Smeets, Francois; Simonon, Gregory; Fagot, Jean; Haubruge, Eric; Francis, Frederic; Losson, Bertrand

2013-01-01

190

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

Microsoft Academic Search

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

David B. Nedwell; Andrea Watson

1995-01-01

191

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

UNDERGRADUATE CC CoSRGE CoSFP UCC COD FCM FCSA BOG CCHE Add New Major/ Program of Study X X X X X X X Change Major/Program of Study X X X Change Name of Existing Major/Program of Study X X X X Change Name of Concentration/ Option; Minor/Interdisciplinary Minor X X X Add/Drop Concentration

Collett Jr., Jeffrey L.

192

Demographic and genetic status of an isolated population of bog turtles ( Glyptemys muhlenbergii ): implications for managing small populations of long-lived animals  

Microsoft Academic Search

In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened\\u000a bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture–recapture data, we estimated adult survival and population growth rate from 1992 to 2007.\\u000a We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult

Shannon E. Pittman; Timothy L. King; Søren Faurby; Michael E. Dorcas

193

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

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

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

2003-01-01

194

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

NASA Astrophysics Data System (ADS)

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.

Beyer, C.; Höper, H.

2014-03-01

195

Dissolved carbon and nitrogen quantity and quality at natural, drained and re-wetted bog sites in Lower Saxony (Germany)  

NASA Astrophysics Data System (ADS)

5 % of Germany's land area is covered with peatlands. Due to the large carbon and nitrogen stocks, changes in peatland hydrology for agricultural use have a huge impact on C and N cycling in the peatland and on the export to the atmosphere and adjacent ecosystems. Nonetheless, only a few studies focussed on the impact of drainage and re-wetting on C and N cycling in German raised bogs. Four study sites in the "Ahlenmoor" near Cuxhaven (Northwestern Germany) were chosen. This bog has a deep, medium to weakly decomposed peat layer. The sites represent a gradient of the groundwater level combined with land use differences (intensive and extensive grassland, natural site, re-wetted peat-cutting area). The mean annual groundwater level decreases from the natural and re-wetted sites (near surface) to the extensive grassland (30 cm below surface) and, finally, the intensive grassland (56 cm). The "Peeper" technique (dialysis sampler) was used to measure soil water chemistry in a high spatial resolution. At each site, three peepers (0-60 cm, 12 chambers each) collected soil water samples via diffusion. Monthly sampling was conducted from February 2012 till November 2012. The soil water solution was analysed for pH, EC, dissolved organic carbon (DOC), dissolved organic nitrogen (DON), NH4+, NO3- and SUVA(280). Samples taken in November 2012 were additionally analysed for dissolved CO2, CH4 and N2O. Average DOC concentrations ranged from 211 to 41 mg/L and decreased in order intensive > extensive grassland > re-wetted = natural site. After 10 years of restoration, the re-wetted and the natural site show similar DOC concentrations. Average SUVA(280) values of 3.7 to 3.3 L/(mg m) were higher at the grassland sites than at the re-wetted and the natural site. This indicates a distinct increase in aromaticity of DOC in grassland sites as a result of more intense humification of the upper peat layer. In contrast to mineral soils, SUVA(280) remained constant with depth at our sites. Total nitrogen decreased in same order as DOC and was mainly composed of DON. NH4+ dominates the inorganic nitrogen fraction. The comparison of peat C/N to DOC/DON ratios indicates that the more degraded upper layer is the main source of carbon and nitrogen in the soil solution. Dissolved inorganic carbon (DIC) was mainly measured as dissolved CO2-C (13.6 mg/L), followed by CH4-C (1.7 mg/L). While CH4-C was present over the whole profile at the re-wetted and the natural site, it was missing in the upper 40 cm of the grassland sites. Instead, dissolved N2O-N was found (19.8 µg/L). Especially in natural bogs with low DOC concentrations, DIC may be a relevant part of the carbon budget. Our results show that the groundwater level in combination with land use has a huge impact on C- and N-quality and quantity between sites and within the peat profile, and that re-wetting may result in a return to "natural" DOC concentration levels and properties.

Frank, Stefan; Tiemeyer, Bärbel; Freibauer, Annette

2013-04-01

196

Geochemical response of a calcareous fen to road salt contamination during snow melt and precipitation events: Kampoosa Bog, Stockbridge, MA  

NASA Astrophysics Data System (ADS)

Kampoosa Bog is the largest and most diverse calcareous lake-basin fen remaining in Massachusetts, and it is one of the state's elite Areas of Critical Environmental Concern (ACEC). The ground water chemistry of the fen has been greatly altered by road salt runoff (NaCl) from the Massachusetts Turnpike, which crosses the northern margin of the wetland complex. Ground water samples collected at different depths within the wetland, measurements of exchangeable Na from an eight-meter core, and hydraulic conductivity measurements suggest that ground water flow and contamination is largely a near- surface phenomenon. Detailed sampling of surface and ground waters during three spring snow melt events and one precipitation event characterizes the geochemical response of the wetland to hydrologic events. Overall, Na:Cl ratios for surface and ground water samples are less than one, and sodium and chloride imbalances suggest that 20-30% of sodium from rock salt is stored on cation exchange sites on organic material. Na:Cl ratios greater than one for fen ground water sampled during Snow Melt 2007 suggest that sodium can be released from cation exchange sites back to ground water under dilute conditions. The total mass of Na and Cl exported from the wetland is greatest under conditions of high discharge. The flux of dissolved salts at the outlet of the fen during Snow Melt 2005 accounts for ~ 24% Na and ~ 32% Cl of rock salt added to the Massachusetts Turnpike during 2004-2005. Estimates of annual fluxes of Na and Cl are on par with the amount of road salt applied, and sodium and chloride concentrations in shallow groundwater have decreased since 2002. The months of March, April and May are the primary months for salt export, accounting for more than half of the annual salt flux in 2005. Concerning the annual net export of sodium and chloride, large rain events may be more important with removing dissolved salts from the fen than snow melt because snow melt also is a time when contamination enters the wetland. The mass of sodium and chloride exported from Kampoosa Bog is consistent with the length of roadway miles within the watershed. Therefore, changes in the amount of salt applied are likely to have significant effects on the long-term concentrations of contamination.

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

2008-12-01

197

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)

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.

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

1994-01-01

198

Reconnaissance of uranium and copper deposits in parts of New Mexico, Colorado, Utah, Idaho, and Wyoming  

USGS Publications Warehouse

Because of the common association of uranium and copper in several of the commercial uranium deposits in the Colorado Plateau Province, a reconnaissance was made of several known deposits of copper disseminated through sandstone to determine whether they might be a source of uranium. In order to obtain more information regarding the relationship between copper, uranium and carbonaceous materials, some of the uraniferious asphaltrite deposits in the Shinarump conglomerate along the west flank of the San Rafael Swell were also investigated briefly. During this reconnaissance 18 deposits were examined in New Mexico, eight in Utah, two in Idaho, and one each in Wyoming and Colorado. No uranium deposits of commercial grade are associated with the copper deposits that were examined. The uraniferous asphaltites in the Shinarump conglomerate of Triassic age on the west flank of the San Rafael Swell, however, are promising from the standpoint of commercial uranium production. Spectrographic analyses of crude oil, asphalt, and bituminous shales show a rather consistent suite of trace metals including vanadium, nickel, copper, cobalt, chromium, lead zinc, and molybdenum. The similarity of the metal assemblage, including uranium of the San Rafael Swell asphaltites, to the metal assemblage in crude oil and other bituminous materials suggests that these metals were concentrated in the asphaltites from petroleum. However, the hypothesis that uranium minerals were already present before the hydrocarbons were introduced and that some sort of replacement or uranium minerals by carbon compounds was effected after the petroleum migrated into the uranium deposit should not be disregarded. The widespread association of uranium with asphaltic material suggests that it also may have been concentrated by some agency connected with the formation of petroleum. The problem of the association of uranium and other trace metals with hydrocarbons should be studied further both in the field and in the laboratory.

Gott, Garland B.; Erickson, Ralph L.

1952-01-01

199

Heatwave 2003: high summer temperature, rather than experimental fertilization, affects vegetation and CO2 exchange in an alpine bog.  

PubMed

Nitrogen and phosphorus were added experimentally in a bog in the southern Alps. It was hypothesized that alleviating nutrient limitation will increase vascular plant cover. As a consequence, more carbon will be fixed through higher rates of net ecosystem CO(2) exchange (NEE). The vascular cover did increase at the expense of Sphagnum mosses. However, such vegetation changes were largely independent of the treatment and were probably triggered by an exceptional heatwave in summer 2003. Contrary to the tested hypothesis, NEE was unaffected by the nutrient treatments but was strongly influenced by temperature and water-table depth. In particular, ecosystem respiration in the hot summer of 2003 increased dramatically, presumably owing to enhanced heterotrophic respiration in an increased oxic peat layer. At the end of the experiment, the Sphagnum cover decreased significantly in the nitrogen-fertilized treatment at hummock microhabitats. In the long term, this will imply a proportionally greater accumulation of vascular litter, more easily decomposable than the recalcitrant Sphagnum litter. As a result, rates of carbon fixation may decrease because of stimulated respiration. PMID:18373651

Gerdol, Renato; Bragazza, Luca; Brancaleoni, Lisa

2008-01-01

200

The structure of the microbial communities in low-moor and high-moor peat bogs of Tomsk oblast  

NASA Astrophysics Data System (ADS)

The number, structure, and physical state of the microbial communities in high-moor and low-moor peat bogs were compared. Distinct differences in these characteristics were revealed. The microbial biomass in the high-moor peat exceeded that in the low-moor peat by 2-9 times. Fungi predominated in the high-moor peat, whereas bacteria were the dominant microorganisms in the low-moor peat. The micromycetal complexes of the high-moor peat were characterized by a high portion of dark-colored representatives; the complexes of the low-moor peat were dominated by fast-growing fungi. The species of the Penicillum genus were dominant in the high-moor peat; the species of Trichoderma were abundant in the low-moor peat. In the former, the bacteria were distinguished as minor components; in the latter, they predominated in the saprotrophic bacterial complex. In the high-moor peat, the microorganisms were represented by bacilli, while, in the low-moor peat, by cytophages, myxobacteria, and actinobacteria. The different physiological states of the bacteria in the studied objects reflecting the duration of the lag phase and the readiness of the metabolic system to consume different substrates were demonstrated for the first time. The relationships between the trophic characteristics of bacterial habitats and the capacity of the bacteria to consume substrates were established.

Dobrovol'skaya, T. G.; Golovchenko, A. V.; Kukharenko, O. S.; Yakushev, A. V.; Semenova, T. A.; Inisheva, L. A.

2012-03-01

201

Determination of the organic carbon content in bog and river waters of the taiga zone based on their optical density  

NASA Astrophysics Data System (ADS)

Based on the data of long-term studies of bog and river waters in the taiga zone of Western Siberia, highly significant linear regression models for the relationships between the organic matter content and optical density of the water were developed. The parameters of the relationships obtained are proposed to be used for the determination of the water-soluble carbon content. The inclusion only of the optical density values into the calculated formulas makes them convenient for practical application. Regression models were developed on the basis of the data on determining the carbon content using the bichromate method, which is widely used in soil and hydrochemical studies. The calculated method forms prerequisites for the operational monitoring of the water-soluble organic substances, since the obtained results can be comparable with the earlier published data on the carbon content determined by the same method. These regression models seem to also be suitable for the determination of the organic carbon in the water extracts of organic soils.

Efremova, T. T.; Sekretenko, O. P.; Efremov, S. P.

2014-08-01

202

Cutaneous deposits.  

PubMed

: The cutaneous deposition disorders are a group of unrelated conditions characterized by the accumulation of either endogenous or exogenous substances within the skin. These cutaneous deposits are substances that are not normal constituents of the skin and are laid down usually in the dermis, but also in the subcutis, in a variety of different circumstances. There are 5 broad categories of cutaneous deposits. The first group includes calcium salts, bone, and cartilage. The second category includes the hyaline deposits that may be seen in the dermis in several metabolic disorders, such as amyloidosis, gout, porphyria, and lipoid proteinosis. The third category includes various pigments, heavy metals, and complex drug pigments. The fourth category, cutaneous implants, includes substances that are inserted into the skin for cosmetic purposes. The fifth category includes miscellaneous substances, such as oxalate crystals and fiberglass. In this article, the authors review the clinicopathologic characteristics of cutaneous deposition diseases, classify the different types of cutaneous deposits, and identify all the histopathologic features that may assist in diagnosing the origin of a cutaneous deposit. PMID:23249837

Molina-Ruiz, Ana M; Cerroni, Lorenzo; Kutzner, Heinz; Requena, Luis

2014-01-01

203

Biochemical processes of oligotrophic peat deposits of Vasyugan Mire  

NASA Astrophysics Data System (ADS)

The problem of peat and mire ecosystems functioning and their rational use is the main problem of biosphere study. This problem also refers to forecasting of biosphere changes results which are global and anthropogenic. According to many scientists' research the portion of mires in earth carbon balance is about 15% of world's stock. The aim of this study is to investigate biochemical processes in oligotrophic deposits in North-eastern part of Vasyugan Mire. The investigations were made on the territory of scientific-research ground (56Ë? 03´ and 56Ë? 57´ NL, 82Ë? 22´ and 82Ë? 42´ EL). It is situated between two rivers Bakchar and Iksa (in outskirts of the village Polynyanka, Bakchar region, Tomsk oblast). Evolution of investigated mire massif began with the domination of eutrophic phytocenosis - Filicinae, then sedge. Later transfer into oligotrophic phase was accompanied by formation of meter high-moor peat deposit. The age of three-meter peat deposit reaches four thousand years. Biochemical processes of carbon cycle cover the whole peat deposit, but the process activity and its direction in different layers are defined by genesis and duration of peat formation. So, the number of cellulose-fermenting aerobes in researched peat deposits ranges from 16.8 to 75.5 million CFU/g, and anaerobic bacteria from 9.6 to 48.6 million CFU/g. The high number of aerobes is characteristic for high water levels, organizing by raised bog peats. Their number decreases along the profile in 1.7 - 2 times. The number of microflora in peat deposit is defined by the position in the landscape profile (different geneses), by the depth, by hydrothermic conditions of years and individual months. But microflora activity shows along all depth of peat deposit. We found the same in the process of studying of micromycete complex structure. There was revealed either active component micromycete complex - mycelium, or inert one - spores in a meter layer of peat deposit. If mushrooms spores are observed in all deposit layers, mycelium of mushrooms deepens into the peat deposit (to 2 meters) within the limits of aerobic (meter) zone and only in particular months of dry years. The existence of seasonal dynamics of eukaryotic cells, and also capability of yeast and other groups of micromycetes for growth, testifies about vital activity of a number of eukaryotic cells at a depth of 2 meters. Researched peat deposits are biochemically active along the whole profile. But they are different in a microflora number of individual physiological groups either in items of the landscape, or in deposit depth. The largest quantity of aerobic cellulose-fermenting microorganisms is marked during dry years. Anaerobic cellulose-fermenting microorganisms dominate during wet years. The quantity of microbe biomass increases in bottom lifts of peat deposits. This fact testifies about viable condition of microbe complex at depth. The formation process of carbon dioxide in peat deposits of Vasyugan Mire actively occurs during dry years and is defined by hydrothermic conditions of a meter layer of peat deposit. The intensity of CO2 isolation for certain correlates with the temperature in horizon of 0 - 50 sm. and with bog waters level. The study of gas composition for the three years showed that the largest concentration of carbon dioxide in peat soils is marked along the whole profile during a dryer year (0.08 - 2.65 millimole/l), increasing other years' level in about 1.5 0 2 times. Emission of carbon dioxide in peat

Inisheva, L. I.; Sergeeva, M. A.

2009-04-01

204

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

NASA Astrophysics Data System (ADS)

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.

Price, Jonathan S.; Whitehead, Grant S.

2004-02-01

205

Elevated Nitrogen Deposition from Alberta Oil Sands Development Stimulates Phosphatase Activity in Dominant Sphagnum Moss Species  

NASA Astrophysics Data System (ADS)

Emissions of NOx associated with Alberta oil sands (AOS) development are leading to locally elevated atmospheric N deposition, in a region where background N deposition has been historically quite low (< 1 kg/ha/yr). This elevated N deposition has the potential to alter the ecosystem structure and function of nutrient-poor boreal peatlands. Nitrogen enrichment may alter soil microbial activity, which could be manifested in changes in extracellular enzyme activities. Since 2011, we have been experimentally adding N as NH4NO3 in simulated precipitation at 0, 5, 10, 15, 20, and 25 kg N ha/yr/ plus no-water controls to a boreal bog and a poor fen (3 replicate plots per treatment). In 2013, acid phosphatase activities in living plant capitulum of Sphagnum angustifolium, Sphagnum fuscum, and Sphagnum magellanicum were quantified in June and July using 4-methyumbelliferylphosphate and fluorescence detection of the enzymatically released methylumbelliferone (MUF). Phosphatase activities did not differ with N treatment for S. angustifolium in the bog (p=0.3409) or the poor fen (p=0.0629), or for S. fuscum in the bog (p=0.1950), averaging 35.0 × 0.7, 61.6 × 1.2, and 41.6 × 0.9 ?mol MUF/g DWT/hr, respectively. For S. fuscum in the poor fen, phosphatase activities differed between N treatments (p=0.0275), ranging 40.6 × 1.1 ?mol MUF/g DWT/hr in the control plots to 73.7 × 2.0 ?mol MUF/g DWT/hr in the 5 kg/ha/yr N treatment plots; increasing N deposition did not result in a gradual change in enzyme activity. On the other hand, S. magellanicum phosphatase activities differed between N treatments (p=0.0189) and showed a pattern of generally increasing activity with increasing N deposition (37.4 × 0.5 ?mol MUF/g DWT/hr in control plots; 97.9 × 4.5 ?mol MUF/g DWT/hr in the 25 kg/ha/yr N treatment plots). The differing phosphatase responses between these dominant Sphagnum species suggest unique differences in nutrient balance and/or microbial activity. Combining the three moss species and weighting by their abundances within each plot (percent cover), phosphatase activities differed between N treatments in the bog (p=0.0388) and the poor fen (p=0.0005), with the latter exhibiting a clear increase in enzyme activity with increasing N deposition, and a doubling of phosphatase activity between the control plots and the 25 kg/kg/yr N deposition treatment. Although the three moss species responded differently, at the plot scale, increasing N deposition stimulated phosphatase activity, suggesting that microbial enzyme activity in peat is sensitive to increasing N deposition from oil sands development, with potential consequences for peatland nutrient cycling.

Kashi, N. N.; Wieder, R.; Vile, M. A.

2013-12-01

206

Alterations in the metabolic fingerprint of Cladonia portentosa in response to atmospheric nitrogen deposition.  

PubMed

Nitrogen availability has profound ecological consequences in nutrient-limited systems. In terrestrial settings these would include the upland heaths, sand dunes and blanket bogs of temperate latitudes. Understanding the physiological consequences of nitrogen enrichment is a first critical step in predicting possible consequences. Results are presented from a metabolic fingerprinting study using Fourier transform-infrared spectroscopy (FTIR) to detect biochemical differences in the lichen Cladonia portentosa collected from 25 sites across mainland Britain varying in their nitrogen input. Partial least-squares regression analysis of the FTIR data demonstrated that changes in broad biochemical classes were consistently correlated with mean annual wet inorganic nitrogen deposition loads. These results demonstrated a direct coupling of a broad range of metabolic processes in C. portentosa to nitrogen deposition. PMID:21569037

Freitag, Sabine; Hogan, Erika J; Crittenden, Peter D; Allison, Gordon G; Thain, Simon C

2011-10-01

207

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

SciTech Connect

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.

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

208

Emission of CO2 from the surface of oligotrophic bogs with due account for their microrelief in the southern taiga of European Russia  

NASA Astrophysics Data System (ADS)

The results of studying the carbon dioxide fluxes from the soil's surface during three years taking into account the microrelief are summarized. More precise estimates were obtained for the annual CO2 emission from the oligotrophic peat bogs differing in vegetation and waterlogging in the southern taiga of European Russia. The maximum differences in the rates of the CO2 emission related to the microrelief elements are characteristic of the treeless ridge-pool complex, where the hollows (without vegetation) emitted CO2 twice less than the flat areas and thrice less than the hummocks. In the forest bogs, the differences related to the microrelief were significantly lower. In the areas with the ridge-pool microrelief, the weighted average (for 3 years) CO2 emission was 436 g C/m2 per year; in the better drained natural dwarf shrub-cotton grass-sphagnum pine forest, 930; and in the drained pine forest, 1292 g C/m2 per year. The share of the CO2 amount emitted in the cold period (November-April) amounted to 10% of its annual flux from the peat soils of the ridge-pool complex and 17 and 24%, respectively, in the natural and drained pine forests.

Glukhova, T. V.; Vompersky, S. E.; Kovalev, A. G.

2013-12-01

209

The Effects of Peatland Plant Functional Types and Altered Hydrology on Porewater Chemistry in a Northern Bog  

NASA Astrophysics Data System (ADS)

Northern wetlands, peatlands in particular, have been shown to store around 30% of the world's soil carbon and thus play a significant role in the carbon cycle of our planet. Carbon accumulation in peatlands is the result of retarded decomposition due to low oxygen availability in these water-logged environments. Changes in our planet's climate cycles are altering peatland hydrology and vegetation communities, resulting in changes in their ability to sequester carbon through increases in peat carbon oxidation and mineralization. To date, the consequences of altered hydrology and changes in vegetation communities, and their interactive effects on carbon storage, are not well understood. We have initiated a research plan that assesses the varying roles that water table variation and vegetation communities have on extracellular enzyme activity and labile carbon availability in porewater from an ombrotrophic bog. We assessed the effects of plant functional group (ericaceous shrubs, sedges, and bryophytes) and water table position on biogeochemical processes. Specifically, we measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), enzyme activity, organic acids, anions and cations, spectral indexes of aromaticity, and phenolic content in addressing our hypotheses of responses to climate change drivers. Research on these components will evaluate the relative importance of biology, water table, and their interactive affects on the porewater quality of peatlands. We hypothesized that oxygen availability will strongly influence decomposition in these systems but that this response will largely be mediated by changes in plant community and the enzymes associated with root exudates and mycorrhizae. To date, our data confirm vegetation and water table related patterns. Acetate and propionate concentrations in the sedge-dominated communities dropped significantly with depth and drainage, relative to the control and ericaceous treatments, which likely reflects changes in redox potential owing to physiological differences in sedges which contain aerenchyma cell, and a reduction in the products of anaerobic metabolism. DOC increased in the lowered water table treatments in all vegetation community types. Enzymatic activities have changed in response to water table level and vegetation community. While we have not detected significant levels of peroxidase enzymes in porewater, initial results indicate that hydrolase enzyme activities were higher in the sedge-dominated communities with a lowered water table. Through this research, we are hoping to advance our knowledge of the drivers behind peatland biogeochemistry and how ombrotrophic peat systems may respond to climate change influences.

Daniels, A.; Kane, E. S.; Lilleskov, E. A.; Kolka, R. K.; Chimner, R. A.; Potvin, L. R.; Romanowicz, K. J.

2012-12-01

210

Holocene climate dynamics in the Eastern Italian Alps: a multi-proxy study from ice and peat bogs  

NASA Astrophysics Data System (ADS)

The Eastern Italian Alps are located near one of the areas in the world with some of the longest records of extreme environmental use by human activity. In this area, paleo-climate studies are hampered by the lack of high-resolution multi-proxy records with adequate chronological control. With this project, we propose to reconstruct Holocene climatic and environmental variations in the Eastern Italian Alps using terrestrial and glaciological archives. We aim to study the characteristics of different climate stages in this sector of the Alps using an ice core drilled on the top of the Ortles glacier (46°30' N, 10°32 E, 3850 m a.s.l.) and ombrotrophic peat bog records from the Dolomites (Danta di Cadore, 46°34' N, 12°33 E, 1400 m a.s.l. and Coltrondo 46°39'28.37''N 12°26'59.17''E, 1800 m a.s.l., Belluno province). The study of global climatic change require a holistic and multi-proxy approach to better understand several complex and often non-linear relationships. In the Italian Alps our study on peat cores represents the first attempt where a multi-proxy approach is applied, and here we report our first results. A 7.0 m peat sequence was extracted in Danta di Cadore. The depth-age scale, based upon independent 14C and 210Pb dates and modeled with the Clam method (Blaauw, 2010), demonstrates that the archive covers more than 13,200 years (cal BP). We determined physical proprieties, Ca and Ti trends, pore water pH, conductivity, and Ca/Mg ratios to identify changes in trophic conditions. The results confirm that the uppermost 400 cm are composed of ombrotrophic peat representing the longest Eastern Alpine ombrotrophic record yet obtained, covering the last 7,000 years. The oldest radiocarbon age (13,200 years cal BP) provides evidence that, during the Bölling-Alleröd interstadial, the upper part of the Piave Glacier was ice-free up to 1400 m a.s.l.. At that time pollen assemblages show that a conifer forest characterized the local vegetation. This forest was then affected by the climatic cooling of the Younger Dryas, which caused an opening of the vegetation. The climatic amelioration occurring at the onset of the Holocene favored the local expansion of warmth-demanding species. X-ray Fluorescence Core Scanner (XRF-CS) analysis was applied for the first time on Eastern Alpine peat sequences. XRF-CS signals were calibrated with ICP-MS, showing very high correlation and demonstrating that the XRF-CS technique provides reliable quantitative data. Results provide information about geochemical processes occurring in the bog. The impact of mining activity was also evaluated. Concentration levels and enrichment factors (EFs) of several trace elements such as Pb, Ag and Cd correspond to the historical data about mining activities in the Cadore region. Lead isotopes ratios were measured to identify natural and anthropogenic sources of Pb emissions. Results show an increase of Pb deriving from fuel combustion over the last decades that gradually overlie the impacts of mining activity. The decreasing 206Pb/207Pb trend reached its minimum value of 1.153 in the 1990s and then increased again. In these years, Italy started to follow EU rules to limit global pollutants in the atmosphere, and finally banned leaded fuels in 2002. Both 206Pb/207Pb ratio and Pb fluxes show a particular event between 1975 and 1980: this behavior is characteristic of the ILE (Isotopic Lead Experiment), a large-scale isotopic tracer experiment which was carried out in the Piedmont region (N-W Italy). This multi-proxy approach that integrates, using new chronological insights, chemical physical and biological features of the core, improves our understanding of Eastern Alpine Holocene climate, helping to delineate biotic and abiotic responses to climate dynamics during the present interglacial. Blaauw, M. 2010. Methods and code for 'classical' age modeling of radiocarbon sequences. Quarternary Geochronology, 5: 512-518.

Poto, Luisa; Gabrieli, Jacopo; Segnana, Michela; Festi, Daniela; Oeggl, Klaus; Barbante, Carlo

2014-05-01

211

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

USGS Publications Warehouse

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.

Saad, David A.

2005-01-01

212

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

NASA Astrophysics Data System (ADS)

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.

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

213

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...

214

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...

215

76 FR 21265 - Interest on Deposits; Deposit Insurance Coverage  

Federal Register 2010, 2011, 2012, 2013

...FEDERAL DEPOSIT INSURANCE CORPORATION 12 CFR Parts 329 and 330 RIN 3064-AD78 Interest on Deposits; Deposit Insurance Coverage AGENCY: Federal Deposit Insurance Corporation (FDIC). ACTION: Notice...

2011-04-15

216

Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modeling analysis  

NASA Astrophysics Data System (ADS)

Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to analyze impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behavior. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to high tolerance of Sphagnum to N deposition in the model. Model performance regarding the 8 year response of GEP and NEE to N was improved by introducing an N content threshold shifting the response of photosynthesis capacity to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub-Sphagnum dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m-2 yr-1, whereas this was not the case when it became graminoid-dominated. The modeling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

Wu, Y.; Blodau, C.; Moore, T. R.; Bubier, J. L.; Juutinen, S.; Larmola, T.

2014-07-01

217

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

PubMed

Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season. PMID:21839679

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

2012-05-01

218

Deposition head for laser  

DOEpatents

A deposition head for use as a part of apparatus for forming articles from materials in particulate form in which the materials are melted by a laser beam and deposited at points along a tool path to form an article of the desired shape and dimensions. The deposition head delivers the laser beam and powder to a deposition zone, which is formed at the tip of the deposition head. A controller comprised of a digital computer directs movement of the deposition zone along the tool path and provides control signals to adjust apparatus functions, such as the speed at which the deposition head moves along the tool path.

Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

1999-01-01

219

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)

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.

Lowe, David J.; Blaauw, Maarten; Hogg, Alan G.; Newnham, Rewi M.

2013-08-01

220

Origin and depositional environment of clastic deposits in the Hilo drill hole, Hawaii  

USGS Publications Warehouse

Volcaniclastic units cored at depths of about 87, 164, 178, 226, and 246 m below sea level and carbonate units located between depths of 27 and 53 m below sea level in the Hilo drill core were found to be deposited at or near sea level. Four of these units are hydroclastic deposits, formed when subaerially erupted Mauna Loa lava flows entered the ocean and fragmented to produce quenched, glassy fragments during hydrovolcanic explosions. Ash units 24 and 26, at 178 m depth, accumulated at sea level in a freshwater bog. They contain pyroxenes crystallized from tholeiitic magma that we infer erupted explosively at the summit of Kilauea volcano. Two carbon-rich layers from these ashes have a weighted average radiocarbon age of 38.6 ?? 0.9 ka; the ashes probably correlate with the oldest and thickest part of the Pahala ash. Ash unit 44, at the transition from Mauna Kea to Mauna Loa lava flows, was probably nearly 3.2 m thick and is inferred to be equivalent to the lower thick part of the composite Homelani ash mapped in Hilo and on the flanks of Mauna Kea. The age of this part of Homelani ash is between 128 ?? 33 and 200 ?? 10 ka; it may have erupted subglacially during the Pohakuloa glacial maxima on Mauna Kea. Beach sand units 12 and 22 were derived from nearby Mauna Loa and Mauna Kea lava flows. The middle of beach sand unit 38 was derived mainly from lava erupted near the distal end of the subaerial east rift zone of Kilauea volcano; these sands were transported about 33 km northwest to Hilo Bay by prevailing longshore currents. Combined age, depth, and sea level markers in the core allow us to determine that lava flow recurrence intervals averaged one flow every 4 kyr during the past 86 kyr and one flow every 16 kyr between 86 and 200 ka at the drill site and that major explosive eruptions that deposit thick ash in Hilo have occurred only twice in the last 400 kyr. These recurrence intervals support the moderate lava flow hazard zonation (zone 3) for coastal Hilo previously determined from surficial mapping.

Beeson, M.H.; Clague, D.A.; Lockwood, J.P.

1996-01-01

221

Holocene hydro-climatic change and effects on carbon accumulation inferred from a peat bog in the Attawapiskat River watershed, Hudson Bay Lowlands, Canada  

NASA Astrophysics Data System (ADS)

Multiple proxies from a 319-cm peat core collected from the Hudson Bay Lowlands, northern Ontario, Canada were analyzed to determine how carbon accumulation has varied as a function of paleohydrology and paleoclimate. Testate amoeba assemblages, analysis of peat composition and humification, and a pollen record from a nearby lake suggest that isostatic rebound and climate may have influenced peatland growth and carbon dynamics over the past 6700 cal yr BP. Long-term apparent rates of carbon accumulation ranged between 8.1 and 36.7 g C m- 2 yr- 1 (average = 18.9 g C m- 2 yr- 1). The highest carbon accumulation estimates were recorded prior to 5400 cal yr BP when a fen existed at this site, however following the fen-to-bog transition carbon accumulation stabilized. Carbon accumulation remained relatively constant through the Neoglacial period after 2400 cal yr BP when pollen-based paleoclimate reconstructions from a nearby lake (McAndrews et al., 1982) and reconstructions of the depth to the water table derived from testate amoeba data suggest a wetter climate. More carbon accumulated per unit time between 1000 and 600 cal yr BP, coinciding in part with the Medieval Climate Anomaly.

Bunbury, Joan; Finkelstein, Sarah A.; Bollmann, Jörg

2012-09-01

222

Evaluations of the TiO2/simulated solar UV degradations of XAD fractions of natural organic matter from a bog lake using size-exclusion chromatography.  

PubMed

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

Valencia, Sergio; Marín, Juan M; Restrepo, Gloria; Frimmel, Fritz H

2013-09-15

223

How much does fluvial dissolved organic carbon export from blanket bogs vary at the regional scale? An example from the Pennine region of Yorkshire, UK  

NASA Astrophysics Data System (ADS)

Often only one or a very small number of stream sampling points are used to infer wider regional export of fluvial carbon from peatlands. However, we suggest that the amount of fluvial carbon being exported varies enormously within regions even when blanket peat is the dominant land cover type. Here we present results from an extensive and comprehensive monitoring project covering blanket peat dominated catchments across the Pennine region of the UK using data from 2006 onwards. Up to the start of January 2014 the dataset contained dissolved organic carbon (DOC) data for approximately 11500 stream water samples (both routine spot samples and storm event samples). The majority of these DOC measurements also have associated UV-Vis absorbance data allowing an insight into the composition of the DOC present, specifically the dominance of humic versus fulvic acids and the degree of aromaticity (SUVA254). Additional data to support interpretation of the regional variability of DOC includes particulate organic carbon, discharge, pH, conductivity and turbidity, water table depth, soil water chemistry and meteorological data. We provide an unparalleled insight into the spatial and temporal variability of DOC in a region of blanket bogs showing how catchment attributes influence fluvial DOC, how there are hotspots of DOC production and how high flow events regulating DOC export and its composition.

Grayson, Richard; Blundell, Antony; Holden, Joseph

2014-05-01

224

Instrument Series: Deposition and Microfabrication Sputter Deposition  

E-print Network

chemical and biological sensors Energy sources ­ development of thin film materials systems for research-situ RHEED 35 kV electron source Magnetic shielding � Manufacturer: Denton Vacuum LLC #12;Scientific deposition, electron beam deposition, and in-situ reflection high-energy electron diffraction (RHEED

225

Cascadia Tsunami Deposit Database  

USGS Publications Warehouse

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.

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

2003-01-01

226

Directed vapor deposition  

Microsoft Academic Search

This dissertation describes the invention, design, construction, experimental evaluation and modeling of a new physical vapor deposition technique (U.S. Patent #5,534,314) for high rate, efficient deposition of refractory elements, alloys, and compounds onto flat or curved surfaces. The new Directed Vapor Deposition (DVD) technique examined in this dissertation was distinct from previous physical vapor deposition techniques because it used low

James Frederick Groves

1998-01-01

227

Late-Holocene reconstruction of methane fluxes for the last 3000 years based on testate amoebae assemblages: application to a Canadian boreal peat bog.  

NASA Astrophysics Data System (ADS)

Boreal peatlands cover approximately 350 Mha from which about 50 % is found in North America. These ecosystems are substantial carbon sinks and constitute one of the most important natural source of methane (CH4) to the atmosphere. Annual release of CH4 to the atmosphere has been estimated to range between 20 and 50 Tg yr-1. A strong relationship between water table depth (WTD), plant community and CH4 fluxes is well documented, fluxes being more important as the WTD is closer to the peatland surface. Given their sensibility to peatland surface moisture changes, testate amoebae and plant macrofossils assemblages constitute valuable paleohydrological proxy indicators from which robust WTD reconstruction can be obtained. When coupled to modern CH4 fluxes, WTD fluctuation can potentially yield to holocene CH4 estimates. Based on these assumptions, late-holocene CH4 fluxes from boreal peat bog in the Eastmain-1 region (James Bay, Québec, Canada) were reconstructed. Modern CH4 fluxes were measured using static chambers over different vegetation types following a hydrologic gradient between 2005 and 2006 growing seasons. Two 1m-long peat cores were sampled at 2-cm intervals for macrofossil and testate amoebae analyses, and transfer functions were applied to the latter assemblages in order to estimate past WTD changes. Peat chronologies were controlled by AMS radiocarbon dates and 210Pb dates. Based on modern CH4 emissions, past fluxes were derived paleohydrological reconstruction and transfer to CH4 values throughout the Late-Holocene period. This research highlights the need for a better understanding of the role played by past CH4 emissions from peatlands in atmospheric CH4 concentration.

Pelletier, L.; Loisel, J.; Garneau, M.

2007-12-01

228

Geochronology and Fluid-Rock Interaction Associated with the Nopal I Uranium Deposit, Pena Blanca, Mexico  

SciTech Connect

The Nopal I uranium (U) deposit, Pena Blanca District, Mexico, largely consists of secondary U{sup 6+} minerals, which occur within a breccia pipe mainly hosted by the 44 Ma Nopal and Colorados volcanic formations. These two units overly the Pozos conglomerate formation and Cretaceous limestone. Three new vertical diamond drill holes (DDHs) were recently drilled at Nopal I. DDH-PB1 with continuous core was drilled through the Nopal I deposit and two additional DDHs were drilled {approx}50 m on either side of the cored hole. These DDHs terminate 20 m below the current water table, thus allowing the detection of possible gradients in radionuclide contents resulting from transport from the overlying uranium deposit. Primary uraninite within the main ore body is rare and fine-grained ({approx}50 micrometers), thus making geochronology of the Nopal I deposit very difficult. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few {micro}m. Preliminary U-Pb results show that uraninite from the main ore body gives an age of 32 {+-} 8 Ma, whereas uraninite from the uraniferous Pozos conglomerate that lies nearly 100 m below the main ore body and 25 meters above the water table, gives a U-Pb age that is <1 Ma. Oxygen isotopic analyses show that uraninite from the ore body has a {delta}{sup 18}O = -10.8{per_thousand}, whereas the uraninite within the Pozos conglomerate has a {delta}{sup 18}O = +1.5{per_thousand}. If it is assumed that both uraninites precipitated from meteoric water ({delta}{sup 18}O = -7{per_thousand}), then calculated precipitation temperatures are 55 C for the uraninite from the ore body and 20 C for uraninite hosted by the Pozos conglomerate. These temperatures are consistent with previous studies that calculated precipitation temperatures for clay minerals associated with uraninite.

M. Fayek; P. Goodell; M. Ren; A. Simmons

2005-07-11

229

A late Holocene record of trace metal deposition in lake sediments near Quelccaya Ice Cap, Peru  

NASA Astrophysics Data System (ADS)

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.

Beal, S. A.; Kelly, M. A.; Jackson, B. P.; Osterberg, E. C.; Stroup, J. S.; Baker, R. A.

2010-12-01

230

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

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.

Leventhal, Joel S.

1979-01-01

231

High soil solution carbon und nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 yr of rewetting  

NASA Astrophysics Data System (ADS)

Artificial drainage of peatlands causes dramatic changes in the release of greenhouse gases and in the export of dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting anthropogenically altered 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 yr and 4 month, respectively. The peeper technique was used to receive a high vertical sampling resolution. Within one Atlantic bog complex a near natural site, two drained grasslands sites with different mean water table positions, and a former peat cutting area rewetted 10 yr ago were chosen. Our results clearly indicate that drainage increased the concentration of dissolved organic carbon (DOC), ammonia, nitrate and dissolved organic nitrogen (DON) compared to the near natural site. Drainage depth further determined the release and therefore the concentration level of DOC and N species, but the biochemical cycling and therefore dissolved organic matter (DOM) quality and N species composition were unaffected. Thus, especially deep drainage can cause high DOC losses. In general, DOM at drained sites was enriched in aromatic moieties as indicated by SUVA280 and showed a higher degradation status (lower DOC to DON ratio) compared to the near natural site. At the drained sites, equal C to N ratios of uppermost peat layer and DOC to DON ratio of DOM in soil solution suggest that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOC to DON ratios and SUVA280 values with depth furthermore indicated that DOM moving downwards through the drained sites remained largely unchanged. DON and ammonia contributed most to the total dissolved nitrogen (TN). The subsoil concentrations of nitrate were negligible due to strong decline in nitrate around mean water table depth. Methane production during the winter months at the drained sites moved downwards to areas which were mostly water saturated over the whole year (>40 cm). Above these depths, the recovery of the water table in winter months led to the production of nitrous oxide around mean water table depth at drained sites. 10 yr after rewetting, the DOM quality (DOC to DON ratio and SUVA280) and quantity were comparable to the near natural site, indicating the re-establishment of mostly pristine biochemical processes under continuously water logged conditions. The only differences occur in elevated dissolved methane and ammonia concentrations reflecting 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.

Frank, S.; Tiemeyer, B.; Gelbrecht, J.; Freibauer, A.

2013-10-01

232

Small scale soil carbon and moisture gradients in a drained peat bog grassland and their influence on CO2, CH4 and N2O fluxes  

NASA Astrophysics Data System (ADS)

Due to the UNFCCC report requirements of each country on the emissions of greenhouse gases from key sources the joint research project "Organic Soils" was established in Germany. The project's objective is to improve the data set on greenhousegas emissions from organic soils in Germany. Within 12 German Project Catchments emissions from different types of organic soils, e.g. under different land uses and hydrological conditions, are measured. At the location "Großes Moor" near Gifhorn (Lower Saxony) the effects of small-scale soil organic carbon and groundwater level gradients on the GHG fluxes (CO2, CH4 and N2O) are quantified. The study area is located within a former peat bog altered by drainage and peat cutting, which is currently grassland under extensive agricultural use. The focus of the study is on the acquisition of CO2, CH4 and N2O fluxes on six sites via manual closed chambers. In order to calculate the annual CO2 exchange rate, values are interpolated on a 0.5 hour scale between measurement campaigns. In combination with continually logged meteorological parameters, such as the photosynthetic active radiation as well as air and soil temperatures, we calculate the daily CO2 ecosystem exchange of the different sites. During the 2011 campaign, CO2 was determined as the most important greenhouse gas. The groundwater table was the dominant variable influencing gas emissions. Another important factor was the vegetation composition. In detail, highest CO2 emissions occurred with a water table of 40-50 cm below ground level, temperatures above 10°C and low plant biomass amounts. Due to the more complex formation of N2O by a number of processes, each being promoted by different soil conditions, the measurement of N2O fluxes in the field was complemented by a laboratory experiment. In this, the use of stable isotope tracer techniques enabled us to quantify the contribution of single biochemical pathways to the overall formation of N2O under controlled conditions. This together with the prediction of the systems CO2 exchange, gives valuable information on how degraded peatlands can be restored best or at least be cultivated in a way to achieve climate neutral conditions. Thus, our study improves the prediction, how peatland soils will react to changes of soil and climate conditions with respect to their greenhouse gas emissions.

Leiber-Sauheitl, K.; Fuß, R.; Freibauer, A.

2012-04-01

233

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

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

Pankratov, Timofey A; Dedysh, Svetlana N

2010-12-01

234

MAPLE deposition of nanomaterials  

NASA Astrophysics Data System (ADS)

The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

Caricato, A. P.; Arima, V.; Catalano, M.; Cesaria, M.; Cozzoli, P. D.; Martino, M.; Taurino, A.; Rella, R.; Scarfiello, R.; Tunno, T.; Zacheo, A.

2014-05-01

235

Biomimetic thin film deposition  

SciTech Connect

Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

1995-09-01

236

78 FR 11604 - Deposit Insurance Regulations; Definition of Insured Deposit  

Federal Register 2010, 2011, 2012, 2013

...of this proposed rule is to preserve confidence in the FDIC deposit insurance system...Great Depression, to restore public confidence in the banking system, and to safeguard...payment of deposit insurance preserves confidence in the deposit insurance...

2013-02-19

237

System for depositing thin films  

NASA Technical Reports Server (NTRS)

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.

Tashbar, P. W. (inventor)

1974-01-01

238

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 ...

239

Deposition Overview - Part I  

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 devicesâÂÂ. The lecture runs for 12:53 seconds and covers the basics of desposition, as well as spin-in deposition and thermal oxidation. More information on desposition can be found on the SCME website. 

2014-08-01

240

Peat deposits in Panama: Their potential for use in energy applications  

SciTech Connect

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.

Ramirez, A.; Thayer, G.; Cohen, A.D.; Allen, A.

1986-12-01

241

films deposited by chemical vapour deposition  

NASA Astrophysics Data System (ADS)

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.

Asafa, T. B.; Witvrouw, A.; Morcos, B. S.; Vanstreels, K.; Said, S. A. M.

2014-08-01

242

Vacuum arc deposition devices  

SciTech Connect

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.

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

243

Atmospheric N deposition and feedbacks on net ecosystem CO2 exchange at a semi-natural peatland site  

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

244

Age models for peat deposits on the basis of coupled lead-210 and radiocarbon data.  

NASA Astrophysics Data System (ADS)

The study presents three examples of age-model construction based on the results of 210Pb and 14C dating methods applied to peat deposits. The three sites are ombrotrophic peat bogs: the Misten (Belgium), Slowinskie Bloto (N Poland) and Puscizna Mala (S Poland). All sites have been subjected to multiproxy studies aimed at reconstructing paleoenvironment and human activity, covering the last 1500, 1300 and 1800 years, respectively (De Vleeschouwer et al. 2009A, 2009B, in prep., Fialkiewicz-Koziel, ongoing PhD). A detailed comparison between 210Pb and post-bomb 14C results in the Misten bog has also been carried out by Piotrowska et al. (2009). In all cores, the 210Pb activity was calculated using 210Po and 208Po activities after acid-extraction from bulk samples, subsequent deposition on silver discs and measurements by alpha spectrometry. Unsupported 210Pb was detected until 35cm in Slowinskie Bloto, 15cm in the Misten and 19cm in Puscizna Mala. Constant Rate of Supply (CRS) model was then applied to compute ages of each 1-cm core interval. For the Misten and Slowinskie Bloto, radiocarbon measurements were performed on selected aboveground plant macrofossils, mainly Sphagnum spp. or Calluna vulgaris, Erica tetralix, and Andromeda polyfolia. Radiocarbon ages were determined using accelerator mass spectrometry (AMS) after acid-alkali-acid wash, combustion, purification of carbon dioxide and graphitisation. For Puscizna Mala bulk samples were dated after chemical preparation of benzene for liquid scintillation counting (LSC) or CO2 for gas proportional counting (GPC). Radiocarbon calibration was undertaken using the Intcal04 calibration curve and OxCal 4 software. As a priori information the 210Pb-derived ages were used in a P_Sequence model (Bronk Ramsey, 2008). A number of dates characterized by low agreement with stratigraphical order had to be considered as outliers and rejected from the final age model. For building a continuous age models a non-linear approach called generalized additive model (GAM) was used, as described by Heegaard et al. (2005). The calculations were performed within each period on the middle-point of the 95.4 % range of calibrated age, while an uncertainty equal to half of this range was assumed. The results of 210Pb dating are described by Gaussian distribution and in their case 1-sigma range was used. The resulting age-depth relationships provide a mean age and an age range for each 1-cm thick slice of peat, and allows for calculation of sedimentation rates. This study highlights some important issues connected with radiocarbon dating of peat sequences. Commonly known problems are wide ranges of calibrated ages caused by wiggles in calibration curve for the period just beyond the range of precise 210Pb dates, which can undoubtedly be solved by 14C-dating more samples from thinner slices. It also emphasizes the great potential of Bayesian analysis applied in radiocarbon calibration. The high suitability of coupled 210Pb-14C dating applied to dating of peat deposits was also confirmed. Bronk Ramsey C., 2008. Deposition Models for Chronological Records. Quaternary Science Reviews 27: 42-60. De Vleeschouwer F., Piotrowska N., Sikorski J., Pawlyta J., Cheburkin A., Le Roux G., Lamentowicz M., Fagel N., Mauquoy D., 2009A. Multiproxy evidences of Little Ice Age palaeoenvironmental changes in a peat bog from northern Poland. The Holocene 19,4: 625-637. De Vleeschouwer F., Fagel N., Cheburkin A., Pazdur A., Sikorski J., Mattielli N., Renson V., Fialkiewicz B., Piotrowska N., Le Roux G., 2009B. Anthropogenic impacts in North Poland over the last 1300 years and possible influence of climate on human activities. Science of the Total Environment 407: 5674-5684. De Vleeschouwer F., Luthers C., Court-Picon M., Mauquoy D., Wastiaux C., Le Roux G., Moschen R., Pawlyta J., Pazdur A., Sikorski J., Piotrowska N. In preparation. Multiproxy paleoenvironmental study in the Misten bog (East Belgium) during the last millenium. To be submitted in Quaternary International in June 2010. De Vleeschouwer F., Fagel N. Sikorsk

Piotrowska, Natalia; de Vleeschouwer, François; Sikorski, Jaros?aw; Sensu?a, Barbara; Michczy?ski, Adam; Fia?kiewicz-Kozie?, Barbara; Palowski, Bernard

2010-05-01

245

Mineral deposit density; an update  

USGS Publications Warehouse

A robust method to estimate the number of undiscovered deposits is a form of mineral deposit model wherein numbers of deposits per unit area from well-explored regions are counted and the resulting frequency distribution is used either directly for an estimate or indirectly as a guideline in some other method. The 27 mineral deposit density estimates reported here for 13 different deposit types represent a start at compiling the estimates necessary to guide assessments.

Singer, Donald A.; Menzie, W. David; Sutphin, David M.; Mosier, Dan L.; Bliss, James D.; contributions to global mineral resource assessment research edited by Schulz, Klaus J.

2001-01-01

246

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

SciTech Connect

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.

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

247

MEASUREMENTS OF DRY DEPOSITION VELOCITY MODEL EVALUATION  

EPA Science Inventory

The U.S. Environmental Protection Agency's (EPA) nationwide network to Deposition Network dry deposition of gases and particles, the National Dry Deposition Network (NDDN), measures not deposition, but concentration of pollutants and meteorological relevant to deposition processe...

248

Testing the potential of bacterial branched tetraether membrane lipids as temperature proxy in peat and immature coal deposits  

NASA Astrophysics Data System (ADS)

Branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids occur ubiquitously in peat and soil. In soil, the degree of methylation and cyclisation of branched tetraethers (MBT index and CBT ratio, respectively) has shown to relate to both soil pH and annual mean air temperature (MAT). Using this relation, past annual MATs can be reconstructed by analysing brGDGTs in marine sediment records near large river outflows. More recently, the potential of this MBT/CBT proxy is also being explored in lakes. Despite being more abundant in peat than soils, however, the utility of the proxy has not yet been fully explored in peat records. Present day peat records generally extent back to the early Holocene, but if the MBT/CBT proxy were shown to be applicable in peat deposits, there is also potential to apply it to immature coal deposits like lignites, which could provide valuable snapshots of continental climate back to the early Cenozoic. Here results are presented of analyses of different peats in south eastern Canada, showing that the pH of peat along a nutrient gradient is rather well reflected by the CBT. Annual MAT reconstructions based on the MBT/CBT soil calibration, however, tend to overestimate measured MAT. This is also the case for peat analysed from the surface of Etang de la Gruère peat bog in the Swiss Jura Mountains. Along the 6m depth profile of this bog (~13ka), CBT-reconstructed pH is compared with in-situ measured pore water pH showing that the brGDGT composition does not reflect present-day in-situ conditions. Instead, it reflects a stratigraphic boundary between Carex and Sphagnum dominated peat at 4 m depth that is not present in the pore water profile, testifying to a 'fossil' nature of the brGDGTs down the peat bog. Analyses of three immature coals of the Argonne Premium Coal Series reveal that branched GDGTs are present in the most immature coal, the Beulah Zap lignite (Ro = 0.25%), and only just above detection limit in the Wyodak Anderson coal (Ro = 0.32%), both of about the same age (Late Palaeocene). In the more mature Illinois #6 coal (Ro = 0.46%), brGDGTs are completely absent. In the Denver Basin, a comparison is made between outcrop and drilled core samples of Palaeocene lignites. BrGDGTs are preserved in the core samples, although in low quantities compared to peat. Outcrop samples are clearly overprinted by modern soil derived brGDGTs, despite digging a meters deep trench, which shows the need to obtain fresh non-weathered samples by coring. Reconstructed annual MAT for both the Beulah Zap and the Denver Basin lignites are several degrees higher than estimates based on leaf margin and oxygen isotope analyses from the same sites. Both reconstructions do testify, nevertheless, to the warm continental conditions during the early Cenozoic of the central U.S.A.. Although further validation is required, potentially in the form of a specific peat calibration, these results do show potential for application of the MBT/CBT temperature proxy in peat and lignite deposits.

Weijers, J. W. H.; Steinmann, P.; Hopmans, E. C.; Basiliko, N.; Finkelstein, S. A.; Johnson, K. R.; Schouten, S.; Sinninghe Damsté, J. S.

2012-04-01

249

Laser powder deposition  

Microsoft Academic Search

Purpose – The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional items from a wide range of common engineering materials, such as aluminum alloys, steels, titanium alloys, nickel superalloys and refractory materials. Design\\/methodology\\/approach – The main R&D efforts and the

Lino Costa; Rui Vilar

2009-01-01

250

MODELING DEPOSITION OF INHALED PARTICLES  

EPA Science Inventory

Modeling Deposition of Inhaled Particles: ABSTRACT The mathematical modeling of the deposition and distribution of inhaled aerosols within human lungs is an invaluable tool in predicting both the health risks associated with inhaled environmental aerosols and the therapeut...

251

Acid Deposition Sampling  

NSDL National Science Digital Library

This learning activity from the Advanced Technology Environmental and Energy Center (ATEEC) provides students with the opportunity to use analytical meters and instruments and perform acid deposition sampling. Students will collect samples from various sources over a period of time, then measure pH and develop graphs or charts. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Willey, Babe

2011-02-17

252

Molybdenum in marine deposits  

Microsoft Academic Search

The distribution and rates of accumulation of Mo in marine deposits have been determined and compared with the same parameters for U and Mn. High concentrations of Mo are associated both with oxidizing environments represented by the presence of ferro-manganese oxide-rich sediments (where Mo\\/U ~- 3) and with reducing environments (where Mo\\/U is about unity). The supply of Mo by

Kathe K. Bertine; Karl K. Turekian

1973-01-01

253

Electrophoretic deposition of biomaterials  

PubMed Central

Electrophoretic deposition (EPD) is attracting increasing attention as an effective technique for the processing of biomaterials, specifically bioactive coatings and biomedical nanostructures. The well-known advantages of EPD for the production of a wide range of microstructures and nanostructures as well as unique and complex material combinations are being exploited, starting from well-dispersed suspensions of biomaterials in particulate form (microsized and nanoscale particles, nanotubes, nanoplatelets). EPD of biological entities such as enzymes, bacteria and cells is also being investigated. The review presents a comprehensive summary and discussion of relevant recent work on EPD describing the specific application of the technique in the processing of several biomaterials, focusing on (i) conventional bioactive (inorganic) coatings, e.g. hydroxyapatite or bioactive glass coatings on orthopaedic implants, and (ii) biomedical nanostructures, including biopolymer–ceramic nanocomposites, carbon nanotube coatings, tissue engineering scaffolds, deposition of proteins and other biological entities for sensors and advanced functional coatings. It is the intention to inform the reader on how EPD has become an important tool in advanced biomaterials processing, as a convenient alternative to conventional methods, and to present the potential of the technique to manipulate and control the deposition of a range of nanomaterials of interest in the biomedical and biotechnology fields. PMID:20504802

Boccaccini, A. R.; Keim, S.; Ma, R.; Li, Y.; Zhitomirsky, I.

2010-01-01

254

Pulse plating of nickel deposits  

SciTech Connect

Pulse plated and conventional nickel deposits have been compared for differences in morphology, mechanical properties, and microstructure. The deposits were obtained from nickel sulfamate, nickel chloride, and Watts nickel plating solutions. No significant differences were found in the direct and pulse current deposits from the sulfamate and chloride solutions; however, significant differences in microstructure, yield strength, and microhardness were observed in deposits from the Watts nickel solution.

Stimetz, C.J.; Stevenson, M.F.

1980-02-01

255

Intracranial calcified deposits in neurofibromatosis.  

PubMed Central

Three patients with the central type of neurofibromatosis, who on CT showed multiple subependymal calcified deposits, are presented. The literature on intracranial non-tumourous calcifications in neurofibromatosis is briefly reviewed. On the basis of our findings and the literature, it is proposed that such intracranial calcified deposits may be part of the neurofibromatosis syndrome and are caused by calcium deposits in glial proliferations, analogous to the calcified deposits seen in tuberous sclerosis. Images PMID:3098924

Arts, W F; Van Dongen, K J

1986-01-01

256

Liquefaction in Deposits of River  

USGS Multimedia Gallery

Liquefaction in recent deposits of the Pajaro River formed sand volcanoes along a fissure 6-7 m (19.7-23 ft) long. Variation in grain size and partial erosion of the conical deposits of sand show that venting of the slurry of sand and water was a complex series of depositional and erosional events t...

2009-01-26

257

Determination of (239)Pu, (240)Pu, (241)Pu and (242)Pu at femtogram and attogram levels - evidence for the migration of fallout plutonium in an ombrotrophic peat bog profile.  

PubMed

The isotopic composition of plutonium ((239)Pu, (240)Pu, (241)Pu and (242)Pu) was investigated in a ?0.5 m long peat core from an ombrotrophic bog (Black Forest, Germany) using clean room procedures and accelerator mass spectrometry (AMS). This sophisticated analytical approach was ultimately needed to detect reliably the Pu concentrations present in the peat samples at femtogram (fg) and attogram (ag) levels. The mean (240)Pu/(239)Pu isotopic ratio of 0.19 ± 0.02 (N = 32) in the peat layers, representing approximately the last 80 years, was in good agreement with the accepted value of 0.18 for the global fallout in the Northern Hemisphere. This finding is largely supported by the corresponding and rather constant (241)Pu/(239)Pu (0.0012 ± 0.0005) and (242)Pu/(239)Pu (0.004 ± 0.001) ratios. Since the Pu isotopic composition characteristic of the global fallout was also identified in peat samples pre-dating the period of atmospheric atom bomb testing (AD 1956-AD 1980), migration of Pu within the peat profile is clearly indicated. These results highlight, for the first time, the mobility of Pu in a peat bog with implications for the migration of Pu in other acidic, organic rich environments such as forest soils and other wetland types. These findings constitute a direct observation of the behaviour of Pu at fg and ag levels in the environment. The AMS measurements of Pu concentrations (referring to a corresponding activity of (240+239)Pu from 0.07 mBq g(-1) to 5 mBq g(-1)) essentially confirm our a priori estimates based on existing (241)Am and (137)Cs data in the investigated peat core and agree well with the global fallout levels from the literature. Exclusively employing the Pu isotope ratios established for the peat samples, the date of the Pu irradiation (AD 1956, correctable to AD 1964) was calculated and subsequently compared to the (210)Pb age of the peat layers; this comparison provided an additional hint that global fallout derived Pu is not fixed in the peat column, but has migrated downwards along the peat profile to layers preceding the nuclear age. PMID:23478668

Quinto, Francesca; Hrnecek, Erich; Krachler, Michael; Shotyk, William; Steier, Peter; Winkler, Stephan R

2013-04-01

258

Coffee ring deposition in bands  

NASA Astrophysics Data System (ADS)

Microscopic particles suspended in a liquid are transported and deposited at a contact line, as the contact line recedes due to evaporation. A particle layer of uniform thickness is deposited if the particle concentration is above a threshold; below this threshold the deposit forms periodic bands oriented parallel to the contact line. We present a model for the formation of these bands based on evaporation leading to the breakup of the thin liquid film near the contact line. The threshold results from a competition between evaporation speed and deposition speed. Using this model, we predict the thickness and length of the bands, making the control of patterned deposition possible.

Mandre, Shreyas; Wu, Ning; Aizenberg, Joanna; Mahadevan, Lakshminarayanan

2010-11-01

259

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-10-17

260

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-06-27

261

433 Eros Ponded Deposits  

NASA Astrophysics Data System (ADS)

In certain regions of Eros flat deposits with surfaces perpendicular to the local gravity gradient infill bottoms of depressions. Such morphology is consistent with emplacement with no shear strength, allowing material to "pond" to an equipotential surface. However, ponded deposits currently support steep-walled grooves, impact craters, and superposed blocks, showing that subsequent to emplacement some compaction or cohesion has occurred to create non-zero shear strength. Many of the ponds are relatively blue (high 550/760 nm reflectance ratio ) and have a deeper infrared band (low 950/760 nm ratio), consistent with lesser alteration from the space environment. Such alteration by micrometeorite impacts produces relatively large aggregates of glass and crystalline material. Of 255 ponds greater than or equal to 30 m diameter mapped on the whole asteroid, 91 percent are located within 30 degrees of the equator. Zones asymmetrically around the long ends of the asteroid also have distinctively more and larger ponded deposits. Regions of pond occurrence coincide with areas having low gravity and spending a large fraction of Eros's orbital period near the terminator (due to Eros's 88 degrees obliquity). The long terminator exposure favors creation of photoelectric charge differentials between illuminated and shadowed terrain, capable of lifting and redistributing tens-of-microns size particles. We hypothesize that the ponds formed by electrostatic sedimentation processes that preferentially concentrated the finest, crystalline component of the regolith. This is consistent with the observed color properties: for mafic minerals, as grain size decreases, color becomes redder at visible wavelengths but at very fine grain sizes (less than 50 microns) this trend can be reversed and visible color becomes bluer. The extremely fine grain sizes required are consistent with the size range effectively mobilized by electrostatic levitation.

Robinson, M. S.; Thomas, P. C.; Veverka, J.; Murchie, S. L.

2001-12-01

262

Spray deposition - A summary  

NASA Astrophysics Data System (ADS)

Important findings are presented from six studies concerning the application of the Osprey metal spray-deposition process to (1) Cu-base alloys, (2) Cu-base case-hardening alloys, (3) preform formation, (4) 7075 and 8090 Al alloys, (5) superalloys, and (6) superalloy tubes. It is in the aggregate shown that while the details of the process are materials-specific, there are no technical barriers to scale-up and commercialization. Each of the alloy systems considered can be spray-formed into various near-net-shape products.

Lewis, Richard E.; Lawley, Alan

263

Deciphering human-climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500 years (Misten bog, Belgium)  

NASA Astrophysics Data System (ADS)

A high-resolution peat record from Eastern Belgium reveals the chronology of dust deposition for the last 2500 years. REE and lithogenic elements in addition to Nd and Pb isotopes were measured in a 173 cm age-dated peat profile and provide a continuous chronology of dust source and intensity. Calculated dust flux show pronounced increases c. 300 BC, 600 AD, 1000 AD, 1200 AD and from 1700 AD, corresponding to local and regional human activities combined with climate change. The Industrial Revolution samples (1700-1950 AD) are characterised by a significant enrichment in Sc-normalised REE abundance (sum REE/Sc > 25) due to intensive coal combustion. For the pre-Industrial Revolution samples, the Sc-normalised REE abundance (10 < Sum REE/Sc < 25) and the ?Nd variability (-13 to -9) are interpreted by a mixing between dust particles from local soils and long-range transport of desert particles. Three periods characterised by dominant-distal sources (c. 320 AD, 1000 AD and 1700 AD) are consistent with local wetter-than-average intervals as indicated by a lower degree of peat humification. Local erosion prevails during the drier (higher humification) intervals (100 AD, 600 AD). On a global scale, more distal supplies are driven during colder periods, in particular during the Oort and Maunder minima, suggesting a potential link between dust deposition and global climate. Combining REE abundance, fractionation between Light REE and Heavy REE and Nd isotope data in ombrotrophic peat allows one to distinguish between dust flux changes related to human and climate forcings.

Fagel, N.; Allan, M.; Le Roux, G.; Mattielli, N.; Piotrowska, N.; Sikorski, J.

2014-06-01

264

Magnetic hierarchical deposition  

NASA Astrophysics Data System (ADS)

We consider random deposition of debris or blocks on a line, with block sizes following a rigorous hierarchy: the linear size equals 1/?n in generation n, in terms of a rescaling factor ?. Without interactions between the blocks, this model is described by a logarithmic fractal, studied previously, which is characterized by a constant increment of the length, area or volume upon proliferation. We study to what extent the logarithmic fractality survives, if each block is equipped with an Ising (pseudo-)spin s=±1 and the interactions between those spins are switched on (ranging from antiferromagnetic to ferromagnetic). It turns out that the dependence of the surface topology on the interaction sign and strength is not trivial. For instance, deep in the ferromagnetic regime, our numerical experiments and analytical results reveal a sharp crossover from a Euclidean transient, consisting of aggregated domains of aligned spins, to an asymptotic logarithmic fractal growth. In contrast, deep into the antiferromagnetic regime the surface roughness is important and is shown analytically to be controlled by vacancies induced by frustrated spins. Finally, in the weak interaction regime, we demonstrate that the non-interacting model is extremal in the sense that the effect of the introduction of interactions is only quadratic in the magnetic coupling strength. In all regimes, we demonstrate the adequacy of a mean-field approximation whenever vacancies are rare. In sum, the logarithmic fractal character is robust with respect to the introduction of spatial correlations in the hierarchical deposition process.

Posazhennikova, Anna I.; Indekeu, Joseph O.

2014-11-01

265

Nitrogen fixation in boreal peatlands: the effects of increased N deposition on N2-fixation  

NASA Astrophysics Data System (ADS)

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.

Popma, J. M.; Wieder, R.; Lamers, L.; Vile, M. A.

2013-12-01

266

Global deposition of airborne dioxin.  

PubMed

We present a global dioxin model that simulates one year of atmospheric emissions, transport processes, and depositions to the earth's terrestrial and marine habitats. We map starting emission levels for each land area, and we also map the resulting deposits to terrestrial and marine environments. This model confirms that 'hot spots' of deposition are likely to be in northern Europe, eastern North America, and in parts of Asia with the highest marine dioxin depositions being the northeast and northwest Atlantic, western Pacific, northern Indian Ocean and the Mediterranean. It also reveals that approximately 40% of airborne dioxin emissions are deposited to marine environments and that many countries in Africa receive more dioxin than they produce, which results in these countries being disproportionately impacted. Since human exposure to dioxin is largely through diet, this work highlights food producing areas that receive higher atmospheric deposits of dioxin than others. PMID:23962732

Booth, Shawn; Hui, Joe; Alojado, Zoraida; Lam, Vicky; Cheung, William; Zeller, Dirk; Steyn, Douw; Pauly, Daniel

2013-10-15

267

Lunar western limb pyroclastic deposits  

NASA Technical Reports Server (NTRS)

It has become increasingly evident that the lunar pyroclastic volcanism played an important role in the formation and resurfacing of many areas of the Moon. On-going analysis of lunar Orbiter and Apollo photographs continues to locate and identify pyroclastic deposits and suggests that they just may be more ubiquitous than once thought. Located near mare/highland boundaries, many of these deposits formed contemporaneously with effusive mare volcanism. The mantling deposits formed as products of fire-fountaining. Probable source vents for these deposits include irregular depressions at the head of associated sinuous rilles and/or along irregular fractures in the floors of ancient craters. Here, researchers provide a brief synopsis of the nature of the dark mantling deposits and briefly discuss several newly identified deposits on the western limb.

Coombs, Cassandra R.; Hawke, B. Ray

1991-01-01

268

Sputter Deposition of Metallic Sponges  

Microsoft Academic Search

Metallic films are grown with a sponge-like morphology in the as-deposited condition using planar magnetron sputtering. The morphology of the deposit is characterized by metallic continuity in three dimensions with continuous porosity on the sub-micron scale. The stabilization of the metallic sponge is directly correlated with a limited range for the sputter deposition parameters of working gas pressure and substrate

A F Jankowski; J P Hayes

2002-01-01

269

Depositing Diamondlike Carbon Films  

NASA Technical Reports Server (NTRS)

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.

Mirtich, M. J.; Sovey, J. S.; Banks, B. A.

1986-01-01

270

Atomic Layer Deposition  

NSDL National Science Digital Library

In this activity, by the Concord Consortium's Molecular Literacy project, students "undertake a simulation of the Atomic Layer Deposition (ALD) technique, a CVD process in which two complementary precursors (e.g., Al(CH3)3 and H2O) are alternatively introduced into the reaction chamber, and build an atomic scale film." The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In the activity, students are allowed to explore at their own pace in a digital environment which allows them to manipulate the variables in the simulation and create a report of the data captured. In addition to the activity, visitors will find an overview of the activity, a link to more information about how the process is used in manufacturing, and an explanation of the central concepts.

2008-09-24

271

(Acidic deposition and the environment)  

SciTech Connect

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.

Garten, C.T.; Lindberg, S.E.; Van Miegroet, H.

1990-10-24

272

The influence of climate change on recent peat accumulation patterns of Distichia muscoides cushion bogs in the high-elevation tropical Andes of Colombia  

NASA Astrophysics Data System (ADS)

Extensive cushions of Distichia muscoides found at high elevations in the Andes form deep deposits of peat and function as peatland. The location of Distichia peatlands at the highest elevations makes them susceptible to the effects of global change including global warming. Accumulation rates of organic matter are the key function of peatland ecosystems and are highly susceptible to changes in climate. This study used 210Pb chronologies to infer the recent dynamics of three Distichia muscoides peatlands located above 4000 m in elevation. Chronological markers from dated volcanic eruptions were correlated to the 210Pb chronologies of Distichia peat and validated the 210Pb chronologies. Changes in 210Pb activity with depth indicated rapid accumulation in recent times. Organic matter had a mean accumulation rate of 1400 g m-2 yr-1 during the past 10 years, with values well above the observed regional accumulation rate of 300-400 g m-2 yr-1. The same pattern was observed in peat accretion rates, with growth rates of 1-2 cm per year during the last 10 years. Cushion plants engineer their own environment, allowing the system to be less susceptible to direct changes in climate. However, the high rates of peat accretion in recent times may be originated from increasing temperatures and excess water from nearby glacier melt. However, glaciers are predicted to disappear during the next 20 years in the northern Andes, reducing water inputs in tropical high-elevation ecosystems.

Benavides, Juan C.; Vitt, Dale H.; Wieder, R. Kelman

2013-12-01

273

Optimum part deposition orientation in fused deposition modeling  

Microsoft Academic Search

Surface finish and part deposition time are two important concerns in rapid prototyping (RP). These two concerns contradict with each other. Generally, a compromise is made between the two aspects pertaining to model building in RP. A compromise between these two contradicting issues can be achieved by using an adaptive slicing scheme; however, selection of a proper part deposition orientation

K Thrimurthulu; Pulak M Pandey; N Venkata Reddy

2004-01-01

274

Plasma Energetic in Pulsed Laser Deposition and Pulsed Electron Deposition  

Microsoft Academic Search

Surface bombardment by energetic particles strongly affects thin film growth and allows surface processing under non-thermal equilibrium conditions. Deposition techniques enabling energy control can effectively manipulate the microstructure of the film and tune the resulting mechanical, electrical and optical properties. At the high power densities used for depositing stoichiometric films in the case pulsed ablation techniques such as Pulsed Laser

Solomon Kolagani

2009-01-01

275

76 FR 41392 - Interest on Deposits; Deposit Insurance Coverage  

Federal Register 2010, 2011, 2012, 2013

...expense by offering interest payments to accounts...substitute for paying interest on demand deposit accounts...which funds are swept overnight from a demand deposit...The institution pays interest on the funds while they...rigorously. Interest rates are currently at a...

2011-07-14

276

Enhanced nitrogen deposition over China.  

PubMed

China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8?kilograms of nitrogen per hectare (P?deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4(+)) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3(-)), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment. PMID:23426264

Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Vitousek, Peter; Erisman, Jan Willem; Goulding, Keith; Christie, Peter; Fangmeier, Andreas; Zhang, Fusuo

2013-02-28

277

Variable temperature semiconductor film deposition  

DOEpatents

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.

Li, Xiaonan (Golden, CO); Sheldon, Peter (Lakewood, CO)

1998-01-01

278

Variable temperature semiconductor film deposition  

DOEpatents

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.

Li, X.; Sheldon, P.

1998-01-27

279

Acid rain and dry deposition  

Microsoft Academic Search

This book provides information on the formation of acid rain and the long-range transport of air pollutants. The effects of acid precipitation on both terrestrial and aquatic ecosystems are highlighted and technical and policy issues associated with the delineation and implementation of control strategies for acid rain and dry deposition are covered. Dry deposition is addressed, with emphasis given to

Canter

1985-01-01

280

Geochemistry of sedimentary ore deposits  

SciTech Connect

A text providing a sedimentological treatment of a study on ore deposits, and especially as related to geochemistry. Excellently documented (about 5000 citations). Well indexed with the index of deposits and localities separated. Contents, Iron. Copper and silver. Aluminum and nickel. Manganese. Uranium. Lead and zinc. Volcanic-sedimentary ores. Appendix. Indexes.

Maynard, J. B.

1983-01-01

281

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...

282

TULSA UNIVERSITY PARAFFIN DEPOSITION PROJECTS  

Microsoft Academic Search

As oil and gas production moves to deeper and colder water, subsea multiphase production systems become critical for economic feasibility. It will also become increasingly imperative to adequately identify the conditions for paraffin precipitation and predict paraffin deposition rates to optimize the design and operation of these multiphase production systems. Although several oil companies have paraffin deposition predictive capabilities for

Michael Volk; Cem Sarica

2003-01-01

283

TULSA UNIVERSITY PARAFFIN DEPOSITION PROJECTS  

Microsoft Academic Search

As oil and gas production moves to deeper and colder water, subsea multiphase production systems become critical for economic feasibility. It will also become increasingly imperative to adequately identify the conditions for paraffin precipitation and predict paraffin deposition rates to optimize the design and operation of these multi-phase production systems. Although several oil companies have paraffin deposition predictive capabilities for

Cem Sarica; Michael Volk

2004-01-01

284

Vacuum vapor deposition  

NASA Technical Reports Server (NTRS)

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.

Poorman, Richard M. (inventor); Weeks, Jack L. (inventor)

1995-01-01

285

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

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 an existing vertical-chamber 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 impurity diffusion and other standard and near-standard processing techniques supplemented late in the program by the in situ CVD growth of n(+)/p/p(+) sheet structures subsequently processed into experimental cells.

Ruth, R. P.; Manasevit, H. M.; Campbell, A. G.; Johnson, R. E.; Kenty, J. L.; Moudy, L. A.; Shaw, G. L.; Simpson, W. I.; Yang, J. J.

1978-01-01

286

Environmental Studies of Mineral Deposits in Alaska  

NSDL National Science Digital Library

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.

1996-01-01

287

Principal uranium deposits of the world  

Microsoft Academic Search

The geology of the principal world uranium deposits that have identified uranium reserves and production is summarized including type of deposit, host rock and age of host rock, age of mineralization, depositional environment, and mineralogy. The deposits grouped on maps according to age of host rocks - Precambrian, Paleozoic, Mesozoic, and Cenozoic - and further subdivided into types of deposits

1978-01-01

288

Vapor deposition of tantalum and tantalum compounds  

Microsoft Academic Search

Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the

Trkula

1996-01-01

289

Deposition + Erosion = Textures  

NASA Technical Reports Server (NTRS)

[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.

2003-01-01

290

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 ...

291

Jet aircraft fuel system deposits  

SciTech Connect

Deposits samples were from the valve cavity of a fuel nozzle of a CF6-50A engine, from the fuel manifold adjacent to the combustor nozzles of a TR-30 engine, fuel test devices, and heat exchange tubes, operated in the laboratories of the Naval Air Propulsion Center and the Air Force Aero Propulsion Laboratory. Carbon, hydrogen, nitrogen and oxygen in the deposits were determined with a Perkin Elmer Elemental Analyzer. Sulfur was determined on a separate sample by modifying ASTM method D3120-75. The high amount of oxygen, nitrogen and sulfur found in the deposits is noteworthy. The data reported generally corroborates the information from the literature. All of the deposits from the engines and the test devices point to the importance of compounds containing hereto atoms. The importance of oxidation in triggering solids formation has been reviewed. It would appear that the trace primary oxidation reactions occurring in a fuel system would be insufficient to give the high concentration of oxygen in the deposit. However, if the compounds undergoing oxidation were oxygen-containing compounds rather than hydrocarbons the high oxygen concentrations in the deposit would be more reasonable. The high enhancement factors observed, causes one to conclude that some nitrogen and sulfur compounds found in fuels are very susceptible to oxidation and subsequent deposit formation. The high concentrations of hereto atoms implies that the deposits have highly polar characteristics. Since such material would have little attraction for the non-polar fuel, the insolubility of deposits may be due primarily to polarity differences rather than high molecular weight.

Hazlett, R.N.; Hall, J.M.

1981-03-01

292

Comparison of High-Resolution Depositional Records of Hillslope and Fluvial-Dominated Catchments, San Gabriel Mountains, CA  

NASA Astrophysics Data System (ADS)

Paleoseismic records from the San Gabriel Mountains, CA provide high stratigraphic resolution, carefully dated records that can be mined for interactions between sediment routing, climate change, and punctuated influence by earthquakes. To explore linkages between hillslope- and fluvial-dominated catchments I compare the depositional record of two closely-spaced but different-sized sites. The Wrightwood paleoseismic site (elev 1900 m) is an upland bog that receives hyperconcentrated and debris flows from a steep 1 km2 catchment. From A.D. 600 to 1850, individual flows occur on average every 37 years and the average sedimentation rate (0.6 mm/yr) is similar to published estimates of bedrock erosion rates in the San Gabriels. Three short periods of high flow frequency (12 yr) and fast sedimentation rates (2 cm/yr) provide roughly 50% of the sediment available to the fluvial system in only 350 years. These three periods of high sedimentation rates at Wrightwood also contain half of the 14 paleoearthquake record, suggesting that earthquakes and increased sediment production are correlated in this small catchment located close to the fault. The Pallett Creek site sits at a lower elevation (1090 m), is fed by a larger catchment (100 km2), and the depositional record consists of interbedded stream, aeolian, and marsh deposits (Sieh, 1978). From A.D. 600 to 1850, sandy deposits recur roughly every 25 years; one large flood event ~1000 years ago left thick gravel layer across the site. Lower slopes and greater average distance from the fault at Pallett Creek appear to diminish the shared signal of earthquakes and sedimentation rates documented at Wrightwood. However, the climate record shows systematic variation with both sites: pollen and vegetation records in southern California show a move to wetter climate after AD 1200 - 1400. This recent wet period coincides with a decrease in the average thickness of the clastic deposits at Wrightwood and an increase in the thickness of organic layers at Pallett Creek, suggesting that wetter climates transport less sediment off the slopes and into the fluvial system on the northern flanks of the San Gabriels, and/or that other processes (fire frequency, vegetative change?) cause increased sedimentation during drier periods.

Scharer, K.

2008-12-01

293

CALCIUM CARBONATE DEPOSITION IN GEOTHERMAL WELLBORES  

E-print Network

CALCIUM CARBONATE DEPOSITION IN GEOTHERMAL WELLBORES MIRAVALLES GEOTHERMAL FIELD COSTA RICA CALCIUM CARBONATE DEPOSITION IN GEOTHERMAL WELLBORES MIRAVALLES GEOTHERMAL FIELD COSTA RICA BY Eduardo University. #12;ABSTRACT Calcium carbonate deposition takes place in the wells of the Miravalles geothermal

Stanford University

294

Direct Deposit _Job Aid March 2012 Page 1 of 7 Direct Deposit Online Instructions Job Aid  

E-print Network

Direct Deposit _Job Aid March 2012 Page 1 of 7 Direct Deposit Online Instructions ­ Job Aid of this job aid is to provide you with the steps to add, edit or inactivate your direct deposit information Deposit within Self Service in PAC. Direct Deposit myColumbia Portal PAC Links #12;Direct Deposit _Job Aid

Grishok, Alla

295

Seasonalepisodic control of acid deposition  

E-print Network

This report contains the climatological, technical and economic factors for episodic and seasonal control of emissions in existing power plants. Analyzing a large data set of acid deposition for the years 1982-85, we find ...

Fay, James A.

1988-01-01

296

Liquefaction in Deposits of River  

USGS Multimedia Gallery

Liquefaction in recent deposits of San Lorenzo River caused cracking and differential settling of river levee southeast of Riverside Avenue Bridge. Bridge piers and the north abutment area were also damaged by liquefaction....

2009-01-26

297

Online Deposit Agreement The parties  

E-print Network

abstract, if necessary, and to disseminate the Work via Intranet and Internet. USI is under no obligation the systems employed for the online deposit of the Work. The Author renounces to sue USI for any hacking

Krause, Rolf

298

Modeling Deposition of Inhaled Particles  

EPA Science Inventory

The mathematical modeling of the deposition and distribution of inhaled aerosols within human lungs is an invaluable tool in predicting both the health risks associated with inhaled environmental aerosols and the therapeutic dose delivered by inhaled pharmacological drugs. Howeve...

299

Deposition of general ellipsoidal particles  

NASA Astrophysics Data System (ADS)

We present a systematic overview of granular deposits composed of ellipsoidal particles with different particle shapes and size polydispersities. We study the density and anisotropy of such deposits as functions of small to moderate size polydispersity and two shape parameters that fully describe the shape of a general ellipsoid. Our results show that, while shape influences significantly the macroscopic properties of the deposits, polydispersity in the studied range plays apparently a secondary role. The density attains a maximum for a particular family of nonsymmetrical ellipsoids, larger than the density observed for prolate or oblate ellipsoids. As for anisotropy measures, the contact forces are increasingly preferred along the vertical direction as the shape of the particles deviates from a sphere. The deposits are constructed by means of a molecular dynamics method, where the contact forces are efficiently and accurately computed. The main results are discussed in the light of applications for porous media models and sedimentation processes.

Baram, Reza M.; Lind, Pedro G.

2012-04-01

300

Deposition of general ellipsoidal particles.  

PubMed

We present a systematic overview of granular deposits composed of ellipsoidal particles with different particle shapes and size polydispersities. We study the density and anisotropy of such deposits as functions of small to moderate size polydispersity and two shape parameters that fully describe the shape of a general ellipsoid. Our results show that, while shape influences significantly the macroscopic properties of the deposits, polydispersity in the studied range plays apparently a secondary role. The density attains a maximum for a particular family of nonsymmetrical ellipsoids, larger than the density observed for prolate or oblate ellipsoids. As for anisotropy measures, the contact forces are increasingly preferred along the vertical direction as the shape of the particles deviates from a sphere. The deposits are constructed by means of a molecular dynamics method, where the contact forces are efficiently and accurately computed. The main results are discussed in the light of applications for porous media models and sedimentation processes. PMID:22680463

Baram, Reza M; Lind, Pedro G

2012-04-01

301

Plasma deposition of oxide cathodes  

NASA Astrophysics Data System (ADS)

Vacuum arc deposition is employed to create a barium and/or strontium plasma which is subsequently deposited/implanted onto a nickel cathode substrate. The primary motivation for this work is the critical need for a reliable, repeatable, long-lived thermionic cathode for the production of high power, microsecond duration microwave pulses; such cathodes may also have applicability for lower current density continuous wave devices. This novel approach to manufacturing an oxide cathode eliminates the binders that may subsequently (and unpredictably) poison cathode emission. Removal of the poisoning mechanisms has yielded oxide cathodes capable of emission densities in the 20 A/cm2 regime. Cathode lifetime and emission may be varied via the control over the deposition parameters such as coating thickness, implantation energy, and plasma stoichiometry. The deposition is performed by generating a cathodic arc discharge at the surface of a barium or barium-strontium alloy rod. The metal plasma thus created is then deposited on the substrate which can be negatively biased to encourage implantation during the deposition process. The deposition is performed with sufficient background oxygen present to oxidize the highly reactive metal coating. The plasma deposition is monitored via a rate thickness monitor, an optical emission spectrometer for plasma composition information, and an electrostatic Langmuir probe for the determination of the plasma density and temperature profile. Cathodes thus produced are analyzed by drawing pulsed current at a constant voltage for various values of decreasing cathode temperature in order to generate practical work function distributions which provide an indication of the quality and expected life time of the cathode. In support of analyzing these cathodes (as well as a variety of cathodes from other sources), a complete UHV cathode test and analysis system has been assembled which includes 3-D beam profiling, advanced temperature measurement, residual gas analysis, bulk cold work function measurement, and surface analysis with depth profiling.

Umstattd, R.; Pi, T.; Luhmann, N.; Scheitrum, G.; Caryotakis, G.; Miram, G.

1999-05-01

302

Plasma deposition of oxide cathodes  

Microsoft Academic Search

Vacuum arc deposition is employed to create a barium and\\/or strontium plasma which is subsequently deposited\\/implanted onto a nickel cathode substrate. The primary motivation for this work is the critical need for a reliable, repeatable, long-lived thermionic cathode for the production of high power, microsecond duration microwave pulses; such cathodes may also have applicability for lower current density continuous wave

R. Umstattd; T. Pi; N. Luhmann; G. Scheitrum; G. Caryotakis; G. Miram

1999-01-01

303

Chemical enhancement of surface deposition  

DOEpatents

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.

Patch, K.D.; Morgan, D.T.

1997-07-29

304

Chemical enhancement of surface deposition  

DOEpatents

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.

Patch, Keith D. (Lexington, MA); Morgan, Dean T. (Sudbury, MA)

1997-07-29

305

U-Pb SHRIMP dating of uraniferous opals  

USGS Publications Warehouse

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.

Nemchin, A.A.; Neymark, L.A.; Simons, S.L.

2006-01-01

306

Characterization of zirconium thin films deposited by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Zirconium (Zr) thin films deposited on Si (100) by pulsed laser deposition (PLD) at different pulse repetition rates are investigated. The deposited Zr films exhibit a polycrystalline structure, and the X-ray diffraction (XRD) patterns of the films show the ? Zr phase. Due to the morphology variation of the target and the laser—plasma interaction, the deposition rate significantly decreases from 0.0431 Å/pulse at 2 Hz to 0.0189 Å/pulse at 20 Hz. The presence of droplets on the surface of the deposited film, which is one of the main disadvantages of the PLD, is observed at various pulse repetition rates. Statistical results show that the dimension and the density of the droplets increase with an increasing pulse repetition rate. We find that the source of droplets is the liquid layer formed under the target surface. The dense nanoparticles covered on the film surface are observed through atomic force microscopy (AFM). The root mean square (RMS) roughness caused by valleys and islands on the film surface initially increases and then decreases with the increasing pulse repetition rate. The results of our investigation will be useful to optimize the synthesis conditions of the Zr films.

Liu, Wei; Wan, Jing-Ping; Cai, Wu-Peng; Liang, Jian-Hua; Zhou, Xiao-Song; Long, Xing-Gui

2014-09-01

307

Metal film deposition by laser breakdown chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Dielectric breakdown of gas mixtures can be used to deposit homogeneous thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas phase nucleation and particle formation. Using a pulsed CO2 laser operating at 10.6 microns where there is no significant resonant absorption in any of the source gases, we have succeeded in depositing homogeneous films from several gas phase precursors by gas phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls and tungsten from the hexafluoride have been examined to date. In each case the gas precursor is buffered to reduce the partial pressure of the reactants and to induce breakdown. The films are spectrally reflective and uniform over a large area. Films have been characterized by Auger electron spectroscopy, X-ray diffraction, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed X-ray diffraction analysis of these films yields a very small domain size (approx. 50 A) consistent with rapid quenching from the gas phase reaction zone. This analysis also shows nickel carbide formation consistent with the temperature of the reaction zone and the Auger electron spectroscopy results which show some carbon and oxygen incorporation (8% and 1% respectively). Gas phase transport and condensation of the molybdenum carbonyl results in substantial carbon and oxygen contamination of the molybdenum films requiring heated substrates, a requirement not consistent with the goals of the program to maximize the quench rate of the deposition. Results from tungsten deposition experiments representing a reduction chemistry instead of the decomposition chemistry involved in the carbonyl experiments are also reported.

Jervis, T. R.

1985-01-01

308

AZO electrodes deposited by atomic layer deposition for OLED fabrication  

NASA Astrophysics Data System (ADS)

In this work, we present a comparative study of optimized AZO electrodes deposited by Atomic Layer Deposition (ALD) with commercial ITO in terms of electrical, optical and structural properties. Despite a lower figure of merit mainly due to a higher sheet resistance, AZO-based OLEDs are shown to present a current density five times higher than ITO-based ones for the same applied voltage. These AZO electrodes fabricated by ALD could thus be promising substitutes for conventional ITO anodes in organic electronic devices.

Dugrenil, B.; Séguy, I.; Lee, Hsin-Ying; Camps, T.; Lin, Y.-C.; Doucet, J. B.; Chiu, Y.-S.; Salvagnac, L.; Bedel-Pereira, E.; Ternisien, M.; Lee, C. T.; Bardinal, V.

2014-05-01

309

Deposition of ozone to tundra  

NASA Technical Reports Server (NTRS)

Eddy correlation measurements of O3 deposition fluxes to tundra during the Arctic Boundary Layer Expedition (ABLE 3A) are reported. The mean O3 deposition velocity was 0.24 cm/s in the daytime and 0.12 cm/s at night. The day-to-day difference in deposition velocity was driven by both atmospheric stability and surface reactivity. The mean surface resistance to O3 deposition was 2.6 s/cm in the daytime and 3.4 s/cm at night. The relatively low surface resistance at night is attributed to light-insensitive uptake of O3 at dry upland tundra surfaces. The small day-tonight difference in surface resistance is attributed to additional stomatal uptake by wet meadow tundra plants in the daytime. The mean O3 deposition flux to the world north of 60 deg N in July-August is estimated at 8.2 x 10 exp 10 molecules/sq cm/s. Suppression of photochemical loss by small anthropogenic inputs of nitrogen oxides could have a major effect on O3 concentrations in the summertime Arctic troposphere.

Jacob, D. J.; Fan, S.-M.; Wofsy, S. C.; Spiro, P. A.; Bakwin, P. S.; Ritter, J. A.; Browell, E. V.; Gregory, G. L.; Fitzjarrald, D. R.; Moore, K. E.

1992-01-01

310

Deposition of ozone to tundra  

SciTech Connect

Eddy correlation measurements of O3 deposition fluxes to tundra during the Arctic Boundary Layer Expedition (ABLE 3A) are reported. The mean O[sub 3] deposition velocity was 0.24 cm/s in the daytime and 0.12 cm/s at night. The day-to-day difference in deposition velocity was driven by both atmospheric stability and surface reactivity. The mean surface resistance to O[sub 3] deposition was 2.6 s/cm in the daytime and 3.4 s/cm at night. The relatively low surface resistance at night is attributed to light-insensitive uptake of O[sub 3] at dry upland tundra surfaces. The small day-tonight difference in surface resistance is attributed to additional stomatal uptake by wet meadow tundra plants in the daytime. The mean O[sub 3] deposition flux to the world north of 60 deg N in July-August is estimated at 8.2 x 10 exp 10 molecules/sq cm/s. Suppression of photochemical loss by small anthropogenic inputs of nitrogen oxides could have a major effect on O[sub 3] concentrations in the summertime Arctic troposphere. 34 refs.

Jacob, D.J.; Fan, S.M.; Wofsy, S.C.; Spiro, P.A.; Bakwin, P.S.; Ritter, J.A.; Browell, E.V.; Gregory, G.L.; Fitzjarrald, D.R.; Moore, K.E. (Harvard Univ., Cambridge, MA (United States) NASA, Langley Research Center, Hampton, VA (United States) New York State Univ., Albany (United States))

1992-10-01

311

Challenges for ionized physical vapor deposition  

Microsoft Academic Search

Summary form only given. Vapor deposition using ionic species has several advantages over neutral vapor deposition methods. These include the ability to use the electric field within the plasma sheath to modify the energy and direction of the depositing particle. Energetic deposition allows one to produce thin film materials with tailored properties. The control of particle direction, on the other

J. A. Hopwood; D. Mao

2004-01-01

312

Acid deposition and forest decline  

SciTech Connect

The available evidence does not show a clear cause and effect relationship between acid deposition and forest decline and dieback in the US. The second of two articles examines soil and vegetation changes, summarizes the theories on spruce and fir dieback in Central Europe, and assesses the possible natural and manmade causes. The location, topography and other characteristics of the high-elevation forests of eastern North America cause them to be receptors of high levels of acid deposition and airborn trace metals. The authors find several possible pathways for acid deposition to contribute to spruce mortality, but none are supported by convincing evidence. However, there is evidence for the triggering effect of drought in a situation of multiple stresses. 55 references, 13 figures, 1 table.

Johnson, A.H.; Siccama, T.G.

1983-01-01

313

National Atmospheric Deposition Program (NADP)  

NSDL National Science Digital Library

Hosted by the University of Illinois at Urbana-Champaign, The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) is an excellent resource for precipitation data. Network collaborators include the State Agricultural Experiment Stations, U.S. Geological Survey, U.S. Department of Agriculture, along with many other government agencies, universities and private organizations. "The purpose of the network is to collect data on the chemistry of precipitation for monitoring of geographical and temporal long-term trends." At this site, users may search out weekly and daily precipitation chemistry data, isopleth maps, mercury deposition data, annual and seasonal deposition totals, and much more. Users should note, there is a five to six month time lag between data collection dates and data availability on the Website.

314

Evaporative Deposition in Receding Drops  

E-print Network

We present a framework for calculating the surface density profile of a stain deposited by a drop with a receding contact line. Unlike a pinned drop, a receding drop pushes fluid towards its interior, continuously deposits mass across its substrate as it evaporates, and does not produce the usual "coffee ring." For a thin, circular drop with a constant evaporation rate, we find the surface density of the stain goes as $\\eta(r) \\propto \\left(\\left(r/a_0\\right)^{-1/2}-r/a_0\\right)$, where $r$ is the radius from the drop center and $a_0$ is the initial outer radius. Under these conditions, the deposited stain has a mountain-like morphology. Our framework can easily be extended to investigate new stain morphologies left by drying drops.

Julian Freed-Brown

2014-10-02

315

Evaporative deposition in receding drops.  

PubMed

We present a framework for calculating the surface density profile of a stain deposited by a drop with a receding contact line. Unlike a pinned drop, a receding drop pushes fluid towards its interior, continuously deposits mass across its substrate as it evaporates, and does not produce the usual "coffee ring." For a thin, circular drop with a uniform evaporation rate, we find the surface density of the stain goes as ?(r) ? ((r/a0)(-1/2)-r/a0), where r is the radius from the drop center and a0 is the initial outer radius. Under these conditions, the deposited stain has a mountain-like morphology. Our framework can easily be extended to investigate new stain morphologies left by drying drops. PMID:25350152

Freed-Brown, Julian

2014-12-21

316

Inhomogeneity of calcium phosphate coatings deposited by laser ablation at high deposition rate  

Microsoft Academic Search

Calcium phosphate coatings were deposited with a KrF excimer laser onto titanium alloy to study their homogeneity. Deposition was performed at a high deposition rate under a water vapour atmosphere of 45 Pa and at a substrate temperature of 575 °C. Samples were also submitted to annealing under the same conditions of deposition for different times just after deposition. The

J. M. Fernández-Pradas; G. Sardin; J. L. Morenza

2003-01-01

317

OXALATE DEPOSITION ON ASBESTOS BODIES  

EPA Science Inventory

The clinical and histopathologic findings in three patients with a deposition of calcium oxalate crystals on ferruginous bodies after occupational exposure to asbestos are provided. In addition, we test the hypothesis that this oxalate can be generated through a nonenzymatic o...

318

Energy deposition in antimatter meteors  

Microsoft Academic Search

Antimatter meteors, like ordinary ones, can be heated during their infall flight. However, this could happen by a completely different process than in the case of koinomatter meteors, since in the latter case the annihilation interactions mechanism is absent. In case of antimatter meteors, the temperature may be increased mainly due to the energy deposition effect, caused by the passage

P. M. Papaelias

1991-01-01

319

Acoustic monitoring of electrochemical deposition  

Microsoft Academic Search

In the microelectronics industry, manufacturers are concerned with increasing yield and reducing costs. Monitoring of unit manufacturing processes helps alleviate errors during fabrication, thereby increasing yield and ultimately decreasing cost. This work proposes an acoustic method for in-situ monitoring of electrochemical deposition. A micromachined acoustic sensor was developed for this purpose. During electroplating processes, changes in the plating solution composition

Frances R. Williams; Gary S. May

2004-01-01

320

EVALUATION OF MONAZITE PLACER DEPOSITS  

Microsoft Academic Search

New techaiques are described which are employed for evaluation of ; monazite deposits. The presence of other radioactive minerals hesides monazite, ; such as uranothorite, samarskite, euxenite, furgusonite, brannerite, xenotime, ; zircon and others, make a triple check--radiometric, chemical, and mineralogic---; analysis desirable. Information is given on the different methods used in field ; operations, in field laboratories and in

Kline

1952-01-01

321

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...

322

Tumoral calcium pyrophosphate deposition disease  

Microsoft Academic Search

A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a women aged 71 years, the lesion involved the tissues

Hubert A. Sissons; German C. Steiner; Fiona Bonar; Michael May; Zehava S. Rosenberg; Hershel Samuels

1989-01-01

323

FDIC: Federal Deposit Insurance Corporation  

NSDL National Science Digital Library

The U.S. Federal Deposit Insurance Corporation WWW Home Page is open for business. At this site, there is information on the U.S. banking industry, financial information on the condition of the Bank Insurance Fund and the Savings Association Insurance Fund, consumer information, and press releases.

324

Chemical deposition of conducting polymers  

Microsoft Academic Search

The coating of different materials with conducting electroactive polymers (CEP), i.e. polyaniline, polypyrrole, polythiophene, and their derivatives, provided by means of chemical polymerization, is briefly reviewed. The topics covered include the deposition of CEP (i) by bulk oxidative chemical polymerization, (ii) by surface-located polymerization, and (iii) by coating of micro- and nanoparticles. The coating of different materials like polymers, polymer

A. Malinauskas

2001-01-01

325

ATMOSPHERIC MERCURY TRANSPORT AND DEPOSITION  

EPA Science Inventory

The current state of our scientific understanding the mercury cycle tells us that most of the mercury getting into fish comes from atmospheric deposition, but methylation of that mercury in aquatic systems is required for the concentrations in fish to reach harmful levels. We st...

326

Simple Chemical Vapor Deposition Experiment  

ERIC Educational Resources Information Center

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…

Pedersen, Henrik

2014-01-01

327

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...

328

Liquefaction in Deposits of River  

USGS Multimedia Gallery

Liquefaction in recent deposits of the Pajaro River formed these sand volcanoes along extensional fissures in a field prepared for autumn planting near Pajaro, across the Pajaro River from Watsonville. Furrows are spaced about 1.2 m (4 ft) apart....

2009-01-26

329

Ecophysiology in an ombrotrophic spruce bog  

E-print Network

to assess the response of northern peatland ecosystems to increases in temperature and exposures to elevated Northern Research Station at the Marcell Experimental Forest in northern Minnesota Sponsored by the Office in response to light (light response curves) Photosynthesis in response to CO2 (A-Ci curves) #12;4 Managed

330

THE BOG TURTLE: Georgia's Rarest Turtle.  

ERIC Educational Resources Information Center

This article discusses the description and range, the status, the habitat, the natural history, and the proper management of the diminutive, rare, and endangered species known as the box turtle. (JJK)

Wilson, Lawrence

1991-01-01

331

Ion beam sputter deposited diamond like films  

NASA Technical Reports Server (NTRS)

A single argon ion beam source was used to sputter deposit carbon films on fused silica, copper, and tantalum substrates under conditions of sputter deposition alone and sputter deposition combined with simultaneous argon ion bombardment. Simultaneously deposited and ion bombarded carbon films were prepared under conditions of carbon atom removal to arrival ratios of 0, 0.036, and 0.71. Deposition and etch rates were measured for films on fused silica substrates. Resulting characteristics of the deposited films are: electrical resistivity of densities of 2.1 gm/cu cm for sputter deposited films and 2.2 gm/cu cm for simultaneously sputter deposited and Ar ion bombarded films. For films approximately 1700 A thick deposited by either process and at 5550 A wavelength light the reflectance was 0.2, the absorptance was 0.7, the absorption coefficient was 67,000 cm to the -1 and the transmittance was 0.1.

Banks, B. A.; Rutledge, S. K.

1982-01-01

332

Low filament temperature deposition of aSi:H by hot-wire chemical vapor deposition  

Microsoft Academic Search

Hydrogenated amorphous silicon, a-Si:H, is deposited from silane and hydrogen by hot-wire chemical vapor deposition using a tungsten wire filament at a temperature Tfil=1200 °C. Film properties depend on whether the films were deposited using filaments with an accumulated deposition time lower than 90 min (‘‘new’’ filaments) or longer than 90 min (‘‘old’’ filaments). The deposition rate for films deposited

P. Brogueira; J. P. Conde; S. Arekat; V. Chu

1995-01-01

333

COMPARISON OF THE RADM (REGIONAL ACID DEPOSITION MODEL) DRY DEPOSITION MODULE WITH SITE-SPECIFIC ROUTINES FOR INFERRING DRY DEPOSITION  

EPA Science Inventory

The dry deposition module of the Regional Acid Deposition Model (RADM) is used to compute the dry deposition velocities (downward flux divided by concentration at a specified height) for SO2, SO4(2-), O3, and HNO3, among others. With its computerized landuse map, the module can p...

334

films using atomic layer deposition  

NASA Astrophysics Data System (ADS)

We fabricated self-assembled silver nanoisland films using a recently developed technique based on out-diffusion of silver from an ion-exchanged glass substrate in reducing atmosphere. We demonstrate that the position of the surface plasmon resonance of the films depends on the conditions of the film growth. The resonance can be gradually shifted up to 100 nm towards longer wavelengths by using atomic layer deposition of titania, from 3 to 100 nm in thickness, upon the film. Examination of the nanoisland films in surface-enhanced Raman spectrometry showed that, in spite of a drop of the surface-enhanced Raman spectroscopy (SERS) signal after the titania spacer deposition, the Raman signal can be observed with spacers up to 7 nm in thickness. Denser nanoisland films show slower decay of the SERS signal with the increase in spacer thickness.

Chervinskii, Semen; Matikainen, Antti; Dergachev, Alexey; Lipovskii, Andrey A.; Honkanen, Seppo

2014-08-01

335

(International conference on acidic deposition)  

SciTech Connect

The traveler took the opportunity to participate in a mini-sabbatical at the Institute of Terrestrial Ecology (ITE) in Edinburgh, Scotland, as a part of planned travel to Glasgow, Scotland, to attend the International Conference on Acidic Precipitation. The purpose of the sabbatical was to provide quality time for study and interchange of ideas with scientists at ITE working on physiological effects of acidic deposition and to allocate significant time for writing and synthesizing of results of physiological studies from the National Forest Response Program's Spruce/Fir Research Cooperative. The study focused on the very significant cytological and physiological effects of calcium deficiency in trees, a response that appears to be amplified in spruce by acidic deposition.

McLaughlin, S.B. Jr.

1990-10-05

336

Exploration strategies for hydrothermal deposits.  

PubMed

With unlimited money the most certain strategy for finding most hydrothermal metal deposits would be by drilling to 5000 m at 50 m spacing. However, the cost would far outweigh the benefit of the discoveries. Geological knowledge and exploration techniques may be used to obtain the greatest benefit for minimum cost, and to concentrate human and material resources in the most economic way in areas with the highest probability of discovery. This paper reviews the economic theory of exploration based on expected value, and the application of geological concepts and exploration techniques to exploration for hydrothermal deposits. Exploration techniques for hydrothermal-systems on Mars would include geochemistry and particularly passive geophysical methods. PMID:9243019

Horn, R A

1996-01-01

337

12 CFR 263.53 - Discovery depositions.  

...2014-01-01 2014-01-01 false Discovery depositions. 263.53 Section 263...Supplementing the Uniform Rules § 263.53 Discovery depositions. (a) In general. In addition to the discovery permitted in subpart A of this...

2014-01-01

338

Chemical vapor deposition of functionalized isobenzofuran polymers  

E-print Network

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 ...

Olsson, Ylva Kristina

2007-01-01

339

Formation mechanisms of combustion chamber deposits  

E-print Network

Combustion chamber deposits are found in virtually all internal combustion engines after a few hundred hours of operation. Deposits form on cylinder, piston, and head surfaces that are in contact with fuel-air mixture ...

O'Brien, Christopher J. (Christopher John)

2001-01-01

340

HAZARDOUS AIR POLLUTANTS: DRY-DEPOSITION PHENOMENA  

EPA Science Inventory

Dry-deposition rates were evaluated for two hazardous organic air pollutants, nitrobenzene and perchloroethylene, to determine their potential for removal from the atmosphere to three building material surfaces, cement, tar paper, and vinyl asbestos tile. Dry-deposition experimen...

341

Electrophoretic deposition of nanosized ceramic powders  

SciTech Connect

For nanosized powders the forming of compacts by electrophoretic deposition is an interesting method. In aqueous suspensions high deposition rates can be achieved at low electric fields. The problems with the gas bubble formation at the electrodes which are caused by the decomposition of water can be solved by depositing the compact on a microporous membrane in front of the electrode. Thus, with nanosized zirconia powders made by the flame hydrolysis (BET-surface area approx. 50 M{sup 2}/g) the deposition rate was measured as a function of deposition time and electrolyte concentration. Furthermore, the deposition rate depends on the effective electric field inside the suspension, which is much lower in zirconia suspensions than in comparable silica suspensions. In spite of this, deposition rates up to 0.5 g/min {center_dot} CM{sup 2} were achieved. The deposited compacts showed a small pore size distribution (max. 25 nm) and a relative green density of 40%.

Clasen, R.; Janes, S.; Oswald, C.; Ranker, D. [Institut fuer Neue Materialien gem GmbH, Saarbruechek (Germany)

1995-09-01

342

Orbital Reconnaissance of Pyroclastic Deposits on Venus  

NASA Astrophysics Data System (ADS)

A survey of volcanoes using high-resolution radar polarimetry would enable a global search for pyroclastic deposits. Identifying the locations, extents, and relative ages of these deposits is important for multiple Venus science goals.

Carter, L. M.; Campbell, D. B.; Campbell, B. A.

2014-05-01

343

Modeling deposit formation in diesel injector nozzle  

E-print Network

Formation of deposit in the diesel injector nozzle affects the injection behavior and hinders performance. Under running condition, deposit precursors are washed away by the ensuing injection. However, during the cool down ...

Sudhiesh Kumar, Chintoo

2009-01-01

344

Ion beam deposited protective films  

NASA Technical Reports Server (NTRS)

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.

Mirtich, M. J.

1981-01-01

345

Determining Historical Pesticide Deposition on Cape Cod through Sediment Core Analysis:A Validation of GIS as An Exposure Assessment Tool  

NASA Astrophysics Data System (ADS)

Geographic Information Systems (GIS) has emerged as a powerful tool to assess current and historical exposure to environmental pollutants. GIS aids in the visualization and understanding of associations between exposure to contaminants and disease. This study is an example of the bridge between environmental science and public health and of how new technology such as GIS can be incorporated into these fields to strengthen both the research and the communication of scientific results. It attempts to validate a GIS-based aerial drift model which predicts the residential exposure to and boundaries of historical organochlorine pesticide (OCP) drift from applications on cranberry bogs, tree pest sprayings and others by analytically quantifying the historical pesticide deposition in a transect of lakes radiating from a distinct spray source. This model was previously used to assess historical residential exposure to OCPs in an environmental epidemiological case-control study of breast cancer incidence on Cape Cod, MA, where the incidence rate of the disease is significantly higher than in the rest of the state. The model's validation in this current study is essential to establishing its predictive ability and thus, its further use. Ground truthing of the model was done through the collection and analysis of sediment cores along a transect of five hydrologically independent kettle ponds radiating from a distinct OCP tree-pest spray area. Measurements of OCP concentrations, total carbon and total organic carbon were determined, and dating of the sediments was completed using 210Pb and verified using 137Cs. Each 50-cm core was sliced into 25 2- cm sections for the analyses, creating a fine-scale depositional history in each pond. Information gathered from each core allows for the determination of the extent and degree of dissipation of individual spray events of a known source area and determine how well the model fits the actual data.

Feingold, B. J.; Benoit, G.; Rudel, R.

2006-12-01

346

Fog deposition to the Atacama desert  

Microsoft Academic Search

In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water

A. Westbeld; O. Klemm; F. Griessbaum; E. Sträter; H. Larrain; P. Osses; P. Cereceda

2010-01-01

347

CALCULATION OF ION ENERGY-DEPOSITION SPECTRA  

E-print Network

CALCULATION OF ION ENERGY-DEPOSITION SPECTRA IN SILICON, LITHIUM-FLUORIDE, BORON, AND BORON CARBIDE applications it is important to be able to calculate the energy deposited in the medium through which the ions for calculating the energy-deposition spectrum in various materials is presented and then applied to the design

Shultis, J. Kenneth

348

Atmospheric deposition maps for the Rocky Mountains  

Microsoft Academic Search

Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountains by using spatial statistics. A parameter-elevation regressions on

Leora Nanus; Donald H. Campbell; George P. Ingersoll; David W. Clow; M. Alisa Mast

2003-01-01

349

Utility guidelines for controlled deposition repair welding  

SciTech Connect

This paper reviews experimental results from the EQI work performed to develop controlled deposition repairs for Cr-Mo steels without postweld heat treatment (PWHT) which are pertinent to electric utility applications, gives recommended guidelines for evaluating if controlled deposition welding is appropriate for a particular repair, and provides a listing of potential applications for controlled deposition repair welding.

Neary, C.M. [Pacific Gas and Electric Co., San Ramon, CA (United States)

1996-06-01

350

Electrospark Deposition by Using Powder Materials  

Microsoft Academic Search

Electrical discharges can be used to improve the operational properties of the surface layer of parts by using the phenomena of tempering, alloying, and deposition. Various techniques of alloying or deposition have been studied so far and sometimes even applied in the industry. The systemic approach of the deposition process shows which input and output factors can be taken into

Pavel Topal?; Lauren?iu Sl?tineanu; Oana Dodun; Margareta Cotea??; Natalia P?nzaru

2010-01-01

351

Wide band antireflection coatings deposited by atomic layer deposition  

NASA Astrophysics Data System (ADS)

Here we describe the development of optical coatings for silicon-based detectors for astronomy, planetary and terrestrial applications. We have used atomic layer deposition (ALD) to develop broadband (i.e. 320-1000 nm) antireflection (AR) coatings on silicon substrates with the ultimate goal of incorporating these AR coatings with existing detector technologies. Materials characterization was used to study film and interface quality of these coatings. We are able to achieve precision growth of single and multilayer films to significantly reduce reflection losses for this region of spectrum and provide tailored, repeatable performance targeted for specific applications.

Jewell, April D.; Hennessy, John; Hoenk, Michael E.; Nikzad, Shouleh

2013-09-01

352

Calcium phosphate coatings: A comparative study between simultaneous vapor deposition and electron beam deposition techniques  

Microsoft Academic Search

A comparative study on calcium phosphate coatings produced by two different physical vapor deposition techniques namely, simultaneous vapor deposition (SVD) and electron beam deposition (EBD), has been carried out. All the as-deposited films were annealed at various temperature levels to achieve crystalline structure. The films produced were studied using X-ray diffraction and Rutherford backscattering spectroscopy. Surface morphological studies were conducted

M. Hamdi; Ari-Ide Ektessabi

2006-01-01

353

The structural consequences of calcium crystal deposition.  

PubMed

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

Durcan, Laura; Bolster, Ferdia; Kavanagh, Eoin C; McCarthy, Geraldine M

2014-05-01

354

Development of Lithium Deposition Techniques for TFTR  

SciTech Connect

The ability to increase the quantity of lithium deposition into TFTR beyond that of the Pellet Injector while minimizing perturbations to the plasma provides interesting experimental and operational options. Two additional lithium deposition tools were developed for possible application during the 1996 Experimental Schedule: a solid lithium target probe for real-time deposition, and a lithium effusion oven for deposition between discharges. The lithium effusion oven was operated in TFTR to deposit lithium on the Inner Limiter in the absence of plasma. This resulted in the third highest power TFTR discharge.

Gorman, J.; Johnson, D.; Kugel, H.W.; Labik, G.; Lemunyan, G.; et al

1997-10-01

355

Development of lithium deposition techniques for TFTR  

SciTech Connect

The ability to increase the quantity of lithium deposition into TFTR beyond that of the Pellet Injector while minimizing perturbations to the plasma provides interesting experimental and operational options. Two additional lithium deposition tools were developed for possible application during the 1996 Experimental Schedule: a solid lithium target probe for real-time deposition, and a lithium effusion oven for deposition between discharges. The lithium effusion oven was operated in TFTR to deposit lithium on the Inner Limiter in the absence of plasma. This resulted in the third highest power TFTR discharge.

Kugel, H.W.; Gorman, J.; Johnson, D.; Labik, G.; Lemunyan, G.; Mansfield, D.; Timberlake, J.; Vocaturo, M.

1997-10-01

356

Silicidation of Niobium Deposited on Silicon by Physical Vapor Deposition  

SciTech Connect

Niobium was deposited by physical vapor deposition (PVD) using e-beam evaporation on bare (100) silicon substrates and SiO2 surfaces. The formation of niobium silicide was investigated by annealing PVD Nb films in the temperatures range 400–1000°C. At all elevated annealing temperatures the resistivity of Nb silicide is substantially higher than that of Nb. The Nb silicidation as a function of temperature has been investigated and different NbXSiy compounds have been characterized. It has been observed that the annealing of the Nb film on Si is accompanied by a strong volume expansion of about 2.5 of the resulting reacted film. The films' structural properties were studied using X-Ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM), which was not previously presented in the context of the extant NbSi literature. The X-Ray diffraction characterization of the Nb on Si sample annealed at 1000°C, showed the presence of hexagonal Nb5Si3 phases, with a dominant peak at the (200) plane, and NbSi2 phases. Fractal dimension calculations indicate a distinct transition from Stranski-Krastanov to Volmer-Weber film growth for NbSi formation at the annealing temperature of 600°C and above.

Coumba Ndoye, Kandabara Tapily, Marius Orlowski, Helmut Baumgart, Diefeng Gu

2011-07-01

357

Inhomogeneity of calcium phosphate coatings deposited by laser ablation at high deposition rate  

Microsoft Academic Search

.   Calcium phosphate coatings were deposited with a KrF excimer laser onto titanium alloy to study their homogeneity. Deposition\\u000a was performed at a high deposition rate under a water vapour atmosphere of 45 Pa and at a substrate temperature of 575 C.\\u000a Samples were also submitted to annealing under the same conditions of deposition for different times just after deposition.\\u000a The effects

J. M. Fernández-Pradas; G. Sardin; J. L. Morenza

2003-01-01

358

Carbonate Deposition on Antarctic Shelves  

NASA Astrophysics Data System (ADS)

Limestones associated with glaciomarine deposits occur throughout the geologic record but remain poorly understood. The best-described examples formed during major ice ages of the Neoproterozoic and Late Paleozoic. Quaternary analogs on Antarctic shelves have received comparatively little study. Here, we report on the composition, spatial distribution, and stratigraphic context of carbonate sediments contained in piston cores from the Ross Sea. The goals of this work are to (1) document the nature and distribution of carbonate sediments on the Ross Sea continental shelf and (2) examine temporal relationships to Quaternary glaciation. Results will be used to develop criteria that will improve understanding of analogous deposits in the ancient record. All carbonate-rich intervals in piston cores from the Ross Rea, now housed at the Antarctic Marine Geology Research Facility at Florida State University, were examined and described in detail. Sediment samples were disaggregated and sieved into size fractions before description with paleontological analysis carried out on the coarsest size fraction (>250 microns). Carbonate-rich sediments are concentrated in the northwestern Ross Sea, along the distal margins of Mawson and Pennell Banks. Calcareous facies include a spectrum of lithologies that range from fossiliferous mud, sand, and gravel to skeletal floatstone-rudstone and bafflestone. Floatstone-rudstone and bafflestone is most abundant along western-facing slopes in areas protected from the Antarctic Coastal Current. Sand-prone facies dominate the tops of banks and mud-prone, often spicultic, facies occur in deeper areas. The carbonate factory is characterized by a low-diversity, heterozoan assemblage that is dominated by stylasterine hydrocorals, barnacles, and bryozoans. Molluscs and echinoids are present but not abundant. Planktic and benthic foraminifera are ubiquitous components of the sediment matrix, which is locally very rich in sponge spicules. Biota rarely occur in growth position. Rather, there is much evidence of postdepositional reworking so that these carbonates accumulate as clastic sediments. Available radiocarbon ages place deposition during the transition from MIS 3 to MIS 2, during a time of glacial expansion. Accumulation ceased during the Last Glacial Maximum and so calcareous sediments in the Ross Sea are restricted in both time and space. Deposition occured during windows of time when subdued siliciclastic input and high trophic resource availablity combined to create conditions that favor cold-water carbonate production. Results provide a context for interpreting older carbonates recovered in drillcores from more proximal regions of the Ross Sea.

Frank, T. D.; James, N. P.; Malcolm, I.

2011-12-01

359

Ion beam deposited protective films  

NASA Technical Reports Server (NTRS)

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.

Mirtich, M. J.

1981-01-01

360

Chemical vapor deposition of sialon  

SciTech Connect

A laminated composite and a method for forming the composite by chemical vapor deposition. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200/sup 0/ C; and impinging a gas containing in a flowing atmosphere of air N/sup 2/, SiCl/sub 4/, and AlCl/sub 3/ on the surface.

Casey, A.W.; Landingham, R.L.

1982-06-22

361

Phyllosilicate Deposits in Shalbatana Vallis  

NASA Technical Reports Server (NTRS)

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.

Wintzer, Anne E.; Allen, Carlton C.; Oehler, Dorothy Z.

2011-01-01

362

Economic considerations of atmospheric deposition  

SciTech Connect

Major considerations of the acidic deposition issue which will impact an economic analysis can be divided into two categories: welfare analysis and impact analysis. Welfare analysis involves estimation of receptor-specific benefits of a change in levels of atmospheric deposition. Impact analysis involves the translation of receptor-specific benefits to estimates of regional changes in income, employment, and population due to various emissions control policies and, ultimately, to changes in consumer surplus and gross national product. Of the two, welfare analysis is the most problematic. There are basically two reasons for this. First, all of the benefits estimates for individual receptor systems (i.e., forests, crops, materials, etc.) do not take into account price adjustments in other sectors of the economy which may occur as an indirect result of emissions reduction policies. Secondly, the welfare measures used in the individual receptor systems are not always theoretically consistent with one another (even though they are all calculated in constant-dollar terms).

Shriner, D.S.

1987-01-01

363

Deposition Step in MEMS Time Multiplexed Etch  

NASA Astrophysics Data System (ADS)

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.

Overzet, Lawrence; Saraf, Iqbal; Goeckner, Matthew

2011-11-01

364

Particle deposition onto charge-heterogeneous substrates.  

PubMed

The deposition of model colloidal particles onto striped charge-heterogeneous surfaces was studied to determine the influence of surface chemical heterogeneity on the deposit morphology. The charge heterogeneity was created employing self-assembled monolayers of carboxyl- and amine-terminated alkanethiols using a soft lithographic technique. Polystyrene sulfate microspheres and fluorescent polystyrene nanoparticles were sequentially deposited onto the patterned substrate under no flow (quiescent) condition. The deposited structures and the micropatterns were imaged using a combination of phase contrast and fluorescence microscopy. The experimental particle deposition behavior was compared to predictions based on random sequential adsorption (RSA) employing a Monte Carlo technique. Comparison of radial distribution obtained from experimental data was made with the theoretical results and found to be in good agreement despite the use of a simple binary probabilistic model in the simulations. The primary conclusion from the study is that particles tend to preferentially deposit at the edges of the favorable stripes. However, the extent of this bias can be controlled by the proximity of consecutive favorable stripes (or width of the intervening unfavorable stripes) as well as the particle size relative to the stripe width. Second, a simple binary probability distribution-based Monte Carlo RSA deposition model adequately predicts the deposit structure, particularly the periodicity of the underlying patterns on the substrate. These observations suggest that the patterns could be encrypted by the deposited particles, which can subsequently be decoded, given the proper "key" or information that is based on analyzing the deposit morphology. PMID:19281269

Rizwan, Tania; Bhattacharjee, Subir

2009-05-01

365

Deposition and structure of chemically vapor deposited nanoscale Ti-Si islands on Si  

NASA Astrophysics Data System (ADS)

Nanoscale islands of Ti-Si were formed by chemical vapor deposition onto a Si substrate. The islands were deposited by the H2 reduction of TiCl4 either without or with a Si-containing gas added during deposition. The Ti deposition rate increases strongly with increasing deposition temperature below 690 °C, but it increases only slowly at higher temperatures. For a fixed deposition time at the lower temperatures, the number of islands after deposition changes only slowly as the amount of Ti deposited (and the deposition temperature) varies, but the number of Ti atoms in each island changes rapidly. Adding Si from the gas phase during deposition does not change the amount of Ti deposited, but it increases the height of the deposited islands above the substrate surface plane. The amount of Si-containing gas needed to form stoichiometric TiSi2 increases with decreasing deposition temperature. The island position can be controlled by depositing on a structured Si surface.

Kamins, T. I.; Ohlberg, D. A. A.; Williams, R. Stanley

2004-11-01

366

Oil shales, evaporites and ore deposits  

NASA Astrophysics Data System (ADS)

The relationships between oil shales, evaporites and sedimentary ore deposits can be classified in terms of stratigraphic and geochemical coherence. Oil shale and black shale deposition commonly follows continental red beds and is in turn followed by evaporite deposition. This transgressive-regressive sequence represents an orderly succession of depositional environments in space and time and results in stratigraphic coherence. The amount of organic carbon of a sediment depends on productivity and preservation, both of which are enhanced by saline environments. Work on Great Salt Lake. Utah, allows us to estimate that only 5% of TOC originally deposited is preserved. Inorganic carbonate production is similar to TOC production, but preservation is much higher. Oil shales and black shales commonly are enriched in heavy metals through scavenging by biogenic particles and complexation by organic matter. Ore deposits are formed from such rocks through secondary enrichment processes, establishing a geochemical coherence between oil shales and ore deposits. The Permian Kupferschiefer of N. Europe is used as an example to define a Kupferschiefer type (KST) deposit. Here oxygenated brines in contact with red beds become acidified through mineral precipitation and acquire metals by dissolving oxide coatings. Oxidation of the black shale leads to further acid production and metal acquisition and eventually to sulfide deposition along a reducing front. In order to form ore bodies, the stratigraphic coherence of the red bed-black shale-evaporite succession must be joined by the geochemical coherence of the ore body-evaporite-black shale association. The Cretaceous Cu-Zn deposits of Angola, the Zambian Copperbelt as well as the Creta, Oklahoma, deposits are other KST examples. In the Zambian Copperbelt, evaporites are indicated by the carbonate lenticles thought to be pseudomorphs after gypsum-anhydrite nodules. MVT deposits are also deposited by acid brines, but at more elevated temperatures and with carbonates as principal host rocks. The Pine Point deposits are cited for their close association with evaporites. Alkaline, metal-rich brines are postulated for the HYC deposit of McArthur River, Australia. Such brines are known from the Green River Formation and deposits formed from such brines constitute the GRT class. They can be recognized by the presence of Magadi-type cherts and zeolite-analcime-K-spar tuffs. The Cu-Co ore bodies of Outokumpu, Finland, might also belong to this type. A new classification of sedimentary ore deposits is proposed, based on their geochemical environment. KST and MVT are formed from acid ore fluids, while GRT and CT (Creede type) are derived from basic ore fluids. pH of the fluids is best evaluated not from the ores themselves, but from their effect on the host-rocks.

Eugster, Hans P.

1985-03-01

367

Modeling particle deposition on HVAC heat exchangers  

SciTech Connect

Fouling of fin-and-tube heat exchangers by particle deposition leads to diminished effectiveness in supplying ventilation and air conditioning. This paper explores mechanisms that cause particle deposition on heat exchanger surfaces. We present a model that accounts for impaction, diffusion, gravitational settling, and turbulence. Simulation results suggest that some submicron particles deposit in the heat exchanger core, but do not cause significant performance impacts. Particles between 1 and 10 {micro}m deposit with probabilities ranging from 1-20% with fin edge impaction representing the dominant mechanism. Particles larger than 10 {micro}m deposit by impaction on refrigerant tubes, gravitational settling on fin corrugations, and mechanisms associated with turbulent airflow. The model results agree reasonably well with experimental data, but the deposition of larger particles at high velocities is underpredicted. Geometric factors, such as discontinuities in the fins, are hypothesized to be responsible for the discrepancy.

Siegel, J.A.; Nazaroff, W.W.

2002-01-01

368

Sputter deposition of nanocones for field emission  

SciTech Connect

Deposition into micron-sized holes is known to produce cone shapes as supported on substrates. Potential uses for the cones include field-forming devices as field ionizers and field emission cathodes. The application of such devices include flat panel displays and flash x-ray tubes. Process iterations to closely space arrays of sharp cones have been extensively documented during the past two decades using the physical vapor deposition method of evaporation. Sputter deposition is well known as a method to fill holes and trenches but has only recently been demonstrated as an alternative method to produce field emission cathodes. In a further reduction in size, we have been successful in demonstrating the ability to deposit a cone shape into a cavity with a 300nm diameter hole. Through comparison to the results of electron-beam evaporative deposition, a sputter deposited nanocone appears to be suitable for use as a field emission cathode.

Jankowski, A.F.; Hayes, F.P.

1997-07-01

369

Comparison of Power Deposition in Xiaoping Ding  

E-print Network

.6054.121*10-2100%W 33.1156.623*10-2100%HG 24.7804.956*10-280%WC+20%Water Power Dep. (kW) Energy Dep. (GeV) Shielding of Energy Deposition Beryllium Mercury #12;Part 2: Energy Deposition 8GeV & 4MW Proton beam 2V] Regional Name #12;Part 2: Energy Deposition 8GeV & 4MW Proton beam 3.950*10-31.784*10-2SCSol #13 4

McDonald, Kirk

370

Mathematical Model For Deposition Of Soot  

NASA Technical Reports Server (NTRS)

Semiempirical mathematical model predicts deposition of soot in tubular gas generator in which hydrocarbon fuel burned in very-fuel-rich mixture with pure oxygen. Developed in response to concern over deposition of soot in gas generators and turbomachinery of rocket engines. Also of interest in terrestrial applications involving fuel-rich combustion or analogous process; e.g., purposeful deposition of soot to manufacture carbon black pigments.

Makel, Darby B.

1991-01-01

371

FTIR analysis of aviation fuel deposits  

NASA Technical Reports Server (NTRS)

Five modes of operation of the Nicolet 7199 Fourier Transform Infrared Spectrophotometer have been evaluated for application in analysis of the chemical structure of accelerated storage/thermal deposits produced by jet fuels. Using primarily the absorption and emission modes, the effects of fuel type, stress temperature, stress time, type of spiking agent, spiking agent concentration, fuel flow, and post-depositional treatment on the chemical nature of fuel deposits have been determined.

Helmick, L. S.; Seng, G. T.

1984-01-01

372

Electroless Deposition Approaching the Molecular Scale  

Microsoft Academic Search

\\u000a Electroless deposition (ELD) encompasses quite a range of chemical deposition processes at the solid\\/liquid interface. Here\\u000a I focus exclusively on autocatalytic ELD of metals, i.e., the plated metal catalyzes its own deposition, and hence the process\\u000a is continuous as long as sufficient amounts of reactants are provided [1–5]. Such a reaction requires a catalytic site to\\u000a start; usually this is

A. M. Bittner

373

Thick boride coatings by chemical vapor deposition  

Microsoft Academic Search

This paper describes an experimental study of the chemical vapor deposition (CVD) of TiBâ by the hydrogen reduction of TiClâ and BClâ with the purpose of obtaining very thick(>100 ..mu..m) and uniform coatings. The optimum deposition conditions were: temperature: 900 to 950°, source gas ratios: Ti\\/B = 1\\/2 and H\\/Cl = 6\\/1. With these conditions, deposition rates greater than 25

H. O. Pierson; A. W. Mullendore

1982-01-01

374

Vapor deposited release layers for nanoimprint lithography  

Microsoft Academic Search

This paper presents the advantages of using a vapor deposited self-assembled monolayer (SAM) as a mold release layer for nano-imprint lithography. The release SAM was formed from a perfluorinated organo-silane precursor at room temperature in the gaseous state by a technique called Molecular Vapor Deposition (MVDTM). In contrast to a conventional coating from a liquid immersion sequence, the vapor deposition

Tong Zhang; Boris Kobrin; Mike Wanebo; Romek Nowak; Richard Yi; Jeff Chinn; Markus Bender; Andreas Fuchs; Martin Otto

2006-01-01

375

Large Area Vacuum Deposited Coatings  

SciTech Connect

It's easy to make the myriad of types of large area and decorative coatings for granted. We probably don't even think about most of them; the low-e and heat mirror coatings on our windows and car windows, the mirrors in displays, antireflection coatings on windows and displays, protective coatings on aircraft windows, heater coatings on windshields and aircraft windows, solar reflectors, thin film solar cells, telescope mirrors, Hubble mirrors, transparent conductive coatings, and the list goes on. All these products require large deposition systems and chambers. Also, don't forget that large batches of small substrates or parts are coated in large chambers. In order to be cost effective hundreds of ophthalmic lenses, automobile reflectors, display screens, lamp reflectors, cell phone windows, laser reflectors, DWDM filters, are coated in batches.

Martin, Peter M.

2003-04-30

376

Laser Induced Chemical Liquid Phase Deposition (LCLD)  

SciTech Connect

Laser induced chemical deposition (LCLD) of metals onto different substrates attracts growing attention during the last decade. Deposition of metals onto the surface of dielectrics and semiconductors with help of laser beam allows the creation of conducting metal of very complex architecture even in 3D. In the processes examined the deposition occurs from solutions containing metal ions and reducing agents. The deposition happens in the region of surface irradiated by laser beam (micro reactors). Physics -chemical reactions driven by laser beam will be discussed for different metal-substrate systems. The electrical, optical, mechanical properties of created interfaces will be demonstrated also including some practical-industrial applications.

Nanai, Laszlo; Balint, Agneta M. [University of Szeged, JGYPK, Department of General and Environmental Physics H-6725 Szeged, Boldogasszony sgt. 6 (Hungary); West University of Timisoara, Faculty of Physics, Department of Physics, Bulv. V. Parvan 4, Timisoara 300223 (Romania)

2012-08-17

377

Nitrate deposition and impact of Adirondack streams  

SciTech Connect

Acidic deposition has a great impact on water chemistry and fish populations in the Adirondack region. Although the Clean Air Act Amendments of 1990 have resulted in some reductions of sulfur deposition, nitrate deposition has not yet been well controlled, and continues to impact aquatic resources. As part of the USEPA funded Episodic Response Project, four Adirondack headwater streams were intensively monitored over an 18 month period. Atmospheric deposition was also monitored at a centrally located station. The quantity of nitrate being deposited on the study watersheds was calculated based on monthly net deposition data, which ranged from 0.6 kg/ha/month to 3.6 kg/ha/month. These data were then compared to the monthly export of nitrate from the watershed in these streams. Nitrate concentrations were highest in the stream water during the spring snowmelt period prior to the time when forest vegetation actively utilizes nitrate. On an annual basis, the amount of nitrate that left the watershed via stream water was approximately equal to the amount that fell as nitrate deposition. These data are important in documenting the impact that nitrate has in acidifying Adirondack streams during the spring, which coincides with brook trout hatching. Control programs for nitrous oxide emissions are presently aimed at reducing ozone levels during the May--September period. These emissions control programs need to be expanded to also reduce nitrate deposition in the sensitive Adirondack region during the water and spring periods when nitrate deposition has its greatest impact on aquatic resources.

Simonin, H.A. [New York State Dept. of Environmental Conservation, Rome, NY (United States). Rome Field Station; Kretser, W. [New York State Dept. of Environmental Conservation, Ray Brook, NY (United States). Adirondack Lakes Survey Corp.

1995-12-31

378

A Brief History of Deposit Insurance  

NSDL National Science Digital Library

Published by the Federal Deposit Insurance Corporation (FDIC) for the September 1998 International Conference on Deposit Insurance, A Brief History of Depository Insurance focuses on the insurance function of the FDIC. Over 60 pages cover the antecedents of Federal Deposit Insurance and the establishment of the FDIC as well as the Banking Act of 1935, the effects of WWII, and current bank industry issues such as the Year 2000 date change. In addition, three appendices chronicle bank insurance fund failures and losses, 1934-1997, insured deposits and the Bank Insurance Fund, 1934-1997, and income and expenses of the Bank Insurance Fund, 1933-1997.

379

ESTIMATES OF CLOUD WATER DEPOSITION AT MOUNTAIN DEPOSITION AT MOUNTAIN ACID DEPOSITION PROGRAM SITES IN THE APPALACHIAN MOUNTAINS  

EPA Science Inventory

Cloud water deposition was estimated at three high elevation sites in the Appalachian Mountains of the eastern United States (Whiteface Mountain, NY, Whitetop Mountain, VA, and Clingrnan's Dome, TN) from 1994 through 1999 as part of the Mountain Acid Deposition Program (MADPro). ...

380

76 FR 7740 - Amendments to Deposit Insurance Regulations: Deposit Insurance Coverage Training; SMDIA Notification  

Federal Register 2010, 2011, 2012, 2013

...proposing a rule that would promote public confidence in Federal deposit insurance by providing...the potential to undermine customer confidence in depository institutions and the...benefit to depositors by reinforcing their confidence in Federal deposit insurance and...

2011-02-11

381

Tandem solar cells deposited using hot-wire chemical vapor deposition  

Microsoft Academic Search

The hot-wire chemical vapor deposition technique was used for the deposition of amorphous and microcrystalline silicon. The best microcrystalline silicon solar cells were deposited at the edge of the transition from the microcrystalline to the amorphous regime. Under conditions that are close to this edge, the crystalline ratio decreased with accumulated film thickness, due to changes in the filament properties

M. K. van Veen; R. E. I. Schropp

2004-01-01

382

Inhomogeneity of calcium phosphate coatings deposited by laser ablation at high deposition rate  

NASA Astrophysics Data System (ADS)

Calcium phosphate coatings were deposited with a KrF excimer laser onto titanium alloy to study their homogeneity. Deposition was performed at a high deposition rate under a water vapour atmosphere of 45 Pa and at a substrate temperature of 575 °C. Samples were also submitted to annealing under the same conditions of deposition for different times just after deposition. The effects of the annealing were also investigated. The morphology of the coatings was studied by scanning electron microscopy. Their structure and phase distribution was analysed by X-ray diffractometry and infrared and micro-Raman spectroscopies. Besides the non-uniform thickness, the results reveal an inhomogeneity in the spatial distribution of calcium phosphate phases in the coatings. The phase distribution can be almost completely correlated with the deposition rate. High deposition rates (0.5 nm/pulse) occurring in the centre of deposition results in the formation of amorphous calcium phosphate, while lower deposition rates favour the presence of hydroxyapatite and alpha tricalcium phosphate. At intermediate deposition rates, beta tricalcium phosphate is found, probably because the superimposed effect of energetic particles bombardment. The annealing process promotes the crystallisation of the amorphous material. The importance of the deposition rate in the phases obtained is stated after comparing these results with a previous work where homogeneous hydroxyapatite coatings were obtained under the same conditions of laser fluence, temperature and pressure, but at lower deposition rates.

Fernández-Pradas, J. M.; Sardin, G.; Morenza, J. L.

383

Properties of Coatings: Comparisons of Electroplated, Physical Vapor Deposited, Chemical Vapor Deposited, and Plasma Sprayed Coatings  

Microsoft Academic Search

Properties of coatings (structure, porosity, density, stress, corrosion, hydrogen permeation, adhesion, tribology, fatigue and thermal contact conductance) produced by a number of deposition methods including electrodeposition, physical vapor deposition, chemical vapor deposition, and flame spraying art; compared. In most cases, the films did not exhibit similar properties. In addition, process conditions often could be varied for any given coating process

J. W. Dini

1997-01-01

384

Characterization of PWR steam generator deposits  

Microsoft Academic Search

Restoring the thermal performance of the steam generators often requires the utility to remove deposits by expensive chemical means. This work demonstrates that careful characterization of secondary side deposit samples can reveal their chemical and physical properties which in turn contribute to an overall assessment of the need for and extent of steam generator inspection and maintenance. More specifically, knowledge

Varrin; R. Jr

1996-01-01

385

Grade and Tonnage Relationships Among Copper Deposits  

USGS Publications Warehouse

Three types of copper deposits-porphyry, strata-bound, and massive sulfide-are described, and the distributions of tonnages and grades for 267 deposits are compared with normal and lognormal frequency distributions. The relationships between grades and tonnages are analyzed by examining the correlation coefficients of these variables. Conclusions reached include the following: (1) Geologic factors influencing tonnage of a particular deposit type are probably distinct from those influencing grade; (2) frequency distributions of tonnages and grades approximate lognormality, making it possible to predict probability of various tonnage-grade classes and to test correlation between variables; (3) no significant correlation was found between tonnage and grade for porphyry or strata-bound deposits; ( 4) significant negative correlation between tonnage and grade was found for the massive sulfide subset, probably reflecting a mixture of high-grade low-tonnage massive ores, low-grade high-tonnage stockwork, and disseminated ores characteristic of some massive sulfide deposits; (5) significant negative correlation was found between tonnage and grade for the mixture of deposit types in the whole sample. Extrapolation on the basis of the negative grade-tonnage correlation shown for the mixed population seems to imply the occurrence of large-tonnage very low grade deposits, which could be important in supplying future copper needs. This extrapolation is misleading, however, for both statistical and geological reasons. Furthermore, large-tonnage very low grade deposits in the porphyry class of the population are found to be very rare occurrences.

Singer, D.A.; Cox, Dennis P.; Drew, Lawrence J.

1975-01-01

386

Preparation Of Sources For Plasma Vapor Deposition  

NASA Technical Reports Server (NTRS)

Multicomponent metal targets serving as sources of vapor for plasma vapor deposition made in modified pressureless-sintering process. By use of targets made in modified process, one coats components with materials previously plasma-sprayed or sintered but not plasma-vapor-deposited.

Waters, William J.; Sliney, Hal; Kowalski, D.

1993-01-01

387

Time Resolved Deposition Measurements in NSTX  

SciTech Connect

Time-resolved measurements of deposition in current tokamaks are crucial to gain a predictive understanding of deposition with a view to mitigating tritium retention and deposition on diagnostic mirrors expected in next-step devices. Two quartz crystal microbalances have been installed on NSTX at a location 0.77m outside the last closed flux surface. This configuration mimics a typical diagnostic window or mirror. The deposits were analyzed ex-situ and found to be dominantly carbon, oxygen, and deuterium. A rear facing quartz crystal recorded deposition of lower sticking probability molecules at 10% of the rate of the front facing one. Time resolved measurements over a 4-week period with 497 discharges, recorded 29.2 {micro}g/cm{sup 2} of deposition, however surprisingly, 15.9 {micro}g/cm{sup 2} of material loss occurred at 7 discharges. The net deposited mass of 13.3 {micro}g/cm{sup 2} matched the mass of 13.5 {micro}g/cm{sup 2} measured independently by ion beam analysis. Monte Carlo modeling suggests that transient processes are likely to dominate the deposition.

C.H. Skinner; H. Kugel; A.L. Roquemore; J. Hogan; W.R. Wampler; the NSTX team

2004-08-03

388

Intelligent rapid prototyping with fused deposition modelling  

Microsoft Academic Search

Explains that fused deposition modelling is a rapid prototyping technology by which physical objects are created directly from a CAD model using layer by layer deposition of extruded material. The technology offers the potential of producing parts accurately in a wide range of materials safely and quickly. In using this technology, the designer is often confronted with a host of

Syed H. Masood

1996-01-01

389

Monolayer thickness in atomic layer deposition  

Microsoft Academic Search

The growth rate in atomic layer deposition (ALD) or epitaxy (ALE) is usually saturated to a constant level when appropriate operation conditions are attained. The layer thickness deposited in one cycle is limited by adsorption. A simple molecular description for chemisorption and surface reactions is suggested and shows that both reaction steps have an effect on the growth rate. A

Markku Ylilammi

1996-01-01

390

Dry deposition of sulfate onto surrogate surfaces  

Microsoft Academic Search

Measurements of SOâ\\/sup 2 -\\/ fluxes to surrogate surfaces have been conducted as part of the Dry Deposition Intercomparison Study in Champaign, Illinois. Data for Teflon plates without rims and for polycarbonate petri dishes with 1-cm rims have been obtained and compared with data for Teflon sheets and polyethylene dustfall buckets used by other investigators. Results show that deposition velocities

Cliff I. Davidson; L. G. Cartwright; L. R. Landis; S. E. Lindberg; J. A. Schmidt

1985-01-01

391

Metalliferous black shales and related ore deposits  

SciTech Connect

This book comprises papers and extended abstracts dealing with a variety of topics including the geochemistry and organic geochemistry of several black shale formations: the nature of modern Black Sea sediments: metal- organic complexes in ore fluids; black shales related to disseminated gold deposits; vanadium concentrations and molybdenum-nickel deposits; and the problem of defining metalliferous black shales.

Grauch, R.I. (Geological Survey, Reston, VA (United States)); Huyck, H.L.O. (Cincinnati Univ., OH (United States))

1990-01-01

392

Modern eolian dust deposition in central Asia  

Microsoft Academic Search

Glaciers around the globe provide a unique medium for investigating the temporal and spatial variation of dust deposition. Here we investigate the spatial and seasonal distribution of eolian dust deposition in central Asia through the analysis of concentrations and size distributions of insoluble particles (over the size range 1 22mum diameter) in snow and ice samples collected from eight glaciers

C. P. Wake; P. A. Mayewski; Z. Li; J. Han; D. Qin

1994-01-01

393

29 CFR 2200.56 - Depositions.  

Code of Federal Regulations, 2010 CFR

...expect to introduce at the hearing. Four working days thereafter...presentation of evidence at a hearing. Unless physically incapacitated...used during the deposition. Sound levels will be altered only...videotaped deposition is used at the hearing, the original of the...

2010-07-01

394

Regional aerosol deposition in human upper airways  

SciTech Connect

During the current report experimental studies of upper respiratory deposition of radon progeny aerosols and stimulant aerosols were carried out in replicate casts of nasal and oral passages of adults and children. Additionally, preliminary studies of nasal passage deposition of unattached Po{sup 218} particles was carried out in four human subjects. Data on nasal inspiratory deposition in replicate models of adults and infants from three collaborating laboratories were compared and a best-fit curve of deposition efficiency for both attached and unattached particles was obtained, showing excellent inter-laboratory agreement. This curve demonstrates that nasal inspiratory deposition of radon progeny is weakly dependent upon flow rate over physiologically realistic ranges of flow, does not show a significant age effect, and is relatively independent of nasal passage dimensions for a given age range. Improved replicate models of the human adult oral passage extending to the mid-trachea were constructed for medium and higher flow mouth breathing states; these models were used to assess the deposition of unattached Po{sup 218} particles during oronasal breathing in the oral passage and demonstrated lower deposition efficiency than the nasal passage. Measurements of both Po{sup 218} particle and attached fraction particle size deposition were performed in replicate nasal passage of a four week old infant. 5 refs., 1 fig.

Swift, D.L.

1991-11-01

395

Chemical solution deposition of electronic oxide films  

Microsoft Academic Search

The chemical solution deposition (CSD) technique as a highly flexible method for the fabrication of electronic oxide thin films is reviewed. Various chemical aspects of different approaches are discussed, including sol–gel, hybrid, and metallo-organic decomposition (MOD) routes, which all have been successfully applied for the deposition of this class of materials. Principles of the selection and properties of the educts,

Robert W. Schwartz; Theodor Schneller; Rainer Waser

2004-01-01

396

ADVANCES IN CONTROL TECHNOLOGY FOR ACID DEPOSITION  

EPA Science Inventory

Causes and effects of acid deposition are the subject of widespread discussion both in the U.S. and Europe. Two major concerns are the acidification of lakes and streams, and forest damage. The proposed mechanism for acidification of lakes and streams is the deposition of acidic ...

397

Focused helium-ion-beam-induced deposition  

NASA Astrophysics Data System (ADS)

The recent introduction of the helium ion microscope (HIM) offers new possibilities for materials modification and fabrication with spatial resolution below 10 nm. In particular, the specific interaction of He+ ions in the tens of keV energy range with materials—i.e., minimal deflection and mainly energy loss via electronic excitations—renders the HIM a special tool for ion-beam-induced deposition. In this work, an overview is given of all studies of helium-ion-beam-induced deposition (He-IBID) that appeared in the literature before summer 2014. Continuum models that describe the deposition processes are presented in detail, with emphasis on precursor depletion and replenishment. In addition, a Monte Carlo model is discussed. Basic experimental He-IBID studies are critically examined. They show deposition rates of up to 0.1 nm3/ion. Analysis by means of a continuum model yields the precursor diffusion constant and the cross sections for beam-induced precursor decomposition and beam-induced desorption. Moreover, it is shown that deposition takes place only in a small zone around the beam impact point. Furthermore, the characterization of deposited materials is discussed in terms of microstructure and resistivity. It is shown that He-IBID material resembles more electron-beam-induced-deposition (EBID) material than Ga-ion-beam-induced-deposition (Ga-IBID) material. Nevertheless, the spatial resolution for He-IBID is in general better than for EBID and Ga-IBID; in particular, proximity effects are minimal.

Alkemade, P. F. A.; Miro, H.

2014-09-01

398

Atmospheric deposition maps for the Rocky Mountains  

NASA Astrophysics Data System (ADS)

Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountains by using spatial statistics. A parameter-elevation regressions on independent slopes model (PRISM) was incorporated to account for variations in precipitation amount over mountainous regions. Chemical data were obtained from the National Atmospheric Deposition Program/National Trends Network and from annual snowpack surveys conducted by the US Geological Survey and National Park Service, in cooperation with other Federal, State and local agencies. Surface concentration maps were created by ordinary kriging in a geographic information system, using a local trend and mathematical model to estimate the spatial variance. Atmospheric-deposition maps were constructed at 1-km resolution by multiplying surface concentrations from the kriged grid and estimates of precipitation amount from the PRISM model. Maps indicate an increasing spatial trend in concentration and deposition of the modeled constituents, particularly nitrate and sulfate, from north to south throughout the Rocky Mountains and identify hot-spots of atmospheric deposition that result from combined local and regional sources of air pollution. Highest nitrate (2.5-3.0 kg/ha N) and sulfate (10.0-12.0 kg/ha SO 4) deposition is found in northern Colorado.

Nanus, Leora; Campbell, Donald H.; Ingersoll, George P.; Clow, David W.; Alisa Mast, M.

399

Global reactive nitrogen deposition from lightning NOx  

Microsoft Academic Search

We present results of the deposition of nitrogen compounds formed from lightning (LNOx) using the global chemical transport Model of Atmospheric Transport and Chemistry–Max Planck Institute for Chemistry version. The model indicates an approximately equal deposition of LNOx in both terrestrial and oceanic ecosystems, primarily in the tropics and midlatitudes open ocean, despite much higher intensities of lightning flashes above

A. Shepon; H. Gildor; L. J. Labrador; T. Butler; L. N. Ganzeveld; M. G. Lawrence

2007-01-01

400

Colloidal particle deposition in turbulent flow  

SciTech Connect

A theoretical analysis is presented which describes the initial deposition of monodispersed spherical colloidal particles from a steady fully developed turbulent flow onto conduit walls. When the net particle-conduit electrical interaction potential is attractive, particle deposition is shown to be often governed by turbulent hydrodynamics. When the net particle-conduit electrical interaction potential possess a repulsive maximum, particle deposition to first order is uniform and depends solely on electrical interaction effects. The developed theoretical model specialized to orifice deposition with the use of Harwell Flow3D turbulence modelling software qualitatively described the deposition of 0.5 {mu}m silica particles onto glass orifices from an aqueous suspension. The effect of the electrical double layer on the rate of colloidal particle deposition in laminar flow has been described by Spielman and Friedlander (1), Dahneke (2), Bowen et al. (3) and Bowen and Epstein (4). This article describes the extension of their work to colloidal particle deposition under steady fully developed turbulent flow conditions. This article also reports the results of orifice particle deposition experiments which were conducted to qualitatively investigate the developed theoretical model.

Morton, D.S.

1994-05-01

401

Acid deposition. Environmental, economic, and policy issues  

Microsoft Academic Search

This book presents information on the following topics: Atmospheric acidification chemistry; SOâ oxidation in summertime cloud water at Whiteface Moutain; methods for diagnosing the sources of acid deposition; the use of long range transport models in determining emission control strategies for acid deposition; the sedimentary record of atmospheric pollution in Jerseyfield Lake, Adirondack Mountains, New York; transformation of nitric, sulfuric

D. P. Adams; W. P. Page

1985-01-01

402

Constraining Mercury Oxidation Using Wet Deposition  

E-print Network

Constraining Mercury Oxidation Using Wet Deposition Noelle E. Selin and Christopher D. Holmes mercury oxidation [Selin & Jacob, Atmos. Env. 2008] 30 60 90 120 150 30 60 90 120 150 30 60 90 120 150 30 Influences on Mercury Wet Deposition · Hg wet dep = f(precipitation, [Hg(II)+Hg(P)]) Correlation (r2) between

Selin, Noelle Eckley

403

The Gathering Crisis in Federal Deposit Insurance  

Microsoft Academic Search

The system of federal deposit insurance adopted during the 1930s has become increasingly costly and unreliable. This timely study warns bankers, regulators, politicians, and taxpayers that no matter how well the deposit-insurance system may have run in the past it is headed for an expensive bureaucratic breakdown. It forcefully argues that unless market discipline can be reintroduced, this breakdown threatens

Edward J. Kane

1985-01-01

404

Thick Boride Coatings by Chemical Vapor Deposition.  

National Technical Information Service (NTIS)

This paper describes an experimental study of the chemical vapor deposition (CVD) of TiB sub 2 by the hydrogen reduction of TiCl sub 4 and BCl sub 3 with the purpose of obtaining very thick(>100 mu m) and uniform coatings. The optimum deposition condition...

H. O. Pierson, A. W. Mullendore

1982-01-01

405

Review Concerning Studies of Frost Deposition  

NASA Astrophysics Data System (ADS)

In order to increase the coefficient of performance of heat exchangers under frosting conditions such as in air conditioners, showcases, and unit coolers, it is necessary to elucidate the frost deposition mechanism. The previous studies about frost deposition were summarized in this study. The previous studies about observation of frost deposition, properties of the frost layer, simulation methods of the frost layer, frost detection, frost studies concerning heat exchangers and heat pumps, and defrost control methods were explained. There are many conditions that have not been measured yet, though the mechanism of frost deposition and properties of the frost layer have been elucidated from the previous studies. The study of frost deposition has been invigorated in Japan recently. The understanding of frosting phenomenon is expected to be deepened in the near future.

Yamashita, Koji

406

Atmospheric organic nitrogen deposition explored at workshop  

NASA Astrophysics Data System (ADS)

Atmospheric organic nitrogen (AON) is an important nitrogen component with significant deposition in many natural waters. The range and quality of the data are varied, but deposited organic nitrogen (DON) is ubiquitous globally, both in extent and magnitude.The Environmental Protection Agency's Chesapeake Bay Program (CBP) sponsored a workshop last year to determine what is known about organic nitrogen in atmospheric deposition and to establish research priorities needed to obtain an adequate database for coastal waters such as Chesapeake Bay Working groups at the meeting concluded that AON represents a poorly quantified array of broadly reactive natural and pollutant species; that because of compromises in collection, preservation, and analysis, wet deposition of total organic nitrogen is inadequately quantified and dry deposition is not quantified at all; and that because of a lack of data on bioactive species, the effect of AON and DON on ecosystems is largely unknown.

Church, Thomas M.

407

Microdroplet deposition under a liquid medium.  

PubMed

An experimental and numerical study of the factors affecting the reproducibility of microdroplet depositions performed under a liquid medium is presented. In the deposition procedure, sample solution is dispensed from the end of a capillary by the aid of a pressure pulse onto a substrate with pillar-shaped sample anchors. The deposition was modeled using the convective Cahn-Hilliard equation coupled with the Navier-Stokes equations with added surface tension and gravity forces. To avoid a severe time-step restriction imposed by the fourth-order Cahn-Hilliard equation, a semi-implicit scheme was developed. An axisymmetric model was used, and an adaptive finite element method was implemented. In both the experimental and numerical study it was shown that the deposited volume mainly depends on the capillary-substrate distance and the anchor surface wettability. A critical equilibrium contact angle has been identified below which reproducible depositions are facilitated. PMID:17241029

Villanueva, Walter; Sjödahl, Johan; Stjernström, Mårten; Roeraade, Johan; Amberg, Gustav

2007-01-30

408

Combustion system processes leading to corrosive deposits  

NASA Technical Reports Server (NTRS)

Degradation of turbine engine hot gas path components by high temperature corrosion can usually be associated with deposits even though other factors may also play a significant role. The origins of the corrosive deposits are traceable to chemical reactions which take place during the combustion process. In the case of hot corrosion/sulfidation, sodium sulfate was established as the deposited corrosive agent even when none of this salt enters the engine directly. The sodium sulfate is formed during the combustion and deposition processes from compounds of sulfur contained in the fuel as low level impurities and sodium compounds, such as sodium chloride, ingested with intake air. In other turbine and power generation situations, corrosive and/or fouling deposits can result from such metals as potassium, iron, calcium, vanadium, magnesium, and silicon.

Stearns, C. A.; Kohl, F. J.; Rosner, D. E.

1981-01-01

409

A preliminary deposit model for lithium brines  

USGS Publications Warehouse

This report is part of an effort by the U.S. Geological Survey to update existing mineral deposit models and to develop new ones. The global transition away from hydrocarbons toward energy alternatives increases demand for many scarce metals. Among these is lithium, a key component of lithium-ion batteries for electric and hybrid vehicles. Lithium brine deposits account for about three-fourths of the world’s lithium production. Updating an earlier deposit model, we emphasize geologic information that might directly or indirectly help in exploration for lithium brine deposits, or for assessing regions for mineral resource potential. Special attention is given to the best-known deposit in the world—Clayton Valley, Nevada, and to the giant Salar de Atacama, Chile.

Bradley, Dwight; Munk, LeeAnn; Jochens, Hillary; Hynek, Scott; Labay, Keith

2013-01-01

410

Explosive volcanic deposits on Mars: Preliminary investigations  

NASA Technical Reports Server (NTRS)

Two investigations were undertaken to examine possible large scale explosive volcanic deposits on Mars. The first includes an analysis of Viking Infrared Thermal Mapper (IRTM) data covering the vast deposits in the Amazonis, Memnonia, and Aeolis regions. These postulated ignimbrites have been previously mapped, and at least five high resolution nighttime IRTM data tracks cross the deposits. Preliminary analysis of the data covering Amazonis Planitia show that local features have anomalous thermal inertias but the ignimbrites as a whole do not consistently have significantly different thermal inertias from their surroundings. Preliminary photogeologic and IRTM studies of the large and small highland paterae have also begun. The purpose of IRTM studies of postulated Martian explosive volcanic deposits is to determine the physical properties of the proposed ignimbrites. If volcanic deposits are exposed at the surface, high thermal inertias, as are observed for Apollinaris Patera, should be present.

Crown, D. A.; Leshin, L. A.; Greeley, Ronald

1987-01-01

411

Investigation of LANDSAT imagery on correlations between ore deposits and major shield structures in Finland  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Based on tests, it is obvious that practically all major LANDSAT winter linears found are geologically significant features. Most of them are chains of bogs, lakes, rivers, and cultivated areas covered by ice and/or snow, i.e., unforested linear topographic lows. They need no explanation other than that they are extensive fracture zones of the basement.

Tuominen, H. V. (principal investigator); Kuosmanen, V.

1976-01-01

412

Mesoscale acid deposition modeling studies  

NASA Technical Reports Server (NTRS)

The work performed in support of the EPA/DOE MADS (Mesoscale Acid Deposition) Project included the development of meteorological data bases for the initialization of chemistry models, the testing and implementation of new planetary boundary layer parameterization schemes in the MASS model, the simulation of transport and precipitation for MADS case studies employing the MASS model, and the use of the TASS model in the simulation of cloud statistics and the complex transport of conservative tracers within simulated cumuloform clouds. The work performed in support of the NASA/FAA Wind Shear Program included the use of the TASS model in the simulation of the dynamical processes within convective cloud systems, the analyses of the sensitivity of microburst intensity and general characteristics as a function of the atmospheric environment within which they are formed, comparisons of TASS model microburst simulation results to observed data sets, and the generation of simulated wind shear data bases for use by the aviation meteorological community in the evaluation of flight hazards caused by microbursts.

Kaplan, Michael L.; Proctor, F. H.; Zack, John W.; Karyampudi, V. Mohan; Price, P. E.; Bousquet, M. D.; Coats, G. D.

1989-01-01

413

Tumor deposits in gastric carcinomas.  

PubMed

We performed this study to examine the prevalence of tumor deposits (TD) in gastric adenocarcinomas (GACa), and the relevance of their presence, size and type to clinical outcome. Ninety-six patients, histopathologically diagnosed as GACa following a total/subtotal gastrectomy were included, and clinicopathologic data were recorded. Due to the statistical analysis, the majority of TD(+) cases were of intestinal type and showed vascular invasion. In these cases, the incidence of local recurrence was significantly higher. The majority of GACa of intestinal type with TD were of high grade and showed vascular invasion. Recurrence and death were more commonly encountered among them. The recurrence-free survival (RFS) was significantly shorter in patients with TDs, which was also confirmed by multivariate analysis, and there was a significant difference between both RFS and overall survival of TD(+) and TD(-) cases of intestinal type GACa. In conclusion, in this study, we demonstrate that TDs are not infrequently observed in GACa, they are more commonly associated with the intestinal type and vascular invasive gastric cancers. Our study shows the prognostic impact of TDs, especially regarding the RFS. Therefore, the documentation of TDs might be considered for prospective studies, especially for the intestinal type GACa, a shortcoming of this study. PMID:24726262

Ersen, Ayca; Unlu, Mehtat S; Akman, Tulay; Sagol, Ozgul; Oztop, Ilhan; Atila, Koray; Bora, Seymen; Ellidokuz, Huyla; Sarioglu, Sulen

2014-09-01

414

Fundamentals of Chemical Vapor Deposition  

NSDL National Science Digital Library

This web page offers a tutorial by Daniel M. Dobkin, Ph.D, proprietor of Enigmatics Consulting of Sunnyvale, California that introduces fundamental principles of chemical vapor deposition of films. Topics covered include CVD Basics, Review of Ideal Gases, Review of Kinetic Theory, Zero-Dimensional Transport: Stirred Reactor, Transport in Gaseous Media, Chemistry for CVD, Plasmas for CVD, CVD Films, and CVD Reactor Designs. According to the author, "The tutorial assumes a general background roughly equivalent to a BS degree in the physical sciences. The aspects of thermodynamics, statistical mechanics, chemistry, and electromagnetism needed for understanding CVD processes are reviewed here, but only in sufficient depth to remind the reader of a past acquaintance with the topicsÃÂ. Some knowledge of the basics of semiconductor manufacturing is also helpful in following the discussion of films and applications." Visitors are free to copy and use any materials in the site, so long as licensing conditions stipulated by Creative Commons are met. (Details of the license can be found by clicking on a hyperlink to Creative Commons.)

Dobkin, Daniel M.

2012-12-11

415

Characteristics of dust deposition on suspended insulators during simulated sandstorm  

Microsoft Academic Search

In the present work, we studied the dust deposition characteristics on suspended insulators under the simulated sandstorm conditions in a laboratory. Based on the simulation experiments, the basic dust deposition and distribution characteristics were studied, such as the difference of deposition among sheds at different locations, the difference of deposition between large and small sheds, the relationship between deposition quantity

Bo He; Haiyun Jin; Naikui Gao; Bangfa Chen; Zongren Peng

2010-01-01

416

Structural characterization of MAPLE deposited lipase biofilm  

NASA Astrophysics Data System (ADS)

Lipases (triacylglycerol ester hydrolases) are enzymes used in several industrial applications. Enzymes immobilization can be used to address key issues limiting widespread application at industrial level. Immobilization efficiency is related to the ability to preserve the native conformation of the enzyme. MAPLE (Matrix Assisted Pulsed Laser Evaporation) technique, a laser deposition procedure for treating organic/polymeric/biomaterials, was applied for the deposition of lipase enzyme in an ice matrix, using near infrared laser radiation. Microscopy analysis showed that the deposition occurred in micrometric and submicrometric clusters with a wide size distribution. AFM imaging showed that inter-cluster regions are uniformly covered with smaller aggregates of nanometric size. Fourier transform infrared spectroscopy was used for both recognizing the deposited materia